Relative influence of weather and season on anuran calling activity

Drivers of anuran reproductive activity may include multiple and independent environmental variables. To determine the relative influence of season, temperature, and precipitation in initiating frog reproduction, we monitored a species-rich frog assemblage in south-central Alabama for 3 years and modeled calling activity of vocalizing males, who call to attract mates. We evaluated multiple hypotheses potentially explaining calling activity and we were able to identify significant influences of calling activity for all 11 anuran species considered in the analysis. Eight species were significantly influenced by month of survey and four of these were influenced by at least one additional environmental variable. In our study, precipitation was relatively unimportant in influencing calling activity, likely because breeding pools at the site are semipermanent and the species we sampled are not generally reliant on ephemeral wetlands. In general, our data suggest that different species within the same wetlands respond to different cues when initiating reproduction and calling activity is largely based on a combination of both environmental conditions and either seasonal changes or endogenous drivers.