Freshwater systems provide a fascinating interface with the terrestrial world: streams, rivers, and lakes have extensive edges and strong relationships with surrounding vegetation. How is species richness and in the aquatic habitat related to land cover type on the streambanks? How do inputs from terrestrial systems move through the aquatic foodweb? I am also interested in exploring how ecosystem functioning in streams is affected by the community composition of both the aquatic and terrestrial ecosystems surrounding them.
|Meta-Ecosystems Dynamics in Streams
The meta-ecosystems concept scales up the idea of meta-communities by adding the transport of material and energy – so instead of only dispersal of organisms between patches, the patches are separate ecosystems with their own dynamics. This is a relatively new topic for empirical and experimental study. Stream systems are an ideal venue to study the meta-ecosystems concept because organisms disperse up and down the stream corridor, and material from the terrestrial system moves into and through the stream as well. I plan to use both field and laboratory approaches to address this topic, and am also interested to see how results from the two different strategies match up.
|Environmental Conditions and Species Distributions
One of the central questions in ecology is, why are species found where they are? This becomes an even more interesting topic given the inevitability of changing climate conditions. Using alpine plants, I ask how not only temperature but other observed variation in environmental conditions affects performance. Many factors which may be important for species persistence, like community interactions and resource availability, are neglected in climate models which predict how distributions will change in the future. I’m also interested in the scale at which we study these questions, and how scale might change the answers we find.
|Global Change Impacts on Plant Communities
One of our best options for understanding what effect future climate change might have on natural ecosystems comes from long term manipulations. Working with field sites which have been undergoing warming for one to two decades as part of the International Tundra Experiment (ITEX), I examine community composition and ecosystem functioning. Are responses to simulated global change consistent across regions, community types, and functional groups, or does heterogeneity of these responses make it difficult to predict the sum of global change effects? More than simply examining how species distributions and community character might change, I’m interested in what effect this might have on the ecosystems themselves.