Removing Invasive Lonicera maackii and Seeding Native Plants Alters Riparian Ecosystem Function

Abstract

Lonicera maackii (Amur honeysuckle) is known to dominate the shrub layer of forests, resulting in a dramatic decrease in ground cover, species diversity, and changes in ecosystem processes such as decomposition. Land managers have been removing L. maackii for some time now, but few studies have examined the potential for reinvasion of a restored site. We measured the plant community and ecosystem function in a restored forest and field (L. maackii removal and seeding of native plants) and in a control forest (L. maackii dominating), along an urban riparian stretch, five through seven years after L. maackii restoration. We found that removing L. maackii, along with modest efforts to re-introduce native grasses and forbs, can result in a shift in the plant community and some ecosystem properties and processes. Restored sites had higher species richness, greater available soil nitrogen, and faster nitrogen mineralization rates. We also found lower soil pH and that more soil organic matter accumulated over time in the restored treatments. While we found that removal of L. maackii and seeding of native plants can lead to a change in some ecosystem processes within ten years in riparian forests, we encourage scientists and managers to continue efforts on longer-term studies to better understand ecosystem structure and function after removal of the invader.