Removal of the Invasive Shrub, Lonicera maackii (Amur Honeysuckle), from a Headwater Stream Riparian Zone Shifts Taxonomic and Functional Composition of the Aquatic Biota

Riparian plant invasions can result in near-monocultures along stream and river systems, prompting management agencies to target invasive species for removal as an ecological restoration strategy. Riparian plant invaders can alter resource conditions in the benthos and drive bottom-up shifts in aquatic biota. However, the influence of management activities on the structure and function of aquatic communities is not well understood. We investigated how removal of a riparian invader, Lonicera maackii (Amur honeysuckle), influenced aquatic macroinvertebrate community functional and taxonomic diversity in a headwater stream. We hypothesized that removal of L. maackii from invaded riparia would result in (H 1 ) increased aquatic macroinvertebrate abundance, density, and diversity; (H 2 ) a taxonomic and functional shift in community composition; and, in particular, (H 3 ) increased functional diversity. Aquatic macroinvertebrates were sampled monthly from autumn 2010 to winter 2013 in headwater stream riffles with a dense riparian L. maackii invasion and those where L. maackii had been experimentally removed. We found macroinvertebrate density was significantly higher in the L. maackii removal reach (