The Isles of Scilly Biodiversity Audit 2008 - Cornwall Wildlife Trust

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The Isles of Scilly Biodiversity Audit 2008 - Cornwall Wildlife Trust

The Isles of ScillyBiodiversity Audit 2008EnvironmentalRecords Centre forCornwall and theIsles of Scilly


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


ContentsForeword Page 5Acknowledgements Page 6Executive Summary Page 71 Introduction Page 91.1 Objectives of IoS Biodiversity Audit Page 91.2 Origins of IoS Biodiversity Audit Page 91.3 What is biodiversity? Page 101.4 The Isles of Scilly Page 101.5 The marine environment of the IoS Page 102. Isles of Scilly Biodiversity Page 112.1 Biological Records and Sources of Information Page 112.2 Summary Statements: Status and Trends Page 122.2.1 Species Page 132.2.1.1 Marine algae Page 132.2.1.2 Charophytes - stoneworts Page 112.2.1.3 Fungi - mushrooms and toadstools Page 152.2.1.4 Lichens Page 162.2.1.5 Bryophytes -mosses and liverworts Page 172.2.1.6 Horsetails, ferns and flowering plants Page 182.2.1.7 Porifera - sponges Page 192.2.1.8 Cnidaria – sea anemones, jellyfish, corals and relatives Page 202.2.1.9 Marine Annelida – worms Page 222.2.1.10 Arachnida - spiders and relatives Page 232.2.1.11 Crustacea – crabs, lobsters, shrimps and relatives Page 242.2.1.12 Myriapoda - centipedes and millipedes Page 252.2.1.13 Odonata - dragonflies and damselflies Page 262.2.1.14 Orthoptera - crickets, grasshoppers and relatives Page 272.2.1.15 Hemiptera - bugs Page 282.2.1.16 Lepidoptera - butterflies and moths Page 292.2.1.17 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 35Isles of Scilly biodiversity audit Page


2.2.1.23 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 Isles of Scilly Biodiversity 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 Biodiversity Conservation Page 934.1 Species Page 944.2 Habitats Page 955. Recommendations for Action Page 1156. Glossary Page 1177. Bibliography Page 119Isles of Scilly biodiversity audit Page


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


AcknowledgementsThis report was produced with support from a grant from Defra’s Aggregates LevySustainability Fund.The authors of this document wish to thank the following people for their input and constructive criticismduring the preparation of 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 of SouthamptonCoral Cay ConservationRaymond DennisJoana Doyle – Cornwall Wildlife TrustCraig Dryden – Isles of Scilly Council Planning OfficerDr Paul GaineyFrank GloysteinLouise Graham – Isles of Scilly AONBMark and Susie Groves – Island Sea SafarisRen HathwayDouglas Herdson - National Marine AquariumAlfred Hicks – of the boat SeaquestDr Keith Hiscock – Marine Biological AssociationJan Loveridge - CWT Marine Strandings NetworkProfessor Christine Maggs – Queens University, BelfastAmanda Martin – Isles of Scilly MuseumDave Mawer, Senior Conservation Warden Isles of Scilly Wildlife TrustCyril Nicholas – Natural England, Isles of ScillyDr Malcolm NimmoJoe Pender – of 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 – Isles of Scilly Sea Fisheries Committee, IoS CouncilChris Wood - SeasearchIsles of Scilly biodiversity audit Page


ExecutiveSummary1 IntroductionObjectives of The Isles of Scilly Biodiversity AuditThis publication represents the key first step in theprocess of producing Biodiversity Action Plansprocess for the variety of both species and habitatsthat make up the unique character of the islands. Theobjectives of this Biodiversity Audit are:· To assess the status and trends in biodiversity inthe Isles of Scilly· To identify the main issues affecting biodiversity· To establish priorities for the conservation ofbiodiversity· To make recommendations for immediateaction to conserve and enhance the Isles of Scilly’sbiodiversity2 The Isles of Scilly’s BiodiversityAnalysis of 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 Isles of Scilly· Conservation Importance· Trends and Issues affecting that species group orhabitat type.Overall TrendsThe extent and quality of the Isles of Scilly’sbiodiversity have been identified through this initialaudit and, in particular, the baseline for futurereporting of those issues identified and any changeis now in place. Both habitats and species are underthreat from climate change, habitat and environmentaldegradation.The trends are by no means all negative. The growthin public awareness of the unique habitats the islandshave to offer has been very noticeable and the tourismindustry has worked hard to “sell” the environmentalbenefits to the visiting public. The development of theIsles of Scilly Wildlife Trust 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 of the recommendations in this report look tofurther strengthen that relationshipOverall trends of both key species and habitats whereknown are recorded at Section 4 - Isles of Scillypriority tables3 Issues Affecting The Isles of Scilly’sBiodiversityA number of issues that are deemed to have, orpotentially have, an effect on the biodiversity of theIsles of Scilly are discussed at Section 3 of this report.The topics covered are:3.1 Nature Conservation3.2 Agriculture3.3 FisheriesWild flowers in arable fields. Photo: Rosemary ParslowIsles of Scilly 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 overviewof the causes, or potential causes, of change tothe biodiversity of the Isles of Scilly and will helpstimulate debate during the production of any actionand implementation plans or programmes of work forboth priority habitats and species.4 Priorities for Biodiversity ConservationThe diversity of the Isles of Scilly’s habitats andspecies groups is an important contributing factorof 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 of the islands’ biodiversity and toensure the best use of 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 Isles of Scilly have asignificant percentage of the UK population.Priorities for biodiversity conservation include:· 293 Species· 18 HabitatsSome of 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 of that future research.5 Recommendations for ActionA number of key recommendations are provided,with further explanation at Section 5. They needto be addressed as a matter of priority and theirimplementation will go a significant way towardsthe promotion and furtherance of biodiversityconservation in the Isles of Scilly.Recommendation 1 – SurveyPromote and instigate survey work for those speciesand habitats on the Isles of Scilly 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 ofspecies and habitats on the Isles of Scilly priority list.Recommendation 3 – Manage IoSWT land holdingsImplement, maintain and monitor the work plansoutlined in the Management Plans for Isles of ScillyWildlife Trust holdings produced in conjunction withthis report.Recommendation 4 – Marine Protected AreaWork towards the inclusion of the Isles of Scilly 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 theIsles of Scilly as a focus for delivering biodiversityaction on Scilly.Spiny starfish Marthasterias glacialis amongst anemones. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page


1Introduction1.1 Objectives of Isles of Scilly’s Biodiversity AuditThe Isles of Scilly’s Biodiversity Audit is the firstimportant step in identifying the process of preservingthe variety of habitats and species that make up theunique character of the islands, both for now and thefuture.The objectives of this document are:· To assess the status and trends in biodiversity inthe Isles of ScillyThere are good sources of information available forthe Isles of Scilly, in particular the Red Data Bookfor Cornwall and the Isles of Scilly (published in1997 and due for re-issue in 2008), the annual Islesof Scilly Review and the recently published NewNaturalist edition of The Isles of Scilly by RosemaryParslow. Discussion with experts and conservationorganisations has been crucial in drawing togetherinformation for this Biodiversity Audit. Additionally,there are the numerous recording groups andindividuals who diligently record; many are membersof the influential Cornwall and Isles of ScillyFederation of Biological Recorders (CISFBR).All of these sources have been used in combinationwith information published nationally, includingaction plans and regionally in The Biodiversity of theSouth West, to provide an up to date picture of thecurrent status of 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 Isles of Scilly,and how those issues influence habitats and species.· To establish priorities for the conservation ofbiodiversityUsing the wide range of information available,priorities have been established for the conservation ofhabitats and species of the Isles of Scilly.· To make recommendations for action to conserveand enhance the Isles of Scilly’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. Theserecommendations will provide the starting point forthe next stage in the Biodiversity Action Planningprocess which should be the formation of workinggroups aimed at taking each recommendationforward. Implementation can be achieved througha variety of processes including precisely targetedaction plans, broader generic actions or the inclusionof biodiversity priorities in existing or plannedprogrammes of work.1.2 Origins of the Isles of Scilly Biodiversity AuditThe Isles of Scilly Biodiversity Audit 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 Biodiversity Action Plan in1994 and Biodiversity: The UK Steering Group Reportin 1995.The South West Regional Biodiversity AuditDirectly resulting from the UK legislation, the SouthWest formed the first regional initiative and theproduction of the South West Regional BiodiversityAudit in February 1996. It described the key speciesand habitats to be found in the region and had backingfrom the seven Wildlife Trusts, RSPB, English Nature(now Natural England), the Environment Agency andSeaweeds in the intertidal zone. Photo: Angela GallIsles of Scilly biodiversity audit Page


the South West Regional Planning Conference.Based on this cooperation, each county has developedits individual biodiversity audit with Cornwallpublishing theirs in 1997.The Isles of Scilly Biodiversity AuditIt had become apparent that the Isles of Scilly had beenleft behind in the audit process. Despite having highbiodiversity that embraced a unique set of species,there were never enough resources to carry out thebasic research. The development of the Isles of ScillyWildlife Trust (IoSWT) and the production of the Islesof Scilly 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 Cornwall Wildlife Trust 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 Biodiversity?Biodiversity describes the “variety of life”. Species andhabitats are lost and new ones develop through theprocess of evolution. The present rate of change, thethreat of climate change and the impact of humans hasmeant evolution requires direct intervention; we needto manage biodiversity in a sustainable way.Article 2 of the Biodiversity Convention definesbiodiversity as:“The variability among living organisms from allsources including, amongst others, terrestrial, marineand other aquatic ecosystems and the ecologicalcomplexes of which they are part; this includesdiversity within species, between species and ofecosystems.”Put more simply this means the “variety of life”encompassing all the species and their multitude ofdifferent habitats.EvolutionBiodiversity 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 of the 21st century.However, as our environment alters, new habitatsevolve and existing species adapt to survive. Theycreate 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.ExtinctionThe world is losing species and habitat at anaccelerated rate as a result of human activity.Although species evolve to survive in changingenvironments, if the rate of change is too fast thenthey will not adapt quickly enough to maintain theircompetitive advantages.In the UK, populations of many species are decliningat an alarming rate; this has resulted in a majoroverhaul of the Biodiversity Action Plan (BAP) priorityspecies in 2007 with nearly six hundred more speciesbeing added to the list.Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 10


2Isles of ScillyBiodiversityThe biodiversity of the Isles of Scilly reflects theirunique position at the extreme south west of theUnited Kingdom and the associated maritimeinfluences. Situated within the Gulf Stream, the Islesof Scilly have a climate allowing a breadth of 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 of sub-species.2.1 Biological Records and Sources of InformationThe Environmental Records Centre for Cornwall andthe Isles of Scilly (ERCCIS) holds an extensive numberof environmental and geological records for bothmainland Cornwall and the Isles of Scilly. Historically,species information has been collected by dedicatedindividuals or recording groups. Unlike Cornwall,there has been little habitat mapping, but recent workto create management plans for all Isles of ScillyWildlife Trust land holdings has made significantstrides in rectifying this for the terrestrial environment.The species records and recent habitat mapping,coupled with invaluable contributions from NaturalEngland, Isles of Scilly Council and the Duchy ofCornwall, have allowed an assessment of the statusand trends of biodiversity on the Isles of Scilly,relating to habitats and species.The United Kingdom is considered one of the mostcomprehensively studied regions in the world interms of species present and habitat cover. Despitethis there are still significant gaps in the knowledgebase; there is still uncertainty as to the number ofspecies present, their population sizes and the levelsof decline each species can tolerate. Additionally,there is considerable imbalance to that knowledgebase; there is comprehensive data with respect toflowering plants, mammals, birds and the higherlevels of invertebrates (butterflies and moths). Theless 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 of speciesnumbers these groups contribute more to overallbiodiversity, and knowledge of where they sit in thewider picture is fundamental to the conservation of thehigher forms of species.Species ExpertsThere already exists a wide understanding of thewildlife of the Isles of Scilly through the dedicated workof both recording groups and individuals. Particularstrengths are birds (Isles of Scilly Bird Group), bats(Isles of Scilly Bat Group) and higher plants (CISFBR).Many of the groups and individuals contributed tothe Red Data Book for Cornwall and the Isles of Scillyin 1997 and are updating that publication for re-issuein 2008. All these groups and individuals have beenconsulted during the publication of this audit.Habitat MappingUnlike their close neighbour Cornwall, the Isles ofScilly have not benefited from a systematic terrestrialhabitat mapping project. The production of theoriginal management plans for IoSWT land had somehabitat maps, but these plans did not contain detailfor other land holdings, particularly that held by theDuchy of Cornwall and Tresco, privately owned bythe Dorien-Smith family.As a condition of the ALSF grant a repeat of themapping of all the IoSWT land holdings wasagreed. This was a key part of the updating of theJewel anemone. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 11


management plans for these holdings. Whilst thismapping will cover 40% of the islands above the MeanHigh Water Level, there are still important areas thatremain outside of this work, particularly intertidalareas.Part of one of the main recommendations of this auditis for systematic habitat mapping of the Isles of Scilly;without this there are elements of a biodiversity auditthat remain inconclusive.Environmental Records Centre for Cornwall and theIsles of Scilly (ERCCIS)The Environmental Records Centre for Cornwalland the Isles of Scilly (ERCCIS) is the focus for allbiological and geological records for the islands. Therehas been a significant effort to capture all the availabledata for all species to inform this audit. The RecordsCentre is the focus for the re-issue of the Red DataBook for Cornwall and the Isles of Scilly and has adedicated staff responsible for the collection, collationand dissemination of environmental data for the area.Information sources used in the production of thisBiodiversity AuditData and information form a key element of theBiodiversity Action Planning process. The data neededto compile this Biodiversity Audit have come from awide range of sources:· ERCCIS· Local recorders and recording groups· Statutory and voluntary agencies· Isles of Scilly Wildlife Trust· Scientists / species experts2.2 Summary Statements: Status and Trends2.2.1 SpeciesThe following species overviews provide a summaryof the status of the different taxonomic groupsoccurring on the Isles of Scilly.Overviews include:· An introduction to the species group· An indication of the conservation importance ofthe species group· The main trends and issues relating to the groupin the Isles of ScillyThe groupings are broken down by taxonomic groupas follows:2.2.1.1 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 2.2.1.26 Invertebrates (including Insects)2.2.1.27 Amphibians2.2.1.28 Fish2.2.1.29 and 2.2.1.30 Reptiles2.2.1.31 Birds2.2.1.32 and 2.2.1.33 MammalsThe species overviews act as a baseline for furtherwork, in particular the production of individualspecies action plans and will be instrumental ininforming the wider landscape management of keyhabitats.Rocks off White Island. Photo: Angela GallIsles of Scilly biodiversity audit Page 12


2.2.1.1 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 of lightthat is able to penetrate the water. In the clear watersof Scilly, where light penetration is very good,macroalgae is found down to depths of 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 of light so occur at the deepest depths.In Scilly 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 of Scilly. Some speciesare annual, growing and then dying back each year.Large amounts of dead algae are washed up onbeaches around the islands, particularly after storms.These piles of decaying organic material supportcommunities of decomposers and supply nutrients tobeach dwelling organisms.The most diverse group of algae is the red algae whichincludes calcareous species that encrust many of therock surfaces. Approximately 400 species of red algaeoccur in Cornwall, most of which are present in Scilly(Parslow, 2007). The algal communities of Scilly havebeen noted for their high diversity and the presence ofmany rare species (Barne et al, 1996).Important AreasSeaweeds occur on all rocky shores around Scillyand 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 often welldeveloped Alaria esculenta (Harvey 1969). There aredense stands of Laminaria ochroleuca, a rare southwestspecies (Warwick et al, 2003).The kelps provide a three dimensional habitat forother species such as wrasse and urchins. Theysupport epiphytic and epizootic species such asbryozoans and grazers such as blue rayed limpetsHelcion pellucidum. The calcareous pink seaweedCorallina officinalis is abundant between mid tide andlow water, supporting a diverse faunal communityincluding isopods.Conservation ImportanceThe marine algal communities of Scilly are importantbecause of their high species diversity (Barne etal, 1996). Scilly has recently been nominated as anImportant Plant Area for marine algae (Brodie etal, 2007). There are two BAP species and a numberof 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. The JointNature Conservation Committee identified Schmitziahiscockiana as an important species in a review of thearea (Barne et al, 1996). It is at the extreme southernend of its range in Scilly 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 Scilly which is internationally threatenedand rare. It has a very small known distribution,from Brittany in France, to western Scotland andis associated with beds of 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 Scilly(and at one site in the west of Ireland). Myriogrammeminuta is also only commonly found in Scilly.Other nationally rare red seaweeds in the Isles of ScillyareAtractophora hypnoidesCryptonemia lomationGigartina pistillataHalymenia latifoliaPterosiphonia pennataRhodophysema georgei (which lives on Zostera)Rhodymenia delicatulaSchmitzia neapolitanaNationally Gelidium sesquipedale (synonym G. corneum)is only frequent in Scilly and is a southern speciescommon in Iberia. Pterosiphonia pennata and Gracilariabursa-pastoris likewise are southern species of redseaweed which are found there (Brodie et al, 2007).Cryptonemia lomation is extremely rare in the UK, andprobably confined to Scilly (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.Isles of Scilly biodiversity audit Page 13


Trends and IssuesHabitat LossLoss of seagrass in the past represents habitat loss formany species of 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 Scilly butshould be monitored.Invasive SpeciesThe invasive brown macroalgae, japweed Sargassummuticum was first recorded in Scilly in 1991 (Fowler,1992) and now has a firm foothold in the environment(Cook et al, 2001).Pikea californica is a non-native species of red seaweedwhich was first recorded in Scilly in 1983 (Hiscock,1983) and is widespread throughout the surge zonein Scilly (Maggs and Guiry, 1986). It was thought tohave been introduced during World War II on boatsfrom its native East coast of North America. Scilly isthe only area in the UK where this species is recorded.Asparagopsis armata is another alien red alga present inScilly which originates from Australia (Horridge, 1951).Thongweed Himanthalia elongata and other algae. Photo: Angela GallIsles of Scilly biodiversity audit Page 14


2.2.1.2 Charophytes - StonewortsOverviewStoneworts are a small group of terrestrial orfreshwater simple, green algae, of the familyCharophyta. They inhabit aquatic habitats, such asfresh and brackish pools and wetlands. Stonewortshave a requirement for calcium carbonate whichaccumulates on the surface of 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 of these species are foundon the coastal sand dunes and in pools situated onbasic soils.Important AreasThe only site in the Isles of Scilly where stonewortshave been recorded is the Abbey Pool on Tresco. Thereis some confusion as to which species was recorded.Further investigation is needed.Conservation ImportanceThere are no species of particular conservationimportance recorded in the Isles of Scilly.Trends and IssuesResearchMore research is required in order to fully establishwhether there are any species of stoneworts in the Islesof Scilly. 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. There is a range of fungi, butthe more familiar mushrooms and toadstools. can stillgrow in a number of forms – as a mat of 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 toflowering plants. Therefore, if areas are managed wellfor plants involving grazing, and lack of fertilisers,fungal diversity will also tend to be maintained.Important AreasThere are no areas known to be of particularimportance for fungi in the Isles of Scilly, butthat does not mean that there are none. Species ofnational conservation importance are present inScilly and the significance of their locations needs tobe considered.Conservation ImportanceThere are two species on the BAP priority list:Elegant Earthstar Geastrum elegansCoral Tooth Hericium coralloidesTrends and IssuesResearchIt would be useful if an expert review of themushrooms and toadstools of the Isles of Scilly werecarried out. This is a group that is only moderatelywell understood on the mainland of Cornwall andthere appears to have been very little fieldwork carriedout in the Isles of Scilly.Isles of Scilly biodiversity audit Page 15


2.2.1.4 LichensOverviewLichens are lower plants formed from associations ofcertain fungal species with a green alga or bacterium.Lichens may be encrusting, leafy or even shrubby,depending on the species. They vary widely incolouration including shades of orange, green, greyand black.The Isles of Scilly 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 of significant conservation concern are foundon all the main islands. The majority are coastal sites,including heathland and maritime grassland sitesand their associated rocky habitats. Some lichens areassociated with a few individual trees.Conservation ImportanceThere are 8 species on the BAP priority list:Acarospora subrufulaBacidia incomptaCryptolechia carneoluteaHeterodermia leucomela Ciliate strap-lichenOpegrapha prosodeaPseudocyphellaria aurataTeloschistes flavicans Golden Hair-lichenWadeana dendrographaThere are also nine RDB lichens:Bacidia assulataBuellia abstractaCatillaria subviridisHeterodermia propagulifera Coralloid Rosette-lichenLecanora strobilinaLecidia sarcogynoidesLecidella viridansRamalina chondrinaUsnea subscabrosaThere are 4 near threatened species and 16 nationallyscarce species.Trends and IssuesResearchThe localities of many of these species are knowndue to research by Bryan Edwards and others, buta comprehensive survey of 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. The invasion of heathlandby gorse and lack of 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 ParslowIsles of Scilly biodiversity audit Page 16


2.2.1.5 Bryophytes - Mosses andLiverwortsOverviewMosses and liverworts are lower plants, collectivelycalled the bryophytes, many of 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.The Isles of Scilly is small and isolated with limitedgeological variation. Nevertheless, the Isles of Scillyhas a diversity of bryophytes largely attributableto the mild, oceanic climate. Approximately 159species of moss (22% of the total species known in theBritish Isles) and 63 liverworts (again, 22%) have beenrecorded here.Some of the species on the islands are alien speciesthat have arrived with introduced plants. A number ofthe RDB species fall into this category.Important AreasBryophytes are found in a wide range of habitats in theIsles of Scilly from the maritime coasts and heathlands,through the arable land to individual trees in parksand gardens.Conservation ImportanceThere are two species on the BAP priority list:Sphaerocarpos texanusTortula wilsoniiTexas balloonwortWilson`s pottiaWilson’s pottia has not been recorded for over half acentury.There are a further 11 RDB species, 4 of which havebeen introduced. There are further 22 Nationallyscarce species.The 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 LossThe 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 of certain species.TourismIncreased visitor numbers have led to more tramplingof 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 of the nativebryophytes.Isles of Scilly biodiversity audit Page 17


