Abiotic correlates of anuran calling phenology: the importance of rain, temperature, and season
We surveyed anuran calls nightly at eight ponds in eastern Texas from 1 January 2001 through 31 December 2002. Air temperatures and daily rainfall also were recorded for each of the sites. Eastern Texas contains a diverse temperate anuran fauna and a climate that provides a range of conditions for anuran reproduction. During our study, we measured air temperatures that fluctuated seasonally with extremes from 0 to 29 C at 2100 h. We found rainfall to be generally abundant with occasional flooding events, however, prolonged periods of no precipitation were also observed. Given the level of anuran diversity and the amount of seasonal variation in temperature and rainfall in our temperate climate we expected to find a variety of breeding strategies. Results from our analyses did indeed suggest five basic breeding strategies based on anuran calling: (1) breeding within a predictable season (summer) independent of local weather patterns; (2) breeding opportunistically within a predictable season (summer) dependent on local rainfall; (3) breeding opportunistically within a predictable season (winter) dependent on local temperature; (4) breeding opportunistically dependent on local flood level rainfall events; (5) breeding opportunistically year round dependent on local temperature in the winter and local rainfall in the summer.