BAT COMMUNITIES OF 3 SMALL PSEUDOKARSTIC CAVES IN EASTERN BOHEMIA (CZECH-REPUBLIC)

Bat communities of three small pseudokarstic caves in the Svitavska pahorkatina Highland (Eastern Bohemia, Czech Republic) were investigated by nettings and winter censuses between 1985 to 1992. A total of 821 records of 11 netted species and 1 672 records of 7 over-wintering species were evaluated. M. emarginatus, P. auritus and M. nattereri dominated in the samples obtained by netting (32, 23, and 19 %, respectively). The dominance of M. emarginatus in the sites studied seems to be the highest found in central Europe. R. hipposideros prevailed in wintering bat assemblages (94 %), and one of the caves studied appeared to be the most densily occupied hibernaculum of this species in Bohemia. The species diversity index was 2.56 in the total sample obtained by netting and 0.38 in the assemblage of wintering bats. A netted specimen of M. blythi represented the record of extreme NW edge of the species' central-European range. The area studied represents a part of a corridor used for dispersal of certain bat species from southern Moravian lowlands to the Bohemian basin, the reason termophilous species of south-European origin were found with local species of European forest origin. Considerable heterogeneity in bat community composition was observed, formed in the period of transitory migrations and/or in winter within a small and geographically closed territory and underground shelters of a similar type. The results of both methods applied were not correlated, and the attractiveness of caves to bats differed in the period of transitory migrations and in winter.