Survival and Abundance in Males of the Glass FrogEspadarana(Centrolene)prosobleponin Central Panama

Abstract

While many amphibian species around the world are experiencing catastrophic declines, we have little understanding of the population dynamics of the majority of species. Estimating demographic parameters can help us understand the spatial and temporal dynamics of healthy populations, assess how populations may be impacted by threats, and interpret the recovery of diminished populations. Capture–mark–recapture (CMR) techniques represent a powerful approach for estimating such vital rates, but they have been used rarely in studies of tropical amphibians. We use 5 yr of mark–recapture data (2000–2004) to estimate survival probabilities and abundances of the stream-breeding frog species Espadarana (Centrolene) prosoblepon prior to the arrival of Batrachochytrium dendrobatidis, the amphibian chytrid fungus. We estimated these parameters for male E. prosoblepon on four streams (Cascada, Guabal, Loop, and Silenciosa) in Parque Nacional Omar Torríjos in central Panama. Across all streams and years, mean annual survival probability was 0.46 (0.41–0.52, 95% CI). Abundance varied among streams, with larger population sizes on Loop (78 ± 12 SE) and Cascada (64 ± 4) and smaller population sizes on Guabal (28 ± 3) and Silenciosa (30 ± 2), but showed little difference among years. Streams with different abundances had similar survival rates, and we suggest that availability of overhanging vegetation—used for oviposition and male territories—limits population size. These are the first survival and abundance estimates that exist for this species. They provide a critical baseline for comparison to other healthy populations and for evaluating recovery in sites infected with the amphibian chytrid fungus.