Changes in the extent of the Thames Estuary grazing marshes

Coastal grazing marsh is flat, low lying pasture which has been reclaimed from tidal salt marsh by the construction of sea walls. The Thames Estuary grazing marshes are known for the occurrence of nationally uncommon plants and invertabrates, and their ability to support nationally significant populations of breeding and wintering birds. In view of the importance of the Thames Estuary grazing marsh for nature conservation, a study was initiated to examine changes in extent of the habitat and the prevailing land use pressures. Historical data sources were used to estimate and map the extent of grazing marsh in 1935, 1968, 1972 and 1981. Field survey was undertaken in 1989 to provide up-to-date data.