The Isles of Scilly Biodiversity Audit 2008 - Cornwall Wildlife Trust

The Isles of Scilly Biodiversity Audit 2008 - Cornwall Wildlife Trust

The Isles of Scilly Biodiversity Audit 2008 - Cornwall Wildlife Trust


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<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>Biodiversity</strong> <strong>Audit</strong> <strong>2008</strong>EnvironmentalRecords Centre for<strong>Cornwall</strong> and the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>

ISLES OF SCILLY BIODIVERSITY AUDIT <strong>2008</strong>Written by: Gary Lewis. Rosemary Parslow, Angela Gall and Paul McCartney.Funded by: Aggregates Levy Sustainability FundCopies can be obtained from:Environmental Records Centre for <strong>Cornwall</strong> and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>,Five Acres, Allet, Truro, <strong>Cornwall</strong> TR4 9DJ<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong>Carn Thomas, St Mary’s, <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, TR21 0PTCover photo, White Island viewed from St Martin’s. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page

ContentsForeword Page 5Acknowledgements Page 6Executive Summary Page 71 Introduction Page 91.1 Objectives <strong>of</strong> IoS <strong>Biodiversity</strong> <strong>Audit</strong> Page 91.2 Origins <strong>of</strong> IoS <strong>Biodiversity</strong> <strong>Audit</strong> Page 91.3 What is biodiversity? Page 101.4 <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Page 101.5 <strong>The</strong> marine environment <strong>of</strong> the IoS Page 102. <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> Page 112.1 Biological Records and Sources <strong>of</strong> Information Page 112.2 Summary Statements: Status and Trends Page 122.2.1 Species Page Marine algae Page Charophytes - stoneworts Page Fungi - mushrooms and toadstools Page Lichens Page Bryophytes -mosses and liverworts Page Horsetails, ferns and flowering plants Page Porifera - sponges Page Cnidaria – sea anemones, jellyfish, corals and relatives Page Marine Annelida – worms Page Arachnida - spiders and relatives Page Crustacea – crabs, lobsters, shrimps and relatives Page Myriapoda - centipedes and millipedes Page Odonata - dragonflies and damselflies Page Orthoptera - crickets, grasshoppers and relatives Page Hemiptera - bugs Page Lepidoptera - butterflies and moths Page Diptera - two-winged flies Page 302.2.1.18 Hymenoptera - wasps and bees Page 312.2.1.19 Hymenoptera - ants Page 322.2.1.20 Coleoptera - beetles Page 332.2.1.21 Marine mollusca – slugs, snails, bivalves and relatives Page 342.2.1.22 Terrestrial mollusca – slugs, snails, bivalves and relatives Page 35<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page Bryozoa –sea mats Page 362.2.1.24 Echinodermata – sea urchins, starfish, brittlestars and relatives Page 372.2.1.25 Tunicata – larvaceans, thaliaceans and ascidians Page 382.2.1.26 Lesser-studied phyla Page 392.2.1.27 Amphibia – frogs, toads and newts Page 412.2.1.28 Marine and freshwater fish Page 422.2.1.29 Terrestrial Reptilia Page 452.2.1.30 Marine Reptilia – sea turtles Page 462.2.1.31 Birds Page 472.2.1.32 Terrestrial mammals Page 492.2.1.33 Marine mammals Page 502.2.2 Habitats Page 532.2.2.1 Arable field margins Page 552.2.2.2 Coastal sand dunes Page 562.2.2.3 Coastal vegetated shingle Page 572.2.2.4 Fragile sponge and anthozoan communities on subtidal rock Page 582.2.2.5 Hedgerows and boundary features Page 602.2.2.6 Intertidal boulders Page 612.2.2.7 Lowland dry acid grassland Page 622.2.2.8 Lowland heathland Page 632.2.2.9 Lowland meadows Page 642.2.2.10 Marine sands and gravels Page 652.2.2.11 Maritime cliff and slopes Page 672.2.2.12 Ponds Page 682.2.2.13 Reedbeds Page 692.2.2.14 Saline lagoons Page 702.2.2.15 Seagrass beds Page 712.2.2.16 Standing open water Page 732.2.2.17 Tide-swept channels Page 742.2.2.18 Wet woodland Page 753. Issues Affecting <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> Page 763.1 Nature Conservation Page 773.2 Agriculture Page 793.3 Fisheries Page 813.4 Built development Page 833.5 Transport and access Page 843.6 Air and terrestrial pollution Page 853.7 Marine pollution Page 863.8 Water resources Page 883.9 Climate change / sea level rise Page 893.10 Tourism Page 903.11 Economic development Page 914. Priorities for <strong>Biodiversity</strong> Conservation Page 934.1 Species Page 944.2 Habitats Page 955. Recommendations for Action Page 1156. Glossary Page 1177. Bibliography Page 119<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page

ISLES OF SCILLY BIODIVERSITYForeword by Philip Hygate Chief Executive <strong>of</strong> <strong>The</strong> Council for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.It gives me great pleasure to welcome the publication <strong>of</strong> the results <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> <strong>Audit</strong>.Written in conjunction with our colleagues at the <strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong> and funded by a grant from theAggregates Levy Sustainability Fund, the report is a comprehensive overview <strong>of</strong> the wide diversity <strong>of</strong> naturalhistory on the islands and some <strong>of</strong> the issues facing its conservation.<strong>The</strong> production <strong>of</strong> this report reflects the excellent relationships that exist between all the organisations and, inparticular, the burgeoning cooperation between the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s own <strong>Wildlife</strong> <strong>Trust</strong> and that <strong>of</strong> <strong>Cornwall</strong>. <strong>The</strong>work is a tribute to their willingness to share and collate information from a wide variety <strong>of</strong> sources.I sincerely hope the recommendations derived from this audit can be adopted and implemented as quicklyas is feasible. <strong>The</strong> conservation <strong>of</strong> the biodiversity <strong>of</strong> these islands is key to their uniqueness and contributessignificantly to the quality <strong>of</strong> life for the residents <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>Biodiversity</strong> has a strong influence inbringing much needed income to <strong>Scilly</strong> through well managed tourism and sustainable business practices.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page Grey seals. Photo: Rosemary Parslow

AcknowledgementsThis report was produced with support from a grant from Defra’s Aggregates LevySustainability Fund.<strong>The</strong> authors <strong>of</strong> this document wish to thank the following people for their input and constructive criticismduring the preparation <strong>of</strong> the report:Tim Allsop – St Martins Diving ServicesBeachwatch, Marine Conservation SocietyIan BeavisDominic Boothroyd - National Lobster Hatchery, PadstowKevan Cook – Zostera Survey Team and Natural EnglandDr Ken Collins – University <strong>of</strong> SouthamptonCoral Cay ConservationRaymond DennisJoana Doyle – <strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong>Craig Dryden – <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Council Planning OfficerDr Paul GaineyFrank GloysteinLouise Graham – <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> AONBMark and Susie Groves – Island Sea SafarisRen HathwayDouglas Herdson - National Marine AquariumAlfred Hicks – <strong>of</strong> the boat SeaquestDr Keith Hiscock – Marine Biological AssociationJan Loveridge - CWT Marine Strandings NetworkPr<strong>of</strong>essor Christine Maggs – Queens University, BelfastAmanda Martin – <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> MuseumDave Mawer, Senior Conservation Warden <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong>Cyril Nicholas – Natural England, <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Dr Malcolm NimmoJoe Pender – <strong>of</strong> the boat SapphireMark Pender – IoS Fishermen’s AssociationDr Bernard Picton – National Museums, Northern IrelandRebecca Seeley – Marine Biological AssociationDr Mark TelferAndrew TompsettDr Nick TregenzaStella Turk MBEDr Richard WarwickSteve Watt – <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Sea Fisheries Committee, IoS CouncilChris Wood - Seasearch<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page

ExecutiveSummary1 IntroductionObjectives <strong>of</strong> <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> <strong>Audit</strong>This publication represents the key first step in theprocess <strong>of</strong> producing <strong>Biodiversity</strong> Action Plansprocess for the variety <strong>of</strong> both species and habitatsthat make up the unique character <strong>of</strong> the islands. <strong>The</strong>objectives <strong>of</strong> this <strong>Biodiversity</strong> <strong>Audit</strong> are:· To assess the status and trends in biodiversity inthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>· To identify the main issues affecting biodiversity· To establish priorities for the conservation <strong>of</strong>biodiversity· To make recommendations for immediateaction to conserve and enhance the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’sbiodiversity2 <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s <strong>Biodiversity</strong>Analysis <strong>of</strong> Status and Trends to both Species andHabitatsThis report looks at all the key species groupings andrecognised BAP habitats, as listed in the UK BAP list,revised in 2007 and, for each, provides the followingkey headings for analysis:· Overview· Important Areas in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>· Conservation Importance· Trends and Issues affecting that species group orhabitat type.Overall Trends<strong>The</strong> extent and quality <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’sbiodiversity have been identified through this initialaudit and, in particular, the baseline for futurereporting <strong>of</strong> those issues identified and any changeis now in place. Both habitats and species are underthreat from climate change, habitat and environmentaldegradation.<strong>The</strong> trends are by no means all negative. <strong>The</strong> growthin public awareness <strong>of</strong> the unique habitats the islandshave to <strong>of</strong>fer has been very noticeable and the tourismindustry has worked hard to “sell” the environmentalbenefits to the visiting public. <strong>The</strong> development <strong>of</strong> the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong> and its growing liaisonwith the local community has seen wildlife habitatbeing restored – the heathland restoration work isparticularly encouraging. Agriculture on the islandsremains at a level that does not seriously affect thewider biodiversity and it continues to try and work intandem with environmental schemes and projects; anumber <strong>of</strong> the recommendations in this report look t<strong>of</strong>urther strengthen that relationshipOverall trends <strong>of</strong> both key species and habitats whereknown are recorded at Section 4 - <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>priority tables3 Issues Affecting <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s<strong>Biodiversity</strong>A number <strong>of</strong> issues that are deemed to have, orpotentially have, an effect on the biodiversity <strong>of</strong> the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are discussed at Section 3 <strong>of</strong> this report.<strong>The</strong> topics covered are:3.1 Nature Conservation3.2 Agriculture3.3 FisheriesWild flowers in arable fields. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page

3.4 Built Development3.5 Transport & Access3.6 Air and Terrestrial Pollution3.7 Marine Pollution3.8 Water Resources3.9 Climate Change & Sea Level Rise3.10 Tourism3.11 Economic DevelopmentThis section is intended to provide an overview<strong>of</strong> the causes, or potential causes, <strong>of</strong> change tothe biodiversity <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and will helpstimulate debate during the production <strong>of</strong> any actionand implementation plans or programmes <strong>of</strong> work forboth priority habitats and species.4 Priorities for <strong>Biodiversity</strong> Conservation<strong>The</strong> diversity <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s habitats andspecies groups is an important contributing factor<strong>of</strong> the archipelago’s unique character. This shouldbe enhanced, or at least maintained, at the currentlevels, so that future generations can enjoy the widerenvironmental, social and economic benefits suchbiodiversity can attract.However, in order to best achieve the conservationand enhancement <strong>of</strong> the islands’ biodiversity and toensure the best use <strong>of</strong> resources, priority species andhabitats have to be nominated.Priority species and habitats were selected usingcriteria laid out at Section 4; this was largely based onthe revised 2007 UK BAP List and included nationallyimportant species, those threatened locally by declineor rarity or those for which the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have asignificant percentage <strong>of</strong> the UK population.Priorities for biodiversity conservation include:· 293 Species· 18 HabitatsSome <strong>of</strong> these species and habitats are listed becausethere is a need for further research into their overallstatus, and their retention on the priority lists willdepend on any findings <strong>of</strong> that future research.5 Recommendations for ActionA number <strong>of</strong> key recommendations are provided,with further explanation at Section 5. <strong>The</strong>y needto be addressed as a matter <strong>of</strong> priority and theirimplementation will go a significant way towardsthe promotion and furtherance <strong>of</strong> biodiversityconservation in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Recommendation 1 – SurveyPromote and instigate survey work for those speciesand habitats on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> priority lists inSection 4 which need further research to establish theirlocal conservation needs and status.Recommendation 2 – Monitor and ResearchSupport and instigate monitoring and research <strong>of</strong>species and habitats on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> priority list.Recommendation 3 – Manage IoSWT land holdingsImplement, maintain and monitor the work plansoutlined in the Management Plans for <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>Wildlife</strong> <strong>Trust</strong> holdings produced in conjunction withthis report.Recommendation 4 – Marine Protected AreaWork towards the inclusion <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> ina South West or National Marine Protected Areanetwork.Recommendation 5 – Additional PlansConsider producing separate Action andImplementation Plans for those species and habitatsnot covered under recommendations 1 to 4.Recommendation 6 – Conservation Advisory GroupMaintain the Conservation Advisory Group for the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> as a focus for delivering biodiversityaction on <strong>Scilly</strong>.Spiny starfish Marthasterias glacialis amongst anemones. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page

1Introduction1.1 Objectives <strong>of</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s <strong>Biodiversity</strong> <strong>Audit</strong><strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s <strong>Biodiversity</strong> <strong>Audit</strong> is the firstimportant step in identifying the process <strong>of</strong> preservingthe variety <strong>of</strong> habitats and species that make up theunique character <strong>of</strong> the islands, both for now and thefuture.<strong>The</strong> objectives <strong>of</strong> this document are:· To assess the status and trends in biodiversity inthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>The</strong>re are good sources <strong>of</strong> information available forthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, in particular the Red Data Bookfor <strong>Cornwall</strong> and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (published in1997 and due for re-issue in <strong>2008</strong>), the annual <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> Review and the recently published NewNaturalist edition <strong>of</strong> <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> by RosemaryParslow. Discussion with experts and conservationorganisations has been crucial in drawing togetherinformation for this <strong>Biodiversity</strong> <strong>Audit</strong>. Additionally,there are the numerous recording groups andindividuals who diligently record; many are members<strong>of</strong> the influential <strong>Cornwall</strong> and <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Federation <strong>of</strong> Biological Recorders (CISFBR).All <strong>of</strong> these sources have been used in combinationwith information published nationally, includingaction plans and regionally in <strong>The</strong> <strong>Biodiversity</strong> <strong>of</strong> theSouth West, to provide an up to date picture <strong>of</strong> thecurrent status <strong>of</strong> habitats and species throughout theislands and, where possible, identify trends in theirstrength and distribution.· To identify the main issues affecting biodiversityWide consultation has been carried out to establish themain issues that affect biodiversity in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>,and how those issues influence habitats and species.· To establish priorities for the conservation <strong>of</strong>biodiversityUsing the wide range <strong>of</strong> information available,priorities have been established for the conservation <strong>of</strong>habitats and species <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.· To make recommendations for action to conserveand enhance the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s biodiversityAt national and regional levels, it has provedeffective to produce specific habitat or species actionplans. It would clearly be unrealistic to produceseparate plans for all the priorities identified inthis report and a different approach has beentaken. Six recommendations have been developedwhich encompass all the identified priorities. <strong>The</strong>serecommendations will provide the starting point forthe next stage in the <strong>Biodiversity</strong> Action Planningprocess which should be the formation <strong>of</strong> workinggroups aimed at taking each recommendationforward. Implementation can be achieved througha variety <strong>of</strong> processes including precisely targetedaction plans, broader generic actions or the inclusion<strong>of</strong> biodiversity priorities in existing or plannedprogrammes <strong>of</strong> work.1.2 Origins <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> <strong>Audit</strong><strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> <strong>Audit</strong> has its originsin the Rio Earth Summit which took place in June1992. This agreement included the “Convention onBiological Diversity” ratified by the UK Governmentwhich in turn led to the UK <strong>Biodiversity</strong> Action Plan in1994 and <strong>Biodiversity</strong>: <strong>The</strong> UK Steering Group Reportin 1995.<strong>The</strong> South West Regional <strong>Biodiversity</strong> <strong>Audit</strong>Directly resulting from the UK legislation, the SouthWest formed the first regional initiative and theproduction <strong>of</strong> the South West Regional <strong>Biodiversity</strong><strong>Audit</strong> in February 1996. It described the key speciesand habitats to be found in the region and had backingfrom the seven <strong>Wildlife</strong> <strong>Trust</strong>s, RSPB, English Nature(now Natural England), the Environment Agency andSeaweeds in the intertidal zone. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page

the South West Regional Planning Conference.Based on this cooperation, each county has developedits individual biodiversity audit with <strong>Cornwall</strong>publishing theirs in 1997.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Biodiversity</strong> <strong>Audit</strong>It had become apparent that the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> had beenleft behind in the audit process. Despite having highbiodiversity that embraced a unique set <strong>of</strong> species,there were never enough resources to carry out thebasic research. <strong>The</strong> development <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>Wildlife</strong> <strong>Trust</strong> (IoSWT) and the production <strong>of</strong> the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> AONB Management Plan became the catalystfor the full audit.Original management plans for the IoSWT holdingswere produced in 2002 and this along with closercooperation between the <strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong> andthe IoSWT in 2007 led to a successful grant applicationthrough the Aggregates Levy Sustainability Fund(ALSF) for funding to produce this audit.1.3 What is <strong>Biodiversity</strong>?<strong>Biodiversity</strong> describes the “variety <strong>of</strong> life”. Species andhabitats are lost and new ones develop through theprocess <strong>of</strong> evolution. <strong>The</strong> present rate <strong>of</strong> change, thethreat <strong>of</strong> climate change and the impact <strong>of</strong> humans hasmeant evolution requires direct intervention; we needto manage biodiversity in a sustainable way.Article 2 <strong>of</strong> the <strong>Biodiversity</strong> Convention definesbiodiversity as:“<strong>The</strong> variability among living organisms from allsources including, amongst others, terrestrial, marineand other aquatic ecosystems and the ecologicalcomplexes <strong>of</strong> which they are part; this includesdiversity within species, between species and <strong>of</strong>ecosystems.”Put more simply this means the “variety <strong>of</strong> life”encompassing all the species and their multitude <strong>of</strong>different habitats.Evolution<strong>Biodiversity</strong> is continually changing; many speciesand habitats are being lost annually. During the 20thcentury the UK lost over 100 species and this trend hascontinued in the first few years <strong>of</strong> the 21st century.However, as our environment alters, new habitatsevolve and existing species adapt to survive. <strong>The</strong>ycreate new sub-species and, in some instances, newspecies appear. Evolution is never static; species willgo extinct naturally and humans will continue to havean impact on the environment.Extinction<strong>The</strong> world is losing species and habitat at anaccelerated rate as a result <strong>of</strong> human activity.Although species evolve to survive in changingenvironments, if the rate <strong>of</strong> change is too fast thenthey will not adapt quickly enough to maintain theircompetitive advantages.In the UK, populations <strong>of</strong> many species are decliningat an alarming rate; this has resulted in a majoroverhaul <strong>of</strong> the <strong>Biodiversity</strong> Action Plan (BAP) priorityspecies in 2007 with nearly six hundred more speciesbeing added to the list.Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 10

2<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>Biodiversity</strong><strong>The</strong> biodiversity <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> reflects theirunique position at the extreme south west <strong>of</strong> theUnited Kingdom and the associated maritimeinfluences. Situated within the Gulf Stream, the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> have a climate allowing a breadth <strong>of</strong> floratending towards the tropical. This is interspersedwith small wall and hedge enclosed field systemsused for both bulb and spring flower productionand livestock grazing. As islands their maritimebiodiversity is very important as is the propensity tohave isolated development <strong>of</strong> sub-species.2.1 Biological Records and Sources <strong>of</strong> Information<strong>The</strong> Environmental Records Centre for <strong>Cornwall</strong> andthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (ERCCIS) holds an extensive number<strong>of</strong> environmental and geological records for bothmainland <strong>Cornwall</strong> and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. Historically,species information has been collected by dedicatedindividuals or recording groups. Unlike <strong>Cornwall</strong>,there has been little habitat mapping, but recent workto create management plans for all <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>Wildlife</strong> <strong>Trust</strong> land holdings has made significantstrides in rectifying this for the terrestrial environment.<strong>The</strong> species records and recent habitat mapping,coupled with invaluable contributions from NaturalEngland, <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Council and the Duchy <strong>of</strong><strong>Cornwall</strong>, have allowed an assessment <strong>of</strong> the statusand trends <strong>of</strong> biodiversity on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>,relating to habitats and species.<strong>The</strong> United Kingdom is considered one <strong>of</strong> the mostcomprehensively studied regions in the world interms <strong>of</strong> species present and habitat cover. Despitethis there are still significant gaps in the knowledgebase; there is still uncertainty as to the number <strong>of</strong>species present, their population sizes and the levels<strong>of</strong> decline each species can tolerate. Additionally,there is considerable imbalance to that knowledgebase; there is comprehensive data with respect t<strong>of</strong>lowering plants, mammals, birds and the higherlevels <strong>of</strong> invertebrates (butterflies and moths). <strong>The</strong>less glamorous, but equally important, groups suchas fungi, lower order plants and most invertebratesare not as well documented, but with study continueto present new species for the UK. In terms <strong>of</strong> speciesnumbers these groups contribute more to overallbiodiversity, and knowledge <strong>of</strong> where they sit in thewider picture is fundamental to the conservation <strong>of</strong> thehigher forms <strong>of</strong> species.Species Experts<strong>The</strong>re already exists a wide understanding <strong>of</strong> thewildlife <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> through the dedicated work<strong>of</strong> both recording groups and individuals. Particularstrengths are birds (<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Bird Group), bats(<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Bat Group) and higher plants (CISFBR).Many <strong>of</strong> the groups and individuals contributed tothe Red Data Book for <strong>Cornwall</strong> and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>in 1997 and are updating that publication for re-issuein <strong>2008</strong>. All these groups and individuals have beenconsulted during the publication <strong>of</strong> this audit.Habitat MappingUnlike their close neighbour <strong>Cornwall</strong>, the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> have not benefited from a systematic terrestrialhabitat mapping project. <strong>The</strong> production <strong>of</strong> theoriginal management plans for IoSWT land had somehabitat maps, but these plans did not contain detailfor other land holdings, particularly that held by theDuchy <strong>of</strong> <strong>Cornwall</strong> and Tresco, privately owned bythe Dorien-Smith family.As a condition <strong>of</strong> the ALSF grant a repeat <strong>of</strong> themapping <strong>of</strong> all the IoSWT land holdings wasagreed. This was a key part <strong>of</strong> the updating <strong>of</strong> theJewel anemone. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 11

management plans for these holdings. Whilst thismapping will cover 40% <strong>of</strong> the islands above the MeanHigh Water Level, there are still important areas thatremain outside <strong>of</strong> this work, particularly intertidalareas.Part <strong>of</strong> one <strong>of</strong> the main recommendations <strong>of</strong> this auditis for systematic habitat mapping <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>;without this there are elements <strong>of</strong> a biodiversity auditthat remain inconclusive.Environmental Records Centre for <strong>Cornwall</strong> and the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (ERCCIS)<strong>The</strong> Environmental Records Centre for <strong>Cornwall</strong>and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (ERCCIS) is the focus for allbiological and geological records for the islands. <strong>The</strong>rehas been a significant effort to capture all the availabledata for all species to inform this audit. <strong>The</strong> RecordsCentre is the focus for the re-issue <strong>of</strong> the Red DataBook for <strong>Cornwall</strong> and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and has adedicated staff responsible for the collection, collationand dissemination <strong>of</strong> environmental data for the area.Information sources used in the production <strong>of</strong> this<strong>Biodiversity</strong> <strong>Audit</strong>Data and information form a key element <strong>of</strong> the<strong>Biodiversity</strong> Action Planning process. <strong>The</strong> data neededto compile this <strong>Biodiversity</strong> <strong>Audit</strong> have come from awide range <strong>of</strong> sources:· ERCCIS· Local recorders and recording groups· Statutory and voluntary agencies· <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong>· Scientists / species experts2.2 Summary Statements: Status and Trends2.2.1 Species<strong>The</strong> following species overviews provide a summary<strong>of</strong> the status <strong>of</strong> the different taxonomic groupsoccurring on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Overviews include:· An introduction to the species group· An indication <strong>of</strong> the conservation importance <strong>of</strong>the species group· <strong>The</strong> main trends and issues relating to the groupin the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>The</strong> groupings are broken down by taxonomic groupas follows: Marine algae2.2.1.2 Stoneworts2.2.1.3 Fungi2.2.1.4 Lichens2.2.1.5 Mosses and Liverworts2.2.1.6 Horsetails, Ferns and Flowering Plants2.2.1.7 to Invertebrates (including Insects) Amphibians2.2.1.28 Fish2.2.1.29 and Reptiles2.2.1.31 Birds2.2.1.32 and Mammals<strong>The</strong> species overviews act as a baseline for furtherwork, in particular the production <strong>of</strong> individualspecies action plans and will be instrumental ininforming the wider landscape management <strong>of</strong> keyhabitats.Rocks <strong>of</strong>f White Island. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 12 Marine algae - seaweedsOverviewAlgae are simple, non-flowering plants that reproduceby spores. In the marine environment there aresingle celled algae (phytoplankton) and multicellularmacroalgae or seaweeds. Like all plants they requirelight for photosynthesis; their range below the lowwater mark is determined by the amount <strong>of</strong> lightthat is able to penetrate the water. In the clear waters<strong>of</strong> <strong>Scilly</strong>, where light penetration is very good,macroalgae is found down to depths <strong>of</strong> 45m or so.Generally, the green algae (Chlorophyta) are foundonly in shallow water or high up the shore, brownalgae (Phaeophyta) occurs in slightly deeper water andred algae (Rhodophyta) are the best at coping with lowlevels <strong>of</strong> light so occur at the deepest depths.In <strong>Scilly</strong> algae have long been important to humanresidents, particularly brown algae which were burntin kelp pits until the early 19th century to producesoda ash for the glass-making industry. Algae growon hard substrates and are abundant in the intertidaland shallow subtidal areas <strong>of</strong> <strong>Scilly</strong>. Some speciesare annual, growing and then dying back each year.Large amounts <strong>of</strong> dead algae are washed up onbeaches around the islands, particularly after storms.<strong>The</strong>se piles <strong>of</strong> decaying organic material supportcommunities <strong>of</strong> decomposers and supply nutrients tobeach dwelling organisms.<strong>The</strong> most diverse group <strong>of</strong> algae is the red algae whichincludes calcareous species that encrust many <strong>of</strong> therock surfaces. Approximately 400 species <strong>of</strong> red algaeoccur in <strong>Cornwall</strong>, most <strong>of</strong> which are present in <strong>Scilly</strong>(Parslow, 2007). <strong>The</strong> algal communities <strong>of</strong> <strong>Scilly</strong> havebeen noted for their high diversity and the presence <strong>of</strong>many rare species (Barne et al, 1996).Important AreasSeaweeds occur on all rocky shores around <strong>Scilly</strong>and on hard substrate down to over 30m. Larger,more frondose plants such as egg wrack Ascophyllumnodosum and sugar kelp Saccharina latissima are prolificin areas with more shelter. On exposed shores theFucoids (wracks) are sparse and Fucus vesiculosus isstunted. On some rock faces there is no vegetationuntil the Laminaria zone, where there is <strong>of</strong>ten welldeveloped Alaria esculenta (Harvey 1969). <strong>The</strong>re aredense stands <strong>of</strong> Laminaria ochroleuca, a rare southwestspecies (Warwick et al, 2003).<strong>The</strong> kelps provide a three dimensional habitat forother species such as wrasse and urchins. <strong>The</strong>ysupport epiphytic and epizootic species such asbryozoans and grazers such as blue rayed limpetsHelcion pellucidum. <strong>The</strong> calcareous pink seaweedCorallina <strong>of</strong>ficinalis is abundant between mid tide andlow water, supporting a diverse faunal communityincluding isopods.Conservation Importance<strong>The</strong> marine algal communities <strong>of</strong> <strong>Scilly</strong> are importantbecause <strong>of</strong> their high species diversity (Barne etal, 1996). <strong>Scilly</strong> has recently been nominated as anImportant Plant Area for marine algae (Brodie etal, 2007). <strong>The</strong>re are two BAP species and a number<strong>of</strong> nationally rare and scarce species, particularlyRhodophyta.In areas where the sand is mixed with gravel, pebblesand cobbles between the islands, communitiesinclude nationally rare species such as the redseaweeds Cruoria cruoriaeformis (a BAP species),Gelidiella calcicola and Schmitzia hiscockiana. <strong>The</strong> JointNature Conservation Committee identified Schmitziahiscockiana as an important species in a review <strong>of</strong> thearea (Barne et al, 1996). It is at the extreme southernend <strong>of</strong> its range in <strong>Scilly</strong> and it is not found again untilmuch further north, in Wales (Maggs and Guiry, 1985).Climate change could be expected to result in a retreatnorthwards (Maggs, pers. comm.).Dermocorynus montagnei is another BAP red seaweedoccurring in <strong>Scilly</strong> which is internationally threatenedand rare. It has a very small known distribution,from Brittany in France, to western Scotland andis associated with beds <strong>of</strong> mobile substrata that areunder various threats such as aggregate extraction. Italso occurs in seagrass beds.Bornetia secundiflora is a red alga believed to be extremelyrare in the UK which has been collected only in <strong>Scilly</strong>(and at one site in the west <strong>of</strong> Ireland). Myriogrammeminuta is also only commonly found in <strong>Scilly</strong>.Other nationally rare red seaweeds in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>areAtractophora hypnoidesCryptonemia lomationGigartina pistillataHalymenia latifoliaPterosiphonia pennataRhodophysema georgei (which lives on Zostera)Rhodymenia delicatulaSchmitzia neapolitanaNationally Gelidium sesquipedale (synonym G. corneum)is only frequent in <strong>Scilly</strong> and is a southern speciescommon in Iberia. Pterosiphonia pennata and Gracilariabursa-pastoris likewise are southern species <strong>of</strong> redseaweed which are found there (Brodie et al, 2007).Cryptonemia lomation is extremely rare in the UK, andprobably confined to <strong>Scilly</strong> (it is a southern speciesalso found in the Mediterranean). Gigartina pistillatais another southern species reaching its limit insouthwest England (C.Maggs, pers. comm.).Carpomitra costata and Desmarestia dresnayi arenationally scarce brown seaweeds (Hiscock, 1984).C.costata is a southern species that lives subtidally toover 30m.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 13

