Assessment of key reproductive traits in the Apennine brown bear population

Abstract

Abstract Although knowledge of reproductive parameters is critical to project the probability of persistence of small and endangered populations, no such data are available for the relict Apennine brown bear (Ursus arctos marsicanus) population (central Italy). From 2005 through 2014, we compiled re-sight data on marked adult female bears (3 ≤ n ≤ 10/yr, for 78 total bear-years) and unmarked, distinct family groups (n = 17) to estimate basic reproductive traits in Apennine bears. We had a high rate of radiocollar failure, so we included in our sample marked, adult female bears with non-functioning radiocollars and used multi-event models in a capture–recapture, robust-design framework to correct for their incomplete detection and potential classification error. We obtained annual detection probabilities of 0.77 and 0.82 for reproductive and non-reproductive female bears, respectively, and the classification error of their reproductive state was negligible (P = 0.003). Mean litter size was 1.9 (±0.7 SD) cu...