Securing Biodiversity in Breckland - European Commission

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influenced by seasonal water tables and damp grassland, while undrained intact peat can supportfen communities.In the headwaters and tributaries of the Little Ouse, Lark, Wissey and Thet spring-fed valley-headfens have developed on chalky nutrient poor water that percolates upward through thin peat layers(Rothera 1989). Fen exists in a number of sites including at Great Cressingham Fen, ThompsonCommon and Gooderstone Fen in Norfolk and Market Weston Fen in Suffolk which also has sawsedge Cladium mariscus, as does Hopton Fen nearby. Fen with saw sedge Cladium mariscus alsoexists at Talent’s Fen on Foulden Common and at Swangey Fen on the edge of the NationalCharacter Area.Organic peat occurs over most of the river valley floodplains, reaching 2-3 metres depth in thecentre of larger valleys, but is generally drained and humified to a eutrophic state (Corbett, 1973).Little of the valley fen resource remains, though areas do exist along the River Little Ouse betweenThetford, Brandon and Weeting and in fragments elsewhere.Peats have also formed locally in meres (Corbett 1973) – fluctuating ground-water fed water bodieson the plateaus, all restricted to the Norfolk Breckland. These unusual hydro-geological features arefed by base-rich groundwater with no in-flow or out-flow streams and exhibit concentric zones ofdifferent vegetation due to fluctuation in the water table. Importantly, they are thought to benaturally self sustaining, not silting up or filling in, as vegetation is killed off by drying and reflooding(Rothera 1989). There are five principal meres which are recognised as true fluctuatingground-water fed meres, these are: Langmere, and Ringmere (both at East Wretham Heath),Fowlmere, Home Mere (in STANTA at Thorpe Great Heath) and the Devil’s Punchbowl. There are 3other meres within STANTA which demonstrate some characteristics of fluctuating meres -Smoker's Hole, West Mere and West Tofts Mere. Of these, Smoker's Hole is the most like theprincipal five, the other two are less typical, West Mere may have with underlying impermeablestrata, whilst West Tofts is spring-fed), but which nevertheless exhibit a response to high watertables in the surrounding chalk/sands. The identification of remaining meres is less certain butessentially comprises a series of hollows around the East Wretham/Roudham area, which clearlyhave the same form as the principal meres but that hold water only occasionally when the watertable is particularly high. There are at least seven of these on East Wretham Heath and a further 8through the Roudham Forest block to the east of East Wretham Heath (B. Nichols pers. comm.).Some water bodies near Larling have also been suggested to exhibit fluctuating mere characteristics(Watson, 1974). A number of other waterbodies exist that are rain-fed and lack the characteristicspecies of fluctuating meres.Pingo systems, created by ice lenses during tundra conditions c20, 000 years ago, comprisecomplexes of pools. Within one system, different pools may vary in the extent to which they areground water fed, their pH, whether water levels fluctuate and in their vegetation. This providescomplex range of ecological conditions. Surviving systems occur at Thompson Common, FouldenCommon, East Harling Common, Great Hockham (Hills and Holes), Breckles Heath and FrostsCommon and within STANTA (Rothera 1989; Walmsley 2008).The floristic diversity and interest of the pingo systems arises from variations in substrate,hydrology, water pH and the resulting habitat mosaic (Walmsley 2008). Where water levels withinthe hollows fluctuate, vegetation may be unable to establish for long periods and bare mud on thedraw-down zones can provide opportunities for species that need low levels of competition. High30
quality calcareous fen communities may develop in peat-filled basins fed by calcareous springs, orponds which drain down to damp mud during the summer months (Walmsley 2008).The exceptional invertebrate fauna, which includes numerous RDB species as well as Brecklandspecialities, is attributed to the stability of these habitats over very long periods, as well as the largediversity in habitats (Foster 1993; Lambley, 2005). Foster (1993) observed that: ‘the remnants ofearly postglacial biota’ probably persist because they are often still fed by the same groundwatersource that created them. Snail-killing flies are an outstanding feature at many pingo sites,particularly Thompson Common, which supports a large proportion of the national fauna (Walmsley2008).31
Page 1 and 2: Securing Biodiversityin BrecklandGu
Page 3 and 4: Commissioning GroupNeil Featherston
Page 5 and 6: Wind-blown sand guild .............
