Determining how climate change affects global ecology and ecosystem services is one of the most important frontiers in environmental science. In 2011 I reviewed the evidence for the effects of climate change on size across a wide array of organisms (Sheridan & Bickford 2011). This review garnered global popular media attention, and was covered by the Associated Press, Reuters, The New York Times, and New Scientist. Our review pointed out that ectotherms are likely to be strongly affected due to the direct relationship between temperature and metabolism. To test this prediction, I led a study examining spatially-explicit changes in North American wood frog (Lithobates sylvatica) body size and phenology over the last century across nearly thirty degrees of latitude. We found that while climate, size, and phenology are all changing across large geographic scales, changes in phenology are predicted by climate change at spatially-explicit scales, but body size changes are not. This indicates that, contrary to our earlier hypothesis, climate itself may not be the mechanism responsible for observed size changes.
However, temperate species experience simultaneous increases in growing season length, so to isolate the impacts of temperature and precipitation, I examined changes in tropical frog sizes using museum specimens spanning more than 100 years. This study (in prep) demonstrates that Borneo frogs are indeed getting smaller, that precipitation interacts with temperature, and that females respond more strongly than males. This work is notable because size changes of tropical ectotherms are poorly studied, but will have some of the largest impacts on predictions of ecosystem responses to climate change. Additionally, we reviewed updated evidence on this topic and found that the majority of studies examine birds, mostly from North America, and there may be sex differences in climate response across taxa, highlighting important directions for future work.
Next steps will include examination of tropical reptiles which are the least studied vertebrate group, and comparison of size changes in fragmented vs. unfragmented habitats, to better predict how the combined effects of climate change and fragmentation impact physiology.
However, temperate species experience simultaneous increases in growing season length, so to isolate the impacts of temperature and precipitation, I examined changes in tropical frog sizes using museum specimens spanning more than 100 years. This study (in prep) demonstrates that Borneo frogs are indeed getting smaller, that precipitation interacts with temperature, and that females respond more strongly than males. This work is notable because size changes of tropical ectotherms are poorly studied, but will have some of the largest impacts on predictions of ecosystem responses to climate change. Additionally, we reviewed updated evidence on this topic and found that the majority of studies examine birds, mostly from North America, and there may be sex differences in climate response across taxa, highlighting important directions for future work.
Next steps will include examination of tropical reptiles which are the least studied vertebrate group, and comparison of size changes in fragmented vs. unfragmented habitats, to better predict how the combined effects of climate change and fragmentation impact physiology.