The general environmental characteristics of West European coastal dunes and those of salt marshes are outlined. It is pointed out that the dynamical character of the dune system with its interaction between plants and sand in building and degeneration phases has been known for a much longer period of time than generally believed.
As to the salt marshes the special significance is discussed of ungrazed marshes; the majority of the marshes having been under a grazing regime for a long time is elucidated.
The distinction between internal management is mentioned, i.e. the measures taken to maintain or improve the qualities of an area, versus external management, i.e. the measures to prevent or counteract negative influences from outside the area.
Structure and function of coastal areas
Coastal areas are a major concern of nature conservation. As a narrow ecocline between two extremely contrasting biochores, sea and land, they represent a high ecological interest. At the same time, however, they are most threatened by human u s e .
Previously, the main general functions of coastal areas were two-fold: (1) communication with the oversea world, (2) hunting, fishing and seafood cropping. Regionally other functions may have preponderated; in the Low Countries the coastal zone defends the hinterland against the sea, whereas in barren areas like western Ireland it constitutes, of old, the main settlement ground. However, in general these activities did not imply a major pressure on the ecological qualities of the area. For centuries, human beings have settled at the head of deltas and estuaries and expanded cropping and * Nomenclature follows Heukels & Van Ooststroom (1977).