Response of the forest floor invertebrate community to canopy gap formation caused by early stages of emerald ash borer-induced ash mortality

Emerald ash borer (EAB; Agrilus planipennis) is an invasive wood-boring beetle that causes rapid ash tree mortality, widespread formation of canopy gaps, and accumulation of coarse woody debris (CWD) in forests. The objective was to quantify the effects of canopy gaps, ash CWD and their interaction caused by EAB-induced ash mortality on the forest floor invertebrate community. A two-year manipulative experiment was conducted in forests at NASA Plum Brook Research Station in Ohio, USA. Canopy gaps caused by ash mortality decreased the activity-abundance of some taxa, such as Opiliones, Carabidae and several families of Collembola, as well as invertebrate richness and diversity, but had minor effects on community composition. CWD had minimal effects on the forest floor invertebrate community overall, but altered the activity-abundance of several invertebrate groups, and marginally increased taxonomic evenness in closed canopy treatments. The results of this study suggest that the effects of ash mortality on forest floor invertebrate communities change over time due to an inverse temporal relationship in magnitude effects of canopy gaps, which diminish over time, and accumulation of CWD, which increases over time. These findings contribute to our understanding of the effects of disturbance on ecosystems and the cascading ecological impacts of emerald ash borer invasions in forests.