4f4c4942-4343-5764-6473-313231313230 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 2025-12-24T09:32:36.661Z NRW 1.0 wel British National Grid (EPSG::27700) Monitoring Invertebrate features on Sites of Special Scientific Interest (SSSIs): assessing and reviewing the status of the troglobitic spider Porrhomma rosenhaueri in Ogof y Ci and Lesser Garth Cave, South Wales in 2017 Monitoring Invertebrate features on Sites of Special Scientific Interest (SSSIs): assessing and reviewing the status of the troglobitic spider Porrhomma rosenhaueri in Ogof y Ci and Lesser Garth Cave, South Wales in 2017 Monitro nodweddion Infertebratau o Safleoedd o Ddiddordeb Gwyddonol Arbennig (SoDdGA): asesu ac adolygu statws y corynod Porrhomma rosenhaueri yn Ogof y Ci ac Ogof Ffynnon Taf De Cymru yn 2017 2018-01-01 NRW_DS121120 This dataset was collected to assess whether Porrhomma rosenhaueri was still present in the Ogof y Ci cave system and if so, to consider the viability of establishing a Common Standards Monitoring (CSM) protocol for monitoring the population within the cave; and to revisit the CSM established for the Lesser Garth Cave to collate further data on the condition of both the Porrhomma rosenhaueri population and the ecological condition of the cave. The cave-dwelling spider Porrhomma rosenhaueri (L. Koch) is unique to the British fauna as it is considered to be the only species of paleotroglobitic spider present, and whilst the cavernicolous fauna of the UK has undoubtedly been under-recorded, sufficient work has occurred to suggest that Porrhomma rosenhaueri is genuinely rare.The spider has a very limited distribution in the UK and is only known from two sites in South Wales, Ogof y Ci near Merthyr Tydfil and Lesser Garth Cave near Cardiff. The Ogof y Ci population was first discovered in 1971 but since this period no recorded survey work on the spider has taken place and the status of the spider within the cave was unknown. The Lesser Garth Cave population was discovered in 1979 during an investigation of the cave for the cave dwelling isopod Proasellus cavaticus. The cave has since been surveyed for the spider on a number of occasions, initially in 1997 as part of an environmental impact assessment, and more recently in 2009 in order to establish a Common Standards Monitoring (CSM) protocol for the longer-term monitoring of the spider population in the cave. This dataset was collected to assess whether Porrhomma rosenhaueri was still present in the Ogof y Ci cave system and if so, to consider the viability of establishing a Common Standards Monitoring (CSM) protocol for monitoring the population within the cave; and to revisit the CSM established for the Lesser Garth Cave to collate further data on the condition of both the Porrhomma rosenhaueri population and the ecological condition of the cave. The cave-dwelling spider Porrhomma rosenhaueri (L. Koch) is unique to the British fauna as it is considered to be the only species of paleotroglobitic spider present, and whilst the cavernicolous fauna of the UK has undoubtedly been under-recorded, sufficient work has occurred to suggest that Porrhomma rosenhaueri is genuinely rare.The spider has a very limited distribution in the UK and is only known from two sites in South Wales, Ogof y Ci near Merthyr Tydfil and Lesser Garth Cave near Cardiff. The Ogof y Ci population was first discovered in 1971 but since this period no recorded survey work on the spider has taken place and the status of the spider within the cave was unknown. The Lesser Garth Cave population was discovered in 1979 during an investigation of the cave for the cave dwelling isopod Proasellus cavaticus. The cave has since been surveyed for the spider on a number of occasions, initially in 1997 as part of an environmental impact assessment, and more recently in 2009 in order to establish a Common Standards Monitoring (CSM) protocol for the longer-term monitoring of the spider population in the cave. 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 National Museums and Galleries of Wales Education Department, Cathays Park, Cardiff, Vale of Glamorgan, CF1 3NP post@nmgw.ac.uk http://www.museumwales.ac.uk/ Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Protected sites Habitats and biotopes Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme caves cave spider porrhomma rosenhaueri invertebrate surveys biological monitoring ecological surveys biological surveys NRW Thesaurus 2025-01-08 geonetwork.thesaurus.local.theme.converted_nrw-keywords There are no access restrictions on 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. Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Open Government Licence English biota SeaVoX Vertical Co-ordinate Coverages 2021-01-06 Wales (WLS) -3.70477214 -3.10727323 51.69710711 52.07877084 2017-09-09 2017-10-31 Monitoring Invertebrate features on SSSIs: assessing and reviewing the status of the troglobitic spider Porrhomma rosenhaueri in Ogof y Ci and Lesser Garth Cave, South Wales in 2017 Database [A] Database - records held in WID -Recorder 6. [B] Documents: pdf of the report in the DMS report archive. 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 This dataset has not been assessed for conformance to the referenced INSPIRE regulation. false Surveys were by visual searches. The survey of Ogof y Ci, along with other accessible sites within the Nant Glais Caves SSSI, was the primary objective of the survey work. Two site visits were carried out in September and October 2017 to assess biospeleology of the Nant Glais SSSI and to survey Ogof y Ci for Porrhomma rosenhaueri. The spider was found to be still present within the Ogof y Ci cave complex, the first record since 1971, with a total of seven live spiders found during the site survey providing sufficient information to suggest a future monitoring protocol for the cave. The repeat of the CSM protocol for the Lesser Garth Cave occurred during October 2017 and gave comparable numbers of spiders (15 adults and subadults, and up to 47 webs) and their distribution within the cave to the 2009 survey work suggesting a stable population within the cave. Overall, this survey work demonstrates that Porrhomma rosenhaueri is still present at both of its known locations, and that both cave sites support important cave invertebrate habitats within the UK. Surveys were by visual searches. The survey of Ogof y Ci, along with other accessible sites within the Nant Glais Caves SSSI, was the primary objective of the survey work. Two site visits were carried out in September and October 2017 to assess biospeleology of the Nant Glais SSSI and to survey Ogof y Ci for Porrhomma rosenhaueri. The spider was found to be still present within the Ogof y Ci cave complex, the first record since 1971, with a total of seven live spiders found during the site survey providing sufficient information to suggest a future monitoring protocol for the cave. The repeat of the CSM protocol for the Lesser Garth Cave occurred during October 2017 and gave comparable numbers of spiders (15 adults and subadults, and up to 47 webs) and their distribution within the cave to the 2009 survey work suggesting a stable population within the cave. Overall, this survey work demonstrates that Porrhomma rosenhaueri is still present at both of its known locations, and that both cave sites support important cave invertebrate habitats within the UK.