Quantifying the Status of Great Crested Newts (Triturus cristatus) in Wales (2014)
The Great Crested Newt (Triturus cristatus) is declining in the United Kingdom despite full European-level protection. Reporting on the species status to the EU is carried out at UK level but nature conservation is a devolved function. Knowledge and quantification of the Great Crested Newts status in Wales will therefore forms part of future UK wide reporting. The purpose of this GIS based dataset was to: (i) Demonstrate the applicability of GIS techniques to quantification of conservation status parameters and predictive mapping; and, (ii) Produce regional, fine-scale spatial outputs (at 25 m resolution) which could be aggregated to create an objective quantification of spatial metrics for the Great Crested Newt across Wales. Combined model outputs were good to excellent (AUC 0.71 to 0.86) and successfully quantified range (7,312 km squared), population (3,271 occupied ponds) and habitat (2,2170 km squared) parameters, as well as suggesting a proxy quantification for habitat quality (810 high quality ponds). Article 17 reporting is based on quantification of four parameters: range, population, habitat for the species, and future prospects. Range: The defined range for the great crested newt in Wales is calculated using a convex hull algorithm in the R statistical software. The input data consisted of a collection of all known presence locations. The alpha value used was 8,000, arrived at by trialling several values and selecting the one most representative of the observed core distribution in Wales. Population: Population is number of populations, equating to number of occupied ponds. To determine this number for Wales, the EQSS threshold for each model was used to determine the areas in which suitable ponds might be found. The suitable habitat was then clipped to the known range of the species in Wales and subsequently used to clip a UK wide pond dataset, extracted from Mastermap. Habitat for the species: The EQSS outputs were converted into polygons, from which total area in km squared was derived. This area was then clipped to the known range of Great Crested Newts in Wales to provide an estimate of the suitable habitat available to the species within their range. Future Prospects: It theoretically includes all factors potentially impacting great crested newts at sites and/or larger scales including (but not limited to) legislation, climate or site-specific factors. The UKs latest Article 17 report for the great crested newt lists Future Prospects as unknown. With application of the modelling processes described in the present report to Scotland and regions of England, confidence in habitat and population metrics could be improved to allow a UK-wide assessment of Future Prospects.
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Identification
- Identifier
- NRW_DS115877
- Alternative Title
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- Mesur Statws y Fadfall Gribog yng Nghymru (2014)
- Metadata Language
- English
- Lineage
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This dataset combines GIS model outputs from previous studies for Anglesey and North East Wales, Powys and Brecon Beacons National Park, and South Wales (Gower to Monmouthshire) to derive robust, repeatable Great Crested Newt status metrics for the species across its distribution in Wales. Most Great Crested Newts record data collected by volunteers, but this analysis carried out by professional ecologists so confidence in this dataset is overall high. Fine-scale GIS outputs specifically to inform Great Crested Newt status in Wales were generated from Maximum Entropy Modelling (MaxEnt; also known as Multinomial Logistic Regression) for (i) Anglesey (ii) North East Wales (Flintshire, Denbighshire and Wrexham), (iii) Powys and Brecon Beacons National Park and (iv) South Wales (Gower Peninsula to Monmouthshire). These four areas, delimited by modern Welsh unitary authority boundaries, encompass the overwhelming majority of the natural range of Great Crested Newts in the country. The present study describes the aggregation of model outputs, and the generation of accurate and objective all-Wales status metrics which can be repeated to assess possible status changes in Wales, and could be applied to other regions and countries of the UK. Combining model outputs: The Equal Training Sensitivity and Specificity (EQSS) threshold was used to delineate areas of suitable Great Crested Newt habitat. Final combined outputs were clipped by the boundary of Wales for display and calculation purposes.
- Dataset Reference Date (Publication)
- 2014-07-31
Extent
Extent
- Geographic Extent
- Wales (WLS)
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Distribution
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Documents
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[A] A pdf of the report is available in Ffynnon: NRW-15-014399 [B] Raw data for modelling is held by the ARC Trust
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Documents
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Quality
Data quality
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This dataset combines GIS model outputs from previous studies for Anglesey and North East Wales, Powys and Brecon Beacons National Park, and South Wales (Gower to Monmouthshire) to derive robust, repeatable Great Crested Newt status metrics for the species across its distribution in Wales. Most Great Crested Newts record data collected by volunteers, but this analysis carried out by professional ecologists so confidence in this dataset is overall high. Fine-scale GIS outputs specifically to inform Great Crested Newt status in Wales were generated from Maximum Entropy Modelling (MaxEnt; also known as Multinomial Logistic Regression) for (i) Anglesey (ii) North East Wales (Flintshire, Denbighshire and Wrexham), (iii) Powys and Brecon Beacons National Park and (iv) South Wales (Gower Peninsula to Monmouthshire). These four areas, delimited by modern Welsh unitary authority boundaries, encompass the overwhelming majority of the natural range of Great Crested Newts in the country. The present study describes the aggregation of model outputs, and the generation of accurate and objective all-Wales status metrics which can be repeated to assess possible status changes in Wales, and could be applied to other regions and countries of the UK. Combining model outputs: The Equal Training Sensitivity and Specificity (EQSS) threshold was used to delineate areas of suitable Great Crested Newt habitat. Final combined outputs were clipped by the boundary of Wales for display and calculation purposes.
Keywords
Keywords
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Citation
- Date (Publication)
- 2008-06-01
Keywords
- NRW Thesaurus
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- great crested newts
- triturus cristatus
- protected species
- modelling
- Favourable Conservation Status (favourable condition)
- ecological connectivity
- Type
- Theme
Citation
- Date (Publication)
- 2023-12-31
Spatial Reference System
Content
Content Information
NRW Profile
Custom Elements
Constraints
Constraints
Limitations on Public Access and Use
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Access Constraints Directive
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- no limitations
Access Constraints Text
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The raw datasets associated with the model outputs are wholly owned by Amphibian and Reptile Conservation Trust. NRW does not hold a copy of the data; enquirers are advised to obtain a copy from the owner/originator directly, rather than NRW. NRW may NOT publish or disseminate it in its entirety. The model output screen shots held within the report Quantifying the Status of Great Crested Newts in Wales. French GCA, Wilkinson JW, Fletcher DH, and Arnell AP. 2014. NRW Science Report 31, are wholly owned by NRW. There are no access restrictions on these screenshots. NRW may release, publish or disseminate these freely.
Use Constraints
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© Amphibian and Reptile Conservation Trust, 2014. NRW does NOT grant permission to third parties to re-use or disseminate the raw dataset. Those seeking such permission should approach the originator directly. However the following applies to the model outputs and screen shots held within the report Quantifying the Status of Great Crested Newts in Wales.French GCA, Wilkinson JW, Fletcher DH, and Arnell AP. 2014. NRW Science Report 31. © CNC/NRW, 2014. There are no use restrictions on these screen shots. 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.
Metadata
Metadata
- File Identifier
- 4f4c4942-4343-5764-6473-313135383737 XML
- Metadata Language
- English
- Resource type
- Dataset
- Metadata Date
- 2024-05-31T09:42:53.161Z
- Metadata Standard Name
- NRW
- Metadata Standard Version
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1.0