Nicola Arndt und Matthias Pohl - Neobiota
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Nicola Arndt und Matthias Pohl - Neobiota

Nicola Arndt und Matthias Pohl - Neobiota Nicola Arndt und Matthias Pohl - Neobiota

neobiota.net
22.02.2013 Aufrufe

Figure 1: The ecoregions are categorized within 14 biomes and eight biogeographic realms to facilitate representation analyses. 74 Figure 2: The map of terrestrial ecoregions of the world recognizes 825 distinct units.

While the delineation of appropriate ecoregions was relatively simple in some regions, other areas required an examination of the influence of historic events on present day distributions. The Philip- pines archipelago is an example of a region where Pleistocene sea level changes and resulting appearance and disappearance of land bridges had important implications for the resulting pattern of animal distributions among the islands (HEANEY 1986, 1991). Large-scale ecological and physical dynamics and processes have been emphasized, including major variations in climate, fire disturbance regimes, and large vertebrate migrations (RICKETTS et al. 1999). Consequently, delineation of ecoregions differed between tropical regions and boreal or polar habitats where species assemblages are relatively homogeneous across large regions. Ecoregions are intended to distinguish distinct biotas, yet distribution data for whole biotas are incom- plete and no single biogeographic framework is optimal for all taxa. Thus, ecoregions represent a compromise map for the distribution of many different taxa. Ecoregions are also represented on maps as having abrupt boundaries, however, in reality most ecoregions are separated by ecotones and mo- saic habitats. Finally, most ecoregions contain subsidiary habitats that may differ from their nominal biome, such as small edaphic savannas found within the widespread lowland forest of the Amazonian ecoregion. More detailed biogeographic analyses will always be required to ensure recognition and protection of less dominant habitat types and special elements that occur within the larger ecoregions. 3 Delineating the European ecoregional boundaries The western Palearctic ecoregions (except northern Africa) were developed in concert with the DMEER (2000) project, using the Map of the Natural Vegetation of Europe (BOHN et al. 2000) as a basis. A variety of systems were reviewed prior to the delineation of European ecoregions. KÜCHLER’s (1954) Natural Vegetation map was used as a guide to aggregate BOHN et al.’s (2000) mapping units into larger biogeographic divisions, generally at the level of KÜCHLER’s main formations. However, these groupings were modified by other biogeographic criteria, including discrete montane or island areas that were assumed to support concentrations of endemic species. The European Environmental Agency (EEA) and the European Topic Centre on Nature Conservation (ETC/NC) were working on a similar Digital Map of European Ecological Regions (DMEER) at the same time. The DMEER effort is intended to become a widespread and widely accepted reporting and assessment framework for biodiversity and nature patterns such as fauna, flora, habitats and landscapes. The DMEER effort is a combination of the Map of Natural Vegetation of Europe (BOHN et al. 2000) developed by the Federal Agency for Nature Conservation (BfN, Germany) and a cluster analysis of European-wide climatological data known as the European Land Classification (BUNCE 1985, BUNCE et al. 1996) developed by the Institute of Terrestrial Ecology (ITE, UK). The EEA, ETC/NC and WWF share a common goal of developing compatible systems of ecological and biogeographic regions for Europe. Similar systems will facilitate conservation planning, monitoring of biodiversity, and communication. This shared philosophy made necessary a series of compromises from both initiatives, negotiated through several exchanges, primarily a joint EEA workshop with WWF hosted at ETC/NC in Paris in August 1999 and an additional meeting at the FAO-FRA 2000 conference at the World Conservation Monitoring Centre in Cambridge. Through these efforts, the WWF ecoregion map now closely matches the DMEER ecological regions map, with the WWF map resolving a few areas in greater detail. 75

Figure 1: The ecoregions are categorized within 14 biomes and eight biogeographic realms to facilitate representation<br />

analyses.<br />

74<br />

Figure 2: The map of terrestrial ecoregions of the world recognizes 825 distinct units.

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