4f4c4942-4343-5764-6473-313138383938 English NRW_DS23774 Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2024-05-31T09:41:17.886Z NRW 1.0 wel British National Grid (EPSG::27700) A Survey for Desmoulin’s Whorl Snail Vertigo moulinsiana on Cors Geirch National Nature Reserve / Site of Special Scientific Interest and the Afon Penrhos Floodplain (2016) A Survey for Desmoulin’s Whorl Snail Vertigo moulinsiana on Cors Geirch National Nature Reserve / Site of Special Scientific Interest and the Afon Penrhos Floodplain (2016) Arolwg Falwen Droellog Desmoulin Vertigo moulinsiana ar Warchodfa Natur Genedlaethol/Safle o Ddiddordeb Gwyddonol Arbennig Cors Geirch a Gorlifdir Afon Penrhos (2016) 2017-03-31 NRW_DS118898 A survey for Desmoulin's Whorl Snail Vertigo moulinsiana on Cors Geirch National Nature Reserve (NNR)/ Site of Special Scientific Interest (SSSI) and the Afon Penrhos floodplain was undertaken in October 2016 to determine its current status and distribution. Sampled locations were based upon the results of previous surveys at Cors Geirch (1999-2008) and Afon Penrhos (2002-2008). The population at Cors Geirch was found to have declined considerably, with a complete loss of the snail from former stronghold areas and just 17 shells recorded from two small areas at the southern end of the site. Assessments in 2003 and 2008 had considered the population to be in favourable condition. With an eight-year monitoring hiatus, the causes of the sharp decline are unclear but are likely to include the spread of uncut and un-grazed rank, fen vegetation combined with encroaching birch and sallow. Dense vegetation growth at the site was such that the former ditch-lines, used as features for site monitoring, were almost completely obscured and difficult to reach. At Afon Penrhos, the snail was found in large numbers in short, mechanically-cut and lightly horse-grazed 'fen-meadow'; tall uncut fen supported significantly lower numbers. Elsewhere in the UK, the snail is typically associated with tall fen. Vertigo moulinsiana was recorded on about 19 acres (8 hectares) of the site, but population boundaries were not established on the eastern and south-east borders of the surveyed area. It is estimated that a further 75 acres (30 hectares) of potentially-suitable habitat exists which should be surveyed to determine if it supports the snail. The Afon Penrhos population is not only the largest in Wales, but also probably one of the largest in mainland Britain. The significance of the population here is further enhanced by recent considerable population losses at several Special Areas of Conservation(SAC) in southern England. Once the full extent of the population on Afon Penrhos is determined, it is recommended that the site should be notified as a SSSI to reduce any risk of loss or damage due to changes in site management. In light of the snail's association with short 'fen-meadow' at Afon Penrhos, it is recommended that rank areas which previously supported Vertigo moulinsiana on Cors Geirch are opened up to provide short fen habitat to assist the recovery of the remnant population. A survey for Desmoulin's Whorl Snail Vertigo moulinsiana on Cors Geirch National Nature Reserve (NNR)/ Site of Special Scientific Interest (SSSI) and the Afon Penrhos floodplain was undertaken in October 2016 to determine its current status and distribution. Sampled locations were based upon the results of previous surveys at Cors Geirch (1999-2008) and Afon Penrhos (2002-2008). The population at Cors Geirch was found to have declined considerably, with a complete loss of the snail from former stronghold areas and just 17 shells recorded from two small areas at the southern end of the site. Assessments in 2003 and 2008 had considered the population to be in favourable condition. With an eight-year monitoring hiatus, the causes of the sharp decline are unclear but are likely to include the spread of uncut and un-grazed rank, fen vegetation combined with encroaching birch and sallow. Dense vegetation growth at the site was such that the former ditch-lines, used as features for site monitoring, were almost completely obscured and difficult to reach. At Afon Penrhos, the snail was found in large numbers in short, mechanically-cut and lightly horse-grazed 'fen-meadow'; tall uncut fen supported significantly lower numbers. Elsewhere in the UK, the snail is typically associated with tall fen. Vertigo moulinsiana was recorded on about 19 acres (8 hectares) of the site, but population boundaries were not established on the eastern and south-east borders of the surveyed area. It is estimated that a further 75 acres (30 hectares) of potentially-suitable habitat exists which should be surveyed to determine if it supports the snail. The Afon Penrhos population is not only the largest in Wales, but also probably one of the largest in mainland Britain. The significance of the population here is further enhanced by recent considerable population losses at several Special Areas of Conservation(SAC) in southern England. Once the full extent of the population on Afon Penrhos is determined, it is recommended that the site should be notified as a SSSI to reduce any risk of loss or damage due to changes in site management. In light of the snail's association with short 'fen-meadow' at Afon Penrhos, it is recommended that rank areas which previously supported Vertigo moulinsiana on Cors Geirch are opened up to provide short fen habitat to assist the recovery of the remnant population. Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Willing c/o Natural Resources Wales, Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW enquiries@naturalresourceswales.gov.uk http://naturalresourceswales.gov.uk Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en sd">Species distribution Protected sites Habitats and biotopes Species distribution GEMET - INSPIRE themes, version 1.0 GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme vertigo moulinsiana whorl snails Desmoulin's whorl snail species conservation (species protection) NRW Thesaurus NRW Thesaurus 2023-12-31 geonetwork.thesaurus.local.theme.converted_nrw-keywords There are no access restrictions to this data. NRW may release, publish or disseminate it freely. no limitations © CNC/NRW Data may be re-used under the terms of the Open Government Licence providing it is done so, acknowledging both the source and NRW's copyright. It is the recipient's responsibility to ensure the data is fit for the intended purpose. English biota SeaVoX Vertical Co-ordinate Coverages SeaVoX Vertical Co-ordinate Coverages 2021-01-06 GWYNEDD - GWYNEDD -4.6818 -4.2872 52.8182 53.0606 2016-10-03 2016-10-05 Willing, MJ., (2017), A survey for Desmoulin’s Whorl Snail Vertigo moulinsiana on Cors Geirch NNR/SSSI and the Afon Penrhos floodplain in 2016, NRW Evidence Report No: 210, 36pp., Natural Resources Wales, Bangor. A survey of Desmoulin's Whorl Snail Vertigo moulinsiana on Cors Geirch NNR/SSSI and the Afon Penrhos flood in 2016 Database [A] The final report in Microsoft Word and Adobe PDF formats. [B] Species records, which are held on the NRW Recorder 6 database. https://registry.nbnatlas.org/public/show/dr1212 Data Download World Wide Web page Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services 2010-12-08 false Surveys were by visual searches and the collection of samples of suitable vegetation for drying and sieving. Surveys were by visual searches and the collection of samples of suitable vegetation for drying and sieving.