Abstract
It is urgent to establish practicable methods for estimating bear population size for the management and conservation of two species of bear (Ursus arctos and U. thibetanus) in Japan. Noninvasive sampling techniques and DNA-based capture-mark-recapture methods have drawn attention as population estimate measures because these methods can be more efficient and less biased than the traditional capture-mark-recapture methods with live-trapping. These methods have become increasingly common and have proven to be powerful means for estimating bear population size in many countries. However, in Japan, the methods have not been adopted effectively due to some open problems. To consider the effective application of these methods, we scrutinized previous studies conducted in Japan and other countries and reviewed problems in three processes: sampling, genotyping, and population estimation. We suggest that well-designed planning by the ecologist, geneticist and mathematical modeling specialist is most vital to the success of DNA-based capture-mark-recapture methods. We also suggest that DNA-based capture-mark-recapture methods would work more effectively if applied to large scale projects targeting the whole range of a local bear population.
