Run to the Caves: Frog Refuges From Harsh Environments

ABSTRACT

The use of caves by primarily nontroglobiont organisms can be critical when the conditions of surrounding epigean habitats deteriorate as a result of synergic effects of climate changes and degradation of native vegetation cover. Under scenarios of unbalanced temperatures, high solar incidence, low humidity and reduced shelter availability in the external landscapes, caves may become attractive refuges, particularly for desiccation‐sensitive animals such as the amphibians. We investigated the role of 96 iron caves in the southeastern Amazon as shelters for frogs, testing the hypotheses that species abundance in caves is higher during the dry season than the rainy season; species abundance during the dry season depends on interactions between resource availability within caves and natural and anthropogenic landscape features; and the relative dominance of turnover versus nestedness components of the beta‐diversity shifts seasonally in response to climatic variation. We documented five frog species using caves, two of which were more abundant during the dry season. Overall, generalized linear models provided evidence supporting our hypotheses and revealed that cave use is highly species‐specific. Therefore, the biology of species should be considered to understand the structure of frog assemblages within caves. Our findings also indicate that frogs act as trogloxenes, using caves opportunistically when they are available and when epigean habitats become unfavorable rather than exclusively relying on caves for completing their life cycles.