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Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)

January 1, 2011

We studied adult survival and population growth at multiple maternity colonies of big brown bats (Eptesicus fuscus) in Fort Collins, Colorado. We investigated hypotheses about survival using information-theoretic methods and mark–recapture analyses based on passive detection of adult females tagged with passive integrated transponders. We constructed a 3-stage life-history matrix model to estimate population growth rate (λ) and assessed the relative importance of adult survival and other life-history parameters to population growth through elasticity and sensitivity analysis. Annual adult survival at 5 maternity colonies monitored from 2001 to 2005 was estimated at 0.79 (95% confidence interval [95% CI] = 0.77–0.82). Adult survival varied by year and roost, with low survival during an extreme drought year, a finding with negative implications for bat populations because of the likelihood of increasing drought in western North America due to global climate change. Adult survival during winter was higher than in summer, and mean life expectancies calculated from survival estimates were lower than maximum longevity records. We modeled adult survival with recruitment parameter estimates from the same population. The study population was growing (λ = 1.096; 95% CI = 1.057–1.135). Adult survival was the most important demographic parameter for population growth. Growth clearly had the highest elasticity to adult survival, followed by juvenile survival and adult fecundity (approximately equivalent in rank). Elasticity was lowest for fecundity of yearlings. The relative importances of the various life-history parameters for population growth rate are similar to those of large mammals.

Citation Information

Publication Year 2011
Title Adult survival and population growth rate in Colorado big brown bats (Eptesicus fuscus)
DOI 10.1644/10-MAMM-A-162.1
Authors Thomas J. O'Shea, Laura E. Ellison, Thomas R. Stanley
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Mammalogy
Series Number
Index ID 70034876
Record Source USGS Publications Warehouse
USGS Organization Fort Collins Science Center