The Role of Invasive Earthworms as Ecosystem Engineers and the Associated Implications for Tree-Ring Research in the Great Lakes Region of North America

Category: Time:
Wednesday, February 20, 2013 - 12:00 to 13:00
Access:
public
Room: Speaker:
Evan Larson
Affiliation:
University of Wisconsin, Platteville
Contact:
Matt Salzer
Calendar Status:
confirmed

European earthworms have only recently been recognized as an invasive threat to the hardwood forests of the Great Lakes Region of North America, yet mounting evidence indicates that the invasion of earthworms into forests that had been earthworm-free since at least the last glacial maximum is profoundly and fundamentally altering nutrient cycling, soil structure, and the forest floor communities of these ecosystems. Less attention has been given to how earthworm invasions influence tree growth and productivity. We examined patterns of tree growth and basal area increment at four recently invaded sites in northern Minnesota and Wisconsin and identified at times subtle and at others dramatic differences in growth that appear to be the direct results of environment changes wrought by earthworms. In some cases, earthworms altered the growing environment sufficiently to drive changes in how trees responded to climate variability. These results raise important and potentially profound questions for dendroclimatological research throughout the Great Lakes Region.