Trends and IssuesHabitat LossLoss <strong>of</strong> seagrass in the past represents habitat loss formany species <strong>of</strong> algae. [See Dermocorynus montagneiabove]Climate ChangeIn Brittany and Norway the brown seaweedSaccharina latissima has disappeared from somesites and this is thought to be a response to risingsea temperatures due to climate change (Moy andStålnacke, 2007). This species is abundant in <strong>Scilly</strong> butshould be monitored.Invasive Species<strong>The</strong> invasive brown macroalgae, japweed Sargassummuticum was first recorded in <strong>Scilly</strong> in 1991 (Fowler,1992) and now has a firm foothold in the environment(Cook et al, 2001).Pikea californica is a non-native species <strong>of</strong> red seaweedwhich was first recorded in <strong>Scilly</strong> in 1983 (Hiscock,1983) and is widespread throughout the surge zonein <strong>Scilly</strong> (Maggs and Guiry, 1986). It was thought tohave been introduced during World War II on boatsfrom its native East coast <strong>of</strong> North America. <strong>Scilly</strong> isthe only area in the UK where this species is recorded.Asparagopsis armata is another alien red alga present in<strong>Scilly</strong> which originates from Australia (Horridge, 1951).Thongweed Himanthalia elongata and other algae. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 14 Charophytes - StonewortsOverviewStoneworts are a small group <strong>of</strong> terrestrial orfreshwater simple, green algae, <strong>of</strong> the familyCharophyta. <strong>The</strong>y inhabit aquatic habitats, such asfresh and brackish pools and wetlands. Stonewortshave a requirement for calcium carbonate whichaccumulates on the surface <strong>of</strong> the plant giving thecharacteristically hard coating. Although usuallyassociated with calcareous waters, stonewortsare also found in coastal pools including oneswith muddy substrates, consequently the greatestconcentration and diversity <strong>of</strong> these species are foundon the coastal sand dunes and in pools situated onbasic soils.Important Areas<strong>The</strong> only site in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> where stonewortshave been recorded is the Abbey Pool on Tresco. <strong>The</strong>reis some confusion as to which species was recorded.Further investigation is needed.Conservation Importance<strong>The</strong>re are no species <strong>of</strong> particular conservationimportance recorded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Trends and IssuesResearchMore research is required in order to fully establishwhether there are any species <strong>of</strong> stoneworts in the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong>. Nick Stewart, a Chara specialist, suggests theAbbey Pool should be investigated as there could be arare Chara there.Inonotus hispidus on Tresco. Photo: Jean Paton2.2.1.3 Fungi - Mushrooms andToadstoolsOverviewMushrooms and toadstools are collectively knownas fungi, which are a kingdom in themselves, beingneither plants or animals. <strong>The</strong>re is a range <strong>of</strong> fungi, butthe more familiar mushrooms and toadstools. can stillgrow in a number <strong>of</strong> forms – as a mat <strong>of</strong> fungal roots,or hyphae, in the soil, from which the characteristicfruiting bodies arise; as parasites on live plants; orbreaking down the organic matter on dead or animaldroppings.Habitats include woods, grasslands, sand dunes anddomestic gardens. Fungi require similar conditions t<strong>of</strong>lowering plants. <strong>The</strong>refore, if areas are managed wellfor plants involving grazing, and lack <strong>of</strong> fertilisers,fungal diversity will also tend to be maintained.Important Areas<strong>The</strong>re are no areas known to be <strong>of</strong> particularimportance for fungi in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, butthat does not mean that there are none. Species <strong>of</strong>national conservation importance are present in<strong>Scilly</strong> and the significance <strong>of</strong> their locations needs tobe considered.Conservation Importance<strong>The</strong>re are two species on the BAP priority list:Elegant Earthstar Geastrum elegansCoral Tooth Hericium coralloidesTrends and IssuesResearchIt would be useful if an expert review <strong>of</strong> themushrooms and toadstools <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> werecarried out. This is a group that is only moderatelywell understood on the mainland <strong>of</strong> <strong>Cornwall</strong> andthere appears to have been very little fieldwork carriedout in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 15 LichensOverviewLichens are lower plants formed from associations <strong>of</strong>certain fungal species with a green alga or bacterium.Lichens may be encrusting, leafy or even shrubby,depending on the species. <strong>The</strong>y vary widely incolouration including shades <strong>of</strong> orange, green, greyand black.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> support a particularly rich anddiverse lichen community, with some 665 specieshaving been recorded since 1970. This is largelyattributable to the mild oceanic climate and clean air,many lichens being sensitive to atmospheric pollution.A number are associated with maritime cliff and slope,and with supralittoral zones.Important AreasLichens <strong>of</strong> significant conservation concern are foundon all the main islands. <strong>The</strong> majority are coastal sites,including heathland and maritime grassland sitesand their associated rocky habitats. Some lichens areassociated with a few individual trees.Conservation Importance<strong>The</strong>re are 8 species on the BAP priority list:Acarospora subrufulaBacidia incomptaCryptolechia carneoluteaHeterodermia leucomela Ciliate strap-lichenOpegrapha prosodeaPseudocyphellaria aurataTeloschistes flavicans Golden Hair-lichenWadeana dendrographa<strong>The</strong>re are also nine RDB lichens:Bacidia assulataBuellia abstractaCatillaria subviridisHeterodermia propagulifera Coralloid Rosette-lichenLecanora strobilinaLecidia sarcogynoidesLecidella viridansRamalina chondrinaUsnea subscabrosa<strong>The</strong>re are 4 near threatened species and 16 nationallyscarce species.Trends and IssuesResearch<strong>The</strong> localities <strong>of</strong> many <strong>of</strong> these species are knowndue to research by Bryan Edwards and others, buta comprehensive survey <strong>of</strong> all the BAP, RDB andnear threatened species is needed. For example, thegilt-edged lichen Pseudocyphellaria aurata, whichhas not been recorded since 1967, was rediscoveredrecently, but on White Island rather than formerlocations.ManagementCertain species growing in heathland are vulnerableto uncontrolled fires. <strong>The</strong> invasion <strong>of</strong> heathlandby gorse and lack <strong>of</strong> grazing threaten terricolouslichens.CollectionAttractive species such as golden hair-lichenTeloschistes flavicans are vulnerable to collection.Golden hair-lichen Teloschistes flavicans amongst other species on granite. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 16 Bryophytes - Mosses andLiverwortsOverviewMosses and liverworts are lower plants, collectivelycalled the bryophytes, many <strong>of</strong> which are small,inconspicuous and difficult to identify. Mosses canbe divided into the ‘true’ mosses, peat or bog mosses(Sphagnum spp) and the granite or rock mosses.Liverworts are stem-less, leaf-like organisms.Habitats where they are found include most siteswhere you would expect to find vascular plants.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is small and isolated with limitedgeological variation. Nevertheless, the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>has a diversity <strong>of</strong> bryophytes largely attributableto the mild, oceanic climate. Approximately 159species <strong>of</strong> moss (22% <strong>of</strong> the total species known in theBritish <strong>Isles</strong>) and 63 liverworts (again, 22%) have beenrecorded here.Some <strong>of</strong> the species on the islands are alien speciesthat have arrived with introduced plants. A number <strong>of</strong>the RDB species fall into this category.Important AreasBryophytes are found in a wide range <strong>of</strong> habitats in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> from the maritime coasts and heathlands,through the arable land to individual trees in parksand gardens.Conservation Importance<strong>The</strong>re are two species on the BAP priority list:Sphaerocarpos texanusTortula wilsoniiTexas balloonwortWilson`s pottiaWilson’s pottia has not been recorded for over half acentury.<strong>The</strong>re are a further 11 RDB species, 4 <strong>of</strong> which havebeen introduced. <strong>The</strong>re are further 22 Nationallyscarce species.<strong>The</strong> RDB species are the mosses:Tortula solmsiiTortula rhizophyllaiTortula wilsonii (pre 1950)Eriopus apiculatus (introduced)Sematophyllum substrumulosum;and the liverworts:Telaranea murphyae (introduced)Cephaloziella turneriLophocolea bispinosa (introduced)Lophocolea semiteres (introduced)Gongylanthus ericetorumFossombronia pusilla var maritimaSphaerocarpos texanusRiccia crystallina (introduced)Trends and IssuesHabitat Loss<strong>The</strong> reduction in heathland grazing has had an adverseeffect on certain heathland structures, which in somecases might have a knock-on effect on bryophytesspecies.ManagementUncontrolled heathland fires can have an adverseeffect on the survival <strong>of</strong> certain species.TourismIncreased visitor numbers have led to more trampling<strong>of</strong> certain areas and an increase in uncontrolled fires.Alien SpeciesCertain species have been - or are assumed to havebeen - introduced to the islands with horticulturalplants. Species such as Lophocolea semiteres haveoverwhelmed certain micro-habitats <strong>of</strong> the nativebryophytes.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 17 Horsetails, ferns andflowering plantsOverview<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have a rich flora <strong>of</strong> ferns andflowering plants (which include herbs, shrubs, trees,grasses, sedges and their relatives). Only one species<strong>of</strong> horsetail, Equisetum arvense is found in <strong>Scilly</strong>, andthat only rarely. Plants are found in a wide range <strong>of</strong>habitats ranging from inland grasslands, wetlandsand coastal habitats to those <strong>of</strong> very exposed cliffs androcky islets. A number <strong>of</strong> species found in <strong>Scilly</strong> haveMediterranean and Lusitanian associations and are atthe northern limit <strong>of</strong> their distribution. Some species<strong>of</strong> plants are unique to <strong>Scilly</strong> and others, common insimilar habitats in <strong>Cornwall</strong>, are absent.Important AreasSome sites in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are exceptionallyrich in ferns and flowering plants. <strong>The</strong>se includeheathlands on Wingletang, Salakee and PorthellickDowns, dune grassland, the saline pool on Bryherand the uninhabited islands <strong>of</strong> Samson, Annet, GreatGanilly and Teän. <strong>The</strong> coastal habitats are particularlyimportant on all the islands. Inland the wetlands <strong>of</strong>Higher and Lower Moors and the lakes on Tresco areall significant plant habitats.Conservation ImportanceShore dock Rumex rupestris is listed on Annex II <strong>of</strong> theEU Habitats Directive.<strong>The</strong> presence <strong>of</strong> shore dock is one <strong>of</strong> the reasons forSAC designation <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong> shore dockappears to be in decline and is now only known fromsites on four islands in <strong>Scilly</strong>.National BAP priority species are:Chamomile Chamaemelum nobileTubular water-dropwort Oenanthe fistulosa.Shore dock Rumex rupestrisPrickly saltwort Salsola kali kaliShepherd’s needle Scandix pecten-venerisSmall-flowered catchfly Silene gallicaTrends and IssuesHabitat lossAny loss <strong>of</strong> habitat especially <strong>of</strong> unimprovedgrassland, wetlands, and coastal habitats has animpact on the biodiversity <strong>of</strong> the higher plantcommunities. Although the areas may be quite small,in the context <strong>of</strong> the limited land area on the inhabitedislands, the draining <strong>of</strong> any wetland or spraying <strong>of</strong> afew hectares <strong>of</strong> coastal grassland for example can havea deleterious effect.ManagementLack <strong>of</strong> management, changes in managementand inappropriate management all have effects onvegetation.Changes in agriculture and horticulture can besignificant on plant communities. For example thedownturn in growing winter-flowering narcissus hasled to the loss <strong>of</strong> species-rich communities <strong>of</strong> arableplants (weeds). Many fields formerly used for bulbgrowinghave been put down to grass or alternativearable crops.Abstraction from wetlands and the streams haveresulted in loss <strong>of</strong> plant species. Higher and LowerMoors are much drier than they used to be. A smallarea <strong>of</strong> acid bog has disappeared and with it the bogcotton Eriophorum angustifolium and other unusualplants. Cornish moneywort Sibthorpia europaea has alsogone from all but one <strong>of</strong> its former sites.PollutionUse <strong>of</strong> fertilisers and herbicides can all be detrimentalto native plant communities.CollectionOne rare fern has been collected in the past. <strong>The</strong>re areat least two fern species in <strong>Scilly</strong> that may be attractiveto collectors.MonitoringBSBI recorder, Rosemary Parslow monitors the flora <strong>of</strong><strong>Scilly</strong> including most BAP plant species and conductsongoing monitoring projects on the arable speciesand on Ophioglossum taxa. IoSWT monitor shore dockwhen these sites are visited.Species found only in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are leastadderstongue fern Ophioglossum lusitanicum, orangebirdsfoot Ornithopus pinnatus, dwarf pansy Violakitabeliana.Species endemic to <strong>Scilly</strong> and <strong>Cornwall</strong> includewestern fumitory Fumaria occidentale and Babington’sleek Allium ampeloprasum var babingtonii.Dwarf pansy Viola kitabeliana is endemic to the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 18 Porifera - spongesOverviewSponges are the least complex <strong>of</strong> all multicellularanimals; these simple colonial animals vary in formand colour. <strong>The</strong>y are sessile suspension feeders withspecialised cells called choanocytes which drive waterthrough their canals and chambers. <strong>The</strong>y filter largevolumes <strong>of</strong> water, removing oxygen, fine particles andplankton.Species identification can be difficult and is <strong>of</strong>ten onlypossible by microscopic examination <strong>of</strong> spicules (smallpieces <strong>of</strong> silica or calcium carbonate which reinforcethe sponges’ structure). Sponges can be found fromthe intertidal zone to deep water habitats. <strong>The</strong>y growon a range <strong>of</strong> substrates including rocks, shells andseaweeds. <strong>The</strong>ir form may be erect, encrusting orirregular in shape but they are characterised by thepresence <strong>of</strong> many small water intake holes and fewlarger water outlet holes.Important AreasMany <strong>of</strong> the rocky reefs in <strong>Scilly</strong> support rich spongecommunities. Sponges also inhabit the underside <strong>of</strong>boulders on the less exposed rocky shores. <strong>The</strong> circalittoralsponge communities on the sheltered coast <strong>of</strong>St Mary’s, for example are <strong>of</strong> very high interest andextremely diverse (Fowler and Pilley, 1992)Conservation Importance<strong>Scilly</strong> is particularly rich in sponge life (Parslow, 2007),especially on the circa-littoral bedrock (40-65m depth)where there are very high densities <strong>of</strong> infrequentlyrecorded erect sponges (Munro and Nunney, 1998).this is also a southern species and is nationally scarce.Tethyspira spinosa, a nationally scarce species typical<strong>of</strong> exposed sites has been recorded as present in <strong>Scilly</strong>and, along with Axinella damicornis, has been identifiedin the Natural Area Pr<strong>of</strong>ile (Natural England) as apriority species for conservation. <strong>The</strong> nationally scarcespecies Homaxinella subdola and Crella rosea are presentin the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (Ulster Museum, 2007).Trends and IssuesResearchSponges are recorded during annual Seasearchexpeditions to the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, however due to thedifficulties <strong>of</strong> identification in the field not all spongesare recorded at species level.Specimens <strong>of</strong> many sponges from <strong>Scilly</strong> have beenadded to the Ulster Museum’s sponge collectionrecently, following survey work by Bernard Picton.DiseaseAlthough there are no reports <strong>of</strong> sponge disease in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, such reports have increased dramaticallyin recent years with sponge populations decimatedthroughout the Mediterranean and Caribbean(Webster, 2007).FishingSponges can be easily damaged by mechanical action,particularly branching or erect forms. Scallop dredgingand trawling can rapidly destroy sponge colonies.PollutionOil spills could be very deleterious to spongecommunities, particularly in intertidal areas.Although none <strong>of</strong> the sponges in <strong>Scilly</strong> are BAPspecies the area is rich in sponge life are classifiedunder the BAP habitats ‘fragile sponge and anthozoancommunities on subtidal rock habitats’ and ‘intertidalboulders’. <strong>The</strong>re are several nationally rare and scarcespecies present but it is the diversity and richness<strong>of</strong> the sponge communities which is <strong>of</strong> greatestconservation importance in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Munro and Nunney (1998) found Axinellainfundibuliformis a nationally rare species living incircalittoral areas on western shores in <strong>Scilly</strong>. In 2005Seasearch surveyors found the nationally scarcesponge Axinella damicornis at four sites, includingone site where it was common. It typically lives onrock faces with moderate wave action below 20mand although it is classified as nationally scarce it isactually quite a common species (Picton, pers. comm.).<strong>The</strong> nationally rare sponge Desmacidon fruticosuminhabits the same type <strong>of</strong> surfaces and prefers oceanicwater below depths <strong>of</strong> about 25m.Seasearch surveys during 2007 found Adreusfascicularis at Peter’s Rock and North Chapel Rock;A yellow branching sponge. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 19 Cnidaria - sea anemones,jellyfish, corals and relativesOverviewThis group <strong>of</strong> predominantly s<strong>of</strong>t bodied, simpleanimals is characterised by the presence <strong>of</strong> stingingcells or nematocysts. <strong>The</strong>y use these nematocystsand their tentacles to catch prey from the watercolumn. Sea anemones, jellyfish, hydroids, sea pensand corals are all members <strong>of</strong> the phylum Cnidaria.Many cnidarians have both planktonic and benthiclifestages, while some, such as most jellyfish, are solelyplanktonic.Benthic cnidarians are sessile and may be attached toa range <strong>of</strong> substrates including rock, seaweed, shells,wreckage and in s<strong>of</strong>t sediments. Members <strong>of</strong> thisgroup are important to the recreational dive industryas they are some <strong>of</strong> the most colourful and attractivecomponents <strong>of</strong> the underwater landscape. Hydroidsare feathery, fairly inconspicuous members <strong>of</strong> thisgroup which <strong>of</strong>ten dominate rocky areas and areheavily grazed by seaslugs.Important AreasOn rocky shores beadlet anemones, Actinia equinaare very common, especially on vertical rock faces atmid-tide level, while elegant anemones Sagartia elegansmay form local aggregations in pools and underoverhangs. Hard substrate in these areas precludesdevelopment <strong>of</strong> a burrowing fauna (Harvey, 1969)but on the sand flats burrowing anemones may occurwhere sediment is stable. Sea pens also grow in s<strong>of</strong>tsediment. Planktonic cnidarians such as jellyfish maybe encountered anywhere in the waters around <strong>Scilly</strong>and are sometimes found dead on beaches where windand currents have stranded them.Pink sea fans Eunicella verrucosa occur in areas withpredictable currents, though never in great numbers in<strong>Scilly</strong>. Important sites include East Trinity, Gugh Reef,Hoe Point, Hard Lewis Rock, Darrity’s Hole, NorthChapel Rock, Flat ledge, Plympton and Hather wreck(Seasearch 2006). Sea fan anemones Amphianthusdohrnii have been found on pink sea fans at NorthChapel Rock and Flat ledge.Conservation Importance<strong>The</strong> Anthozoa (corals and anemones) are part <strong>of</strong>the BAP habitat ‘fragile sponge and Anthozoancommunities on subtidal rock habitats’.<strong>The</strong> pink sea fan Eunicella verrucosa is nationally scarceand is a BAP species; furthermore it is host to anotherBAP species, the sea fan anemone Amphianthus dohrniiwhich is nationally rare. Sea fan anemones are foundin low numbers in <strong>Scilly</strong> (Seasearch, 2004). Pink seafans are also host to the sea fan nudibranch Tritonianilsodneri which is nationally scarce and lays its eggsAn anemone Sagartia sp. Photo: Malcolm Nimmoon pink sea fans. Pink sea fans are protected underSchedule 5 <strong>of</strong> the <strong>Wildlife</strong> and Countryside Act 1981.Due to their branching structure sea fans are thoughtto provide important attachment sites for the egg cases<strong>of</strong> some elasmobranchs.Pink sea fans occur in forests in <strong>Scilly</strong> although theseare not as dense as those around mainland <strong>Cornwall</strong>,possibly because the exposure is greater in <strong>Scilly</strong>(Seasearch, 2004). Colonies are also generally smallcompared to mainland sea fans. In <strong>Scilly</strong> the whitecolour morph is predominant, unlike <strong>Cornwall</strong> wherepink individuals are much more common. <strong>The</strong> whitecolour morph occurs in other areas such as Gibraltarand the west coast <strong>of</strong> Ireland. Populations <strong>of</strong> pink andwhite sea fans may be quite separate genetically (C.Wood, pers. comm. and B.Picton, pers. comm.)Scarlet and gold cup coral Balanophyllia regia, anationally scarce species has been recorded at two sitesand the nationally rare sunset cup coral Leptopsammiapruvoti, a BAP species, is growing at Gap Point (K.Cook, pers comm.) Wingletang Ledges and theCita wreck (Seasearch, 2006). <strong>The</strong> sunset cup coralpopulations in southwest England are at the northernlimit <strong>of</strong> their distribution and are thought to be a relic<strong>of</strong> a former, more extensive distribution approximately700 years ago (Jones et al n.d.). <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> isone <strong>of</strong> only four areas it is known to occur in the UK(Seasearch, 2007).Three species <strong>of</strong> BAP stalked jellyfish occur in <strong>Scilly</strong>;Haliclystus auricular, Lucernariopsis campanulata andLucernariopsis cruxmelitensis. <strong>The</strong>se small cnidariansare usually fixed to algae or seagrass by their stalk andmay have suffered from habitat loss when the seagrass<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 20

die-<strong>of</strong>f occurred. <strong>The</strong> timid burrowing anemoneEdwardsia timida, another BAP species, may have alsodeclined for this reason because it requires stablesediment in which to burrow. <strong>The</strong> only records <strong>of</strong> thisspecies are from the 1980s and it is not known whetherit still occurs in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.A number <strong>of</strong> nationally rare and scarce cnidarians arefound in <strong>Scilly</strong>, these include Weymouth carpet coralHoplangia durotrix, a nationally rare species has beenrecorded at Gap Point in the 1980s by 2 recorders.Two hydroids, Laomedea angulata and Aglaopheniakirchenpaueri (NBN Gateway), yellow cluster anemoneParazoanthus axinellae, latticed corklet Cataphelliabrodricii, the s<strong>of</strong>t coral Alcyonium hibernicum, theglaucus pimplet Anthopleura thallia are all nationallyscarce and found in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (Barne et al,1996).Some southern species <strong>of</strong> cnidarian are found in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> such as the trumpet anemone Aiptasiamutabilis (English Nature, 2000) which is found atseveral sites there but is nationally scarce and littlerecorded elsewhere in the UK.Apolemia uvaria, a string jelly was recorded in largenumbers <strong>of</strong>f the southwest <strong>of</strong> England including <strong>Scilly</strong>in the autumn <strong>of</strong> 2007. This species is planktonic andits sudden appearance in these waters may be relatedto changes in sea surface temperatures associated withclimate change although no solid conclusions can yetbe drawn with so little data (K.Hiscock, pers. comm.,P.Gainey, pers. comm.).Trends and IssuesSunset cup coral Leptopsammia pruvoti is classified asvery highly sensitive to substratum loss, smothering,dessication, emergence, salinity, physical disturbanceand displacement as well as being highly sensitive tocertain other stressors. Its larvae are short-lived andtend to settle very near the parent therefore there canbe problems with larval supply once adult coloniesare removed from an area and there may be no furtherrecruitment.ResearchA checklist <strong>of</strong> the Cnidaria and Ctenophora <strong>of</strong> <strong>Scilly</strong>was published in the Journal <strong>of</strong> Natural History in1969 as part <strong>of</strong> the series <strong>of</strong> papers on the marine life <strong>of</strong><strong>Scilly</strong> (Robins, 1969).<strong>The</strong> Seasearch pink sea fan survey has been conductedby volunteer divers in <strong>Scilly</strong> and at other sitesnationally. It aims to identify important areas forpink sea fans and to discover more about their habitatrequirements and biology. Divers photograph andmeasure individual colonies, noting the presence <strong>of</strong>sea fan anemones, sea fan nudibranchs, the condition<strong>of</strong> the fan and any debris entangling the colony.Fisheries ImpactsCorals are generally slow-growing and fragile.Branching species such as sea fans are particularlyvulnerable to damage by bottom gear. Trawling cancompletely remove colonies in just one event. Pottingmay also have direct physical impacts on sea fansand lost fishing line or net is <strong>of</strong>ten found entanglingcolonies.Pink sea fans were once commonly collected by diversas souvenirs however once it became known that thisspecies is so slow growing and scarce these recreationdivers quickly instigated a self-imposed moratoriumon their collection. <strong>The</strong> pink sea-fan is protected underSchedule 5 <strong>of</strong> the <strong>Wildlife</strong> and Countryside Act 1981against killing, injuring, taking possession and sale.Climate ChangePlanktonic species like jellyfish are brought to the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> by prevailing currents and winds. Any changein current patterns brought about by climate changemay influence the occurrence <strong>of</strong> these species in <strong>Scilly</strong>.Habitat LossBurrowing anemones may have been more abundantin the past when sediment was stabilized by extensiveZostera beds, their habitat was affected by the largescaleseagrass die <strong>of</strong>f in the 1930s (Manuel, 1988). <strong>The</strong>effect <strong>of</strong> this would also have been noticed in seagrassassociated hydroids such as the nationally scarceLaomedea angulata (Barne et al, 1996)Sea fan seaslug Tritonia nilsodneri on pink sea fan Eunicellaverrucosa (pink colour morph). Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 21 Annelida - Marine WormsOverviewMarine worms are a diverse group yet most areroughly similar in appearance and are <strong>of</strong>ten hard toidentify without specialist knowledge or laboratoryanalysis. For this reason they are generally underrecordedwith little known about their conservationconcerns.S<strong>of</strong>t sediments support rich communities <strong>of</strong> worms;they are also found in rocky crevices, on hardsurfaces, in kelp holdfasts and free-swimming. True(segmented) worms are called Annelids but there arealso several groups <strong>of</strong> worm-like creatures which arefound in the marine environment, these are covered inSection on lesser-studied phyla.In the marine environment worms play a criticalrole in breaking down organic matter, aerating andstructuring sediment. <strong>The</strong>y are the main prey <strong>of</strong> manyspecies <strong>of</strong> fish and birds.Important Areas<strong>The</strong> sediment shores and sand flats in the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> are important for marine worms. Some areas aredominated by the lugworm Arenicola marina, whosepresence is revealed by casts in the sand producedduring feeding (Warwick, 2004). Other areas <strong>of</strong>sediment are dominated by sand mason worms Laniceconchigela, sedentary filter feeders which live in tubeswhich they creates out <strong>of</strong> sand grains and mucus. <strong>The</strong>importance <strong>of</strong> St Martin’s flats for worms and otherinfauna is recognised and the area is a designated SSSI.Great Pool, a brackish lagoon on Bryher supports aspecies <strong>of</strong> Arenicola (Bamber et al, 2001).Conservation Importance<strong>The</strong>re are no worms in <strong>Scilly</strong> which are BAP species.In general worms are a very under-recorded group.In a 1971 expedition to <strong>Scilly</strong>, Harris found 17 rare ornewly recorded polychaete worm species for Britain,one <strong>of</strong> which was new to science. <strong>The</strong>y also found 10species <strong>of</strong> Spirobis (spiral worm) <strong>of</strong> which 2 were newto science.In a survey <strong>of</strong> the faunal communities on theundersides <strong>of</strong> intertidal boulders in <strong>Scilly</strong> in 1990,Foster-Smith found that spirobid worms were themost important group in terms <strong>of</strong> abundance. Sabellavariabilis, a small fan worm very rarely recorded inBritain, is abundant in <strong>Scilly</strong> (English Nature 1994)Trends and IssuesResearchA number <strong>of</strong> papers on worms and their relatives havebeen published in the series on the marine flora andfauna <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in the Journal <strong>of</strong> NaturalHistory. Harris published an inventory <strong>of</strong> the marinePolychaetes <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in 1972.PollutionSome worms process large amounts <strong>of</strong> sediment asthey feed and are vulnerable to accumulation <strong>of</strong> heavymetals or organic compounds in their tissues. Wormscan also assist in the breakdown <strong>of</strong> pollution. Intertidalspecies are at risk during oil spill incidents.Peacock worm Sabella pavonina. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 22 Arachnida - Spiders andrelativesOverviewSpiders, harvestmen, pseudoscorpions and mitesare collectively known as arachnids. Spidersare ubiquitous in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, being foundthroughout the inhabited islands and on some <strong>of</strong> theother islands, sometimes associated with seabirds andtheir nests.Pseudoscorpions are seldom encountered as they aremainly crevice-dwellers, being found under loosebark, inside rotting trees, or amongst leaf litter. Mites,<strong>of</strong> which 169 species have been recorded from the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong>, can be found in a vast array <strong>of</strong> habitats, suchas litter and rotting seaweed, but are so inconspicuousmost go unnoticed.Important Areas<strong>The</strong>re are no areas known to be <strong>of</strong> particularimportance, though coastal habitats are clearly <strong>of</strong>importance.Conservation Importance<strong>The</strong>re is one species on the BAP priority list:Silky gallows-spider Dipoena inornata, one <strong>of</strong> whichwas recorded by Bristowe on the dunes <strong>of</strong> Tresco in1929.<strong>The</strong>re is one RDB species:Clubiona genevensis is an RDB spider <strong>of</strong> coastalgrassland and heathland habitats. <strong>The</strong> Provisional Atlas<strong>of</strong> British Spiders refers to <strong>Scilly</strong> as one <strong>of</strong> its very fewBritish sites. Bristowe recorded significant numbers<strong>of</strong> this species in the period 1928-1934, especially onSamson.Trends and IssuesResearchAn attempt should be made to relocate Dipoenainornata, which has not been recorded for nearly 70years.Nursery web spider, Pisaura mirabilis. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 23 Crustacea – Crabs, lobsters,shrimps and relativesOverview<strong>The</strong> crustaceans are a group <strong>of</strong> animals with jointedlegs and chitinous exoskeletons which are shedperiodically. <strong>The</strong> largest order is the Decapoda whichincludes shrimps, crabs and lobsters. <strong>The</strong>re are over2000 species <strong>of</strong> crustacean in the waters surroundingthe British <strong>Isles</strong>, many are planktonic. Mostcrustaceans are mobile but some, like the barnacles,adopt a sessile lifestyle in their adult form.Crabs and shrimps are very common in intertidalareas. Shrimps are targeted by an artisanal fishery atspring low tides during the summer months in <strong>Scilly</strong>.Some crab species, lobsters and crayfish are caught bypotting in the fishing season. <strong>The</strong>re is a high diversity<strong>of</strong> isopods in <strong>Scilly</strong>; they are common under algae andin fresh water seeps on the shore (Parslow, 2007).Important AreasCrustaceans are found in a wide range <strong>of</strong> habitatssuch as intertidal pools, under boulders and in s<strong>of</strong>tsediment. One species, the chameleon prawn Praunusflexuosus, is found in vast numbers in Bryher Pool, abrackish environment, but most are marine (Parslow,2007).Conservation ImportanceCthalamus barnacles dominate the rocky shores in<strong>Scilly</strong>, unlike on mainland Southwest coasts whereSemibalanus balanoides is <strong>of</strong>ten dominant. This isthought to be due to larval supply problems for S.balanoides, which is rare in <strong>Scilly</strong> (English NatureNatural Area Pr<strong>of</strong>ile).A rare hermit crab Cestopagarus timidus has beenrecorded in intertidal areas in <strong>Scilly</strong> (Harvey, 1964),this is a species which typically has a more southerlydistribution. <strong>The</strong>re are also two recent records <strong>of</strong> rareslipper lobsters Scyllarus arctus another species at thenorthern limit <strong>of</strong> its range around <strong>Scilly</strong> (Herdson,2001). One individual was caught in a lobster pot andis now in the National Marine Aquarium in Plymouth.Typton spongicola, the sponge shrimp is a nationallyrare southern species which occurs in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>on sponges. Cranch’s spider crab Achaeus cranchii isfound on subtidal hydroids, bryozoans and seasquirts(Barne et al, 1996).Several nationally rare or scarce amphipods have beenrecorded in <strong>Scilly</strong>. Microdeutopus stationis, Ampherusaclevei and Pereionotus testudo are nationally rare (NBN)and Apherusa ovalipes is nationally scarce (Barne et al,1996). Synisoma lancifer a nationally scarce sea slater isalso found in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Trends and IssuesResearchInventories <strong>of</strong> some crustacean groups have beenpublished in the Journal <strong>of</strong> Natural History. <strong>The</strong>se arethe Eucarida (Thurston, 1969), Harpacticoid copepods(Wells, 1970), Ostracods (Neale, 1970) and Mysidshrimps (Makings, 1987).Release <strong>of</strong> captive bred lobsters<strong>The</strong> National Lobster Hatchery at Padstow has workedwith members <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Sea FisheriesCommittee and local divers to release 500 juvenilelobsters in 2002 and 120 in 2007 in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.<strong>The</strong>se were released by hand in suitable habitats andwill take many years to grow large enough to enter thefishery.FishingPotting for lobsters, crayfish and crabs has occurred in<strong>Scilly</strong> for many years. <strong>The</strong> impact on local populationsis largely unquantified. See section 3.3 on Fisheries.Spiny spider crab Maja squinado on dead man’s fingers Alcyonium digitatum. Photo: Frank Gloystein<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 24 Myriapoda - Centipedes andMillipedesOverviewCentipedes and millipedes belong to the classMyriapoda characterised by the number <strong>of</strong> legs theypossess. Centipedes are carnivores and millipedes eatvegetation, both are important members <strong>of</strong> the groundflora community, assisting in the breakdown <strong>of</strong> leaflitter and processing <strong>of</strong> organic matter.<strong>The</strong>y live in a variety <strong>of</strong> terrestrial habitats in the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong>.Conservation Importance<strong>The</strong>re is one species on the BAP priority list:Turk’s Earth-centipede Nothogeophilus turkiThis species was collected by Dr F.A. Turk andidentified as a new species as recently as 1988.Trends and IssuesResearch<strong>The</strong> distribution and population <strong>of</strong> Nothogeophilus turkishould be established.Important Areas<strong>The</strong> type locality for Nothogeophilus turki is Old TownBay, St Mary’s.White-legged snake millipede Tachypodoiulus niger on an apple. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 25 Odonata - Dragonflies andDamselfliesOverviewDragonflies and damselflies are members <strong>of</strong> the insectorder, Odonata, <strong>of</strong> which there are 41 species whichbreed regularly in the British <strong>Isles</strong>. <strong>The</strong>y are winged,carnivorous insects with brilliant metallic colouring,whose eggs are laid in water and develop throughaquatic larval stages for one to three years, beforeemerging and breeding in the terrestrial environment.In <strong>Scilly</strong> there are only two common resident species,blue-tailed damselfly Ischnura elegans and commondarter Sympetrum striolatum. Inevitably, there are anumber <strong>of</strong> migrants that have been recorded fromthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, including some like common bluedamselfly Enallagma cyathigerum that may breed onoccasion. Migrant hawker Aeshna mixta has recentlybeen confirmed as a breeding species over severalyears.Important Areas<strong>The</strong> Odonata need pools to breed and those poolswhere breeding populations occur are <strong>of</strong> somesignificance. <strong>The</strong> larger freshwater bodies on StMary’s and Tresco and St Agnes Big Pool are knownto have breeding populations <strong>of</strong> Odonata. Sometimessalt water intrusion may render one or other <strong>of</strong> thefreshwater pools unsuitable; for example, the St AgnesPool can temporarily be too brackish for dragonflies.Conservation Importance<strong>The</strong>re are no species <strong>of</strong> particular nationalconservation importance recorded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Trends and IssuesPollutionEutrophication <strong>of</strong> freshwater pools may affect thebreeding success <strong>of</strong> some species.Common darter Sympetrum striolatum. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 26 Orthoptera - Crickets,Grasshoppers and their relativesOverview<strong>The</strong> crickets and grasshoppers belong to the insectgroup, Orthoptera, together with earwigs andcockroaches. <strong>The</strong>y are generally a well studied,popular group, with about 30 British species.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are not particularly noted for theircricket and grasshopper diversity. <strong>The</strong>re are only ninenative species resident in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, but two <strong>of</strong>them are nationally scarce.<strong>The</strong>re are also occasional migrant or vagrant speciesrecorded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> such as species <strong>of</strong> locust.In addition, although they are non-native, the stickinsects<strong>of</strong> <strong>Scilly</strong> make an interesting – and well-known– contribution to the islands’ biodiversity. Pricklystick-insect Acanthoxyla geisovii and smooth stickinsectClitarchus hookeri originate in New Zealand andhave been known in the Abbey Gardens on Tresco formany years; more recently they have spread to ‘wild’habitats. <strong>The</strong>y have national RDB status.Important AreasNo particular areas have been identified for this group.Conservation Importance<strong>The</strong>re are no species on the BAP priority list that arefound in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, but there are two speciesthat are nationally scarce:• Lesser cockroach Ectobius panzeri is a Notable Bspecies found in coastal habitats around theislands.• Lesne’s earwing Forficula lesnei is a Notable Bspecies. <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is regularly cited as one<strong>of</strong> its strongholds.It is generally considered that introduced species, suchas the stick-insects, should not be considered as being<strong>of</strong> conservation importance.Trends and IssuesResearch<strong>The</strong> Orthopteran fauna is continually changing.Monitoring the status <strong>of</strong> each species, in particularthose that are nationally scarce, would be useful.Stick insects are non-native but have spread to wild habitats in <strong>Scilly</strong>. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 27 Hemiptera - BugsOverviewBugs are a large group <strong>of</strong> insects which belong to theorder Hemiptera; there are about 1700 types <strong>of</strong> bugsin Britain. <strong>The</strong> bugs are a diverse group <strong>of</strong> insects,including such well-known animals as shield bugs,water boatmen, greenfly, and whitefly. <strong>The</strong>y areprobably the most diverse insect group in Britain,although only the fifth largest in terms <strong>of</strong> species. <strong>The</strong>ynaturally fall into three major types:• Heteroptera – shieldbugs, lacebugs, damselbugs, ground bugs, flowerbugs, etc.• Auchenorrhyncha – froghoppers, leafhoppers,etc.• Sternorrhyncha – greenfly, whitefly, jumpingplant lice, etc.Important Areas<strong>The</strong>re are no areas known to be <strong>of</strong> particularimportance, though coastal habitats are clearly <strong>of</strong>importance.Conservation Importance<strong>The</strong>re are no species on the BAP priority list:<strong>The</strong>re are, however, several species <strong>of</strong> significance,including two Red Data Book species:• Emblethis verbasci is an RDB ground-bug(Lygaeidae) which is widely distributed insandy coastal habitats in <strong>Scilly</strong>, but whichotherwise has only two British sites. <strong>The</strong> Review<strong>of</strong> Scarce & Threatened Hemiptera leaves nodoubt that <strong>Scilly</strong> is its main stronghold.• Piesma quadratum spergulariae (a beet-bug,Piesmatidae) is classed as a ‘Rare (RDB)Endemic’ in the Review <strong>of</strong> Scarce & ThreatenedHemiptera. It was described as new to sciencefrom <strong>Scilly</strong> in the 1960s, and has not been foundelsewhere. It seems well established on theislands.• Strongylocoris luridus is a Notable capsidbug (Miridae). <strong>The</strong> Review <strong>of</strong> Scarce &Threatened Hemiptera refers to <strong>Scilly</strong> as one <strong>of</strong>its strongholds.• Dicranocephalus agilis is a Notable spurge-bug(Stenocephalidae) for which <strong>Scilly</strong> has been anoted site for many years.Trends and IssuesResearch<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are important for several bugs. Areview <strong>of</strong> the bugs, including their distribution andecology needs to be written.Green shield bug. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 28 Lepidoptera - Butterflies andMothsOverviewButterflies and moths are members <strong>of</strong> the insect order,Lepidoptera. <strong>The</strong>re are about 56 resident butterfliesand over 2000 moth species in the British <strong>Isles</strong>. <strong>The</strong>irbodies and wings are covered with small scales, <strong>of</strong>tenbrightly and variously coloured, forming characteristicpatterns.Butterflies are probably amongst the most popularinsects and most readily identified. <strong>The</strong> mothsare more difficult and include many smaller,inconspicuous specimens, collectively known asmicro-moths.Moths and butterflies are a well studied group in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. At least 539 species have been recordedfrom the islands; these include several nationalrarities. However, some <strong>of</strong> them may only occur dueto migration or vagrancy.Important AreasWhile large numbers <strong>of</strong> moths <strong>of</strong> conservationimportance have been recorded on the islands, thereappears to have been no assessment made <strong>of</strong> thoseareas that are <strong>of</strong> most importance.Conservation Importance<strong>The</strong>re are 34 species on the BAP priority list, but atleast nine have not been recorded for several decades,or may only occur as vagrants. <strong>The</strong>re are 25 specieson the list that deserve consideration. Of these, somelike the white and buff ermines are still common, but- nationally at least - in decline, others would appearalways to have been scarce.Grey DaggerAcronicta psiKnot GrassAcronicta rumicisBrown-spot PinionAgrochola lituraBeaded ChestnutAgrochola lychnidisEar MothAmphipoea oculeaMouse MothAmphipyra tragopoginisDusky BrocadeApamea remissaGarden TigerArctia cajaMottled RusticCaradrina morpheus<strong>The</strong> CrescentCelaena leucostigmaSmall Square-spotDiarsia rubiSmall PhoenixEcliptopera silaceata<strong>The</strong> RusticHoplodrina blandaRosy RusticHydraecia micaceaDot MothMelanchra persicariaeBroom MothMelanchra pisiRosy MinorMesoligia literosaPowdered QuakerOrthosia gracilisMullein WaveScopula marginepunctataWhite ErmineSpilosoma lubricipedaBuff ErmineSpilosoma luteumBlood-veinTimandra comae<strong>The</strong> CinnabarTyria jacobaeae<strong>The</strong> SallowXanthia icteritiaDark-barred Twin-spot Carpet Xanthorhoe ferrugata<strong>The</strong>re are additional species that are locally important.Of the butterflies, the speckled wood Pararge aegeriainsula that is recorded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is adistinctive endemic subspecies. <strong>The</strong> speckled woodis nationally common, but this form is unique to theislands (and very different from the mainland Britishform) and, although it is doing well in <strong>Scilly</strong> at present,historically its population seems to have fluctuateddramatically. Two other butterfly species also showslight differences, the subspecies <strong>of</strong> meadow brownManiola jurtina cassiteridium and the island variations<strong>of</strong> common blue Polyommatus icarus which werestudied by Ford (1975).<strong>The</strong>re are three moths which are RDB or nationallyscarce:• Thrift clearwing Bembecia muscaeformis is aNotable B species widespread around the coasts<strong>of</strong> <strong>Scilly</strong>• Nothris congressariella is an RDB species feedingon balm-leaved figwort Scrophularia scorodoniawhich was discovered as new to Britain onTresco, and has subsequently been recorded onthe other inhabited islands. It is otherwise foundonly at a few sites in <strong>Cornwall</strong> and Devon.• Yellow V moth Oinophila v-flava is an RDBspecies that in Britain is found in the open only in<strong>Scilly</strong>.Feathered ranunculus Eumichtis lichenea scillonea andshuttle-shaped dart Agrotis puta insula are both mothswith endemic subspecies in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Trends and IssuesResearchMore research is required in order to fully assess thestatus and diversity <strong>of</strong> the scarce and rare Lepidopterain the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. It is important that the status <strong>of</strong>the common and the rare biodiversity listed speciesSpeckled wood Pararge aegeria insula on bramble.Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 29 Diptera - Two-winged FliesOverviewFlies include the robber, crane, bee, soldier and hoverflies. <strong>The</strong>re are about 6000 species <strong>of</strong> fly in the British<strong>Isles</strong>, the majority <strong>of</strong> which are small and poorlyknownand <strong>of</strong>ten difficult to identify.Apart from those easily studied species such as thehoverflies, flies have not been particularly well studiedin the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in the past.Important Areas<strong>The</strong>re are no areas known to be <strong>of</strong> particularimportance for two-winged flies.Conservation Importance<strong>The</strong>re are no species on the BAP priority list:Aphrosylus mitis is a Notable dolichopodid or longheadedfly (Dolichopodidae). <strong>The</strong> Review <strong>of</strong> the Scarce& Threatened Flies <strong>of</strong> GB cites <strong>Scilly</strong> as one <strong>of</strong> its fewrecent sites.Trends and IssuesResearch<strong>The</strong> Dipteran fauna <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> needs furtherinvestigation.Narcissus fly Merodon equestris is a persistant pest in commercial narcissus crops. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 30 Hymenoptera - Wasps andBeesOverviewWasps, bees and bumble bees include the familiaryellow and black striped insects. However, the groupalso includes many lesser known species, some <strong>of</strong>which are parasitic. Many wasps and bees are solitaryorganisms, burrowing their nests into soils or wood,although some species are social, forming into largeorganised nests.Wasps and bees in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> tend to beparticularly noticeable, inhabiting gardens, heathland,moorland, hedgerows, coastal grassland, cliffs,sand dunes and former mining areas. <strong>The</strong>re are fewnationally important species found in <strong>Scilly</strong>, but thediversity <strong>of</strong> wasps and bees is rich.Important AreasSome <strong>of</strong> the coastal areas <strong>of</strong> St Agnes are <strong>of</strong> mostimportance for Bombus muscorum scyllonius, whileparts <strong>of</strong> St Mary’s appear to be central to the survival<strong>of</strong> Bombus jonellus in <strong>Scilly</strong>.Conservation Importance<strong>The</strong>re is one species on the BAP priority list:Moss carder-bee Bombus muscorum scyllonius<strong>The</strong> ‘<strong>Scilly</strong> bee’ is an endemic subspecies <strong>of</strong> the mosscarder bee, which had greatly declined (due to loss <strong>of</strong>coastal heathland and grassland) since the 1960s, buthas begun to show some signs <strong>of</strong> recovery in recentyears. Considering the general public familiaritywith bumblebees this could be an important ‘flagshipspecies’ for invertebrate conservation – and the widerissue <strong>of</strong> restoring coastal heathland/grassland habitatsin the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.<strong>The</strong>re is one other species <strong>of</strong> local interest, heathbumblebee Bombus jonellus. This is a nationally localspecies that has declined greatly in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>since the 1960s, but has shown some signs <strong>of</strong> recoverymore recently. It is in the <strong>Cornwall</strong> Red Data Book andis a good indicator <strong>of</strong> the health <strong>of</strong> coastal heathlandand grassland habitats.Trends and IssuesResearch<strong>The</strong> moss carder-bee Bombus muscorum scylloniusshould be monitored. <strong>The</strong> heath bumblebee, whichuntil 2004 was in serious difficulties in the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong>, should be studied so that the reason forpopulation fluctuations may be understood.<strong>The</strong> <strong>Scilly</strong> bee Bombus muscorum scyllonius is an endemic subspecies <strong>of</strong> the moss carder-bee. Photo: Andrew Cooper<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 31 Hymenoptera - AntsOverviewAnts are insects which are characterised by their socialbehaviour, forming well organised colonies. <strong>The</strong>ymostly have biting parts, which in some species releasea defensive chemical.Ants can be found in a variety <strong>of</strong> habitats includingheathland and various grasslands. In the British <strong>Isles</strong>there are nearly 50 ant species regarded as native, <strong>of</strong>which 14 have been recorded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. Onespecies, the red-barbed ant Formica rufibarbis, is foundat only one other site in Britain.Important AreasChapel Down on St Martin’s, Tean and some <strong>of</strong> theEastern <strong>Isles</strong> are important for the colonies <strong>of</strong> Formicarufibarbis.Conservation Importance<strong>The</strong>re is one species on the BAP priority list, thered-barbed ant, sometimes referred to locally as theSt Martin’s ant. Formica rufibarbis is, from a nationalpoint <strong>of</strong> view, the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s most importantinvertebrate rarity. <strong>The</strong>re is a current Heritage LotteryFund project for its conservation here and in Surrey, itsonly other British location. This is could be considereda ‘flagship species’ for public advocacy.Trends and IssuesResearchMonitoring <strong>of</strong> the species and further work on theecology <strong>of</strong> the species is necessary. <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>population remains stable while the only otherpopulation in Britain appears to be in terminal decline.<strong>The</strong> reb-barbed ant Formica rufibarbis is found on St Martin’s and one other site in Britain. Photo: IoSWT<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 32 Coleoptera - BeetlesOverviewBeetles are a large group <strong>of</strong> insects which belong tothe order Coleoptera. <strong>The</strong> beetles are one <strong>of</strong> the largestinsect orders, numbering some 3900 species in theBritish <strong>Isles</strong>. <strong>The</strong> beetles include such well-knowngroups such as ladybirds and weevils. <strong>The</strong>y arecharacterised by their hard, wing cases, which may becoloured or have a metallic appearance.<strong>The</strong> beetles <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have been relativelywell-recorded, with a species list <strong>of</strong> 568 species, butsome <strong>of</strong> the records are rather old.Important Areas<strong>The</strong> coastal areas are <strong>of</strong> importance for several rarebeetles, but the best areas within those coastal areas donot appear to have been described and published.Conservation Importance<strong>The</strong>re is one species on the BAP priority list:Meloe proscarabaeus black oil-beetle<strong>The</strong>re are 10 RDB species. Of the 10 species listed, themajority are <strong>of</strong> indeterminate status and the followingfour may be <strong>of</strong> most significance:Silpha obscura RDBPsylliodes hyoscanii RDBCathormiocerus maritimus RDBCathormiocerus myrmecophilus RDB<strong>The</strong> two Cathormiocerus species <strong>of</strong> weevil may beconsidered locally important for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Both are specialists <strong>of</strong> grazed sea-cliffs in the southwestand are threatened by cessation <strong>of</strong> coastal grazingand increased public pressure on cliff-top habitats.<strong>The</strong>re is one further species <strong>of</strong> significance: Tansy leafbeetleChrysolina graminis. This is a declining specieswith the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> as one <strong>of</strong> the few places withpost-1980 records. <strong>The</strong> recent Atlas <strong>of</strong> the Seed & LeafBeetles <strong>of</strong> Britain and Ireland says it should be upgradedfrom Notable A to RDB status, and that ‘it shouldqualify for BAP priority status’.Trends and IssuesResearchA report should be written describing the importantareas for the beetles <strong>of</strong> conservation concern.Habitat Loss<strong>The</strong> reduction in heathland grazing has had an adverseeffect on certain coastal grasslands, which in somecases could adversely affect certain beetle species.TourismIncreased visitor numbers have led to more trampling<strong>of</strong> certain areas and an increase in uncontrolled fires.Black oil beetle Meloe proscarabaeus. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 33 Mollusca – Slugs, snails,bivalves and relatives (marine)OverviewMolluscs are the largest and most diverse group <strong>of</strong>marine animals; they also inhabit freshwater andterrestrial habitats. Most are s<strong>of</strong>t bodied with acalcareous protective shell and no true skeleton. Insome groups such as octopuses and nudibranch seaslugs the shell has disappeared, or it may be internalsuch as in cuttlefish.Turk and Seaward (1997) produced an inventory <strong>of</strong>all mollusc species in <strong>Scilly</strong> and concluded that themolluscan fauna <strong>of</strong> the area was extremely rich. <strong>The</strong>ylisted over 400 species, representing over half themollusc species recorded for all <strong>of</strong> North West Europe.7.7% <strong>of</strong> the molluscs in <strong>Scilly</strong> are considered southernor Lusitanian species, and over three quarters <strong>of</strong> thespecies present are also found in the Mediterranean.Some molluscs which are common on the mainlandare much rarer in <strong>Scilly</strong>, for example the ediblemussel Mytilus edulis is almost absent from Scillonianforeshores. This is thought to relate to restricted larvalsupply.Molluscs are historically important as a protein sourcefor human inhabitants <strong>of</strong> <strong>Scilly</strong> and middens <strong>of</strong> limpetshells have been found there, some dating back to theBronze Age (Parslow, 2007).Important AreasMolluscs have exploited all <strong>of</strong> the diverse range <strong>of</strong>marine habitats in <strong>Scilly</strong>, from the tiny lagoon snailsPaludinella littorina (See Section in the sprayzone at the top <strong>of</strong> the shore to the burrowing razorshells in the sand and limpets on the rocky reefs. <strong>The</strong>sandflats support several biotopes including onewhich is dominated by razor shells Ensis spp. whichare burrowing bivalves (Warwick, 2004). <strong>The</strong> intertidalsandflats at St Martin’s are protected as a SSSI.Acanthocardia aculeata (nationally rare, spiny cockle),Bittium simplex (a nationally rare sea snail), Callistachione (a nationally rare bivalve), Gastrochaena dubia(a flask shell), Jujubinus striatus (a nationally rare,seagrass associated species once abundant in <strong>Scilly</strong>),Leptochiton scabridus (a nationally scarce chiton).<strong>The</strong> warty cockle Plagiocardium papillosum is thought tohave disappeared from <strong>Scilly</strong> (Barne et al, 1996).Lucinella divaricata is a bivalve which burrows in cleansand. In the UK has been found alive only in <strong>Scilly</strong> andit is a southern species.Trends and IssuesSpecies associated with seagrass, such as the fanmussel Atrina fragilis have declined in <strong>Scilly</strong> throughhabitat loss.Scallops Pecten maximus are found on sandy and gravelsea beds and are exploited by scallop dredging vessels<strong>of</strong>f the coast <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Shell collecting (especially for cowries Trivia arcticaand T. monacha) is popular with tourists in <strong>Scilly</strong>,though most shells will be empty when taken. If thishas any impact it may be on hermit crabs which woulduse some types <strong>of</strong> shell, rather than the molluscs thatoriginally inhabited the shells.A feasibility trial for abalone (ormer) aquaculturewas carried out a few years ago on St Martin’s andconditions were found to be suitable. However due tolocal opposition to the venture it never progressed toan operational phase in <strong>Scilly</strong> and was subsequentlyrelocated to the mainland (S.Watt, pers. comm.).Conservation Importance<strong>The</strong> fan mussel Atrina fragilis is a BAP species whichhas declined in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (S. Turk, pers comm.).This large bivalve used to be abundant in the intertidalzone in <strong>Scilly</strong> but is now rare there.Ostrea edulis, the native oyster is another BAP speciespresent, though rare in <strong>Scilly</strong>, this is decliningnationally. An attempt was made to introduce thisspecies for cultivation in <strong>Scilly</strong> but this largely failed(Turk and Seaward, 1997).A number <strong>of</strong> other molluscs have been recordedin <strong>Scilly</strong> which are identified as nationally rare orscarce. <strong>The</strong>se include the seaslugs Atagema gibba andDoris sticta (both nationally rare), Trapania pallidaand Tritonia nilsodneri (both nationally scarce);Painted topshell Calliostoma zizyphinum. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 34 Mollusca – Slugs, snails,bivalves and relatives (terrestrial andfreshwater)Overview<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is impoverished in terms <strong>of</strong>molluscan species compared to the mainland withsome species which are common on the mainlandbeing completely absent on <strong>Scilly</strong>, however for thearchipelago’s size the diversity <strong>of</strong> molluscs is relativelyhigh. Some molluscs show variations from mainlandforms due to their long separation from the mainlandfauna (Turk et al, 2001).<strong>The</strong>re are 70 species <strong>of</strong> terrestrial and freshwatermollusc recorded on <strong>Scilly</strong>, over half the UK species.<strong>The</strong> granitic rocks are an acidic substrate which is lessthan ideal for providing habitat for snails which needcalcium to create their shells.Important Areas<strong>The</strong> supralittoral zone or spray zone at the top <strong>of</strong> theshore is important for many gastropods which are<strong>of</strong>ten found in caves and strandline vegetation.<strong>The</strong> sand dunes <strong>of</strong> <strong>Scilly</strong> are generally graniticnot calcareous like those in <strong>Cornwall</strong> but thereare areas <strong>of</strong> shell sand that still support the samespecies assemblage as <strong>Cornwall</strong> apart from theround–mouthed snail Pomatias elegans which is absentin <strong>Scilly</strong>. Maritime grassland and heathland areimportant for snails in <strong>Scilly</strong>.<strong>The</strong> shortage <strong>of</strong> freshwater habitats in <strong>Scilly</strong> meansthat there are few wetland mollusc species. Severalpond snail species and five species <strong>of</strong> pea mussel arepresent (Turk et al, 2001).St Mary’s has the largest mollusc fauna and supportsnearly all the species recorded in <strong>Scilly</strong> whereas thesmaller islands have lower species richness (Cameron,2006).Conservation ImportancePaludinella littorina the lagoon snail is protected bythe Wildilife and Countryside Act, 1981. <strong>The</strong> <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> is considered the stronghold for this specieswhich lives in the supralittoral zone in rocky creviceson rugged granite boulder shores (Light and Kileen,2001). This species lives just on the boundaries <strong>of</strong> theSSSIs which are drawn at the high water mark.None <strong>of</strong> the other terrestrial or freshwater molluscson <strong>Scilly</strong> are BAP species or species <strong>of</strong> conservationconcern however they are important prey for birdssuch as the song thrush.Trends and IssuesResearchRichards and Robson (1926) recorded 42 species <strong>of</strong>mollusc on <strong>Scilly</strong> in 1925.Holyoak (2003) found ten mollusc species which werenew to <strong>Scilly</strong> including local and introduced species.Cameron (2006) recorded 51 species from islands.Introduced speciesA number <strong>of</strong> snail species have been introduced to theislands. <strong>The</strong>se include the garden snail Cornu aspersumwhich is abundant in dunes and coastal habitatsincluding being widespread on the uninhabited island<strong>of</strong> Annet (Holyoak 2003; Parslow, 2007). Introductionsmay have been by human inhabitants or smallerspecies could have arrived attached to birds (Cameron,2006).No exotic species <strong>of</strong> mollusc have been recordedin <strong>Scilly</strong> but Holyoak (2003) speculates that theintroduction <strong>of</strong> exotic plants to Tresco Abbey Gardensmay have led to the introduction <strong>of</strong> associated molluscspecies yet to be found. <strong>The</strong>re is conjecture that theslug Boettgerilla pallens was introduced in this way(Cameron, 2006).White lipped snail Cepaea hortensis. Photo: Colin Butler<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 35 Bryozoa – Sea MatsOverviewBryozoans are known as sea mats or moss animals andare colonial animals some <strong>of</strong> which resemble plants.<strong>The</strong>y are groups <strong>of</strong> tiny zooids which use tentaclesto filter feed on microscopic organisms. Bryozoansmay grow on other species such as kelp, or on rockysurfaces. Some species are s<strong>of</strong>t and gelatinous whileothers such as ross coral Pentapora foliacea are hard andcalcified. <strong>The</strong>y are <strong>of</strong>ten overlooked or confused withalgae and are consequently under recorded. <strong>The</strong>y arean important food source for many species <strong>of</strong> seaslug.<strong>The</strong>re are about 270 species <strong>of</strong> bryozoan in Britain,most are marine and about 80 are known in <strong>Scilly</strong>(Hayward, 1971).Important AreasAreas <strong>of</strong> hard rocky substrate or abundant algae arelikely to be important for bryozoans which normallygrow or encrust on hard surfaces or seaweeds.Turbicellepora magnicostata is very common on fucoidseaweeds on relatively sheltered beaches on StMartin’s and St Mary’s (R. Parslow, pers.comm.).Conservation Importance<strong>The</strong>re are no species <strong>of</strong> bryozoan which are designatedBAP species. Little is known about impacts orconservation issues relating to bryozoans but they arethought to be sensitive to pollution and particularlyvulnerable to sedimentation (Bratton, 1991).<strong>The</strong> Joint Nature Conservation Committee identified anumber <strong>of</strong> scarce and rare marine species for a review<strong>of</strong> <strong>Scilly</strong>. One <strong>of</strong> these was the orange-peel seamat orlace coral Turbicellepora magnicostata which occurs onvery exposed coasts there which are unusual in theirexposure compared to other locations in southernBritain (Barne et al, JNCC). This species was also notedby Seasearch divers from Aberystwyth University asit is normally found in the Mediterranean (Seasearch,2007). Both Turbicellepora magnicostata and Schizoporelladunkeri are southern species whose only UK recordsare from the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (Seasearch, 2007). This maybe partly due to a lack <strong>of</strong> recording effort at other UKsites.Watersipora complanata is a nationally rare intertidalspecies with a southern distribution found in <strong>Scilly</strong>(Barne et al, 1996).Trends and IssuesResearch<strong>The</strong> bryozoans <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have been studiedby Hayward (Hayward 1971 and 1976) and twospecies lists have been published in the Journal <strong>of</strong>Natural History.Ross coral Pentapora foliacea and anemones. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 36 Echinoderms – sea urchins,starfish, brittlestars and relativesOverviewEchinoderms are the Echinoidea (sea urchins),Asteroidea (starfish), Ophiuroidea (brittle stars),Crinodea (feather stars) and the Holothuroidea (seacucumbers). All are marine and are characterised byradial symmetry (normally five-rayed) and calcareousspiny plates or ossicles. <strong>The</strong>y move slowly, using awater vascular system with hundreds <strong>of</strong> tube feetalthough a few species such as crevice sea cucumbersPawsonia saxicola are sessile. Tube feet also haveimportant roles in respiration, burrowing and feeding.In Britain there are over 90 species <strong>of</strong> echinodermliving within the 200m depth contour (Southward andCampbell, 2006). <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have been notedfor their echinoderm fauna, with about 50 speciesrecorded there (Rowe, 1972), in particular the prolificburrowing heart urchins.Important Areas<strong>The</strong> intertidal sand flats at St Martin’s and throughoutthe archipelago support aggregations <strong>of</strong> Echinocardiumcordatum and Spatangus purpureus (both heart urchins),the latter is never usually found in the intertidalelsewhere in the UK, tending to live only in sublittoralareas (English Nature Natural Area report). In someareas such as Old Grimsby Harbour, Tresco, thedensity <strong>of</strong> Echinocardium cordatum is up to 25 persquare metre (Nichols and Harris, 1982).Kelp forests are important habitats for commonurchins Echinus esculentus which also live in deeperwater. In the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> they are common in mostsublittoral areas and the effects <strong>of</strong> their grazing aremost noticeable in the circalittoral on bedrock andboulders (Hiscock, 1984).Conservation ImportanceNone <strong>of</strong> the echinoderms present in <strong>Scilly</strong> are BAPspecies and no rare or scarce species have beenhighlighted as present in <strong>Scilly</strong>.Trends and IssuesResearchRowe (1971) published a paper on the echinoderms <strong>of</strong><strong>Scilly</strong> in the Journal <strong>of</strong> Natural History.CollectionEchinus esculentus has been exploited in British waterssince the 1960s for the curio trade (Bishop, 1985).In <strong>Scilly</strong> it was collected for some years and theimpacts <strong>of</strong> the fishery were studied in 1985 by Bishop.Collection is by hand, thus causing little damage tothe surrounding habitat but as an omnivorous grazer,this species is important in influencing growth <strong>of</strong>epiphytes in kelp forests (Bishop, 1985). Bishop foundthat the impacts <strong>of</strong> the fishery were negligible despitethe removal <strong>of</strong> 40,000 individuals in certain years, butwarned that monitoring should be continued. At thepresent time, only very low level exploitation occursand is unlikely to pose a significant threat to thepopulation.PollutionEchinoderms are sensitive to heavy metals and oil(MarLIN, <strong>2008</strong>). <strong>The</strong>y can be threatened by extraction<strong>of</strong> sand or gravel (Southward and Campbell, 2006).Cotton spinner Holothuria forskali and a starfish Henricia sp. on a rocky reef. Photo: Frank Gloystein<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 37 Tunicates – Larvaceans,thaliaceans and ascidiansOverviewTunicata (or Urochordata) is a subphylum <strong>of</strong> thephylum Chordata which means that these species havea dorsal nerve cord (a notochord), like the vertebrates.Most members <strong>of</strong> the Tunicata only show thischaracteristic in their larval stages and it disappears inadult stages. <strong>The</strong>re are 60 species <strong>of</strong> tunicate in Britainand approximately 50 have been recorded around<strong>Cornwall</strong> and the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (Gainey, 1997).Seasquirts are the most noticeable members <strong>of</strong> theTunicata and are <strong>of</strong>ten seen on rocky substrate orgrowing on algae. Seasquirts may be solitary orcolonial and are sessile benthic species which attach tohard surfaces and filter feed by passing water throughtheir siphons.Both the Larvacea and the Thaliacea are freeswimming planktonic members <strong>of</strong> the Tunicata. Rowe(1972) studied these groups in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> andfound one species <strong>of</strong> Larvacean Oikopleura dioica to bevery common in the plankton at night. <strong>The</strong> ThaliaceanDoliolum nationalis was also present in the nightplankton and was the only member <strong>of</strong> the Thaliaceapresent in <strong>Scilly</strong>.Important AreasAdult seasquirts colonise rocky areas therefore thesheltered intertidal boulders and subtidal rocky reefsare likely to be important for this group. Lightbulbseasquirts Clavelina lepadiformis and star ascidiansBotryllus schlosseri are attractive species which arepopular with divers and have been recorded onseveral reefs around the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong>y also growon seaweeds and their holdfasts.Conservation Importance<strong>The</strong> orange lights seasquirt Pycnoclavella aurilucenshas been recorded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and is anationally scarce species. This species has a southwesterndistribution in Britain and is a southernspecies thought to extend to the Mediterranean. Twoother nationally scarce sea squirts occurring here arePhallusia mammillata and Molgula oculata (Barne et al,1996).Trends and IssuesResearchRowe (1972) published a list <strong>of</strong> the Enteropneusta(acorn worms), Ascididiacea (seasquirts), Thaliacea(salps), Larvacea (larvaceans) and Cephalochordata <strong>of</strong>the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in the Journal <strong>of</strong> Natural History.Lightbulb seasquirts Clavelina lepadiformis. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 38 Lesser-studied phylaOverview<strong>The</strong>re are a number <strong>of</strong> marine phyla present in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> about which less is known due to thelack <strong>of</strong> recording effort or the difficulties <strong>of</strong> studyingthem.Single celled organismsSingle celled organisms form the basis <strong>of</strong> manyfood chains. In the marine environment, planktonicorganisms bloom in late spring as daylight increasesand the water begins to warm. <strong>The</strong> dominantphytoplankton species in the Celtic Sea are Skeletonemacostatum and Thalassiosira spp. (Edwards and John,1996). <strong>The</strong> phytoplankton bloom triggers a bloom <strong>of</strong>zooplankton grazers, then their predators bloom andlarger planktivores such as basking sharks appear.Marine protozoa, both interstitial flagellates andciliates and also Foraminifera are extremely numerousand diverse in <strong>Scilly</strong> (Harvey, 1969). <strong>The</strong> Foraminiferaare large for single celled organisms and cansometimes be seen with the naked eye. <strong>The</strong>y weresampled and recorded in <strong>Scilly</strong> by Atkinson in 1970 aspart <strong>of</strong> the series in the Journal <strong>of</strong> Natural History.<strong>The</strong> continuous plankton recorder (CPR) survey haspassed through the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> every year since 1950,taking an average <strong>of</strong> 40 samples per year.Many marine species and habitats have received little study because they are inaccessible, minute or otherwise difficult to research.Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 39

