Climate change drives frog call change in Puerto Rico: Predictions and implications

Abstract

Acoustic signal production and reception in ectotherms are acutely temperature-dependent. We recorded the advertisement calls of the Puerto Rican coqui frog (Eleutherodactylus coqui) along an altitudinal gradient and repeated the measurements twenty-three years later. We found that over this period, at any given elevation, calls exhibited both significant shortening of their duration and increases in pitch. We also found that the observed differences are consistent with a movement to higher elevations for the population, a familiar response to rising ambient temperature. Using temperature data obtained from four local weather stations over the same time period, we confirmed a significant ambient temperature increase, the magnitude of which closely predicts the observed changes in the frogs’ calls. Physiological responses to long-term temperature rises include reduction in individual body size and thus, population biomass. These changes can have alarming consequences, since coqui frogs form an essential component of the food web in the Puerto Rican rainforest. (Work supported by UCLA Academic Senate via Grant No. 3501.)