The Ecological Significance of Embankment and Drainage with Respect to the Vegetation of the South-West Netherlands

Abstract

Former embanking and draining activities are closely associated with natural geomorphological components and tidal processes inherent in the water-land boundary. These components, named selectors by van Leeuwen (1967), appeared to help man in selecting his own environment. The ecological side-effects of embanking and drainage are both nagative and positive. The nagative side-effects are apparent mainly outside the sea-dike and the positive ones in the polderland. The dike itself forms a special habitat as a pathway for immigration. Both types of side-effects are discussed in their connection with embankment and drainage works as well as in their ecological consequences for plant life (especially that of halophytes). The problems of river fluke disease and of the distribution of some other animal groups are briefly mentioned. A plea is made for an evaluation of the real economic advantage of such coastal engineering works against the social advantages of the present state of the coast''s natural features.