engleski

Application of genetic tools in brown bear management in Croatia

Brown bears in Croatia are a game species and through the hunting management since the 1950s the population grew from less than 100 bears to the current estimate of 600 to 1000. According to the management plan, hunting of bears is dane through yearly quotas. However, presently, the decision of quota size is made with out the necessary knowledge on the scientifically based population estimate and it's genetic status. This is the source of various complains: same believe that the quota should be much higher, believing that there are too many bears, and the others are against any quota fearing the population can not sustain such losses. As the bear range is also inhabited by humans, typically the capacity of the habitat is above the social capacity, i.e. above the point when the conflict (damages and threats to human safety) is perceived as unacceptably high. Hence, knowledge about the actual population size of the brown bear population is a prerequisite for the gaining and maintaining of pu blic acceptance of the bear in Croatia. To investigate the genetic diversity of Croatian brown bear population, we surveyed 13 polymorphic microsatellite loci for 90 bears and obtained partial mitochondrial DNA control region. sequences (267 bp) for 71 bears that had been hunted or accidentally killed during 2005/06 and whose muscle tissue samples we had received. The mean allelic diversity per microsatellite locus was 6.54, ranging from three to 10 alleles, which is relatively high. The analysis of mtDNA control region sequences revealed only two haplotypes that differ by two nucleotides, and whose frequencies were 0.18 and 0.82. This extremely law mtDNA haplotype and nucleotide diversity may indicate pop.ulation bottleneck in the recent past by severe hunting and should be explored further. Genotyping of bear scat samples using six microsatellite loci for individual identification is now in progress with DNA extracted from over 500 samples. The procedure will be followed with statistical elaboration and population viability modeling. With more sam ples coming in and further analysis, genetic data shali provide scientific guidelines for brown bear management in the future. Traditionally bear managers counted the animals at feeding sites. That method suffered of biases but the genetic method and standardization of hunter's counts will allow the calibration of traditional methods and the continuous insight in the population trend. On the internationallevel the results of this study will help conserve the brown bear on the European level, and will help Croatia to comply with conventions signed (Bern, Habitat directive, CITES).

bear; genetic diversity; microsatellite; mitochondrial DNA control region

nije evidentirano