Climate change may represent one of the greatest threats to biodiversity in human history, however understanding how populations will respond to climate change remains a major challenge. In order to identify relationships between abundance and climate, long term data sets are needed. On Barro Colorado Island (BCI) long term monitoring programs have been established and maintained by STRI since 1972 (http://stri.si.edu/sites/esp/). In addition to collecting data on temperature and rainfall the program monitors several terrestrial taxa, including populations of A. apletophallus. These data are invaluable to the wider scientific community and provide a great opportunity to investigate how climate change and population abundance are related. In collaboration with Robin Andrews we are investigating how A. apletophallus population abundance has changed over time and if changes in abundance are related to climate change.
The climate on BCI has changed in the last 40 years, in particular there has been a pronounced increase in minimum (night-time) temperature. Although total rainfall was unchanged over the study period, rainfall intensity has increased and rainfall now falls on fewer days. Analysis of the lizard census data revealed a decline in lizard abundance on BCI since 1971 and a relationship between population growth rate and the previous years’ southern oscillation index: population growth rate was higher in cooler la niña years. We also found that annual recruitment was negatively related to increasing minimum temperature and increasing rainfall.
Stapley, J. Garcia, M. an Andrews, R.M. (2015) Long-term data reveal a population decline of the tropical lizard Anolis apletophallus, and a negative affect of el nino years on population growth rate. PLOS ONE
My blog post on Anole Annals about the research.