Ctenophora<strong>The</strong> Ctenophora or comb jellies, a group <strong>of</strong> gelatinousplanktonic animals, similar in appearance to jellyfishare present in the waters around the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Robins (1969) published a list <strong>of</strong> the Cnidaria andCtenophora in the Journal <strong>of</strong> Natural History.Platyhelminthes / Turbellaria (Flatworms)<strong>The</strong>se have flattened bodies and <strong>of</strong>ten live as parasites.In 1986 a paper on parasitic Digenea (a type <strong>of</strong>flatworm) in marine snails was published by Newell.Faubel and Warwick (2005) studied the freelivingflatworms (Turbellaria) <strong>of</strong> <strong>Scilly</strong> to produce aninventory. <strong>The</strong>y found 67 species <strong>of</strong> flatworms wherethere were previously only 3 species recorded. Ofthese, 6 were new to science.Nemertea (Ribbon worms)In 1993 Senz published a paper describing five newspecies <strong>of</strong> marine Nemerteans which had all beencollected from the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong>re are only 2known species <strong>of</strong> terrestrial ribbon worms in <strong>Scilly</strong>,both are introduced species. Argonemertes dendyi isfrom Western Australia and Antiponemertes pantini isfrom New Zealand.Rotifera<strong>The</strong>se ‘wheel animalcules’ are less than 2mm long andhave not been studied in <strong>Scilly</strong>.Gastrotricha (Hairybacks)Hummon and Warwick (1990) studied the hairy-backs(Gastrotricha) <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and listed 31 specieswhere there were previously none recorded, one being‘thus far endemic to <strong>Scilly</strong>’.Kinorhyncha (Thorn-skins)<strong>The</strong>re are 16 known British species <strong>of</strong> these interstitialmei<strong>of</strong>auna. <strong>The</strong>y have not been studied in the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong>.Nematoda (Eel worms)Warwick and Coles produced a checklist <strong>of</strong> free livingNematoda in <strong>Scilly</strong>, published in 1977 which detailed103 species, 16 <strong>of</strong> which were new to Britain and 6were new to science.Entoprocta<strong>The</strong>se are microscopic animals which may becolonial or solitary and may be associated with otherinvertebrates. Hayward (1971) published a list <strong>of</strong>Bryozoa and Entoprocta <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in theJournal <strong>of</strong> Natural History.Drift is characterised by Sagitta tasmanica.Sipuncula<strong>The</strong>se are unsegmented worms which have not beenstudied in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Echiura<strong>The</strong>se are unsegmented worms which have not beenstudied in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Chelicerata (Sea spiders and marine mites)In 1972, King published a list <strong>of</strong> Pycnogonids (seaspiders) a group <strong>of</strong> non-crustacean marine arthropods<strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Brachiopoda (Lamp shells)<strong>The</strong>se are ancient sessile marine animals with dorsaland ventral valves, they have not been studied in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Phoronida (Horeshoe worms)Phoronids or horseshoe worms are another wormlikephylum. Only two species have been recordedin <strong>Scilly</strong>, Phoronis muelleri and Phoronis pallida (NBNGateway, <strong>2008</strong>)Hemichordata (Acorn worms)Rowe (1972) recorded two species <strong>of</strong> acorn worms(Enteropneusta) in <strong>Scilly</strong> which, though worm likein appearance, belong to a separate phylum, theHemichordata.TardigradaKing and colleagues in 1981 published a paper listingthe marine tardigrades (sometimes called water bears)<strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong>se unusual small animals arecurrently classified in their own phylum (Tardigrada)which is thought to be related to the arthropods.CephalochordataOne species <strong>of</strong> cephalochordate, a phylum relatedto the tunicata has been recorded in <strong>Scilly</strong>, this isBranchiostoma lanceolatum. Rowe (1972) published alist <strong>of</strong> the Enteropneusta (acorn worms), Ascididiacea(seasquirts), Thaliacea (salps), Larvacea (larvaceans)and Cephalochordata <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in theJournal <strong>of</strong> Natural History.Chaetognatha (Arrow worms)<strong>The</strong>se small wormlike species can be used as indicatorspecies and are useful in characterising water masses.<strong>The</strong> water mass from the south/south west <strong>of</strong><strong>Scilly</strong> is characterised by certain species such as thechaetognath Sagitta serratodentata, the North Atlantic<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 40 Amphibia – frogs, toads andnewtsOverviewAmphibians include frogs, toads and newts. <strong>The</strong> <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> seems suitable for the three species that arefound in <strong>Cornwall</strong>, but only one is certainly foundthere.<strong>The</strong> common frog Rana temporaria is found on StMary’s and possibly on Tresco, but the commontoad Bufo bufo – if it ever existed in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>- appears to be extinct and there are no records <strong>of</strong> anyspecies <strong>of</strong> newt.the common frog.Conservation Importance<strong>The</strong>re are no species on the BAP priority list that arefound in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and the common frog doesnot appear to be currently threatened here and is not anational conservation priority.Trends and IssuesResearchMore research is required in order to fully assess thestatus <strong>of</strong> the common frog on St Mary’s and Tresco.Anecdotal evidence indicates that the population mayhave declined in the past, perhaps due to pesticide useand/or the lack <strong>of</strong> ditch maintenance.Important Areas<strong>The</strong> mires and ponds <strong>of</strong> St Mary’s are important forCommon Frog Rana temporaria. Photo: JB&S Bottomley<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 41 Freshwater and Marine FishOverviewFish belong to the phylum Chordata and are dividedinto the Chondrichthyes (cartilaginous fish) andOsteichthyes (bony fish), with members <strong>of</strong> both groupsfound in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. Fish are found throughoutthe marine environment in <strong>Scilly</strong> including specieswhich live in rockpools on the shore, demersal (bottomdwelling) species and pelagic (open water) fish. As anoceanic archipelago <strong>Scilly</strong> is important for both coastaland oceanic species. <strong>The</strong> young <strong>of</strong> some fish speciesmay be found in rockpools or in the shelter <strong>of</strong> seagrassbeds which they use as nursery areas. <strong>The</strong>re are moreBAP species <strong>of</strong> fish in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> than any othergroup <strong>of</strong> marine species.Pollack and wrasse are commonly sighted in shallowwaters around the coasts and wrasses are the groupmost commonly observed by divers (Seasearch,2005). Grey mullet shoal all around the islands andare frequently stranded in shore pools and largerlakes such as Great Pool on Bryher and Porth HellickPool on St Marys. Mackerel shoals are <strong>of</strong>ten seen inlate summer, followed by seabirds (R.Parslow, pers.comm.).Important AreasFish are distributed throughout the waters <strong>of</strong> the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> from surface waters e.g. sunfish, to deeperbenthic species such as plaice. Seagrass beds are animportant nursery area for juveniles <strong>of</strong> many fishspecies. <strong>The</strong>ir structural complexity provides shelterand refuge from predation for small fish. <strong>The</strong>y alsosupport populations <strong>of</strong> seahorses which are thoughtto breed there. In the intertidal areas, rockpoolsare important for small fish species and juveniles.Some small fish survive under dense algae amongstintertidal boulders and on sand flats.<strong>The</strong>re are freshwater fish in some <strong>of</strong> the pools on <strong>Scilly</strong>and species that migrate between freshwater andseawater.Galeorhinus galeus,Tope SharkHippocampus guttulatus (H. ramulosus),Long Snouted SeahorseHippocampus hippocampus, Short Snouted SeahorseHippoglossus hippoglossus*, Atlantic HalibutIsurus oxyrinchus,Shortfin MakoLamna nasus,PorbeagleLeucoraja circularis**, Sandy RayLophius piscatorius,Angler fishMerlangius merlangus, WhitingMerluccius merluccius, European HakeMicromesistus poutassou*, Blue WhitingMolva molva,LingPleuronectes platessa, PlaicePrionace glauca,Blue SharkRaja undulata,Undulate RayRostroraja alba*,White or BottlenoseSkateScomber scombrus,MackerelSolea soleaDover SoleSqualus acanthias,Spiny DogfishSquatina squatina,Angel SharkThunnus thunnus,Bluefin TunaTrachurus trachurus,Horse MackerelAnguilla anguilla,European EelSalmo salar,SalmonSalmo trutta,Sea Trout* <strong>The</strong>se are generally deeper water species and maynot occur within the 50m depth contour around the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.** Though recorded as present, these species areprobably very rare in the waters around <strong>Scilly</strong> and nottypical <strong>of</strong> the fish fauna <strong>of</strong> the area.Basking sharks Cetorhinus maximus, are the largestfish in British waters (up to 12m in length) and arecommonly sighted around <strong>Scilly</strong>, particularly insummer months. <strong>The</strong>y are plankton feeders and willmove great distances to reach frontal areas where theplankton is rich. <strong>The</strong>y are <strong>of</strong>ten seen in associationConservation Importance<strong>The</strong>re are 32 fish species recorded in <strong>Scilly</strong> which arenational BAP species, <strong>of</strong> these 12 are elasmobranchs(Sharks, skates and rays) and the rest are bony fish.Three species migrate between freshwater andseawater. <strong>The</strong>re is a grouped species action plan forCommercial Marine Fish which looks at management<strong>of</strong> individual stocks. In <strong>Scilly</strong> stocks <strong>of</strong> cod, plaice,herring, mackerel and sole are included.Ammodytes marinus,Cetorhinus maximus,Clupea harengus,Coryphaenoides rupestris*,Dalatias licha*,Dipturus batis**,Gadus morhua,Lesser Sand EelBasking SharkHerringGrenadierKitefin SharkCommon SkateCodCuckoo wrasse labrus mixtus. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 42

with herring Clupea harengus and mackerel Scomberscombrus which are also plankton feeders (NaturalArea Pr<strong>of</strong>ile). As well as being BAP species, baskingsharks also receive protection under the <strong>Wildlife</strong> andCountryside Act, 1981.Blue sharks Prionace glauca are a south-west UKspecies for part <strong>of</strong> the year and are probably the mostcommon sharks around our coast and also the mostheavily fished (K. Collins, pers.comm.). Angel sharksSquatina squatina have been declared extinct in theNorth Sea and have just (<strong>2008</strong>) been given protectionunder Schedule 5 <strong>of</strong> the <strong>Wildlife</strong> and Countryside Act1981.Mackerel is one <strong>of</strong> the most abundant pelagic species<strong>of</strong>f the west coast <strong>of</strong> Britain; it is common in the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> and is protected under a grouped species BAP.Mackerel spawn along the edge <strong>of</strong> the continental shelfand west <strong>of</strong> the southwest peninsula then migrate tocoastal waters after spawning (Pawson and Robson,1996). Mackerel are managed by quotas and minimumlanding size regulations. Herring, cod, whiting,European hake, plaice, Dover sole are also managedusing quotas and minimum landing sizes. Angler fishhave no minimum landing size but quotas are in place(Pawson and Robson, 1996.)Sandeels are common around <strong>Scilly</strong> and lesser sandeelAmmodytes marinus is a BAP species (Hiscock, pers.comm.). <strong>The</strong>y are an important food source for manyother fish and seabirds. <strong>The</strong>ir distribution is dependenton the presence <strong>of</strong> coarse sand in which they burrow(Natural Area pr<strong>of</strong>ile).Cod Gadus morhua is seasonally abundant in <strong>Scilly</strong>despite threats in other areas <strong>of</strong> its range (for examplethe North Sea). It has been suggested that cod migratebetween inshore waters in winter months and deepwater wrecks and reefs in the summer (EN NaturalArea Pr<strong>of</strong>ile).Plaice Pleuronectes platessa are the most abundantcommercial flatfish, usually found on sandy substrate.<strong>The</strong>y are long lived and take three years to reachmaturity. Dover sole Solea solea is found <strong>of</strong>f the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> and is caught in trawls. Dover sole spawnaround the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and juveniles spend up totwo years in inshore waters (Natural Area Pr<strong>of</strong>ile).Ling Molva molva spawn at the edge <strong>of</strong> the continentalshelf and use all the waters around <strong>Scilly</strong> and thesouth-west peninsula as a nursery area (Pawson andRobson, 1996). <strong>The</strong>y are commonly found aroundstony areas, reefs and wrecks and are sometimessighted by divers in <strong>Scilly</strong>.Short-snouted seahorses Hippocampus hippocampus arethought to breed in the eelgrass beds in <strong>Scilly</strong>. <strong>The</strong>yare on the IUCN Red List <strong>of</strong> threatened species asVulnerable, they are also an OSPAR priority species(Garrick-Maidment, 2007). Long-snouted seahorsesHippocampus guttulatus may also be present. In <strong>2008</strong>both species <strong>of</strong> seahorse received protection underSchedule 5 <strong>of</strong> the <strong>Wildlife</strong> and Countryside Act 1981.This makes it illegal to kill or take them and possession<strong>of</strong> a seahorse will also become an <strong>of</strong>fence. Protectionextends to the seahorses’ habitat as it will be illegalto damage or obstruct their place <strong>of</strong> shelter or evendisturb them in their place <strong>of</strong> shelter.Salmon, sea trout and European eel are exploiteddiadromous fish which means they spend part <strong>of</strong> theirlifecycle in freshwater and part in the sea. Salmon andsea trout reproduce in freshwater and then migrateout to sea; for European eels it is the other way round,they spawn at sea then migrate up rivers (Aprahamianand Robson, 1996).Seasearch surveyors found a boar fish Capros aperwhich is common in water <strong>of</strong> about 100m butvery rarely found in shallow water. Goodwin andPicton (2007) found the rare red blenny Parablenniusruber which is also known in Scotland and Ireland.Seasearch surveyors also noted the presence <strong>of</strong> thisspecies in 2007. Montague’s blenny Coryphoblenniusgalerita is a common species in higher rockpools in<strong>Scilly</strong> (Parslow, 2007); this is a species with a southerndistribution which reaches its northern limits insouthwest Britain.<strong>The</strong> grey triggerfish Balistes capriscus is found in<strong>Scilly</strong> and is generally a warmer water species whichhas become better established on the south coast <strong>of</strong>Britain in the last 40 years. White sea bream Diplodussargus and almaco jacks Seriola rivoliana are recentwarm water immigrants to the area (D.Herdson, pers.comm.).Pilchards Sardinia pilchardus are a commercially fishedspecies which has an important spawning area to thesouth <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and Land’s End (Pawsonand Robson, 1996).Long spined sea scorpions Taurulus bubalis are found in rockpoolsand deeper water. Photo: Malcolm NimmoEuropean eels Anguilla Anguilla are found in most<strong>of</strong> the larger freshwater pools on the islands. Greymullet also get stranded in the pools and gobies<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 43