2.2.1.6 Horsetails, ferns andflowering plantsOverviewThe Isles of Scilly have a rich flora of ferns andflowering plants (which include herbs, shrubs, trees,grasses, sedges and their relatives). Only one speciesof horsetail, Equisetum arvense is found in Scilly, andthat only rarely. Plants are found in a wide range ofhabitats ranging from inland grasslands, wetlandsand coastal habitats to those of very exposed cliffs androcky islets. A number of species found in Scilly haveMediterranean and Lusitanian associations and are atthe northern limit of their distribution. Some speciesof plants are unique to Scilly and others, common insimilar habitats in Cornwall, are absent.Important AreasSome sites in the Isles of Scilly are exceptionallyrich in ferns and flowering plants. These includeheathlands on Wingletang, Salakee and PorthellickDowns, dune grassland, the saline pool on Bryherand the uninhabited islands of Samson, Annet, GreatGanilly and Teän. The coastal habitats are particularlyimportant on all the islands. Inland the wetlands ofHigher and Lower Moors and the lakes on Tresco areall significant plant habitats.Conservation ImportanceShore dock Rumex rupestris is listed on Annex II of theEU Habitats Directive.The presence of shore dock is one of the reasons forSAC designation of the Isles of Scilly. The shore dockappears to be in decline and is now only known fromsites on four islands in Scilly.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 of habitat especially of unimprovedgrassland, wetlands, and coastal habitats has animpact on the biodiversity of the higher plantcommunities. Although the areas may be quite small,in the context of the limited land area on the inhabitedislands, the draining of any wetland or spraying of afew hectares of coastal grassland for example can havea deleterious effect.ManagementLack of 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 of species-rich communities of 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 of plant species. Higher and LowerMoors are much drier than they used to be. A smallarea of acid bog has disappeared and with it the bogcotton Eriophorum angustifolium and other unusualplants. Cornish moneywort Sibthorpia europaea has alsogone from all but one of its former sites.PollutionUse of fertilisers and herbicides can all be detrimentalto native plant communities.CollectionOne rare fern has been collected in the past. There areat least two fern species in Scilly that may be attractiveto collectors.MonitoringBSBI recorder, Rosemary Parslow monitors the flora ofScilly 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 Isles of Scilly are leastadderstongue fern Ophioglossum lusitanicum, orangebirdsfoot Ornithopus pinnatus, dwarf pansy Violakitabeliana.Species endemic to Scilly and Cornwall includewestern fumitory Fumaria occidentale and Babington’sleek Allium ampeloprasum var babingtonii.Dwarf pansy Viola kitabeliana is endemic to the Isles of Scilly.Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 18


2.2.1.7 Porifera - spongesOverviewSponges are the least complex of all multicellularanimals; these simple colonial animals vary in formand colour. They are sessile suspension feeders withspecialised cells called choanocytes which drive waterthrough their canals and chambers. They filter largevolumes of water, removing oxygen, fine particles andplankton.Species identification can be difficult and is often onlypossible by microscopic examination of spicules (smallpieces of silica or calcium carbonate which reinforcethe sponges’ structure). Sponges can be found fromthe intertidal zone to deep water habitats. They growon a range of substrates including rocks, shells andseaweeds. Their form may be erect, encrusting orirregular in shape but they are characterised by thepresence of many small water intake holes and fewlarger water outlet holes.Important AreasMany of the rocky reefs in Scilly support rich spongecommunities. Sponges also inhabit the underside ofboulders on the less exposed rocky shores. The circalittoralsponge communities on the sheltered coast ofSt Mary’s, for example are of very high interest andextremely diverse (Fowler and Pilley, 1992)Conservation ImportanceScilly is particularly rich in sponge life (Parslow, 2007),especially on the circa-littoral bedrock (40-65m depth)where there are very high densities of infrequentlyrecorded erect sponges (Munro and Nunney, 1998).this is also a southern species and is nationally scarce.Tethyspira spinosa, a nationally scarce species typicalof exposed sites has been recorded as present in Scillyand, along with Axinella damicornis, has been identifiedin the Natural Area Profile (Natural England) as apriority species for conservation. The nationally scarcespecies Homaxinella subdola and Crella rosea are presentin the Isles of Scilly (Ulster Museum, 2007).Trends and IssuesResearchSponges are recorded during annual Seasearchexpeditions to the Isles of Scilly, however due to thedifficulties of identification in the field not all spongesare recorded at species level.Specimens of many sponges from Scilly have beenadded to the Ulster Museum’s sponge collectionrecently, following survey work by Bernard Picton.DiseaseAlthough there are no reports of sponge disease in theIsles of Scilly, 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 of the sponges in Scilly are BAPspecies the area is rich in sponge life are classifiedunder the BAP habitats ‘fragile sponge and anthozoancommunities on subtidal rock habitats’ and ‘intertidalboulders’. There are several nationally rare and scarcespecies present but it is the diversity and richnessof the sponge communities which is of greatestconservation importance in the Isles of Scilly.Munro and Nunney (1998) found Axinellainfundibuliformis a nationally rare species living incircalittoral areas on western shores in Scilly. 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.).The nationally rare sponge Desmacidon fruticosuminhabits the same type of surfaces and prefers oceanicwater below depths of about 25m.Seasearch surveys during 2007 found Adreusfascicularis at Peter’s Rock and North Chapel Rock;A yellow branching sponge. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 19


2.2.1.8 Cnidaria - sea anemones,jellyfish, corals and relativesOverviewThis group of predominantly soft bodied, simpleanimals is characterised by the presence of stingingcells or nematocysts. They use these nematocystsand their tentacles to catch prey from the watercolumn. Sea anemones, jellyfish, hydroids, sea pensand corals are all members of 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 of substrates including rock, seaweed, shells,wreckage and in soft sediments. Members of thisgroup are important to the recreational dive industryas they are some of the most colourful and attractivecomponents of the underwater landscape. Hydroidsare feathery, fairly inconspicuous members of thisgroup which often 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 of a burrowing fauna (Harvey, 1969)but on the sand flats burrowing anemones may occurwhere sediment is stable. Sea pens also grow in softsediment. Planktonic cnidarians such as jellyfish maybe encountered anywhere in the waters around Scillyand 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 inScilly. 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 ImportanceThe Anthozoa (corals and anemones) are part ofthe BAP habitat ‘fragile sponge and Anthozoancommunities on subtidal rock habitats’.The 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 Scilly (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 of the Wildlife and Countryside Act 1981.Due to their branching structure sea fans are thoughtto provide important attachment sites for the egg casesof some elasmobranchs.Pink sea fans occur in forests in Scilly although theseare not as dense as those around mainland Cornwall,possibly because the exposure is greater in Scilly(Seasearch, 2004). Colonies are also generally smallcompared to mainland sea fans. In Scilly the whitecolour morph is predominant, unlike Cornwall wherepink individuals are much more common. The whitecolour morph occurs in other areas such as Gibraltarand the west coast of Ireland. Populations of 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). The sunset cup coralpopulations in southwest England are at the northernlimit of their distribution and are thought to be a relicof a former, more extensive distribution approximately700 years ago (Jones et al n.d.). The Isles of Scilly isone of only four areas it is known to occur in the UK(Seasearch, 2007).Three species of BAP stalked jellyfish occur in Scilly;Haliclystus auricular, Lucernariopsis campanulata andLucernariopsis cruxmelitensis. These small cnidariansare usually fixed to algae or seagrass by their stalk andmay have suffered from habitat loss when the seagrassIsles of Scilly biodiversity audit Page 20


die-off occurred. The timid burrowing anemoneEdwardsia timida, another BAP species, may have alsodeclined for this reason because it requires stablesediment in which to burrow. The only records of thisspecies are from the 1980s and it is not known whetherit still occurs in the Isles of Scilly.A number of nationally rare and scarce cnidarians arefound in Scilly, 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 soft coral Alcyonium hibernicum, theglaucus pimplet Anthopleura thallia are all nationallyscarce and found in the Isles of Scilly (Barne et al,1996).Some southern species of cnidarian are found in theIsles of Scilly 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 off the southwest of England including Scillyin the autumn of 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 of the Cnidaria and Ctenophora of Scillywas published in the Journal of Natural History in1969 as part of the series of papers on the marine life ofScilly (Robins, 1969).The Seasearch pink sea fan survey has been conductedby volunteer divers in Scilly 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 ofsea fan anemones, sea fan nudibranchs, the conditionof 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 often 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. The pink sea-fan is protected underSchedule 5 of the Wildlife and Countryside Act 1981against killing, injuring, taking possession and sale.Climate ChangePlanktonic species like jellyfish are brought to the Islesof Scilly by prevailing currents and winds. Any changein current patterns brought about by climate changemay influence the occurrence of these species in Scilly.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 off in the 1930s (Manuel, 1988). Theeffect of 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 NimmoIsles of Scilly biodiversity audit Page 21


2.2.1.9 Annelida - Marine WormsOverviewMarine worms are a diverse group yet most areroughly similar in appearance and are often hard toidentify without specialist knowledge or laboratoryanalysis. For this reason they are generally underrecordedwith little known about their conservationconcerns.Soft sediments support rich communities of 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 of worm-like creatures which arefound in the marine environment, these are covered inSection 2.2.1.26 on lesser-studied phyla.In the marine environment worms play a criticalrole in breaking down organic matter, aerating andstructuring sediment. They are the main prey of manyspecies of fish and birds.Important AreasThe sediment shores and sand flats in the Isles ofScilly 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 ofsediment are dominated by sand mason worms Laniceconchigela, sedentary filter feeders which live in tubeswhich they creates out of sand grains and mucus. Theimportance of 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 of Arenicola (Bamber et al, 2001).Conservation ImportanceThere are no worms in Scilly which are BAP species.In general worms are a very under-recorded group.In a 1971 expedition to Scilly, Harris found 17 rare ornewly recorded polychaete worm species for Britain,one of which was new to science. They also found 10species of Spirobis (spiral worm) of which 2 were newto science.In a survey of the faunal communities on theundersides of intertidal boulders in Scilly in 1990,Foster-Smith found that spirobid worms were themost important group in terms of abundance. Sabellavariabilis, a small fan worm very rarely recorded inBritain, is abundant in Scilly (English Nature 1994)Trends and IssuesResearchA number of papers on worms and their relatives havebeen published in the series on the marine flora andfauna of the Isles of Scilly in the Journal of NaturalHistory. Harris published an inventory of the marinePolychaetes of the Isles of Scilly in 1972.PollutionSome worms process large amounts of sediment asthey feed and are vulnerable to accumulation of heavymetals or organic compounds in their tissues. Wormscan also assist in the breakdown of pollution. Intertidalspecies are at risk during oil spill incidents.Peacock worm Sabella pavonina. Photo: Angela GallIsles of Scilly biodiversity audit Page 22


2.2.1.10 Arachnida - Spiders andrelativesOverviewSpiders, harvestmen, pseudoscorpions and mitesare collectively known as arachnids. Spidersare ubiquitous in the Isles of Scilly, being foundthroughout the inhabited islands and on some of 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,of which 169 species have been recorded from the Islesof Scilly, can be found in a vast array of habitats, suchas litter and rotting seaweed, but are so inconspicuousmost go unnoticed.Important AreasThere are no areas known to be of particularimportance, though coastal habitats are clearly ofimportance.Conservation ImportanceThere is one species on the BAP priority list:Silky gallows-spider Dipoena inornata, one of whichwas recorded by Bristowe on the dunes of Tresco in1929.There is one RDB species:Clubiona genevensis is an RDB spider of coastalgrassland and heathland habitats. The Provisional Atlasof British Spiders refers to Scilly as one of its very fewBritish sites. Bristowe recorded significant numbersof 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 ButlerIsles of Scilly biodiversity audit Page 23


2.2.1.11 Crustacea – Crabs, lobsters,shrimps and relativesOverviewThe crustaceans are a group of animals with jointedlegs and chitinous exoskeletons which are shedperiodically. The largest order is the Decapoda whichincludes shrimps, crabs and lobsters. There are over2000 species of crustacean in the waters surroundingthe British Isles, 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 Scilly.Some crab species, lobsters and crayfish are caught bypotting in the fishing season. There is a high diversityof isopods in Scilly; they are common under algae andin fresh water seeps on the shore (Parslow, 2007).Important AreasCrustaceans are found in a wide range of habitatssuch as intertidal pools, under boulders and in softsediment. 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 inScilly, unlike on mainland Southwest coasts whereSemibalanus balanoides is often dominant. This isthought to be due to larval supply problems for S.balanoides, which is rare in Scilly (English NatureNatural Area Profile).A rare hermit crab Cestopagarus timidus has beenrecorded in intertidal areas in Scilly (Harvey, 1964),this is a species which typically has a more southerlydistribution. There are also two recent records of rareslipper lobsters Scyllarus arctus another species at thenorthern limit of its range around Scilly (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 Isles of Scillyon 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 Scilly. 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 Isles of Scilly.Trends and IssuesResearchInventories of some crustacean groups have beenpublished in the Journal of Natural History. These arethe Eucarida (Thurston, 1969), Harpacticoid copepods(Wells, 1970), Ostracods (Neale, 1970) and Mysidshrimps (Makings, 1987).Release of captive bred lobstersThe National Lobster Hatchery at Padstow has workedwith members of the Isles of Scilly Sea FisheriesCommittee and local divers to release 500 juvenilelobsters in 2002 and 120 in 2007 in the Isles of Scilly.These 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 inScilly for many years. The 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 GloysteinIsles of Scilly biodiversity audit Page 24


2.2.1.12 Myriapoda - Centipedes andMillipedesOverviewCentipedes and millipedes belong to the classMyriapoda characterised by the number of legs theypossess. Centipedes are carnivores and millipedes eatvegetation, both are important members of the groundflora community, assisting in the breakdown of leaflitter and processing of organic matter.They live in a variety of terrestrial habitats in the Islesof Scilly.Conservation ImportanceThere 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 IssuesResearchThe distribution and population of Nothogeophilus turkishould be established.Important AreasThe type locality for Nothogeophilus turki is Old TownBay, St Mary’s.White-legged snake millipede Tachypodoiulus niger on an apple. Photo: Colin ButlerIsles of Scilly biodiversity audit Page 25


2.2.1.13 Odonata - Dragonflies andDamselfliesOverviewDragonflies and damselflies are members of the insectorder, Odonata, of which there are 41 species whichbreed regularly in the British Isles. They 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 Scilly there are only two common resident species,blue-tailed damselfly Ischnura elegans and commondarter Sympetrum striolatum. Inevitably, there are anumber of migrants that have been recorded fromthe Isles of Scilly, 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 AreasThe Odonata need pools to breed and those poolswhere breeding populations occur are of somesignificance. The larger freshwater bodies on StMary’s and Tresco and St Agnes Big Pool are knownto have breeding populations of Odonata. Sometimessalt water intrusion may render one or other of thefreshwater pools unsuitable; for example, the St AgnesPool can temporarily be too brackish for dragonflies.Conservation ImportanceThere are no species of particular nationalconservation importance recorded in the Isles of Scilly.Trends and IssuesPollutionEutrophication of freshwater pools may affect thebreeding success of some species.Common darter Sympetrum striolatum. Photo: Colin ButlerIsles of Scilly biodiversity audit Page 26


2.2.1.14 Orthoptera - Crickets,Grasshoppers and their relativesOverviewThe crickets and grasshoppers belong to the insectgroup, Orthoptera, together with earwigs andcockroaches. They are generally a well studied,popular group, with about 30 British species.The Isles of Scilly are not particularly noted for theircricket and grasshopper diversity. There are only ninenative species resident in the Isles of Scilly, but two ofthem are nationally scarce.There are also occasional migrant or vagrant speciesrecorded in the Isles of Scilly such as species of locust.In addition, although they are non-native, the stickinsectsof Scilly 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. They have national RDB status.Important AreasNo particular areas have been identified for this group.Conservation ImportanceThere are no species on the BAP priority list that arefound in the Isles of Scilly, 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. The Isles of Scilly is regularly cited as oneof its strongholds.It is generally considered that introduced species, suchas the stick-insects, should not be considered as beingof conservation importance.Trends and IssuesResearchThe Orthopteran fauna is continually changing.Monitoring the status of each species, in particularthose that are nationally scarce, would be useful.Stick insects are non-native but have spread to wild habitats in Scilly. Photo: Colin ButlerIsles of Scilly biodiversity audit Page 27


2.2.1.15 Hemiptera - BugsOverviewBugs are a large group of insects which belong to theorder Hemiptera; there are about 1700 types of bugsin Britain. The bugs are a diverse group of insects,including such well-known animals as shield bugs,water boatmen, greenfly, and whitefly. They areprobably the most diverse insect group in Britain,although only the fifth largest in terms of species. Theynaturally fall into three major types:• Heteroptera – shieldbugs, lacebugs, damselbugs, ground bugs, flowerbugs, etc.• Auchenorrhyncha – froghoppers, leafhoppers,etc.• Sternorrhyncha – greenfly, whitefly, jumpingplant lice, etc.Important AreasThere are no areas known to be of particularimportance, though coastal habitats are clearly ofimportance.Conservation ImportanceThere are no species on the BAP priority list:There are, however, several species of significance,including two Red Data Book species:• Emblethis verbasci is an RDB ground-bug(Lygaeidae) which is widely distributed insandy coastal habitats in Scilly, but whichotherwise has only two British sites. The Reviewof Scarce & Threatened Hemiptera leaves nodoubt that Scilly is its main stronghold.• Piesma quadratum spergulariae (a beet-bug,Piesmatidae) is classed as a ‘Rare (RDB)Endemic’ in the Review of Scarce & ThreatenedHemiptera. It was described as new to sciencefrom Scilly in the 1960s, and has not been foundelsewhere. It seems well established on theislands.• Strongylocoris luridus is a Notable capsidbug (Miridae). The Review of Scarce &Threatened Hemiptera refers to Scilly as one ofits strongholds.• Dicranocephalus agilis is a Notable spurge-bug(Stenocephalidae) for which Scilly has been anoted site for many years.Trends and IssuesResearchThe Isles of Scilly are important for several bugs. Areview of the bugs, including their distribution andecology needs to be written.Green shield bug. Photo: Colin ButlerIsles of Scilly biodiversity audit Page 28


2.2.1.16 Lepidoptera - Butterflies andMothsOverviewButterflies and moths are members of the insect order,Lepidoptera. There are about 56 resident butterfliesand over 2000 moth species in the British Isles. Theirbodies and wings are covered with small scales, oftenbrightly and variously coloured, forming characteristicpatterns.Butterflies are probably amongst the most popularinsects and most readily identified. The mothsare more difficult and include many smaller,inconspicuous specimens, collectively known asmicro-moths.Moths and butterflies are a well studied group in theIsles of Scilly. At least 539 species have been recordedfrom the islands; these include several nationalrarities. However, some of them may only occur dueto migration or vagrancy.Important AreasWhile large numbers of moths of conservationimportance have been recorded on the islands, thereappears to have been no assessment made of thoseareas that are of most importance.Conservation ImportanceThere are 34 species on the BAP priority list, but atleast nine have not been recorded for several decades,or may only occur as vagrants. There 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 morpheusThe CrescentCelaena leucostigmaSmall Square-spotDiarsia rubiSmall PhoenixEcliptopera silaceataThe RusticHoplodrina blandaRosy RusticHydraecia micaceaDot MothMelanchra persicariaeBroom MothMelanchra pisiRosy MinorMesoligia literosaPowdered QuakerOrthosia gracilisMullein WaveScopula marginepunctataWhite ErmineSpilosoma lubricipedaBuff ErmineSpilosoma luteumBlood-veinTimandra comaeThe CinnabarTyria jacobaeaeThe SallowXanthia icteritiaDark-barred Twin-spot Carpet Xanthorhoe ferrugataThere are additional species that are locally important.Of the butterflies, the speckled wood Pararge aegeriainsula that is recorded in the Isles of Scilly is adistinctive endemic subspecies. The 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 Scilly at present,historically its population seems to have fluctuateddramatically. Two other butterfly species also showslight differences, the subspecies of meadow brownManiola jurtina cassiteridium and the island variationsof common blue Polyommatus icarus which werestudied by Ford (1975).There are three moths which are RDB or nationallyscarce:• Thrift clearwing Bembecia muscaeformis is aNotable B species widespread around the coastsof Scilly• 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 Cornwall and Devon.• Yellow V moth Oinophila v-flava is an RDBspecies that in Britain is found in the open only inScilly.Feathered ranunculus Eumichtis lichenea scillonea andshuttle-shaped dart Agrotis puta insula are both mothswith endemic subspecies in the Isles of Scilly.Trends and IssuesResearchMore research is required in order to fully assess thestatus and diversity of the scarce and rare Lepidopterain the Isles of Scilly. It is important that the status ofthe common and the rare biodiversity listed speciesSpeckled wood Pararge aegeria insula on bramble.Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 29


2.2.1.17 Diptera - Two-winged FliesOverviewFlies include the robber, crane, bee, soldier and hoverflies. There are about 6000 species of fly in the BritishIsles, the majority of which are small and poorlyknownand often difficult to identify.Apart from those easily studied species such as thehoverflies, flies have not been particularly well studiedin the Isles of Scilly in the past.Important AreasThere are no areas known to be of particularimportance for two-winged flies.Conservation ImportanceThere are no species on the BAP priority list:Aphrosylus mitis is a Notable dolichopodid or longheadedfly (Dolichopodidae). The Review of the Scarce& Threatened Flies of GB cites Scilly as one of its fewrecent sites.Trends and IssuesResearchThe Dipteran fauna of the Isles of Scilly needs furtherinvestigation.Narcissus fly Merodon equestris is a persistant pest in commercial narcissus crops. Photo: Colin ButlerIsles of Scilly biodiversity audit Page 30


2.2.1.18 Hymenoptera - Wasps andBeesOverviewWasps, bees and bumble bees include the familiaryellow and black striped insects. However, the groupalso includes many lesser known species, some ofwhich 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 Isles of Scilly tend to beparticularly noticeable, inhabiting gardens, heathland,moorland, hedgerows, coastal grassland, cliffs,sand dunes and former mining areas. There are fewnationally important species found in Scilly, but thediversity of wasps and bees is rich.Important AreasSome of the coastal areas of St Agnes are of mostimportance for Bombus muscorum scyllonius, whileparts of St Mary’s appear to be central to the survivalof Bombus jonellus in Scilly.Conservation ImportanceThere is one species on the BAP priority list:Moss carder-bee Bombus muscorum scylloniusTheScilly bee’ is an endemic subspecies of the mosscarder bee, which had greatly declined (due to loss ofcoastal heathland and grassland) since the 1960s, buthas begun to show some signs of recovery in recentyears. Considering the general public familiaritywith bumblebees this could be an important ‘flagshipspecies’ for invertebrate conservation – and the widerissue of restoring coastal heathland/grassland habitatsin the Isles of Scilly.There is one other species of local interest, heathbumblebee Bombus jonellus. This is a nationally localspecies that has declined greatly in the Isles of Scillysince the 1960s, but has shown some signs of recoverymore recently. It is in the Cornwall Red Data Book andis a good indicator of the health of coastal heathlandand grassland habitats.Trends and IssuesResearchThe moss carder-bee Bombus muscorum scylloniusshould be monitored. The heath bumblebee, whichuntil 2004 was in serious difficulties in the Islesof Scilly, should be studied so that the reason forpopulation fluctuations may be understood.The Scilly bee Bombus muscorum scyllonius is an endemic subspecies of the moss carder-bee. Photo: Andrew CooperIsles of Scilly biodiversity audit Page 31


