Jncc coastal Directories Project Region 11 The Western Approaches
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- Bu səhifədəki naviqasiya:
- Region 11 Chapter 5 Important species 94 Table 5.3.3 Sites important for invertebrate conservation Site Grid ref.
- Isles of Scilly SV80-SV81 SV90-SV91 Many ISR sites covering the main islands, some of them SSSI Devon
- 5.3.3 Human activities
- 5.3.4 Information sources used
- 5.3.5 Acknowledgements
Region 11 Chapter 5 Important species 94 Table 5.3.3 Sites important for invertebrate conservation Site Grid ref. Status Cornwall Swanpool SW8031 Mawnan Glebe SW7826 NT Merthen Wood SW7326 SSSI Gweek Wood SW7026 Coverack Cliffs SW7818 SSSI Kennack Cove to Blackhead Cliffs (including Beagles Point) SW7616 SSSI/NT (in part) South & east Lizard SW6911 SSSI/NT Kynance Cove SW6813 SSSI/NT (in part)/Wildlife Trust reserve West Lizard SW6616 NNR/SSSI/NT (in part) Mullion Cliffs to Predannack Head SW6617 SSSI/NT/Wildlife Trust reserve Gunwalloe Church Cove and Marsh SW6620 NT Loe Pool SW6424 SSSI/NT Porthleven Cliffs SW6324 SSSI/NT Marazion Marsh SW5131 SSSI Treen Cliff SW4022 SSSI/NT Sennen Cove SW3526 Cape Cornwall to Clodgy Point SW3531-SW5041 SSSI/NT (in part) Gwithian to Mexico Towans SW5740 SSSI Godrevy Head to St. Agnes SW5842-SW7151 SSSI/NT (in part) Cligga Head SW7254 SSSI Penhale Dunes SW7757 SSSI/NT (in part) Kelsey Head (including Holywell Bay) SW7660 SSSI/NT (in part) Trevose Head and Constantine Bay SW8575 SSSI Pentire Peninsula SW9280 SSSI/NT Tintagel Cliffs SX0487 SSSI/NT (in part) Boscastle to Widemouth SX0991- SS1901 SSSI/NT(in part) Steeple Point to Marsland Mouth SS2117-SS0211 SSSI/NT (in part)/Wildlife Trust reserve (in part) Isles of Scilly SV80-SV81 & SV90-SV91 Many ISR sites covering the main islands, some of them SSSI Devon Marsland Mouth to Clovelly SS2117-SS3125 SSSI/NT (in part)/Wildlife Trust reserve (in part) Lundy Island SS1346 SSSI/NT/Landmark Trust/Marine Nature Reserve Hobby to Peppercombe SS3224-SS3824 SSSI/NT Babbacombe Mouth SS3924 NT Westward Ho! Cliffs SS4026 SSSI Northam Burrows SS4431 LNR Braunton Burrows SS4635 SSSI/Biosphere Reserve Saunton to Baggy Point SS4438 SSSI/NT Morte Point SS4545 SSSI/NT West Exmoor coast and woods SS6654 SSSI/NT Watersmeet SS7448 SSSI/NT Foreland Point SS7551 NT Somerset Porlock Marsh SS8747 SSSI/NT Berrow Dunes ST2952 SSSI/LNR Brean Down ST2959 SSSI/NT Severn Estuary ST2859-ST1968 SSSI Avon Steep Holm ST2260 SSSI Middle Hope ST3265 SSSI/NT/Wildlife Trust reserve Gwent Gwent Levels (includes Caldicot, Magor & Wentlooge Levels) ST28, ST38 SSSI/Wildlife Trust reserve Mid-Glamorgan Methyr Mawr dunes SS8477 SSSI Kenfig Pool & dunes SS7980 SSSI/NNR Source: JNCC ISR. Key: NNR = National Nature Reserve; SSSI = Site of Special Scientific Interest; NT = National Trust; LNR = Local Nature Reserve. Sand dune systems have many scarce species, including some restricted to south-western coasts, for example the bugs Geotomus punctulatus and Halticus macrocephalus, both of which feed on lady’s bedstraw Galium verum at just a few dunes in Cornwall. The damp dune slacks at Braunton Burrows are one of only two localities in Britain for the sandbowl snail Catinella arenaria. The click beetle Dicronychus equiseti is known only from marram dunes in Devon and south Wales, and the ground beetle Nebria complanata has a similarly restricted distribution, inhabiting strandline habitats along sandy foreshores. Coastal wet grasslands (see section 3.5 ) support a number of scarce and threatened species associated, in one or more stages of their life histories, with the water-filled rhyns (ditches). The best examples of these habitats occur in Somerset and Gwent, where the great silver water beetle Hydrophilus piceus, the diving beetle Hydaticus transversalis and the soldier fly Odontomyia ornata abound. Two species afforded statutory protection ( Table 5.3.1 ) are recorded from water bodies in the region - the medicinal leech Hirudo medicinalis, from a large dune pool, and the fairy shrimp Chirocephalus diaphanus, from temporary pools. A further rarity associated with temporary pools is the mud snail Lymnaea glabra. Wooded ria valleys in Cornwall are home to the threatened weevil Anchonidium unguiculare, which lives in leaf litter. Other scarce species occurring in these woodlands include moths whose larvae feed on epiphytic lichens on trees: the dotted carpet Alcis jubata is one example. Wooded combes in Devon and Somerset linked to sheltered areas of heath or bracken provide habitat for two threatened butterflies: the high brown fritillary Argynnis adippe and the heath fritillary Mellicta athalia. 