Impacts of invasive earthworms on carbon storage in southern boreal hardwood forests

Abstract

The introduction of invasive, non-native earthworms into forest ecosystems has increased as recreational, industrial, and commercial activities increase in northern Ontario. The presence of these ecosystem engineers in previously uninvaded ecosystems has resulted in significant changes in soil structure, vegetation communities and soil organic carbon. In this study, field activities gathered samples of earthworms and soil from five different sites in the Thunder Bay district. Lab analysis was then completed to determine the relationships between ash-free dry mass of earthworms, total organic carbon, soil texture, pH and understory species richness. Results indicated that the presence of earthworms in northern boreal hardwood forest ecosystems has led to significant decreases in carbon storage of approximately 7%. This reduction in soil carbon storage may result in an increased release of carbon emissions and the reduction of the efficacy of the boreal forest as a critical global carbon sink.