Recovery of native plant communities in southwest Ohio after Lonicera maackii removal

Lonicera maackii (Rupr.) Herder (Amur honeysuckle) is one of the most important invasive plants in the Ohio Valley. Because of its phenology and dense canopy, L. maackii can exclude native herbs and interfere with regeneration of woody plants. In 2005, in a county park in southwest Ohio, I established modified Whittaker plots in four stands with a gradient of L. maackii cover ranging from 24 yr old to 40 yr old. The L. maackii canopies were removed by herbicides in fall 2005. Plant cover was monitored from 2005 to 2013. After 8 yr, there was an increase in species richness and herbaceous cover at all sites. Herbaceous species turnover was generally greater at sites with greater initial L. maackii cover. All of the most-common herbaceous species increased or maintained their coverage; most of the species that increased were those that bloom in late spring or summer. The abundances of other invasive species also increased, including Alliaria petiolata (M. Bieb.) Cavara & Grande (garlic mustard). However, A. petiolata abundance peaked 2-6 yr after L. maackii removal, suggesting that this increase, frequently seen after L. maackii removal, may be transitory. Previous studies have not shown such a decline after an initial increase in A. petiolata, but few studies have extended over this length of time. Ash (Fraxinus L.) decline caused by the emerald ash borer may now be affecting the recovery of these stands.