Pomatoschistus minutus and P.microps are found insome (Bamber et al, 2001).<strong>The</strong> giant goby Gobius cobitis is nationally scarce and isa Mediterranean species, at the northern extreme <strong>of</strong> itsrange. It occurs only in the far south west <strong>of</strong> England,including a significant population in <strong>Scilly</strong> (Potts andSwaby, 1995). Giant gobies are listed on Schedule V <strong>of</strong>the <strong>Wildlife</strong> and Countryside Act 1981, which protectsthem from intentional killing, injuring or taking.Trends and IssuesResearchDr Peter Henderson <strong>of</strong> the University <strong>of</strong> Oxford iscurrently compiling a fish species inventory for theJournal <strong>of</strong> Natural History as part <strong>of</strong> the All Taxon<strong>Biodiversity</strong> Inventory.Ren Hathway has been working with DouglasHerdson (National Marine Aquarium) and Dr PaulGainey to update the fish species checklist publishedby the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> museum in 1971.Dr Ken Collins from Southampton University hasbeen carrying out research on the shark populations<strong>of</strong> <strong>Scilly</strong> for the last six years with particular focus onthe Blue Shark. Most <strong>of</strong> the blue sharks which havebeen tagged have been females and there has been arecapture or tag retrieval rate <strong>of</strong> approximately tenpercent (J Pender, pers. comm., Whittaker, 2001.).This wide ranging species has been shown to movefrom the east coast <strong>of</strong> the United States, to Portugaland north to <strong>Scilly</strong>. <strong>The</strong>y appear in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>between June and September and are thought to befeeding on mackerel.Porbeagles have also been tagged under the sameshark tagging study but in far fewer numbers. <strong>The</strong>re isspeculation that these species are now being activelytargeted by fishing boats from the UK mainland.Basking sharks records are being collected bythe Marine Conservation Society as part <strong>of</strong> theirSharkwatch programme. <strong>The</strong>y can migrate overlarge distances to feed at fronts where planktonaccumulates. During winter they have been shown tomove further <strong>of</strong>fshore to the edge <strong>of</strong> the continentalshelf where they perform daily dives to great depths t<strong>of</strong>eed (D. Simms, pers. comm.).Climate ChangeCertain fish species may act as climate changeindicators. Atlantic triggerfish have begun to appearfrequently in waters around <strong>Scilly</strong> and the southwest coast where they were previously very rarelysighted. It is suspected that they are now breeding inour waters and this represents a range extension tothe North. As the far southwest outpost <strong>of</strong> the UK,these range extensions are likely to be noticeable in<strong>Scilly</strong> before other parts <strong>of</strong> the southwest peninsulaand there are some species that are expected to spreadnorth soon and should possibly be highlighted t<strong>of</strong>ishermen to encourage recording when these speciesappear.FishingSee section 3.3, fishing.<strong>The</strong>re are two trawlers operating from St Marys whichtarget demersal species. <strong>The</strong>se may affect other bottomdwelling species such as skates and rays, flatfish etc.Small scale netting and potting is conducted aroundthe islands by seasonally operating fishing boats.<strong>The</strong>se operations target mullet and occasionallysalmon. Recreational anglers target species which arecaught by hook and line from the shore or from boatsfishing on nearby reefs. Some species, like cod arethreatened by largescale fisheries elsewhere in theirrange.Sharks and fish with large ranges are most at riskoutside the waters <strong>of</strong> <strong>Scilly</strong>. Blue sharks, for example,are a wide-ranging pelagic species which is heavilyoverfished. <strong>The</strong>y require European and globalconservation measures to halt their decline (K. Collins,pers. comm.). Elasmobranchs have a life history whichmakes them vulnerable to exploitation with long livesand slow reproductive rates.Habitat LossLoss <strong>of</strong> seagrass is likely to affect the juveniles <strong>of</strong> manyspecies. Others like seahorses rely on seagrass beds astheir breeding grounds.Angler fish Lophius piscatorius lie camouflaged on the seabed ready to ambush their prey. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 44 Terrestrial ReptiliaOverview<strong>The</strong> terrestrial reptiles encompass lizards, slow wormsand snakes. <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> support reptiles both onland and at sea. <strong>The</strong> only terrestrial reptile is the slowworm Anguis fragilis which is found on Bryher. It isknown to be an introduction.Important AreasThose parts <strong>of</strong> Bryher, such as land adjacent to GreatPopplestone Bay, are <strong>of</strong> importance.Conservation Importance<strong>The</strong>re is only one species on the BAP priority list,the slow worm, which is known to have been anintroduction in or before 1960s.Trends and IssuesResearchMore research is required in order to fully assess thestatus <strong>of</strong> slow worms on Bryher.ManagementAny hedge management on Bryher should take intoaccount the presence <strong>of</strong> slow worms.Public Awareness<strong>The</strong> law relating to slow worms should be publicisedand understood by those who work in sensitive areason Bryher.Slow worms Anguis fragilis have been introduced to Bryher. Photo: Ge<strong>of</strong>frey Jones<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 45 Marine Reptilia – Sea TurtlesOverviewAll seven species <strong>of</strong> sea turtle are globally threatenedand most are migratory, <strong>of</strong>ten travelling hugedistances across open water. Only female adultsreturn to the land to lay eggs, the rest <strong>of</strong> their lifecycleis pelagic. Previously, occasional sightings <strong>of</strong> turtlesaround the coast <strong>of</strong> Britain were treated as thoughthese were lost individuals which had strayed <strong>of</strong>fcourse. Now, for leatherbacks and possibly loggerheadturtles it is accepted that our waters are an importantpart <strong>of</strong> their range.Leatherback Dermochelys coriacea, Kemp’s ridleyLepidochelys kempii and loggerhead turtles Carettacaretta have been recorded around <strong>Scilly</strong>. All marineturtles are on the IUCN red list <strong>of</strong> threatened species.Important AreasExcept for strandings, sea turtle sightings are generally<strong>of</strong>fshore, <strong>of</strong>ten in deeper water. Leatherback turtlesfeed in the water column on schools <strong>of</strong> jellyfish,individuals <strong>of</strong> this species have been recordedtravelling over 5000 kilometres and they are thoughtto be nomadic rather than migratory. <strong>The</strong> first knownrecord from <strong>Scilly</strong> is from 1916 when a leatherbackwas found caught in an antisubmarine net south <strong>of</strong> theBishop Rock (Penhallurick, 1982)Loggerhead turtles are occasionally seen around <strong>Scilly</strong>(Penhallurick, 1982).<strong>The</strong>re is one definite record <strong>of</strong> aKemp’s ridley turtle in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> from 1925.This is the World’s rarest sea turtle and its range doesnot normally extend this far north.Species <strong>of</strong> Flora and Fauna (CITES) 1975, AppendixII <strong>of</strong> the Bern Convention 1979, Appendices I and II<strong>of</strong> the Bonn Convention 1979 and Annex IV <strong>of</strong> theEC Habitats Directive. <strong>The</strong> loggerhead is also listedas a priority species on Annex II <strong>of</strong> the EC HabitatsDirective. All sea turtles are protected under Schedule5 <strong>of</strong> the <strong>Wildlife</strong> and Countryside Act 1981 and theConservation (Natural Habitats & c.) Regulations 1994.Trends and IssuesResearch<strong>The</strong>re is a sea turtle research group at ExeterUniversity’s <strong>Cornwall</strong> Campus although none <strong>of</strong> theircurrent research is specifically on turtles in <strong>Scilly</strong>.Strandings and sightings records are collected by SeaQuest South West, the <strong>Cornwall</strong> Marine StrandingsNetwork and the Marine Conservation Society.ThreatsTurtles are most at risk when they are outside UKwaters, particularly when the females come ashoreto lay eggs and in countries where they are takenfor meat and shells. As these species are migratorytheir conservation has to be at a global level to ensuresuccess. Other threats include coastal developmentaround nesting beaches, egg predation, pollution andcollision with boats.<strong>The</strong> main threat to sea turtles in UK waters is the risk<strong>of</strong> ingestion <strong>of</strong> plastic litter such as plastic bags whichcan be mistaken for jellyfish. Accidental entanglementin fishing gear is also a major threat to these airbreathing species.Conservation ImportanceGlobally all sea turtles are considered threatened but itis hard to assess their conservation status in UK watersbecause they are rarely sighted and difficult to study.Leatherback turtles are the largest species <strong>of</strong> seaturtle and also the most commonly sighted species inBritish waters, travelling huge distances to feed on thejellyfish blooms which occur here. Leatherbacks areclassed as Critically Endangered.Loggerhead and Kemp’s ridley turtles are warmwater species and, when seen in UK waters, are<strong>of</strong>ten juveniles which are thought to have strayed <strong>of</strong>fcourse by accident. <strong>The</strong> possible exception to this isloggerheads which may be at the northern limit <strong>of</strong>their range in our waters.All sea turtles are national BAP species and aremanaged under a grouped species action plan formarine turtles, led by the Marine Conservation Societyand the Herpetological Conservation <strong>Trust</strong>.All sea turtle species are listed on Appendix I <strong>of</strong> theConvention on the International Trade in EndangeredLeatherback turtles Dermochelys coriacea are occasionally sightedaround the islands. Photo: Mike Daines<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 46 BirdsOverviewSeabirds<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s maritime influence makes it animportant place for seabirds, with the islands beingdesignated in 2001 as a Ramsar site for their breedinglesser black-backed gulls Larus fuscus (4% <strong>of</strong> the UKpopulation, 3% <strong>of</strong> the W Europe/Med/W Africa) andas a Special Protection Area (SPA) in 2001 for theirpopulation <strong>of</strong> European storm-petrels Hydrobatespelagicus (7% <strong>of</strong> the European storm-petrels in the UKbreed in <strong>Scilly</strong>). Other seabirds found here includeroseate tern Sterna dougallii, a very rare breedingspecies in Britain. It was a former breeding species in<strong>Scilly</strong> but has not bred since about 1994 and is nowa scarce summer visitor. Small numbers <strong>of</strong> commonterns Sterna hirundo breed here, this being an Annex IIspecies on the EU Habitats Directive.Terrestrial birds<strong>The</strong> small size <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> means that thepopulations <strong>of</strong> the resident terrestrial birds arenecessarily low, but some <strong>of</strong> them are at particularlyhigh densities. Species such as the song thrush Turdusphilomelos, a species <strong>of</strong> conservation importancedue to its significant population declines over thepast century in Britain, are found in relatively largenumbers here.Passage birds<strong>Scilly</strong> is notable for the number <strong>of</strong> migratory birds thathave been recorded here. <strong>The</strong> species list for the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> is one <strong>of</strong> the highest for any part <strong>of</strong> Britain.However, many <strong>of</strong> the birds have only been recordedas rare visitors, including a high proportion whichmay be described as vagrants.Important AreasMany <strong>of</strong> the islands <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are importantsites for breeding seabirds. Of particular note areSamson, which is noteworthy for lesser black-backedgull and Annet, which is noteworthy for Europeanstorm-petrel. Despite the importance <strong>of</strong> the individualsites, it is critical to recognise the significance <strong>of</strong> all theseabird breeding sites as a single system.Conservation Importance<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are internationally important for aseabird assemblage <strong>of</strong> more than 20 000 birds and inparticular for breeding lesser black-backed gull andEuropean storm-petrel<strong>The</strong>y are nationally important for European shagPhalacrocorax aristotelis (3% <strong>of</strong> UK population) andgreat black-backed gull Larus marinus.Common tern Sterna hirundo, roseate tern S.dougallii,sandwich tern S. sandvicensis and Arctic tern S.paradisaea have all bred here. Common terns are theonly species that regularly breed at present with about80 pairs at several sites. This is the only site for roseateterns west <strong>of</strong> Dorset, but they have not bred for over adecade.Balearic shearwater Puffinus mauretanicus, a CriticallyEndangered species, spends some <strong>of</strong> the year in smallnumbers in the waters <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Atlantic puffins Fratercula arctica, because <strong>of</strong> theirengaging appearance, are probably the most noticeablebreeding seabird to the general public and could beused as a flagship species. <strong>The</strong>re are very few coloniesin England and the population in <strong>Scilly</strong> has fallen overthe last century from many thousands to only about ahundred.Song thrushes Turdus philomelos occur at high densities in <strong>Scilly</strong> and are very tame. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 47

Lesser black-backed gulls Larus fuscus; 4% <strong>of</strong> the UK population breed in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. Photo: Rosemary Parslow<strong>The</strong>re are 45 species on the BAP priority list, but only12 <strong>of</strong> those species might be considered to be at alldependent on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> for their survival andonly seven <strong>of</strong> them breed there:Herring GullCommon CuckooDunnockSong ThrushCommon StarlingHouse SparrowCommon LinnetLarus argentatusCuculus canorusPrunella modularisTurdus philomelosSturnus vulgarisPasser domesticusCarduelis cannabina<strong>The</strong> song thrush, which in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is verytame and occurs in very high densities, is arguably themost significant <strong>of</strong> these due to that fact. Herring gull,dunnock, common starling and house sparrow are alsopresent in good numbers.<strong>The</strong> common ringed plover Charadrius hiaticula breedsin small numbers on shingle. <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> areone <strong>of</strong> a handful <strong>of</strong> sites in the south-west where theybreed, none <strong>of</strong> which are in mainland <strong>Cornwall</strong>.Trends and IssuesResearchAs part <strong>of</strong> the SPA all breeding seabird species areregularly monitored by the RSPB and NE. <strong>The</strong> <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong> monitor all breeding birds onAnnet annually apart from burrowing species. <strong>The</strong>RSPB also conduct productivity monitoring <strong>of</strong> certainspecies such as kittiwakes Rissa tridactyla.Ongoing studies into the seabird populations,particularly the terns, may clarify why their breedingsuccess is relatively poor.Robinson carried out surveys <strong>of</strong> the song thrush forseveral years in the late 1990s to early 2000s, this dataprovides a baseline for this species. Further study <strong>of</strong>the song thrush in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> might clarify whyit occurs at high densities there, but is in decline inmuch <strong>of</strong> the rest <strong>of</strong> Britain.Fisheries ImpactsSome diving birds such as European shags can becaught in gill-nets. <strong>The</strong> impact on local populations iscurrently thought to be minimal.PredatorsRats are a significant problem in relation to breedingseabird productivity at certain sites. A strategy toremove rats from the <strong>of</strong>f-islands has been successful,but needs to be monitored and if need-be, continued.TourismHuman disturbance affects the breeding success <strong>of</strong>certain breeding species such as common tern andcommon ringed plover.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 48 Terrestrial MammalsOverview<strong>The</strong> terrestrial mammals include rodents, bats andlarger species, such as deer.Generally speaking mammals are ubiquitous inBritain, but the isolation <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> meansthat the number <strong>of</strong> terrestrial mammals that have beenrecorded there is very small (only 10 are certain) andsome <strong>of</strong> those have been introduced.However, there are at least four species <strong>of</strong> batsrecorded for the islands, two <strong>of</strong> which (commonand soprano pipistrelle Pipistrellus pipistrellus and P.pygmaeus) are considered to be resident.Important AreasAmong the small number <strong>of</strong> terrestrial mammals, onlythe bats are particularly site dependent and coupledwith the fact that they are <strong>of</strong> conservation concern alltheir breeding and roosting and sites are significant.Conservation ImportanceAll British bat species and their roosts are protectedby the <strong>Wildlife</strong> and Countryside Act 1981; hedgehogsare also partially protected by this act. Of the eleventerrestrial mammal species in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, threeare on the BAP priority list, one <strong>of</strong> which has beenintroduced. <strong>The</strong>y are:(introduced) West European HedgehogErinaceus europaeusNoctuleNyctalus noctulaSoprano Pipistrelle Pipistrellus pygmaeus<strong>The</strong> <strong>Scilly</strong> shrew Crocidura suaveolens cassiteridum, asubspecies <strong>of</strong> the Continental lesser white-toothedshrew which is found only in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> inBritain is significant because <strong>of</strong> that fact.Trends and IssuesResearchMore research is required in order to fully assessthe status <strong>of</strong> the various bat species within the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong>. In particular, all the nursery roosts andhibernacula need to be identified.Loss <strong>of</strong> HabitatA number <strong>of</strong> bat roosting sites and/or hibernaculahave been destroyed in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in the past.Nearly all <strong>of</strong> the destruction has occurred because <strong>of</strong>the demolition or refurbishment <strong>of</strong> buildings.AgricultureSome agricultural operations, particularly the use <strong>of</strong>pesticides, may affect bat populations by reducingtheir food supply – there is evidence <strong>of</strong> pesticidepoisoning <strong>of</strong> a single pipistrelle in the past, thoughsome <strong>of</strong> the chemicals are no longer in use.Public AwarenessAn <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Bat Group which is affiliated to theIoSWT has been set up with the aim <strong>of</strong> training morelocal people to be bat wardens.Wider public understanding <strong>of</strong> the small number<strong>of</strong> mammals that are found in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>,including their status and legal protection, would beadvantageous. In particular, the law relating to batsneeds to be widely recognised.<strong>Scilly</strong> shrew Crocidura suaveolens cassiteridum is a sub-species found only in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. Photos: David Mawer and Ben Lascelles<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 49 Marine mammals – whales,dolphins, porpoises and sealsOverview<strong>The</strong> marine mammals <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> includelarge and small cetaceans (whales, dolphins andporpoises) and also seals. <strong>The</strong>se charismatic andpopular species are important to the economy <strong>of</strong> theislands for tourism and play important roles in marineecosystems.Cetaceans are divided into baleen whales (Mysticeti),which use plates <strong>of</strong> baleen to filter out food from thewater column and toothed whales (Odontoceti) whichhave teeth. Dolphins and porpoises are included in theOdontoceti.As an oceanic archipelago, <strong>Scilly</strong> is visited by oceanicand coastal marine mammals. Some cetaceans areknown here only from records <strong>of</strong> a single stranding,while for others the waters around the islandsrepresent an important habitat. All cetaceans usingthese waters are so mobile that the waters around<strong>Scilly</strong> only represent part <strong>of</strong> their home ranges (N.Tregenza, pers. comm.).Grey seals Halichoerus grypus are one <strong>of</strong> the bestknown species that wildlife lovers associate with the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong>y congregate in one area to mate anduse known breeding areas where they are able to ‘haulout’ on the rocks. <strong>Scilly</strong> is therefore an important sitefor breeding seals. Satellite tracking <strong>of</strong> grey seals hasshown that they forage over very large distances andtagging shows that seals from Brittany and Wales visitthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> at times (Westcott, 1993).<strong>The</strong> grey seal population in <strong>Scilly</strong> is about 350 strongand is resident there throughout the year althoughsome individuals may travel between <strong>Scilly</strong> and themainland (Lambert, 2000).Cetaceans are <strong>of</strong>ten seen by passengers on the RMVScillonian passenger ferry as they travel between StMary’s and Penzance. Harbour porpoises Phocoenaphocoena are frequently sighted when the water is calmenough for their small dorsal fins to be visible as theybreak the surface, and may live there throughout theyear. Several different species <strong>of</strong> dolphin includingbottlenose dolphins Tursiops truncatus and commondolphins Delphinus delphis are seen regularly,particularly in the summer months when many boatusers are out on the water.Important AreasMost cetacean sightings records for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>are to the south <strong>of</strong> the Islands around Bishop’s RockLighthouse, Poll Bank and Giants Castle but this maysimply reflect the fact that there are more birding andfishing boat trips in this area.<strong>The</strong> population <strong>of</strong> grey seals is distributed betweenthe Eastern <strong>Isles</strong>, the Norrad Rocks and the WesternRocks.Conservation ImportanceAll cetaceans are BAP species, managed by a groupedspecies plan. Cetaceans are protected by the BernConvention (1979) which is implemented in the UKthrough the <strong>Wildlife</strong> and Countryside Act (1981). <strong>The</strong>yare also covered by the Bonn Convention (1979) whichprotects migratory species.<strong>The</strong> harbour porpoise used to be seen daily inScillonian waters until the 1950s. <strong>The</strong>y are still seen in<strong>Scilly</strong> in the calmer summer months and but they arefar less common than they were in the past.Common dolphins prefer deep water and areoccasionally sighted <strong>of</strong>f the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong>y are theBottlenose dolphins Tursiops truncatus are occasionally observed in the waters around <strong>Scilly</strong>. Photo: Frank Gloystein<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 50

commonest species <strong>of</strong> dolphin in the southwest region(Evans, 1996).Striped dolphins Stenella coeruleoalba prefer deep waterand are infrequently sighted in Scillonian waters.Bottlenose dolphins are thought to exist in bothinshore and <strong>of</strong>fshore populations in this region. <strong>The</strong>inshore forms are more likely to be sighted around<strong>Scilly</strong>. Sightings <strong>of</strong> this species are infrequent, theremay once have been a permanent population herebut this would now only be elucidated through asurvey <strong>of</strong> elderly Scillonian residents. A small group<strong>of</strong> inshore bottlenose dolphins uses the inshore waters<strong>of</strong>f <strong>Cornwall</strong> and Devon and have also been observed<strong>of</strong>f the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. Some static nets such as gill andtangle nets pose a major threat to the survival <strong>of</strong> thisgroup (N. Tregenza, pers. comm.).Minke whales Balaenoptera acutorostrata, killer whalesOrcinus orca and pilot whales Globicephala melasare rarely sighted <strong>of</strong>f the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> (SeaquestSouthwest, Marine sightings database).Risso’s dolphins Grampus griseus occur occasionally,with several sightings <strong>of</strong> pods in 2007 (A Hicks, pers.comm.). One fin whale Balaenoptera physalus wasstranded in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in 1917 and this speciesis considered rare although numbers are thoughtto be increasing and more sightings are now beingreported around the Cornish coast (N. Tregenza, pers.comm.) and possibly also around <strong>Scilly</strong>. <strong>The</strong> spermwhale Physeter macrocephalus too is only known froma stranding in 1967 and is generally a rare species thatoccurs <strong>of</strong>f the edge <strong>of</strong> the continental shelf (<strong>Cornwall</strong><strong>Wildlife</strong> <strong>Trust</strong> Marine Strandings Network).Grey seals are an Annex II species in the EU habitatsdirective but are not a UK <strong>Biodiversity</strong> Action Planspecies. As high level predators, a healthy sealpopulation is a good indicator <strong>of</strong> the health <strong>of</strong> themarine environment in general.Unlike most British wildlife, seals have their own Act<strong>of</strong> Parliament, the Conservation <strong>of</strong> Seals Act, 1970.Nationally, grey seal populations have been steadilyincreasing since recording began in the 1960s. This islikely to be attributable to lower levels <strong>of</strong> hunting andchanges in rural economy. Current indications arethat this upward population trend is now levelling <strong>of</strong>f(Marine Conservation Society, 2007).This small, stable population breeds in the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> with pups appearing between August andOctober (Westcott, Parslow, 2007). Although theyare a small proportion <strong>of</strong> the estimated 123 000 greyseals in the UK, 90% <strong>of</strong> the UK’s seal population isin Scotland which makes the seals in <strong>Scilly</strong> relativelyimportant for this area <strong>of</strong> the country. <strong>The</strong> Scillonianpopulation accounts for about 40% <strong>of</strong> the pups born inthe southwest region (Duck, 1996). Furthermore theyare a key tourist attraction and a charismatic speciesfor which the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are famed. <strong>The</strong> presence<strong>of</strong> grey seals is a qualifying feature, although not aprimary reason, for selection <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> as aSpecial Area <strong>of</strong> Conservation.<strong>The</strong> predictability <strong>of</strong> seal sightings has meant thata seal watching and seal snorkelling industry hasdeveloped in <strong>Scilly</strong>. In the past the seals were viewedas a nuisance and were eaten and used to makecandles and for their hides. Fishing trips to watch sealsGrey seals Haliochoerus grypus are a species that is symbolic <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> for many people. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 51

first started in <strong>Scilly</strong> in the 1930s. In the 1960s and70s there was a government sponsored cull <strong>of</strong> sealsin the UK to protect fishing interests. Today there isstill some conflict between the interests <strong>of</strong> fishermenand tour boat operators but since the Conservation<strong>of</strong> Seals Act, 1970 it is illegal to kill seals without alicence during the closed season (for grey seals thisis 1st September to 31st December) or using certainmethods.<strong>The</strong>re have been several reliable sightings <strong>of</strong> commonseals Phoca vitulina, a BAP species, in <strong>Scilly</strong>, althoughthis species does not breed there and these individualsare outside their normal range.Trends and IssuesFifty years ago there was a decline in the sightings <strong>of</strong>small cetaceans and this was marked in <strong>Scilly</strong>. Olderboatmen in <strong>Scilly</strong> unanimously say that harbourporpoises were sighted almost daily in the past.Recently, sightings have declined but they are stillcommonly seen in summer months.Some <strong>of</strong> the large baleen whales, such as the bluewhale Balaenoptera musculus are so rare globally thatit is very difficult to say whether British waters andspecifically the waters around the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> arepart <strong>of</strong> their home range. It is likely that they wereonce here but their ranges have contracted due towhaling. Some <strong>of</strong> these species are only known herethrough a single stranding record. Fin whales arebeginning to recover from whaling and have recolonisedCornish waters. In recent years they havebeen observed feeding around <strong>Cornwall</strong> now eachwinter (N. Tregenza, pers. comm.).Research<strong>The</strong> <strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong> Marine StrandingsNetwork has representatives in <strong>Scilly</strong> who recordstrandings (dead and alive) <strong>of</strong> large marine animalssuch as cetaceans and seals.As a feature <strong>of</strong> the Special Area <strong>of</strong> Conservation, greyseals must be monitored a minimum <strong>of</strong> once every sixyears by Natural England.Fisheries ImpactsCetaceans and seals are vulnerable to entanglementin fishing gear. Investigation <strong>of</strong> cetacean strandingssuggests that certain static nets such as gill andtangle nets account for a high proportion <strong>of</strong> thecetacean strandings around the Southwest <strong>of</strong> England(<strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong> Marine Strandings Network2005 & 2006). <strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong>’s research hasshown that there is a significant level <strong>of</strong> bycatch <strong>of</strong>porpoises in the Celtic Sea hake fisheriesPelagic and demersal trawl fisheries also lead to acertain level <strong>of</strong> cetacean bycatch. For example commondolphins are regularly killed in pelagic pair trawlingfor sea bass (Jones et al, n.d.). Fisheries also competewith many marine mammals for food, removing fishfrom the area. Marine mammals can be disturbed andeven injured by underwater sounds from fishing andother industries (Evans, 1996).Seals in <strong>Scilly</strong> are sometimes sighted with fishingnet entangled around them (A. Hicks, pers. comm.).It is <strong>of</strong>ten not possible to intervene to remove thisnetting and the impacts upon individuals and thepopulation as a whole are unknown. Historically therehas been conflict between fishermen and seals, whichare seen as competing for the same resource. <strong>The</strong>reis some evidence that this conflict continues and thesuggestion that some fishermen still kill ‘nuisance’seals.PollutionCertain pollutants such as organochlorines andheavy metals can accumulate up the food chain andreach high levels in cetaceans and seals. Veterinaryassessment <strong>of</strong> the relationship between organochlorineburdens and morbidity show that all the smallcetaceans in Cornish waters are likely to be affectedand the control <strong>of</strong> organochlorines has been a majorand extremely valuable element in their conservation(N. Tregenza, pers. comm.).Seals are particularly vulnerable to accumulations<strong>of</strong> lead and mercury (Duck, 1996). Oil spills can beharmful to marine mammals, especially seals dueto fouling <strong>of</strong> their fur and inhalation <strong>of</strong> volatilecompounds; pups are particularly vulnerable to oilspills.TourismGrey seals are probably the single most importantspecies for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> in terms <strong>of</strong> tourism. <strong>The</strong>reare regular boat trips to observe, snorkel and dive withthe seals. <strong>The</strong>ir presence is reliable as a basis for boattrips, unlike other species which can not always be‘guaranteed’. According to Stephen Westcott, who hasstudied seals in <strong>Scilly</strong> for over 20 years, seals’ reactionto disturbance relates to which site they are at.DiseaseOutbreaks <strong>of</strong> Phocine Distemper Virus have hadsevere impacts on populations <strong>of</strong> common seals in thepast. Grey seals can catch the virus but are unlikely todie from it.StormsEvery year seal pups get washed <strong>of</strong>f the rocks,particularly during bad weather. Some are sent toGweek Seal Sanctuary but there are also fatalities.Breeding occurs at a stormy time <strong>of</strong> year (Parslow,2007).<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 52

Habitat Areas -An IntroductionSt Mary’s (650ha)As the largest island in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, St Mary’s isthe centre <strong>of</strong> life in <strong>Scilly</strong> with the main town, HughTown and main harbour. A large part <strong>of</strong> the island isfarmland, both arable and grassland. <strong>The</strong>re are areas<strong>of</strong> maritime heathland and coastal grassland alongthe undulating and varied coastline. At Higher Moorsis an area <strong>of</strong> wetland and open water separated by abar from a deep inlet. A stream from Holy Vale runsthough narrow woodland to feed the wetland. Asimilar wetland at Lower Moors and wet grasslandnear Porthloo extend across the island from west toeast. <strong>The</strong> coastline includes the large promontory withthe Garrison above Hugh Town, dunes, sandy androcky beaches and cliffs. <strong>The</strong>re are also three smallislets just <strong>of</strong>fshore.<strong>The</strong> Off Islands<strong>The</strong> other inhabited islands are Tresco (297ha), StMartin’s & White Island (238ha), Bryher (133 ha), StAgnes & Gugh (144ha). All have small populations <strong>of</strong>islanders living in small hamlets and they mainly rely<strong>of</strong> farming, fishing and to a large extent, tourism.Tresco is the most wooded island with plantationwoodland and rhododendrons through the middle<strong>of</strong> the island where the kilometre long Great Poolalmost cuts the island in two. Just north <strong>of</strong> Great Poolis mainly farmed, and beyond that ‘waved’ heathlandon the higher ground <strong>of</strong> Castle Down. In the south <strong>of</strong>the island are the ‘sub-tropical’ Abbey Gardens, AbbeyPool, extensive dune grassland and dunes with astrange flora alien plants among the native vegetation.Save for the farthest north most <strong>of</strong> the coast is dunesand sandy beaches.Bryher faces Tresco across a shallow channel. It hasa s<strong>of</strong>t sandy east coast that contrasts with the moreexposed west with its rocky bays. <strong>The</strong> island is slightlyhilly with a central plain and saline pool. <strong>The</strong> hills areheathy, with more coastal grassland and heathlandtowards the very exposed promontory <strong>of</strong> ShipmanHead in the north.St Martin’s has a west-east alignment and has longsandy beaches and extensive sand flats to the south.Farmland forms the backbone <strong>of</strong> the island with acharacteristic pattern <strong>of</strong> small fields at Higher Townmost <strong>of</strong> which are formed from blown sand. Along thenorth <strong>of</strong> the island is a band <strong>of</strong> coastal grassland andheathland right up to the cliffs below Chapel Down inthe east.St Agnes is separated from the main group <strong>of</strong> islandsby a deep channel. It has a coastland <strong>of</strong> small rockyor sandy bays. <strong>The</strong> centre <strong>of</strong> the island is farmed withmany very small fields with green fences. <strong>The</strong>re is alarge freshwater pool and surrounding meadow inthe north <strong>of</strong> the island and important heathland areason Wingletang Down in the south and linked (by atombolo) to the rocky, heathy island <strong>of</strong> Gugh.Annet (22ha)Well–known for its colonies <strong>of</strong> Manx shearwaters,puffins and storm petrels, Annet is a low-lying islandwith dramatic carns (tors) at its extremities. Much<strong>of</strong> the island has unusual vegetation cover <strong>of</strong> hugethrift tussocks and areas <strong>of</strong> bracken, sand sedge andYorkshire fog grasslands.Samson (36ha)Two hills joined by a sandy neck form the island.North Hill has a heathy top surrounded by densebracken. South Hill is mostly bracken with the ruins <strong>of</strong>the abandoned cottages and walls <strong>of</strong> the former deerpark.St Helen’s GroupNorthwethel, St Helen’s and Teän have all beeninhabited at some time. Round Island has been homeThrift Armeria maritima and lichen-encrusted boulders on the coast. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 53

to lighthouse keepers in the past before automation <strong>of</strong>the lighthouse. <strong>The</strong>y are quite varied in landscape withareas <strong>of</strong> heathland, dunes, grassland and both rockyand sandy beaches. St Helen’s and Teän have smallhills; Round Island has steep cliffs and the lighthouseon the summit. Teän is home to several rare plants andinvertebrates.Eastern <strong>Isles</strong>A group <strong>of</strong> a dozen or so small islands protectedwithin the circle <strong>of</strong> the rest <strong>of</strong> the islands. Generallythey have a well-vegetated and s<strong>of</strong>ter appearancethan the Western & Norrad Rocks. <strong>The</strong> larger islandssuch as Great Ganilly and the Arthurs have areas <strong>of</strong>heathland, coastal grassland and sandy bays. Seabirdsand Grey Seals have colonies on many <strong>of</strong> the islands.Western and Norrad Rocks<strong>The</strong>se are two groups <strong>of</strong> rocky and extremely exposedislands, stacks and reefs lying in the west <strong>of</strong> thearchipelago. Few <strong>of</strong> the islands support any highervegetation but many are important for their seabirdcolonies and seals.<strong>The</strong> following sections describe these priority habitats: Arable field margins2.2.2.2 Coastal sand dunes2.2.2.3 Coastal vegetated shingle2.2.2.4 Fragile sponge and anthozoanscommunities on subtidal rock2.2.2.5 Hedgerows and boundary features2.2.2.6 Intertidal boulders2.2.2.7 Lowland dry acid grassland2.2.2.8 Lowland heathland2.2.2.9 Lowland meadows2.2.2.10 Marine sand and gravel2.2.2.11 Maritime cliff and slopes2.2.1.12 Ponds2.2.1.13 Reedbeds2.2.1.14 Saline lagoons2.2.1.15 Seagrass2.2.1.16 Standing open water2.2.1.17 Tide-swept channels2.2.1.18 Wet woodlandTresco and Bryher showing a mosaic <strong>of</strong> marine, terrestrial and freshwater habitats. Photo: RNAS Culdrose SAR flight<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 54 Arable Field MarginsOverviewNationally arable wild flowers have declineddrastically both in abundance and distribution. In the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> some arable species formerly associatedwith cornfields that are declining on the mainland arestill relatively frequent. Some species have becomeparticularly associated with the cultivation <strong>of</strong> bulbfields especially those growing winter-floweringnarcissus. Recently there has been a decline in bulbfarming which is already having an effect on the flora<strong>of</strong> the bulb-fields.Distribution and Extent<strong>The</strong> small size <strong>of</strong> fields in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> has meantit is impossible to leave wide uncultivated marginsbetween the crop and the field boundary. But there isusually a narrow roughly half metre wide strip aroundthe crop where the arable weeds can flourish. Oftenthey can also grow within the crop. Two importantNVC plant communities OV2 Briza minor – Silenegallica and OV6 Cerastium glomerata – Fumaria muralisboraei are associated with bulb fields; the formercommunity has only been identified in <strong>Scilly</strong> and thesecond in both <strong>Scilly</strong> and West <strong>Cornwall</strong>. Many <strong>of</strong>the rare plants found in these communities are winterannuals so are disadvantaged by arable crops thatrequire spring cultivation.In the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> arable communities are foundon all the inhabited islands although the speciescomponent varies from island to island.Although fields in <strong>Scilly</strong> are not large enough forground-nesting birds to utilise they provide feedingsites for a range <strong>of</strong> birds.Seeding arable weeds attract large flocks <strong>of</strong> feedinglinnets and other finches.A number <strong>of</strong> rare arable plants are found in <strong>Scilly</strong>including shepherd’s needle Scandix pecten-veneris,small-flowered catchfly Silene gallica and westernfumitory Fumaria occidentale.Trends and Issues<strong>The</strong>re is a marked loss <strong>of</strong> bulb-fields in <strong>Scilly</strong> over thepast ten years. <strong>The</strong>re are probably less than half thefields growing bulbs there were 30 years ago.Many arable fields have been converted to grass.Other arable crops such as potatoes, green vegetablesand s<strong>of</strong>t fruit do not support the same range <strong>of</strong> arableplants.Some fields have been planted with ‘conservationcrops’ (<strong>The</strong>se are seed mixtures designed to beattractive to wildlife but <strong>of</strong>ten made up <strong>of</strong> a variety<strong>of</strong> plants frequently not native to the area or evento Britain) or quinoa; such crops do not supportpopulations <strong>of</strong> arable species.ResearchResearch and monitoring <strong>of</strong> arable plant communitiesand field margins associated with the bulb fieldsshould be a priority.Conservation ImportanceArable fields with assemblages <strong>of</strong> arable plants are<strong>of</strong> nature conservation value for butterflies, bees andother invertebrates.Western fumitory Fumaria occidentale a rare plant <strong>of</strong> arable field margins which is endemic to <strong>Scilly</strong> and <strong>Cornwall</strong>. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 55 Coastal Sand DunesOverviewCoastal sand dunes develop where there is a plentifulsupply <strong>of</strong> sand, beaches that dry out between tidesand there are onshore winds. Sand is sedimentarymaterial ranging in size from 0.2 to 2.0 mm. Formerly,the dry sand was blown inland and deposited abovehigh water mark all over the islands where it formeddeep deposits. In the past it was a great nuisance tohouseholders when the sand blew into their housesand submerged their fields. To stabilise the dunesthey were planted with mat-forming plants such ashottentot fig Carpobrotus edulis and marram Ammophilaarenaria. Now dune grasses and sand sedge Carexarenaria, which grow through the sand and bind ittogether, trap the sand and continue the process.Distribution and ExtentMost <strong>of</strong> the sand dunes in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are quitelow in form and do not produce the larger systemsseen elsewhere. Some have been pushed inland andflattened to form dune grasslands and subsequentlydune heath. Bar Point on St Mary’s is an example <strong>of</strong> aforeland dune and in other places are sand bars calledtombolos – the best example is the Gugh Bar betweenSt Agnes and Gugh. <strong>The</strong> largest dunes in <strong>Scilly</strong> areat Appletree Banks on Tresco, around St Martin’sand at Bar Point on St Mary’s. <strong>The</strong>re are lesser dunesand sandy beaches on many islands, especially thosesurrounding the central sand flats <strong>of</strong>f St Martin’s.Conservation ImportanceSeveral <strong>of</strong> the <strong>Scilly</strong> SSSIs include areas <strong>of</strong> sand duneor dune grassland. For example Rushy Bay on Bryher,Samson and Pentle Bay on Tresco.Trends and IssuesDune systems are fragile and easily damaged byvehicles or public use.When the surface <strong>of</strong> the dune is ruptured ‘blow-outs’can occur reducing the stability <strong>of</strong> the dune.Where dunes are the main coastal protection, stormsurges can break through and flood inland as well aswashing the dune away. This has happened in severalplaces –e.g. Higher Town Bay on St Martin’s.Hugh Town is partly built on a former dune; it hasbeen vulnerable in storms and needed considerablesea defence work.Sand dunes at Little Bay, St Martin’s. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 56 Coastal Vegetated ShingleOverviewShingle includes particles that range from 2mm to200mm, merging at one end into sand and at the otherinto cobbles. In many cases there are similarities inthe strandline vegetation <strong>of</strong> these beaches and sandybeaches although the amount <strong>of</strong> finer materials mixedin with the shingle, and the hydrological regime, forexample freshwater seepages can influence whichplants occur. <strong>The</strong> classic pioneer strandline plants in<strong>Scilly</strong> include sea kale Crambe maritima, very rarely seapea Lathyrus japonicus, frosted orache Atriplex lacinataand several other oraches Atriplex spp., sea beet Betavulgaris maritima and sea campion Silene uniflora; theseare all species that can withstand direct exposureto salt spray and even cope with storm conditions.Further from the shore, the strandline plants canmerge into more mixed and stable communities suchas coastal grassland.Shingle beaches may support breeding birds such asgulls, ringed plovers and terns. Where the shinglegives way to boulder beaches storm petrels maynest under the boulders. <strong>The</strong>re are also a number <strong>of</strong>characteristic invertebrates that are found on coastalshingle.Distribution and Extent<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have a number <strong>of</strong> shingle structuressuch as bars, raised beaches and shingle beaches. <strong>The</strong>shingle community SD1 is quite widespread in <strong>Scilly</strong>with examples from the Western Rocks, Annet, Eastern<strong>Isles</strong> and other islands. <strong>The</strong>se shingle beaches are animportant habitat, both for the plant communities, theinvertebrate populations and their use by birds andsealsConservation ImportanceCoastal vegetated shingle is a national BAP habitat.Shore dock Rumex rupestris was formerly found onshingle beaches in <strong>Scilly</strong> but has been largely lost fromthis habitat.Rarities include sea knotgrass Polygonum maritimum,sea pea Lathyrus japonicus and Ray’s knotgrassPolygonum oxyspermum rayii.Trends and Issues<strong>The</strong> shingle beaches are most under threat from sealevel rise and increased storminess. <strong>The</strong> loss <strong>of</strong> shoredock in some places can be related directly to erosionby storms.Shingle beaches are vulnerable to pollution, especiallyfrom oil spills.<strong>The</strong> shingle beaches are subject to massive amounts <strong>of</strong>plastic rubbish and non-biodegradable detritus frompassing shipping and from other sources.Shore dock Rumex rupestris grows on coastal vegetated shingle but has declined in <strong>Scilly</strong>. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 57 Fragile Sponge andAnthozoan Communities onSubtidal Rocky ReefsOverview<strong>The</strong> habitat ‘fragile sponge and anthozoancommunities on subtidal rock’ has been newlydesignated as a BAP habitat in 2007 and has not beenfully defined. However many subtidal reefs in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> appear to fit this category. <strong>The</strong> graniticreefs and islets surrounding the main islands havewalls covered with abundant anemones and s<strong>of</strong>tcorals (anthozoans). Particularly characteristic <strong>of</strong> thesewalls are jewel anemones Corynactis viridis, plumoseanemones Metridium senile and dead man’s fingersAlcyonium digitatum. <strong>The</strong>se colourful and spectacularcommunities are one <strong>of</strong> the main attractions for divingtourists. Close by, usually less exposed to the currentthere are <strong>of</strong>ten diverse communities <strong>of</strong> sponges suchas Axinella damicornis.Physically all <strong>of</strong> these species can be considered fragileas they would be easily damaged by mechanicalimpacts especially the branching sponges and corals,which are fragile due to their structure that protrudesfrom the rock face. Furthermore, species such as thepink sea fan have very slow growth rates thereforerecovery after damage is extremely slow. Overall thehabitat is sensitive to impacts and has a very slowrecovery rate.One <strong>of</strong> the three primary reasons that the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>were selected as a Special Area <strong>of</strong> Conservation is thepresence <strong>of</strong> reefs. Reefs are an Annex 1 (EU HabitatsDirective) habitat and they surround the islands,allowing the development <strong>of</strong> faunal communities suchas sponges and anthozoans.Distribution and ExtentRocky reefs are extensive around the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>,with over 100 reef sites which have been dived andprobably many others which remain unexploredto date (T. Allsop, pers. comm.). Where these reefsoccur below the kelp zone and experience the rightconditions such as strong currents and low sedimentloads they are likely to support this habitat.<strong>The</strong>se reefs occur outside the shelter <strong>of</strong> the ring <strong>of</strong>islands, for example sites such as Trenemene in theWestern Rocks, the Crim Rocks, the Gilstone near StMarys and Hard Lewis near St Martins. <strong>The</strong>se habitatshave not been mapped hence the full extent <strong>of</strong> thishabitat is currently unknown.Fragile sponge communities occur particularly on themore sheltered eastern sides <strong>of</strong> the islands in over 25m<strong>of</strong> water. <strong>The</strong>se typically include Axinella damicornis,A. dissimilis and Homaxinella subdola (B. Picton, pers.comm.)Conservation ImportanceThis habitat was recently selected as a BAP habitatand is still pending a full description. It was selectedon the basis <strong>of</strong> being a habitat for which the UK hasinternational obligations, a declining or at risk habitat,a functional habitat and for supporting key species(which are on the BAP priority species list).MarLIN (the Marine Life Information Network)classifies ‘Erect sponges, Pink Sea Fans and RossA scuba diver explores a reef wall. Photo: Frank Gloystein<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 58

