The Forest Steppe Dynamics in the Carpathian Basin

The Carpathian Basin belongs to the regions of Europe with the highest biodiversity (Williams et al. 1999). Due to its transitional position during the Quaternary climatic fluctuations, the overlap and accumulation of floristic and faunistic elements of contrasting habitats occurred here. This overlapping of different climatic provinces, enhanced by the varied relief, edaphic and hydrographic conditions, has resulted in suitable conditions for the survival of a large number of species belonging to different core areas and displaying various patterns of longdistance and short-distance re-populations.

It is typical for South-Eastern Central Europe that the large-scaled zonal settling of vegetation, characteristically developed in the East-European table-land, breaks down. In the Carpathian Basin, the concentric arrangement of vegetation belts is influenced by numerous climatic, orographic, hydrographic and edaphic factors (Varga 1995, 2003b). The forest-steppe, which is typical in the major, central lowland and hilly parts of the basin, is represented by a number of regional variants showing distinct geological, edaphic and meso-climatic characters. The forest, skirt and grassland compartments of each regional variant of the forest-steppe are highly intercorrelated. The Carpathians transmit (e.g. boreal) also filter certain different (e.g. steppic) biogeographical influences. Populations passing through the Carpathians will often be isolated and differentiated from the populations inhabiting other parts of their range of distribution.

The geographically transitional position of the Carpathian Basin resulted in a conspicuous mixture of faunal elements of diverse origins and geographical histories. The compartment structure of the vegetation complexes, typical for the Pannonian forest-steppe, has promoted the survival of very different faunal elements. Especially, the hilly areas of transitional climatic conditions surrounding the Pannonian lowland are populated by numerous, biogeographically important species and communities. The Southern, xerothermic slopes and foothills of the Hungarian Middle Range served both as refuges for thermo-xerophilous elements during several cold and cool-humid climatic phases of the Quaternary and as centres of their dispersal (Soo 1940, 1959; Wendelberger 1954, 1959; Zolyomi 1949, 1953, 1964). Thus, many thermophilous elements probably populated the Carpathian Basin not only by long-distance colonisation from remote, large glacial refuges, but also from numerous meso- or microclimatically favourable sites lying at the fluctuating borderlines of the Mediterranean refugial and periglacial belts. The varied and fine biostratigraphical structure of the Hungarian young Pleistocene, often characterised by a coexistence of forest and non-forest faunal elements (e.g. Janossy 1979; Kordos 1977; Kretzoi 1969, 1977), provides evidences to support this view and demonstrates the transitional biogeographical character of this region during the whole time-span of the Quaternary period. New palynological data from the Eastern part of the Pannonian lowland (Batorliget) also suggest the presence of forest refuges during the last glacial period (see also: 3.2.).

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