Coastal and Floodplain Grazing Marsh

Grazing marsh is periodically inundated pasture, or meadow with ditches that maintain the water levels, containing standing brackish or fresh water. Sites may contain seasonal water-filled hollows and permanent ponds with emergent swamp communities.

Grazing Marsh at Pevensey Levels

Photo: Peter Wakely/Natural England

Why is it important?

  • Wading birds such as Redshank feed on invertebrates forced close to the surface by the high water table and shallow surface floods.
  • Around 500 species of vascular plant have been recorded from grazing marsh including rare species such as Narrow-leaved Water-dropwort.
  • It supports large numbers of invertebrates including over a thousand nationally notable species.
  • Drainage channels and open water associated with grazing marsh support a number of fish species and can provide important spawning areas.
  • Water filled ditches are often used by Otter, Water Vole, and various dragonflies.

Coastal and Floodplain Grazing Marsh in Sussex

Sussex has around 11400 hectares of grazing marsh, with the rivers Arun, Adur, Ouse and Cuckmere all having important areas. Just under half of Sussex’s floodplains consist of wet grassland, however much of this has been agriculturally improved decreasing its value for wildlife. Pevensey Levels is one of only three sites in Britain where the large Fen Raft Spider is found, and two rare species of ramshorn snail can also be found in Sussex.

What are the threats?

  • Conversion to agriculture through drainage and fertilizer application.
  • Drainage and flood defences can disrupt the hydrology of sites.
  • Overgrazing, neglect or early grazing, can affect breeding birds.
  • Water pollution, which can be exacerbated if concentrated by over-abstraction.
  • Floodplain development, aggregate extraction and recreational pressure.
  • Isolation and fragmentation of sites reduces dispersal opportunities making species more susceptible to extinction.

Some associated species

  • Lapwing Vanellus vanellus
  • Merlin Falco columbarius
  • Marsh Mallow Moth Hydraecia osseola
  • Desmoulin’s Whorl Snail Vertigo moulinsiana
  • Greater Water Parsnip Sium latifolium
  • Star Sedge Carex echinata


Photo: Paul Stevens

Advice on coastal and floodplain grazing marsh

After Minerals
Floodplain Meadows Partnership
Sussex Wetland Landscapes Project
The Grasslands Trust
The Grazing Advice Partnership

Sussex Targets

Biodiversity Action Reporting System Website