2.2.1.19 Hymenoptera - AntsOverviewAnts are insects which are characterised by their socialbehaviour, forming well organised colonies. Theymostly have biting parts, which in some species releasea defensive chemical.Ants can be found in a variety of habitats includingheathland and various grasslands. In the British Islesthere are nearly 50 ant species regarded as native, ofwhich 14 have been recorded in the Isles of Scilly. 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 of theEastern Isles are important for the colonies of Formicarufibarbis.Conservation ImportanceThere 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 of view, the Isles of Scilly’s most importantinvertebrate rarity. There 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 of the species and further work on theecology of the species is necessary. The Isles of Scillypopulation remains stable while the only otherpopulation in Britain appears to be in terminal decline.The reb-barbed ant Formica rufibarbis is found on St Martin’s and one other site in Britain. Photo: IoSWTIsles of Scilly biodiversity audit Page 32


2.2.1.20 Coleoptera - BeetlesOverviewBeetles are a large group of insects which belong tothe order Coleoptera. The beetles are one of the largestinsect orders, numbering some 3900 species in theBritish Isles. The beetles include such well-knowngroups such as ladybirds and weevils. They arecharacterised by their hard, wing cases, which may becoloured or have a metallic appearance.The beetles of the Isles of Scilly have been relativelywell-recorded, with a species list of 568 species, butsome of the records are rather old.Important AreasThe coastal areas are of importance for several rarebeetles, but the best areas within those coastal areas donot appear to have been described and published.Conservation ImportanceThere is one species on the BAP priority list:Meloe proscarabaeus black oil-beetleThere are 10 RDB species. Of the 10 species listed, themajority are of indeterminate status and the followingfour may be of most significance:Silpha obscura RDBPsylliodes hyoscanii RDBCathormiocerus maritimus RDBCathormiocerus myrmecophilus RDBThe two Cathormiocerus species of weevil may beconsidered locally important for the Isles of Scilly.Both are specialists of grazed sea-cliffs in the southwestand are threatened by cessation of coastal grazingand increased public pressure on cliff-top habitats.There is one further species of significance: Tansy leafbeetleChrysolina graminis. This is a declining specieswith the Isles of Scilly as one of the few places withpost-1980 records. The recent Atlas of the Seed & LeafBeetles of 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 of conservation concern.Habitat LossThe 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 tramplingof certain areas and an increase in uncontrolled fires.Black oil beetle Meloe proscarabaeus. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 33


2.2.1.21 Mollusca – Slugs, snails,bivalves and relatives (marine)OverviewMolluscs are the largest and most diverse group ofmarine animals; they also inhabit freshwater andterrestrial habitats. Most are soft 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 ofall mollusc species in Scilly and concluded that themolluscan fauna of the area was extremely rich. Theylisted over 400 species, representing over half themollusc species recorded for all of North West Europe.7.7% of the molluscs in Scilly are considered southernor Lusitanian species, and over three quarters of thespecies present are also found in the Mediterranean.Some molluscs which are common on the mainlandare much rarer in Scilly, 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 of Scilly and middens of limpetshells have been found there, some dating back to theBronze Age (Parslow, 2007).Important AreasMolluscs have exploited all of the diverse range ofmarine habitats in Scilly, from the tiny lagoon snailsPaludinella littorina (See Section 2.2.1.22) in the sprayzone at the top of the shore to the burrowing razorshells in the sand and limpets on the rocky reefs. Thesandflats support several biotopes including onewhich is dominated by razor shells Ensis spp. whichare burrowing bivalves (Warwick, 2004). The 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 Scilly),Leptochiton scabridus (a nationally scarce chiton).The warty cockle Plagiocardium papillosum is thought tohave disappeared from Scilly (Barne et al, 1996).Lucinella divaricata is a bivalve which burrows in cleansand. In the UK has been found alive only in Scilly andit is a southern species.Trends and IssuesSpecies associated with seagrass, such as the fanmussel Atrina fragilis have declined in Scilly throughhabitat loss.Scallops Pecten maximus are found on sandy and gravelsea beds and are exploited by scallop dredging vesselsoff the coast of the Isles of Scilly.Shell collecting (especially for cowries Trivia arcticaand T. monacha) is popular with tourists in Scilly,though most shells will be empty when taken. If thishas any impact it may be on hermit crabs which woulduse some types of 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 Scilly and was subsequentlyrelocated to the mainland (S.Watt, pers. comm.).Conservation ImportanceThe fan mussel Atrina fragilis is a BAP species whichhas declined in the Isles of Scilly (S. Turk, pers comm.).This large bivalve used to be abundant in the intertidalzone in Scilly but is now rare there.Ostrea edulis, the native oyster is another BAP speciespresent, though rare in Scilly, this is decliningnationally. An attempt was made to introduce thisspecies for cultivation in Scilly but this largely failed(Turk and Seaward, 1997).A number of other molluscs have been recordedin Scilly which are identified as nationally rare orscarce. These include the seaslugs Atagema gibba andDoris sticta (both nationally rare), Trapania pallidaand Tritonia nilsodneri (both nationally scarce);Painted topshell Calliostoma zizyphinum. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 34


2.2.1.22 Mollusca – Slugs, snails,bivalves and relatives (terrestrial andfreshwater)OverviewThe Isles of Scilly is impoverished in terms ofmolluscan species compared to the mainland withsome species which are common on the mainlandbeing completely absent on Scilly, however for thearchipelago’s size the diversity of molluscs is relativelyhigh. Some molluscs show variations from mainlandforms due to their long separation from the mainlandfauna (Turk et al, 2001).There are 70 species of terrestrial and freshwatermollusc recorded on Scilly, over half the UK species.The granitic rocks are an acidic substrate which is lessthan ideal for providing habitat for snails which needcalcium to create their shells.Important AreasThe supralittoral zone or spray zone at the top of theshore is important for many gastropods which areoften found in caves and strandline vegetation.The sand dunes of Scilly are generally graniticnot calcareous like those in Cornwall but thereare areas of shell sand that still support the samespecies assemblage as Cornwall apart from theround–mouthed snail Pomatias elegans which is absentin Scilly. Maritime grassland and heathland areimportant for snails in Scilly.The shortage of freshwater habitats in Scilly meansthat there are few wetland mollusc species. Severalpond snail species and five species of pea mussel arepresent (Turk et al, 2001).St Mary’s has the largest mollusc fauna and supportsnearly all the species recorded in Scilly whereas thesmaller islands have lower species richness (Cameron,2006).Conservation ImportancePaludinella littorina the lagoon snail is protected bythe Wildilife and Countryside Act, 1981. The Isles ofScilly 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 of theSSSIs which are drawn at the high water mark.None of the other terrestrial or freshwater molluscson Scilly are BAP species or species of conservationconcern however they are important prey for birdssuch as the song thrush.Trends and IssuesResearchRichards and Robson (1926) recorded 42 species ofmollusc on Scilly in 1925.Holyoak (2003) found ten mollusc species which werenew to Scilly including local and introduced species.Cameron (2006) recorded 51 species from islands.Introduced speciesA number of snail species have been introduced to theislands. These include the garden snail Cornu aspersumwhich is abundant in dunes and coastal habitatsincluding being widespread on the uninhabited islandof Annet (Holyoak 2003; Parslow, 2007). Introductionsmay have been by human inhabitants or smallerspecies could have arrived attached to birds (Cameron,2006).No exotic species of mollusc have been recordedin Scilly but Holyoak (2003) speculates that theintroduction of exotic plants to Tresco Abbey Gardensmay have led to the introduction of associated molluscspecies yet to be found. There is conjecture that theslug Boettgerilla pallens was introduced in this way(Cameron, 2006).White lipped snail Cepaea hortensis. Photo: Colin ButlerIsles of Scilly biodiversity audit Page 35


2.2.1.23 Bryozoa – Sea MatsOverviewBryozoans are known as sea mats or moss animals andare colonial animals some of which resemble plants.They are groups of tiny zooids which use tentaclesto filter feed on microscopic organisms. Bryozoansmay grow on other species such as kelp, or on rockysurfaces. Some species are soft and gelatinous whileothers such as ross coral Pentapora foliacea are hard andcalcified. They are often overlooked or confused withalgae and are consequently under recorded. They arean important food source for many species of seaslug.There are about 270 species of bryozoan in Britain,most are marine and about 80 are known in Scilly(Hayward, 1971).Important AreasAreas of 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 ImportanceThere are no species of 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).The Joint Nature Conservation Committee identified anumber of scarce and rare marine species for a reviewof Scilly. One of 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 Isles of Scilly (Seasearch, 2007). This maybe partly due to a lack of recording effort at other UKsites.Watersipora complanata is a nationally rare intertidalspecies with a southern distribution found in Scilly(Barne et al, 1996).Trends and IssuesResearchThe bryozoans of the Isles of Scilly have been studiedby Hayward (Hayward 1971 and 1976) and twospecies lists have been published in the Journal ofNatural History.Ross coral Pentapora foliacea and anemones. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 36


2.2.1.24 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. They move slowly, using awater vascular system with hundreds of 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 of echinodermliving within the 200m depth contour (Southward andCampbell, 2006). The Isles of Scilly have been notedfor their echinoderm fauna, with about 50 speciesrecorded there (Rowe, 1972), in particular the prolificburrowing heart urchins.Important AreasThe intertidal sand flats at St Martin’s and throughoutthe archipelago support aggregations of 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 of 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 Isles of Scilly they are common in mostsublittoral areas and the effects of their grazing aremost noticeable in the circalittoral on bedrock andboulders (Hiscock, 1984).Conservation ImportanceNone of the echinoderms present in Scilly are BAPspecies and no rare or scarce species have beenhighlighted as present in Scilly.Trends and IssuesResearchRowe (1971) published a paper on the echinoderms ofScilly in the Journal of Natural History.CollectionEchinus esculentus has been exploited in British waterssince the 1960s for the curio trade (Bishop, 1985).In Scilly it was collected for some years and theimpacts of 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 ofepiphytes in kelp forests (Bishop, 1985). Bishop foundthat the impacts of the fishery were negligible despitethe removal of 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, 2008). They can be threatened by extractionof sand or gravel (Southward and Campbell, 2006).Cotton spinner Holothuria forskali and a starfish Henricia sp. on a rocky reef. Photo: Frank GloysteinIsles of Scilly biodiversity audit Page 37


2.2.1.25 Tunicates – Larvaceans,thaliaceans and ascidiansOverviewTunicata (or Urochordata) is a subphylum of thephylum Chordata which means that these species havea dorsal nerve cord (a notochord), like the vertebrates.Most members of the Tunicata only show thischaracteristic in their larval stages and it disappears inadult stages. There are 60 species of tunicate in Britainand approximately 50 have been recorded aroundCornwall and the Isles of Scilly (Gainey, 1997).Seasquirts are the most noticeable members of theTunicata and are often 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 of the Tunicata. Rowe(1972) studied these groups in the Isles of Scilly andfound one species of Larvacean Oikopleura dioica to bevery common in the plankton at night. The ThaliaceanDoliolum nationalis was also present in the nightplankton and was the only member of the Thaliaceapresent in Scilly.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 Isles of Scilly. They also growon seaweeds and their holdfasts.Conservation ImportanceThe orange lights seasquirt Pycnoclavella aurilucenshas been recorded in the Isles of Scilly 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 of the Enteropneusta(acorn worms), Ascididiacea (seasquirts), Thaliacea(salps), Larvacea (larvaceans) and Cephalochordata ofthe Isles of Scilly in the Journal of Natural History.Lightbulb seasquirts Clavelina lepadiformis. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 38


2.2.1.26 Lesser-studied phylaOverviewThere are a number of marine phyla present in theIsles of Scilly about which less is known due to thelack of recording effort or the difficulties of studyingthem.Single celled organismsSingle celled organisms form the basis of manyfood chains. In the marine environment, planktonicorganisms bloom in late spring as daylight increasesand the water begins to warm. The dominantphytoplankton species in the Celtic Sea are Skeletonemacostatum and Thalassiosira spp. (Edwards and John,1996). The phytoplankton bloom triggers a bloom ofzooplankton 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 Scilly (Harvey, 1969). The Foraminiferaare large for single celled organisms and cansometimes be seen with the naked eye. They weresampled and recorded in Scilly by Atkinson in 1970 aspart of the series in the Journal of Natural History.The continuous plankton recorder (CPR) survey haspassed through the Isles of Scilly every year since 1950,taking an average of 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 GallIsles of Scilly biodiversity audit Page 39


CtenophoraThe Ctenophora or comb jellies, a group of gelatinousplanktonic animals, similar in appearance to jellyfishare present in the waters around the Isles of Scilly.Robins (1969) published a list of the Cnidaria andCtenophora in the Journal of Natural History.Platyhelminthes / Turbellaria (Flatworms)These have flattened bodies and often live as parasites.In 1986 a paper on parasitic Digenea (a type offlatworm) in marine snails was published by Newell.Faubel and Warwick (2005) studied the freelivingflatworms (Turbellaria) of Scilly to produce aninventory. They found 67 species of 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 of marine Nemerteans which had all beencollected from the Isles of Scilly. There are only 2known species of terrestrial ribbon worms in Scilly,both are introduced species. Argonemertes dendyi isfrom Western Australia and Antiponemertes pantini isfrom New Zealand.RotiferaThese ‘wheel animalcules’ are less than 2mm long andhave not been studied in Scilly.Gastrotricha (Hairybacks)Hummon and Warwick (1990) studied the hairy-backs(Gastrotricha) of the Isles of Scilly and listed 31 specieswhere there were previously none recorded, one being‘thus far endemic to Scilly’.Kinorhyncha (Thorn-skins)There are 16 known British species of these interstitialmeiofauna. They have not been studied in the Isles ofScilly.Nematoda (Eel worms)Warwick and Coles produced a checklist of free livingNematoda in Scilly, published in 1977 which detailed103 species, 16 of which were new to Britain and 6were new to science.EntoproctaThese are microscopic animals which may becolonial or solitary and may be associated with otherinvertebrates. Hayward (1971) published a list ofBryozoa and Entoprocta of the Isles of Scilly in theJournal of Natural History.Drift is characterised by Sagitta tasmanica.SipunculaThese are unsegmented worms which have not beenstudied in the Isles of Scilly.EchiuraThese are unsegmented worms which have not beenstudied in the Isles of Scilly.Chelicerata (Sea spiders and marine mites)In 1972, King published a list of Pycnogonids (seaspiders) a group of non-crustacean marine arthropodsof the Isles of Scilly.Brachiopoda (Lamp shells)These are ancient sessile marine animals with dorsaland ventral valves, they have not been studied in theIsles of Scilly.Phoronida (Horeshoe worms)Phoronids or horseshoe worms are another wormlikephylum. Only two species have been recordedin Scilly, Phoronis muelleri and Phoronis pallida (NBNGateway, 2008)Hemichordata (Acorn worms)Rowe (1972) recorded two species of acorn worms(Enteropneusta) in Scilly 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)of the Isles of Scilly. These unusual small animals arecurrently classified in their own phylum (Tardigrada)which is thought to be related to the arthropods.CephalochordataOne species of cephalochordate, a phylum relatedto the tunicata has been recorded in Scilly, this isBranchiostoma lanceolatum. Rowe (1972) published alist of the Enteropneusta (acorn worms), Ascididiacea(seasquirts), Thaliacea (salps), Larvacea (larvaceans)and Cephalochordata of the Isles of Scilly in theJournal of Natural History.Chaetognatha (Arrow worms)These small wormlike species can be used as indicatorspecies and are useful in characterising water masses.The water mass from the south/south west ofScilly is characterised by certain species such as thechaetognath Sagitta serratodentata, the North AtlanticIsles of Scilly biodiversity audit Page 40


2.2.1.27 Amphibia – frogs, toads andnewtsOverviewAmphibians include frogs, toads and newts. The Islesof Scilly seems suitable for the three species that arefound in Cornwall, but only one is certainly foundthere.The common frog Rana temporaria is found on StMary’s and possibly on Tresco, but the commontoad Bufo bufo – if it ever existed in the Isles of Scilly- appears to be extinct and there are no records of anyspecies of newt.the common frog.Conservation ImportanceThere are no species on the BAP priority list that arefound in the Isles of Scilly 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 of 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 of ditch maintenance.Important AreasThe mires and ponds of St Mary’s are important forCommon Frog Rana temporaria. Photo: JB&S BottomleyIsles of Scilly biodiversity audit Page 41


2.2.1.28 Freshwater and Marine FishOverviewFish belong to the phylum Chordata and are dividedinto the Chondrichthyes (cartilaginous fish) andOsteichthyes (bony fish), with members of both groupsfound in the Isles of Scilly. Fish are found throughoutthe marine environment in Scilly including specieswhich live in rockpools on the shore, demersal (bottomdwelling) species and pelagic (open water) fish. As anoceanic archipelago Scilly is important for both coastaland oceanic species. The young of some fish speciesmay be found in rockpools or in the shelter of seagrassbeds which they use as nursery areas. There are moreBAP species of fish in the Isles of Scilly than any othergroup of 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 often seen inlate summer, followed by seabirds (R.Parslow, pers.comm.).Important AreasFish are distributed throughout the waters of the Islesof Scilly from surface waters e.g. sunfish, to deeperbenthic species such as plaice. Seagrass beds are animportant nursery area for juveniles of many fishspecies. Their structural complexity provides shelterand refuge from predation for small fish. They alsosupport populations of 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.There are freshwater fish in some of the pools on Scillyand 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* These are generally deeper water species and maynot occur within the 50m depth contour around theIsles of Scilly.** Though recorded as present, these species areprobably very rare in the waters around Scilly and nottypical of the fish fauna of the area.Basking sharks Cetorhinus maximus, are the largestfish in British waters (up to 12m in length) and arecommonly sighted around Scilly, particularly insummer months. They are plankton feeders and willmove great distances to reach frontal areas where theplankton is rich. They are often seen in associationConservation ImportanceThere are 32 fish species recorded in Scilly which arenational BAP species, of these 12 are elasmobranchs(Sharks, skates and rays) and the rest are bony fish.Three species migrate between freshwater andseawater. There is a grouped species action plan forCommercial Marine Fish which looks at managementof individual stocks. In Scilly stocks of 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 NimmoIsles of Scilly biodiversity audit Page 42


with herring Clupea harengus and mackerel Scomberscombrus which are also plankton feeders (NaturalArea Profile). As well as being BAP species, baskingsharks also receive protection under the Wildlife andCountryside Act, 1981.Blue sharks Prionace glauca are a south-west UKspecies for part of 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 (2008) been given protectionunder Schedule 5 of the Wildlife and Countryside Act1981.Mackerel is one of the most abundant pelagic speciesoff the west coast of Britain; it is common in the Isles ofScilly and is protected under a grouped species BAP.Mackerel spawn along the edge of the continental shelfand west of 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 Scilly and lesser sandeelAmmodytes marinus is a BAP species (Hiscock, pers.comm.). They are an important food source for manyother fish and seabirds. Their distribution is dependenton the presence of coarse sand in which they burrow(Natural Area profile).Cod Gadus morhua is seasonally abundant in Scillydespite threats in other areas of 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 Profile).Plaice Pleuronectes platessa are the most abundantcommercial flatfish, usually found on sandy substrate.They are long lived and take three years to reachmaturity. Dover sole Solea solea is found off the Islesof Scilly and is caught in trawls. Dover sole spawnaround the Isles of Scilly and juveniles spend up totwo years in inshore waters (Natural Area Profile).Ling Molva molva spawn at the edge of the continentalshelf and use all the waters around Scilly and thesouth-west peninsula as a nursery area (Pawson andRobson, 1996). They are commonly found aroundstony areas, reefs and wrecks and are sometimessighted by divers in Scilly.Short-snouted seahorses Hippocampus hippocampus arethought to breed in the eelgrass beds in Scilly. Theyare on the IUCN Red List of threatened species asVulnerable, they are also an OSPAR priority species(Garrick-Maidment, 2007). Long-snouted seahorsesHippocampus guttulatus may also be present. In 2008both species of seahorse received protection underSchedule 5 of the Wildlife and Countryside Act 1981.This makes it illegal to kill or take them and possessionof a seahorse will also become an offence. Protectionextends to the seahorses’ habitat as it will be illegalto damage or obstruct their place of shelter or evendisturb them in their place of shelter.Salmon, sea trout and European eel are exploiteddiadromous fish which means they spend part of 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 of 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 of thisspecies in 2007. Montague’s blenny Coryphoblenniusgalerita is a common species in higher rockpools inScilly (Parslow, 2007); this is a species with a southerndistribution which reaches its northern limits insouthwest Britain.The grey triggerfish Balistes capriscus is found inScilly and is generally a warmer water species whichhas become better established on the south coast ofBritain 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 of the Isles of Scilly 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 mostof the larger freshwater pools on the islands. Greymullet also get stranded in the pools and gobiesIsles of Scilly biodiversity audit Page 43


Pomatoschistus minutus and P.microps are found insome (Bamber et al, 2001).The giant goby Gobius cobitis is nationally scarce and isa Mediterranean species, at the northern extreme of itsrange. It occurs only in the far south west of England,including a significant population in Scilly (Potts andSwaby, 1995). Giant gobies are listed on Schedule V ofthe Wildlife and Countryside Act 1981, which protectsthem from intentional killing, injuring or taking.Trends and IssuesResearchDr Peter Henderson of the University of Oxford iscurrently compiling a fish species inventory for theJournal of Natural History as part of the All TaxonBiodiversity Inventory.Ren Hathway has been working with DouglasHerdson (National Marine Aquarium) and Dr PaulGainey to update the fish species checklist publishedby the Isles of Scilly museum in 1971.Dr Ken Collins from Southampton University hasbeen carrying out research on the shark populationsof Scilly for the last six years with particular focus onthe Blue Shark. Most of the blue sharks which havebeen tagged have been females and there has been arecapture or tag retrieval rate of approximately tenpercent (J Pender, pers. comm., Whittaker, 2001.).This wide ranging species has been shown to movefrom the east coast of the United States, to Portugaland north to Scilly. They appear in the Isles of Scillybetween 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. There 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 of theirSharkwatch programme. They can migrate overlarge distances to feed at fronts where planktonaccumulates. During winter they have been shown tomove further offshore to the edge of the continentalshelf where they perform daily dives to great depths tofeed (D. Simms, pers. comm.).Climate ChangeCertain fish species may act as climate changeindicators. Atlantic triggerfish have begun to appearfrequently in waters around Scilly 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 of the UK,these range extensions are likely to be noticeable inScilly before other parts of the southwest peninsulaand there are some species that are expected to spreadnorth soon and should possibly be highlighted tofishermen to encourage recording when these speciesappear.FishingSee section 3.3, fishing.There are two trawlers operating from St Marys whichtarget demersal species. These 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.These 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 of Scilly. Blue sharks, for example,are a wide-ranging pelagic species which is heavilyoverfished. They 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 of seagrass is likely to affect the juveniles of 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 NimmoIsles of Scilly biodiversity audit Page 44


