
Important Arable Plant Areas Outstanding Assemblages (Criterion B) Criterion B for outstanding assemblages utilises the same methodology for identifying sites of County, National and European Importance. This is a scoring system that tallies the weighted individual score for each of the species present according to their rarity and decline across Britain. The basic listing of arable species has been drawn from PLANTATT: Attributes of British and Irish Plants (Hill et al. 2004), which provides the most comprehensive listing of species characteristic of arable land currently available. This has been supplemented with a selection of additional species considered to occur occasionally as characteristic members of the arable flora, although some are often equally typical of non-arable habitats. For example, groundpine Ajuga chamaepitys has been recorded growing in short turf and arable fields, and red hemp- nettle Galeopsis angustifolia is found growing in cultivated fields, shingle beaches and on screes. Individual species scores range between 1 (least concern) to 9 (rarest and most threatened) and have been assigned to arable plants based on: i. their current occurrence within 10-km squares, and/or ii. their recent decline (based on the information contained in The New Atlas of the British Flora (Preston et al. 2002), and/or iii. their current species threat status (based on information contained in Cheffings & Farrell 2005, supplemented by that in Wiggington (1999) and Perring & Farrell (1983) (table 1). The most recent update to this list was in 2015 with the addition of two species - greater venus’- looking-glass Legousia speculum-veneris and hairy-fruited cornsalad Valerianella eriocarpa, and the adjustment of scores for neophyte species (species introduced to the UK after 1500) to a maximum of 6 as they do not qualify as threatened (Vulnerable, Endangered or Critically Endangered) under the IUCN guidelines at the UK level (see appendix for a species list). Table 1: Scoring categories for arable plant species Score Status 9 Threatened – Critically Endangered (CR) 8 Threatened – Endangered (EN / E) 7 Threatened – Vulnerable (VU / V) 6 Near threatened (NT) 5 Additionally Nationally Scarce: 16 to 50 10-km squares or 51 to 100 10-km squares and a change index less than -1.0 4 Additionally Nationally Scarce: 51 to 100 10-km squares and a change index greater than -1.0 3 Species of local concern: 101 to 500 10-km squares 2 Species of local concern: 501 – 1000 10-km squares 1 Species of local concern: 1001 to 1500 10-km squares and change index less than 0.0 (i.e. negative) The outstanding assemblage assessment methodology presented here is based on the cumulative total of the weighted scores of species present at each site, allowing the comparison of the relative nature conservation value of different sites. Threshold scores have been proposed for holdings (sites), monads (1x1 km square) and tetrads (2x2 km square) of County, National and European Importance (table 2). Threshold scores have also been established for fields of County, National and European Importance to focus conservation measures (table 3). The scoring system recognises that arable communities on a particular geological substrate may consistently score either more or less than equally valued communities on a different substrate. The thresholds are varied for three broad geological categories: sandy loams, shale and other free-draining soils; slowly permeable clay and silt based soils; and dry calcareous soils on chalk and limestone. Table 2: Threshold scores for assessing the conservation importance of arable plants at the holding (site), monad and tetrad level. Chalky and limestone Clay and slowly Sandy loams, shale derived free-draining impermeable soils and free-draining calcareous soils (inc. calcareous soils clays) European importance 90+ 70+ 70+ National importance 45-89 30-69 35-69 County importance 30-44 20-29 20-34 Table 3: Threshold scores for assessing the conservation importance of arable plants at the field level. Chalky and limestone Clay and slowly Sandy loams, shale derived free-draining impermeable soils and free-draining calcareous soils (inc. calcareous soils clays) European importance 45+ 40+ 45+ National importance 25-44 25-39 30-44 County importance 15-24 15-24 15-29 Further reading Cheffings, C.M. and Farrell, L. (2005) Species Status Report No. 7: The vascular plant red data list for Great Britain. Joint Nature Conservation Committee, Peterborough. Hill, M.O., Preston, C.D. and Roy, D.B. (2004) PLANTATT: Attributes of British and Irish Plants. NERC Centre of Ecology and Hydrology, Monks Wood. Perring, F.H. and Farrell, L. (1983) British Red Data Book I: Vascular plants (2nd edition). Royal Society for Nature Conservation, Lincoln. Preston, C.D., Pearman, D.A. and