Vincetoxicum rossicum (European swallowwort).
Abstract V. rossicum is a herbaceous perennial climbing vine native to Ukraine and southwestern European Russia. It was introduced into North America for ornamental purposes and has spread extensively throughout the lower Great Lakes Basin, particularly Lake Ontario, including New York State, USA and Ontario, Canada. Self-fertility and large numbers of wind-borne seeds ensure rapid dispersal of V. rossicum to new sites. Small patches of V. rossicum can coalesce to form very large, monospecific stands which can outcompete native vegetation resulting in a change in habitats and a decrease in biodiversity. V. rossicum is allelopathic and can alter the microbial composition in the rhizosphere preventing the growth of sensitive plant species. In the USA, competition from V. rossicum is putting pressure on the rare and endangered species Asplenium scolopendrium var. americanum. In addition to this, V. rossicum has been shown to decrease insect biodiversity and may have negative impact on the reproduction of the Monarch butterfly, Danaus plexippus.