Density and population size estimates for North Cascade grizzly bears using DNA hair-sampling techniques

摘要: Abstract We used non-invasive DNA hair-sampling and catch per unit effort (CPUE: grizzly bears detected 1000 trap nights) to estimate relative density population size for a threatened bear in the North Cascade Ecosystem of Washington British Columbia. linear, logistic, linear through origin regression analyses relationship between seven other populations. One was during 5304 nights (CPUE=0.19) over 3 years Cascades. This CPUE much lower than populations, including two populations Cabinet-Yaak Selkirk Mountain Ecosystems. The logistic model (curvilinear relationship) best fit data (R2=0.927), yielded estimates 0.15 bears/100 km2 (90% CI=0.03–0.71) six CI=1–27), respectively. Natural recovery seems unlikely because has high likelihood extinction due demographic environmental stochastic effects associated with extremely small numbers. recommend augmentation. models can be useful method evaluate densities numbers animals small, when sample sizes are too yield traditional mark–recapture analysis.