2.2.1.29 Terrestrial ReptiliaOverviewThe terrestrial reptiles encompass lizards, slow wormsand snakes. The Isles of Scilly support reptiles both onland and at sea. The only terrestrial reptile is the slowworm Anguis fragilis which is found on Bryher. It isknown to be an introduction.Important AreasThose parts of Bryher, such as land adjacent to GreatPopplestone Bay, are of importance.Conservation ImportanceThere 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 of slow worms on Bryher.ManagementAny hedge management on Bryher should take intoaccount the presence of slow worms.Public AwarenessThe 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: Geoffrey JonesIsles of Scilly biodiversity audit Page 45


2.2.1.30 Marine Reptilia – Sea TurtlesOverviewAll seven species of sea turtle are globally threatenedand most are migratory, often travelling hugedistances across open water. Only female adultsreturn to the land to lay eggs, the rest of their lifecycleis pelagic. Previously, occasional sightings of turtlesaround the coast of Britain were treated as thoughthese were lost individuals which had strayed offcourse. Now, for leatherbacks and possibly loggerheadturtles it is accepted that our waters are an importantpart of their range.Leatherback Dermochelys coriacea, Kemp’s ridleyLepidochelys kempii and loggerhead turtles Carettacaretta have been recorded around Scilly. All marineturtles are on the IUCN red list of threatened species.Important AreasExcept for strandings, sea turtle sightings are generallyoffshore, often in deeper water. Leatherback turtlesfeed in the water column on schools of jellyfish,individuals of this species have been recordedtravelling over 5000 kilometres and they are thoughtto be nomadic rather than migratory. The first knownrecord from Scilly is from 1916 when a leatherbackwas found caught in an antisubmarine net south of theBishop Rock (Penhallurick, 1982)Loggerhead turtles are occasionally seen around Scilly(Penhallurick, 1982).There is one definite record of aKemp’s ridley turtle in the Isles of Scilly from 1925.This is the World’s rarest sea turtle and its range doesnot normally extend this far north.Species of Flora and Fauna (CITES) 1975, AppendixII of the Bern Convention 1979, Appendices I and IIof the Bonn Convention 1979 and Annex IV of theEC Habitats Directive. The loggerhead is also listedas a priority species on Annex II of the EC HabitatsDirective. All sea turtles are protected under Schedule5 of the Wildlife and Countryside Act 1981 and theConservation (Natural Habitats & c.) Regulations 1994.Trends and IssuesResearchThere is a sea turtle research group at ExeterUniversity’s Cornwall Campus although none of theircurrent research is specifically on turtles in Scilly.Strandings and sightings records are collected by SeaQuest South West, the Cornwall 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.The main threat to sea turtles in UK waters is the riskof ingestion of 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 of 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, areoften juveniles which are thought to have strayed offcourse by accident. The possible exception to this isloggerheads which may be at the northern limit oftheir 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 Trust.All sea turtle species are listed on Appendix I of theConvention on the International Trade in EndangeredLeatherback turtles Dermochelys coriacea are occasionally sightedaround the islands. Photo: Mike DainesIsles of Scilly biodiversity audit Page 46


2.2.1.31 BirdsOverviewSeabirdsThe Isles of Scilly’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% of the UKpopulation, 3% of the W Europe/Med/W Africa) andas a Special Protection Area (SPA) in 2001 for theirpopulation of European storm-petrels Hydrobatespelagicus (7% of the European storm-petrels in the UKbreed in Scilly). Other seabirds found here includeroseate tern Sterna dougallii, a very rare breedingspecies in Britain. It was a former breeding species inScilly but has not bred since about 1994 and is nowa scarce summer visitor. Small numbers of commonterns Sterna hirundo breed here, this being an Annex IIspecies on the EU Habitats Directive.Terrestrial birdsThe small size of the Isles of Scilly means that thepopulations of the resident terrestrial birds arenecessarily low, but some of them are at particularlyhigh densities. Species such as the song thrush Turdusphilomelos, a species of conservation importancedue to its significant population declines over thepast century in Britain, are found in relatively largenumbers here.Passage birdsScilly is notable for the number of migratory birds thathave been recorded here. The species list for the Islesof Scilly is one of the highest for any part of Britain.However, many of the birds have only been recordedas rare visitors, including a high proportion whichmay be described as vagrants.Important AreasMany of the islands of the Isles of Scilly 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 of the individualsites, it is critical to recognise the significance of all theseabird breeding sites as a single system.Conservation ImportanceThe Isles of Scilly are internationally important for aseabird assemblage of more than 20 000 birds and inparticular for breeding lesser black-backed gull andEuropean storm-petrelThey are nationally important for European shagPhalacrocorax aristotelis (3% of 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 of Dorset, but they have not bred for over adecade.Balearic shearwater Puffinus mauretanicus, a CriticallyEndangered species, spends some of the year in smallnumbers in the waters of the Isles of Scilly.Atlantic puffins Fratercula arctica, because of theirengaging appearance, are probably the most noticeablebreeding seabird to the general public and could beused as a flagship species. There are very few coloniesin England and the population in Scilly has fallen overthe last century from many thousands to only about ahundred.Song thrushes Turdus philomelos occur at high densities in Scilly and are very tame. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 47


Lesser black-backed gulls Larus fuscus; 4% of the UK population breed in the Isles of Scilly. Photo: Rosemary ParslowThere are 45 species on the BAP priority list, but only12 of those species might be considered to be at alldependent on the Isles of Scilly for their survival andonly seven of them breed there:Herring GullCommon CuckooDunnockSong ThrushCommon StarlingHouse SparrowCommon LinnetLarus argentatusCuculus canorusPrunella modularisTurdus philomelosSturnus vulgarisPasser domesticusCarduelis cannabinaThe song thrush, which in the Isles of Scilly is verytame and occurs in very high densities, is arguably themost significant of these due to that fact. Herring gull,dunnock, common starling and house sparrow are alsopresent in good numbers.The common ringed plover Charadrius hiaticula breedsin small numbers on shingle. The Isles of Scilly areone of a handful of sites in the south-west where theybreed, none of which are in mainland Cornwall.Trends and IssuesResearchAs part of the SPA all breeding seabird species areregularly monitored by the RSPB and NE. The Islesof Scilly Wildlife Trust monitor all breeding birds onAnnet annually apart from burrowing species. TheRSPB also conduct productivity monitoring of 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 of the song thrush forseveral years in the late 1990s to early 2000s, this dataprovides a baseline for this species. Further study ofthe song thrush in the Isles of Scilly might clarify whyit occurs at high densities there, but is in decline inmuch of the rest of Britain.Fisheries ImpactsSome diving birds such as European shags can becaught in gill-nets. The 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 off-islands has been successful,but needs to be monitored and if need-be, continued.TourismHuman disturbance affects the breeding success ofcertain breeding species such as common tern andcommon ringed plover.Isles of Scilly biodiversity audit Page 48


2.2.1.32 Terrestrial MammalsOverviewThe terrestrial mammals include rodents, bats andlarger species, such as deer.Generally speaking mammals are ubiquitous inBritain, but the isolation of the Isles of Scilly meansthat the number of terrestrial mammals that have beenrecorded there is very small (only 10 are certain) andsome of those have been introduced.However, there are at least four species of batsrecorded for the islands, two of which (commonand soprano pipistrelle Pipistrellus pipistrellus and P.pygmaeus) are considered to be resident.Important AreasAmong the small number of terrestrial mammals, onlythe bats are particularly site dependent and coupledwith the fact that they are of conservation concern alltheir breeding and roosting and sites are significant.Conservation ImportanceAll British bat species and their roosts are protectedby the Wildlife and Countryside Act 1981; hedgehogsare also partially protected by this act. Of the eleventerrestrial mammal species in the Isles of Scilly, threeare on the BAP priority list, one of which has beenintroduced. They are:(introduced) West European HedgehogErinaceus europaeusNoctuleNyctalus noctulaSoprano Pipistrelle Pipistrellus pygmaeusThe Scilly shrew Crocidura suaveolens cassiteridum, asubspecies of the Continental lesser white-toothedshrew which is found only in the Isles of Scilly inBritain is significant because of that fact.Trends and IssuesResearchMore research is required in order to fully assessthe status of the various bat species within the Islesof Scilly. In particular, all the nursery roosts andhibernacula need to be identified.Loss of HabitatA number of bat roosting sites and/or hibernaculahave been destroyed in the Isles of Scilly in the past.Nearly all of the destruction has occurred because ofthe demolition or refurbishment of buildings.AgricultureSome agricultural operations, particularly the use ofpesticides, may affect bat populations by reducingtheir food supply – there is evidence of pesticidepoisoning of a single pipistrelle in the past, thoughsome of the chemicals are no longer in use.Public AwarenessAn Isles of Scilly Bat Group which is affiliated to theIoSWT has been set up with the aim of training morelocal people to be bat wardens.Wider public understanding of the small numberof mammals that are found in the Isles of Scilly,including their status and legal protection, would beadvantageous. In particular, the law relating to batsneeds to be widely recognised.Scilly shrew Crocidura suaveolens cassiteridum is a sub-species found only in the Isles of Scilly. Photos: David Mawer and Ben LascellesIsles of Scilly biodiversity audit Page 49


2.2.1.33 Marine mammals – whales,dolphins, porpoises and sealsOverviewThe marine mammals of the Isles of Scilly includelarge and small cetaceans (whales, dolphins andporpoises) and also seals. These charismatic andpopular species are important to the economy of theislands for tourism and play important roles in marineecosystems.Cetaceans are divided into baleen whales (Mysticeti),which use plates of 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, Scilly is visited by oceanicand coastal marine mammals. Some cetaceans areknown here only from records of a single stranding,while for others the waters around the islandsrepresent an important habitat. All cetaceans usingthese waters are so mobile that the waters aroundScilly only represent part of their home ranges (N.Tregenza, pers. comm.).Grey seals Halichoerus grypus are one of the bestknown species that wildlife lovers associate with theIsles of Scilly. They congregate in one area to mate anduse known breeding areas where they are able to ‘haulout’ on the rocks. Scilly is therefore an important sitefor breeding seals. Satellite tracking of grey seals hasshown that they forage over very large distances andtagging shows that seals from Brittany and Wales visitthe Isles of Scilly at times (Westcott, 1993).The grey seal population in Scilly is about 350 strongand is resident there throughout the year althoughsome individuals may travel between Scilly and themainland (Lambert, 2000).Cetaceans are often 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 of 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 Isles of Scillyare to the south of 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.The population of grey seals is distributed betweenthe Eastern Isles, 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 Wildlife and Countryside Act (1981). Theyare also covered by the Bonn Convention (1979) whichprotects migratory species.The harbour porpoise used to be seen daily inScillonian waters until the 1950s. They are still seen inScilly 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 off the Isles of Scilly. They are theBottlenose dolphins Tursiops truncatus are occasionally observed in the waters around Scilly. Photo: Frank GloysteinIsles of Scilly biodiversity audit Page 50


commonest species of 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 offshore populations in this region. Theinshore forms are more likely to be sighted aroundScilly. Sightings of this species are infrequent, theremay once have been a permanent population herebut this would now only be elucidated through asurvey of elderly Scillonian residents. A small groupof inshore bottlenose dolphins uses the inshore watersoff Cornwall and Devon and have also been observedoff the Isles of Scilly. Some static nets such as gill andtangle nets pose a major threat to the survival of thisgroup (N. Tregenza, pers. comm.).Minke whales Balaenoptera acutorostrata, killer whalesOrcinus orca and pilot whales Globicephala melasare rarely sighted off the Isles of Scilly (SeaquestSouthwest, Marine sightings database).Risso’s dolphins Grampus griseus occur occasionally,with several sightings of pods in 2007 (A Hicks, pers.comm.). One fin whale Balaenoptera physalus wasstranded in the Isles of Scilly 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 Scilly. The spermwhale Physeter macrocephalus too is only known froma stranding in 1967 and is generally a rare species thatoccurs off the edge of the continental shelf (CornwallWildlife Trust Marine Strandings Network).Grey seals are an Annex II species in the EU habitatsdirective but are not a UK Biodiversity Action Planspecies. As high level predators, a healthy sealpopulation is a good indicator of the health of themarine environment in general.Unlike most British wildlife, seals have their own Actof Parliament, the Conservation of Seals Act, 1970.Nationally, grey seal populations have been steadilyincreasing since recording began in the 1960s. This islikely to be attributable to lower levels of hunting andchanges in rural economy. Current indications arethat this upward population trend is now levelling off(Marine Conservation Society, 2007).This small, stable population breeds in the Isles ofScilly with pups appearing between August andOctober (Westcott, Parslow, 2007). Although theyare a small proportion of the estimated 123 000 greyseals in the UK, 90% of the UK’s seal population isin Scotland which makes the seals in Scilly relativelyimportant for this area of the country. The Scillonianpopulation accounts for about 40% of the pups born inthe southwest region (Duck, 1996). Furthermore theyare a key tourist attraction and a charismatic speciesfor which the Isles of Scilly are famed. The presenceof grey seals is a qualifying feature, although not aprimary reason, for selection of the Isles of Scilly as aSpecial Area of Conservation.The predictability of seal sightings has meant thata seal watching and seal snorkelling industry hasdeveloped in Scilly. 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 of the Isles of Scilly for many people. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 51


first started in Scilly in the 1930s. In the 1960s and70s there was a government sponsored cull of sealsin the UK to protect fishing interests. Today there isstill some conflict between the interests of fishermenand tour boat operators but since the Conservationof 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.There have been several reliable sightings of commonseals Phoca vitulina, a BAP species, in Scilly, 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 ofsmall cetaceans and this was marked in Scilly. Olderboatmen in Scilly unanimously say that harbourporpoises were sighted almost daily in the past.Recently, sightings have declined but they are stillcommonly seen in summer months.Some of 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 Isles of Scilly arepart of their home range. It is likely that they wereonce here but their ranges have contracted due towhaling. Some of 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 Cornwall now eachwinter (N. Tregenza, pers. comm.).ResearchThe Cornwall Wildlife Trust Marine StrandingsNetwork has representatives in Scilly who recordstrandings (dead and alive) of large marine animalssuch as cetaceans and seals.As a feature of the Special Area of Conservation, greyseals must be monitored a minimum of once every sixyears by Natural England.Fisheries ImpactsCetaceans and seals are vulnerable to entanglementin fishing gear. Investigation of cetacean strandingssuggests that certain static nets such as gill andtangle nets account for a high proportion of thecetacean strandings around the Southwest of England(Cornwall Wildlife Trust Marine Strandings Network2005 & 2006). Cornwall Wildlife Trust’s research hasshown that there is a significant level of bycatch ofporpoises in the Celtic Sea hake fisheriesPelagic and demersal trawl fisheries also lead to acertain level of 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 Scilly are sometimes sighted with fishingnet entangled around them (A. Hicks, pers. comm.).It is often 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. Thereis 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 of the relationship between organochlorineburdens and morbidity show that all the smallcetaceans in Cornish waters are likely to be affectedand the control of organochlorines has been a majorand extremely valuable element in their conservation(N. Tregenza, pers. comm.).Seals are particularly vulnerable to accumulationsof lead and mercury (Duck, 1996). Oil spills can beharmful to marine mammals, especially seals dueto fouling of their fur and inhalation of volatilecompounds; pups are particularly vulnerable to oilspills.TourismGrey seals are probably the single most importantspecies for the Isles of Scilly in terms of tourism. Thereare regular boat trips to observe, snorkel and dive withthe seals. Their 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 Scilly for over 20 years, seals’ reactionto disturbance relates to which site they are at.DiseaseOutbreaks of Phocine Distemper Virus have hadsevere impacts on populations of common seals in thepast. Grey seals can catch the virus but are unlikely todie from it.StormsEvery year seal pups get washed off the rocks,particularly during bad weather. Some are sent toGweek Seal Sanctuary but there are also fatalities.Breeding occurs at a stormy time of year (Parslow,2007).Isles of Scilly biodiversity audit Page 52


Habitat Areas -An IntroductionSt Mary’s (650ha)As the largest island in the Isles of Scilly, St Mary’s isthe centre of life in Scilly with the main town, HughTown and main harbour. A large part of the island isfarmland, both arable and grassland. There are areasof maritime heathland and coastal grassland alongthe undulating and varied coastline. At Higher Moorsis an area of 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. The coastline includes the large promontory withthe Garrison above Hugh Town, dunes, sandy androcky beaches and cliffs. There are also three smallislets just offshore.The Off IslandsThe other inhabited islands are Tresco (297ha), StMartin’s & White Island (238ha), Bryher (133 ha), StAgnes & Gugh (144ha). All have small populations ofislanders living in small hamlets and they mainly relyof farming, fishing and to a large extent, tourism.Tresco is the most wooded island with plantationwoodland and rhododendrons through the middleof the island where the kilometre long Great Poolalmost cuts the island in two. Just north of Great Poolis mainly farmed, and beyond that ‘waved’ heathlandon the higher ground of Castle Down. In the south ofthe 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 of the coast is dunesand sandy beaches.Bryher faces Tresco across a shallow channel. It hasa soft sandy east coast that contrasts with the moreexposed west with its rocky bays. The island is slightlyhilly with a central plain and saline pool. The hills areheathy, with more coastal grassland and heathlandtowards the very exposed promontory of 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 of the island with acharacteristic pattern of small fields at Higher Townmost of which are formed from blown sand. Along thenorth of the island is a band of coastal grassland andheathland right up to the cliffs below Chapel Down inthe east.St Agnes is separated from the main group of islandsby a deep channel. It has a coastland of small rockyor sandy bays. The centre of the island is farmed withmany very small fields with green fences. There is alarge freshwater pool and surrounding meadow inthe north of the island and important heathland areason Wingletang Down in the south and linked (by atombolo) to the rocky, heathy island of Gugh.Annet (22ha)Well–known for its colonies of Manx shearwaters,puffins and storm petrels, Annet is a low-lying islandwith dramatic carns (tors) at its extremities. Muchof the island has unusual vegetation cover of hugethrift tussocks and areas of 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 ofthe abandoned cottages and walls of 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 ParslowIsles of Scilly biodiversity audit Page 53


to lighthouse keepers in the past before automation ofthe lighthouse. They are quite varied in landscape withareas of 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 IslesA group of a dozen or so small islands protectedwithin the circle of the rest of the islands. Generallythey have a well-vegetated and softer appearancethan the Western & Norrad Rocks. The larger islandssuch as Great Ganilly and the Arthurs have areas ofheathland, coastal grassland and sandy bays. Seabirdsand Grey Seals have colonies on many of the islands.Western and Norrad RocksThese are two groups of rocky and extremely exposedislands, stacks and reefs lying in the west of thearchipelago. Few of the islands support any highervegetation but many are important for their seabirdcolonies and seals.The following sections describe these priority habitats:2.2.2.1 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 of marine, terrestrial and freshwater habitats. Photo: RNAS Culdrose SAR flightIsles of Scilly biodiversity audit Page 54


2.2.2.1 Arable Field MarginsOverviewNationally arable wild flowers have declineddrastically both in abundance and distribution. In theIsles of Scilly some arable species formerly associatedwith cornfields that are declining on the mainland arestill relatively frequent. Some species have becomeparticularly associated with the cultivation of bulbfields especially those growing winter-floweringnarcissus. Recently there has been a decline in bulbfarming which is already having an effect on the floraof the bulb-fields.Distribution and ExtentThe small size of fields in the Isles of Scilly 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 Scilly and thesecond in both Scilly and West Cornwall. Many ofthe rare plants found in these communities are winterannuals so are disadvantaged by arable crops thatrequire spring cultivation.In the Isles of Scilly arable communities are foundon all the inhabited islands although the speciescomponent varies from island to island.Although fields in Scilly are not large enough forground-nesting birds to utilise they provide feedingsites for a range of birds.Seeding arable weeds attract large flocks of feedinglinnets and other finches.A number of rare arable plants are found in Scillyincluding shepherd’s needle Scandix pecten-veneris,small-flowered catchfly Silene gallica and westernfumitory Fumaria occidentale.Trends and IssuesThere is a marked loss of bulb-fields in Scilly over thepast ten years. There 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 soft fruit do not support the same range of arableplants.Some fields have been planted with ‘conservationcrops’ (These are seed mixtures designed to beattractive to wildlife but often made up of a varietyof plants frequently not native to the area or evento Britain) or quinoa; such crops do not supportpopulations of arable species.ResearchResearch and monitoring of arable plant communitiesand field margins associated with the bulb fieldsshould be a priority.Conservation ImportanceArable fields with assemblages of arable plants areof nature conservation value for butterflies, bees andother invertebrates.Western fumitory Fumaria occidentale a rare plant of arable field margins which is endemic to Scilly and Cornwall. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 55


2.2.2.2 Coastal Sand DunesOverviewCoastal sand dunes develop where there is a plentifulsupply of 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 of the sand dunes in the Isles of Scilly 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 of aforeland dune and in other places are sand bars calledtombolos – the best example is the Gugh Bar betweenSt Agnes and Gugh. The largest dunes in Scilly areat Appletree Banks on Tresco, around St Martin’sand at Bar Point on St Mary’s. There are lesser dunesand sandy beaches on many islands, especially thosesurrounding the central sand flats off St Martin’s.Conservation ImportanceSeveral of the Scilly SSSIs include areas of 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 of the dune is ruptured ‘blow-outs’can occur reducing the stability of 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 GallIsles of Scilly biodiversity audit Page 56


