Freshwater systems provide a fascinating interface with the terrestrial world, because a large part of the material and nutrients of the food web come from terrestrial detritus. How is biodiversity in aquatic habitats related to land cover and terrestrial subsidies? How do inputs from terrestrial systems move through the aquatic foodweb? In my PhD work, I am also studying how ecosystem functioning in streams is affected by the community composition of both the aquatic and terrestrial ecosystems surrounding them.
The meta-ecosystems concept scales up the idea of meta-communities by adding the transport of material and energy. Instead of considering only dispersal of organisms as a link between patches, this framework considers patches as ecosystems with their own dynamics, linked by movement of both living and dead or abiotic materials. This is a relatively new topic for empirical and experimental study. With my Eawag colleagues (Florian Altermatt, Emanuel Fronhofer, Isabelle Gounand, and Eric Harvey) we have been exploring this area using experiments, fieldwork, and synthesis, and have identified several exciting new study directions.
|Environmental Conditions, Community Assembly, 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. In my masters, I used alpine plants to ask how not only temperature but other observed variation in environmental conditions affects performance. In my PhD, I looked in aquatic systems to see the influence of environmental conditions but also other metacommunity processes like dispersal limitation, as well as local competition, on macroinvertebrate communities. I’m most interested in looking at how different scales interact in delineating species distributions.
|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.