| Particular coastal habitats are more prevalent in particular coastal landscapes. European seagrass beds, for example, can only be found on unconsolidated sediments, and stands of macro-algal kelp are abundant on hard rocks. From this tabulation, the most important habitats will subsequently be identified for the different European coastal seas, i.e. the Atlantic sea board, the Baltic Sea, the North Sea, the Mediterranean and the Black Sea. This breakdown by seas is then used to briefly sketch natural dynamics and downscale drivers for change and their effects to specific habitats.
The tabulation of habitat types (Table 2(b) - previous page) suggests that a distinction in hard-rock versus sedimentary coastlines has been very useful in identifying clusters of predominant habitats. Also, several habitats have rather similar patterns of occurrence across landscapes, hence probably often occur together. Examples are mudflats and sandbars, cliffs and shingle bars, as well as wetland and dune systems. This has a direct geomorphological/geo-genetical basis. The distribution of seagrass beds over the different landscape types in the table is not very distinct. Apparently, seagrass beds may occur along many coasts, which is confirmed in older literature (e.g. Den Hartog, 1970) and on recent, internet-available GIS databases (see for example http://stort.unep-wcmc.org/imaps/marine/seagrass/viewer.htm).
Homogeneity
The degree to which items are similar.
See Glossary for complete list of all terms. |
Three further aspects need to be highlighted. Firstly, the pelagic and deep sea sediments of the open sea have been omitted from the typology, but can be added easily. The newer EUNIS-typology does include these habitats. Secondly, habitat types differ in their degree of homogeneity and spatial extent. Estuaries and lagoons, for example, appear to be rather generic and actually may comprise complexes of different, more homogeneous habitat types. Thirdly, a number of habitat qualifyers in the header row also appear in the landscape column. Apparently, some landscapes have been considered to be dominated by a particular habitat. Overall, this apparent inconsistency is a consequence of asymmetric spatial heterogeneity at various spatial scales that has been ignored in the typology, probably for practical reasons.
Generic
Applicable to an entire class or group; belonging to the same main group.
See Glossary for complete list of all terms. |
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