A survey of the spider Agroeca dentigera on Dyfi National Nature Reserve, with a particular focus on Ynylas Dunes (2013-2014)

The sand dune system at Ynyslas, part of Dyfi National Nature Reserve (NNR), supports the only known UK population of the IUCN Vulnerable liocranid spider Agroeca dentigera. Surveys undertaken in 2013 and 2014 sought to determine the species' current status and distribution, following its last confirmed record in 2002, and to improve understanding of its habitat preferences and ecological requirements through targeted surveys of the dune system and other potentially suitable habitats within the NNR.

Identification

Identifier
NRW_DS115894
Alternative Title
Metadata Language
English
Lineage

Sites were surveyed in October 2013, April 2014 and October 2014 using a combination of hand-searching and mechanical sampling techniques. A total of 136 person-hours was devoted to searching potentially suitable habitats across Dyfi NNR. A modified leaf blower was used on one survey occasion to assist sampling.


A single adult female Agroeca dentigera was recorded on 3 October 2014 within an area of dense marram grass in the dune system. Surveys of other potentially suitable habitats did not record the species. Although its habitat preferences remain poorly understood, the available evidence suggests that A. dentigera is associated with dense marram-dominated dune habitat at Dyfi NNR.


In addition to A. dentigera, 94 spider species were recorded, including Philodromus fallax and Ceratinopsis romana. Eleven spider species and a further sixteen non-spider invertebrate species are thought to represent new records for Dyfi NNR. An additional 47 non-spider invertebrate species were also recorded during the surveys.


The considerable survey effort required to locate a single specimen suggests that A. dentigera occurs at very low densities, making the development of effective monitoring protocols challenging. Some voucher specimens have been retained and are held in the collections of Liverpool Museum. The data were provided to NRW for inclusion within Recorder 6, with data transfer underway at the time of reporting.
Dataset Reference Date (Publication)
2015-03-31

Temporal Extent

Begin date
2013-10-01
End date
2014-10-10
 
Topic category
  • Biota
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Originator
  National Museums Liverpool -
National Museums Liverpool, 127 Dale Street, Liverpool, L2 2JH, England
 

Extent

Extent

Geographic Extent
SIR CEREDIGION - CEREDIGION
Geographic Extent
GWYNEDD - GWYNEDD
N
W
E
S
Map representing the geographic extent of the dataset


 
 

Distribution

Distribution

Format Type and Description
  • Database ( Unknown )

    Specification

    Species records on Welsh Invertebrate Database

  • Documents ( https://naturalresources.wales/media/684924/report-054-survey-of-spider-agroeca-dentigera-on-dyfi-nnr.pdf )

    Specification

    Report as pdf format

 

Quality

Data quality

Quality Scope
Dataset
Conformity
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
Explanation

This dataset has not been assessed for conformance to the referenced INSPIRE regulation.
Degree
false
Lineage

Sites were surveyed in October 2013, April 2014 and October 2014 using a combination of hand-searching and mechanical sampling techniques. A total of 136 person-hours was devoted to searching potentially suitable habitats across Dyfi NNR. A modified leaf blower was used on one survey occasion to assist sampling.


A single adult female Agroeca dentigera was recorded on 3 October 2014 within an area of dense marram grass in the dune system. Surveys of other potentially suitable habitats did not record the species. Although its habitat preferences remain poorly understood, the available evidence suggests that A. dentigera is associated with dense marram-dominated dune habitat at Dyfi NNR.


In addition to A. dentigera, 94 spider species were recorded, including Philodromus fallax and Ceratinopsis romana. Eleven spider species and a further sixteen non-spider invertebrate species are thought to represent new records for Dyfi NNR. An additional 47 non-spider invertebrate species were also recorded during the surveys.


The considerable survey effort required to locate a single specimen suggests that A. dentigera occurs at very low densities, making the development of effective monitoring protocols challenging. Some voucher specimens have been retained and are held in the collections of Liverpool Museum. The data were provided to NRW for inclusion within Recorder 6, with data transfer underway at the time of reporting.
 

Keywords

Keywords

GEMET - INSPIRE themes, version 1.0
Type
Theme

Citation

Date (Publication)
2008-06-01
Code
geonetwork.thesaurus.external.theme.httpinspireeceuropaeutheme-theme

Keywords

NRW Thesaurus
  • araneae
  • sand dune ecology
  • RDB spider
  • Ynyslas Dyfi NNR
  • invertebrate surveys
  • spiders
Type
Theme

Citation

Date (Publication)
2026-08-27
Code
geonetwork.thesaurus.local.theme.converted_nrw-keywords
 

Spatial Reference System

Code
British National Grid (EPSG::27700)
 

Content

Content Information

NRW Profile

Custom Elements

NRW Related Title

A survey of the spider agroeca dentigera on Dyfi NNR with a particular focus on Ynyslas Dunes in 2013 and 2014
 

Constraints

Constraints

Limitations on Public Access and Use

Restriction type
Other restrictions
 

Access Constraints Directive

Limitations
no limitations
 

Access Constraints Text

Other constraints

There are no access restrictions to this data. NRW may release, publish or disseminate it freely.
 

Use Constraints

Use constraints type
Other restrictions
Other constraints

© CNC/NRW, 2015. There are no use restrictions on this data. Recipients may re-use, reproduce, disseminate this data free of charge in any format or medium, provided they do so accurately, acknowledging both the source and NRW's copyright, and do not use it in a misleading context. It is the recipient's responsibility to ensure the data is fit for the intended purpose, that dissemination or publishing does not result in duplication, and that it is fairly interpreted. Advice on interpretation should be sought where required. To avoid re-using old data, users should periodically obtain the latest version from the original source.
 

Attribution Statement

Other constraints

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved.
 

Licence

Other constraints
Open Government Licence
 
 
 

Metadata

Metadata

File Identifier
4f4c4942-4343-5764-6473-313135383934 XML
Metadata Language
English
Resource type
Dataset
Metadata Date
2026-10-07T14:24:51.251Z
Metadata Standard Name
NRW
Metadata Standard Version

1.0

pointOfContact
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
 
 

Publishing Body

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