Rocky reef with jewel anemones Corynactis vividis. Photo: Malcolm NimmoCoral on slightly tideswept moderately exposedcircalittoral rock’ as a highly sensitive habitat.Some areas <strong>of</strong> the BAP habitat ‘Fragile sponge andanthozoan communities on subtidal rock’ would fallinto this category. According to MarLIN this habitatis particularly sensitive to substratum loss, changesin salinity, physical disturbance, extraction and otherstressors.Subtidal rocky reefs are recognized as importantin the EU Habitats Directive and this has led to thedesignation <strong>of</strong> Special Areas <strong>of</strong> Conservation in theUK based on the presence <strong>of</strong> reefs. In the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong>, reefs are one <strong>of</strong> three key habitats which havetriggered the area’s selection as an SAC (the other twobeing ‘mudflats and sandflats not covered by water atlow tide’ and ‘sandbanks which are slightly coveredby seawater all the time’).Trends and IssuesResearchSeasearch volunteer divers have been conductingannual subtidal surveys since 2004. Many <strong>of</strong> the sitessurveyed are areas <strong>of</strong> rocky reef which support thishabitat. Some reef sites have been surveyed repeatedlyat yearly intervals. Surveyors record species presentand other features <strong>of</strong> the habitat with abundanceestimates for each species.<strong>The</strong> great wealth <strong>of</strong> knowledge <strong>of</strong> the local diveoperators should be recorded for scientific andeducational use. Photographic records collected overyears <strong>of</strong> diving need to be analysed and archived.Visiting divers should be urged to participate inmarine life recording schemes.Fishing impactsAlthough scallop dredging is restricted within fourmiles <strong>of</strong> the islands there is evidence that damagehas occurred to fragile sponge and anthozoancommunities as a result <strong>of</strong> this activity in the past.Fragile sponges are easily damaged by potting whichoccurs in these areas.SedimentationExcess sediment can be suspended in the watercolumn as a result <strong>of</strong> coastal development. Deposition<strong>of</strong> this silt can easily damage fragile spongecommunities.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 59 Hedgerows and BoundaryFeaturesOverview<strong>The</strong>re are virtually no true native hedgerows in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong> few hawthorn Crataegus monogynahedges that exist on St Mary’s are <strong>of</strong> little conservationinterest. Although not a BAP habitat there are anumber <strong>of</strong> different boundary features in the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong>.Stone ‘hedges’ come in three main types, dry-stonewalling (single leaved), ‘Cornish hedges’ (doubleleaved) and granite masonry (such as the Garrisonwalls). <strong>The</strong>n there are green ‘fences’ <strong>of</strong> various species<strong>of</strong> trees and shrubs, alien evergreen species such asAustralasian natives that were planted to protect thebulb fields. Elm Ulmus spp. hedges are more frequentthan hawthorn although they too suffer in exposedplaces and stay gnarled and low. In more shelteredsites the elms are able to grow into trees and on StMary’s for example form shelterbelts. On St Mary’sand Tresco there are also planted conifer windbreaks<strong>of</strong> Monterey pine Pinus radiata and lodgepole pineP.contorta. Boundaries with both stone hedges anda green fence alongside are very common on all theinhabited islands.Distribution and Extent<strong>The</strong>re are many kilometres <strong>of</strong> hedges and fences onall the inhabited islands. On the larger uninhabitedislands there are also relict stone hedges from formercultivations.Conservation ImportanceHedges play a role in enabling species to movethrough the landscape by connecting semi-naturalhabitats.Double-leaved or ‘Cornish hedges’ which have a soilcore between two courses <strong>of</strong> stone are an importancerefuge for many plants, particularly species such aswestern fumitory and ferns. <strong>The</strong>y are also refugesfor invertebrates - some are used as nesting sites bysolitary bees, and mammals including the <strong>Scilly</strong> shrew.Dry-stone or single-leaved hedges also supportpopulations <strong>of</strong> lichens, ferns and other plants andprovide shelter for mammals and invertebrates.<strong>The</strong> mortared walls also act as refuges to many plants.<strong>The</strong> tops <strong>of</strong> the Garrison walls for example have anunusual and rich flora. House sparrow and starlinguse crevices for nesting and it is suspected bats mayroost in walls sometimes.<strong>The</strong> evergreen fences are important sites for nestingbirds; song thrush, blackbird, linnet, dunnock andoccasionally by house sparrow.Trends and Issues<strong>The</strong> use <strong>of</strong> herbicides to clean stone hedges has led toloss <strong>of</strong> species.Neglect has led to bramble and bracken overwhelmingsome stone hedges.Neglect allows loose stones to fall, leading todisintegration and instability <strong>of</strong> stone hedges.Work is needed with the farming community to ensuresympathetic conservation <strong>of</strong> field boundaries.ResearchAn investigation could be made to determine thecomparative value <strong>of</strong> the green fences both as shelterand for nature conservation.Stone hedges on St Martin’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 60 Intertidal BouldersOverviewShores in <strong>Scilly</strong> range from the super-exposed to fairlysheltered and the intertidal boulders support differentspecies assemblages depending on the degree <strong>of</strong>exposure (Hiscock, 1985). <strong>The</strong> more exposed shores aretypically animal dominated whereas in embaymentsthe rocky shores are dominated by brown algae.Typical zonation <strong>of</strong> plant and animal communitiescan <strong>of</strong>ten be seen on the shorelines, from the brownalgae spiral wrack Fucus spiralis high up the shoredown to thong weed Himanthalia elongata on the lowershore. Kelp beds are present in boulder areas whichare only uncovered at low spring tides. Except for themost exposed shores the rocky shores in <strong>Scilly</strong> supportrich under-boulder communities (Parslow, 2007).Rockpools are present on some shores, their speciesassemblages reflect their position on the shore, withsome <strong>of</strong> the highest pools only being replenished atextreme high water spring tides.Distribution and extent<strong>The</strong>re are about 97km <strong>of</strong> rocky shore in <strong>Scilly</strong>(Parslow, 2007). Although some <strong>of</strong> this shoreline isrocky platforms or vertical or steeply sloping rock,much is intertidal boulders.Trends and IssuesResearchMany intertidal boulder areas are easily accessiblefor research activities. <strong>The</strong>re is a risk that manystudents carrying out fieldwork in the same area couldnegatively impact the habitat. <strong>The</strong> original bouldersurveys in <strong>Scilly</strong> for the Nature Conservancy Councilwere discontinued because they involved upturningboulders which was thought to impact the underbouldercommunities.PollutionIntertidal areas are at risk from oil spills andsubsequent clean up operations which could damageand destroy the intertidal boulder communities.EducationRockpools support miniature ecosystems and <strong>of</strong>tencontain a diverse range <strong>of</strong> species. <strong>The</strong> rocky shore isan ideal outdoor classroom where many ecologicalprinciples can be seen. <strong>The</strong>y provide an accessibleintroduction to the marine environment for schooland university students as well as for holiday-makersand the general public. This also has the potential todamage the habitat due to people moving boulders,especially if the activity is concentrated on certainparticularly accessible sites.Conservation ImportanceIntertidal boulders are a <strong>Biodiversity</strong> Action Planpriority habitat because the UK has internationalobligations to protect this habitat; the habitat is atrisk or in decline and is a functional habitat. Hiscock(1984) identified 9 different types <strong>of</strong> rocky shorewith different levels <strong>of</strong> exposure. A total <strong>of</strong> 128 algal,13 lichen and 237 macroscopic animal species wereidentified on the rocky shores.<strong>The</strong> intertidal boulders <strong>of</strong> <strong>Scilly</strong> are the nationalstronghold for the BAP species Paludinella littorina,the lagoon snail (Light and Kileen, 2001). <strong>The</strong> boulderhabitats on sheltered shores in <strong>Scilly</strong> are particularlyrich examples <strong>of</strong> their type and <strong>of</strong> high natureconservation interest (Fowler, 1991).Rocky intertidal areas are used as haul-out sites bygrey seals, which are a feature <strong>of</strong> the Special Area <strong>of</strong>Conservation.St Martin’s sedimentary shore is a designated Site <strong>of</strong>Special Scientific interest. This includes some areas <strong>of</strong>intertidal boulders but these are incidental as the mainpurpose <strong>of</strong> the designation was to protect the sandflats.Rockpools which form in areas <strong>of</strong> intertidal boulderssupport a diverse array <strong>of</strong> species and are importantfor juveniles <strong>of</strong> many fish and other species.Sand and boulders in the intertidal zone. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 61 Lowland Dry Acid GrasslandOverviewAcid grasslands occur over acid rocks such as thegranites that form the bedrock <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Although the habitat is typically species-poor severaldifferent NVC plant communities occur in <strong>Scilly</strong>.<strong>The</strong>se include the (U1)Festuca ovina - Agrostis capillaris- Rumex acetosella and (U4) Festuca ovina - Agrostiscapillaris - Galium saxatile grassland plant communities.Lowland acid grassland frequently occurs as anintegral part <strong>of</strong> lowland heath landscapes and oncoastal cliffs. It may be managed as pasture, grazed byrabbits or even wind-pruned in coastal areas.Acid grassland is characterised by a range <strong>of</strong> plantspecies such as heath bedstraw Galium saxatile,sheep’s-fescue Festuca ovina (frequently replaced in<strong>Scilly</strong> by red fescue F.rubra), common bent Agrostiscapillaris, sheep’s sorrel Rumex acetosella, sand sedgeCarex arenaria and tormentil Potentilla erecta. In placessome heathland plants such as ling Calluna vulgarismay occur within the grassland, but more commonlylowland acid grassland forms a mosaic with heathland(see lowland heathland, Section, especially incoastal situations. In many places acid grasslands canhave a high cover <strong>of</strong> bryophytes and acid grasslandcan be rich in lichens especially near the coast.Distribution and Extent.Figures for the amount <strong>of</strong> acid grassland in the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> are not known. But it occurs on all the inhabitedand larger uninhabited islands.Conservation ImportanceLowland dry acid grassland is a national BAP habitat.Trends and issues• Agricultural intensification, particularlyfertilisation and ploughing.• Lack <strong>of</strong> grazing or abandonment leading toinvasion by coarse grasses and bracken Pteridiumaquilinum.Lowland dry acid grassland at the coast on Gugh. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 62 Lowland HeathlandOverviewLowland heathland is a rare and threatened habitatnationally and internationally. <strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> haveareas <strong>of</strong> good quality lowland heathland on almostall the inhabited and larger uninhabited islands, alsoareas <strong>of</strong> more degraded heath on the inhabited islands.In the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> heathland is characterised by thepresence <strong>of</strong> dwarf shrubs such as ling Calluna vulgaris,bell heather Erica cinerea, common and western gorseUlex europaeus and U. gallii. Within the heathland areareas <strong>of</strong> taller and shorter vegetation, wet heath, bareground, temporary small pools and acid grassland.Within this habitat characteristic birds, invertebrates,vascular plants, bryophytes and lichens are found.In the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> the heathlands are mosaics<strong>of</strong> several different heathland plant communitiesincluding H7 Calluna vulgaris – Scilla verna heath,H8 Calluna vulgaris – Ulex gallii heathland, H10Calluna vulgaris – Erica cinerea heathland and H11Calluna vulgaris – Carex arenaria heathland and theacid grasslands U1 Festuca ovina – Agrostis capillaries– Rumex acetosella grassland & U4 Festuca ovina– Agrostis capillaris – Galium saxatile grassland). <strong>The</strong>yalso typically merge into cliff communities near thecoast. In more open places there are extensive areas <strong>of</strong>‘waved heath’ the product <strong>of</strong> extreme wind-pruningthat is very typical <strong>of</strong> the exposed ground in <strong>Scilly</strong>.Distribution and ExtentMost <strong>of</strong> the coastal areas on St Mary’s and the ‘<strong>of</strong>fislands’ have areas <strong>of</strong> heathland. In many cases there isa continuum with coastal grassland and maritime cliffcommunities.Heathland is otherwise mostly found on hilltops onthe uninhabited islands, notably North Hill, Samson,higher ground on Great Ganilly, Teän and St Helen’s.Conservation ImportanceLowland heathland is a national BAP habitat forbiodiversity conservation. <strong>The</strong> coastal heathlandcommunties, sometimes referred to as maritimeheathland (which on <strong>Scilly</strong> is a category that overlapswith lowland heathland and is characterised by theinfluence <strong>of</strong> salt spray), are nationally important withmany areas within SSSIs.Trends and IssuesAn unknown amount <strong>of</strong> heathland will have been lostto agriculture. Some was ploughed up in the 1950sand ‘60s to grow bulbs and potatoes. It is probablynot possible to determine how much, but remains<strong>of</strong> field boundaries are still evident in places. Some<strong>of</strong> this is now reverting to heathland when fields areabandoned.Lack <strong>of</strong> management and inappropriate managementis the most significant issue. Much heathland hasbecome invaded by bracken and common gorse.<strong>The</strong>re has been a diminution in the amount anddistribution <strong>of</strong> western gorse Ulex gallii that may havebeen due to burning.Formerly most heathland was grazed but this hasvirtually ceased on many heathland areas due to lack<strong>of</strong> stock. In the first half <strong>of</strong> the 20th century most farmsused horses and would have had a few cows. But nowthere are few farmers with any animals other thanthose who are specialising in dairy or beef cattle.Burning is used as a management tool but in manycases it has been accidental or casual withoutselectivity and targeting.<strong>The</strong> Waves <strong>of</strong> Heath project (2003-<strong>2008</strong>) is part<strong>of</strong> Tomorrow’s Heathland Heritage, a UK wideprogramme supported by the Heritage Lottery Fund.<strong>The</strong> Waves <strong>of</strong> Heath project aims to restore and bringinto appropriate management substantial areas <strong>of</strong><strong>Scilly</strong>’s maritime heathland and enhance people’senjoyment and understanding <strong>of</strong> heathland througheducation. Partners in the Waves <strong>of</strong> Heath project arethe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong>, Natural England, theDuchy <strong>of</strong> <strong>Cornwall</strong> and Tresco Estate.Waved heathland on St Martin’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 63 Lowland MeadowsOverview<strong>The</strong>se are lowland grasslands usually managed ashay meadows or pasture, excluding acid grasslandand maritime grasslands that are included elsewhere.In terms <strong>of</strong> National Vegetation Classification plantcommunities, they primarily embrace several types<strong>of</strong> grassland, particularly the MG5 Cynosurus cristatus- Centaurea nigra grassland. Although there werehay meadows in <strong>Scilly</strong> formerly, where these havesurvived they are now mostly used for livestockgrazing. Outside agricultural use these grasslands maybe found on places such as church-yards, roadsideverges and other localities, but generally mesotrophicgrassland is rare in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and althoughnone probably strictly conform to the BAP habitatdescription they are included here.Distribution and ExtentIn the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> this is a rare type <strong>of</strong> grassland;most grasslands are acidic although there are smallareas that are apparently derived from shell sand andsupport calcareous species, for example areas on thePlains on St Martin’s. A few fields on St Martin’s anda few verges and small areas on St Mary’s also aresomewhat closer to MG5. Whether these meadowsreflect a more neutral underlying soil or results fromformer management such as liming is unclear.Conservation ImportanceAlthough the amount <strong>of</strong> this type <strong>of</strong> grassland is smallit represents a habitat that has apparently been mainlylost from the islands and adds to the overall speciesdiversity.Trends and IssuesPloughing and re-seeding will change thesegrasslands, as would use <strong>of</strong> fertiliser.This is a generally under-recognised habitat in the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong>.Some <strong>of</strong> the grassland areas provide feeding areasfor birds and are attractive to butterflies and otherinvertebrates.<strong>The</strong> Plains on St Martin’s are derived from shell sand and support calcareous species. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 64 Marine Sands and GravelsOverview<strong>The</strong> intertidal and subtidal sand flats <strong>of</strong> the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> are extensive and nationally important dueto the diversity <strong>of</strong> their associated fauna. <strong>The</strong>y arecomprised <strong>of</strong> two habitats listed on Annex I <strong>of</strong> the EUHabitats directive and are the main features whichhave triggered the selection <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> as aSpecial Area <strong>of</strong> Conservation:· Mudflats and sandflats not covered by water atlow tide· Sandbanks which are slightly covered byseawater all the timeSubtidal sands and gravels are a national <strong>Biodiversity</strong>Action Plan habitat.<strong>The</strong> intertidal and subtidal sandy sediment areas arecontiguous within the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and are thereforestructurally and functionally linked – they are beingconsidered together in this document. <strong>The</strong>se areas areunusual due to their remoteness from most humanimpacts and from sources <strong>of</strong> freshwater. <strong>The</strong> sedimentis derived from granite and is coarse grained, evenin sheltered areas; the sands have low silt content asthere is very little input <strong>of</strong> alluvial sediment and lowlevels <strong>of</strong> pollution.Stable sediment areas support a rich infauna <strong>of</strong>burrowing invertebrates such as worms, bivalvemolluscs, urchins and anemones as well as mobilefauna like shrimps, crabs and fish. <strong>The</strong> presence <strong>of</strong>coarser material such as pebbles and cobbles provideshabitat for epifauna including algae, bryozoans,hydroids and ascidians. In shifting sediments speciesrichness and diversity is reduced but there may still becommunities <strong>of</strong> amphipods and other mei<strong>of</strong>auna.Distribution and Extent<strong>The</strong> largest and most important areas <strong>of</strong> intertidal andsublittoral sandy sediments are between the islands,extending from the beaches gradually into deeperwater, bisected by narrow tidal channels. This areaprotected by the surrounding islands and is thereforesheltered from high wave action. Large areas <strong>of</strong> sandflats are visible at low water, particularly south <strong>of</strong> StSandflats at Samson – the remains <strong>of</strong> old field margins are visible on the sand. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 65

Martin’s; east <strong>of</strong> Samson; between Bryher and Tresco(Tresco flats) and adjacent to Old Grimsby on Tresco.<strong>The</strong> largest <strong>of</strong> these is St Martin’s flats, a SSSI south <strong>of</strong>St Martin’s.<strong>The</strong> extent <strong>of</strong> the sandflats can be seen on nauticalcharts <strong>of</strong> the area. Much <strong>of</strong> the s<strong>of</strong>t sediment is coveredby seagrass beds and these areas have been mapped.Conservation ImportanceBoth the intertidal sandflats and the subtidalsediments are <strong>of</strong> European and National significancebecause <strong>of</strong> their extent and the richness and diversity<strong>of</strong> their associated communities (Natural England,Natural Area Pr<strong>of</strong>ile). <strong>The</strong>y support species whichare normally restricted to the subtidal, possiblyowing to unusual coarse quartz sediments foundhere in the intertidal (Brown et al, 1997). Variationsin wave exposure and tides in different areas haveled to increased species diversity within the sand andgravel communities; rocky outcrops and reefs withinsandy areas also enhance overall diversity. <strong>The</strong>re aresubstantial differences between the communities <strong>of</strong>each <strong>of</strong> the major sedimentary flats resulting fromdifferences in physical and biotic factors (Nichols andHarris, 1982).Sublittoral sands and gravels are a national BAPhabitat and a Habitat Action Plan has been produced.<strong>The</strong> shallow sublittoral and interlittoral sedimentssupport some <strong>of</strong> the most extensive and welldeveloped areas <strong>of</strong> seagrass beds in the UK. Seagrassbeds are a BAP habitat themselves and are consideredseparately within this document [Section].<strong>The</strong> area <strong>of</strong> intertidal sand flats adjacent to the island<strong>of</strong> St Martin’s has been protected as a Site <strong>of</strong> SpecialScientific Interest (SSSI number 2000168) since 1996.<strong>The</strong>se and other sand flats throughout the archipelagosupport aggregations <strong>of</strong> Ensis spp (razorshells) andEchinocardium cordatum and Spatangus purpureus (bothheart urchins), the latter is never usually found in theintertidal elsewhere in the UK, tending to live onlyin sublittoral areas (Natural England, Natural AreaPr<strong>of</strong>ile). In some areas such as Old Grimsby Harbour,Tresco, the density <strong>of</strong> Echinocardium cordatum is upto 25 per square metre (Nichols and Harris, 1982).<strong>The</strong> razorshell Ensis siliqua biotope is nationallyuncommon but is widespread in <strong>Scilly</strong>. Densepopulations <strong>of</strong> burrowing anemones occur on some <strong>of</strong>the sand flats, especially in scoured channels which donot fully drain at low tide (Nichols and Harris, 1982).In areas where the sand is mixed with gravel, pebblesand cobbles there are faunal communities livingon the stones in addition to the subsurface infauna.<strong>The</strong>se areas generally occur between the islandswhere exposure and tidal influence are greater. <strong>The</strong>communities include nationally rare species such asthe red seaweeds Cruoria cruoriaeformis (A UK BAPspecies), Gelidiella calciocola and Schmitzia hiscockiana.<strong>The</strong>se stony areas may also support large populations<strong>of</strong> the gastropod Gibbula magus, at population densities<strong>of</strong> up to 40 per square metre (Nichols and Harris,1982).Some southern (Mediterranean – Atlantic) species,rarely recorded in UK waters are present in the sandysediment areas <strong>of</strong> <strong>Scilly</strong> due to the mild climate andexposure to oceanic currents which transport larvae.Examples <strong>of</strong> these in sandy substrates in <strong>Scilly</strong> arethe spiny cockle Acanthocardia aculeata, a hermit crabCestopagurus timidus and the trumpet anemone Aiptasiamutabilis (English Nature, 2000).Trends and IssuesResearch<strong>The</strong> SSSI at St Martin’s flats is monitored by NaturalEngland as part <strong>of</strong> their commitment to monitoringthe Special Area <strong>of</strong> Conservation features. This iscarried out at least once every six years. <strong>The</strong> methodinvolves monitoring the infauna <strong>of</strong> the sediment <strong>of</strong>three biotopes on the sand flats and analysis by Multi-Dimensional Scaling ordination to look at similaritiesand differences between biotopes and changes overtime (Warwick, 2004).Aggregate ExtractionIn the past, extraction <strong>of</strong> marine sands hadsignificantly affected the coastline at Bar Point onSt Mary’s and to a lesser extent at Crab’s Ledge onTresco. Since 1999 a Coastal Protection Order has beenin place to prevent large-scale sand and aggregateextraction from the seashore within the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>down to the 10-metre depth contour line (EnglishHeritage, 2004).Tourism / RecreationAt low tide large areas <strong>of</strong> sandflats are exposed andmay be used for recreation. <strong>The</strong>re has been no study <strong>of</strong>the effects <strong>of</strong> trampling on the sand flats here but it islikely to be negligible due to the large area over whichthe trampling is spread.PollutionOil pollution could be very damaging to this habitat.Other pollution is also a risk, particularly as pollutantscan become bound to sediments and persist inthe long term. Heavy metals and other toxins canaccumulate in sediment. In some limited areas theremay be persistent pollution due to past refuse disposalactivities at dumping grounds.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 66 Maritime Cliff and SlopesOverviewAlthough there are no very high cliffs in the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> there are cliffs and slopes all around thecoastline <strong>of</strong> the islands. As the definition also includesthe landward extent <strong>of</strong> the influence <strong>of</strong> deposition <strong>of</strong>salt spray (about 500m) many <strong>of</strong> the smaller islandsand large areas <strong>of</strong> the main islands are involved. Sothere is considerable overlap with inland habitats suchas lowland dry acid grassland and lowland heathlandand there is <strong>of</strong>ten no obvious demarcation. On theseaward side, the plan extends to the limit <strong>of</strong> thesupralittoral zone and so includes the splash zone andthe lichens and other species occupying this habitat.<strong>The</strong> vegetation <strong>of</strong> maritime cliff and slopes variesaccording to the amount <strong>of</strong> exposure to wind and saltspray and the geology <strong>of</strong> the underlying rocks. <strong>The</strong>most maritime vegetation types are found where thereis greatest exposure to the elements – in <strong>Scilly</strong> on themore western coasts. On exposed granite cliffs wherehigher vegetation cannot get a foothold such as on theWestern Rocks, virtually the only vegetation will bealgae and lichens. Where crevices can give a modicum<strong>of</strong> shelter, plants <strong>of</strong> the MC1 rock crevice communitysuch as rock samphire Crithmum maritimum and rocksea spurrey Spergularia rupicola can get a toehold.On the rocky carns and outcrops is a very typicalMC5 Armeria maritima – Cerastium diffusum maritimetherophyte community where several rare speciessuch as orange birds-foot Ornithopus pinnatus andciliate strap-lichen Heteroderma ciliata occur. Seabirdnesting ledges enriched by guano support particularcommunities including MC6 Atriplex prostrata - Betavulgaris maritima characterised by oraches Atriplexspp and sea beet with grasses and sea mayweedTripleurospermum maritimum.Maritime grasslands occur on cliffs and slopes inless severely exposed locations; a maritime form <strong>of</strong>red fescue Festuca rubra is a constant component <strong>of</strong>several more plant communities MC8 Festuca rubra– Armeria maritima, MC9 Festuca rubra-Holcus lanatus,MC10 Festuca rubra – Plantago spp. & MC12 Festucarubra- Hyacinthoides non-scripta, together with maritimespecies such as thrift Armeria maritima, sea plantainPlantago maritima, buck’s-horn plantain P. coronopusand sea carrot Daucus carota ssp gummifer. Species<strong>of</strong> inland grasslands that also commonly occur inmaritime grasslands include ribwort plantain Plantagolanceolata, bird’s-foot trefoil Lotus corniculatus, commonrestharrow Ononis repens and several species <strong>of</strong> grass.On cliffs and slopes more sheltered from the prevailingwinds and salt spray, the vegetation communitiesare more similar to those found inland. <strong>The</strong> uppersections and cliff-tops <strong>of</strong> hard cliffs on acidic rocksmay support maritime heaths characterised by heatherCalluna vulgaris.Maritime cliffs are <strong>of</strong>ten significant for theirpopulations <strong>of</strong> breeding seabirds, many <strong>of</strong> which are<strong>of</strong> international importance. Some areas <strong>of</strong> s<strong>of</strong>ter ramcliffs provide nesting sites for solitary bees. <strong>The</strong>reare also seepages and springs at the base <strong>of</strong> the cliffsthat provide additional habitat for invertebrates andcoastal plants including shore dock Rumex rupestris.<strong>The</strong> supralittoral zone represents the lowest belt <strong>of</strong>terrestrial vegetation on maritime cliffs and is usuallynotable for a zone <strong>of</strong> orange and grey maritimelichens. <strong>The</strong>se include Caloplaca marina, Ramalinasiliquosa and Verrucaria maura, also uncommon speciessuch as Roccella filiformis and R. phycopsis.Distribution and ExtentThis is one <strong>of</strong> the most extensive habitats in <strong>Scilly</strong>.Cliff communities are found on all the inhabited andthe larger uninhabited islands. Due to the constanteffects <strong>of</strong> salt spray and winds in many places the cliffvegetation merges seamlessly into the more inlandheathland and grassland communities.Conservation Importance<strong>The</strong>se maritime habitats are a feature <strong>of</strong> southwestBritain. Those around the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have linkswith those <strong>of</strong> <strong>Cornwall</strong>, especially the Lizard, but alsohave significant differences in geology and speciescomposition.Threats and IssuesMany <strong>of</strong> the cliffs in <strong>Scilly</strong> are subject to severe erosiondue to undercutting <strong>of</strong> the s<strong>of</strong>ter ram that underliesthe granite.Sea level rise and storm surges are also eroding thecliffs.Invasive alien plants such as Carprobrotus spp. may inplaces overwhelm cliff vegetation.Erosion <strong>of</strong> coastal paths has been a concern in places asthey are quite fragile, and it is sometimes not possibleto move them due to boundaries. Some have falleninto the sea.Thrift Armeria maritima flowering on cliffs influenced by sea spray.Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 67 PondsOverviewPonds are small bodies <strong>of</strong> open water up to abouttwo hectares in extent. Anything larger would beconsidered a lake. Some ponds are permanent waterbodies and others may be seasonal and dry up duringsummer.Distribution and Extent<strong>The</strong>re are small ponds on a number <strong>of</strong> the inhabitedislands, some <strong>of</strong> which may have been man-made towater livestock. Many <strong>of</strong> them are slightly saline attimes due to percolation through dune banks from thesea, directly through leats or from wind-blown saltspray. <strong>The</strong>re are also pools on the larger uninhabitedislands, some <strong>of</strong> which are seasonal.Conservation ImportanceMany <strong>of</strong> the ponds have a fluctuating flora withplants typical <strong>of</strong> the NVC Ranunculus baudotii(A21) community. <strong>The</strong>se pools may contain beakedtasselweed Ruppia maritima and fennel-leavedpondweed Potamogeton pectinatus as well as thebrackish water crowfoot Ranunculus baudotii. Some <strong>of</strong>these ponds have sluices to control water-levels anddrain rain water into the sea.Other pools have different floras. Coldwind Poolon St Martin’s for example is usually covered in afloating mat <strong>of</strong> bulbous rush Juncus bolbosus. <strong>The</strong>small pond on Bryher still has common spikerushEleocharis palustris and lesser marshwort Apiuminundatum present despite being planted with waterlilies (formerly it had brackish water crowfootRanunculus baudotii and intermediate water-starwortCallitriche hamulata present). <strong>The</strong> seasonal pools suchas the one on Northwethel may have a draw-downzone sometimes with plants such as red goosefootChenopodium rubrum and sea milkwort Glaux maritima.<strong>The</strong>se pools also have an invertebrate fauna, largelyunrecorded and may also be <strong>of</strong> ornithologicalimportance, especially for migratory birds.Trends and IssuesOn St Mary’s several ponds have suffered fromenrichment due to large numbers <strong>of</strong> residentwaterfowl, including exotic ducks that are fed by thepublic and breed freely.<strong>The</strong> invasion <strong>of</strong> the water fern Azolla filiculoidesinto several ponds led in the past to an extremeprogramme <strong>of</strong> herbicide use in an attempt to clear thefern. This also had a detrimental affect on the existingflora <strong>of</strong> the ponds. Although the Azolla appear toreduce or disappear spontaneously, it is still found onseveral water bodies on both Tresco and St Mary’s andis likely to return.<strong>The</strong> loss <strong>of</strong> brackish water crowfoot Ranunculusbaudotii from many <strong>of</strong> the ponds where it was formerlyfound suggests there have been changes in the waterquality or other adverse factors. <strong>The</strong> only extant sitefor the plant is now the St Martin’s cricket field poolwhere it is very vulnerable.Small Pool on Bryher was recently ‘planted’ withwater lilies and other plants which have been partiallyremoved by the IoSWT, but the trend <strong>of</strong> ‘improvingpools’ in this way should be discouraged.Pool on St Martin’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 68 ReedbedsOverviewReedbeds are wetlands dominated by stands <strong>of</strong> thecommon reed Phragmites australis, where the watertable is at or above ground level for most <strong>of</strong> the year.In <strong>Scilly</strong> they tend to incorporate areas <strong>of</strong> open waterand ditches, and small areas <strong>of</strong> wet grassland and<strong>of</strong>ten willow carr Salix cinerea. Some <strong>of</strong> the <strong>Scilly</strong>reedbeds, especially on St Mary’s, are mosaics with searush Juncus maritimus (var atlanticus). Marsh harrierCircus aeruginosus has nested in the reedbed on Tresco.All the reedbeds provide roosting and feeding sites formigratory bird species.Distribution and Extent<strong>The</strong> reedbeds in <strong>Scilly</strong> are all quite small althoughtheir nature conservation value is significant and mostare SSSIs. <strong>The</strong>re is a typical reedbed around the GreatPool on Tresco and reedbeds or mixed reed/sea rushbeds on Higher and Lower Moors on St Mary’s.Conservation ImportanceReedbeds are important nationally for several keyspecies dependent on the habitat. In <strong>Scilly</strong> very little isknown about the invertebrate fauna <strong>of</strong> the reed beds.Reedbeds in <strong>Scilly</strong> were formerly more extensiveand wetter before land clearance, modification to theditches and water abstraction.Trends and IssuesLack <strong>of</strong> or inappropriate management <strong>of</strong>existing reedbeds has led to drying and to scrubencroachment.Some areas <strong>of</strong> reeds have been lost over the pastcenturies. <strong>The</strong>y have been drained and built on orconverted to other habitats.Water is abstracted from the Moors on St Mary’s forthe public water supply. This has led to lowering <strong>of</strong>the water table and changes in vegetation. <strong>The</strong>re areWater-level Management Plans for Lower & HigherMoors.<strong>The</strong> Moors were formerly grazed; reeds and rusheswere also harvested. Current management includescutting reeds and rushes on rotation, clearingvegetation around the tussock sedge Carex paniculatatussocks and controlling willow carr.<strong>The</strong> significance <strong>of</strong> the endemic form <strong>of</strong> the sea rushJuncus maritimus (var atlanticus) needs recognition;some stands <strong>of</strong> the rush should be retained.Higher Moors on St Mary’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 69 Saline LagoonsOverviewSaline lagoons are water-bodies that have links withthe sea. <strong>The</strong>y retain part <strong>of</strong> the seawater at low tidesand can be brackish or saline, even super-saline. <strong>The</strong>irconnection to the sea may be by percolation through asea bank or through a natural or man-made channel.DistributionIn the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> there is now only one true salinelagoon although it is very likely other pools such asBig Pool on St Agnes, Great Pool on Tresco and PorthHellick pool on St Mary’s were formerly lagoons.Conservation ImportanceBryher Pool has a typical aquatic flora <strong>of</strong> beakedtasselweed Ruppia maritima, fennel-leaved pondweedPotamogeton pectinatus and with a narrow band <strong>of</strong>saltmarsh plants including saltmarsh rush Juncusgerardii, lesser sea-spurrey Spergularia marina andcommon saltmarsh-grass Puccinellia maritima aroundthe perimeter.<strong>The</strong> fauna has a fluctuating population <strong>of</strong> greymullet Chelon labrosus, shore crabs Carcinus maenas,common goby Pomatoschistus microps, prawnsPalaemontes varians and other crustaceans. BryherPool also has lugworms Arenicola sp. living in thesilty bottom.Bryher Pool is included in the Popplestone Bank andBryher Pool SSSITrends & Issues<strong>The</strong> lagoon is vulnerable to pollution, especially fromthe overflows or run-<strong>of</strong>f from the nearby hotel. <strong>The</strong>reis also a large rubbish pit not far away.<strong>The</strong> leat and sluice must be maintained in goodorder to protect the lagoon and the water quality/salinity.<strong>The</strong> pool should be protected from any futuredevelopment <strong>of</strong> the hotel that may have adverseeffects on the water quality.Bryher with the saline lagoon clearly visible. Photo: RNAS Culdrose SAR flight<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 70 Seagrass BedsOverviewSeagrasses are the only group <strong>of</strong> truly marineflowering plants. <strong>The</strong>y grow in beds or meadows ins<strong>of</strong>t sediment which is sheltered from strong waveaction. In the UK they maybe found from the uppershore, to a depth <strong>of</strong> about ten to fifteen metres, beyondwhich light penetration is a limiting factor.Seagrasses are present throughout the World’s tropicaland temperate seas but in the UK the only generapresent are Zostera (eelgrass) and Rupia (which occursin sheltered, muddy brackish waters). <strong>The</strong> two species<strong>of</strong> Zostera in this country are Zostera marina (normallyfully marine and subtidal) and Zostera noltii (dwarfeelgrass) which is more commonly found on the lowerto mid-shore.Eelgrass beds have an extensive network <strong>of</strong> leaves,roots and rhizomes and the structural complexity<strong>of</strong> the beds <strong>of</strong>fers a variety <strong>of</strong> ecological niches forother species. Zostera communities can be composed<strong>of</strong> numerous species <strong>of</strong> algae, hydroids, anemones,molluscs and fish. <strong>The</strong>y are particularly important asspawning and nursery areas for many fish species,some commercially important. <strong>The</strong>y play an importantrole in stabilising sediment, helping to retain it incertain areas (e.g. in the bay at Par Beach, St Martin’s)and allowing it to be colonised by other plants andanimals (Cook et al, 2001).An interesting feature <strong>of</strong> seagrass beds in <strong>Scilly</strong> isthe presence <strong>of</strong> ring shaped areas <strong>of</strong> eelgrass withbare sand in the centre. <strong>The</strong>se ‘doughnuts’ are fairlycommon here and may be a result <strong>of</strong> current actiondislodging the centre <strong>of</strong> the bed and a ‘blow out’forming (Fowler and Pilley, 1992). <strong>The</strong>y also appear inthe algal communities. Another possible explanation isthat they are a result <strong>of</strong> the underlying archaeology (R.Parslow, pers. comm.).Distribution and extentFollowing its loss from many areas <strong>of</strong> the country dueto a wasting disease in the 1930s, the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> hasbecome one <strong>of</strong> the most important areas nationally forZostera marina var. marina beds. However, even in <strong>Scilly</strong>,the once vast meadows <strong>of</strong> seagrass which extended overhundreds <strong>of</strong> acres <strong>of</strong> sandflats including intertidal areas,have largely been lost due to this disease. Recovery hasoccurred to some extent but seagrass is still very limitedin intertidal areas (Harvey, 1969).Much <strong>of</strong> the area between the islands is shallow andsheltered and provides suitable habitat for seagrass.Granitic sediments settle rapidly and leave the waterclear, providing good conditions for photosynthesisand encouraging the growth <strong>of</strong> seagrass beds. <strong>The</strong>majority <strong>of</strong> the seagrass beds are subtidal but atseveral sites (Hugh Town harbour, Porth Cressa,Gimble Porth, the Cove between St Agnes andGugh and Porth Conger) there are intertidal areas <strong>of</strong>seagrass.Some mapping has been carried out based onaerial photography during the 1980s and 90s. In1999 a student from Plymouth University mappedthe distribution <strong>of</strong> the Zostera beds using aerialphotographs and a GIS based technique andestimated the total area to be approximately 307ha(3.07Km2). Analysis <strong>of</strong> all available aerial survey databy Hocking and Tompsett, 2002 gave an estimate <strong>of</strong>total area <strong>of</strong> 348.25ha.Five main seagrass beds exist in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>and the Zostera Survey Team hopes to carry outgenetic analyses to determine whether these separatepopulations were once one large area <strong>of</strong> seagrass.Conservation Importance<strong>The</strong> seagrass beds <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are the mostextensive in the whole <strong>of</strong> the southwest and are <strong>of</strong>very high conservation importance due to their extentand the richness <strong>of</strong> their associated flora and fauna(Hocking and Tompsett, 2002). <strong>The</strong> seagrass bedsgrow in two Annex I (European Habitats Directive)habitats: ‘Sandbanks which are slightly covered byseawater all the time’ and ‘mudflats and sandflats notcovered by seawater at low tide’ and are one <strong>of</strong> thekey reasons that the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is a Special Area <strong>of</strong>Conservation (SAC).Seagrass beds are a national BAP habitat and havea national Habitat Action Plan and a South WestRegional <strong>Biodiversity</strong> Action Plan. Natural Englandcategorises the seagrass beds <strong>of</strong> <strong>Scilly</strong> as being <strong>of</strong>international importance. In <strong>Scilly</strong> the most diversefaunal communities <strong>of</strong> any sedimentary area are foundamong the roots and rhizomes <strong>of</strong> the Zostera beds, anarea <strong>of</strong> particular diversity is found in the seagrass atRushy Point, Tresco (Nichols and Harris, 1982).Both species <strong>of</strong> Zostera occurring in the UK areconsidered to be nationally scarce (occurring in 16-100ten km squares).<strong>The</strong> Zostera beds do not fall within any <strong>of</strong> the SSSIs in<strong>Scilly</strong>.Seagrass beds in <strong>Scilly</strong> support many speciesincluding large numbers <strong>of</strong> juvenile fish (A Hicks,pers. comm.). Within the Zostera communities thereare some rare southwest species <strong>of</strong> algae includingnationally rare Asparagopsis armata. <strong>The</strong>y also supportthe nationally rare hydroid Laomedea angulata andprobably two species <strong>of</strong> seahorse short-snoutedseahorse Hippocampus hippocampus and the spiny orlong-snouted seahorse Hippocampus guttulatus (bothseahorses are both BAP species and internationallythreatened).Short-snouted seahorses are thought to breed in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 71

