Intertidal Monitoring of Eelgrass (Zostera marina) Extent and Density in Pen Llŷn a'r Sarnau Special Area of Conservation (SAC), 2004
Monitro Rhynglanwol Ehangder a Dwysedd Morwellt (Zostera marina) yn Ardal Cadwraeth Arbennig (ACA) Pen Llŷn a'r Sarnau, 2004

  • English
  • wel
  • All

A survey was undertaken in 2004 to map and assess the extent and density of intertidal eelgrass (Zostera marina) beds within the Pen Llŷn a'r Sarnau Special Area of Conservation (SAC). Seagrass beds occur in intertidal and shallow subtidal areas on sandy and muddy sediments in sheltered coastal environments and are recognised for their ecological and economic importance. Zostera marina is protected under the EC Habitats Directive and is recognised as a UK Biodiversity Action Plan Priority Habitat. Seagrass meadows provide nursery areas for juvenile fish, feeding grounds for wildfowl including Brent geese, and contribute to sediment stabilisation, coastal defence and erosion reduction.


The purpose of the survey was to map the current known intertidal extent of the Zostera biotope and develop a methodology for assessing seagrass density. The survey established a baseline dataset describing the distribution and density of eelgrass beds within the SAC, supporting future monitoring of their conservation status and vulnerability to human pressures such as pollution, dredging and boat moorings.

Identification

Dynodydd
Identifier
NRW_DS102010
Teitl Amgen
Alternative Title
  • 2004 CCW / IECS Pen Llyn a'r Sarnau SAC Zostera marina monitoring (MRCCW3020000000D)
Laith Metadata
Metadata Language
English
Lineage

Under the Habitats Directive, CCW is required to assess the conservation status of SAC features on a regular basis. Zostera marina beds had previously been mapped during the intertidal Phase 1 survey undertaken in 1997, and the Institute of Estuarine and Coastal Studies (IECS) was contracted by CCW to undertake follow-up monitoring.


The extent of eelgrass beds was mapped on foot by walking the perimeter of the biotope and recording boundary positions using a portable differential GPS system. Representative photographs were taken throughout the survey. Seagrass density was assessed using twelve randomly selected sampling stations, each covering 0.07 m². At each station, the number of blades/leaves present was counted and used to calculate blade density per square metre. Differential GPS positions were recorded for every sampling location. The resulting dataset provides a baseline measure of eelgrass extent and density for future monitoring and condition assessment.
Additional Information

Boyes, Hemingway, Allen (2008) Intertidal monitoring of Zostera marina in Pen Llyn a'r Sarnau SAC in 2004/2005. CCW Marine Monitoring Report No 28.
Dyddiad cyfeirnod y set ddata (Cyhoeddiad)
Dataset Reference Date (Publication)
2008-12-31

Temporal Extent

Begin date
2004-07-06
End date
2005-08-07
 
Categori pwnc
Topic category
  • Biota
    Biota
Perchennog
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Cychwynnwr
Originator
  Countryside Council for Wales (CCW) -
Countryside Council for Wales, Maes y Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW
http://naturalresourceswales.gov.uk/splash?orig=/
 

Extent

Extent

Hyd
Geographic Extent
Wales (WLS)
N
W
E
S
Map representing the geographic extent of the dataset


 

Vertical Extent

Medin Extent Keyword
littoral
 
 

Distribution

Fformat - Math a Disgrifiad
Format Type and Description
  • Database ( Marine Recorder Online - Version 2.09.02 )

    Specification

    Marine Recorder

 

Quality

Ansawdd Data
Data quality

Cwmpas Ansawdd
Quality Scope
Dataset
Dataset
Cydymffurfiad
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

Under the Habitats Directive, CCW is required to assess the conservation status of SAC features on a regular basis. Zostera marina beds had previously been mapped during the intertidal Phase 1 survey undertaken in 1997, and the Institute of Estuarine and Coastal Studies (IECS) was contracted by CCW to undertake follow-up monitoring.


The extent of eelgrass beds was mapped on foot by walking the perimeter of the biotope and recording boundary positions using a portable differential GPS system. Representative photographs were taken throughout the survey. Seagrass density was assessed using twelve randomly selected sampling stations, each covering 0.07 m². At each station, the number of blades/leaves present was counted and used to calculate blade density per square metre. Differential GPS positions were recorded for every sampling location. The resulting dataset provides a baseline measure of eelgrass extent and density for future monitoring and condition assessment.
 

Keywords

Allweddair
Keywords

GEMET - INSPIRE themes, version 1.0
Math
Type
Theme
Theme

Dyfyniad
Citation

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

Allweddair
Keywords

NRW Thesaurus
  • Pen Llyn a'r Sarnau SAC
  • Marine Recorder
  • Zostera bed, extent quadrats
Math
Type
Theme
Theme

Dyfyniad
Citation

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

Allweddair
Keywords

SeaDataNet Parameter Discovery Vocabulary
Math
Type
Theme
Theme

Dyfyniad
Citation

Dyddiad (Cyhoeddiad)
Date (Publication)
2024-06-19
Code
geonetwork.thesaurus.external.theme.rdf+xml
 

Spatial Reference System

Code
WGS 84 (EPSG:4326)
 

Content

Gwybodaeth Cynnwys
Content Information

Proffil CNC
NRW Profile

Elfennau CNC
Custom Elements

NRW Related Title

Intertidal Monitoring of Zostera marina in Pen Llyn a'r Sarnau SAC in 2004/2005
 

Constraints

Constraints

Limitations on Public Access and Use

Math o Gyfyngiad
Restriction type
Other restrictions
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

Cyfyngiadau Defnyddio
Use constraints type
Other restrictions
Other restrictions
Other constraints

© 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.
 

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

Dynodydd Ffeil
File Identifier
4f4c4942-4343-5764-6473-313032303130 XML
Laith Metadata
Metadata Language
English
Parent Identifier
Across Wales Intertidal Monitoring Survey

NRW_DS109834
Math o adnodd
Resource type
Dataset
Dataset
Dyddiad Metadata
Metadata Date
2026-10-19T08:04:14.449Z
Enw Safonol Metadata
Metadata Standard Name
NRW
Fersiwn Metadata
Metadata Standard Version

1.0

Pwynt Cyswllt
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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