Opportunistic habitat use: widespread and non-threatened anurans in Brazilian caves

Anurans are highly sensitive vertebrates whose ecological distribution is strongly shaped by environmental conditions, particularly moisture availability and habitat stability. Although most species are associated with epigean environments, several anurans use subterranean habitats, such as caves, as shelters, refuges, or complementary habitats. Caves represent unique ecological environments in Neotropical landscapes and are characterized by high environmental stability, acting as ecological filters that select for species capable of utilizing them. Because anurans typically depend on humid environments and are predominantly nocturnal, they are potential users of subterranean environments. In this study, we evaluated how taxonomic variables (species and family) relate to the conservation status, geographic distribution, and life-history traits of anurans recorded in natural caves in Brazil. For this purpose, 177 occurrence records for 54 species were compiled from the scientific literature. The species were characterized by their conservation status, distribution range, endemism, and life-history attributes (period of activity, habitat frequency, and mating site). The data were analyzed using redundancy analysis (RDA). The results indicate that geographic and conservation-related variables (conservation status, distribution range, and endemism) are the main predictors of anuran occurrence in caves. The predominance of widely distributed anurans classified as IUCN Least Concern suggests that their use of caves is opportunistic, with caves functioning primarily as refuges or as complements to surface habitats. These findings indicate that cave use by anurans is largely driven by ecological plasticity rather than specialization to subterranean environments, and, by compiling and analyzing records from across Brazil, this study provides the first macroecological synthesis of cave-associated anurans in the country, highlighting important sampling gaps and reinforcing the need to systematically incorporate amphibians into research and conservation policies for Neotropical subterranean ecosystems.