Spring Floral Community in a Kentucky Forest Influenced by Amur Honeysuckle (Lonicera maackii) Density and Removal

Abstract

Amur honeysuckle (Lonicera maackii) is an invasive shrub introduced to the U.S. in the late 1800s for ornamental use. Since its introduction, it has spread throughout the eastern U.S., becoming especially problematic in urban and peri-urban forest fragments. Once introduced in an ecosystem, L. maackii establishes a dense thicket that restricts understory light and alters understory plant communities. This study monitored the flowering early spring floral community in forests with varying densities of L. maackii (high, low, and no-density) before and after L. maackii removal in Raven Run Nature Sanctuary, a natural area on the outskirts of Lexington, KY, U.S. In plots from which L. maackii was removed, we documented higher flowering spring flora abundance (102–125%), diversity (32%), and richness (47%) compared to plots from which L. maackii was not removed. While abundance did not vary with prior L. maackii density, diversity and richness were 40% and 53% higher, respectively, in plots with low prior L. maackii density than high prior L. maackii density. Finally, flowering plant assemblages were similar across prior L. maackii density (low vs. high) but differed with L. maackii removal treatment (removed vs. unremoved and no L. maackii vs. removed). Flowering spring plants quickly recover after L. maackii removal, but some residual effects of L. maackii continue to structure understory plant communities even after removal. Early removal of. L. maackii from invaded stands and continued management to prevent re-introduction are essential to support recovery of diverse understory plant communities in affected forests.