Abstract
Direct observations have been conducted in the past to estimate the population size of the Asiatic black bear (Ursus thibetanus) in Iwate prefecture. To improve the precision of the population estimate, we applied a DNA-based method using hair-trapping since 2004. Through the experiences of these research projects, several problems have been identified concerning hair-trapping. First, there are structural problems to the trap. When we used a single strand of barbed wire, the hair collection rate was about 80 percent. By using two barbed wires each trap, we were able to collect hair samples in all traps. Secondly, the genotyping success rate of hair samples collected after August tended to decrease compared with those collected in June and July. DNA degradation was likely caused by the high temperature and humidity of summer. Another problem is that the placement of the trap was limited. Terrain irregularities and steep slopes disturbed, and sometimes prevented, the placement of traps. Therefore, it is necessary to develop a new trap not controlled by terrain conditions. By overcoming these problems one by one, we would continue to make progress on DNA-based population estimates using hair-traps.