eelgrass beds in <strong>Scilly</strong>. This species on the IUCN RedList <strong>of</strong> threatened species as ‘Vulnerable’, and is alsoan OSPAR priority species.Trends and IssuesEelgrass and eelgrass beds are classified as highlysensitive within the MarLIN (the Marine LifeInformation Network) Biology and Key InformationDatabase. <strong>The</strong>y are very highly sensitive to substratumloss, smothering, turbidity, wave exposure andnutrients and highly sensitive to displacement.Coastal development, dredging, run-<strong>of</strong>f, mooring andanchoring are all issues which have the potential tonegatively influence seagrass beds.ResearchMonitoring <strong>of</strong> the eelgrass beds was started byHiscock in 1984 and continued almost annually until1991 by the Nature Conservation Bureau on behalf<strong>of</strong> English Nature (Now Natural England). Between1992 and 2000 the seagrass beds were monitored byCoral Cay Conservation Sub Aqua Club volunteerswith annual reports produced for English Nature,documenting changes in the health and abundance <strong>of</strong>seagrass. Following this, monitoring was conducted bythe Zostera Survey Team, which continued to submitreports to English Nature.<strong>The</strong>re is a lack <strong>of</strong> good historical baseline data butoverall there currently seems to be a declining trend inseagrass abundance.In 1986 Hiscock studied the associated algae <strong>of</strong> theZostera beds.Natural cyclesZostera beds die back naturally in the winter months,re-growing again in spring. Furthermore seagrassesare naturally variable as a result <strong>of</strong> environmentalfluctuations such as sunlight intensity, freshwaterpulses, exposure to air and severe storms. <strong>The</strong>seenvironmental stressors can cause die-backs and thisnatural variability should be taken into considerationwhen assessing human impacts on seagrass. Variationsin populations <strong>of</strong> epiphyte grazers such as thegastropod Nucella lapillus can also influence the health<strong>of</strong> seagrass beds.water and potting does not occur in areas with seagrass.During spring tides in the summer season shrimping iscarried out by tourists and local artisanal fishers at lowwater on the sand flats. In some places this may occurin seagrass therefore there may be some tramplingimpacts. At present this is low key and restricted toabout 32 possible days per year, during the summermonths (AONB management plan, 2004).PollutionEelgrasses accumulate tributyl tin (TBT) and possiblyother heavy metals and organic pollutants which mayaffect the viability <strong>of</strong> the plant and may be introducedto the food chain.In <strong>Scilly</strong>, where untreated sewage is dischargedinto the marine environment there is a potential forthe elevated nutrient levels to impact the seagrass.Nutrient run-<strong>of</strong>f and suspended sediments fromagricultural fields could also affect the Zostera beds.DiseaseIn the 1930s a wasting disease killed much <strong>of</strong> theseagrass around the coast <strong>of</strong> Britain. Symptoms <strong>of</strong>this disease, which is caused by the slime mouldLabyrinthula were observed in <strong>Scilly</strong> during the 1980sand 90s (Fowler, 1992) and reductions in the extent <strong>of</strong>the seagrass beds may be attributable to the disease.<strong>The</strong> disease is still present in the population butmainly affects the outer leaves <strong>of</strong> the plants, not theinner, newly growing seagrass blades (K. Cook, pers.comm.).Invasive Species<strong>The</strong>re is a suggestion that the seagrass beds in the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> are being affected by the non-native brownalga Sargassum muticum. This was first recorded therein 1991 (Fowler, 1991) and has spread throughout theislands. It competes for space and sunlight with theeelgrass but now appears to be less aggressive in itsspread than first feared.Boating ImpactsPropeller wash from boats in shallow waters such asharbours where seagrass <strong>of</strong>ten grows can erode orsmother seagrass beds. An increase in the number<strong>of</strong> fast boats in <strong>Scilly</strong> recently could have an impact.Anchoring and mooring can also cause direct physicaldamage. Cook et al (2001) noted damage fromheavy chains tied to mooring blocks at Old GrimsbyHarbour, Tresco.Fisheries ImpactsSeagrass beds can be damaged by bottom fishing gearbut at present in <strong>Scilly</strong> trawling only occurs in deeperSeagrass Zostera marina forms meadows in the clear, shallow,sheltered waters near the islands. Photo: Tom Reid<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 72 Standing Open Water(Eutrophic Standing Waters andMesotrophic Lakes)OverviewStanding open water includes all the larger waterbodies in <strong>Scilly</strong> over two hectares in extent. Someare categorised as mesotrophic lakes, but they arenot typical and most are affected by occasional saltintrusion. <strong>The</strong> BAP habitats eutrophic standing watersand mesotrophic lakes are both included here as it hasnot yet been determined in which category most <strong>of</strong>these water bodies in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> belong.Distribution and ExtentSome, but not all <strong>of</strong> the larger water bodies in <strong>Scilly</strong>have associated reedbeds. Others may be surroundedby sea club-rush Bolboschoenus maritimus or sea rushJuncus maritimus.Conservation importanceVery little information is available about the flora <strong>of</strong>the lakes in <strong>Scilly</strong> and even less <strong>of</strong> their invertebrateand vertebrate fauna. Some <strong>of</strong> the plant speciesrecorded in earlier accounts are no longer presentand there appear to be considerable fluctuations inthe abundance and species <strong>of</strong> aquatic plants. Many<strong>of</strong> the lakes are <strong>of</strong> ornithological importance, both forbreeding birds and as a refuge for migrants. TrescoGreat Pool and Porth Hellick Pool, as well as the smallpool on Lower Moors on St Marys are, or are includedin SSSIs. Abbey Pool on Tresco is not an SSSI, althoughit has an unusual and interesting flora.Trends and Issues<strong>The</strong> two wetland ‘Moors’ on St Mary’s are locallyimportant as water abstraction sites and have beenconsiderably modified to fulfil the requirements <strong>of</strong>both the IoS Council and nature conservation. Sluicesand other structures keep salt water from the siteand also keep levels <strong>of</strong> freshwater high at abstractionpoints. Both sites are subject to agreed WaterManagement Plans.<strong>The</strong>re is a sluice on Tresco Great Pool which drainsinto the sea. But some saltwater intrusion may stilloccur at times.<strong>The</strong>re have been potential pollution incidents in theditches that feed the lakes; pollution is always a riskwith the rubbish tip, agricultural run-<strong>of</strong>f and otherpossible sources close by.<strong>The</strong> water fern Azolla has begun reinvading some<strong>of</strong> the lakes again and there is no easy or obviousdeterrent.Photo:<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 73 Tide-swept ChannelsOverview<strong>The</strong> tidal range in <strong>Scilly</strong> is about five metres duringspring tides. Strong tidal streams are unusual in<strong>Scilly</strong> and are rarely in excess <strong>of</strong> 3 knots. (Hiscock,1984). Tidal currents are most noticeable where watermovement is restricted between the islands. In thesechannels the flow rate can be up to 1.75m per second(Pingree and Maddock, 1985). In such tide-swept areasthe fine sands have been washed away, leaving onlycoarse sand, cobbles and pebbles (Cook et al, 1999).Tide-swept channels support characteristic, diversecommunities, exploiting the supply <strong>of</strong> particulate foodin the water. Filter feeders make use <strong>of</strong> the currentswhich deliver particles <strong>of</strong> food to their extendedfeeding apparatus. <strong>The</strong>se communities typicallyinclude s<strong>of</strong>t corals, hydroids (sea firs), bryozoans(sea mats), large sponges, anemones, mussels andbrittlestars. Tide-swept channels may supportcommunities <strong>of</strong> marine algae with long fronds suchas kelps and thongweed (UK <strong>Biodiversity</strong> Group).Tide-swept cobble habitats in <strong>Scilly</strong> have rich algalcommunities, considered to be <strong>of</strong> national importance(Barne et al, 1996)<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have been noted as providing agood example <strong>of</strong> tide-swept communities <strong>of</strong> nationalimportance (UK <strong>Biodiversity</strong> Group).Distribution and extent<strong>The</strong>re are channels between some <strong>of</strong> the islands whichcan be considered in this category. For example TeänSound between St Martins and Teän and St Mary’sSound between St Mary’s and Gugh. <strong>The</strong>se channelsare up to 20m or so deep and the effects <strong>of</strong> the tidescan be felt all the way to the bottom. <strong>The</strong>re is also atidal race between the Bishop Rock and the WesternRocks.Conservation ImportanceThis habitat is a newly renamed BAP habitat whichused to be called Tidal Rapids. <strong>The</strong> habitat has not yetbeen formally described therefore interpretation <strong>of</strong> thistitle is somewhat subjective.Constant movement <strong>of</strong> coarse sand and gravel intide-swept channels can make it a difficult habitat tocolonise but it may support burrowing anemones,worms and sea cucumbers.Trends and IssuesEnergyIn 2007 the Environment Minister Ben Bradshawmentioned that good energy resources were foundnear <strong>Scilly</strong> in his speech at the Wave and Tidalconference <strong>of</strong> the British Wind Energy Association,2007. In the future there is a possibility that theseresources will be exploited as a source <strong>of</strong> renewableenergy.ResearchHiscock (1984) categorised survey sites according toexposure to wave action and to tidal streams.Boating Impacts<strong>The</strong>re is some mooring <strong>of</strong> boats in tide-swept channels.For example Teän Sound has a number <strong>of</strong> fixedmooring points in the channel.Fisheries ImpactsDue to the strong currents in tide-swept channels,fisheries such as potting are not likely to occur.Filter feeders are abundant in areas with strong tidal currents. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 74 Wet WoodlandOverviewThis habitat is mostly found in the large fen habitats asareas <strong>of</strong> willow and alder carr. On <strong>Scilly</strong> the majority<strong>of</strong> it is a form <strong>of</strong> fen woodland.Distribution & Extent<strong>The</strong>re is very little woodland in <strong>Scilly</strong> and none thatcould be described as Ancient Woodland. Somewet woodland exists as part <strong>of</strong> a larger complex, forexample willow carr in Higher and Lower Moors.Other woodland has arisen partly by invasion <strong>of</strong> elmUlmus hollandica into willow woodland as in the HolyVale Nature Reserve.Conservation ImportanceMost <strong>of</strong> the wet woodland in <strong>Scilly</strong> conforms to W1Salix cinerea – Galium palustre woodland although itis missing some elements such as other tree species.Very little is known about the invertebrate fauna <strong>of</strong>these areas, they are known to be attractive to birds,especially migrants and the large amounts <strong>of</strong> deadwood suggest there may be invertebrate interest. Fernsand bryophytes appear to be well represented.Trends & Issues<strong>The</strong>re may have been more wet woodland in formeryears.Other than some clearance to prevent willowencroachment into other habitats on the Moors verylittle management work is undertaken.Increased water abstraction could have a detrimentalaffect.<strong>The</strong> stream at Higher Moors on St Mary’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 75

3Issues affecting <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>biodiversity<strong>The</strong> following issues have been identified as having some influence on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s biodiversity.3.1 Nature Conservation3.2 Agriculture3.3 Fisheries3.4 Built Development3.5 Transport and Access3.6 Air and Terrestrial Pollution3.7 Marine Pollution3.8 Water Resources3.9 Climate Change3.10 Tourism3.11 Economic DevelopmentEach issue is discussed in relation to:· An overview <strong>of</strong> historic and current trends influencing biodiversity· Major policies, schemes and organisations involved· Relevant sub-issues with respect to the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>This section provides an overview to the influences and pressures on biodiversity and should provide a baselinewith which to inform debate during production <strong>of</strong> any action plans or further work.Lowertown Quay on St Martin’s. Photo: Angela Gall<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 76

3.1 Nature ConservationOverviewPublic appreciation <strong>of</strong> wildlife conservation hasdramatically increased over the last 50 years; this islargely a result <strong>of</strong> a growing interest in wildlife andan elevated level <strong>of</strong> public awareness at the rate whichbiodiversity is changing. It is generally perceived tobe in overall decline. <strong>The</strong> growth in both statutory andvoluntary organisations has occurred simultaneouslyover the same period.<strong>The</strong>re are currently a wide range <strong>of</strong> natureconservation organisations, incentive schemes,laws, site designations and policies that impact onthe biodiversity <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. A significantproportion <strong>of</strong> the islands’ land and marine holdingsis subject to some form <strong>of</strong> conservation designationor protection. <strong>The</strong>re are a number <strong>of</strong> organisationsand individuals playing important roles in conservingand enhancing the biodiversity <strong>of</strong> the islands andsurrounding waters.Major Policies, Schemes and Organisations<strong>The</strong> major players directly involved in natureconservation on the islands are Natural England,<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong>, Royal Society for theProtection <strong>of</strong> Birds, <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Council, the Duchy<strong>of</strong> <strong>Cornwall</strong>, <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Bird Group and the TrescoEstate. A large proportion <strong>of</strong> the land and marine areasare subject to statutory or non- statutory designations,whilst Tresco is privately owned, but has SSSIs andsome biodiversity planning actions within its landmanagement plans.<strong>The</strong> approximate coverage on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>of</strong>different site designations and/or reserves is asreported below.overview <strong>of</strong> the funding opportunities open to them.IssuesCooperation<strong>The</strong>re is always potential for conflict <strong>of</strong> interestsbetween organisations or the possibility <strong>of</strong> theduplication <strong>of</strong> conservation effort. In particular the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong> was under resourced andwas responsible for managing 60% <strong>of</strong> the terrestrialland cover <strong>of</strong> the islands (excluding Tresco). Thisis being partially alleviated by a closer cooperationbetween the <strong>Trust</strong> and their close neighbours in<strong>Cornwall</strong>.Site DesignationsLarge swathes <strong>of</strong> the terrestrial land and all <strong>of</strong> themarine habitats up to the 50 metre depth contourare subject to one or more statutory or non-statutorydesignations. <strong>The</strong>se require significant managementwith limited resources.Of the 26 SSSIs, most are reported to be in asatisfactory condition. <strong>The</strong>re is little reported loss ordegradation <strong>of</strong> semi-natural habitat, although thereremains a paucity <strong>of</strong> key information for the marineenvironment against which to measure change. It isthe aim that this audit and any subsequent follow onwork will go some way to rectifying this.AwarenessHistorically, there has been a lack <strong>of</strong> awareness <strong>of</strong> theimportance <strong>of</strong> key conservation sites and habitat. Thishas been addressed and biodiversity and conservationare at the forefront <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Local Planadopted in 2005.Site DesignationArea (Hectares)Conservation AreaAll <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Heritage CoastAll coastlineArea <strong>of</strong> Outstanding All <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Natural Beauty (AONB )Ramsar Site401.64haSpecial Protection Area 401.64 haEU Habitats Directive (SPA)Special Area <strong>of</strong> Conservation 26,851 ha (<strong>of</strong> whichEU Habitats Directive (SAC) 181.32 ha is terrestrial)Non Statutory Marine Park All marine to the 50metre contourSSSIs – 26 sites (5 geological) 554,98 haFunding for biodiversity projects is available from anincreasingly diverse range <strong>of</strong> sources with both grantsand incentive schemes being actively promoted e.g.Higher Level Stewardship for significant amounts<strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong> holdings. It isimportant that all organisations involved maintain an<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 77

<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 78Map <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> showing selected site designations

3.2 AgricultureOverviewAlthough tourism is undoubtedly the mainstay <strong>of</strong>economy <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, the favourable climateis conducive to early flower production and largesections <strong>of</strong> land are put over to bulb and early flowerproduction. Additionally, there has been a movetowards growing vegetables and alternative flowers.While there has been an increase in livestock forslaughter, the absence <strong>of</strong> a dedicated abattoir for theislands remains a limiting factor in wider expansion <strong>of</strong>livestock for meat farming. <strong>The</strong> impact <strong>of</strong> agriculturalpractices on the islands will have an effect on theisland’s biodiversity and changes in practices willneed to be monitored to assess the overall impact.Major Policies, Schemes and OrganisationsIn the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, the farming community ispredominantly tenant farmers renting land fromthe Duchy <strong>of</strong> <strong>Cornwall</strong> or the Tresco Estate on thatprivately owned island. <strong>The</strong>re have been some recentdevelopments with tenant farmers having a greateropportunity to diversify their outputs, particularly intourism activity, as there was little scope to increaseoutput from their primary agricultural businesswithout significantly impacting on the speciallandscape character <strong>of</strong> the islands. Flower growing hasbecome considerably less pr<strong>of</strong>itable in recent years,mainly due to large importations <strong>of</strong> flowers into theUK.IssuesViable Agricultural Population<strong>The</strong> number <strong>of</strong> people now trying to earn a livingfrom the land is shrinking. Viability depends on costreduction and towards this end there is some scope forfarm amalgamations but this will lead to fewer peopleemployed in the industry. Increasingly marginalland will be let out <strong>of</strong> production and used for otheractivities, leaving only best and most sheltered landused for narcissus.Bulb fields on St Mary’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 79

Flower and Bulb Growing<strong>Scilly</strong> is renowned for the quality and technicalcompetence <strong>of</strong> flower and bulb production. Combinedwith the favourable climate, this allows a start to theflower season very early (in September) and maintainsa six month period <strong>of</strong> production. Producers are ableto get produce on the market significantly earlier thanmost mainland competitors, provide continuity <strong>of</strong>supply over a longer period and to specialise in theTazetta narcissus. Despite this there are still high labourcosts and the emphasis must be on the production <strong>of</strong>high quality specialist products. Equally, producersmust develop and maintain close liaison with the keymarket leaders in order to maximise their marketingskills.Highly developed technical skills in bulb and flowerproduction and specialist bulb equipment are the keysto the success <strong>of</strong> smallholders and tenant farmers inthis sector and these skills need to be enhanced toensure <strong>Scilly</strong> remains at the forefront <strong>of</strong> the industry.<strong>The</strong> presence <strong>of</strong> the Research and Development Stationat Trenoweth is important in enabling local producersto enhance their skillsAlternative CropsSome smallholders may move to alternative crops,but it is unlikely these crops will completely displaceflowers and bulbs. Livestock farming for meat foranything other than limited “traditional” slaughteringremains uneconomic unless the islands have adedicated abattoir; there remains ongoing debate as tothe viability <strong>of</strong> this.<strong>The</strong>re are now no bulb farmers on Bryher, only twoon St Agnes, probably only one or two St Martin’s.Several now specialise in scent production; manyfarmers are already moving to alternative crops anddiversifying where possible.Agri-Environmental Schemes<strong>The</strong> use <strong>of</strong> agri-environmental funding can beinflexible and targeted at crops not viable on <strong>Scilly</strong>and their use is very limited on the islands. <strong>The</strong> lack<strong>of</strong> many <strong>of</strong> these schemes on the islands will havean impact on biodiversity. <strong>The</strong>re is further workunderway to identify ways <strong>of</strong> incorporating SingleFarm Payments into the agricultural uniqueness <strong>of</strong> theislands as there would be significant environmentalbenefits to be gained.the Tresco Estate, particularly in the arable margin andhedge habitats.Diversification<strong>The</strong> requirement for smallholders and tenantsto maintain a level <strong>of</strong> sustainability may lead tothe requirement to diversify outputs outside <strong>of</strong>agriculture. <strong>The</strong> obvious outlet for this would betourism and there is already some move to developnew tourist accommodation to supplement farmincome. This is addressed in the Local Plan.Specific Project for Agriculture on <strong>Scilly</strong>Farmers have formed a cooperative called the “Group<strong>of</strong> 43” and they successfully obtained ObjectiveOne funding for this project. It particularly looksat marketing initiatives (Scent from the Islands andScented Narcissus) as well as reviewing diversificationand the re-establishment <strong>of</strong> a dedicated abattoir.Local ProduceIn line with a national trend towards buying morelocal produce the AoNB organised a monthly farmers’market throughout the summer. This is part <strong>of</strong> a movetowards more use <strong>of</strong> locally produced food within the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. A local food directory has been set up andmany local restaurants and hotels are moving towardsgreater use <strong>of</strong> local seafood and farm produce.Abattoir<strong>The</strong>re is currently no abattoir on <strong>Scilly</strong>, which limitsthe production <strong>of</strong> meat on the islands. Plans have beenput forward for an abattoir on St Marys and the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong> is supportive <strong>of</strong> this, althoughthe economic viability <strong>of</strong> such a project remainsan issue. <strong>The</strong>re is potential for the project scopeto be widened into a holistic facility for handling,processing, branding and marketing a range <strong>of</strong> localproduce. This would have the added advantage <strong>of</strong>promoting agricultural diversification and may attractadditional funding. Furthermore, the widening <strong>of</strong> therotation on the farmed land by growing foraged crops(for cattle feed) would enhance soil fertility and benefitthe narcissus crop by lessening the impact <strong>of</strong> pests anddiseases.Natural England has submitted a Special Project statusfor the islands; this is currently under consideration.This status will allow some bids for both Entry andHigher level Stewardship to receive favourableconsideration in view <strong>of</strong> the unique environmentalheritage <strong>of</strong> the islands. Higher Level Stewardship(HLS) is being pursued by some tenant farmers and by<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 80

3.3 FisheriesOverviewFor many years fishing was one <strong>of</strong> the major economicactivities in <strong>Scilly</strong> but the industry has dwindledand fishing now accounts for about 5 percent <strong>of</strong> theislands’ GDP (roughly the same as the flower farmingindustry). Most fishing is low key, seasonal lobsterpotting or netting although there are currently twotrawlers which are active all year round. Shorebasedand boatbased recreational angling is a popularsport in <strong>Scilly</strong> and is important for tourism. Withinthe territorial waters <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> fishing iswell regulated by national laws and a series <strong>of</strong> localbylaws. Migratory or wide-ranging fish species aswell as cetaceans and turtles which may be caught asbycatch can be affected by fishing activities outside theterritorial waters, beyond the jurisdiction <strong>of</strong> the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> Sea Fisheries Committee.Major policies, schemes and organisationsLocally, fisheries are managed by the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> SeaFisheries Committee (SFC) <strong>of</strong> the Council. <strong>The</strong> SFC hasthe power to pass bylaws to regulate fisheries in theirterritorial waters (from low water out to 12 nauticalmiles). Enforcement is carried out by the SFC’smaritime <strong>of</strong>ficer and Honorary Patrol Officer (a localfisherman who has been appointed to the post, givinghim the legal power to enforce fisheries legislation).Other local fishermen also help to enforce legislationby reporting any suspicious activity by radio duringthe course <strong>of</strong> their work. Through a cross-warrantingagreement <strong>Cornwall</strong> SFC also have the power toenforce fisheries legislation in Scillonian waters. Ifthe new marine bill is passed then the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>SFC may be lost as the bill aims to centralise fisheriesmanagement. It is likely that the responsibilities <strong>of</strong>the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> SFC would then be taken over by<strong>Cornwall</strong> County Council.<strong>The</strong>re are currently about 30 registered fishing boatsin <strong>Scilly</strong> (this changes slightly each year but is roughlystable). Two are trawlers targeting flatfish, sole, JohnDory, sea monkfish and other demersal species; congereels and dogfish are taken as bycatch. <strong>The</strong> other boatsare mainly used for shellfish potting and small-scalenetting. Potting targets mainly edible crab, spider crab,velvet crab, lobsters and crawfish. Most <strong>of</strong> the nettingis for mullet, monkfish and turbot (M. Pender, pers.comm.). Between April and November fishing boatsfrom the mainland may fish in the waters <strong>of</strong>f <strong>Scilly</strong>over neap tides, returning to the mainland to landtheir catch before the spring tides.Some <strong>of</strong> the fish and shellfish are sold to localrestaurants and hotels and the rest is sold at Newlynfish market in Hayle (both on the mainland). <strong>The</strong>shellfish are sent by ferry to Penzance from where theyare collected by agents who deliver them to market.This short road trip leads means that the products arelabelled as ‘overland’, decreasing their market value.<strong>The</strong> trawlers operate all year round but the other boatsgenerally only work between May and October<strong>The</strong>re is a Fishermen’s Association which actsvoluntarily to improve sustainability and to providea voice for local fishermen in relation to policy andregulations. <strong>The</strong>y have introduced a v-notchingscheme for female lobsters; the tails <strong>of</strong> berried femalesare notched as the fishermen catch and release them,which means that it will be illegal (under a bylawapplying to the <strong>Cornwall</strong> Sea Fisheries District) to landthese animals until they have grown a new carapace- giving them potential protection for several years.Angling is a popular sport in <strong>Scilly</strong>, particularlywith summer visitors and several boats are availableto take sport fishermen out to <strong>of</strong>fshore reefs. Shorebased anglers mainly target wrasse, mackerel, pollack,mullet and flatfish. Boat fishing targets similar specieswith the addition <strong>of</strong> ling, cod and whiting as well assharks and rays. Sharks caught during these trips aretagged and released as part <strong>of</strong> a programme run bySouthampton University.During summer months artisanal shrimping by localsand visitors occurs at low water spring tides on thesandflats. This is possible on about 32 days each year(AONB Management Plan, 2004). Under a voluntarycode <strong>of</strong> conduct, shrimping is authorised between1st July and 30th September each year. Duringstakeholder consultation for the Area <strong>of</strong> OutstandingNatural Beauty management plan, concern wasexpressed that the current level <strong>of</strong> shrimping activitymay be too high.<strong>The</strong> National Lobster Hatchery at Padstow has workedwith members <strong>of</strong> the Sea Fisheries Committee andlocal divers to release 500 juvenile lobsters in 2002 and120 in 2007. <strong>The</strong>se were released by hand in suitablehabitats and will take many years to grow largeenough to enter the fishery.IssuesLegislation / policy<strong>The</strong> fisheries <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> are subject to all thenational legislation regarding fishing gear, minimumspecies size limits, boat and engine size restrictions,closed seasons and quotas.Outside the 12 nautical mile limit <strong>of</strong> the territorialwaters the Common Fisheries Policy applies whichmeans that boats from other EU countries can fishwithin the 200 nautical mile Exclusive Economic Zone.Within the territorial waters (up to the 6nm limit) theSea Fisheries Committee has the jurisdiction to createbylaws under the Sea Fisheries Regulation Act 1966which are ratified by DEFRA in a process which takesup to 2 years. <strong>The</strong>re are currently three bylaws:<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 81

1. Prohibits the use <strong>of</strong> vessels greater than 10 tonnesgross tonnage or 11 metres overall length forfishing within the Sea Fisheries District out to 6nautical miles.2. Prohibits the use <strong>of</strong> scallopers with more than4 dredges within the Sea Fisheries District out to4 nautical miles.3. Prohibits removal <strong>of</strong> lobsters with a carapacelength <strong>of</strong> less than 90mm from the fishery.Local initiativesIt has been suggested that a local branding initiativeis set up for seafood products to encourage localbusinesses to buy local products. <strong>The</strong> Area <strong>of</strong>Outstanding Natural Beauty already organise a localproduce market once a month and this includes locallycaught fish and shellfish when available.Species depletionSome fish populations have been shown to havedeclined due to fishing. In the southwest for examplethe spawning stock biomass <strong>of</strong> mackerel has fallensince the mid-1980s (Jones et al, n.d.). Managementmeasures can be brought in to tackle these declines butstocks <strong>of</strong> some species have continued to fall.Bycatch / non target speciesOne <strong>of</strong> the problems associated with most types <strong>of</strong>fishing gear is bycatch <strong>of</strong> non-target species whichmay include other commercial or non-commercial fishand seabirds such as shags and marine mammals.In the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> bycatch is not monitored andthe amount <strong>of</strong> discards produced by the fishing <strong>of</strong>non-target species is currently unknown. Pottingis more discriminate and produces fewer discardsthan trawling. Small scale netting produces verylow discards as the fish is not sold at market and istherefore not subject to quotas.Strandings <strong>of</strong> cetaceans are monitored by the <strong>Cornwall</strong><strong>Wildlife</strong> <strong>Trust</strong> Strandings Network and it is sometimespossible to determine whether the death is dueto fishing impacts; however it remains difficult toquantify these impacts or to attribute them to specificboats.its removal <strong>of</strong> species from the sea floor and has thepotential to damage or destroy seafloor communitiesvery rapidly. This is a particular problem for speciessuch as pink sea fans which are fragile yet very slowgrowing.Scallop dredging creates tracks and ridges on theseabed which can be visible for a long time in areas <strong>of</strong>low currents. It leads to suspension <strong>of</strong> fine sedimentsand large rocks may be overturned. In areas with littlewater movement near the bottom these impacts onthe micro-topography <strong>of</strong> an area can accumulate andpersist for months.Migratory speciesWhile fishing effort can be controlled fairly easilywithin the territorial waters <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, thepotential for overfishing <strong>of</strong> migratory species outsidethese waters is high. An example <strong>of</strong> this is the fact thatlobsters (a site attached species) have a fairly stablepopulation in <strong>Scilly</strong> whereas crawfish are migratoryand their numbers are in decline, probably due tooverfishing by boats from other EU nations.Shark species are not targeted in <strong>Scilly</strong> but are globallythreatened by the shark fin trade. For highly migratoryspecies such as blue sharks the local population couldbe threatened by global issues.Fishing debrisDamaged or lost fishing gear can cause problemsin the marine environment. It is usually made fromdurable materials and can persist for many years.Fishing activity is one <strong>of</strong> four main sources <strong>of</strong>marine litter on UK beaches (Beachwatch, MarineConservation Society, 1999) with fishing debrisaccounting for 11.2% <strong>of</strong> the total litter found.Lost gear, such as lobster pots which have lost theirmarker buoys, has the potential to continue to catchfish and other species which will never be harvested(known as ghost fishing). Nets and other lost gear canentangle marine life such as cetaceans, seals, turtlesand seabirds. Nets can become snagged on branchingbenthic species such as seafans, affecting their growth.<strong>The</strong>re is also a potential risk to divers, who couldbecome entangled in fishing gear.Anecdotal evidence suggests that seals sometimes getentangled in fishing nets and lines in <strong>Scilly</strong> and thiscan be harmful to their health and can even kill them.Habitat destructionDredging is well known to be damaging to seabedcommunities, in particular to fragile sessile speciessuch as sea pens, sponges and corals. Howeverscallopers will normally avoid the rocky areaspreferred by many <strong>of</strong> these species due to the risk <strong>of</strong>damaging their gear. Dredging is indiscriminate in<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 82

3.4 Built DevelopmentOverviewAs with many island communities, there is adistinctive feel to the built development pattern. <strong>The</strong>‘capital’ <strong>of</strong> the islands is Hugh Town, on St Mary’s,built on a sand bar joining the main island withthe Garrison. <strong>The</strong> next largest development is OldTown, the original main settlement. Both Hugh Townand Old Town were subject to a 2003 survey by theEnvironment Service <strong>of</strong> <strong>Cornwall</strong> County Councilto assist in providing a framework for sustainableregeneration in the area.<strong>The</strong>re are a number <strong>of</strong> smaller developments on StMary’s, with residential accommodation at Telegraphand Porthloo, but, apart from these areas mostdevelopments are isolated farmsteads.On the <strong>of</strong>f islands, small clusters <strong>of</strong> buildings show apattern <strong>of</strong> development in areas most sheltered fromthe predominant winds and where the most fertileland exists. Little new building has taken place onthese islands. <strong>The</strong> exception to this is Tresco which,as a privately owned island, has been subject to newdevelopment in New Grimsby since 2000.Any significant increase in built development on theislands may well have an impact on biodiversity;it will be dependent on what land is used for thatdevelopment and habitat mapping will identifypockets <strong>of</strong> habitat type where such development mayhave the most detrimental effects.supports proposals that would contribute to thefurther diversification and essential modernisation<strong>of</strong> the islands economy, whilst protecting the localenvironment. Specifically, the Local Plan has identifiedland at McFarland’s Down, Telegraph and Normandyon St Mary’s for new housing to meet the needs <strong>of</strong>the community. This is designed to help providehomes for all islanders that require one without theneed for large new development. This is an importantconsideration as second home ownership on theislands is at one <strong>of</strong> the highest concentrations in theUK. Funding has also been secured to build a newschool base on St Mary’s.Use <strong>of</strong> Existing BuildingsIn appropriate circumstances, the Local Plan permitsdevelopment where a proposal would contributeto the sustainability <strong>of</strong> the islands’ environment,economy or local communities. <strong>The</strong> Local Plan alsosupports the re-use <strong>of</strong> existing buildings for theeconomic benefit <strong>of</strong> the islands providing any proposalis <strong>of</strong> a sympathetic design.A Design Guide has been prepared to supplementthe Local Plan to ensure that new proposals aresympathetic to the character <strong>of</strong> the islands andincorporate the principles <strong>of</strong> sustainability.ManagementLandscaping which is sympathetic to, and integratedwith, the surrounding countryside can minimise thevisual impact <strong>of</strong> any development and act as a bufferbetween it and wildlife habitats.Major Policies, Schemes and OrganisationsIn view <strong>of</strong> the exceptional quality <strong>of</strong> the environmentand the infrastructural constraints facing the islands,the over-arching aim <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Local Plan isto keep development to the minimum for sustainingthe islands’ communities. <strong>The</strong> Local Plan has beensubject to extensive consultation with the communityand key stakeholders, including the Duchy <strong>of</strong><strong>Cornwall</strong> and the <strong>Wildlife</strong> <strong>Trust</strong>.Copies <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Local Plan are availablefrom the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Council website.Additionally, in press for publication in Summer<strong>2008</strong>, is CWT’s <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Bio/GeodiversitySupplementary Planning document. This is anaddendum to the wider <strong>Cornwall</strong> Planning Guidancedocument published in 2007.IssuesDevelopment Pressure<strong>The</strong> policies and proposals in the Local Plan aregenerally restrictive. However, it does containpolicies that allow for a limited amount <strong>of</strong> affordablehousing to meet the needs <strong>of</strong> the community and<strong>The</strong> harbour at Hugh Town, St Mary’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 83

3.5 Transport and AccessOverview<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> suffer, as do all island communities,from transport and access issues. <strong>Scilly</strong> is wellserved with good connections by air and sea fromthe mainland for both freight and passengers; theseare better in the summer months than the winter.<strong>The</strong> good links are maintained by the high touristattraction <strong>of</strong> the islands – this is discussed in Section3.10 <strong>of</strong> this report. Improved transport links, whilstgood for the economic development <strong>of</strong> the islands, willpotentially increase tourism and casual visitors whichcould impact on the biodiversity <strong>of</strong> the islands.Despite these good transport links, the cost <strong>of</strong> bothpassenger and freight services to the islands is higheven compared to other UK islands and inter islandtransport outside the tourist season can be erratic.Major Policies, Schemes and Organisations<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Steamship Company operates thepassenger ferry Scillonian III, the freight vessel GryMaritha and Skybus flights from Exeter, Newquay andLand’s End airports. This is augmented by an all yearround frequent helicopter service from Penzance runby British International Helicopters.To enable these transport links to work requiresclose cooperation between IoS Council, <strong>Cornwall</strong>County Council, Duchy <strong>of</strong> <strong>Cornwall</strong>, Penwith DistrictCouncil and the travel operators. <strong>The</strong>se stakeholdershave joined to create the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> TransportStrategy and Route Partnership to seek solutions forthe development, improvement and accessibility<strong>of</strong> transport links to the islands. As part <strong>of</strong> thepartnership funding was secured to improve St Mary’sQuay. In addition, funding has been secured to assistin the refurbishment <strong>of</strong> the <strong>of</strong>f island quays. All <strong>of</strong>these projects are identified in the Local Plan.IssuesInfrastructure ProjectsMajor projects such as refurbishment <strong>of</strong> the <strong>of</strong>f islandquays and St Mary’s quay require an EnvironmentalImpact Assessment to be carried out taking intoaccount the affect they may have on both the naturaland historic environment. <strong>The</strong>re will need to be a level<strong>of</strong> compromise between the environmental issuessurrounding such capital works and the requirementto improve lifeline transport links to support the islandeconomy and community.Traffic LevelsTraffic levels are becoming an issue on St Mary’s giventhe paucity <strong>of</strong> roads to cope with any increase. Trafficlevels on the <strong>of</strong>f-islands are very low and are thereforenot an issue.Management<strong>The</strong> management <strong>of</strong> boundary features on roadsidesis a key biodiversity issue. <strong>The</strong>re needs to be lessmanagement to increase their biodiversity potential;these areas can become important semi-natural habitatwhich attracts a wide diversity <strong>of</strong> plants and animals.Scillonian III in St Mary’s harbour. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 84

