Pairing Noninvasive Surveys with Capture-Recapture Analysis to Estimate Demographic Parameters for Dendrobates auratus (Anura: Dendrobatidae) from an Altered Habitat in Costa Rica

Abstract

Amphibian populations are in decline worldwide. Monitoring programas are important, but many studies use invasive techniques to handle, mark, and identify individuals. We recommend a noninvasive technique in which individuals can be identified from photographs basedon individual markings for capture-recapture analyses. As a case study, we examined the population dynamics of dendrobates auratus at a highly altered habitat in northern Costa Rica. We applied the robust design to the capture-recapture data from the photographs of individual frogs at two 25-m transects, a parking lot and a gravel walkway. From these data, we estimated parameters for survival, emigration, immigration,abundande, and capture probability. The observed mean density estimate of 2.62+-0.60 individuals (CI=1-4) per 100 m2 is the first statistically rigorous estimate for this species in altered habitats. These results suggest that this species might be suited to occur in human-altered habitats and may be less susceptible to population declines than previously suggested.Our noninvasive methodology to obtain robust abundance and demographic parameter estimates is also applicable to citizen-science surveys for a variety of taxa of amphibians and reptiles that are individually identifiable.

Keywords

• Amphibian populations
• Capture-recapture
• Noninvasive surveys
• Photographic identification
• Robust design