Impacts and management of Microstegium vimineum invasions
Luke Flory, Indiana University

Impacts and management of Microstegium vimineum invasions

Biological invasions have recently come to the forefront as a leading cause of global environmental change. Thus there is an urgent need to understand the community and ecosystem effects of invasions and how to manage and restore invaded habitats. To evaluate the effects of Microstegium vimineum (Japanese stiltgrass) invasions on native plant and arthropod abundance and diversity and forest succession, we conducted a long-term experimental invasion study. We also removed Microstegium from eight heavily-invaded sites across southern Indiana using multiple methods to determine the optimum method for eradicating invasions and restoring native habitats. Experimentally invaded plots had 38% lower diversity and up to 64% lower native herbaceous plant biomass, and 19% lower arthropod richness and 39% lower arthropod abundance than invader-free reference plots. Invaded plots also suffered reductions in the survival of some planted tree species and natural tree recruitment was over four times greater in reference plots, suggesting invasions can inhibit forest succession and alter the composition of tree species. Removing Microstegium with a grass-specific herbicide increased native species biomass and diversity and increased native tree recruitment by over 120%, but removal methods such as hand-weeding and pre-emergent herbicide were less effective for restoring native species. Our results show that Microstegium is causing significant declines in native species and inhibiting forest succession but that habitats can be restored by removing invasions using a grass specific herbicide. Natural areas managers should rapidly identify and remove Microstegium to conserve biodiversity and prevent further invasions.