October 20 2009

12:00 154 BSRB

Ecolunch: Peter Narins
Physiological Science & Ecology & Evolutionary Biology

Long-term effects of climate change on frog calls.


In this work-in-progress I will discuss a project in which the calls of male treefrogs (Eleutherodactylus coqui) were studied along an altitudinal gradient in the Luquillo Mountains in eastern Puerto Rico in 1986. The fundamental frequency of each note was highly negatively correlated with altitude, whereas the call duration and snout-vent length (SVL) were highly positively correlated with altitude. These measurements were then repeated after a 20-year period had elapsed. Although the data exhibited the same general trends over this 20-year period, the temperature had risen significantly at the middle elevations, whereas there was no such change in the sea level temperature. Using the bootstrap method, we generated distributions of the regression line slopes through the 2006 data and then combined these with the distributions of the regression line slopes through the 1986 data (Chow Method). Distribution shifts indicate an effect and we argue these are likely due to long-term temperature changes. Those of you with statistical expertise can plan on making significant contributions to the discussion!











































































































































































































































































































































































































































































































































































































this is idtest: