European earthworms that have colonized northern forests can profoundly alter the dynamics of carbon (C) and nitrogen (N) in the ecosystem. Fahey labeled leaf litter and fine roots of sugar maple forests with heavy isotopes of C and N. He then traced these elements through the soil food web in earthworm-invaded and earthworm-free sites.
By mixing together litter and soil, and its passage through their gut, earthworms modify the soil microbial community and its activity. As a result, lots of C is lost from the soil and the cycling of nitrogen is perturbed. Most surprising, earthworms apparently consume lots of the fine roots and mycorrhizae of the trees. The possible implications of earthworm invasions for forest health will be explored.
Timothy Fahey is a Professor in the Department of Natural Resources at Cornell University. A forest ecologist, he is active in field teaching and research with both graduates and undergraduates. At Cornell he has been recognized as Liberty Hyde Bailey Professor and Stephen H. Weiss Presidential Fellow, and has received the Chancellor's Award for Teaching.
This seminar is free and open to the public.