Dines, T.D. (2001) New Atlas of the British and Irish Flora. Oxford University Press. Wiggington, M.J. (1999) British Red Data Books I: Vascular plants. Joint Nature Conservation Committee, Peterborough. Appendix: Important Arable Plant Area species list and scores at the UK level Plant Species UK UK Status Score Pheasant’s-eye Adonis annua 8 Endangered (RDB status) (234 hectads, change index of -2.19) Corncockle Agrostemma githago 9 Critically Endangered (RDB status) (815 hectads, change index of -0.75) Ground Pine Ajuga chamaepitys 8 Endangered (RDB status) (43 hectads, change index of -0.62) Hairy Mallow or Althaea hirsuta 6 Near Threatened Rough Marsh-mallow (88 hectads, change index of 0.11) Small Alison Alyssum alyssoides 6 Nationally Scarce (0 hectads, change index of -1.24) Blue Pimpernel Anagallis arvensis ssp. 5 Nationally Scarce foemina (no distribution data available) Small Bugloss Anchusa arvensis 1 Least Concern (RDB status) (1514 hectads, change index of -0.7) Corn Chamomile Anthemis arvensis 8 Endangered (RBD status) Stinking Chamomile Anthemis cotula 7 Vulnerable (RBB status) Annual Vernal-grass Anthoxanthum 6 Near Threatened aristatum (93 hectads, change index of -2.65) Bur Chervil Anthriscus caucalis 3 Least Concern (RDB status) (659 hectads, change index of -0.16) Dense Silky-bent Apera interrupta 4 Nationally Scarce (104 hectads, change index of 0.8) Loose Silky-bent Apera spica-venti 6 Near Threatened (RDB status) (326 hectads, change index of -0.21) Slender Parsley-piert Aphanes australis 1 Least Concern (RDB status) (1549 hectads, no change index) Lamb’s-succory Arnoseris minima 9 Extinct (RDB status) (83 hectads, change index of -3.72) Bristle Oat Avena strigosa 5 Nationally Scarce (No RBD status) (270 hectads, change index of -3.01) Black Mustard Brassica nigra 2 Least Concern (RDB status) (1080 hectads, change index of -0.02) Lesser Quaking-grass Briza minor 5 Nationally Scarce (RDB status) (92 hectads, change index of 0.28) Field Brome Bromus arvensis 6 Near Threatened (no distribution, change index of -3.15) Interrupted Brome Bromus interruptus 6 Nationally Scarce (no distribution, change index of -1.73) Rye Brome Bromus secalinus 7 Vulnerable (RDB status) (403 hectads, change index of -1.15) Greater Pignut Bunium bulbocastanum 6 Near Threatened (13 hectads, change index of 0.14) Thorow-wax Bupleurum 9 Critically endangered (RDB status) rotundifolium (287 hectads, change index of -4.58) False Flax Camelina sativa 5 Nationally Scarce (RDB Status) (248 hectads, no change index) Small Bur-parsley Caucalis platycarpos 9 Extinct (RDB status) (no distribution information) Plant Species UK UK Status Score Cornflower Centaurea cyanus 8 Endangered (884 hectads, change index of -0.39) Small Toadflax Chaenorhinum minus 1 Least Concern (RBD status) (1468 hectads, change index of -0.63) Fig-leaved Goosefoot Chenopodium 2 Least Concern (RDB status) ficifolium (745 hectads, 1.9) Maple-leaved Goosefoot Chenopodium 3 Least Concern (RDB status) hybridum (285 hectads, -0.32) Nettle-leaved Goosefoot Chenopodium murale 7 Vulnerable (RDB status) (412 hectads, -1.63) Many-seeded Goosefoot Chenopodium 2 Least Concern (RDB status) polyspermum (998 hectads, 0.62) Upright Goosefoot Chenopodium urbicum 9 Critically Endangered (RDB status) (239 hectads, -4.57) Tansy Mustard or Flixweed Descurainia sophia 3 Least Concern (RDB status) (636 hectads, -0.29) Purple Bugloss Echium plantagineum 6 Near Threatened (79 hectads, 0.36) Common Stork's-bill Erodium cicutarium 1 Least Concern (RDB status) (no distribution, -0.11) Musk Stork’s-bill Erodium moschatum 3 Least Concern (RDB status) (338 hectads, 0.47) Treacle Mustard Erysimum 2 Least Concern (RDB status) cheiranthoides (929 hectads, -0.65) Dwarf Spurge Euphorbia exigua 6 Near Threatened (RDB status) (1039 hectads, -1.18) Broad-leaved Spurge Euphorbia platyphyllos 3 Least Concern (RDB status) (248 hectads, -0.24) Narrow-leaved Cudweed Filago gallica 9 Extinct (RDB status) (21 hectads, 0.01) Red-tipped Cudweed Filago lutescens 8 Endangered (RDB status) (85 hectads, -0.34) Broad-leaved Cudweed Filago pyramidata 8 Endangered (RDB status) (132 hectads, -1.14) Common Cudweed Filago vulgaris 6 Near Threatened (RDB status) (980 hectads, -1.2) Tall Ramping-fumitory Fumaria bastardii 2 Least Concern (RDB status) (423 hectads, 0.39) White Ramping-fumitory Fumaria capreolata 3 Least Concern (RDB status) (482 hectads, 0.31) Dense-flowered Fumitory Fumaria densiflora 3 Least Concern (RDB status) (307 hectads, -0.37) Common Ramping- Fumaria muralis ssp. 7 Vulnerable (RDB status) fumitory neglecta (no distribution data) Western Fumitory Fumaria occidentalis 5 Nationally Scarce (31 hectads, 0.04) Fine-leaved Fumitory Fumaria parviflora 7 Vulnerable
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