2.2.2.3 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 of these beaches and sandybeaches although the amount of finer materials mixedin with the shingle, and the hydrological regime, forexample freshwater seepages can influence whichplants occur. The classic pioneer strandline plants inScilly 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. There are also a number ofcharacteristic invertebrates that are found on coastalshingle.Distribution and ExtentThe Isles of Scilly have a number of shingle structuressuch as bars, raised beaches and shingle beaches. Theshingle community SD1 is quite widespread in Scillywith examples from the Western Rocks, Annet, EasternIsles and other islands. These 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 Scilly 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 IssuesThe shingle beaches are most under threat from sealevel rise and increased storminess. The loss of shoredock in some places can be related directly to erosionby storms.Shingle beaches are vulnerable to pollution, especiallyfrom oil spills.The shingle beaches are subject to massive amounts ofplastic rubbish and non-biodegradable detritus frompassing shipping and from other sources.Shore dock Rumex rupestris grows on coastal vegetated shingle but has declined in Scilly. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 57


2.2.2.4 Fragile Sponge andAnthozoan Communities onSubtidal Rocky ReefsOverviewThe 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 theIsles of Scilly appear to fit this category. The graniticreefs and islets surrounding the main islands havewalls covered with abundant anemones and softcorals (anthozoans). Particularly characteristic of thesewalls are jewel anemones Corynactis viridis, plumoseanemones Metridium senile and dead man’s fingersAlcyonium digitatum. These colourful and spectacularcommunities are one of the main attractions for divingtourists. Close by, usually less exposed to the currentthere are often diverse communities of sponges suchas Axinella damicornis.Physically all of 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 of the three primary reasons that the Isles of Scillywere selected as a Special Area of Conservation is thepresence of reefs. Reefs are an Annex 1 (EU HabitatsDirective) habitat and they surround the islands,allowing the development of faunal communities suchas sponges and anthozoans.Distribution and ExtentRocky reefs are extensive around the Isles of Scilly,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.These reefs occur outside the shelter of the ring ofislands, for example sites such as Trenemene in theWestern Rocks, the Crim Rocks, the Gilstone near StMarys and Hard Lewis near St Martins. These habitatshave not been mapped hence the full extent of thishabitat is currently unknown.Fragile sponge communities occur particularly on themore sheltered eastern sides of the islands in over 25mof water. These 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 of 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 GloysteinIsles of Scilly 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 of 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 of Special Areas of Conservation in theUK based on the presence of reefs. In the Isles ofScilly, reefs are one of 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 of the sitessurveyed are areas of rocky reef which support thishabitat. Some reef sites have been surveyed repeatedlyat yearly intervals. Surveyors record species presentand other features of the habitat with abundanceestimates for each species.The great wealth of knowledge of the local diveoperators should be recorded for scientific andeducational use. Photographic records collected overyears of 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 of the islands there is evidence that damagehas occurred to fragile sponge and anthozoancommunities as a result of 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 of coastal development. Depositionof this silt can easily damage fragile spongecommunities.Isles of Scilly biodiversity audit Page 59


2.2.2.5 Hedgerows and BoundaryFeaturesOverviewThere are virtually no true native hedgerows in theIsles of Scilly. The few hawthorn Crataegus monogynahedges that exist on St Mary’s are of little conservationinterest. Although not a BAP habitat there are anumber of different boundary features in the Isles ofScilly.Stone ‘hedges’ come in three main types, dry-stonewalling (single leaved), ‘Cornish hedges’ (doubleleaved) and granite masonry (such as the Garrisonwalls). Then there are green ‘fences’ of various speciesof 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 windbreaksof 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 ExtentThere are many kilometres of 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 of stone are an importancerefuge for many plants, particularly species such aswestern fumitory and ferns. They are also refugesfor invertebrates - some are used as nesting sites bysolitary bees, and mammals including the Scilly shrew.Dry-stone or single-leaved hedges also supportpopulations of lichens, ferns and other plants andprovide shelter for mammals and invertebrates.The mortared walls also act as refuges to many plants.The tops of 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.The evergreen fences are important sites for nestingbirds; song thrush, blackbird, linnet, dunnock andoccasionally by house sparrow.Trends and IssuesThe use of herbicides to clean stone hedges has led toloss of species.Neglect has led to bramble and bracken overwhelmingsome stone hedges.Neglect allows loose stones to fall, leading todisintegration and instability of stone hedges.Work is needed with the farming community to ensuresympathetic conservation of field boundaries.ResearchAn investigation could be made to determine thecomparative value of the green fences both as shelterand for nature conservation.Stone hedges on St Martin’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 60


2.2.2.6 Intertidal BouldersOverviewShores in Scilly range from the super-exposed to fairlysheltered and the intertidal boulders support differentspecies assemblages depending on the degree ofexposure (Hiscock, 1985). The more exposed shores aretypically animal dominated whereas in embaymentsthe rocky shores are dominated by brown algae.Typical zonation of plant and animal communitiescan often 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 Scilly supportrich under-boulder communities (Parslow, 2007).Rockpools are present on some shores, their speciesassemblages reflect their position on the shore, withsome of the highest pools only being replenished atextreme high water spring tides.Distribution and extentThere are about 97km of rocky shore in Scilly(Parslow, 2007). Although some of 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. There is a risk that manystudents carrying out fieldwork in the same area couldnegatively impact the habitat. The original bouldersurveys in Scilly 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 oftencontain a diverse range of species. The rocky shore isan ideal outdoor classroom where many ecologicalprinciples can be seen. They 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 Biodiversity 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 of rocky shorewith different levels of exposure. A total of 128 algal,13 lichen and 237 macroscopic animal species wereidentified on the rocky shores.The intertidal boulders of Scilly are the nationalstronghold for the BAP species Paludinella littorina,the lagoon snail (Light and Kileen, 2001). The boulderhabitats on sheltered shores in Scilly are particularlyrich examples of their type and of high natureconservation interest (Fowler, 1991).Rocky intertidal areas are used as haul-out sites bygrey seals, which are a feature of the Special Area ofConservation.St Martin’s sedimentary shore is a designated Site ofSpecial Scientific interest. This includes some areas ofintertidal boulders but these are incidental as the mainpurpose of the designation was to protect the sandflats.Rockpools which form in areas of intertidal boulderssupport a diverse array of species and are importantfor juveniles of many fish and other species.Sand and boulders in the intertidal zone. Photo: Angela GallIsles of Scilly biodiversity audit Page 61


2.2.2.7 Lowland Dry Acid GrasslandOverviewAcid grasslands occur over acid rocks such as thegranites that form the bedrock of the Isles of Scilly.Although the habitat is typically species-poor severaldifferent NVC plant communities occur in Scilly.These 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 of 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 of plantspecies such as heath bedstraw Galium saxatile,sheep’s-fescue Festuca ovina (frequently replaced inScilly 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 2.2.2.8), especially incoastal situations. In many places acid grasslands canhave a high cover of bryophytes and acid grasslandcan be rich in lichens especially near the coast.Distribution and Extent.Figures for the amount of acid grassland in the Isles ofScilly 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 of grazing or abandonment leading toinvasion by coarse grasses and bracken Pteridiumaquilinum.Lowland dry acid grassland at the coast on Gugh. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 62


2.2.2.8 Lowland HeathlandOverviewLowland heathland is a rare and threatened habitatnationally and internationally. The Isles of Scilly haveareas of good quality lowland heathland on almostall the inhabited and larger uninhabited islands, alsoareas of more degraded heath on the inhabited islands.In the Isles of Scilly heathland is characterised by thepresence of dwarf shrubs such as ling Calluna vulgaris,bell heather Erica cinerea, common and western gorseUlex europaeus and U. gallii. Within the heathland areareas of 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 Isles of Scilly the heathlands are mosaicsof 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). Theyalso typically merge into cliff communities near thecoast. In more open places there are extensive areas of‘waved heath’ the product of extreme wind-pruningthat is very typical of the exposed ground in Scilly.Distribution and ExtentMost of the coastal areas on St Mary’s and the ‘offislands’ have areas of 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. The coastal heathlandcommunties, sometimes referred to as maritimeheathland (which on Scilly is a category that overlapswith lowland heathland and is characterised by theinfluence of salt spray), are nationally important withmany areas within SSSIs.Trends and IssuesAn unknown amount of 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 remainsof field boundaries are still evident in places. Someof this is now reverting to heathland when fields areabandoned.Lack of management and inappropriate managementis the most significant issue. Much heathland hasbecome invaded by bracken and common gorse.There has been a diminution in the amount anddistribution of 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 lackof stock. In the first half of 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.The Waves of Heath project (2003-2008) is partof Tomorrow’s Heathland Heritage, a UK wideprogramme supported by the Heritage Lottery Fund.The Waves of Heath project aims to restore and bringinto appropriate management substantial areas ofScilly’s maritime heathland and enhance people’senjoyment and understanding of heathland througheducation. Partners in the Waves of Heath project arethe Isles of Scilly Wildlife Trust, Natural England, theDuchy of Cornwall and Tresco Estate.Waved heathland on St Martin’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 63


2.2.2.9 Lowland MeadowsOverviewThese are lowland grasslands usually managed ashay meadows or pasture, excluding acid grasslandand maritime grasslands that are included elsewhere.In terms of National Vegetation Classification plantcommunities, they primarily embrace several typesof grassland, particularly the MG5 Cynosurus cristatus- Centaurea nigra grassland. Although there werehay meadows in Scilly 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 Isles of Scilly and althoughnone probably strictly conform to the BAP habitatdescription they are included here.Distribution and ExtentIn the Isles of Scilly this is a rare type of 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 of this type of 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 of fertiliser.This is a generally under-recognised habitat in the Islesof Scilly.Some of the grassland areas provide feeding areasfor birds and are attractive to butterflies and otherinvertebrates.The Plains on St Martin’s are derived from shell sand and support calcareous species. Photo: Angela GallIsles of Scilly biodiversity audit Page 64


2.2.2.10 Marine Sands and GravelsOverviewThe intertidal and subtidal sand flats of the Isles ofScilly are extensive and nationally important dueto the diversity of their associated fauna. They arecomprised of two habitats listed on Annex I of the EUHabitats directive and are the main features whichhave triggered the selection of the Isles of Scilly as aSpecial Area of 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 BiodiversityAction Plan habitat.The intertidal and subtidal sandy sediment areas arecontiguous within the Isles of Scilly and are thereforestructurally and functionally linked – they are beingconsidered together in this document. These areas areunusual due to their remoteness from most humanimpacts and from sources of freshwater. The sedimentis derived from granite and is coarse grained, evenin sheltered areas; the sands have low silt content asthere is very little input of alluvial sediment and lowlevels of pollution.Stable sediment areas support a rich infauna ofburrowing invertebrates such as worms, bivalvemolluscs, urchins and anemones as well as mobilefauna like shrimps, crabs and fish. The presence ofcoarser 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 of amphipods and other meiofauna.Distribution and ExtentThe largest and most important areas of 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 of sandflats are visible at low water, particularly south of StSandflats at Samson – the remains of old field margins are visible on the sand. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 65


Martin’s; east of Samson; between Bryher and Tresco(Tresco flats) and adjacent to Old Grimsby on Tresco.The largest of these is St Martin’s flats, a SSSI south ofSt Martin’s.The extent of the sandflats can be seen on nauticalcharts of the area. Much of the soft sediment is coveredby seagrass beds and these areas have been mapped.Conservation ImportanceBoth the intertidal sandflats and the subtidalsediments are of European and National significancebecause of their extent and the richness and diversityof their associated communities (Natural England,Natural Area Profile). They 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. There aresubstantial differences between the communities ofeach of 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.The shallow sublittoral and interlittoral sedimentssupport some of the most extensive and welldeveloped areas of seagrass beds in the UK. Seagrassbeds are a BAP habitat themselves and are consideredseparately within this document [Section 2.2.2.15].The area of intertidal sand flats adjacent to the islandof St Martin’s has been protected as a Site of SpecialScientific Interest (SSSI number 2000168) since 1996.These and other sand flats throughout the archipelagosupport aggregations of 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 AreaProfile). In some areas such as Old Grimsby Harbour,Tresco, the density of Echinocardium cordatum is upto 25 per square metre (Nichols and Harris, 1982).The razorshell Ensis siliqua biotope is nationallyuncommon but is widespread in Scilly. Densepopulations of burrowing anemones occur on some ofthe 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.These areas generally occur between the islandswhere exposure and tidal influence are greater. Thecommunities include nationally rare species such asthe red seaweeds Cruoria cruoriaeformis (A UK BAPspecies), Gelidiella calciocola and Schmitzia hiscockiana.These stony areas may also support large populationsof the gastropod Gibbula magus, at population densitiesof 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 of Scilly due to the mild climate andexposure to oceanic currents which transport larvae.Examples of these in sandy substrates in Scilly arethe spiny cockle Acanthocardia aculeata, a hermit crabCestopagurus timidus and the trumpet anemone Aiptasiamutabilis (English Nature, 2000).Trends and IssuesResearchThe SSSI at St Martin’s flats is monitored by NaturalEngland as part of their commitment to monitoringthe Special Area of Conservation features. This iscarried out at least once every six years. The methodinvolves monitoring the infauna of the sediment ofthree 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 of 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 Isles of Scillydown to the 10-metre depth contour line (EnglishHeritage, 2004).Tourism / RecreationAt low tide large areas of sandflats are exposed andmay be used for recreation. There has been no study ofthe effects of 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.Isles of Scilly biodiversity audit Page 66


2.2.2.11 Maritime Cliff and SlopesOverviewAlthough there are no very high cliffs in the Islesof Scilly there are cliffs and slopes all around thecoastline of the islands. As the definition also includesthe landward extent of the influence of deposition ofsalt spray (about 500m) many of the smaller islandsand large areas of the main islands are involved. Sothere is considerable overlap with inland habitats suchas lowland dry acid grassland and lowland heathlandand there is often no obvious demarcation. On theseaward side, the plan extends to the limit of thesupralittoral zone and so includes the splash zone andthe lichens and other species occupying this habitat.The vegetation of maritime cliff and slopes variesaccording to the amount of exposure to wind and saltspray and the geology of the underlying rocks. Themost maritime vegetation types are found where thereis greatest exposure to the elements – in Scilly 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 modicumof shelter, plants of 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 ofred fescue Festuca rubra is a constant component ofseveral 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. Speciesof inland grasslands that also commonly occur inmaritime grasslands include ribwort plantain Plantagolanceolata, bird’s-foot trefoil Lotus corniculatus, commonrestharrow Ononis repens and several species of grass.On cliffs and slopes more sheltered from the prevailingwinds and salt spray, the vegetation communitiesare more similar to those found inland. The uppersections and cliff-tops of hard cliffs on acidic rocksmay support maritime heaths characterised by heatherCalluna vulgaris.Maritime cliffs are often significant for theirpopulations of breeding seabirds, many of which areof international importance. Some areas of softer ramcliffs provide nesting sites for solitary bees. Thereare also seepages and springs at the base of the cliffsthat provide additional habitat for invertebrates andcoastal plants including shore dock Rumex rupestris.The supralittoral zone represents the lowest belt ofterrestrial vegetation on maritime cliffs and is usuallynotable for a zone of orange and grey maritimelichens. These include Caloplaca marina, Ramalinasiliquosa and Verrucaria maura, also uncommon speciessuch as Roccella filiformis and R. phycopsis.Distribution and ExtentThis is one of the most extensive habitats in Scilly.Cliff communities are found on all the inhabited andthe larger uninhabited islands. Due to the constanteffects of salt spray and winds in many places the cliffvegetation merges seamlessly into the more inlandheathland and grassland communities.Conservation ImportanceThese maritime habitats are a feature of southwestBritain. Those around the Isles of Scilly have linkswith those of Cornwall, especially the Lizard, but alsohave significant differences in geology and speciescomposition.Threats and IssuesMany of the cliffs in Scilly are subject to severe erosiondue to undercutting of the softer 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 of 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 ParslowIsles of Scilly biodiversity audit Page 67


2.2.2.12 PondsOverviewPonds are small bodies of 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 ExtentThere are small ponds on a number of the inhabitedislands, some of which may have been man-made towater livestock. Many of them are slightly saline attimes due to percolation through dune banks from thesea, directly through leats or from wind-blown saltspray. There are also pools on the larger uninhabitedislands, some of which are seasonal.Conservation ImportanceMany of the ponds have a fluctuating flora withplants typical of the NVC Ranunculus baudotii(A21) community. These pools may contain beakedtasselweed Ruppia maritima and fennel-leavedpondweed Potamogeton pectinatus as well as thebrackish water crowfoot Ranunculus baudotii. Some ofthese 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 of bulbous rush Juncus bolbosus. Thesmall 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). The 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.These pools also have an invertebrate fauna, largelyunrecorded and may also be of ornithologicalimportance, especially for migratory birds.Trends and IssuesOn St Mary’s several ponds have suffered fromenrichment due to large numbers of residentwaterfowl, including exotic ducks that are fed by thepublic and breed freely.The invasion of the water fern Azolla filiculoidesinto several ponds led in the past to an extremeprogramme of herbicide use in an attempt to clear thefern. This also had a detrimental affect on the existingflora of 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.The loss of brackish water crowfoot Ranunculusbaudotii from many of the ponds where it was formerlyfound suggests there have been changes in the waterquality or other adverse factors. The 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 of ‘improvingpools’ in this way should be discouraged.Pool on St Martin’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 68


2.2.2.13 ReedbedsOverviewReedbeds are wetlands dominated by stands of thecommon reed Phragmites australis, where the watertable is at or above ground level for most of the year.In Scilly they tend to incorporate areas of open waterand ditches, and small areas of wet grassland andoften willow carr Salix cinerea. Some of the Scillyreedbeds, 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 ExtentThe reedbeds in Scilly are all quite small althoughtheir nature conservation value is significant and mostare SSSIs. There 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 Scilly very little isknown about the invertebrate fauna of the reed beds.Reedbeds in Scilly were formerly more extensiveand wetter before land clearance, modification to theditches and water abstraction.Trends and IssuesLack of or inappropriate management ofexisting reedbeds has led to drying and to scrubencroachment.Some areas of reeds have been lost over the pastcenturies. They 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 ofthe water table and changes in vegetation. There areWater-level Management Plans for Lower & HigherMoors.The 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.The significance of the endemic form of the sea rushJuncus maritimus (var atlanticus) needs recognition;some stands of the rush should be retained.Higher Moors on St Mary’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 69


2.2.2.14 Saline LagoonsOverviewSaline lagoons are water-bodies that have links withthe sea. They retain part of the seawater at low tidesand can be brackish or saline, even super-saline. Theirconnection to the sea may be by percolation through asea bank or through a natural or man-made channel.DistributionIn the Isles of Scilly 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 of beakedtasselweed Ruppia maritima, fennel-leaved pondweedPotamogeton pectinatus and with a narrow band ofsaltmarsh plants including saltmarsh rush Juncusgerardii, lesser sea-spurrey Spergularia marina andcommon saltmarsh-grass Puccinellia maritima aroundthe perimeter.The fauna has a fluctuating population of 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 & IssuesThe lagoon is vulnerable to pollution, especially fromthe overflows or run-off from the nearby hotel. Thereis also a large rubbish pit not far away.The leat and sluice must be maintained in goodorder to protect the lagoon and the water quality/salinity.The pool should be protected from any futuredevelopment of the hotel that may have adverseeffects on the water quality.Bryher with the saline lagoon clearly visible. Photo: RNAS Culdrose SAR flightIsles of Scilly biodiversity audit Page 70


2.2.2.15 Seagrass BedsOverviewSeagrasses are the only group of truly marineflowering plants. They grow in beds or meadows insoft sediment which is sheltered from strong waveaction. In the UK they maybe found from the uppershore, to a depth of 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). The two speciesof 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 of leaves,roots and rhizomes and the structural complexityof the beds offers a variety of ecological niches forother species. Zostera communities can be composedof numerous species of algae, hydroids, anemones,molluscs and fish. They are particularly important asspawning and nursery areas for many fish species,some commercially important. They 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 of seagrass beds in Scilly isthe presence of ring shaped areas of eelgrass withbare sand in the centre. These ‘doughnuts’ are fairlycommon here and may be a result of current actiondislodging the centre of the bed and a ‘blow out’forming (Fowler and Pilley, 1992). They also appear inthe algal communities. Another possible explanation isthat they are a result of the underlying archaeology (R.Parslow, pers. comm.).Distribution and extentFollowing its loss from many areas of the country dueto a wasting disease in the 1930s, the Isles of Scilly hasbecome one of the most important areas nationally forZostera marina var. marina beds. However, even in Scilly,the once vast meadows of seagrass which extended overhundreds of acres of 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 of 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 of seagrass beds. Themajority of 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 ofseagrass.Some mapping has been carried out based onaerial photography during the 1980s and 90s. In1999 a student from Plymouth University mappedthe distribution of the Zostera beds using aerialphotographs and a GIS based technique andestimated the total area to be approximately 307ha(3.07Km2). Analysis of all available aerial survey databy Hocking and Tompsett, 2002 gave an estimate oftotal area of 348.25ha.Five main seagrass beds exist in the Isles of Scillyand the Zostera Survey Team hopes to carry outgenetic analyses to determine whether these separatepopulations were once one large area of seagrass.Conservation ImportanceThe seagrass beds of the Isles of Scilly are the mostextensive in the whole of the southwest and are ofvery high conservation importance due to their extentand the richness of their associated flora and fauna(Hocking and Tompsett, 2002). The 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 of thekey reasons that the Isles of Scilly is a Special Area ofConservation (SAC).Seagrass beds are a national BAP habitat and havea national Habitat Action Plan and a South WestRegional Biodiversity Action Plan. Natural Englandcategorises the seagrass beds of Scilly as being ofinternational importance. In Scilly the most diversefaunal communities of any sedimentary area are foundamong the roots and rhizomes of the Zostera beds, anarea of particular diversity is found in the seagrass atRushy Point, Tresco (Nichols and Harris, 1982).Both species of Zostera occurring in the UK areconsidered to be nationally scarce (occurring in 16-100ten km squares).The Zostera beds do not fall within any of the SSSIs inScilly.Seagrass beds in Scilly support many speciesincluding large numbers of juvenile fish (A Hicks,pers. comm.). Within the Zostera communities thereare some rare southwest species of algae includingnationally rare Asparagopsis armata. They also supportthe nationally rare hydroid Laomedea angulata andprobably two species of 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 theIsles of Scilly biodiversity audit Page 71


eelgrass beds in Scilly. This species on the IUCN RedList of 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. They are very highly sensitive to substratumloss, smothering, turbidity, wave exposure andnutrients and highly sensitive to displacement.Coastal development, dredging, run-off, mooring andanchoring are all issues which have the potential tonegatively influence seagrass beds.ResearchMonitoring of the eelgrass beds was started byHiscock in 1984 and continued almost annually until1991 by the Nature Conservation Bureau on behalfof 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 ofseagrass. Following this, monitoring was conducted bythe Zostera Survey Team, which continued to submitreports to English Nature.There is a lack of good historical baseline data butoverall there currently seems to be a declining trend inseagrass abundance.In 1986 Hiscock studied the associated algae of theZostera beds.Natural cyclesZostera beds die back naturally in the winter months,re-growing again in spring. Furthermore seagrassesare naturally variable as a result of environmentalfluctuations such as sunlight intensity, freshwaterpulses, exposure to air and severe storms. Theseenvironmental stressors can cause die-backs and thisnatural variability should be taken into considerationwhen assessing human impacts on seagrass. Variationsin populations of epiphyte grazers such as thegastropod Nucella lapillus can also influence the healthof 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 of the plant and may be introducedto the food chain.In Scilly, where untreated sewage is dischargedinto the marine environment there is a potential forthe elevated nutrient levels to impact the seagrass.Nutrient run-off and suspended sediments fromagricultural fields could also affect the Zostera beds.DiseaseIn the 1930s a wasting disease killed much of theseagrass around the coast of Britain. Symptoms ofthis disease, which is caused by the slime mouldLabyrinthula were observed in Scilly during the 1980sand 90s (Fowler, 1992) and reductions in the extent ofthe seagrass beds may be attributable to the disease.The disease is still present in the population butmainly affects the outer leaves of the plants, not theinner, newly growing seagrass blades (K. Cook, pers.comm.).Invasive SpeciesThere is a suggestion that the seagrass beds in the Islesof Scilly 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 often grows can erode orsmother seagrass beds. An increase in the numberof fast boats in Scilly 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 Scilly trawling only occurs in deeperSeagrass Zostera marina forms meadows in the clear, shallow,sheltered waters near the islands. Photo: Tom ReidIsles of Scilly biodiversity audit Page 72


