Change in saltmarsh extent for six regions across Great Britain (1846-2016)

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https://doi.org/10.5285/03b62fd0-41e2-4355-9a06-1697117f0717

Data are presented showing change in saltmarsh extent along 25 estuaries/embayments in six regions across Great Britain, between 1846 and 2016. Data were captured from maps and aerial photographs. Marsh extent was delineated a scale of 1:7,500 by placing vertices every 5 m along the marsh edge. Error introduced from: (i) inaccuracies in the basemap used to georeference maps and aerial photographs; (ii) the georeferencing procedure itself; (iii) the interpreter when placing vertices on the marsh edge; and (iv) map and photo distortions that occurred prior to digitisation were calculated and used to estimate the root mean square error (RMSE) in areal extent of each marsh complex. Measures of marsh extent were only recorded if maps and aerial photographs were available for the entire estuary/embayment. Data was collected as part of a study on the large-scale, long-term trends and causes of lateral saltmarsh change. The data was used in the analysis for Ladd et al. (2019). C. Ladd and M.F. Duggan-Edwards carried out the collection and processing of the saltmarsh extent data. All authors contributed to the interpretation of the data.

The work was carried out under the NERC programme - Carbon Storage in Intertidal Environment (C-SIDE), NERC grant reference NE/R010846/1.

Publication date: 2019-09-18

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Format

Shapefile

Spatial information

Study area

Spatial representation type

Vector

Spatial reference system

OSGB 1936 / British National Grid

Temporal information

Temporal extent

1846-06-01 to 2016-05-26

Provenance & quality

The aerial extent change in saltmarsh extent across Great Britain came into existence by using Ordnance Survey (OS) maps and aerial photographs to delineate marsh extent for each estuary.. Marsh extent was delineated in ArcGIS 10.6 at a scale of 1:7,500 by placing vertices every 5m along the marsh edge. A Root Mean Square Error (RMSE) term (in meters) was calculated for each marsh complex by assessing error introduced by: (i) inaccuracies in the basemap used to georeference maps and aerial photographs; (ii) the georeferencing procedure itself; (iii) the interpreter when placing vertices on the marsh edge; and (iv) map and photo distortions that occurred prior to digitisation. To qualitatively assess whether the vectorised layer could be considered accurate, the most recent digitised marsh extent was compared against national marsh extent layers to ensure general agreement. Literature searches were also done to verify whether observations of significant change in marsh extent were reliable, or whether errors introduced by map surveyors on the location of the marsh edge likely explain the differences.

Licensing and constraints

This dataset is available under the terms of the Open Government Licence

Cite this dataset as:

Ladd, C.J.T.; Duggan-Edwards, M.F.; Bouma, T.J.; Pagès, J.F.; Skov, M.W. (2019). Change in saltmarsh extent for six regions across Great Britain (1846-2016). NERC Environmental Information Data Centre. https://doi.org/10.5285/03b62fd0-41e2-4355-9a06-1697117f0717

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Services associated with this dataset

WMS for Change in saltmarsh extent for six regions across Great Britain (1846-2016)

This dataset is included in the following collections

Sedimentological, ecological and physical data collected from UK saltmarsh sites by the Carbon Storage in Intertidal Environments (C-SIDE) project

Citations

Ladd, C.J.T., Duggan‐Edwards, M.F., Bouma, T.J., Pagès, J.F., & Skov, M.W. (2019). Sediment supply explains long‐term and large‐scale patterns in saltmarsh lateral expansion and erosion. Geophysical Research Letters. https://doi.org/10.1029/2019GL083315

de la Barra, P., Skov, M., Lawrence, P., Schiaffi, J., & Hiddink, J. (2022). Tidal water exchange drives fish and crustacean abundances in salt marshes. Marine Ecology Progress Series, 694, 61-72. https://doi.org/10.3354/meps14118