April 30, 2015—The detrimental effects of invasive nonnative plants on the ecosystem are well-documented. However, the long-term influences on native plant diversity and abundance at the microsite scale are not as extensively studied. This information can help shape management efforts to support recovery of native plant communities.
An article in the journal Invasive Plant Science and Management examines the impact of Amur honeysuckle, a nonnative invasive species, on native plants at 12 mixed hardwood forest sites in Indiana. “Because combatting and slowing the spread of invasive shrubs starts by implementing treatments on small scales such as individual forests or woodlots,” said Joshua M. Shields, an author of the study, “it is important to understand the effects at such scales.”
The impact of invasive plants on ecosystems can be seen in a number of ways. It can result in less native diversity and growth, and can compromise the ecological and economical integrity of our natural resources. The sustained presence of invasive plants can have indirect effects, such as altering nutritional cycles and inhibiting fungal associates in native communities.
In this study, researchers examined how long the invading honeysuckle had been established, its density, and the amount of growing space it occupied. Researchers focused on the combined effects of duration and intensity of an invasive shrub on native plants.
The study sites with the greatest taxonomic diversity and density of native vegetation had the lowest percent cover of Amur honeysuckle. The percent cover of honeysuckle was negatively correlated with diversity, richness, percent cover, and woody seedling density of the native species. When considered along with percent cover, duration was not found to be a significant factor. However, when duration alone was considered, it was found to have a significant negative impact on native plant diversity and abundance.
The microsites where honeysuckle has persisted longest have a greater percent cover of the shrub, resulting in more light competition from above for native understory plants, thus reducing diversity and abundance of native flora. Understanding microsite diversity and the gradient of negative effects within a forest due to honeysuckle invasion is a tool managers can use to better prioritize control efforts and to identify and protect areas where native plants are most likely to recover.
Full text of the article “Influence of Intensity and Duration of Invasion by Amur Honeysuckle (Lonicera maackii) on Mixed Hardwood Forests of Indiana,” Invasive Plant Science and Management, Vol. 8, No. 1, January–March 2015, is now available.
About Invasive Plant Science and Management
Invasive Plant Science and Management is a broad-based journal that focuses on invasive plant species. It is published by the Weed Science Society of America, a non-profit professional society that promotes research, education, and extension outreach activities related to weeds; provides science-based information to the public and policy makers; and fosters awareness of weeds and their impacts on managed and natural ecosystems. For more information, visit http://www.wssa.net/.