4f4c4942-4343-5764-6473-313136373936 English Natural Resources Wales (NRW) Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales enquiries@naturalresourceswales.gov.uk http://naturalresources.wales/?lang=en 2025-12-24T09:27:30.395Z NRW 1.0 wel British National Grid (EPSG::27700) Invertebrates Recorded on Exposed Riverine Sediments at Llanelltyd on the Afon Mawddach in 2016. Invertebrates Recorded on Exposed Riverine Sediments at Llanelltyd on the Afon Mawddach in 2016. Creaduriaid Di-asgwrn-cefn a Gofnodwyd ar Waddodion Afonol Agored yn Llanelltud ar Afon Mawddach yn 2016 The importance of exposed riverine sediments at Llanelltyd on the Afon Mawddach for invertebrates in 2016. 2016-12-31 NRW_DS116796 In order to alleviate flooding problems on the Afon Mawddach at Llanelltyd, Natural Resources Wales is considering the removal of gravel from shingle bars immediately upstream and downstream of the bridge. Data was collected to evaluate the current significance of these bars for Exposed Riverine Sediments invertebrates and to indicate the possible impact of gravel removal on the Exposed Riverine Sediments fauna. This dataset holds specialist invertebrate species of Exposed Riverine Sediments recorded on three dates in July and September 2016. Comparisons are made with a similar survey carried out on the Tan-lan bar in 2003 and Exposed Riverine Sediment Quality Indices are presented. Unseasonal floods during August and September may have limited the range of species, but it would also appear that changes to the topography of the Tan-lan (upstream) sediment bar may also be responsible for limiting the area of habitat. The current survey did not yield sufficient species to allow a reliable index to be calculated but there is no reason to suppose that the Llanelltyd shingle bars are no longer important to the Exposed Riverine Sediments assemblage on the river. In order to alleviate flooding problems on the Afon Mawddach at Llanelltyd, Natural Resources Wales is considering the removal of gravel from shingle bars immediately upstream and downstream of the bridge. Data was collected to evaluate the current significance of these bars for Exposed Riverine Sediments invertebrates and to indicate the possible impact of gravel removal on the Exposed Riverine Sediments fauna. This dataset holds specialist invertebrate species of Exposed Riverine Sediments recorded on three dates in July and September 2016. Comparisons are made with a similar survey carried out on the Tan-lan bar in 2003 and Exposed Riverine Sediment Quality Indices are presented. Unseasonal floods during August and September may have limited the range of species, but it would also appear that changes to the topography of the Tan-lan (upstream) sediment bar may also be responsible for limiting the area of habitat. The current survey did not yield sufficient species to allow a reliable index to be calculated but there is no reason to suppose that the Llanelltyd shingle bars are no longer important to the Exposed Riverine Sediments assemblage on the river. 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 Fowles c/o Natural Resources Wales, 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 Protected sites Habitats and biotopes Species distribution GEMET - INSPIRE themes, version 1.0 2008-06-01 geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme invertebrate surveys staphylinidae rove beetles Exposed Riverine Sediment (ERS) invertebrates (see also specific species) 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 environment SeaVoX Vertical Co-ordinate Coverages 2021-01-06 GWYNEDD - GWYNEDD -3.905861175 -3.895539151 52.7547367 52.75898401 2016-07-29 2016-09-14 Fowles, A.P. (2016), The importance of exposed riverine sediments at Llanelltyd on the Afon Mawddach for invertebrates in 2016, NRW Evidence Report No: 182, 21pp, Natural Resources Wales, Bangor. The importance of exposed riverine sediments at Llanelltyd on the Afon Mawddach for invertebrates in 2016 Database [A] Published report – electronic version (Microsoft Word and Adobe PDF formats) [B] Species records, which are held on the NRW Recorder 6 database (Welsh Invertebrate Database) https://registry.nbnatlas.org/public/show/dp122 WWW:LINK-1.0-http--link Data Download 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 Sampling techniques included visual searches, splash-sampling and excavation sampling. Invertebrate identifications were by a competent taxonomist. Sampling techniques included visual searches, splash-sampling and excavation sampling. Invertebrate identifications were by a competent taxonomist.