For this report, the term 'ecosystem' is based on the typology of habitat types developed for the CORINE biotopes project of the European Communities (Habitat Classification). In this classification, the phytosociological units (plant communities) are organised in a hierarchical system, consisting of eight broad categories, here referred to as 'ecosystem groups'. Each of these groups is sub-divided into numerous subcategories, here referred to as 'habitat types'. These are again divided into more specifically differentiated sub-units and so forth. Each category ecosystem (group), habitat type and their sub-units is characterised by the presence of typical plant and animal species. Currently, however, more is known about plant than about animal communities (Riecken, 1990), so that more emphasis is placed on vegatation.
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