3.6 Air & Terrestrial PollutionOverviewPollution can be defined as:<strong>The</strong> introduction by man into the environment<strong>of</strong> substances or energy liable to cause hazardsto human health, harm to living resources andecological systems, damage to structure or amenity, orinterference with legitimate uses <strong>of</strong> the environment(Holdgate 1979).It can take the form <strong>of</strong> “point source” pollution e.g.discharge into a watercourse, or “diffuse” pollutionsuch as agricultural run-<strong>of</strong>f. Its impact on biodiversitycan equally be limited in the time or area affected, orcan be spread over a longer period or wider area.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> probably suffer little from mostpollution issues; their inshore waters are amongst thecleanest in the UK, they have little traffic pollutionand the prevailing winds combined with little majorindustry on the islands ensures that overall airpollution is minimal.<strong>The</strong> most likely and significant threat to the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> is that <strong>of</strong> marine pollution, both from a majoraccident at sea or just an accumulation <strong>of</strong> marine wasteand this is addressed at 3.7.Waste disposal is a major issue for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>and has been addressed in the Local Plan.Major Policies, Schemes and Organisations<strong>The</strong>re has been a proliferation <strong>of</strong> environmental,waste and pollution legislation and all <strong>of</strong> these willbe implemented by the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Council. As aunitary council it has wider powers than other bodieslooking after a similar area. Additionally, the Councilreplaces the responsibilities <strong>of</strong> the EnvironmentAgency on the islands.IssuesWaste DisposalAs with all isolated communities, where to dispose<strong>of</strong> waste is a sensitive issue. Increased landfill willcompromise the integrity <strong>of</strong> the landscape and riskwater pollution. Re-cycling has been adopted andthe levels achieved have improved over recent yearswith glass and metal leading the way. Additionally, asmuch waste as is practical is burned in the incineratoron St Mary’s. Despite this encouraging position,there still needs to be an overall reduction in wasteproduced per head <strong>of</strong> population.Education/AwarenessContinuing education and awareness <strong>of</strong> waste andrecycling is being carried out under the auspices <strong>of</strong> the<strong>Scilly</strong> Waste project.Tresco. Photo: RNAS Culdrose SAR flight<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 85

3.7 Marine PollutionOverviewAbout 80 percent <strong>of</strong> marine pollution is derivedfrom land-based activities, <strong>of</strong>ten entering the marineenvironment through land run-<strong>of</strong>f or direct discharges(DEFRA, 2002). Contaminants become dispersed in themarine environment and are in highest concentrationsclose to the land. <strong>The</strong> influence <strong>of</strong> pollution frommainland sources depends on the nature <strong>of</strong> thecontaminant, many pollutants will not reach <strong>Scilly</strong>in significant concentrations whereas others such asplastics can travel thousands <strong>of</strong> kilometres. <strong>The</strong>re arealso sources <strong>of</strong> pollution from the islands, from vesselsat sea and atmospheric deposition.Chemicals may alter their properties once in themarine environment depending on their physiochemicalproperties and the marine conditionsthey are in. <strong>The</strong>y may also combine with otherchemicals (known as a ‘cocktail effect’) with unknownconsequences. Due to the distance from industrialareas and major sources <strong>of</strong> land based pollution<strong>Scilly</strong> is likely to have low levels <strong>of</strong> marine pollution;however this has been little studied or monitored.<strong>Scilly</strong> is at risk from oil spills or other pollution eventsassociated with shipping accidents. Toxins and soilmay enter the marine environment in run-<strong>of</strong>f waterfrom the land, particularly where farming is practisedvery close to the shore.Major policies, schemes and organisations<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong> is responsible for most<strong>of</strong> the Islands’ beaches. <strong>The</strong> Council for the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> clean certain beaches for tourism, such as PorthCressa on St Mary’s where cleaning also removes deadalgae from the strandline. On Tresco the beaches aremanaged by the Dorrien-Smith estate.Beachwatch and Adopt-a-Beach are schemes run bythe Marine Conservation Society, involving volunteersin beach cleanups and litter surveys. SeveralBeachwatch events have been held in <strong>Scilly</strong>, at PorthCressa beach (St Mary’s) and Middletown beach (StMartin’s). <strong>The</strong> Marine Conservation Society hopes tocontinue these events, involving the local communityand visitors, working with the Area <strong>of</strong> OutstandingNatural Beauty.During stakeholder consultation meetings for the Area<strong>of</strong> Outstanding Natural Beauty management plan,concern was expressed about the levels <strong>of</strong> litter andoil pollution and about the lack <strong>of</strong> funding for tacklingpollution incidents. Some stakeholders felt that theresponsibilities for responding to acute and chronicpollution problems was unclear (AONB ManagementPlan, 2004).Issues<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have a history <strong>of</strong> shipwrecks, dueto their many submerged reefs, rocks and banks andthe potential for stormy weather. <strong>The</strong> threat <strong>of</strong> futureshipping accidents is ever present. One <strong>of</strong> the first andlargest oil spills <strong>of</strong> modern times to affect the Englishcoast occurred on the Seven Stones Reef, 8 kilometreseast <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong> Torrey Canyon oil tanker hit the reefin 1967, spilling 100,000 tonnes <strong>of</strong> crude oil. Only thedirection <strong>of</strong> the prevailing wind at the time preventedthis from becoming a major disaster for <strong>Scilly</strong>, the oilcame ashore on the coast <strong>of</strong> the mainland and wasdamaging to the marine life there.In March 1997 the MV Cita, a 3038 GRT containerfeeder vessel foundered on Newfoundland Rocks atPorth Hellick on St Mary’s, spilling 145 containers.Localised fuel spillage occurred and the contents<strong>of</strong> the containers were washed up on many <strong>of</strong> thebeaches. <strong>The</strong> shipping company’s insurers took noresponsibility for this and the result was that thecouncil had to pay for the clean-up operation. Rolls<strong>of</strong> polythene film, a total <strong>of</strong> 3740 miles in lengthand 3 feet wide disintegrated and were distributedin the marine environment. Despite huge effortsby volunteers, less than 1% <strong>of</strong> this polythene wasever recovered (Smith, 1997). <strong>The</strong> then <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Environmental <strong>Trust</strong> did much <strong>of</strong> the work.This demonstrates the potential for highly damagingmarine pollution incidents. <strong>The</strong>ir nature may differdepending on the nature <strong>of</strong> the cargo and the ability tocontain oil spills. Spillage <strong>of</strong> oils, plastics or chemicalscould seriously impact marine life particularly sessileintertidal species. Tides, currents and prevailingwinds will influence where the pollution ends up.Clean-up and containment operations after oil spillsare <strong>of</strong>ten more damaging to the marine life than theoil spill itself. <strong>The</strong>y may involve the use <strong>of</strong> chemicaldispersants, hot water or pressure washing <strong>of</strong> theforeshore and widescale trampling.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have been awarded an ‘Area to beavoided’ status (an advisory message to merchantskippers) but sea traffic between <strong>Scilly</strong> and Land’sEnd has greatly increased in recent years and therisk <strong>of</strong> another incident in the future is high (EnglishHeritage, 2004).<strong>The</strong> Emergency Planning Department <strong>of</strong> the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> Council has produced a draft Oil SpillContingency Plan which expands on the NationalContingency Plan from the Maritime and CoastguardAgency (MCA). In the event <strong>of</strong> an oil spill thegovernment has the responsibility for managing thepollution from 1 mile <strong>of</strong>fshore but the local authoritiesare responsible for shoreline clean up. <strong>The</strong> nearestbooms for containing oil are kept by the MCA atTruro but other equipment would have to come fromfurther afield. Methods <strong>of</strong> containing, dispersingand removing the oil are dependent on a number <strong>of</strong>environmental factors and the nature <strong>of</strong> the oil itself.Methods such as high pressure washing and use <strong>of</strong><strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 86

chemical dispersants will only be used for cleaningthe shore following consultation and advice fromconservation organisations. <strong>The</strong> local authorities haveto balance the need to clean the area for tourism withthe potential environmental damage caused by cleanup operations. Any pollution other than oil is theresponsibility <strong>of</strong> the local authorities who would haveto try to claim for the cost <strong>of</strong> the clean up from theship’s insurance company.Plastic rubbish from both distant and local sources isdeposited on <strong>Scilly</strong>’s beaches. This material is verypersistent in the marine environment and can haveunknown effects. Microplastics (tiny fragments <strong>of</strong>broken down plastics) are present in the sands in<strong>Scilly</strong> as they are throughout the World. Some toxinsadhere to plastics and most plastics do not biodegrade,they are simply broken down into fine ‘plastic dust’which can be taken up by filter feeders, potentiallyallowing toxins to enter marine food chains. Plasticalso poses threats to marine life through entanglementor ingestion; furthermore it is unsightly and detractsfrom the beautiful natural scenery in the islands.SewageNutrient enrichment from sewage input or agriculturalrun <strong>of</strong>f can cause problems in the marine environment,disturbing the balance <strong>of</strong> the ecosystem. In <strong>Scilly</strong>there is treatment <strong>of</strong> some sewage to remove nutrientsand debris before discharge. On St Mary’s, OldTown sewage receives treatment at an AcceleratedAerobic Digestion Plant, including UV treatment tokill bacteria such as E.coli. This biobubble treatmentis an effective method <strong>of</strong> nutrient removal. Howeverfor the main centre <strong>of</strong> population, Hugh Town (hometo about 1000 people) the sewage is discharged to thesea untreated (only macerated) via an outfall pipeat Morning Point on the Garrison. Seagulls can beobserved sitting on the slick <strong>of</strong>f the outfall and solidsand sanitary products have been known to wash intoPorth Cressa beach.For more isolated buildings and on the <strong>of</strong>f-islandsthere is no mains sewer so they either have septictanks which can be emptied and discharged to themains or they have a tank and soakaway system. <strong>The</strong>final soakaway <strong>of</strong>ten discharges over cliffs or ontobeaches.Agricultural run <strong>of</strong>fFlowers, bulbs and potatoes are the main crops in<strong>Scilly</strong> where the mild climate confers an advantageover the mainland with the ability to harvest thesecrops far earlier in the season. In the past, nitratebased fertilisers and eelworm killers were usedbut these practices have now ceased. Herbicide isstill used in flower farming and soil erosion cansometimes be observed in newly ridged fields, whichmay mean that soil and herbicides are entering themarine environment. Livestock are not found inhigh concentrations and are usually slaughteredon the mainland. <strong>The</strong>refore run-<strong>of</strong>f from the fieldsprobably has very little negative impact on the marineenvironment (Warwick, BIOMARE questionnaire).Fishing debris(see section 3.3:Fisheries)Nets, fishing crates, lines and other debris from fishing<strong>of</strong>ten ends up on beaches, these items are <strong>of</strong>ten plasticand highly persistent in the environment. Surveys in2007 showed that fishing debris made a significantcontribution to beach litter and accounted for over30% <strong>of</strong> all traceable litter on most beaches surveyed in<strong>Scilly</strong> (Beachwatch, Marine Conservation Society).Refuse DisposalIn the past, refuse from the islands was disposed<strong>of</strong> either by burning or dumping into the sea. Forexample on St Martin’s all the non-burnable rubbishwas tipped over the cliffs at Wine Cove on theuninhabited north side <strong>of</strong> the island. Although thispractice ceased in the late 1990s (English Heritage,2004) there may still be impacts from chemicals andheavy metals which are likely to have accumulated inthe sediments there. In some places where cars weredumped the marine life may have benefited fromincreased settlement space as the vehicles acted as‘artificial reefs’. Any such effect would be fairly shortterm as storms and rust would break up the vehicleswithin a few years.Rubbish is collected from the <strong>of</strong>f-islands and burnablematerials are incinerated, mostly on St Mary’s. <strong>The</strong>re isno reclamation <strong>of</strong> heat or power from the incinerationprocess but emissions are checked by the EnvironmentAgency. Through a project called <strong>Scilly</strong> Waste metaland glass is recycled on St Mary’s and waste reductionmeasures are promoted.Awareness<strong>The</strong> <strong>Scilly</strong> Waste Project aims to raise awareness aboutrecycling and waste minimisation across all sectors <strong>of</strong>society. <strong>The</strong> AONB has been working with the localschools to raise awareness amongst island childrenabout waste awareness with a focus on marine litter.<strong>The</strong>y conduct regular beach cleans with the schoolsduring the summer.Litter left by visitors can make a significantcontribution to beach litter and was found to be thesecond commonest source <strong>of</strong> litter (for litter whichcould be sourced) on Scillonian beaches surveyed in2007 (Beachwatch, Marine Conservation Society).Beachwatch is a project run by the MarineConservation Society involving volunteers in beachlitter surveys and clean-ups. This project has been runin <strong>Scilly</strong> in 2005 and 2007 and the Marine ConservationSociety hopes to continue it there.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 87

3.8 Water ResourcesOverviewWater is key to wide biodiversity; fresh, brackishand seawater all are instrumental in supportingkey species, and wetland and marine habitats arean important part <strong>of</strong> the wider habitat mosaic. Thisis probably more noticeable on island communitieswhere fresh water is <strong>of</strong>ten at a premium.<strong>The</strong>re are no rivers in the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>, althoughthere is a stream on St Mary’s, but each inhabitedisland has a freshwater or brackish pool. Freshwatersprings can be found on most islands, but the watersupply is mainly provided by boreholes, tapping theunderground supply. <strong>The</strong> Council is the last remainingpublic water authority in the UK and is responsiblefor water supply and sewerage on St Mary’s andthe water supply on Bryher. <strong>The</strong> other inhabitedislands rely on private boreholes supplemented withrainwater collection tanks.<strong>The</strong> lack <strong>of</strong> potable water in periods <strong>of</strong> high demandled the Council to invest in a desalination plant for StMary’s in 1992 and this has lessened pressure on watersupply particularly in the peak tourist season.Major Policies, Schemes and Organisations<strong>The</strong> Council for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> has responsibility forthe water supply and works in close cooperation withboth the Duchy <strong>of</strong> <strong>Cornwall</strong> and the Tresco Estate. <strong>The</strong>Duchy has commissioned assessments <strong>of</strong> the watersupply both on St Agnes and St Martin’s where privateboreholes are the major source <strong>of</strong> water; a funding bidthrough Objective One has been obtained to try andimprove the situation on St Agnes.<strong>The</strong>re are water-level management plans for bothLower & Higher Moors produced by the Council forthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.IssuesPollution/Saline IntrusionPollution through agricultural run <strong>of</strong>f is a threat, butnot significant given the lack <strong>of</strong> rivers and groundwater. Saline intrusion, particularly <strong>of</strong> the privateboreholes, is <strong>of</strong> great concern as these are the onlysource <strong>of</strong> water on the <strong>of</strong>f islands. Some <strong>of</strong> the wellsare below sea-level so salt-water intrusion is a concernespecially in droughts, as is contamination from cesspits. It is difficult to take any more from St Mary’saquifer without drawing in more salt.<strong>The</strong> catchment on St Mary’s collects run-<strong>of</strong>f fromagricultural land and the wells at Lower Moors arevery close to the refuse dump. In past at least there hasbeen contamination from pesticides & nitrates.In 2007 some <strong>of</strong> the houses on St Agnes had to usebottled water for drinking as their supply had failedtests.Demand/AvailabilityPeak demand in the high season places a great strainon the water resources when rainfall is at its lowest.This was predominantly the case on St Mary’swhere the majority <strong>of</strong> tourists stay; the building <strong>of</strong> adesalination plant in 1992 has alleviated the problemto some extent, but it does not produce a surplusfor use on other islands. <strong>The</strong> desalination plant onlyproduces approximately half the required water, andis very expensive to run.Climate ChangeIt is anticipated that climate change will lead to moredrought conditions in summer and this will bringfurther pressure on a limited supply <strong>of</strong> fresh water.Agricultural practices may need to be adapted to takeaccount <strong>of</strong> these water shortages and extraction <strong>of</strong>water may lead to drier soil conditions which maylead to a change in the biodiversity <strong>of</strong> terrestrial plantcommunities.Lower Moors on St Mary’s from where some <strong>of</strong> the drinking water is abstracted. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 88

3.9 Climate Change / Sea LevelRiseOverview<strong>The</strong>re has been a growing acceptance that the Earth’sclimate is undergoing change that is significantly atvariance to those changes previously experiencedthroughout its history. Earth history has shown thatclimate has varied between periods <strong>of</strong> Ice Age andlong warmer periods; indeed there has probably beena warmer period in pre-history than that currentlybeing experienced based on examination <strong>of</strong> coresamples <strong>of</strong> soil content. However, there is very strongevidence that the current warming <strong>of</strong> the planet iscaused by CO2 emissions – an anthropogenic effectwhere the change is not part <strong>of</strong> the natural cycle <strong>of</strong>climate variance, but rather that forced by humanactivity.Comprehensive records have been maintained since1914 and the 7 years recorded since 2000 are amongstthe eight warmest on record (Met Office 2007) with2006 having the warmest average temperature(9.84ºC). <strong>The</strong>re are groups, including Greenpeacewho predict that UK temperatures will be on average2.5ºC warmer by 2050 with up to 10% greater rainfall.Extremes in the weather will also be more regularwith storms and flooding occurring at closer intervalsthan previously. Sea levels may rise by 10cm in thesame timescale. <strong>The</strong> geographical position <strong>of</strong> the GulfStream may alter and this could particularly affect the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>.Historical Sea Level Rise for <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>“Exploration <strong>of</strong> a Drowned Landscape”, the 1985study <strong>of</strong> sea level rise by Charles Thomas states thatby 3000BC the islands <strong>of</strong> St Agnes, Annet and theWestern Rocks had become separated from the largerland mass known as Ennor. <strong>The</strong> rest <strong>of</strong> the islandsdid not begin to obtain their current position untilaround the 5th century AD and would still have beenjoined at low tide until the 11th century. This model issomewhat contradicted by the work <strong>of</strong> C J Johns (2001)who claims that the islands were probably separateentities at high water by the late Bronze Age.Whatever theory is taken, the facts are that the islandshave been subject to sea level rise throughout historyand the sea level rise resulting from / associated withclimate change could well further jeopardise the future<strong>of</strong> the islands.Major Policies, Schemes and OrganisationsClimate change is being addressed at a number<strong>of</strong> levels from international to local; a number <strong>of</strong>major conferences and agreements exist from theRio Summit, Kyoto Agreement to the recent UnitedNations climate change conference in Bali.Within the UK, climate change is now a key pillar <strong>of</strong>government policy and the Climate Change Bill 2007will, if ratified, become a defining piece <strong>of</strong> legislationdesigned to reduce carbon dioxide emissions by 20%by 2050.IssuesResearch<strong>The</strong>re are a number <strong>of</strong> differing views as to the causesand effects <strong>of</strong> climate change; it is an evolving sciencethat polarises opinion. Research will need to becontinued as evidence with respect to climate changedevelops. <strong>The</strong> species and habitat mix highlightedas <strong>of</strong> conservation concern in this report will be anevolving tapestry and will need regular and criticalreview.Publications<strong>The</strong> South West <strong>Wildlife</strong> <strong>Trust</strong>s “A Strategy forChange” is a suitable starting point for the assessing <strong>of</strong>how individual trusts can work towards amelioratingthe effects <strong>of</strong> climate change on biodiversity.Sea level rise and increased storminess due to climate change may hasten coastal erosion. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 89

3.10 TourismOverviewTourism is the mainstay <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> economyand present day culture; it generates in excess <strong>of</strong> 85%<strong>of</strong> the islands’ Gross Domestic Product at about £62million annually. <strong>The</strong> growth <strong>of</strong> tourism has directlyinfluenced the improvement in transport and access tothe islands and the high season inter-island travel.In recent years there has been a declining trend inthe number <strong>of</strong> visitors to <strong>Scilly</strong> as the following tableindicates:Year Visitor Numbers2003 123,9592004 125,0762005 117,0322006 104,6822007 104,987Source: Council for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>The</strong> fall in figures represents a reduction in thenumber <strong>of</strong> casual day visitors, particularly duringthe poor summers <strong>of</strong> 2006 and 2007. <strong>The</strong> number <strong>of</strong>longer staying visitors who book ahead has remainedconstant and this reflects the ceiling imposed withlimited accommodation opportunities. <strong>The</strong> position<strong>of</strong> the islands attracts unusual and rare migrant birdsboth in early spring and late autumn and this extendsthe visitor season from mid March to mid November.As well as the birdwatchers, many other visitors citethe environment, countryside and beautiful views astheir reason for visiting. This shows that the <strong>Isles</strong> <strong>of</strong><strong>Scilly</strong> have the attractions within the environment tobring in increasing visitor numbers, but, equally, thiswill place pressures on the same resources they cometo visit. 90 percent <strong>of</strong> visitors, surveyed by the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> Tourist Board in 2005/06, believe that <strong>Scilly</strong>should promote a more environmentally sustainableenvironment.Major Policies, Schemes and Organisations<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Council, Duchy <strong>of</strong> <strong>Cornwall</strong>, TrescoEstates, <strong>Cornwall</strong> County Council and the variouscarriers are the key organisations. <strong>The</strong>y have combinedto form the “Route Partnership” and the first majoroutcome <strong>of</strong> this was obtaining funding for technicalinvestigation and appraisal <strong>of</strong> an upgrade to HughTown Quay; this will allow an all year round freight/passenger service. This proposal has been included inthe Local Plan.Plans for the upgrade <strong>of</strong> all the quays on the <strong>of</strong>f-islandsis also underway and work was being undertaken onSt Agnes Quay, St Martin’s Higher Town quay, Bryherquay in 2007 with planned work on Carn Near onTresco. This work will significantly enhance the interislandtransport for the local community and equallyfor the growing number <strong>of</strong> visitors.<strong>The</strong> Green Tourism Business Scheme has beenpromoted on <strong>Scilly</strong> through the AONB and 9 localbusinesses have received awards under this scheme.<strong>Scilly</strong> has the greatest concentration <strong>of</strong> members <strong>of</strong> thisscheme in the UK.Issues<strong>The</strong>re are a number <strong>of</strong> issues where tourism mayimpact on the wider biodiversity:EconomyAny decline in the environmental quality <strong>of</strong> the islandsthreatens the tourist economy, particularly as manypeople visit the islands for their environmental andscenic qualities.Awareness<strong>The</strong>re is a great opportunity to promote thebiodiversity through the extensive tourist network andthe conservation organisations need to work closelywith the tourist industry to achieve this.Tourist CapacityAccommodation and transport are the key limitersto the number <strong>of</strong> tourists the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> can copewith. <strong>The</strong> traditional ’high’ season has already beenextended into November due to birdwatching, andthe mild climate and wider availability <strong>of</strong> year roundtransport to the islands may well increase the loading.An initiative called Walk <strong>Scilly</strong> promoted by the <strong>Isles</strong><strong>of</strong> <strong>Scilly</strong> Tourist Board also aims to increase visitornumbers during the ‘shoulder’ seasons but has thepotential to increase levels <strong>of</strong> erosion on footpaths.<strong>The</strong>re needs to be awareness that this increaseshould be managed to minimise the impacts on thebiodiversity <strong>of</strong> the islands.DevelopmentMost built development is undertaken out <strong>of</strong> season,although as outlined at Section 3.4, the planningprocess on the islands is particularly stringent. Futuredevelopment for the increasing tourist loading needsto be monitored closely to ensure negative impact onthe environment is minimised.Whilst accommodation on the islands will remainfinite, there is still the issue <strong>of</strong> day visitors which maywell increase as the availability <strong>of</strong> transport improvesyear round.A scuba diver interacting with an inquisitive seal.Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 90

3.11 Economic DevelopmentOverview<strong>The</strong> speed and breadth <strong>of</strong> economic developmentis key to any island’s development. This is no lessthe case for the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and has been fullyaddressed within the Local Plan. It focuses on theneed for sustainable development that takes intoconsideration environmental issues which may impacton biodiversity – in particular the level and size <strong>of</strong> anyfuture built development and a significant increase intourism, both casual day visitors and longer stayingtourists.<strong>The</strong>re are a number <strong>of</strong> initiatives that will influencethe wider economic development <strong>of</strong> the islands andthese are inextricably linked to the topics discussedthroughout Section 3.Major Policies, Schemes and Organisations<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Local Plan (2005)<strong>The</strong> Local Plan lists the following key factors in theeconomic development <strong>of</strong> the islands:To promote employment and economic activity byproviding opportunities for businesses to supportviable communities. Proposals based on the existingeconomic base <strong>of</strong> tourism, agriculture and fishing,as well as the distinctiveness <strong>of</strong> the islands, will besupported in the following cases:· Where such development contributes to thefurther diversification and essentialmodernisation <strong>of</strong> the islands’ economy· Where it demonstrably improves the quality<strong>of</strong> existing tourist accommodation, including that<strong>of</strong> managed camping sites, or potentially extendsthe length <strong>of</strong> the tourist season· Where there is a change <strong>of</strong> use for a larger hotelor guesthouse (in excess <strong>of</strong> 6 bed spaces) toanother form <strong>of</strong> tourist accommodation whichdoes not create an imbalance <strong>of</strong> accommodationavailable to tourists· Where development provides either a hostel orbunkhouse linked to environmentally oreducationally based activities· Where self contained tourist accommodation isprovided as part <strong>of</strong> a farm holding and isnecessarily related to the farm’s continuedviability and overall land management<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> economic development strategyhighlights the vital link between the exceptionalenvironment, tourism and flower farming. It alsoemphasises the need for a high quality and distinctiveresponse to changing markets in tourism andagriculture; both sectors are important to the ongoingand sympathetic management <strong>of</strong> the islands.Boats to the <strong>of</strong>f-islands run from the quay on St Mary’s. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 91

Key Strategic Plans relating to the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>The</strong> following key pieces <strong>of</strong> legislation/strategieswill have an impact on both the islands’ economicdevelopment as well as the wider support <strong>of</strong>biodiversity:· Power <strong>of</strong> Place (English Heritage) – the historicenvironment is a vital resource which playsan indispensable role in the sustainable long termrenewal <strong>of</strong> the islands.· <strong>The</strong> Historic Environment: A Force for OurFuture (DCMS) – looks to the full and totalembracing <strong>of</strong> the historic environment usingit to the benefit <strong>of</strong> the economy and sustainabledevelopment.· Regional Planning Guidance for the SouthWest 2001 (RPG10) – to support communitiesthat are economically prosperous, havedecent homes at affordable prices, safeguardthe countryside and promote a strong sense <strong>of</strong>community.· Draft Regional Spatial Strategy for the SouthWest 2006-2026 (Jun 06) – Policy SR42 dealsspecifically with the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and statesthat the Local development Document should,inter alia, diversify the local economy (whichis heavily dependant on tourism) and protect theenvironment.· <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Landscape Assessment – raiseawareness <strong>of</strong> the AONB and guide policy makersfor the area.· <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> AONB Management Plan– recognised as a centre <strong>of</strong> environmentalexcellence with organisations and the localcommunity working together to conserve andpromote the natural and historic environmentwhist supporting the local economy.· IOS Council Local Plan – as discussed elsewhere· On the Edge : <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Investment Plan,<strong>The</strong> Objective One Integrated Area Plan – toimprove the economic base <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>through appropriate sustainable developmentwhilst protecting and enhancing the uniquenature <strong>of</strong> the Scillonian environment.· <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Transport Strategy “Moving On”– develop a strategy for sustainable transport forthe islands.that tourism is developed in a positive andsustainable way.· <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong>s ManagementPlans – to set out the best management practicesfor the land leased by the <strong>Trust</strong> in order toachieve key conservation objectives.<strong>The</strong> <strong>Cornwall</strong> and <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Economic Forum haspublished the Economic Strategy for <strong>Cornwall</strong> andthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> 2007-2021. This document reviewsthe existing strategy so that it better aligns to theRegional Economic Strategy 2006-2015, and createsthe foundations that will facilitate the delivery <strong>of</strong> EUfunding from 2007 onwards. This document can beviewed at www.economicforum.org.ukIssuesCoherency<strong>The</strong> plethora <strong>of</strong> legislation and strategies in place needto have linkage in objectives in order to ensure:· <strong>The</strong>re is no overlap in use <strong>of</strong> resources· <strong>The</strong>re is no dichotomy in the overall objectives· Confusion is not created with the large number<strong>of</strong> initiatives· Public and business “buy-in” and awareness isachievedFundingFunding opportunities are limited and it is imperativethat all funding obtained is focused toward achievingthe overall wider objectives. Many funding streamsare placing greater emphasis on environmentalimprovement, including biodiversity.<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s unique biodiversity mix willprovide important opportunities to carry out researchand develop expertise in island biodiversity.ThreatsAny decline in the environment or biodiversity mayhave a detrimental impact on the wider economy <strong>of</strong><strong>Scilly</strong>Opportunities<strong>The</strong> potential for economic development strategies andprogrammes to have a positive impact on biodiversityneeds to be fully explored and should remain at theforefront <strong>of</strong> any future planning or proposals.· <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Tourism Strategy – to achievesynergy and coherency in a marketing policy so<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 92

4Priorities for <strong>Biodiversity</strong>Conservation<strong>The</strong> diversity <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’s habitats andspecies provides an essential element <strong>of</strong> the islandscharacter. <strong>The</strong>ir current status should be maintainedor enhanced so that future generations can benefitfrom both the environmental quality and economicopportunities on <strong>of</strong>fer.In order to achieve the best conservation andenhancement <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity and toensure that resources are spent wisely, priorities forboth habitats and species need to be proposed.Extensive consultation with local experts, speciesexperts, amateur recording groups and analysis <strong>of</strong>records held at ERCCIS has allowed the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>’sspecies and habitats to be assessed for priority actionto the best <strong>of</strong> current knowledge.Priorities are decided using specific criteria, to includespecies or habitats which are threatened, decliningor rare or for which the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> have a specialresponsibility.SpeciesSpecies have been added to the priority list if they arepresent in <strong>Scilly</strong> (or expert opinion suggests they arevery likely to be present there) and are:· National BAP species· Red Data Book species· Nationally Rare· Nationally Scarce· Endemic to <strong>Scilly</strong>· Or on the advice <strong>of</strong> species experts293 species have been prioritised.HabitatsHabitats on the priority list are either· National BAP habitats· Or have been added on the advice <strong>of</strong> expertsbecause they are important for <strong>Scilly</strong> but donot fit into the BAP habitat categories.18 habitats have been prioritised.Some <strong>of</strong> the species and habitats are priorities forfurther survey work, and their retention on thepriority lists will depend upon the findings <strong>of</strong> furtherfield surveys or studies.<strong>The</strong> following tables summarise the priority species(Section 4.1) and priority habitats (section 4.2)Botanists on holiday. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 93

4.1 SpeciesThis <strong>Biodiversity</strong> <strong>Audit</strong> identifies species in need <strong>of</strong>some level <strong>of</strong> conservation action. Where possibleconservation <strong>of</strong> these species will be achievedthrough habitat level action, though a few specieswill require special action to ensure their protectionand conservation. For some species it will not bepossible to improve or maintain their status in <strong>Scilly</strong>through local biodiversity action. For those speciesit is expected that action such as political lobbyingand international agreements will occur at regional,national and international level.Species on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> priority list have beenselected because they are nationally important orimportant to <strong>Scilly</strong>.Within the table information is provided, whereknown, on local decline, local rarity and local threatsto help assess priority. Details <strong>of</strong> the species’ habitatis included as well as whether they occur in BAPhabitats. For each species there are recommendedactions which are described in more detail in Section 5.<strong>The</strong>re are 293 species on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> priority list.Key to species priority tableUK PriorityIncreasingRapidly increasingLocal rarityCommonUncommonRareLocal ThreatHighly threatenedThreatenedNone6-49% increase in numbers/range50-100% increase innumbers/rangeSpecies which are locallywidespreadSpecies which are scarce oroccasional in <strong>Scilly</strong>Species which have very fewknown sites or are very littlerecorded in <strong>Scilly</strong>.Species which aresignificantly andimmediately under threatlocally.Species which are locallythreatened to some levelSpecies which are notthreatened locally (althoughthey may be threatenedelsewhere in their range)BAPRDBNRNSNational <strong>Biodiversity</strong> ActionPlan speciesRed Data Book speciesNationally rareNationally scarceLocal decline (within the last 25 years)Rapidly declining 50-100% decline innumbers/rangeDecliningStatic6-49% decline in numbers/range5% increase – 5% decline innumbers/rangeBAP habitatIndicates whether this species normally occurs withina national <strong>Biodiversity</strong> Action Plan habitat in <strong>Scilly</strong>.RecommendationsRecommendation numbers 1-6 are therecommendations found in Section 5.<strong>The</strong> following species list is not intended to becomprehensive and will reflect the level <strong>of</strong> knowledgeand expertise. It must be considered a “live” documentsubject to change and amendment. Gaps in the tablereflect gaps in current knowledge and data on thestatus and threats for these species.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 94

Gracilaria bursa-pastoris A red seaweed NS On rocks in upper sublittoral 4,1Halymenia latifolia A red seaweed NR 4,1Pterosiphonia pennata A red seaweed NS On coralline algae, muddybedrock and pebbles, low waterto 10m, moderate to shelteredcoasts. 4,1Rhodophysema georgei A red seaweed NR Yes On Zostera 4,1Rhodymenia delicatula A red seaweed NR 4,1Schmitzia neapolitana A red seaweed NR Sublittoral 4,1Schmitzia hiscockiana A red seaweed NR Yes Sublittoral to 18 m on mobilesubstrates such as gravel andstones. Often in tide-swept areasor considerable wave exposure.4,1ALGAESpecies Common name UK Priority Local declineAtractophora hypnoides A red seaweed NRLocalrarityLocalthreat BAP habitat Habitat Comments RecommendationOn coralline algae, subtidal to20m 4,1Bornetia secundiflora A red seaweed NROn boulders and rock betweenlow water and 3m depth,moderate to exposed shoresOnlycollectedfrom <strong>Scilly</strong>in UK 4,1Carpomitra costata A brown seaweed NS On sublittoral rocks to over 30m 4,1Cruoria cruoriaeformis A red seaweed BAP Epiphytic on maerl, sublittoral 4,1Cryptonemia lomation A red seaweed NR Probablyconfined to<strong>Scilly</strong> in UK 4,1Dermocorynus montagnei A red seaweed BAP Yes On small stones between 3 and9m and in seagrass beds 4,1Desmarestia dresnayi A brown seaweed NS Uncommon Subtidal to over 30m on stones insand 4,1Gelidiella calcicola A red seaweed NR Maerl associated 4,1Gelidium sesquipedale, G.corneumA red seaweed NR On rocks in sublittoral fringe,very wave exposed sites 4,1Gigartina pistillata A red seaweed NS Confined toSW England4,1<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 95

Geastrum elegans Elegant Earthstar BAP 1Hericium coralloides Coral Tooth BAP 1Acarospora subrufula A Lichen BAP Rare Yes Exposed granitic coastal rocks 1,3Bacidia assulata A Lichen RDB Rare No Tree bark 1Bacidia incompta A Lichen BAP Rare No Tree bark 1Buellia abstracta A Lichen RDB Rare On granite pebbles and smallstonesCatillaria subviridis A Lichen RDB Rare Yes Nutrient-enriched coastal rocks 1Cryptolechia carneolutea A Lichen BAP Rare No Nutrient-enriched tree bark 1Usnea subscabrosa A Lichen RDB Rare Yes Granitic rocks 1,3Wadeana dendrographa A Lichen BAP Rare No Nutrient-enriched tree bark 11MUSHROOMS ANDTOADSTOOLSSpecies Common name UK Priority Local decline Local rarity Local BAP habitat Habitat CommentsRecommendationLICHENSSpecies Common name UK Priority Local decline Local rarity Local BAP habitat Habitat CommentsRecommendationHeterodermia leucomela Ciliate Strap-lichen BAP Uncommon Yes Mossy rocks on exposed coastalcliffsHeterodermiapropaguliferaCoralloid RosettelichenRDB Rare Yes Peaty soil on exposed coastalcliffsLecanora strobilina A Lichen RDB Rare No Conifer tree bark 1Lecidella viridans A Lichen RDB Rare Granitic rocks 1Lecidia sarcogynoides A Lichen RDB Rare Yes Granitic rocks near the sea 1,3Opegrapha prosodea A Lichen BAP Rare No Tree bark 1Pseudocyphellaria aurata A Lichen BAP Declining Rare HighlythreatenedYes Rocks or Ling Calluna vulgaris 2,3Ramalina chondrina A Lichen RDB Rare Yes Coastal siliceous rocks 1Teloschistes flavicans Golden Hair-lichen BAP Uncommon Yes Granitic rocks and associated soil 1,31,31,3<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 96

Eriopus apiculatus A moss RDB Shaded banks Introduced 2MOSSES AND LIVERWORTSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationCephaloziella turneri A liverwort RDB Yes On slightly acidic coastal soil 1,3Fossombronia pusilla varmaritimaGongylanthus ericetorum A liverwortA liverwort RDB Declining Uncommon Threatened Yes On peaty soil <strong>of</strong> heaths andheathy cliffsRDB Static Rare Yes HeathlandLophocolea bispinosa A liverwort RDB Increasing Uncommon Gardens Introduced 2Lophocolea semiteres A liverwortRDB Increasing Uncommon Yes Various, especially pathsides IntroducedRiccia crystallina A liverwort RDB Increasing Uncommon Yes Arable fields and path sides Introduced 2SematophyllumsubstrumulosumSphaerocarpos texanus Texas BalloonwortA moss RDB Increasing Rare No On tree bark 2BAP Static Uncommon Yes Arable fieldsTelaranea murphyae A liverwort RDB Increasing Uncommon Yes Humid sites including wetwoodlandTortula rhizophyllai A mossTortula solmsii A mossTortula wilsonii Wilson`s PottiaRDB Yes On granitic rockRDB Static Rare Yes Low vertical sandy cliffs2,32,32,3Introduced 2BAP Not recorded forover 50 years 122,32,3FLOWERING PLANTSSpecies Common name UK Priority Local decline Local rarity LocalthreatAllium ampeloprasumampeloprasum Wild Leek RDB Static RareBAP habitat Habitat CommentsRecommendationHighlythreatened Yes Rough ground near sea 2<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 97

