The dataset details global positioning system (GPS) locations recorded for survey quadrats at six UK saltmarsh sites. Three of the sites were in Morecambe Bay, North West England and three of the sites were in Essex, South East England, each of these sites consisted of a salt marsh area and adjacent mudflat area. Each site comprised 22 quadrats on the unvegetated mudflat and 22 quadrats on the salt marsh. The locations indicated by this dataset correspond to the south-east corner of the quadrats which were 1m square and oriented with their sides aligned North-South and East-West.
We combined spatial data relating to the environs of the study sites from a number of sources (Ordnance Survey Digital Terrain Models, Ordnance Survey Boundary Line, Environment Agency Saltmarsh Extents, Natural England Priority Habitat Inventory). These were rasterised and quadrat values were extracted on a pointwise basis for elevation and proximity (distance to creek, habitat edge and high water mark). Tidal height was calculated with reference to the relevant Tidal Gauge and Admiralty Standard Port information.
This data was derived as part of Coastal Biodiversity and Ecosystem Service Sustainability (CBESS): NE/J015644/1. The project was funded with support from the Biodiversity and Ecosystem Service Sustainability (BESS) programme. BESS is a six-year programme (2011-2017) funded by the UK Natural Environment Research Council (NERC) and the Biotechnology and Biological Sciences Research Council (BBSRC) as part of the UK's Living with Environmental Change (LWEC) programme.
Publication date: 2016-06-16
Quadrat locations were taken from GPS readings collected during the CBESS survey programme (OSGB coordinates). Rasterised Digital Terrain Model data at 5 and 50 m horizontal resolution was downloaded from Edina Digimap (Edina.ac.uk), and elevation values at quadrat locations were extracted using R (www.r-project.org; Raster/Maptools packages). Tidal range at relevant Admiralty Standard Ports and adjustment applicable at relevant local tidal gauge were identified, and Mean Low Water Springs and Mean High Water Springs were converted to Ordnance Datum. Tidal height (elevation relative to the difference between Mean Low Water Springs and Mean High Water Springs) was computed at each quadrat for GPS and DTM derived elevations.
Saltmarsh and mudflat boundary data were downloaded from the Environment Agency and Natural England Priority Habitats Inventory. Mean High Water line was extracted from Ordnance Survey Boundary Line data, and land edge from Ordnance Survey Vector Map data. Line shapefiles were converted to rasters with 5 and 50 m horizontal resolution (matching OS DTM grid) using R. Distance to creek edge and high water line (saltmarsh only), and land edge (mudflat only) was calculated in R using 5 m resolution rasterised shapefiles.