Summary of habitat loss - saltmarsh

In Great Britain an area almost equivalent to the extent of saltmarsh present in the late 1980s (43,000ha) may have been enclosed in the last 300 years or so, much of it for for agricultural use. In France, during the 1900s over half the saltmarsh of western France were enclosed (Géhu 1984). Géhu further reports 'Almost all saltmarshes in France suffer from deterioration and 'nibbling'' a process whereby small scale enclosure, including dumping of rubbish slowly excludes the tide. In the Mediterranean saltmarshes declined rapidly after the 1930's because of their extensive enclosure and conversion for cultivation (Goutner 1992).

It is difficult to estimate the total area of intertidal land claimed from the sea, though a majority of estuaries and deltas in Europe show evidence of such activity. In the Netherlands the area amounts to as much as 40% of the total land surface of the country, a large proportion of which is used for agriculture. Here schemes involved both tidal flats and saltmarsh. 'Reclamation' of the Zuyder Zee, covered a total of 550,000ha; enclosed between 1920-1925. Throughout the last century enclosure continued in The Wadden Sea and south west Holland (See Table below, summarised from Dijkema 1984).

More recent losses through erosion have been identified in south east England, which appear to be partly the result of sea level rise. When combined with the inability of the saltmarsh to move landward because of presence of artificial or other barriers 'saltmarsh squeeze' occurs.

References

Dijkema, K.S. 1984. Saltmarshes in Europe. Nature and Environment Series, 30 Council of Europe, Strasbourg.

Géhu, J.M. 1984. 'Saltmarsh loss' Southern Europe. Saltmarshes in Europe

Goutner, V. 1992. Management of Mediterranean Lagoons and Saltmarshes. Abstracts of Papers to the Medmaravis Conference, Chios, Greece Medmaravis.