Testing the influence of habituation on genetic structure of brown bear (Ursus arctos)

Abstract

Adult bear individuals live solitary and haveprolonged parent-offspring relationships, therefore the share of learned skills compared to the inherited ones is much larger than in other carnivores. This promotes acquisition of deviated behavior and simultaneously establishment of a kinship structure. However, deviated bear behavior and human food conditioning are the symptoms of habituation. The aim of this paper is to test the genetic structuring of habituated and non-habituated individuals located in the central region of Romania (Brasov and Prahova districts), a hotspot in terms of human-bear conflicts. Seven microsatellites were used to genotype 145 samples (ear clips and tissue), out of which 82 were classified as habituated and 63 as wild individuals, respectively. Our results suggest the presence of kinship structures in habituated bear group and a reduction of genetic diversity (He = 0.75), while the group located in the wild registered a higher genetic diversity (He = 0.78) and more private alleles. The genetic differentiation suggested by the Neighbor joining cluster analysis has been strengthened by the two percent (AMOVA) differences between the two groups and highlights the negative impact of brown bear kinship structure, caused by the human expansion on wilderness. The genetic analyses indicated that the two groups share genetic variants due to the dispersal and breeding patterns of male adult bears. The emergence of genetic differences between the two groups can be avoided by preventing bears to become human-food conditioned; over time, kinship structure can pose a threat to genetic diversity.