2.2.2.16 Standing Open Water(Eutrophic Standing Waters andMesotrophic Lakes)OverviewStanding open water includes all the larger waterbodies in Scilly over two hectares in extent. Someare categorised as mesotrophic lakes, but they arenot typical and most are affected by occasional saltintrusion. The BAP habitats eutrophic standing watersand mesotrophic lakes are both included here as it hasnot yet been determined in which category most ofthese water bodies in the Isles of Scilly belong.Distribution and ExtentSome, but not all of the larger water bodies in Scillyhave associated reedbeds. Others may be surroundedby sea club-rush Bolboschoenus maritimus or sea rushJuncus maritimus.Conservation importanceVery little information is available about the flora ofthe lakes in Scilly and even less of their invertebrateand vertebrate fauna. Some of the plant speciesrecorded in earlier accounts are no longer presentand there appear to be considerable fluctuations inthe abundance and species of aquatic plants. Manyof the lakes are of 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 IssuesThe two wetland ‘Moors’ on St Mary’s are locallyimportant as water abstraction sites and have beenconsiderably modified to fulfil the requirements ofboth the IoS Council and nature conservation. Sluicesand other structures keep salt water from the siteand also keep levels of freshwater high at abstractionpoints. Both sites are subject to agreed WaterManagement Plans.There is a sluice on Tresco Great Pool which drainsinto the sea. But some saltwater intrusion may stilloccur at times.There have been potential pollution incidents in theditches that feed the lakes; pollution is always a riskwith the rubbish tip, agricultural run-off and otherpossible sources close by.The water fern Azolla has begun reinvading someof the lakes again and there is no easy or obviousdeterrent.Photo:Isles of Scilly biodiversity audit Page 73


2.2.2.17 Tide-swept ChannelsOverviewThe tidal range in Scilly is about five metres duringspring tides. Strong tidal streams are unusual inScilly and are rarely in excess of 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 of particulate foodin the water. Filter feeders make use of the currentswhich deliver particles of food to their extendedfeeding apparatus. These communities typicallyinclude soft corals, hydroids (sea firs), bryozoans(sea mats), large sponges, anemones, mussels andbrittlestars. Tide-swept channels may supportcommunities of marine algae with long fronds suchas kelps and thongweed (UK Biodiversity Group).Tide-swept cobble habitats in Scilly have rich algalcommunities, considered to be of national importance(Barne et al, 1996)The Isles of Scilly have been noted as providing agood example of tide-swept communities of nationalimportance (UK Biodiversity Group).Distribution and extentThere are channels between some of 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. These channelsare up to 20m or so deep and the effects of the tidescan be felt all the way to the bottom. There 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. The habitat has not yetbeen formally described therefore interpretation of thistitle is somewhat subjective.Constant movement of 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 Scilly in his speech at the Wave and Tidalconference of the British Wind Energy Association,2007. In the future there is a possibility that theseresources will be exploited as a source of renewableenergy.ResearchHiscock (1984) categorised survey sites according toexposure to wave action and to tidal streams.Boating ImpactsThere is some mooring of boats in tide-swept channels.For example Teän Sound has a number of 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 NimmoIsles of Scilly biodiversity audit Page 74


2.2.2.18 Wet WoodlandOverviewThis habitat is mostly found in the large fen habitats asareas of willow and alder carr. On Scilly the majorityof it is a form of fen woodland.Distribution & ExtentThere is very little woodland in Scilly and none thatcould be described as Ancient Woodland. Somewet woodland exists as part of a larger complex, forexample willow carr in Higher and Lower Moors.Other woodland has arisen partly by invasion of elmUlmus hollandica into willow woodland as in the HolyVale Nature Reserve.Conservation ImportanceMost of the wet woodland in Scilly 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 ofthese areas, they are known to be attractive to birds,especially migrants and the large amounts of deadwood suggest there may be invertebrate interest. Fernsand bryophytes appear to be well represented.Trends & IssuesThere 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.The stream at Higher Moors on St Mary’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 75


3Issues affecting Isles of ScillybiodiversityThe following issues have been identified as having some influence on the Isles of Scilly’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 of historic and current trends influencing biodiversity· Major policies, schemes and organisations involved· Relevant sub-issues with respect to the Isles of ScillyThis section provides an overview to the influences and pressures on biodiversity and should provide a baselinewith which to inform debate during production of any action plans or further work.Lowertown Quay on St Martin’s. Photo: Angela GallIsles of Scilly biodiversity audit Page 76


3.1 Nature ConservationOverviewPublic appreciation of wildlife conservation hasdramatically increased over the last 50 years; this islargely a result of a growing interest in wildlife andan elevated level of public awareness at the rate whichbiodiversity is changing. It is generally perceived tobe in overall decline. The growth in both statutory andvoluntary organisations has occurred simultaneouslyover the same period.There are currently a wide range of natureconservation organisations, incentive schemes,laws, site designations and policies that impact onthe biodiversity of the Isles of Scilly. A significantproportion of the islands’ land and marine holdingsis subject to some form of conservation designationor protection. There are a number of organisationsand individuals playing important roles in conservingand enhancing the biodiversity of the islands andsurrounding waters.Major Policies, Schemes and OrganisationsThe major players directly involved in natureconservation on the islands are Natural England,Isles of Scilly Wildlife Trust, Royal Society for theProtection of Birds, Isles of Scilly Council, the Duchyof Cornwall, Isles of Scilly Bird Group and the TrescoEstate. A large proportion of 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.The approximate coverage on the Isles of Scilly ofdifferent site designations and/or reserves is asreported below.overview of the funding opportunities open to them.IssuesCooperationThere is always potential for conflict of interestsbetween organisations or the possibility of theduplication of conservation effort. In particular theIsles of Scilly Wildlife Trust was under resourced andwas responsible for managing 60% of the terrestrialland cover of the islands (excluding Tresco). Thisis being partially alleviated by a closer cooperationbetween the Trust and their close neighbours inCornwall.Site DesignationsLarge swathes of the terrestrial land and all of themarine habitats up to the 50 metre depth contourare subject to one or more statutory or non-statutorydesignations. These require significant managementwith limited resources.Of the 26 SSSIs, most are reported to be in asatisfactory condition. There is little reported loss ordegradation of semi-natural habitat, although thereremains a paucity of 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 of awareness of theimportance of key conservation sites and habitat. Thishas been addressed and biodiversity and conservationare at the forefront of the Isles of Scilly Local Planadopted in 2005.Site DesignationArea (Hectares)Conservation AreaAll of the Isles of ScillyHeritage CoastAll coastlineArea of Outstanding All of the Isles of ScillyNatural Beauty (AONB )Ramsar Site401.64haSpecial Protection Area 401.64 haEU Habitats Directive (SPA)Special Area of Conservation 26,851 ha (of 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 of sources with both grantsand incentive schemes being actively promoted e.g.Higher Level Stewardship for significant amountsof the Isles of Scilly Wildlife Trust holdings. It isimportant that all organisations involved maintain anIsles of Scilly biodiversity audit Page 77


Isles of Scilly biodiversity audit Page 78Map of the Isles of Scilly showing selected site designations


3.2 AgricultureOverviewAlthough tourism is undoubtedly the mainstay ofeconomy of the Isles of Scilly, the favourable climateis conducive to early flower production and largesections of 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 of a dedicated abattoir for theislands remains a limiting factor in wider expansion oflivestock for meat farming. The impact of 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 Isles of Scilly, the farming community ispredominantly tenant farmers renting land fromthe Duchy of Cornwall or the Tresco Estate on thatprivately owned island. There 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 of the islands. Flower growing hasbecome considerably less profitable in recent years,mainly due to large importations of flowers into theUK.IssuesViable Agricultural PopulationThe number of 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 of production and used for otheractivities, leaving only best and most sheltered landused for narcissus.Bulb fields on St Mary’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 79


Flower and Bulb GrowingScilly is renowned for the quality and technicalcompetence of flower and bulb production. Combinedwith the favourable climate, this allows a start to theflower season very early (in September) and maintainsa six month period of production. Producers are ableto get produce on the market significantly earlier thanmost mainland competitors, provide continuity ofsupply 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 ofhigh 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 of smallholders and tenant farmers inthis sector and these skills need to be enhanced toensure Scilly remains at the forefront of the industry.The presence of 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 of this.There 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 SchemesThe use of agri-environmental funding can beinflexible and targeted at crops not viable on Scillyand their use is very limited on the islands. The lackof many of these schemes on the islands will havean impact on biodiversity. There is further workunderway to identify ways of incorporating SingleFarm Payments into the agricultural uniqueness of theislands as there would be significant environmentalbenefits to be gained.the Tresco Estate, particularly in the arable margin andhedge habitats.DiversificationThe requirement for smallholders and tenantsto maintain a level of sustainability may lead tothe requirement to diversify outputs outside ofagriculture. The 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 ScillyFarmers have formed a cooperative called the “Groupof 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 of 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 of a movetowards more use of locally produced food within theIsles of Scilly. A local food directory has been set up andmany local restaurants and hotels are moving towardsgreater use of local seafood and farm produce.AbattoirThere is currently no abattoir on Scilly, which limitsthe production of meat on the islands. Plans have beenput forward for an abattoir on St Marys and the Islesof Scilly Wildlife Trust is supportive of this, althoughthe economic viability of such a project remainsan issue. There is potential for the project scopeto be widened into a holistic facility for handling,processing, branding and marketing a range of localproduce. This would have the added advantage ofpromoting agricultural diversification and may attractadditional funding. Furthermore, the widening of therotation on the farmed land by growing foraged crops(for cattle feed) would enhance soil fertility and benefitthe narcissus crop by lessening the impact of 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 of the unique environmentalheritage of the islands. Higher Level Stewardship(HLS) is being pursued by some tenant farmers and byIsles of Scilly biodiversity audit Page 80


3.3 FisheriesOverviewFor many years fishing was one of the major economicactivities in Scilly but the industry has dwindledand fishing now accounts for about 5 percent of 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 Scilly and is important for tourism. Withinthe territorial waters of the Isles of Scilly fishing iswell regulated by national laws and a series of 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 of the Isles ofScilly Sea Fisheries Committee.Major policies, schemes and organisationsLocally, fisheries are managed by the Isles of Scilly SeaFisheries Committee (SFC) of the Council. The 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 officer 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 of their work. Through a cross-warrantingagreement Cornwall SFC also have the power toenforce fisheries legislation in Scillonian waters. Ifthe new marine bill is passed then the Isles of ScillySFC may be lost as the bill aims to centralise fisheriesmanagement. It is likely that the responsibilities ofthe Isles of Scilly SFC would then be taken over byCornwall County Council.There are currently about 30 registered fishing boatsin Scilly (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. The other boatsare mainly used for shellfish potting and small-scalenetting. Potting targets mainly edible crab, spider crab,velvet crab, lobsters and crawfish. Most of the nettingis for mullet, monkfish and turbot (M. Pender, pers.comm.). Between April and November fishing boatsfrom the mainland may fish in the waters off Scillyover neap tides, returning to the mainland to landtheir catch before the spring tides.Some of the fish and shellfish are sold to localrestaurants and hotels and the rest is sold at Newlynfish market in Hayle (both on the mainland). Theshellfish 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.The trawlers operate all year round but the other boatsgenerally only work between May and OctoberThere is a Fishermen’s Association which actsvoluntarily to improve sustainability and to providea voice for local fishermen in relation to policy andregulations. They have introduced a v-notchingscheme for female lobsters; the tails of berried femalesare notched as the fishermen catch and release them,which means that it will be illegal (under a bylawapplying to the Cornwall 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 Scilly, particularlywith summer visitors and several boats are availableto take sport fishermen out to offshore reefs. Shorebased anglers mainly target wrasse, mackerel, pollack,mullet and flatfish. Boat fishing targets similar specieswith the addition of ling, cod and whiting as well assharks and rays. Sharks caught during these trips aretagged and released as part of 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 of conduct, shrimping is authorised between1st July and 30th September each year. Duringstakeholder consultation for the Area of OutstandingNatural Beauty management plan, concern wasexpressed that the current level of shrimping activitymay be too high.The National Lobster Hatchery at Padstow has workedwith members of the Sea Fisheries Committee andlocal divers to release 500 juvenile lobsters in 2002 and120 in 2007. These were released by hand in suitablehabitats and will take many years to grow largeenough to enter the fishery.IssuesLegislation / policyThe fisheries of the Isles of Scilly 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 of 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. There are currently three bylaws:Isles of Scilly biodiversity audit Page 81


1. Prohibits the use of 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 of scallopers with more than4 dredges within the Sea Fisheries District out to4 nautical miles.3. Prohibits removal of lobsters with a carapacelength of 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. The Area ofOutstanding 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 of mackerel has fallensince the mid-1980s (Jones et al, n.d.). Managementmeasures can be brought in to tackle these declines butstocks of some species have continued to fall.Bycatch / non target speciesOne of the problems associated with most types offishing gear is bycatch of non-target species whichmay include other commercial or non-commercial fishand seabirds such as shags and marine mammals.In the Isles of Scilly bycatch is not monitored andthe amount of discards produced by the fishing ofnon-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 of cetaceans are monitored by the CornwallWildlife Trust 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 of 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 oflow currents. It leads to suspension of fine sedimentsand large rocks may be overturned. In areas with littlewater movement near the bottom these impacts onthe micro-topography of an area can accumulate andpersist for months.Migratory speciesWhile fishing effort can be controlled fairly easilywithin the territorial waters of the Isles of Scilly, thepotential for overfishing of migratory species outsidethese waters is high. An example of this is the fact thatlobsters (a site attached species) have a fairly stablepopulation in Scilly whereas crawfish are migratoryand their numbers are in decline, probably due tooverfishing by boats from other EU nations.Shark species are not targeted in Scilly 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 of four main sources ofmarine litter on UK beaches (Beachwatch, MarineConservation Society, 1999) with fishing debrisaccounting for 11.2% of 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.There 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 Scilly 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 of these species due to the risk ofdamaging their gear. Dredging is indiscriminate inIsles of Scilly biodiversity audit Page 82


3.4 Built DevelopmentOverviewAs with many island communities, there is adistinctive feel to the built development pattern. The‘capital’ of the islands is Hugh Town, on St Mary’s,built on a sand bar joining the main island withthe Garrison. The next largest development is OldTown, the original main settlement. Both Hugh Townand Old Town were subject to a 2003 survey by theEnvironment Service of Cornwall County Councilto assist in providing a framework for sustainableregeneration in the area.There are a number of smaller developments on StMary’s, with residential accommodation at Telegraphand Porthloo, but, apart from these areas mostdevelopments are isolated farmsteads.On the off islands, small clusters of buildings show apattern of development in areas most sheltered fromthe predominant winds and where the most fertileland exists. Little new building has taken place onthese islands. The 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 of habitat type where such development mayhave the most detrimental effects.supports proposals that would contribute to thefurther diversification and essential modernisationof 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 ofthe 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 of the highest concentrations in theUK. Funding has also been secured to build a newschool base on St Mary’s.Use of Existing BuildingsIn appropriate circumstances, the Local Plan permitsdevelopment where a proposal would contributeto the sustainability of the islands’ environment,economy or local communities. The Local Plan alsosupports the re-use of existing buildings for theeconomic benefit of the islands providing any proposalis of a sympathetic design.A Design Guide has been prepared to supplementthe Local Plan to ensure that new proposals aresympathetic to the character of the islands andincorporate the principles of sustainability.ManagementLandscaping which is sympathetic to, and integratedwith, the surrounding countryside can minimise thevisual impact of any development and act as a bufferbetween it and wildlife habitats.Major Policies, Schemes and OrganisationsIn view of the exceptional quality of the environmentand the infrastructural constraints facing the islands,the over-arching aim of the Isles of Scilly Local Plan isto keep development to the minimum for sustainingthe islands’ communities. The Local Plan has beensubject to extensive consultation with the communityand key stakeholders, including the Duchy ofCornwall and the Wildlife Trust.Copies of the Isles of Scilly Local Plan are availablefrom the Isles of Scilly Council website.Additionally, in press for publication in Summer2008, is CWT’s Isles of Scilly Bio/GeodiversitySupplementary Planning document. This is anaddendum to the wider Cornwall Planning Guidancedocument published in 2007.IssuesDevelopment PressureThe policies and proposals in the Local Plan aregenerally restrictive. However, it does containpolicies that allow for a limited amount of affordablehousing to meet the needs of the community andThe harbour at Hugh Town, St Mary’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 83


3.5 Transport and AccessOverviewThe Isles of Scilly suffer, as do all island communities,from transport and access issues. Scilly 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.The good links are maintained by the high touristattraction of the islands – this is discussed in Section3.10 of this report. Improved transport links, whilstgood for the economic development of the islands, willpotentially increase tourism and casual visitors whichcould impact on the biodiversity of the islands.Despite these good transport links, the cost of 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 OrganisationsThe Isles of Scilly 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, CornwallCounty Council, Duchy of Cornwall, Penwith DistrictCouncil and the travel operators. These stakeholdershave joined to create the Isles of Scilly TransportStrategy and Route Partnership to seek solutions forthe development, improvement and accessibilityof transport links to the islands. As part of thepartnership funding was secured to improve St Mary’sQuay. In addition, funding has been secured to assistin the refurbishment of the off island quays. All ofthese projects are identified in the Local Plan.IssuesInfrastructure ProjectsMajor projects such as refurbishment of the off 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. There will need to be a levelof 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 of roads to cope with any increase. Trafficlevels on the off-islands are very low and are thereforenot an issue.ManagementThe management of boundary features on roadsidesis a key biodiversity issue. There needs to be lessmanagement to increase their biodiversity potential;these areas can become important semi-natural habitatwhich attracts a wide diversity of plants and animals.Scillonian III in St Mary’s harbour. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 84


3.6 Air & Terrestrial PollutionOverviewPollution can be defined as:The introduction by man into the environmentof substances or energy liable to cause hazardsto human health, harm to living resources andecological systems, damage to structure or amenity, orinterference with legitimate uses of the environment(Holdgate 1979).It can take the form of “point source” pollution e.g.discharge into a watercourse, or “diffuse” pollutionsuch as agricultural run-off. Its impact on biodiversitycan equally be limited in the time or area affected, orcan be spread over a longer period or wider area.The Isles of Scilly 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.The most likely and significant threat to the Isles ofScilly is that of marine pollution, both from a majoraccident at sea or just an accumulation of marine wasteand this is addressed at 3.7.Waste disposal is a major issue for the Isles of Scillyand has been addressed in the Local Plan.Major Policies, Schemes and OrganisationsThere has been a proliferation of environmental,waste and pollution legislation and all of these willbe implemented by the Isles of Scilly Council. As aunitary council it has wider powers than other bodieslooking after a similar area. Additionally, the Councilreplaces the responsibilities of the EnvironmentAgency on the islands.IssuesWaste DisposalAs with all isolated communities, where to disposeof waste is a sensitive issue. Increased landfill willcompromise the integrity of 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 of population.Education/AwarenessContinuing education and awareness of waste andrecycling is being carried out under the auspices of theScilly Waste project.Tresco. Photo: RNAS Culdrose SAR flightIsles of Scilly biodiversity audit Page 85


