4f4c4942-4343-5764-6473-313032303131 English NRW_DS109834 Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2026-10-19T14:36:55.965Z NRW 1.0 wel utf8 British National Grid (EPSG::27700) Intertidal Monitoring of Muddy Gravel Community (IMX.VsenMtru) in the Pen Llyn a'r Sarnau Special Area of Conservation (SAC) 2004 Intertidal Monitoring of Muddy Gravel Community (IMX.VsenMtru) in the Pen Llyn a'r Sarnau Special Area of Conservation (SAC) 2004 Monitro Cymuned Graean Lleidiog (IMX.VsenMtru) rhynglanwol yn ACA Pen Llyn a'r Sarnau yn 2004 2004 CCW / IECS Pen Llyn a'r Sarnau SAC muddy gravel community (IMX.VsenMtru) monitoring (MRCCW3030000000B) 2008-12-31 NRW_DS102011 http://naturalresources.wales/ The results of monitoring the extent and species richness of a distinct area of mixed sediment that lies east of Llanbedrog beach. The muddy gravel community is - IMX.VsenMtru (Venerupis senegalensis and Mya truncata in lower shore or infralittoral muddy gravel), and has a high biodiversity of epifauna, flora and infauna, due to the admixture of cobbles, pebbles, gravel, sand and mud. This provides many different habitat niches. The habitat is located within the Pen Llyn a'r Sarnau Special Area of Conservation (SAC) on the lower shore at Llanbedrog. In fully marine conditions on the lower shore, this habitat can be particularly species rich due to the complex nature of the substratum supporting a high diversity of infauna and epifauna, however many factors affect the habitat, physical disturbance, bait digging, organic enrichment, introduction of non-native species etc. The purpose of this data capture was to map the current extent of muddy gravel, define the character of the muddy gravel for in situ recognition, identify current known species composition and identify location for representative core sampling and Particle Size Analysis. The results of monitoring the extent and species richness of a distinct area of mixed sediment that lies east of Llanbedrog beach. The muddy gravel community is - IMX.VsenMtru (Venerupis senegalensis and Mya truncata in lower shore or infralittoral muddy gravel), and has a high biodiversity of epifauna, flora and infauna, due to the admixture of cobbles, pebbles, gravel, sand and mud. This provides many different habitat niches. The habitat is located within the Pen Llyn a'r Sarnau Special Area of Conservation (SAC) on the lower shore at Llanbedrog. In fully marine conditions on the lower shore, this habitat can be particularly species rich due to the complex nature of the substratum supporting a high diversity of infauna and epifauna, however many factors affect the habitat, physical disturbance, bait digging, organic enrichment, introduction of non-native species etc. The purpose of this data capture was to map the current extent of muddy gravel, define the character of the muddy gravel for in situ recognition, identify current known species composition and identify location for representative core sampling and Particle Size Analysis. 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 Countryside Council for Wales (CCW) Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW enquiries@naturalresourceswales.gov.uk http://naturalresourceswales.gov.uk/splash?orig=/ Hull University. Institute Of Estuarine And Coastal Studies The University of Hull, Cottingham Road, Hull, HU6 7RX iecs@hull.ac.uk http://www.hull.ac.uk/iecs/ Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en Habitats and biotopes GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme Pen Llyn a'r Sarnau SAC Marine Recorder NI biotope Muddy gravel NRW Thesaurus 2026-08-27 geonetwork.thesaurus.local.theme.converted_nrw-keywords Habitat characterisation SeaDataNet Parameter Discovery Vocabulary 2024-06-19 geonetwork.thesaurus.external.theme.rdf+xml 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. 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 benthic boundary layer Wales (WLS) -4.476854926 -4.465002212 52.85471557 52.8631457 2004-07-07 2005-01-31 Intertidal monitoring of a muddy gravel community (VsenMtru) in Pen Llyn a'r Sarnau in 2004 Database Marine Recorder Online - Version 2.09.02 Marine Recorder 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 Survey conducted on foot, working 2 hours either side of low water. The survey team identified and recorded species in situ where possible, samples were taken of any species that could not be immediately identified in the field for further analysis by experienced IECS benthic staff. Representative photos of the habitat were taken throughout the survey. A suitable location (representative of the overall nature of the biotope) was identified, and the position recorded for comparability of future surveys. At this five replicate core samples, each 10 cm diameter (0.0078 m2), and one sample for PSA were taken to establish infaunal biomass and sediment characteristics (January 2005). Distribution of IMX.VsenMtru previously mapped in the area during Phase 1 survey carried out by CCW in 1996.The extent of muddy gravel was mapped by walking around the biotope perimeter recording the boundary position with a portable dGPS. Notes were recorded in situ with respect to sediment characteristics and features of the biotope. Infaunal sample does not coincide with epibiota records. Epibiota recording of moderate confidence. Positional accuaracy of 1-5 m. Survey conducted on foot, working 2 hours either side of low water. The survey team identified and recorded species in situ where possible, samples were taken of any species that could not be immediately identified in the field for further analysis by experienced IECS benthic staff. Representative photos of the habitat were taken throughout the survey. A suitable location (representative of the overall nature of the biotope) was identified, and the position recorded for comparability of future surveys. At this five replicate core samples, each 10 cm diameter (0.0078 m2), and one sample for PSA were taken to establish infaunal biomass and sediment characteristics (January 2005). Distribution of IMX.VsenMtru previously mapped in the area during Phase 1 survey carried out by CCW in 1996.The extent of muddy gravel was mapped by walking around the biotope perimeter recording the boundary position with a portable dGPS. Notes were recorded in situ with respect to sediment characteristics and features of the biotope. Infaunal sample does not coincide with epibiota records. Epibiota recording of moderate confidence. Positional accuaracy of 1-5 m.