5.3.3 Human activities As with other nature conservation interests, the main threats to invertebrate communities in the region include inappropriate management of sites and direct habitat loss or degradation, such as by construction of stabilising sea defences or the clearing away of organic strandline debris. Appropriate site management is vital for maintaining invertebrate interest, since invertebrates occur in the full range of coastal habitats and many require particular microhabitats in a suitable condition, often using subtle features of vegetation structure or areas of bare ground. As invertebrates generally have annual life cycles, the habitat features they utilise must be present in the right condition in each and every year. This is compounded by the fact that many scarce species have poor powers of dispersal and are thus unable to colonise suitable habitat from afar. Site management often overlooks many features that are of importance to invertebrates, many species surviving by default. Grazing has the potential to both create and destroy or damage invertebrate habitat. Appropriate levels of grazing maintain the varied ground conditions and heights of sward that favour a variety of invertebrates. However, too heavy grazing reduces the value of, for example, maritime grassland for invertebrates, by increasing nutrient levels in the soil and altering soil structure, thus changing the plant species that occur and restricting the height of the vegetation. Along flushes, where ground water emerges along slopes, heavy poaching can be particularly damaging, as the trampling crushes the soft plants and cuts through the sward, leading to soil erosion and muddying of the water. On some sites insufficient or no grazing allows vegetation to become rank and dense, reducing the range of species that it can support and favouring commoner species. The fundamentals of managing coastal habitats for invertebrates are covered by Kirby (1992). 5.3.4 Information sources used The data used here come from the ISR, a computerised GB- wide database based on literature searches of entomological journals and those of local naturalist societies, collation of data from local biological record centres and the Biological Records Centre, Monks Wood, and consultation with invertebrate specialists and non-governmental organisations. The level of recording around the region varies considerably, although a few areas have been studied in considerable detail. Most of the better known invertebrate groups have been recorded in the region, although some much more so than others. The Hemiptera (true bugs), Lepidoptera (butterflies and moths), Coleoptera (beetles) and Hymenoptera (solitary bees and wasps) are among the best studied groups. Some areas, for example the Lizard peninsula in Cornwall, have been extensively recorded in both historic and modern times. Even so, new discoveries are still made; examples include the discovery of micro- moth species new to science (Heckford & Langmaid 1988) or previously unknown from Great Britain (Heckford 1986) and of a new subspecies, Lupernia nickerlii leechi, of the sandhill rustic moth (Goater 1976). Several modern publications review the occurrence of invertebrates within the region, with Fowles (1994) providing an overview of the most important sites and species in Wales. On a county basis, Duff (1993) covers the beetles of Somerset and Horton (1994) the butterflies and moths of Monmouthshire. In addition, other publications have mapped the distribution of certain groups on a county basis: for example Bristow et al. (1993) deals with the butterflies of Devon and Randolph (1992) the dragonflies in counties around Bristol. Extensive invertebrate surveys have been undertaken, concentrating on particular habitat types: Drake (1986) covers many of the groups occurring in wet grasslands on the Gwent Levels. In addition, there are numerous publications in entomological journals relating to this region: for invertebrates of the Isles of Scilly and Lundy Island, bibliographies for certain groups or areas are provided by Smith & Smith (1983); Chalmers-Hunt (1989) lists publications for Lepidoptera. Colvin & Reavey (1993) provides a more comprehensive list of addresses for societies, individuals and national and local recording schemes. 5.3.5 Acknowledgements Thanks are due to D. Procter and Dr S. Ball (JNCC) for providing raw data from the ISR ( Table 5.3.1 ) and for assistance in producing maps. 5.3 Land and freshwater invertebrates 95 Yüklə 10,91 Mb. Dostları ilə paylaş:
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