Chaparro, C., A.C. Rivera-Burgos, M. J. Eaton, A. J. Terando, E. Martinez, and J. A. Collazo. 2024. Post-release Survival of Eleutherodactylus coqui: Advancing Managed Translocations as an Adaptive Tool for Climate-vulnerable Anurans. Herpetologica.
Abstract
Translocating amphibians to alternative, suitable habitat is an adaptation strategy aimed at minimizing the risk of extinction due projected global warming and drying. Projected conditions could undermine their physiological performance, and thus, survival and reproduction. Translocations minimize risks of extinction by increasing spatial redundancy across climate-resilient habitats, particularly for species with low vagility. However, outcomes of amphibian translocation attempts are poorly documented, and their effectiveness remains unclear. We released and tracked 34 radioed Eleutherodactylus coqui to determine initial, post-release survival under two treatments: non-translocated or control group (n = 14) and translocated group (n = 20) to a different location 0.8 km away, but sharing similar habitat and environmental conditions in west-central Puerto Rico in 2021. We defined “initial” as the first 17 d post-release, a period during which we hypothesized translocated individuals would have lower survival rates as they transitioned from known-familiar habitat to novel unfamiliar habitat. There was no evidence in the data to support our hypothesis. Daily survival rates (DSR) were better explained by a model with constant survival and no treatment effect (DSR = 0.999 ± 0.001). The best supported model (DAICc ≤ 2) indicated that daily survival was negatively influenced by in-situ temperature (i.e., where frogs perched when captured), but the effect was weak (95% CIs overlapped 0). After 17 d, all but one of the recaptured frogs gained weight (avg = 0.28 ± 0.13 g), suggesting that transmitter/harness setup did not impede foraging behavior. Average daily movements did not hinder survival even though translocated individuals travelled more often and farther (1.19 ± 0.35) than non-translocated ones (0.15 ± 0.12 m). Findings suggested that managed translocations have the potential to become a useful conservation tool. We outlined challenges that remain before translocations of Eleutherodactylus species can be broadly applied.