Abstract
Invasive glossy buckthorn could reduce restoration potential for understory native forest herbs by compromising their growth and biodiversity. Few studies of glossy buckthorn’s effects on forest herbs exist, and none were done in early-successional, partially open hardwood forests. This study was conducted in a mature hybrid poplar plantation invaded by buckthorn, located in southeastern Québec. We tested the effect of buckthorn removal on the growth of three forest herb species, whether this effect varied among species, and if canopy type (two poplar clones) influenced this effect. Forest herbs were planted in herbicide (buckthorn removed) and control treatments in the plantation understory, an environment similar to that of early-successional hardwood forests. Over the first two growing seasons, species showed specific reactions to buckthorn cover. Mean relative growth rate (RGR) for Asarum canadense and Polygonatum pubescens was increased in the herbicide treatment (48% and 33%, respectively) and decreased in the control treatment (−35% and −33%, respectively). Sanguinaria canadensis growth was the highest among species, with no difference between treatments. No effects of canopy type were detected. Results suggest that planting forest herbs for restoration purposes may be unsuccessful if buckthorn is present. Important changes in understory flora biodiversity are likely to occur over the long term in forests invaded by buckthorn.
Highlights
Exotic species represent from a quarter to a third of the plant species of the eastern Canadian provinces and American states [1]
Our results indicate that buckthorn appears to be interfering with forest herb growth, and the different species tested seem to be differently affected. If this trend of a differential effect of buckthorn on forest herb species is confirmed in the future, important changes in understory herbaceous flora biodiversity will likely occur over the long term
Considering that transplantation studies have yielded contradictory results [29,35,39], and that success rate seems to decline when observed over a period which is closer to the long life expectancy of forest herbs [35], our results bring support for a removal of buckthorn prior to establishing transplanted forest herb populations, for a choice of species with ecological requirements matching those of planting sites, and of transplants that are larger in size to maximize the potential for success
Summary
Exotic species represent from a quarter to a third of the plant species of the eastern Canadian provinces and American states [1]. An exotic species can be a driver of change in its new environment, or it can be a “passenger” taking advantage of the current state of an ecosystem, such as following a disturbance [7]. In the latter case, control efforts would not be justified because the opportunistic species is not the primary source of the negative effects and its eradication will probably not restore the ecosystem and its biodiversity. It is necessary to experimentally test the effects of invasive exotic plants to verify causal links between the effects observed and their presence and abundance, and prioritize the monitoring and control of species for which a causal link has been established [9]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