3.7 Marine PollutionOverviewAbout 80 percent of marine pollution is derivedfrom land-based activities, often entering the marineenvironment through land run-off or direct discharges(DEFRA, 2002). Contaminants become dispersed in themarine environment and are in highest concentrationsclose to the land. The influence of pollution frommainland sources depends on the nature of thecontaminant, many pollutants will not reach Scillyin significant concentrations whereas others such asplastics can travel thousands of kilometres. There arealso sources of 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. They may also combine with otherchemicals (known as a ‘cocktail effect’) with unknownconsequences. Due to the distance from industrialareas and major sources of land based pollutionScilly is likely to have low levels of marine pollution;however this has been little studied or monitored.Scilly is at risk from oil spills or other pollution eventsassociated with shipping accidents. Toxins and soilmay enter the marine environment in run-off waterfrom the land, particularly where farming is practisedvery close to the shore.Major policies, schemes and organisationsThe Isles of Scilly Wildlife Trust is responsible for mostof the Islands’ beaches. The Council for the Isles ofScilly 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 Scilly, at PorthCressa beach (St Mary’s) and Middletown beach (StMartin’s). The Marine Conservation Society hopes tocontinue these events, involving the local communityand visitors, working with the Area of OutstandingNatural Beauty.During stakeholder consultation meetings for the Areaof Outstanding Natural Beauty management plan,concern was expressed about the levels of litter andoil pollution and about the lack of funding for tacklingpollution incidents. Some stakeholders felt that theresponsibilities for responding to acute and chronicpollution problems was unclear (AONB ManagementPlan, 2004).IssuesThe Isles of Scilly have a history of shipwrecks, dueto their many submerged reefs, rocks and banks andthe potential for stormy weather. The threat of futureshipping accidents is ever present. One of the first andlargest oil spills of modern times to affect the Englishcoast occurred on the Seven Stones Reef, 8 kilometreseast of Scilly. The Torrey Canyon oil tanker hit the reefin 1967, spilling 100,000 tonnes of crude oil. Only thedirection of the prevailing wind at the time preventedthis from becoming a major disaster for Scilly, the oilcame ashore on the coast of 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 contentsof the containers were washed up on many of thebeaches. The shipping company’s insurers took noresponsibility for this and the result was that thecouncil had to pay for the clean-up operation. Rollsof polythene film, a total of 3740 miles in lengthand 3 feet wide disintegrated and were distributedin the marine environment. Despite huge effortsby volunteers, less than 1% of this polythene wasever recovered (Smith, 1997). The then Isles of ScillyEnvironmental Trust did much of the work.This demonstrates the potential for highly damagingmarine pollution incidents. Their nature may differdepending on the nature of the cargo and the ability tocontain oil spills. Spillage of 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 often more damaging to the marine life than theoil spill itself. They may involve the use of chemicaldispersants, hot water or pressure washing of theforeshore and widescale trampling.The Isles of Scilly have been awarded an ‘Area to beavoided’ status (an advisory message to merchantskippers) but sea traffic between Scilly and Land’sEnd has greatly increased in recent years and therisk of another incident in the future is high (EnglishHeritage, 2004).The Emergency Planning Department of the Islesof Scilly Council has produced a draft Oil SpillContingency Plan which expands on the NationalContingency Plan from the Maritime and CoastguardAgency (MCA). In the event of an oil spill thegovernment has the responsibility for managing thepollution from 1 mile offshore but the local authoritiesare responsible for shoreline clean up. The nearestbooms for containing oil are kept by the MCA atTruro but other equipment would have to come fromfurther afield. Methods of containing, dispersingand removing the oil are dependent on a number ofenvironmental factors and the nature of the oil itself.Methods such as high pressure washing and use ofIsles of Scilly biodiversity audit Page 86


chemical dispersants will only be used for cleaningthe shore following consultation and advice fromconservation organisations. The 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 of the local authorities who would haveto try to claim for the cost of the clean up from theship’s insurance company.Plastic rubbish from both distant and local sources isdeposited on Scilly’s beaches. This material is verypersistent in the marine environment and can haveunknown effects. Microplastics (tiny fragments ofbroken down plastics) are present in the sands inScilly 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 off can cause problems in the marine environment,disturbing the balance of the ecosystem. In Scillythere is treatment of 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 of nutrient removal. Howeverfor the main centre of 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 off the outfall and solidsand sanitary products have been known to wash intoPorth Cressa beach.For more isolated buildings and on the off-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. Thefinal soakaway often discharges over cliffs or ontobeaches.Agricultural run offFlowers, bulbs and potatoes are the main crops inScilly 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. Therefore run-off 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 fishingoften ends up on beaches, these items are often plasticand highly persistent in the environment. Surveys in2007 showed that fishing debris made a significantcontribution to beach litter and accounted for over30% of all traceable litter on most beaches surveyed inScilly (Beachwatch, Marine Conservation Society).Refuse DisposalIn the past, refuse from the islands was disposedof 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 of 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 off-islands and burnablematerials are incinerated, mostly on St Mary’s. There isno reclamation of heat or power from the incinerationprocess but emissions are checked by the EnvironmentAgency. Through a project called Scilly Waste metaland glass is recycled on St Mary’s and waste reductionmeasures are promoted.AwarenessThe Scilly Waste Project aims to raise awareness aboutrecycling and waste minimisation across all sectors ofsociety. The AONB has been working with the localschools to raise awareness amongst island childrenabout waste awareness with a focus on marine litter.They 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 of 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 Scilly in 2005 and 2007 and the Marine ConservationSociety hopes to continue it there.Isles of Scilly 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 of the wider habitat mosaic. Thisis probably more noticeable on island communitieswhere fresh water is often at a premium.There are no rivers in the Isles of Scilly, 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. The 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. The other inhabitedislands rely on private boreholes supplemented withrainwater collection tanks.The lack of potable water in periods of 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 OrganisationsThe Council for the Isles of Scilly has responsibility forthe water supply and works in close cooperation withboth the Duchy of Cornwall and the Tresco Estate. TheDuchy has commissioned assessments of the watersupply both on St Agnes and St Martin’s where privateboreholes are the major source of water; a funding bidthrough Objective One has been obtained to try andimprove the situation on St Agnes.There are water-level management plans for bothLower & Higher Moors produced by the Council forthe Isles of Scilly.IssuesPollution/Saline IntrusionPollution through agricultural run off is a threat, butnot significant given the lack of rivers and groundwater. Saline intrusion, particularly of the privateboreholes, is of great concern as these are the onlysource of water on the off islands. Some of 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.The catchment on St Mary’s collects run-off 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 of 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 of tourists stay; the building of adesalination plant in 1992 has alleviated the problemto some extent, but it does not produce a surplusfor use on other islands. The 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 of fresh water.Agricultural practices may need to be adapted to takeaccount of these water shortages and extraction ofwater may lead to drier soil conditions which maylead to a change in the biodiversity of terrestrial plantcommunities.Lower Moors on St Mary’s from where some of the drinking water is abstracted. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 88


3.9 Climate Change / Sea LevelRiseOverviewThere 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 of Ice Age andlong warmer periods; indeed there has probably beena warmer period in pre-history than that currentlybeing experienced based on examination of coresamples of soil content. However, there is very strongevidence that the current warming of the planet iscaused by CO2 emissions – an anthropogenic effectwhere the change is not part of the natural cycle ofclimate 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). There 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. The geographical position of the GulfStream may alter and this could particularly affect theIsles of Scilly.Historical Sea Level Rise for Isles of Scilly“Exploration of a Drowned Landscape”, the 1985study of sea level rise by Charles Thomas states thatby 3000BC the islands of St Agnes, Annet and theWestern Rocks had become separated from the largerland mass known as Ennor. The rest of 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 of 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 futureof the islands.Major Policies, Schemes and OrganisationsClimate change is being addressed at a numberof levels from international to local; a number ofmajor 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 ofgovernment policy and the Climate Change Bill 2007will, if ratified, become a defining piece of legislationdesigned to reduce carbon dioxide emissions by 20%by 2050.IssuesResearchThere are a number of differing views as to the causesand effects of climate change; it is an evolving sciencethat polarises opinion. Research will need to becontinued as evidence with respect to climate changedevelops. The species and habitat mix highlightedas of conservation concern in this report will be anevolving tapestry and will need regular and criticalreview.PublicationsThe South West Wildlife Trusts “A Strategy forChange” is a suitable starting point for the assessing ofhow individual trusts can work towards amelioratingthe effects of climate change on biodiversity.Sea level rise and increased storminess due to climate change may hasten coastal erosion. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 89


3.10 TourismOverviewTourism is the mainstay of the Isles of Scilly economyand present day culture; it generates in excess of 85%of the islands’ Gross Domestic Product at about £62million annually. The growth of 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 of visitors to Scilly as the following tableindicates:Year Visitor Numbers2003 123,9592004 125,0762005 117,0322006 104,6822007 104,987Source: Council for the Isles of ScillyThe fall in figures represents a reduction in thenumber of casual day visitors, particularly duringthe poor summers of 2006 and 2007. The number oflonger staying visitors who book ahead has remainedconstant and this reflects the ceiling imposed withlimited accommodation opportunities. The positionof 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 Isles ofScilly 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 of visitors, surveyed by the Islesof Scilly Tourist Board in 2005/06, believe that Scillyshould promote a more environmentally sustainableenvironment.Major Policies, Schemes and OrganisationsThe Isles of Scilly Council, Duchy of Cornwall, TrescoEstates, Cornwall County Council and the variouscarriers are the key organisations. They have combinedto form the “Route Partnership” and the first majoroutcome of this was obtaining funding for technicalinvestigation and appraisal of 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 of all the quays on the off-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 of visitors.The Green Tourism Business Scheme has beenpromoted on Scilly through the AONB and 9 localbusinesses have received awards under this scheme.Scilly has the greatest concentration of members of thisscheme in the UK.IssuesThere are a number of issues where tourism mayimpact on the wider biodiversity:EconomyAny decline in the environmental quality of the islandsthreatens the tourist economy, particularly as manypeople visit the islands for their environmental andscenic qualities.AwarenessThere 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 of tourists the Isles of Scilly can copewith. The traditional ’high’ season has already beenextended into November due to birdwatching, andthe mild climate and wider availability of year roundtransport to the islands may well increase the loading.An initiative called Walk Scilly promoted by the Islesof Scilly Tourist Board also aims to increase visitornumbers during the ‘shoulder’ seasons but has thepotential to increase levels of erosion on footpaths.There needs to be awareness that this increaseshould be managed to minimise the impacts on thebiodiversity of the islands.DevelopmentMost built development is undertaken out of 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 of day visitors which maywell increase as the availability of transport improvesyear round.A scuba diver interacting with an inquisitive seal.Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 90


3.11 Economic DevelopmentOverviewThe speed and breadth of economic developmentis key to any island’s development. This is no lessthe case for the Isles of Scilly 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 of anyfuture built development and a significant increase intourism, both casual day visitors and longer stayingtourists.There are a number of initiatives that will influencethe wider economic development of the islands andthese are inextricably linked to the topics discussedthroughout Section 3.Major Policies, Schemes and OrganisationsThe Isles of Scilly Local Plan (2005)The Local Plan lists the following key factors in theeconomic development of the islands:To promote employment and economic activity byproviding opportunities for businesses to supportviable communities. Proposals based on the existingeconomic base of tourism, agriculture and fishing,as well as the distinctiveness of the islands, will besupported in the following cases:· Where such development contributes to thefurther diversification and essentialmodernisation of the islands’ economy· Where it demonstrably improves the qualityof existing tourist accommodation, including thatof managed camping sites, or potentially extendsthe length of the tourist season· Where there is a change of use for a larger hotelor guesthouse (in excess of 6 bed spaces) toanother form of tourist accommodation whichdoes not create an imbalance of accommodationavailable to tourists· Where development provides either a hostel orbunkhouse linked to environmentally oreducationally based activities· Where self contained tourist accommodation isprovided as part of a farm holding and isnecessarily related to the farm’s continuedviability and overall land managementThe Isles of Scilly 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 of the islands.Boats to the off-islands run from the quay on St Mary’s. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 91


Key Strategic Plans relating to the Isles of ScillyThe following key pieces of legislation/strategieswill have an impact on both the islands’ economicdevelopment as well as the wider support ofbiodiversity:· Power of Place (English Heritage) – the historicenvironment is a vital resource which playsan indispensable role in the sustainable long termrenewal of the islands.· The Historic Environment: A Force for OurFuture (DCMS) – looks to the full and totalembracing of the historic environment usingit to the benefit of 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 ofcommunity.· Draft Regional Spatial Strategy for the SouthWest 2006-2026 (Jun 06) – Policy SR42 dealsspecifically with the Isles of Scilly and statesthat the Local development Document should,inter alia, diversify the local economy (whichis heavily dependant on tourism) and protect theenvironment.· Isles of Scilly Landscape Assessment – raiseawareness of the AONB and guide policy makersfor the area.· Isles of Scilly AONB Management Plan– recognised as a centre of 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 : Isles of Scilly Investment Plan,The Objective One Integrated Area Plan – toimprove the economic base of the Isles of Scillythrough appropriate sustainable developmentwhilst protecting and enhancing the uniquenature of the Scillonian environment.· Isles of Scilly Transport Strategy “Moving On”– develop a strategy for sustainable transport forthe islands.that tourism is developed in a positive andsustainable way.· Isles of Scilly Wildlife Trusts ManagementPlans – to set out the best management practicesfor the land leased by the Trust in order toachieve key conservation objectives.The Cornwall and Isles of Scilly Economic Forum haspublished the Economic Strategy for Cornwall andthe Isles of Scilly 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 of EUfunding from 2007 onwards. This document can beviewed at www.economicforum.org.ukIssuesCoherencyThe plethora of legislation and strategies in place needto have linkage in objectives in order to ensure:· There is no overlap in use of resources· There is no dichotomy in the overall objectives· Confusion is not created with the large numberof 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.The Isles of Scilly’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 ofScillyOpportunitiesThe potential for economic development strategies andprogrammes to have a positive impact on biodiversityneeds to be fully explored and should remain at theforefront of any future planning or proposals.· Isles of Scilly Tourism Strategy – to achievesynergy and coherency in a marketing policy soIsles of Scilly biodiversity audit Page 92


4Priorities for BiodiversityConservationThe diversity of the Isles of Scilly’s habitats andspecies provides an essential element of the islandscharacter. Their current status should be maintainedor enhanced so that future generations can benefitfrom both the environmental quality and economicopportunities on offer.In order to achieve the best conservation andenhancement of the Isles of Scilly 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 ofrecords held at ERCCIS has allowed the Isles of Scilly’sspecies and habitats to be assessed for priority actionto the best of current knowledge.Priorities are decided using specific criteria, to includespecies or habitats which are threatened, decliningor rare or for which the Isles of Scilly have a specialresponsibility.SpeciesSpecies have been added to the priority list if they arepresent in Scilly (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 Scilly· Or on the advice of species experts293 species have been prioritised.HabitatsHabitats on the priority list are either· National BAP habitats· Or have been added on the advice of expertsbecause they are important for Scilly but donot fit into the BAP habitat categories.18 habitats have been prioritised.Some of the species and habitats are priorities forfurther survey work, and their retention on thepriority lists will depend upon the findings of furtherfield surveys or studies.The following tables summarise the priority species(Section 4.1) and priority habitats (section 4.2)Botanists on holiday. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 93


4.1 SpeciesThis Biodiversity Audit identifies species in need ofsome level of conservation action. Where possibleconservation of 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 Scillythrough 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 Isles of Scilly priority list have beenselected because they are nationally important orimportant to Scilly.Within the table information is provided, whereknown, on local decline, local rarity and local threatsto help assess priority. Details of 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.There are 293 species on the Isles of Scilly 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 ScillySpecies which have very fewknown sites or are very littlerecorded in Scilly.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 Biodiversity 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 Biodiversity Action Plan habitat in Scilly.RecommendationsRecommendation numbers 1-6 are therecommendations found in Section 5.The following species list is not intended to becomprehensive and will reflect the level of 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.Isles of Scilly 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 Scillyin 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 toScilly 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 England4,1Isles of Scilly 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 1,31,31,3Isles of Scilly 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 of 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 2Isles of Scilly biodiversity audit Page 97


Ornithopus pinnatus Orange Birdsfoot RDB Static Uncommon Threatened Yes Sandy ground and heathlandEndemic toScilly andCornwall 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 toScilly andCornwall 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 ofcliffs 2,3Isles of Scilly 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 4,1Isles of Scilly 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 of 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 4,1Isles of Scilly 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 4,1Isles of Scilly 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 wallsScilly is astronghold2,32,32,3Isles of Scilly 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 of habitats. Larvalfoodplant: herbaceous plantsApamea remissa Larval foodplant: a range ofDusky 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 The Crescent BAP Rare Yes Fens and marshy ground. Larvalfoodplant: marshy plants such asyellow flag Iris pseudacorusScilly is astrongholdEndemic toScillyScilly 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-speciesIsles of Scilly 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 millefoliumScilly 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 of woodland and moreopen areas. Larval foodplant:willowherbs Epilobium sppEumichtis licheneascilloneaFeathered Ranunculus Common Yes Coastal areas. Larval foodplant:low plantsHoplodrina blanda The 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 ofDot Moth BAP Rare Waste ground and gardens.plantsMelanchra pisi Broom Moth BAP Uncommon Yes Open woodland and heathland.Larval foodplant: broom Cytisusscoparius and othersIsles of Scilly 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 andThe Cinnabar BAP Common Grasslands. Larval foodplant:othersXanthia icteritia The Sallow BAP Rare Yes Damp woodland, marsh andheathland. Larval foodplant:sallow and herbaceous plantsXanthorhoe ferrugataDark-barred TwinspotCarpetBAP Uncommon Widespread. Larval foodplant: avariety of 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 CommentsRecommendationIsles of Scilly 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 Scilly oneof 4 knownsites inEnglandAtagema gibba A sea slug NR Steep rock faces, 8-15m depth Onlyknown fromCornwall &Scilly 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 of 100m Only 4known sitesin England4,14,1Isles of Scilly biodiversity audit Page 106


RecommendationRecommendationRecommendationAmmodytes marinus Lesser Sand Eel BAP Common Yes Subtidal soft 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 CommentsIsles of Scilly 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 4Isles of Scilly 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 CommentsIsles of Scilly 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 222222Isles of Scilly 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 offshoreislands 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 Freshwater2Isles of Scilly 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 2,3Isles of Scilly 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 4,2Isles of Scilly biodiversity audit Page 113


4.2 HabitatsThe conservation of 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 of other species. A numberof habitats have been identified as priorities forthe Isles of Scilly and most appear as national BAPhabitats on the recently revised 2007 list.species. A number of habitats have been idof Scilly and most appear as national BAP h2007 list.The stone hedges in Scilly are unique and notrepresented Prioritisation under the BAP of system. Habitats Likewise on the Isles of Scillowland unimproved grassland (other than the acidgrassland) The does Isles not match of Scilly any cover of the BAP a very habitat small area andcategories,audityet isalsoveryidentifiesimportant2toother habitatimportantmosaichabitats win Scilly.The followingThehabitatstonelisthedgesreflectsintheScillycurrentareleveluniqueofand notknowledge system. and understanding Likewise the of habitats lowland in unimproved Scilly. grasIt must be grassland) considered a does “live” not document match subject any of to the BAP habchange and important amendment. to the habitat mosaic in Scilly.Prioritisation of Habitats on the Isles of ScillyPriority ListThe Isles of Scilly 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 ScillydationsLowland Dry Present: prob. Stable 3Acid Grassland small (


5Recommendationsfor ActionThe role of this Biodiversity Audit is to highlightthe priorities for biodiversity conservation in theIsles of Scilly and make recommendations forimmediate action. The following recommendationsare proposals for action based upon the prioritiesidentified in Section 4. Where possible, theproduction and implementation of action plans willutilise existing mechanisms of delivery.These recommendations are for biodiversityconservation at a local level; many of 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.The production of these recommendations was basedon experience from Cornwall’s Biodiversity Initiativeand on the latest ideas from the national BiodiversityReporting and Information Group about deliverymechanisms.Public AwarenessExperience from Cornwall’s Biodiversity 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. Therefore 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 ofpublic awareness.Clearly it is crucial that the public are kept informedand engaged with the work stemming from thisBiodiversity Audit and this should be consideredthroughout the planning of 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 of theBiodiversity Audit on the local radio station.It must be stressed that local ownership andunderstanding of 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 Scilly and other key stakeholderssuch as businesses, councils etc. Outreach work mustidentify and target each group. Many visitors cometo Scilly because of the natural environment and itshould be possible to successfully conduct outreach inthe short time they may be visiting.Concepts such as the use of flagship species canbe useful and Scilly has a number of 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 Biodiversity Audit.Isles of Scilly biodiversity audit Page 115Corn marigold Chrysanthemum segetum. Photo: Rosemary Parslow


RecommendationsRecommendation 1 – SurveyPromote and instigate survey work for those speciesand habitats on the Isles of Scilly priority lists inSection 4 which need further research to establish theirlocal conservation needs and status.The 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 ofsignificance to Scilly. 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 of many of the priority habitats is stillneeded in order to measure changes in the extent ofhabitats and for planning habitat management.Recommendation 2 – Monitor and ResearchSupport and instigate monitoring and research ofspecies and habitats on the Isles of Scilly priority list.Monitoring of priority habitats and species isrecommended particularly where local threats havebeen identified. There 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 of priority speciesand habitats should be encouraged. This includesassisting where possible towards the completion ofthe All Taxon Biodiversity Inventory for the marinelife of the Isles of Scilly. The production of a ScillyRare Plants Register similar to that being producedfor Cornwall is recommended in order to provide amore complete picture of the rare and special florain Scilly. It is further recommended that a satellite ofthe Environmental Records Centre for Cornwall andthe Isles of Scilly is established on Scilly to supportmonitoring efforts and promote biological recording ingeneral.actions outlined in this report and will make asignificant contribution to the achievement of many ofthe other key recommendations.Recommendation 4 – Marine Protected AreaWork towards the inclusion of the Isles of Scilly ina South West or National Marine Protected Areanetwork.Marine Protected Areas are a simple way of managingresource use in the marine environment, providingprotection for the entire ecosystem. Along with othermeasures a network of MPAs can reduce pressure andpromote recovery of 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 ofseparate Action and Implementation Plans. Experiencefrom Cornwall’s Biodiversity Initiative has shownthat the number of 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 theIsles of Scilly as a focus for delivering biodiversityaction on Scilly.The Conservation Advisory Group should takeownership of this Biodiversity Audit and beresponsible for its delivery. Resources should besought to ensure that these recommendations canbe taken forward into programmes of work andthat their actions can be achieved. There may bea need to produce a further volume which buildson this Biodiversity Audit to detail how theserecommendations can be implemented. Best practiceshould be shared between this group and theequivalent group in Cornwall.Recommendation 3 – Manage IoSWT land holdingsImplement, maintain and monitor the work plansoutlined in the Management Plans for Isles of ScillyWildlife Trust holdings produced in conjunction withthis report.Management Plans for all the Isles of Scilly WildlifeTrust holdings were produced in parallel with thisreport. It is strongly recommended that these plans beimplemented as they support the wider biodiversityIsles of Scilly 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 bedBiodiversity Action Plan (BAP) – The 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 of Species ActionPlans, Habitat Action Plans and Local BiodiversityAction Plans with targeted actions.Biotope - an area of uniform environmental conditionsproviding a living place for a specific assemblage ofplants and animals.Circa-littoral – 40-65m depth zoneDemersal – the area just above the sea bedDiadromous – fish which spend part of their lifecyclein freshwater and part in the seaDraw down zone – the area on the margins of 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 ofplant 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 – of or on the shoreLusitanian species – species whose geographicalrange includes the Iberian Peninsula, particularlythose with a stronghold in that area.Meiofauna – animals of microscopic size living insediments, marine meiofauna is found from the shoreto the deep sea.Mesotrophic – an environment such as a bodyof water with intermediate levels of productivity(between oligotrophic and eutrophic).NS (Nationally Scarce) – a species recorded from 16 to100 10 km squares of the British National Grid.Oligotrophic – an environment that offers little tosustain life, such as a body of water with low nutrientlevels.Pelagic – associated with the open seaPlankton – small, free floating organisms of the sea orother aquatic environmentClose up of sea urchin spines and tube feet. Photo: Malcolm NimmoIsles of Scilly biodiversity audit Page 117