Page 7 and 8: milder winters and increased winter
Page 9 and 10: Creating broad ruderal and disturbe
Page 11 and 12: Introduction“Few of the lowland d
Page 13 and 14: Inland DunesThe 1km wide dune and b
Page 15 and 16: Following the Black Death of the mi
Page 17 and 18: The area of grass-heath declined by
Page 19 and 20: PingosPingos are ground water fed p
Page 21 and 22: Breckland Conservation and the Need
Page 23 and 24: SSSI. The Breckland Forest SSSI cit
Page 25 and 26: The Breckland Biodiversity Audit ha
Page 27 and 28: The Breckland bio-geographic region
Page 29: polygons of alternating calcareous
Page 33 and 34: Figure 2. The extent of Breckland,
Page 35 and 36: Table 3. Grass-heath vegetation in
Page 37 and 38: The Conservation Resource: Designat
Page 39 and 40: All other SSSIs are less than 600 h
Page 41 and 42: GrasslandHeathWoodlandWetlandFlowin
Page 43 and 44: Calcicolous grasslandsShingle, stra
Page 45 and 46: Figure 4. Location of designated si
Page 47 and 48: Figure 6. Location of Plantlife’s
Page 49 and 50: Figure 7. Locations of stations in
Page 51 and 52: Scheme for Stilt & Stalk Flies, Dra
Page 53 and 54: Table 6. Rare vascular plant specie
Page 55 and 56: Recommendation BTO be commissioned
Page 57 and 58: Table 7. Species for which records
Page 59 and 60: Table 8. Descriptions of Red Data B
Page 61 and 62: If the sub-species was designated b
Page 63 and 64: Collating and Synthesising Species
Page 65 and 66: Table 11. Published, documentary an
Page 67 and 68: Baron de Worms, C.G.M. (1953) Colle
Page 69 and 70: Guild AnalysisA number of habitat a
Page 71 and 72: The specific questions for the work
Page 73 and 74: Findings of the Breckland Biodivers
Page 75 and 76: Recording Effort and CoverageThere
Page 77 and 78: Butterfly Conservation (Suffolk) 17
Page 79 and 80: Norfolk Biodiversity InformationSer
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Figure 11. Number of taxonomic grou
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difference is partly attributable t
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There were Breckland specialist spe
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Figure 13. Proportion of Breckland
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Distribution of Breckland Conservat
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Figure 15. Number of Breckland cons
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Evidence of Climatic Change: Long-T
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Figure 17. Total seasonal precipita
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Biodiversity Implications of the Ch
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Ariel depositions to agricultural s
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the status of Deschampsia flexuosa.
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The relative effects of ploughing,
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Trends in Species Status: Extinctio
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HymenopteraHymenopteraHymenopteraCo
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In addition to the loss of rare lic
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edstraw Galium parisiense (Tansley
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The relative extent of lichen rich
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The Feasibility and Usefulness of t
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Across patch arrangementLandscape c
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Across patcharrangementJuxtapositio
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Delivery of Multiple Species by Int
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Mechanical disturbance to create br
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estricted to road verges, with the
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Records of species from this guild
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© Jeremy Earlywww.natureconservati
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Open with sward mosaics guildChryso
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Grazing without physical disturbanc
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Deadwood in an open-woodland ecoton
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Specific Requirement in a Variety o
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Management to Sustain Dry Terrestri
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Heather should rather be considered
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GrazingrequirementsLightly sheep-gr
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a mosaic of overlapping ploughed, a
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Wind-blown sandThere is great uncer
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IntensityProcess Technique Immediat
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Complex Sward MosaicsComplex sward
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Management for Assemblages of Light
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Management for Species of Physicall
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Key Recommendations for Cultivated
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Shallow cultivation is preferable t
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Maidscross Hill is largely overgrow
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Ecological Requirements of Wetland
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numbers of conservation priority sp
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Recommendation Requirements of wetl
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Restored pingo complexAt Great Hock
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the difficulties of achieving this
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Strategic Challenges to Biodiversit
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Table 22. Problems arising from poo
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Recommendation: Natural England and
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It is therefore vital to carefully
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Creating networks for resilienceTo
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More ambitious possibilities that c
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Figure 34. Example of a potential c
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Connectivity networks© Neal Armour
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and consider whether these repeated
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Ensure that scrub removal, ploughin
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ReferencesADAS. (1997) Biological M
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Haes, E. C. M. & Harding, P. T. (19
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Sastre, B.(2003). Ground spider com
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Securing Biodiversity in Breckland - European Commission

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