Author

Lauren Alteio

Date of Award

5-2014

Document Type

Thesis

Department

Environmental and Forest Biology

Thesis Advisor

Thomas R. Horton

Abstract

Native earthworms are believed to have been removed from the northeastern United States during the last period of glaciation, and have since been slow to recolonize. In areas that have been colonized, non-native earthworms have caused major impacts to the litter layer and soil horizons, rapidly consuming litter and homogenizing soil horizons through burrowing activity. In this study, we used colorimetric enzyme assays to observe the potential earthworm impacts on soil microbial decomposition. We hypothesized that earthworms would increase the production of oxidative enzymes, which degrade recalcitrant litter, due to preferential consumption of labile leaf litter. Through this study, we found that earthworms have impacts on the production of oxidative enzymes in the organic horizon, promoting increased phenol oxidase activity in order to decompose more recalcitrant nutrient sources. The long-term effects of non-native earthworms should be further studied, and may impact forest conservation and management programs in the future.

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