Biological impacts of climate warming are well documented at mid- to high latitudes, where warming is relatively rapid. However, recent theoretical models predict that tropical coldblooded species (called ectotherms), such as plants, insects, reptiles, fish, are also vulnerable to warming, even though tropical warming is relatively slow. An immediate way to test whether tropical ectotherms are being affected involves comparing current physiological and ecological data with historical data gathered prior to recent warming. Thus, by replicating historical studies, physiological and ecological changes that may have already occurred in parallel with recent climate warming can be detected. Puerto Rico is the ideal venue for such comparisons. In the 1970s and 1980s (prior to recent warming), extensive baseline studies were made of the physiology, reproduction, and ecology of Anolis lizards. No comparable data sets exist for any tropical ectotherm. Puerto Rico has warmed since those baseline studies and is projected to warm more. Simulations predict that these warmer temperatures should have induced heat stress in forest Anolis populations in the summer, but actually increased reproduction during the winter. To test these predictions, baseline study sites will be revisited, and reproductive rates, body and environmental temperatures, and feeding success will be quantified and compared to parallel data collected 25-30 years ago. The investigators who did the original studies will replicate their own studies: thus comparisons between decades will not be influenced by between-investigator differences.
Broader impacts of the Research: If these studies document that tropical ectotherms are indeed vulnerable to climate warming, the ecological, agricultural, and economic implications are serious because the tropics are the earth's center of biodiversity and its main engine of primary productivity. In many tropical habitats, reptiles and amphibians are key component of the food web and their loss may precipitate catastrophic changes in tropical communities. The project will provide training in field ecology and physiology to undergraduate and graduate students from five universities or colleges. Under-represented minorities will be recruited from the University of Puerto Rico (undergraduates, graduates) and from LaGuardia Community College (NYC), both of which enroll largely minority undergraduate populations. Undergraduate women will be recruited from Barnard College, a women's college. Outreach to pre-college teachers and students will be an important component of the project and will take place through established connections with organizations such as the New York State STEM Initiative, the Ohio State STEM Learning Network, and the American Museum of Natural History. A public symposium at the University of Puerto Rico will enable project researchers, Puerto Rican scientists, and students to interact and share research ideas and results. A new generation of field workers will be mentored: they can potentially replicate these studies in future decades and thus maintain this unique time series of physiological and ecological responses of tropical ectotherms to climate warming.
