I am very interested in how climate changes – both natural and anthropogenic – affect the distributions of species and composition of communities.
Understanding the impacts of expected climate change on plant communities over the next 100-200 years is a crucial and very difficult challenge for ecologists. I have pursued several alternative approaches to predicting climate change impacts, including trait-based predictions and metaanalyses of experimental and observational studies. A central theme of these is trying to move past simple projections based on species ranges and distribution model projections to incorporate more of what we know about plant physiology, succession and community dynamics. Jens-Christian Svenning and I discussed these issues in a review examining the likely importance of disequilibrium vegetation responses to climate change in the next 50-200 years (Svenning and Sandel 2013, American Journal of Botany).
I am also interested in the effects of past climate changes on species distributions. Improved modeling and data on paleoclimate allow us to make detailed studies about climate change and stability during the late Quaternary. Climate stability appears to have important impacts on species distributions, range size, diversity and community structure for a wide variety of organisms. A measure of climate stability, climate-change velocity, measures the rate at which species must migrate to track a given climate condition. My first project looking at the measure related it to global endemism patterns of amphibians, mammals and birds. Recent work (much of it led by Bo Dalsgaard and Matthias Schleuning) has developed towards trying to understand the influence of climate-change velocity on the structure of species interaction networks, including specialization and modularity. I am working towards understanding more subtle effects of climate changes on community structure and function, particularly in forests, under the STABFOR project.