Abstract
Boundaries of geographical ranges are often packing in some parts of the Carpathian basin. Furthermore, ranges of allo/parapatric sister species/subspecies often overlap or contact here. Marginal populations of numerous species occur here in different dynamic states, like partly relict-like, retreating, partly expanding or even hybridising with parapatric sister taxa. We selected different cases of range edges and marginal overlaps in different large taxonomical groups of animals: Orthoptera, Lepidoptera, Amphibia and Reptilia. Recent palaeoecological surveys have demonstrated the 'double refugial effect' in some regions of the Carpathian basin which were suitable for conservation of 'rear edge' populations during the cold climatic periods including the smaller climatic fluctuations within the major glacial cycles. We consider that we could identify as extra-Mediterranean refugia even those areas where 'rear edge' populations could survive the LGM period. Based on these general considerations a four-step research programme can be outlined: 1. Palaeo-ecological reconstruction and modelling of LGM ranges of species which have recent range edges in the Carpathian basin. Comparative phylogeography of faunal types with packing edges of distribution. 2. Reconstruction of the coalescence time in species with genetically divergent populations and/or 'phylogeographic rendezvous' with or without hybridisation in the Carpathian basin. 3. Reconstruction of bottleneck vs. population growth periods of these species in connection with the palaeo-environmental changes. 4. Prediction of the possible reactions of species with range edges and/or hybrid zones in the Carpathian basin on climatic change scenarios. Which are the probable reactions of their marginal populations, and the chances for survival in a 'traditional' vs 'modern' cultural landscape? Comparative aspects of phylogeographic patterns and processes will be elaborated connected with very recent developments concerning the nested structures within refugia ('refugia within refugia', micro-refugia) and extra-Mediterranean (cryptic northern 'non-paradigmatic') refugia. The phylogeographical analysis is intimately connected with the expansion and retreat of populations. These theoretical considerations should be tested in connection with recent results of historical and recent climatic changes.
Hungary