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Abstract.
The current range and distribution of the common hamster, Cricetus cricetus in Poland was established. The range of the species has dwindled substantially in the course of just 30 years and the process is still going on. The Polish populations are isolated from the Belarussian, Czech and German ones, there is low probability of some exchange with Ukrainian hamsters. Moreover, two main areas of hamster distribution in Poland are isolated from each other. In view of the marked shrinkage and fragmentation of the range, we propose changing the status of this species in Poland from unknown (DD) to endangered (EN).
Key words: distribution, endangered species, range fragmentation, isolated populations
Introduction
As a result of human impact, an ever-growing number of species are listed as extinct, threatened with extinction, or just endangered. In some cases there are species belonging to groups that are commonly assumed to be abundant and considered pests. One of such groups is rodents because of the damage caused by some species to agricultural crops and the transmission of zoonoses. However, in spite of the real evolutionary success of this order of mammals and the real abundance of some species, rodent species are presently regularly being listed as endangered.
The rodent fauna of Europe is represented by 68 species in 10 families (Pucek 1989). The list of the most endangered species in at least one European country contains 28 species, i.e. it comprises 41% of all rodents living in Europe. Ten species considered most endangered at the scale of the continent were selected from this group; among them is the common (European) hamster Cricetus cricetus (Linnaeus, 1758), (Pucek 1989).
The common hamster is a mammal characteristic of an open, steppe-like and cultivated landscape. The Eurasian range of this species is wide and extends from the Yenisey river and the Altai Mountains in the east, through Siberia, eastern and central Europe, to some isolated populations in western Europe (Niethammer 1982, Berdyugin & Bolshakov 1998). In the past, the species thrived thanks to the expansion of agriculture, was encountered commonly, and very abundant. In some parts of the range it was characterised by mass outbreaks in not very regular, 5-7 years' cycles (N e c h a y et al. 1977). Because...