Spatial capture-recapture reveals age- and sex-specific survival and movement in stream amphibians

Oecologia
By: , and 

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Abstract

Life history information sets the foundation for our understanding of ecology and conservation requirements. For many species, this information is lacking even for basic demographic rates such as survival and movement. When survival and movement estimates are available, they are often derived from mixed demographic groups and do not consider differences among life stages or sexes, which is critical because life stages and sexes often contribute differentially to population dynamics. We used hierarchical models informed with spatial capture-mark-recapture data of Ascaphus montanus (Rocky Mountain tailed frog) in 5 streams and A. truei (coastal tailed frog) in 1 stream to estimate variation in survival and movement by sex and age, represented by size. By incorporating survival and movement into a single model, we were able to estimate both parameters with limited bias. Annual survival was similar between sexes of A. montanus (females = 0.885 [95% CI: 0.614–1], males = 0.901 [0.657–1]), but was slightly higher for female A. truei (0.836 [0.560–0.993]) than for males (0.664 [0.354–0.962]). Survival of A. montanus peaked at mid-age, suggesting that lower survival of young and actuarial senescence may influence population demographics. Our models suggest that younger A. montanus moved farther than older individuals, and that females moved farther than males in both species. Our results provide uncommon insight into age- and sex-specific rates of survival and movement that are crucial elements of life-history strategies and are important for modeling population growth and prescribing conservation actions.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Spatial capture-recapture reveals age- and sex-specific survival and movement in stream amphibians
Series title Oecologia
DOI 10.1007/s00442-019-04464-3
Volume 190
Issue 4
Year Published 2019
Language English
Publisher Springer
Contributing office(s) Fort Collins Science Center, Northern Rocky Mountain Science Center
Description 13 p.
First page 821
Last page 833