Ornithopus pinnatus Orange Birdsfoot RDB Static Uncommon Threatened Yes Sandy ground and heathlandEndemic to<strong>Scilly</strong> and<strong>Cornwall</strong> 3Poa infirma Early Meadowgrass NS Increasing Common Threatened Yes Grassland 3,2Polycarpon tetraphyllum Four-leaved Allseed RDB Static Common Threatened Yes Arable fields and waste ground 5Endemic3,2Allium ampeloprasum varbabingtonii Babbington’s Leek NS Static Common Threatened YesMaritime cliffs and slopes andarable areas.Arum italicum neglectum Late Cuckoo-pint NS Static Common None Yes Arable fields and hedgerows 3Asplenium obovatum Lanceolate SpleenwortNS Static CommonHighlythreatened No Walls 3Chamaemelum nobile Chamomile BAP Static Common Threatened Yes Heathland & grasslandErodium moschatum Musk Storksbill NS Static Common Threatened Yes Arable land 5Euphorbia portlandica Portland Spurge NS Static Common Threatened Yes Coastal sand dunes 3Fumaria occidentalis Western Fumitory NS Static Rare HighlythreatenedLathyrus japonicusmaritimus Sea Pea NS Erratic RareLavatera creticaLotus subbiflorusCretan/Smaller TreeMallow RDB Static UncommonHairy BirdsfootClover NS Increasing Common Threatened YesNo Field margins & hedges Endemic to<strong>Scilly</strong> and<strong>Cornwall</strong> 5,2Highlythreatened Yes Sand and gravel beaches 2Highlythreatened Yes Arable fields 5Heathland and coastal sanddunes 3Medicago polymorpha Toothed Medick NS Static Uncommon Threatened Yes Arable fields and maritime cliffs 3Oenanthe fistulosa Tubular WaterdropwortBAP Declining Rare HighlythreatenedOphioglossum azoricum Small Adderstongue NS Declining UncommonOphioglossumlusitanicumLeast AdderstongueFern RDBYes Wet fields & ditchesHighlythreatened Yes Heathland and coastal grassland 3Static Rare Threatened Yes Short turf on coastal heathland Endemic1,33,23Polygonum maritimum Sea Knotgrass RDB Erratic Rare Threatened Yes Beaches 2Rumex rupestris Shore Dock BAP RapidlydecliningRare HighlythreatenedYes Upper rocky shores & base <strong>of</strong>cliffs 2,3<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 98

Spergularia bocconei Greek Spurrey RDB Rare Threatened No Coastal bare ground 1Trifolium glomerata Clustered Clover NS Static Rare Threatened Yes Arable, acid grassland 5Trifolium occidentale Western Clover NS Static Common Threatened Yes Maritime cliffs and slopes 3Axinella infundibuliformis A sponge NR Shallow sublittoral rock 4,1Crella rosea A sponge NS 4,1Desmacidon fruticosum A sponge NR 4,1Homaxinella subdola A sponge NS 4,1Tethyspira spinosa A sponge NS 4,1Salsola kali kali Prickly Saltwort BAP RapidlydecliningScandix pecten-veneris Shepherd’s Needle BAP RapidlydecliningRare HighlythreatenedRare HighlythreatenedScrophularia scorodonia Balm-leaved Figwort NS Static Common Threatened YesSibthorpia europea Cornish Moneywort NS Declining RareSilene gallica Small FloweredCatchflyYes Sandy beachesYes Bulb fieldsCoastalHighlythreatened No Streams and ditches 2,5BAP Static Common Threatened Arable & disturbed ground2,3533Trifolium suffocatum Suffocated Clover NS Static Rare Threatened YesAcid grassland, maritime cliffsand slopes 3Vicia bithynica Bithynican Vetch NS/VU Declining RareViola kitabeliana Dwarf Pansy RDB/NT Static RareZostera spp Seagrass BAP(habitat)Highlythreatened No Arable fields 5Highlythreatened Yes Dune grassland Endemic 3,2Declining Common Threatened Yes Seagrass beds4,2SPONGESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationAdreus fascicularis A sponge NS Rare 4,1Axinella damicornis A sponge NS Common YesOn rock faces with moderatewave action below 20m 4,1<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 99

Alcyonium hibernicum Pink Sea Fingers NS Uncommon On shaded vertical or 4,1Amphianthus dohrnii Sea-fan Anemone BAP Rare Yes On Eunicella verrucosa 4,2Anthopleura thallia Glaucus Pimplet NS Yes On rocky shores exposed tostrong wave action, in pools,crevices, or amongst denseaggregations <strong>of</strong> musselsIntroduced 4,1CNIDARIASpecies Common name UK Priority Local decline Local rarity LocalthreatAglaophenia kirchenpaueri A hydroid NS RareAiptasia mutabilis Trumpet Anemone NS UncommonBAP habitat Habitat CommentsRecommendationFound on hard substrata, theseaweed Cystoseira spp. andcoralline algae on the lower shoreand shallow sublittoral 4,1On shore or in depths down to100m or more. On rocks, seaweedholdfasts 4,1Balanophyllia regiaScarlet and Gold CupCoral NS RareCataphellia brodricii Latticed Corklet NSEdwardsia timidaTimid BurrowingAnemone BAP YesOn rocks in caves, gullies andoverhangs. From shallowsublittoral to 20m 4,1Amongst algal holdfasts fromlower shore to 20m 4,1Intertidal and shallow subtidalsediment 4,1Eunicella verrucosa Pink Sea-fan BAP Uncommon Yes Rocky reefs 4,2Haliclystus auricula A stalked jellyfish BAP Uncommon YesHoplangia durotrixWeymouth CarpetCoral NR RareOn algae and seagrass in the lowintertidal and shallow sublittoral 4,1On rocks, in caves and crevices,shallow sublittoral to 25m 4,1Laomedea angulata A hydroid NS Rare Yes In seagrass 4,1Leptopsammia pruvoti Sunset Cup Coral BAP RareOn rocks in clefts and overhangs,shallow sublittoral to 30m 4,1<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 100

Lucernariopsiscampanulata A stalked jellyfish BAP Common YesOn algae and seagrass in the lowintertidal and shallow sublittoral 4,1Lucernariopsiscruxmelitensis A stalked jellyfish BAP YesParazoanthus axinellaeOn algae and seagrass in the lowintertidal and shallow sublittoral 4,1Yellow ClusterAnemone NS Yes On rocks from 5-50m 4,1SPIDERSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationClubiona genevensis A spider RDB Rare Yes Coastal grassland and heathland 1Dipoena inornata Silky Gallows-spider BAP Not recordedsince 1929Rare /extinctYes Heathland 1CRUSTACEANSSpecies Common name UK Priority Local decline Local rarity LocalthreatAchaeus cranchii Cranch’s Spider Crab NRAmpherusa clevei An amphipod NR NoBAP habitat Habitat CommentsRecommendationOn subtidal hydroids, bryozoansand seasquirts 4,1In surface plankton andsublittoral algae 4,1Apherusa ovalipes An amphipod NS In sublittoral algae 4,1Microdeutopus stationis An amphipod NRPalinurus elephasIn kelp holdfasts from low waterto 50m 4,1Crayfish, Crawfish orSpiny Lobster BAP Declining Rare Yes Circalittoral exposed rocky reefs 4,2Pereionotus testudo An amphipod NR Yes Intertidal, in rockpools 4,1Synisoma lancifer A sea slater NSTypton spongicola Sponge Shrimp NR YesIn algae and under stones nearlow water 4,1In sponges between 10-100mdepth 4,1<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 101

Recommendation1RecommendationCENTIPEDES ANDMILLIPEDESSpecies Common name UK Priority Local decline Local rarity LocalthreatNothogeophilus turki Turk’s EarthcentipedeBAP habitat Habitat CommentsBAP Rare Endemicsub-species,populationfluctuatesCRICKETS,GRASSHOPPERSAND RELATIVESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsAcanthoxyla geisovii A Stick insect RDB Static Introduced 2Clitarchus hookeri Smooth stick insect RDB Static Introduced 2Ectobius panzeri Lesser Cockroach NS YesCoastal heathers and ThriftArmeria maritima 2,3Forficula lesnei Lesne’s Earwig Yes Under coastal herbs 2,3BUGSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsDicranocephalus agilis A spurge bug NS Static Common None Yes Portland Spurge Euphorbiaportlandica and Sea Spurge E.paralias on coastlandRecommendationEmblethis verbasci A ground-bug RDB Static Uncommon None Yes Coastal sandy areas 2,3Piesma quadratumspergulariaeA beet-bug RDB Static Uncommon None Yes Rock Sea-spurrey Spergulariarupicola on coastlandStrongylocoris luridus A capsid bug NS Static Common None Sheep’s-bit Jasione montana oncliffs/old walls<strong>Scilly</strong> is astronghold2,32,32,3<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 102

Agrochola lychnidis Beaded Chestnut BAP Rare Yes Woodland and heathland. Larvalfoodplant: herbaceous plantsAgrotis puta insula Larval foodplant: low-growingShuttle-shaped Dart Common Yes Low-lying marshy ground.plantsAmphipoea oculea Ear Moth BAP Rare Various damp habitats. Larvalfoodplant: various grassesAmphipyra tragopoginis Mouse Moth BAP Rare A range <strong>of</strong> habitats. Larvalfoodplant: herbaceous plantsApamea remissa Larval foodplant: a range <strong>of</strong>Dusky Brocade BAP Uncommon Woodland, pasture and marsh.grassesArctia caja Garden Tiger BAP Common Various habitats. Larvalfoodplant: various plantsBembecia muscaeformis Thrift Clearwing NS Uncommon Yes Coastal areas. Larval foodplant:thrift Armeria maritimaCaradrina morpheus Mottled Rustic BAP Rare Larval foodplant: nettle Urticadioica and othersCelaena leucostigma <strong>The</strong> Crescent BAP Rare Yes Fens and marshy ground. Larvalfoodplant: marshy plants such asyellow flag Iris pseudacorus<strong>Scilly</strong> is astrongholdEndemic to<strong>Scilly</strong><strong>Scilly</strong> is astrongholdRecommendation121121122111BUTTERFLIES ANDMOTHSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsAcronicta psi foodplant: various trees andGrey Dagger BAP Rare No Parkland and gardens. LarvalshrubsAcronicta rumicis Knot Grass BAP Common No Woodland and gardens. Larvalfoodplant: willow, hawthorn etcAgrochola litura Brown-spot Pinion BAP Rare Yes Woodland and heathland. Larvalfoodplant: herbaceous plantsEndemicsub-speciesEndemicsub-species<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 103

Mesoligia literosa Rosy Minor BAP Rare Yes Coastal areas. Larval foodplant:various grassesNothris congressariella A moth RDB Rare Yes Disturbed ground and dunes.Larval foodplant: balm-leavedfigwort (Scrophularia scorodonia)Oinophila v-flava Yellow V Moth RDB Rare Larval foodplant: dry vegetablematterOrthosia gracilis Powdered Quaker BAP Rare Found in woodland andparkland areas. Larval foodplant:certain wetland plants, willow etcPararge aegeria insula Speckled Wood BAP Common Areas within woodlands,parkland and shady lanes. Larvalfoodplant: various grasses.Scopula marginepunctata Mullein Wave BAP Uncommon Yes Coastal areas. Larval foodplant:low growing plants such asyarrow Achillea millefolium<strong>Scilly</strong> isstronghold212,32212,31,31,31122,3Diarsia rubi Small Square-spot BAP Common Various damp and marshyplaces. Larval foodplant:herbaceous plantsEcliptopera silaceata Small Phoenix BAP Rare A range <strong>of</strong> woodland and moreopen areas. Larval foodplant:willowherbs Epilobium sppEumichtis licheneascilloneaFeathered Ranunculus Common Yes Coastal areas. Larval foodplant:low plantsHoplodrina blanda <strong>The</strong> Rustic BAP Common Larval foodplant: various lowplantsHydraecia micacea Rosy Rustic BAP Common Waste ground: Larval foodplant:docks Rumex sppMelanchra persicariae Larval foodplant: a wide range <strong>of</strong>Dot Moth BAP Rare Waste ground and gardens.plantsMelanchra pisi Broom Moth BAP Uncommon Yes Open woodland and heathland.Larval foodplant: broom Cytisusscoparius and others<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 104

Aphrosylus mitis A fly NS Uncommon Intertidal seashore 1Bombus jonellus Heath Bumblebee RDB Declining Uncommon Yes Coastal heathland and grassland 2,3Bombus muscorumscyllonius Moss Carder-bee BAP Static Uncommon Yes Coastal heathland and grassland 2,3Formica rufibarbis Red-barbed Ant BAP Static Uncommon Threatened Yes Coastal heathland and grassland 2,3Spilosoma lubricipeda plants such as water mint MenthaWhite Ermine BAP Common Yes Fens. Larval foodplant: marshaquaticaSpilosoma luteum Buff Ermine BAP Common Larval foodplant: herbaceousplants, shrubs and treesTimandra comae Blood-vein BAP Rare Larval foodplant: low-growingplants such as docks Rumex sppTyria jacobaeae ragwort Senecio jacobaea and<strong>The</strong> Cinnabar BAP Common Grasslands. Larval foodplant:othersXanthia icteritia <strong>The</strong> Sallow BAP Rare Yes Damp woodland, marsh andheathland. Larval foodplant:sallow and herbaceous plantsXanthorhoe ferrugataDark-barred TwinspotCarpetBAP Uncommon Widespread. Larval foodplant: avariety <strong>of</strong> low plants 222121TWO WINGED FLIESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationWASPS AND BEESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationANTSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendation<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 105

Chrysolina graminis vulgare or Water Mint MenthaTansy Leaf-beetle NS Declining Rare Associated with Tansy TanacetumaquaticaMeloe proscarabaeus Black Oil-beetle BAP Uncommon Yes Coastland 2,3Psylliodes hyoscanii A beetle RDB Rare Associated with HenbaneHyoscyamus nigerSilpha obscura A beetle RDB Rare Yes Sandy grassland 1,321BEETLESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationCathormiocerus maritimus A weevil RDB Rare Yes Grazed sea-cliffs 1,3CathormiocerusmyrmecophilusA weevil RDB Rare Yes Grazed sea-cliffs 1,3MOLLUSCSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsAcanthocardia aculeata Spiny Cockle NR Yes Sublittoral muddy sands <strong>Scilly</strong> one<strong>of</strong> 4 knownsites inEnglandAtagema gibba A sea slug NR Steep rock faces, 8-15m depth Onlyknown from<strong>Cornwall</strong> &<strong>Scilly</strong> in UKRecommendation4,14,1Atrina fragilis Fan Mussel BAP Rare /locallyextinct?No Lower intertidal mud, sandymud or gravelBittium simplex A sea snail NR 4,1Callista chione Smooth Venus NR Yes Sand to a depth <strong>of</strong> 100m Only 4known sitesin England4,14,1<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 106

RecommendationRecommendationRecommendationAmmodytes marinus Lesser Sand Eel BAP Common Yes Subtidal s<strong>of</strong>t sediment 4Anguilla anguilla European Eel BAP Common Marine, brackish and freshwater 4Cetorhinus maximus Basking Shark BAP Common Threatened No Open water 4,2Doris sticta A sea slug NR 4,1Gastrochaena dubia A flask shell 4,1Jujubinus striatus Grooved Topshell NR Declining Yes On seagrass 4,2Leptochiton scabridus A chiton NS YesOstrea edulis Native Oyster BAP Declining Rare YesExtreme low water and subtidalsand, stones and pebbles 4,1Shallow coastal areas with firmsand, rocks or gravel 4,2Paludinella littorina Lagoon snail Uncommon Cracks in supralittoral rock 2Trapania pallida A sea slug NS 4,1Tritonia nilsodneri Sea Fan Sea Slug NS Rare Yes On pink sea fans 4,2BRYOZOASpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsTurbicelleporamagnicostataLace Coral / OrangePeel Seamat NR Common None Exposed coasts 4Watersipora complanata NR Intertidal 4,1TUNICATESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsMolgula oculata A seasquirt NS Yes Bays with clean sand or gravel 4,1Phallusia mammillata A seasquirt NSPycnoclavella aurilucensOrange LightsSeasquirt NSHard substrate with little watermovement 4,1In the kelp zone to 30m, in strongwater movement 4,1FISHSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat Comments<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 107

Clupea harengus Herring BAP Common Threatened No Pelagic, 0-200m 4Gadus morhua Cod BAP Common Threatened No Open water 4Hippoglossus hippoglossusAtlantic Halibut BAP Rare Mostly demersal below 100m 4Isurus oxyrinchus Shortfin Mako BAP Rare Threatened No Open water 4,2Lamna nasus Porbeagle Shark BAP Common Threatened No Open water 4,2Merluccius merluccius European Hake BAP Common Threatened Demersal 4Micromesistus poutassou Blue Whiting BAP Uncommon Threatened Pelagic between 300 and 400m 4Molva molva Ling BAP Common Threatened Yes Rocky areas below 10m 4Coryphaenoides rupestris Grenadier BAP Rare No Deep water 4Dalatias licha Kitefin Shark BAP Rare No Deep water 4,2Dipturus batis Common Skate BAP Threatened YesSand and mud in coastal shelfwaters 4Galeorhinus galeus Tope Shark BAP Common Threatened No Open water 4,2Gobius cobitis Giant Goby NS None YesHippocampus guttulatus(H. ramulosus)HippocampushippocampusLong SnoutedSeahorse BAP Rare Threatened YesShort SnoutedSeahorse BAP Rare Threatened YesSheltered rocky shores, highintertidal pools 4,1Shallow water in seagrass bedsand algae 1,4Shallow muddy or rocky areas inseagrass or algae 1,4Leucoraja circularis Sandy Ray BAP Rare Threatened Demersal 4Lophius piscatorius Sea Monkfish BAP Threatened YesMerlangius merlangus Whiting BAP Common Threatened YesDemersal, from low intertidal todeep water, mainly on sand andmud 4Demersal on sand, gravel androcks down to 200m 4<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 108

Prionace glauca Blue Shark BAP Common Threatened No Open water 4,2Salmo salar Atlantic Salmon BAP Common Threatened No Open water, estuaries and rivers 4Salmo trutta Brown/Sea Trout BAP Common Threatened No Open water, estuaries and rivers 4Scomber scombrus Mackerel BAP Common Threatened No Open water 4Solea solea Dover Sole BAP Declining Common Threatened Demersal 4RecommendationAnguis fragilis Slow worm BAP Rare No Hedgerows/boundaies Introduced 2,3RecommendationCaretta caretta Loggerhead Turtle BAP Rare Threatened No Open water 4,2Parablennius ruber Red Blenny NR Increasing? Rare NonePleuronectes platessa Plaice BAP Common ThreatenedBedrock and boulders between15m and 30m 4,2Demersal on sand, gravel or mudat depths between 10-50m 4Raja undulata Undulate Ray BAP Uncommon Threatened Demersal 4Rostroraja albaWhite or BottlenosedSkate BAP Uncommon Threatened Demersal between 40 and 400m 4Squalus acanthias Spiny Dogfish BAP Common Threatened Surface to 900m 4Squatina squatina Angel Shark BAP Uncommon Threatened YesDemersal over mud and sand to150m 4,1Thunnus thunnus Bluefin Tuna BAP Rare No Open water 4Trachurus trachurusHorse Mackerel /scad BAP Declining Rare No Open water 4TERRESTRIALREPTILESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsMARINE REPTILESSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat Comments<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 109

Dermochelys coriacea Leatherback Turtle BAP Rare Threatened No Open water 4,2Lepidochelys kempii Kemps Ridley Turtle BAP Rare Threatened No Open waterOutsidenaturalrange 4,2BIRDSSpecies Common name UK Priority Local decline Local rarity LocalthreatBAP habitat Habitat CommentsRecommendationAcrocephalus paludicola Aquatic Warbler BAP Static Rare Yes Fens 2Acrocephalus palustris Marsh Warbler BAP Static Rare Yes Fens 2Alauda arvensis arvensis/scoticaSky Lark BAP Declining Uncommon Yes Arable Fields/Grassland2Anser albifrons albifrons European GreaterWhite-fronted GooseAnser albifrons flavirostrisGreenland GreaterWhite-fronted GooseBAP Static Rare Yes Coastal land and agriculturalland 2BAP Static Rare Yes Coastal land and agriculturalland 2Anthus trivialis Tree Pipit BAP Static Uncommon Various 2Aythya marila Greater Scaup BAP Static Uncommon No Freshwater and inshore waters 2Botaurus stellaris Great Bittern BAP Static Rare Yes Reedbeds 2Branta bernicla bernicla Dark-bellied BrentGooseBAP Increasing Uncommon Coastal land and inshore watersBurhinus oedicnemus Stone-curlew BAP Static Rare Various 2Caprimulgus europaeus European Nightjar BAP Static Rare Various 2Carduelis cabaret Lesser Redpoll BAP Increasing Uncommon Parkland and woodland 2Carduelis cannabinaautochthona/cannabinaCarduelis flavirostrisbensonorum/pipilansCharadrius hiaticula Common RingedPloverCoccothraustescoccothraustesCommon Linnet BAP Declining Common Scrub and agricultural land.Twite BAP Static Rare VariousDeclining Uncommon HighlythreatenedHawfinch BAP Static Rare VariousYes Coastal land: breeds on shingleCrex crex Corn Crake BAP Static Rare Various 2Cuculus canorus Common Cuckoo BAP Declining Uncommon Yes Coastal land 222222<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 110

22Cygnus columbianusbewickiiTundra Swan BAP Static Rare Yes FreshwaterEmberiza citrinella Yellowhammer BAP Static Uncommon Various 2Emberiza schoeniclus Reed Bunting BAP Static Uncommon Yes Fens 2Fratercula arctica Atlantic Puffin Increasing Uncommon Threatened Yes Uninhabited islands andadjacent seas 2,4Gavia arctica Black-throated Diver BAP Static Uncommon No Inshore waters 2Hydrobates pelagicus European Storm Petrel Static Common HighlythreatenedYes Uninhabited islands andadjacent seas 2,4Jynx torquilla Eurasian Wryneck BAP Increasing Uncommon Various 2Lanius collurio Red-backed Shrike BAP Increasing Uncommon Various 2Larus argentatusargenteusLarus fuscus Lesser Black-backedGullLarus marinus Great Black-backedGullHerring Gull BAP RapidlydecliningCommon Yes Breeds mainly on maritime cliffsDeclining Common Yes Breeds mainly on <strong>of</strong>fshoreislands 2,3Declining Common Yes Breeds mainly on maritime cliffsLimosa limosa limosa Black-tailed Godwit BAP Increasing Uncommon Yes Coastal land 2Locustella naevia Common Grasshopper BAP Static Uncommon VariousWarblerLullula arborea Wood Lark BAP Static Uncommon Various 2Melanitta nigra Common Scoter BAP Increasing Uncommon No Inshore waters 2Miliaria calandracalandra/clanceyiCorn Bunting BAP Declining Rare VariousMotacilla flava flavissima Yellow Wagtail BAP Static Uncommon Various2,32,322Muscicapa striata Spotted Flycatcher BAP Declining Uncommon No Woodland edges 2Numenius arquata Eurasian Curlew BAP Static Common Yes Coastal land 2Passer domesticus House Sparrow BAP Static Common Built-up areas 2Passer montanus Eurasian TreeSparrowBAP Static Rare Yes Agricultural land.Phalacrocorax aristotelis European Shag Static Common Yes Maritime coast and adjacent seas22,4Phalaropus lobatus Red-necked Phalarope BAP Static Rare Yes Freshwater2<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 111

Sturnus vulgaris vulgaris Common Starling BAP Increasing Common Yes Built-up areas and farmlandTurdus philomelos clarkei Song Thrush BAP Static Common Yes Gardens and the wideragricultural landscape 2Nyctalus noctula Noctule BAP Uncommon Threatened Various 2,3Pipistrellus pygmaeus Soprano Pipistrelle BAP Uncommon Threatened Various 2,322Phylloscopus sibilatrix Wood Warbler BAP Static Uncommon No Various 2Prunella modularisoccidentalisHedge Accentor BAP Static Common No Gardens and other scrubPuffinus mauretanicus Balearic Shearwater BAP Increasing Uncommon Yes Offshore waters 2Pyrrhula pyrrhula pileata Common Bullfinch BAP Static Rare No Scrub and gardens2Stercorarius parasiticus Arctic Skua BAP Static Uncommon No Offshore waters 2Sterna dougallii Roseate Tern BAP RapidlydecliningSterna hirundo Common Tern RapidlydecliningRare HighlythreatenedUncommon HighlythreatenedSterna paradisaea Arctic Tern Static Rare HighlythreatenedSterna sandvicensis Sandwich Tern Declining Uncommon HighlythreatenedStreptopelia turtur European Turtle Dove BAP Declining Uncommon VariousYes Inshore waters: generally breedson undisturbed coastal sites 2,3Yes Inshore waters: generally breedson undisturbed coastal sites 2,3Yes Inshore waters: generally breedson undisturbed coastal sites 2,3Yes Inshore waters: generally breedson undisturbed coastal sites 2,32TERRESTRIALMAMMALSSpecies Common name UK Priority Local decline Local rarity LocalthreatCrocidura suaveolensBAP habitat Habitat CommentsRecommendationLesser white toothedshrew Common None Yes Most terrestrial habitats 2,3Erinaceus europaeus Hedgehog BAP Uncommon None Hedges Introduced 2,3<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 112

RecommendationMARINE MAMMALSSpecies Common name UK Priority Local decline Local rarity LocalthreatHabitat CommentsBalaenoptera acutorostrata Minke Whale BAP Rare No Open water 4,2Balaenoptera borealis Sei Whale BAP Rare No Open water 4,2Balaenoptera musculus Blue Whale BAP Rare No Open water 4,2Balaenoptera physalus Fin Whale BAP Rare No Open water 4,2Delphinus delphis Common Dolphin BAP Uncommon No Open water 4,2Globicephala melas(melaena)Long-finned PilotWhale BAP Rare No Open water 4,2Grampus griseus Risso`s Dolphin BAP Uncommon No Open water 4,2Halichoerus grypus Grey seal Common Threatened No Rocks and coastal waters 4,2LagenorhynchusalbirostrisWhite-beakedDolphin BAP Rare No Open water 4,2Megaptera novaeangliae Humpback Whale BAP Rare No Open water 4,2Orcinus orca Killer Whale BAP Rare No Open water 4,2Phoca vitulina Common Seal BAP Rare Threatened No Rocks and coastal waters 4,2Phocoena phocoena Harbour Porpoise BAP Declining CommonStenella coeruleoalba Striped Dolphin BAP RareTursiops truncatus Bottlenosed Dolphin BAP UncommonHighlythreatened No Coastal and open waters 4,2Highlythreatened No Open water 4,2Highlythreatened No Open water 4,2<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 113

4.2 Habitats<strong>The</strong> conservation <strong>of</strong> habitats and habitat complexes isregarded as fundamental to conserving biodiversity;many conservation processes and actions nowtend towards landscape scale projects rather thanconcentrate on individual species which could haveled to the wider detriment <strong>of</strong> other species. A number<strong>of</strong> habitats have been identified as priorities forthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and most appear as national BAPhabitats on the recently revised 2007 list.species. A number <strong>of</strong> habitats have been id<strong>of</strong> <strong>Scilly</strong> and most appear as national BAP h2007 list.<strong>The</strong> stone hedges in <strong>Scilly</strong> are unique and notrepresented Prioritisation under the BAP <strong>of</strong> system. Habitats Likewise on the <strong>Isles</strong> <strong>of</strong> Scillowland unimproved grassland (other than the acidgrassland) <strong>The</strong> does <strong>Isles</strong> not match <strong>of</strong> <strong>Scilly</strong> any cover <strong>of</strong> the BAP a very habitat small area andcategories,audityet isalsoveryidentifiesimportant2toother habitatimportantmosaichabitats win <strong>Scilly</strong>.<strong>The</strong> following<strong>The</strong>habitatstonelisthedgesreflectsinthe<strong>Scilly</strong>currentarelevelunique<strong>of</strong>and notknowledge system. and understanding Likewise the <strong>of</strong> habitats lowland in unimproved <strong>Scilly</strong>. grasIt must be grassland) considered a does “live” not document match subject any <strong>of</strong> to the BAP habchange and important amendment. to the habitat mosaic in <strong>Scilly</strong>.Prioritisation <strong>of</strong> Habitats on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Priority List<strong>The</strong> <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> cover a very small area and yetcontain 16 BAP habitats. This audit also identifies 2other important habitats which are key to the area.BAP HABITATSHabitatApproximate Importance Status Comments Recommenarea (ha) in <strong>Scilly</strong>dationsLowland Dry Present: prob. Stable 3Acid Grassland small (

5Recommendationsfor Action<strong>The</strong> role <strong>of</strong> this <strong>Biodiversity</strong> <strong>Audit</strong> is to highlightthe priorities for biodiversity conservation in the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> and make recommendations forimmediate action. <strong>The</strong> following recommendationsare proposals for action based upon the prioritiesidentified in Section 4. Where possible, theproduction and implementation <strong>of</strong> action plans willutilise existing mechanisms <strong>of</strong> delivery.<strong>The</strong>se recommendations are for biodiversityconservation at a local level; many <strong>of</strong> the identifiedpriority habitats and species will also be targeted forbiodiversity action at regional and national levels.When feasible, local and higher level biodiversityaction should not be exclusive, each should support,inform and extend the other.<strong>The</strong> production <strong>of</strong> these recommendations was basedon experience from <strong>Cornwall</strong>’s <strong>Biodiversity</strong> Initiativeand on the latest ideas from the national <strong>Biodiversity</strong>Reporting and Information Group about deliverymechanisms.Public AwarenessExperience from <strong>Cornwall</strong>’s <strong>Biodiversity</strong> Initiativeindicates that creating public awareness for its ownsake can divert resources away from achievingconservation goals and has less impact than whencreating public awareness is embedded in otherprojects. <strong>The</strong>refore public awareness is a cross-cuttingtheme in this biodiversity audit. It has not beenidentified as a recommendation because it is assumedthat all biodiversity action will include an element <strong>of</strong>public awareness.Clearly it is crucial that the public are kept informedand engaged with the work stemming from this<strong>Biodiversity</strong> <strong>Audit</strong> and this should be consideredthroughout the planning <strong>of</strong> future work.Stakeholder engagement has been initiated at anearly stage in this process through consultationwith key informants in the local community andthrough progress reports during the production <strong>of</strong> the<strong>Biodiversity</strong> <strong>Audit</strong> on the local radio station.It must be stressed that local ownership andunderstanding <strong>of</strong> the ideas in this document and thework which will follow are key to ensuring its success.Public awareness refers not only to local communitiesbut also to visitors to <strong>Scilly</strong> and other key stakeholderssuch as businesses, councils etc. Outreach work mustidentify and target each group. Many visitors cometo <strong>Scilly</strong> because <strong>of</strong> the natural environment and itshould be possible to successfully conduct outreach inthe short time they may be visiting.Concepts such as the use <strong>of</strong> flagship species canbe useful and <strong>Scilly</strong> has a number <strong>of</strong> eye-catching,charismatic species which can be used to excitestakeholders about the environment.Lobbying local and central government to improve orchange policy relating to conservation is important,particularly for migratory or wide ranging speciesfor which local biodiversity action alone cannotachieve improvements in their status. Furthermore fornational legislation such as the Marine Bill which willeventually have wide reaching implications even at alocal level it is important to support lobbying groups.In summary public awareness at all levels is a themewhich underpins this <strong>Biodiversity</strong> <strong>Audit</strong>.<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 115Corn marigold Chrysanthemum segetum. Photo: Rosemary Parslow

RecommendationsRecommendation 1 – SurveyPromote and instigate survey work for those speciesand habitats on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> priority lists inSection 4 which need further research to establish theirlocal conservation needs and status.<strong>The</strong> priority tables in Sections 4.1 and 4.2 illustrate thelarge gaps in our knowledge about many species andhabitats. For these species and habitats further surveywork is required in order to determine their level <strong>of</strong>significance to <strong>Scilly</strong>. Once this has been established,a decision can be reached as to whether they shouldremain on the priority list.Research into local rarity and threats will help toestablish whether these species need prioritisation.Baseline data is lacking for many species and habitatsagainst which to measure change. Initial habitatmapping <strong>of</strong> many <strong>of</strong> the priority habitats is stillneeded in order to measure changes in the extent <strong>of</strong>habitats and for planning habitat management.Recommendation 2 – Monitor and ResearchSupport and instigate monitoring and research <strong>of</strong>species and habitats on the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> priority list.Monitoring <strong>of</strong> priority habitats and species isrecommended particularly where local threats havebeen identified. <strong>The</strong>re is some monitoring currently inplace and this should be supported and extended toother habitats and species as identified in the tables inSections 4.1 and 4.2.Further research and recording <strong>of</strong> priority speciesand habitats should be encouraged. This includesassisting where possible towards the completion <strong>of</strong>the All Taxon <strong>Biodiversity</strong> Inventory for the marinelife <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>. <strong>The</strong> production <strong>of</strong> a <strong>Scilly</strong>Rare Plants Register similar to that being producedfor <strong>Cornwall</strong> is recommended in order to provide amore complete picture <strong>of</strong> the rare and special florain <strong>Scilly</strong>. It is further recommended that a satellite <strong>of</strong>the Environmental Records Centre for <strong>Cornwall</strong> andthe <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> is established on <strong>Scilly</strong> to supportmonitoring efforts and promote biological recording ingeneral.actions outlined in this report and will make asignificant contribution to the achievement <strong>of</strong> many <strong>of</strong>the other key recommendations.Recommendation 4 – Marine Protected AreaWork towards the inclusion <strong>of</strong> the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> ina South West or National Marine Protected Areanetwork.Marine Protected Areas are a simple way <strong>of</strong> managingresource use in the marine environment, providingprotection for the entire ecosystem. Along with othermeasures a network <strong>of</strong> MPAs can reduce pressure andpromote recovery <strong>of</strong> biodiversity.Recommendation 5 – Additional PlansConsider producing separate Action andImplementation Plans for those species and habitatsnot covered under recommendations 1 to 4.Priority habitats and species which fall outside theIoSWT holdings and any Marine Protected Area that isestablished should be considered for the production <strong>of</strong>separate Action and Implementation Plans. Experiencefrom <strong>Cornwall</strong>’s <strong>Biodiversity</strong> Initiative has shownthat the number <strong>of</strong> separate plans should be kept toa minimum. Where priority species occur within apriority habitat their conservation should be achievedthrough the habitat action and implementation plan.Recommendation 6 – Conservation Advisory GroupMaintain the Conservation Advisory Group for the<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> as a focus for delivering biodiversityaction on <strong>Scilly</strong>.<strong>The</strong> Conservation Advisory Group should takeownership <strong>of</strong> this <strong>Biodiversity</strong> <strong>Audit</strong> and beresponsible for its delivery. Resources should besought to ensure that these recommendations canbe taken forward into programmes <strong>of</strong> work andthat their actions can be achieved. <strong>The</strong>re may bea need to produce a further volume which buildson this <strong>Biodiversity</strong> <strong>Audit</strong> to detail how theserecommendations can be implemented. Best practiceshould be shared between this group and theequivalent group in <strong>Cornwall</strong>.Recommendation 3 – Manage IoSWT land holdingsImplement, maintain and monitor the work plansoutlined in the Management Plans for <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong><strong>Wildlife</strong> <strong>Trust</strong> holdings produced in conjunction withthis report.Management Plans for all the <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong><strong>Trust</strong> holdings were produced in parallel with thisreport. It is strongly recommended that these plans beimplemented as they support the wider biodiversity<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 116

Glossary6Alluvial sediment – particles derived from river-bornesourcesBasic soils – alkaline soils, soils with pH greaterthan 7.Benthic - in or on the sea bed<strong>Biodiversity</strong> Action Plan (BAP) – <strong>The</strong> UK BAP isthe Government’s response to the Convention onBiological Diversity signed in 1992. It describes theUK’s biological resources and commits a detailed planfor their protection. It is made up <strong>of</strong> Species ActionPlans, Habitat Action Plans and Local <strong>Biodiversity</strong>Action Plans with targeted actions.Biotope - an area <strong>of</strong> uniform environmental conditionsproviding a living place for a specific assemblage <strong>of</strong>plants and animals.Circa-littoral – 40-65m depth zoneDemersal – the area just above the sea bedDiadromous – fish which spend part <strong>of</strong> their lifecyclein freshwater and part in the seaDraw down zone – the area on the margins <strong>of</strong> a pondor lake which become exposed to air when waterlevels drop.Ecological niches - an area or position in theenvironment that tends to suit a species long termsurvival and welfare,Epiphyte – a plant which grows on another species <strong>of</strong>plant or animal.Infauna – Organisms living within the sediment or seabed.Interstitial – the spaces between things, such as sandgrainsIntertidal – the area between high tide and low tidewhich is covered at high water and exposed at lowwaterLittoral – <strong>of</strong> or on the shoreLusitanian species – species whose geographicalrange includes the Iberian Peninsula, particularlythose with a stronghold in that area.Mei<strong>of</strong>auna – animals <strong>of</strong> microscopic size living insediments, marine mei<strong>of</strong>auna is found from the shoreto the deep sea.Mesotrophic – an environment such as a body<strong>of</strong> water with intermediate levels <strong>of</strong> productivity(between oligotrophic and eutrophic).NS (Nationally Scarce) – a species recorded from 16 to100 10 km squares <strong>of</strong> the British National Grid.Oligotrophic – an environment that <strong>of</strong>fers little tosustain life, such as a body <strong>of</strong> water with low nutrientlevels.Pelagic – associated with the open seaPlankton – small, free floating organisms <strong>of</strong> the sea orother aquatic environmentClose up <strong>of</strong> sea urchin spines and tube feet. Photo: Malcolm Nimmo<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 117

Ram – also called head or rab, cement-like materialformed by breakdown <strong>of</strong> granite fragments shatteredby glaciation.RDB (Red Data Book) – RDBs contain lists <strong>of</strong> specieswhose continued existence is threatened in some waySeasearch – Volunteer diver surveys collecting data onmarine species and habitats, organised and managedby the Marine Conservation Society.Sublittoral – Lying between the low tide line and theedge <strong>of</strong> the continental shelfSubtidal – below the level <strong>of</strong> the lowest tideTerricolous – living on or in the groundAcronymsAoNB –BAP –BSBI –CISFBR –CWT –DEFRA –NANS –NR –NVC –IoSWT –IoS –RDB –SAC –SSSI –Area <strong>of</strong> Outstanding Natural Beauty<strong>Biodiversity</strong> Action PlanBotanical Society <strong>of</strong> the British <strong>Isles</strong><strong>Cornwall</strong> and <strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> Federation<strong>of</strong> Biological Recorders<strong>Cornwall</strong> <strong>Wildlife</strong> <strong>Trust</strong>Department for Environment, Food andRural AffairsNatural EnglandNationally ScarceNationally RareNational Vegetation Classification<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> <strong>Wildlife</strong> <strong>Trust</strong><strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong>Red data bookSpecial Area <strong>of</strong> ConservationSite <strong>of</strong> Special Scientific InterestGugh. Photo: Rosemary Parslow<strong>Isles</strong> <strong>of</strong> <strong>Scilly</strong> biodiversity audit Page 118

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