NEAR-SURFACE SOIL NITROGEN AND VEGETATION RESPONSE TO INVASIVE EMERALD ASH BORER IN FORESTED BLACK ASH WETLANDS OF THE WESTERN UPPER PENINSULA, MICHIGAN, USA

Invasive emerald ash borer (EAB) (Agrilus planipennis Fairmaire) poses an imminent threat to the structure and function of North American hardwood forests, particularly black ash (Fraxinus nigra Marshall), and alters the hydrologic and ecological services of their wetlands. Black ash trees regularly grow in seasonally saturated soils and are responsible for hydrologic regulation and nutrient cycling. In this study, a gradient of black ash wetlands impacted by EAB were monitored to assess vegetation changes and near-surface soil nitrogen availability. Vegetation community changes were intertwined with nitrogen cycle disturbances following EAB infestation. As black ash died and fell to the wetland, more total organic nitrogen was returned to the environment and promptly incorporated into the growing shrub and sapling layers. Assessing vegetation and biogeochemical changes along an EAB gradient in the environment improves our understanding of the ecological ramifications for a future landscape without black ash wetlands as they presently exist