Statws y Falwen Droellog Desmoulin (Vertigo moulinsiana) yng Ngwarchodfa Natur Genedlaethol Rhos Goch (GNG) (2015)
This dataset comprises the results of a survey for Desmoulin's Whorl Snail (Vertigo moulinsiana) conducted in 2015. The survey confirmed the species' continued presence at Rhos Goch National Nature Reserve (NNR) following its discovery there in 2007, making it one of only three known sites for the species in Wales.
Despite being a small snail, Vertigo moulinsiana is the largest Vertigo species, with a shell height of up to approximately 2.6 mm. The species is known from only three localities in Wales: Cors Geirch and Afon Penrhos near Pwllheli on the Llŷn Peninsula, and Rhos Goch National Nature Reserve near Hay-on-Wye in Radnorshire. All Welsh V. moulinsiana sites are isolated and differ from the base-rich lake and riverside fens that are typically associated with the species across much of its English range.
The conservation importance of the species has led to its inclusion in various legislative schedules and Red Data Lists. It was categorised as Rare (Category 3) in the UK Red Data Books and has more recently been classified as Vulnerable in the IUCN-based UK Red List status review. The species is listed on Annex IIa of the European Community Habitats and Species Directive (92/43/EEC) and is also a Welsh Section 42 Species of Principal Importance (which replaced the UK Biodiversity Action Plan priority species list in 2006).
The purpose of this survey was to assess the presence and distribution of V. moulinsiana, focusing initially on areas where the species was recorded in 2007 and subsequently undertaking a wider search of potentially suitable habitat within the NNR and the adjoining Site of Special Scientific Interest (SSSI).
- Dull adnabod
- Rhychwant
- Dosbarthiad
- Ansawdd
- Allweddeiriau
- System Cyfeirio Gofodol
- Cynnwys
- Cyfyngiadau
- Cynnal a chadw
- Metadata
Dull adnabod
- Dynodydd
- NRW_DS116504
- Teitl Amgen
-
- Laith Metadata
- English
- Datganiad
-
Tray beating was undertaken in dry weather conditions using a gridded white beating tray measuring approximately 25 × 33 cm. Tray beating is a well-established survey technique that involves beating herbaceous fen vegetation over a gridded white plastic tray. At selected locations, this method enabled approximate V. moulinsiana abundance to be estimated, with six tray samples being approximately equivalent to 0.5 m².
In addition, the following information was recorded:
Dominant vegetation types, with particular note made of positive and negative V. moulinsiana habitat suitability indicators (for example, Carex spp. and Glyceria maxima as positive indicators, and Epilobium spp. and Urtica dioica as negative indicators).
Degree of site shading by overhead or overhanging trees and shrubs, recorded as an estimated percentage canopy cover where appropriate, as shading can negatively affect habitat suitability for V. moulinsiana.
Other potentially important environmental and site management factors, including grazing, ground poaching, recent cutting, human trampling, and pheasant release pens.
The presence of other mollusc species.
At four locations, bulk vegetation samples were collected, primarily from the open fen habitat on the western margins of the site. Where V. moulinsiana was recorded, numbers were counted from six-tray samples and converted to approximate densities per square metre, with adult and juvenile snails recorded separately. Twelve-figure GPS grid references and digital photographs were recorded for each principal sample location.
In addition to the formal sampling points, tray beating was undertaken throughout the survey as the surveyor moved around the site in order to identify localised V. moulinsiana populations that might otherwise have been overlooked.
- Gwybodaeth ychwanegol
-
Willing, M.J. 2016 The status of Desmoulin’s Whorl Snail Vertigo moulinsiana at Rhos Goch NNR in 2015. NRW Evidence Report No: 157, 20pp. Natural Resources Wales, Bangor.
- Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
- 2016-03-31
Ystod amser
- Dyddiad cychwyn
- 2015-10-21
- Dyddiad gorffen
- 2015-10-22
- Categori pwnc
-
- Biota
Rhychwant
Rhychwant
- Hyd
- POWYS - POWYS
))
Dosbarthiad
Dosbarthiad
- Fformat - Math a Disgrifiad
-
-
Database
(
Unknown
)
- Math
-
Species records held on the NRW Recorder 6 database.
-
Documents
(
Unknown
)
- Math
-
The final report in Microsoft Word and Adobe PDF formats.
-
Database
(
Unknown
)
Ansawdd
Ansawdd Data
- Cwmpas Ansawdd
- Dataset
- Cydymffurfiad
- 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
- Eglurhad
-
This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
- Gradd
- false
- Datganiad
-
Tray beating was undertaken in dry weather conditions using a gridded white beating tray measuring approximately 25 × 33 cm. Tray beating is a well-established survey technique that involves beating herbaceous fen vegetation over a gridded white plastic tray. At selected locations, this method enabled approximate V. moulinsiana abundance to be estimated, with six tray samples being approximately equivalent to 0.5 m².
In addition, the following information was recorded:
Dominant vegetation types, with particular note made of positive and negative V. moulinsiana habitat suitability indicators (for example, Carex spp. and Glyceria maxima as positive indicators, and Epilobium spp. and Urtica dioica as negative indicators).
Degree of site shading by overhead or overhanging trees and shrubs, recorded as an estimated percentage canopy cover where appropriate, as shading can negatively affect habitat suitability for V. moulinsiana.
Other potentially important environmental and site management factors, including grazing, ground poaching, recent cutting, human trampling, and pheasant release pens.
The presence of other mollusc species.
At four locations, bulk vegetation samples were collected, primarily from the open fen habitat on the western margins of the site. Where V. moulinsiana was recorded, numbers were counted from six-tray samples and converted to approximate densities per square metre, with adult and juvenile snails recorded separately. Twelve-figure GPS grid references and digital photographs were recorded for each principal sample location.
In addition to the formal sampling points, tray beating was undertaken throughout the survey as the surveyor moved around the site in order to identify localised V. moulinsiana populations that might otherwise have been overlooked.
Allweddeiriau
Allweddair
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2008-06-01
Allweddair
-
NRW Thesaurus
-
- snails
- Desmoulin's whorl snail
- vertigo moulinsiana
- Rhos Goch
- Rhos Goch NNR
- Math
- Theme
Dyfyniad
- Dyddiad (Cyhoeddiad)
- 2026-08-27
System Cyfeirio Gofodol
Cynnwys
Gwybodaeth Cynnwys
Proffil CNC
Elfennau CNC
Cyfyngiadau
Cyfyngiadau
Cyfyngiadau ar Fynediad a Defnydd Cyhoeddus
- Math o Gyfyngiad
- Other restrictions
Cyfarwyddeb Cyfyngiadau Mynediad
- Cyfyngiadau
- no limitations
Testun cyfyngiadau mynediad
- Cyfyngiadau eraill
-
There are no access restrictions on this data. NRW may release, publish or disseminate it freely.
Defnyddiwch gyfyngiadau
- Cyfyngiadau Defnyddio
- Other restrictions
- Cyfyngiadau eraill
-
© 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.
Datganiad Priodoli
- Cyfyngiadau eraill
-
Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
Math o Drwydded
- Cyfyngiadau eraill
- Open Government Licence
Metadata
Metadata
- Dynodydd Ffeil
- 4f4c4942-4343-5764-6473-313136353034 XML
- Laith Metadata
- English
- Dynodydd Rhiant
-
Welsh Invertebrate Database (WID)
NRW_DS23774
- Math o adnodd
- Dataset
- Dyddiad Metadata
- 2026-10-07T12:18:46.462Z
- Enw Safonol Metadata
- NRW
- Fersiwn Metadata
-
1.0