Noninvasive genetic studies of brown bears using power poles

One difficulty in the conservation of endangered wildlife is the lack of reliable information on its status. This lack of knowledge can often be attributed to financial and logistic constraints as well as the lack of trained personnel to collect data. We test a simple method to study bears in the southern Balkans by inspecting power poles, which are used by bears for marking and rubbing purposes. We created a network of barbed-wire fitted poles for the collection of hair samples, evenly distributed throughout six study areas. During 87 sampling sessions in the main study area, we collected 191 samples and identified six microsatellite loci that were variable enough for individual bear identification. The most and best-quality hair samples were collected during the mating period, and DNA was most successfully extracted from samples remaining <4 weeks in the field. In the six study areas, we identified 47 bears. An advantage of using power poles for hair sampling is their availability and accessibility; no bait is required, and the network can be easily set up. A drawback may be an unequal capture probability of sex and age classes of bears. Despite this limitation, using power poles proved to be a simple and cheap method for the noninvasive genetic study of bears that did not require any prior knowledge on habitat use and activity patterns. The method is suitable for large-scale surveys to estimate distribution and relative densities of bears and could also be applied for studying other species.