Population and community responses to invasive species management 

Plant community responses to removal of an invasive

Invasive plant species can significantly alter community composition relatively quickly and recruitment rates of native species can be limited by the local seed bank and dispersal capabilities. Therefore, invasive plant removal is expected to lead to novel species compositions and interactions because recolonization is likely driven by a small number of plant species occurring at higher densities than those present in previously uninvaded areas. Therefore, understanding how plant species will respond to release from the effects of the introduced dominant competitor is not as easy to predict as we would like. In collaboration with the Emry lab at Washburn, we have been investigating plant community response to small scale removal of the Amur honeysuckle, Lonicera maackii (Rupr), a woody shrub native to northeastern Asia.

Unintended population responses to removal of an invasive

Efforts to reduce the impact of invasive species often involve fairly intensive interventions to rapidly remove the invasive without any post removal strategies. These interventions are often necessary and strongly encouraged, but can also lead to unintended consequences, which ma be prevented. For example, management of the Amur honeysuckle, Lonicera maackii, often involves rapid removal of the invasive plant which can stimulate the rapid growth of a small number of native plant species and their herbivores. How this rapid growth may affect plant-insect interactions is not well understood, and unintended consequences may arise. The lab has been focusing on how the removal of of the Amur honeysuckle, Lonicera maackii, may have altered the interactions between a specialist moth, the Asimina webworm moth, it's host, the common Paw Paw, and natural enemies. In particular, we have been assessing the how the rapid increase in paw paw density following honeysuckle removal led to an outbreak of the Asimina webworm moth which altered the survival of paw paw patches and parasitism rates of the  Asimina webworm moth. 

Selected Relevant Publications (Please contact me for reprints):

Emry,D.J., R.J. Mercader, P.E. Bergeron, J.V. Eilert, and B.A. Riddle. 2024. Small-scale amur honeysuckle removal and passive restoration may not create long-term success. Natural Areas Journal. 44(2):98-103. 

Mercader, R.J., L.R. Apenfeller, P.O. McCoy, T. Sadikot, and J.L. Smith. 2022. Parasitoid increase during and outbreak of a native herbivorous insect following small-scale amur honeysuckle (Lonicera maackii) removal. The American Midland Naturalist. 188(1):127-134.

Mercader, R.J., T.J. Paulson, P.J. Engelken, and L.R. Appenfeller. 2020. Defoliation by a native herbivore, Omphalocera munroei, leads to patch size reduction of a native plant species, Asimina triloba, following small-scale removal of the invasive shrub, Amur honeysuckle, Lonicera maackii. Plant Ecology 221:125–139.