Estimating Population Size of Grizzly Bears Using Hair Capture, DNA Profiling, and Mark-Recapture Analysis

Abstract

We used DNA analysis to estimate grizzly bear (Ursus arctos) population size in a 9.866-km 2 area in southeast British Columbia and a 5,030-km 2 area in southwest Alberta. We sampled bears by removing hair at bait sites surrounded by a single strand of barbed wire. DNA profiling with microsatellites of the root portion of the hair was used to identify individuals. We collected hair from 109 different bears and had 25 recaptures in 5 10-day trapping sessions in British Columbia. In Alberta we collected hair from 37 bears and had 9 recaptures in 4 14-day sessions. A model in program CAPTURE (M h ) that acconmodates heterogeneity in (individual capture probaluilities estimated the population size in British Columbia as 262 (95% CI = 224-313) and in Alberta as 71 (60 100), We believe that hair capture combined with DNA profiling is a promising technique for estimating distribution and abundance of bears and potentially many other species. This approach is of special interest to management biologists because it can be applied at the scale conservation and management decisions are made.