When and Where to Find the Tiny Creatures: Environmental Predictors of the Abundance of a Miniaturized Frog Species From Northeast Brazil

ABSTRACT Leaf litter is a complex ecosystem that provides microclimatic conditions for a great diversity of organisms, including small vertebrates, such as lizards and anurans. One adaptation that favours the exploitation of this environment by vertebrates is miniaturization, which allows the occupation of ecological niches unavailable to larger‐bodied animals, but also increases these organisms' dependence on the microclimatic conditions of the leaf litter. In miniaturized frogs, sensitivity to changes in ecological factors related to humidity may be particularly critical, since, in addition to having highly permeable skin, they also possess a high surface‐area‐to‐volume ratio. In this study, we evaluated the influence of relative humidity, rainfall, temperature, leaf litter depth and canopy coverage on the abundance and detection probability of calling males of Adelophryne nordestina , a small, direct‐developing miniaturized frog inhabiting the Atlantic Forest leaf litter in northeastern Brazil. We surveyed calling males of A. nordestina over 9 months across four transects, each containing 25 survey points, totalling 100 study sites. We employed a Negative Binomial N‐Mixture Model to estimate the abundance of calling males and assessed the effect of environmental parameters. The estimated mean detection probability was 0.024, and mean abundance among sites was 47.5 individuals. Precipitation, temperature, leaf litter depth and canopy cover significantly influenced the number of calling males in the study area. We suggest that, as a terrestrial, miniaturized and direct‐developing species, changes in environmental parameters affecting microhabitat humidity impact its reproductive activity. Our findings contribute to the ecology of miniaturized species from leaf‐litter communities and the potential impacts of environmental disturbances on this ecosystem.