Microsatellite diversity and structure of Carpathian brown bears (Ursus arctos): consequences of human caused fragmentation

Abstract

The formerly large, continuous brown bear population of the Carpathians has experienced a radical decrease in population size due to human activities which have resulted in splitting the population into the larger Eastern Carpathian and the smaller Western Carpathian subpopulations. In the Western Carpathians, brown bears came close to extinction at the beginning of 1930s, but thanks to both conservation and management efforts the bear population has begun to recover. In contrast, the Eastern Carpathian subpopulation in Romania has never dropped below 800 individuals, potentially preserving the original amount of genetic variation. In this paper we present results of a genetic study of brown bear subpopulations distributed in the Slovak and Romanian sections of the Carpathians using 13 nuclear microsatellites. The documented level of genetic differentiation between the Western and Eastern Carpathian subpopulations reflects the isolation which lasted almost 100 years. Furthermore, the existence of two, different, genetic clusters within the Western Carpathians despite close geographic proximity indicates that humancaused fragmentation and isolation have resulted in significant genetic divergence. Although the subpopulations display an indication of genetic bottleneck, the level of genetic diversity is within the range commonly observed in different brown bear populations. The results presented here point out the significance of human exploitation to the population structure of this large carnivore species. Future management efforts should be aimed at securing and restoring the connectivity of forested habitats, in order to preserve the genetic variation of the Carpathian brown bear subpopulations and to support the gene flow between them.

Genetic differentiation of western capercaillie in the Carpathian Mountains: the importance of post glacial expansions and habitat connectivity

“…Straka et al . () described a similar pattern of genetic differentiation between the Western Carpathian brown bear ( Ursus arctos ) population and the Eastern one. A study on the Carpathian newt ( Lissotriton montandoni ), combining microsatellite data and ecological niche modelling revealed, consistency of genetically distinct units with the isolated last glacial refugia within the Carpathians.…”

Genetic turnovers and northern survival during the last glacial maximum in European brown bears

“…In Denmark, brown bears appear to have become extinct around 4,800-4,400 cal. This is also most likely the reason why the most diverse bear population in Europe today is found in the Carpathian Mountains (Straka, Paule, Ionescu, Štofík, & Adamec, 2012). (Aaris-Sørensen, 2009), and in Ireland, the latest radiocarbon-dated bear has an age of 3,126 cal.…”

North-South Differentiation and a Region of High Diversity in European Wolves (Canis lupus)

“…Isolation and expansion from different glacial refugia [8], [9], [40] and adaptation to local environments and ecological conditions [12], [41] may have influenced the extent and direction of gene flow in European wolves. Human-related factors such as landscape fragmentation and development [8], [42]–[44], high hunting pressure [45]–[47] including poaching [6], [7], may also have influenced patterns of dispersal. Moreover, wars and uprisings over the past 150 years seem to have exerted a strong influence on wolf dynamics in parts of the study area [48], and may thus have influenced gene flow.…”