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Intertidal Monitoring of the Dyfi Estuary in Pen Llyn a'r Sarnau Special Area of Conservation (SAC) 2007

The purpose of this data capture was to establish sites for long-term monitoring and collect baseline and reference data using appropriate methods.


Pen Llyn a'r Sarnau Special Area of Conservation is designated for five Annex 1 habitats and four subsidiary. Pen Llyn a'r Sarnau has representative examples of bar-built estuaries in north-west Wales, and includes the Glaslyn/Dwyryd, Mawddach and Dyfi estuaries.

  • Identification
  • Extent
  • Distribution
  • Quality
  • Keywords
  • Spatial Reference System
  • Content
  • Constraints
  • Maintenance
  • Metadata

Identification

Identifier
NRW_DS111184
Alternative Title
  • 2007 CCW/ASML Pen Llyn a'r Sarnau SAC Dyfi Estuary monitoring (MRCCW16300000009)
Metadata Language
English
Lineage

There were three parts to the work:


- In-situ recording of sediment characteristics (including epibiota, infauna and granulometry) at a grid of 106 stations across the whole area of the sediment flats;

- Collection of samples from eleven stations for laboratory analysis of infauna;

- Sediment granulometry and surveys including quadrat recording on three rocky shores.


Modified version of the phase 1 style survey methodology was used. The Grid Maker tool in MapInfo was used to create a grid of 96 stations overlaying existing maps of the Dyfi sediment flats. A single 0.01m2 core sample was taken at each station. This was sieved in a nearby pool and all visible animals were identified and counted. The unrecognisable animals were collected for later inspection under a microscope. Records of conspicuous species and surface sediment features were made from each station within a circle of 1m radius around the core sample position.


In addition to the in-situ recording, core samples were also taken from 11 sites for standard laboratory analysis of macro-infauna and granulometry. Three representative sites along the northern shore were selected for rocky shore surveys. At each, a transect route running down to the shore was divided into zones. The percentage cover of the major species in each zone was recorded, with the presence noted of all other species found. One zone was selected on each shore for sampling with 5 gridded quadrats (0.25 x 0.25 m), with all species present in each quadrat recorded either as percentage cover or as counts. Photographs were taken of each quadrat and each shore zone.


Phase 1 surveys of intertidal habitats in the SAC were carried out between 1999 and 2003 (Brazier et al. 2007), providing detailed mapping of the intertidal biotopes with some information on characterizing species. Confidence in data is high as surveys were carried out by a team of highly experienced intertidal surveyors.

Dataset Reference Date (Publication)
2009-03-01

Temporal Extent

Begin date
2007-08-27
End date
2007-08-31
 
Topic category
  • Biota
Owner
  Natural Resources Wales (NRW) -
Maes-y-Ffynnon, Penrhosgarnedd, Bangor, Gwynedd, LL57 2DW, Wales
http://naturalresources.wales/?lang=en
Originator
  Aquatic Survey and Monitoring Ltd (ASML) -
Whitfield Brow, Bollihope, Frosterley, Weardale, Co. Durham, DL13 2SZ, England
http://www.marineseen.com/aquatic_survey_and_monitoring.htm
 

Extent

Extent

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


 

Vertical Extent

Medin Extent Keyword

benthic boundary layer

 
 

Distribution

Format Type and Description
  • Database ( Marine Recorder Online - Version 2.09.02 )

    Specification

    Marine Recorder

 

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

There were three parts to the work:


- In-situ recording of sediment characteristics (including epibiota, infauna and granulometry) at a grid of 106 stations across the whole area of the sediment flats;

- Collection of samples from eleven stations for laboratory analysis of infauna;

- Sediment granulometry and surveys including quadrat recording on three rocky shores.


Modified version of the phase 1 style survey methodology was used. The Grid Maker tool in MapInfo was used to create a grid of 96 stations overlaying existing maps of the Dyfi sediment flats. A single 0.01m2 core sample was taken at each station. This was sieved in a nearby pool and all visible animals were identified and counted. The unrecognisable animals were collected for later inspection under a microscope. Records of conspicuous species and surface sediment features were made from each station within a circle of 1m radius around the core sample position.


In addition to the in-situ recording, core samples were also taken from 11 sites for standard laboratory analysis of macro-infauna and granulometry. Three representative sites along the northern shore were selected for rocky shore surveys. At each, a transect route running down to the shore was divided into zones. The percentage cover of the major species in each zone was recorded, with the presence noted of all other species found. One zone was selected on each shore for sampling with 5 gridded quadrats (0.25 x 0.25 m), with all species present in each quadrat recorded either as percentage cover or as counts. Photographs were taken of each quadrat and each shore zone.


Phase 1 surveys of intertidal habitats in the SAC were carried out between 1999 and 2003 (Brazier et al. 2007), providing detailed mapping of the intertidal biotopes with some information on characterizing species. Confidence in data is high as surveys were carried out by a team of highly experienced intertidal surveyors.

 

Keywords

Keywords

GEMET - INSPIRE themes, version 1.0
  • Habitats and biotopes
Type
Theme

Citation

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

Keywords

NRW Thesaurus

  • Pen Llyn a'r Sarnau SAC
  • Marine Recorder
  • Mudflats and sandflats
Type
Theme

Citation

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

Keywords

SeaDataNet Parameter Discovery Vocabulary
  • Habitat characterisation
Type
Theme

Citation

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

Spatial Reference System

Code
British National Grid (EPSG::27700)
 

Content

Content Information

NRW Profile

Custom Elements

NRW Related Title

Intertidal monitoring of Pen Llyn a'r Sarnau SAC August 2007

 

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 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

File Identifier
4f4c4942-4343-5764-6473-313131313834 XML
Metadata Language
English
Parent Identifier
Across Wales Intertidal Monitoring Survey

NRW_DS109834

Resource type
Dataset
Metadata Date
2026-10-19T09:42:50.151Z
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

Access the portal
Full access to the portal and metadata.


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