Macroecology of reproductive modes in the diverse anuran fauna of the Brazilian Atlantic Forest

Abstract

Anurans exhibit the widest variety of reproductive modes among tetrapod vertebrates. The Atlantic Forest is a hotspot for biological conservation; however, biogeographic documentation of the richness of anuran reproductive modes are underexplored. By overlaying maps of 249 species having reproductive modes with aquatic eggs and 101 species with non-aquatic eggs, we described the geographical patterns of anuran reproductive modes in the Atlantic Forest and identified the main correlates of reproductive diversity of these two major types of anuran reproduction. We found the greatest diversity of reproductive modes in the coastal region of the Atlantic Forest, whereas a smaller number of reproductive modes was found in inland regions of the hotspot. These regions are broadly characterized by deciduous/semideciduous forests and a warmer and more seasonal climate regime in southeastern and southern Brazil. In this climatically harsher region, reproductive modes were more basal and generalized in anurans. Correlative analyses showed that the richness of reproductive modes with aquatic eggs can be described by general combinations of climate, topography, and vegetation types, whereas larger numbers of reproductive modes with non-aquatic eggs are better described by specific variables of temperature seasonality, amount of ombrophilous forests, and rugged topography. The predictors identified here are environmental variables that should be continuously monitored in situ; identifying threshold values that could lead a species to a critical conservation status is key to efficiently protecting the rich anuran fauna of the Atlantic Forest.