Ram – also called head or rab, cement-like materialformed by breakdown of granite fragments shatteredby glaciation.RDB (Red Data Book) – RDBs contain lists of 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 of the continental shelfSubtidal – below the level of the lowest tideTerricolous – living on or in the groundAcronymsAoNB –BAP –BSBI –CISFBR –CWT –DEFRA –NANS –NR –NVC –IoSWT –IoS –RDB –SAC –SSSI –Area of Outstanding Natural BeautyBiodiversity Action PlanBotanical Society of the British IslesCornwall and Isles of Scilly Federationof Biological RecordersCornwall Wildlife TrustDepartment for Environment, Food andRural AffairsNatural EnglandNationally ScarceNationally RareNational Vegetation ClassificationIsles of Scilly Wildlife TrustIsles of ScillyRed data bookSpecial Area of ConservationSite of Special Scientific InterestGugh. Photo: Rosemary ParslowIsles of Scilly biodiversity audit Page 118


Bibliography7Aprahamian M and Robson CF (1996) Chapter 5.8 Fish:Salmon, sea trout and eels. In: Barne et al (1996)Bamber R N, Evans N J, Chimonides P J, Williams B A P(2001) Investigations into the hydrology, flora and faunaof the pool of Bryher, Isles of Scilly. Natural HistoryMuseum Consulting, Report No. ECM 759101Barne JH, Robson CF, Kaznowska SS, Davidson NC,Doody JP and Buck AL (Eds) Coasts and Seas of the UnitedKingdom, Region 11. The Western Approaches (FalmouthBay to Kenfig). Peterborough, Joint Nature ConservationCommittee.Beavis IC (2007). Hymenoptra and Diptera of Scilly– 2006 update. Isles of Scilly bird and natural history review2006:147-149. ISBGBishop G (1985) Study of Echinus esculentus populationsin the Isles of Scilly, October 1984, Report to NCCBratton JH (1991) British Red Data Books: 3 Invertebratesother than insects. JNCCBristowe WS (1929). The spiders of the Scilly Isles.Proceedings of the Zoological society of London, 149-164Bristowe WS (1935). Further notes on the spiders of theScilly Isles. Proceedings of the Zoological society of London,2109-232British Geological Survey (1978) Isles of Scilly, Sheet357/360, 1:50,000 Series. NERCBrodie J, John D M, Tittley I, Holmes MJ and WilliamsonDB (2007) Important Plant Areas for algae: a provisionalreview of sites and areas of importance for algae in theUnited Kingdom. Plantlife International, Salisbury, UK.Brown AE, Burn AJ, Hopkins JJ and Way SF (1997).The Habitats Directive: Selection of Special Areas ofConservation in the UK. JNCC Report No 270Cameron RAD (2006) Slugs and Snails in Scilly. Isles ofScilly Bird and Natural History Review 2005. Isles of ScillyBird Group.CBRU (1995) The Isles of Scilly. NVC Mapping ofPeninnis Head, The Plains & Great Bay and Gugh SSSIs.A Preliminary report to EN Cornwall OfficeCheffings CM and Farrell L (Eds) (2005) The VascularPlant Red data List for Great Britain. Species Status 7: 1-116.JNCC, PeterboroughCleator B, Nunney R and Mackenzie G (1993) Coral CayConservation Sub Aqua Club 1992 expedition to the Islesof Scilly. Report to English NatureClitherow J and Covey R (ND) Natural Area Profile – Islesof Scilly. English NatureConnor DW, Allen JH, Golding N, Howell KL,Lieberknecht LM, O’Northen K and Reker JB (2004)The Marine Habitat Classification for Britain andIreland Version 04.05 JNCC, Peterborough ISBN 1861 07561 8 [online] Available at: www.jncc.gov.uk/MarineHabitatClassification [accessed 20 January 2008]Connor DW, Breen J, Champion A, Gilliland PM,Huggett D, Johnston C, Laffoley D d’A, Lieberknecht L,Lumb C, Ramsay K, and Shardlow M (2002). Rationaleand criteria for the identification of nationally importantmarine nature conservation features and areas in the UK.Version 02.11. Peterborough, Joint Nature ConservationCommittee (on behalf of the statutory nature conservationagencies and Wildlife and Countryside Link) for theDefra Working Group on the Review of Marine NatureConservation [online] Available from: http://www.jncc.gov.uk/PDF/sg341.pdf [accessed 12 December 2007]Photo: Angie GallIsles of Scilly biodiversity audit Page 119


Cook KJ, Enderson A and Reid TJ (1999) Report on theCoral Cay Conservation SubAqua Club 1998 Expeditionto the Isles of Scilly, Report to English NatureCook KJ (1999) Report on the Coral Cay ConservationSubAqua Club 1999 Expedition to the Isles of Scilly,Report to English NatureCook, KJ, Hinton, C and Reid, TJ (2001) Report on theCoral Cay Conservation SubAqua Club 2000 Expeditionto the Isles of Scilly, Report to English NatureCornwall Biodiversity Initiative (1997) Cornwall’sBiodiversity Volume 1: Audit and Priorities. EnvironmentalRecords Centre for Cornwall and the Isles of Scilly,Cornwall Wildlife Trust, TruroCornwall Biodiversity Initiative (2004) Cornwall’sBiodiversity Volume 3: Action Plans. EnvironmentalRecords Centre for Cornwall and the Isles of Scilly.Environmental Records Centre for Cornwall and the Islesof Scilly, Cornwall Wildlife Trust, TruroCouncil of the Isles of Scilly, IoS ET, EN (1998) WaterLevel Management Plan: Higher Moors Site of SpecialScientific InterestCouncil of the Isles of Scilly, IoS ET, EN (1998) WaterLevel Management Plan: Lower Moors Site of SpecialScientific InterestCouncil of the Isles of Scilly (2003) St Agnes, Isles ofScilly: Drinking Water and Waste Water StudyCouncil of the Isles of Scilly (2004) A Heritage and CulturalStrategy for the Isles of Scilly Isles of Scilly Council ReportCouncil of the Isles of Scilly (2005) The Isles of Scilly LocalPlan: A 2020 Vision Isles of Scilly Council ReportDargie TCD (1996) Chapter 3.1 Cliffs and cliff-top vegetation.In: Barne JH et al.Dargie, T.C.D. (1996) Chapter 3.2 Sand dunes. In: Barne,J.H. et al.Davies JL (1956) The grey seals at the Isles of Scilly.Proceedings of the Zoological Society of London 127: 161-166Dipper F (1981) Sublittoral survey of the Scilly Isles andS. Cornwall. Report to the Nature Conservancy Council fromthe Underwater Conservation SocietyDuck CD (1996) Chapter 5.14 Seals. In: Barne JH et alEdwards B (2002) The current status of Heterodermialeucomela (L0 Poelt) on the Isles of Scilly. Report n. 193.Plantlife/English NatureEvans PGH (1996) Chapter 5.15 Whales, dolphins andporpoises. In: Barne JH et alEnglish Nature (2006) Natural Area Profile 113: Isles ofScillyEnglish Nature (2000) Isles of Scilly European MarineSite. English Nature’s advice given under Regulation33 (2) of the Conservation (Natural Habitats &c.)Regulations 1994English Nature (1994) Marine Annex Types – furtherinformation. Peterborough: English NatureEnglish Nature (1994) Important areas for marine wildlifearound England. Peterborough, English NatureEnglish Nature, Site Objective Statements and citationsheets for SSSIs, Devon & Cornwall. Unpublished report toEnglish NatureERCCIS database. Cornwall Wildlife Trust, Truro.Faubel and Warwick R (2005) The Marine Flora andFauna of the Isles of Scilly. Free-living plathelminthes(Turbellaria). Journal of Natural History 39(1): 1–45Flood, RL, Hudson, N and Thomas, B (2007) EsentialGuide to Birds of the Isles of Scilly. Booth, PenrynFord E B (1975) Ecological genetics. Chapman & Hall,LondonFoster-Smith R (1990) A boulder survey in the Isles ofScilly. A report to the Nature Conservancy CouncilFowler SL (1990) Sub-littoral monitoring in the Islesof Scilly 1987 and 1988. Report to NCC from the NatureConservation Bureau LtdFowler SL (1992). Marine monitoring in the Isles of Scilly1991. English Nature Research Report No.9 from NatureConservation Bureau LtdGainey PA (1997) Tunicata and Cephalochordata In:Spalding A (Ed) (1997) Red Data Book for Cornwall and theIsles of Scilly. CISFBR, Croceago PressGarrick-Maidment N (2007) British Seahorse Survey 2007.The Seahorse TrustGoodwin CE and Picton BE (2007) The red blennyParablennius ruber in the British Isles, with notes on fieldidentification characteristics and ecology. Journal of theMarine Biological Association of the U.K. 87(5): 1309-1313Graham Moss Associates (1984) The Isles of Scilly,Comprehensive Land Use and Community DevelopmentProject. London & BristolGuiry MD and Maggs CA (1982) The morphology andlife history of Dermocorynus montagnei Crouan frat.(Halymeniaceae; Rhodophyta) from Ireland. Br. phycol. J.17: 215-228.Haes ECM (2004). Orthopteroid insects of Cornwall and theIsles of Scilly: an updated provisional atlas. CISFBR, TruroIsles of Scilly biodiversity audit Page 120


Harris T (1972) The Marine Flora and Fauna of the Isles ofScilly: Polychaeta. Journal of Natural History 6, 93-117Harvey LA (1969) The marine flora and fauna of the Islesof Scilly: the islands and their ecology. Journal of NaturalHistory 3: 3-18Hayward PJ (1971) The Marine Flora and Fauna of theIsles of Scilly Bryozoa and Entoprocta. Journal of NaturalHistory 5: 481-489Herdson D (2001) Slipper Lobster Scyllarus arctus. Isles ofScilly Bird and Natural History Review 2001. Isles of ScillyBird Group.Hiscock K and Smirthwaite J (2005) Marine Life TopicNote on Marine Biodiversity. Journal of the MarineBiological Association of the United KingdomHiscock K (1984) Rocky Shore Surveys of the Isles ofScilly. March 27th to April 1st 1983 and July 7th to 15th1983. Volume 1. Nature Conservancy Council, Report No509 (Contractor: Field Studies Council Oil PollutionResearch Unit, Pembroke)Hiscock K (1984) Sublittoral Survey of the Isles of Scilly.July 2 to 16 1983. Volume 1. Survey Report. NatureConservancy Council, CSD Report, No. 529. (Contractor:Field Studies Council Oil Pollution Research Unit,Pembroke)Hiscock K (1985) Littoral and sublittoral monitoring inthe Isles of Scilly 1984. Report to the Nature ConservancyCouncil from the Field Studies CouncilHiscock K (1986) A brief account of the algal flora ofZostera marina beds in the Isles of Scilly In: Irving 1987Hocking S and Tompsett P (2002) The location andConservation of Eelgrass Beds in Cornwall and the Islesof Scilly. Vols.I&2. Project Series No. 5. ERCCIS, CornwallWildlife Trust, TruroHoldgate M W (1979) A Perspective of EnvironmentalPollution Cambridge University Press, CambridgeHolme NA (1983) Report on certain sediment shores inthe Isles of Scilly. Nature Conservation Council TechnicalReport. Marine Biological Association, Plymouth.Holyoak G (2003) Recording land and freshwaterMollusca on the Isles of Scilly, April 2003. Mollusc World3: 20-21Horridge GA (1951) Occurrence of Asparagopsis armataHarv. on the Scilly Isles. Nature 167, 732-733Hummon WD and Warwick RM (1990) The Marine Floraand Fauna of the Isles of Scilly- Gastrotricha. Journal ofNatural History 24, 519-525Irving R (1987) Sublittoral Monitoring in the Isles of Scillyin 1985 and 1986. Nature Conservancy Council CSDreport 823Isles of Scilly Museum Association (1967) Fish around theIsles of Scilly. Isles of Scilly museum publication No.1Isles of Scilly Area of Outstanding Natural BeautyManagement Plan, 2004-2009, The Countryside Agency.Isles of Scilly Ramsar site designation citation (2001). Islesof Scilly listing as a wetland of international importanceunder the Convention of Wetlands of InternationalImportance, especially a waterfowl habitat (the ‘Ramsarconvention’). English NatureIsles of Scilly SPA classification citation (2001). Isles ofScilly classification as a Special Protection Area (SPA)under the EC Birds Directive (79/409/EEC). EnglishNatureJohns C, Larn R and Tapper BP (2004) Rapid CoastalZone Assessment for the Isles of Scilly. A report for EnglishHeritage. Report No: 2004R030Jones L A, Irving R, Cork M, Coyle MD, Evans D,Gilliland PM and Murray AR. (No date) South WesternPeninsula Marine Natural Area Profile: A contributionto regional planning and management of the seas aroundEngland. Peterborough: English Nature.Kendall MA, Widdicombe S, Davey JT, Somerfield PJ,Austen MCV and Warwick RM (1996) The biogeographyof islands: preliminary results from a comparative studyof the Isles of Scilly and Cornwall. Journal of the MarineBiological Association of the United Kingdom 76, 219-222King PE (1972) The Marine Flora and Fauna of the Isles ofScilly: Pycnogonida. Journal of Natural History 6, 621-624Lambert R (2001) Grey seals on Scilly. Isles of Scilly Birdand Natural History ReviewLeach SJ, Page CN, Peytourea Y & Sanford MN(Eds)(2006) Botanic Links with the Atlantic Arc,proceedings of an Anglo-Hiberno-french meetingarranged by the Botanical Society of the British Isles 8-12May 2003. English Nature & BSBILight JM and Kileen IJ (2001) Survey to elucidate thedistribution of the lagoon snail Paludinella littorina inEngland. English Nature Research Reports number 436Lousley JE (1971) The Flora of the Isles of Scilly. NewtonAbbot.Mackenzie G and Irving R (1996) Report on the Coral CayConservation SubAqua Club 1996 Expedition to the Islesof Scilly, Report to English NatureMackenzie G, Irving R and Gibb J (1995) Report on theCoral Cay Conservation SubAqua Club 1995 Expeditionto the Isles of Scilly, Report to English NatureIsles of Scilly biodiversity audit Page 121


Mackenzie G, Rikards K and Wilson P (1994) Reporton the Coral Cay Conservation SubAqua Club 1994Expedition to the Isles of Scilly, Report to English NatureMaggs CA and Guiry MD (1985) Life historyand reproduction of Schmitzia hiscockiana sp. nov.(Rhodophyta, Gigartinales). Phycologia 24: 297-310.Maggs CA and Guiry MD (1986) An Atlantic populationof Pikea californica (Dumontiaceae: Rhodophyta). Journal ofPhycology 21: 757-762Makings P (1987) The Marine Flora and Fauna of the Islesof Scilly: Mysidacea. Journal of Natural History 21, 757-762Manuel RM (1988) British Anthozoa. The Linnaean Societyof London and the Estuarine and Brackish-water SciencesAssociation.Martin A (2001) Cetaceans in Scillonian waters. Isles ofScilly Bird and Natural History Review 2000Morgan VM (1996) Chapter 5.2 Flowering plants andferns. In: Barne, J.H. et al. (Eds)Moy F & Stålnacke P (eds) (2007). Barkved, Kaste,de Wit, Magnusson, Sørensen, Iden, Hygen,Harstveit, Hackett, Albretsen, Deelstra, 5 Steen,Pettersson. Sukkertareprosjektet Analyse av klima- ogmiljøovervåkingsdata med betydning for sukkertare.Sugar Kelp Project: Analyses of climate andenvironmental data with relevance for sugar kelp. TA-2279/2007, 210p. sft.no (in Norwegian)Munro C and Nunny R (1998) Isles of Scilly subtidalhabitat and biotope mapping survey. Peterborough,English Nature Research Report No 276Natural England, Isles of Scilly Natural Area Profile[online]. Available at: http://www.english-nature.gov.uk/science/natural/profiles/naProfile113.pdfNeale JW (1970) The Marine Flora and Fauna of the Islesof Scilly: Ostracoda. Journal of Natural History 4: 399-411Nichols and Harris T (1982) A survey of the low tideflats of the Isles of Scilly. Unpublished Report to the NatureConservancy Council from Exeter UniversityParslow R (2007) The Isles of Scilly. Collins, LondonParslow R (2002) Management Plan for the Isles of Scilly.Unpublished document for IOSWTParslow R (1996) Shore Dock Rumex rupestris Le Gallin the Isles of Scilly, Species Recovery Programme,Unpublished report to English NaturePaton JA and Holyoak DT (2005) The bryophyte flora of theIsles of Scilly. Cornwall Wildlife Trust, Allet, TruroPawson MG and Robson CF (1996) Chapter 5.7 Fish:exploited sea fish In: Barne JH et alPenhallurick R D (1982) Turtles of Cornwall, Devon andthe Isles of Scilly, DyllansowPengwellaPotts G and Swaby S (1995) Species Recovery Project- The Giant Goby in the SouthWest of England. Report toEnglish Nature, Marine Biological Association PlymouthRaines P, Nunney R and Cleator B (1994) Coral CayConservation Sub Aqua Club 1993 expedition to the Islesof Scilly. Report to English Nature.Randall RE (1996) Chapter 3.3 Vegetated shinglestructures and shorelines. In: Barne, J.H. et al.Robins MW (1969) The Marine Flora and Fauna of theIsles of Scilly: Cnidaria and Ctenophora. Journal of NaturalHistory 3: 329-343Robinson, P. (2003) The Birds of the Isles of Scilly.Christopher Helm, LondonRodwell JS (Ed) (1991) British Plant Communities, Vol 1.Woodlands & Scrub. Cambridge University PressRodwell JS (Ed) (1992) British Plant Communities Vol. 3.Grassland & Montane Communities. Cambridge UniversityPressRodwell JS (Ed) (1992) British Plant Communities Vol. 2,Mires and heaths. Cambridge University PressRodwell JS (Ed) (1994) British Plant Communities Vol.4. Aquatic communities and tall-herb fens. CambridgeUniversity PressRodwell JS (Ed) (2000) British Plant Communities, Volume5. Maritime communities and vegetation of open habitats.Cambridge University PressRostron DM (1988) Animal communities from sublittoralsediments in the Isles of Scilly. Volume I. Survey report tothe Nature Conservancy CouncilRostron DM (1983) Animal communities from sublittoralsediments in the Isles of Scilly. Survey report to the NatureConservancy Council from the Field Studies CouncilRowe F W E (1972) The Marine Flora and Fauna of theIsles of Scilly: Enteropneusta, Ascidiacea, Thaliacea,Larvacea and Cephalochordata. Journal of Natural History6, 207-213Rowe F W E (1971) The Marine Flora and Fauna of theIsles of Scilly: Echinodermata, Journal of Natural History 5,233-238Senz W (1993) New Nemerteans from Scilly Islands(Great Britain). Ann. Naturhist. Mus. Wien 94/95, 147-166Smart RWJ and Cooke AH (1885) The marine shells ofIsles of Scilly biodiversity audit Page 122


Scilly, Journal of Conchology 4, 285-302Smith FHN (1997) The moths and butterflies of Cornwall andthe Isles of Scilly. Gem Publishing, WallingfordSmith NA (1997) The environmental impact of the MVCita on the foreshore of Porth Hellick Isles of Scilly. TruroCollegeSmith S and Gault FI (1983) Fauna of some shores of theIsles of Scilly with emphasis on the Mollusca, Report to theNature Conservancy CouncilSouthward EC and Campbell AC (2006). Echinoderms:keys and notes for the identification of British species.Synopses of the British fauna (new series), 56. Field StudiesCouncil: Shrewsbury, UK. ISBN 1-85153-269-2. 272 pp.Spalding A (Ed) (1997) Red Data Book for Cornwall and theIsles of Scilly. Croceago Press, Praze-an-Beeble.Stace C (1995) New Flora of The British Isles. Cambridge:Cambridge University PressStewart A, Pearman DA and Preston CD (1994) ScarcePlants in Britain. Peterborough: Joint Nature ConservationCommitteeSwinbank A and Marsh J S (1987) Prospects for Farming onthe Isles of Scilly Department of Agricultural Economicsand Management, University of ReadingSWWT (2007) A Strategy for Change: A framework forassessing the future role of the SW Wildlife Trusts inameliorating the effects of climate change on biodiversitySWWT/SW ObservatoryThurston MH (1970) The marine flora and fauna of theIsles of Scilly: Crustacea, Eucarida. Journal of NaturalHistory 4: 239-248Valentin R (1909) Additional notes on the fauna of theScilly Isles. Journal of the Institute of Cornwall Vol 17, 351-358Warwick RM (2004) Monitoring Intertidal Sandflats ofthe Isles of Scilly Special Area of Conservation. A Surveyof infaunal organisms of St Martins Sedimentary Shore,October 2004.Warwick (2005) An All Taxon Biodiversity Inventory(ATBI) for the Isles of Scilly: Progress Report. PorcupineMarine Natural History Society Newsletter No.18Warwick RM and Coles JW (1977) The marine flora andfauna of the Isles of Scilly. Free-living Nematoda. Journalof Natural History 11. 393-407Warwick RM, Emblow C, Feral JP, HummelH, VanAvesaath P, Haip C (2003) BIOMARE –Implementation and networking of large scale long-termmarine biodiversity research in Europe. N100-CEME, TheNetherlandsWells JBJ (1970) The Marine Flora and Fauna of the Islesof Scilly Crustacea: Copepoda: Harpacticoida Journal ofNatural History 4, 255-268Westcott S (1993) Seal Summer 1991: Studying the greyseal of Devon and Cornwall. Zoological Cornwall and theIsles of Scilly 2: CBRUWhittaker P (2001) Why tag sharks? Isles of Scilly Bird andNatural History Review 2001. Isles of Scilly Bird Group.Woodworth P L (1987) Trends in UK Mean Sea LevelMarine Geodesy Vol 11, pp 57-58Young B (1998) Mapping Zostera beds in Special Areas ofConservation by Aerial Photography, BKS SurveysThomas C (1985) Exploration of a drowned Landscape– Archaeology and History of the Isles of Scilly. Batsford,LondonTurk SM (1991) Check list of Scillonian marine mollusca.Isles of Scilly museum publication 16Turk SM (1999) Cetaceans stranded on Scillonian Shores.Isles of Scilly bird report 1999:118-121Turk SM and Seaward DR (1997) The marine flora andfauna of the Isles of Scilly: Mollusca. Journal of NaturalHistory 31: 555-633UK Biodiversity Group Tranche 2 Action Plans - VolumeV: Maritime species and habitats (October 1999, Tranche2, Vol V, p149UK Steering Group Biodiversity (1995) The UK SteeringGroup Report. Volume 1: Meeting the Rio Challenge HMSO,LondonIsles of Scilly biodiversity audit Page 123


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