Establishment of the invasive perennial Vincetoxicum rossicum across a disturbance gradient in New York State, USA

Vincetoxicum rossicum (pale swallow-wort) is a non-native, perennial, herbaceous vine in the Apocynaceae. The species' abundance is steadily increasing in the northeastern United States and southeastern Canada. Little is known about Vincetoxicum species recruitment and growth. Therefore, we conducted a field experiment in New York State to address this knowledge gap. We determined the establishment, survival, and growth of V. rossicum during the first 2 years after sowing in two old fields subjected to four disturbance regimens. We hypothesized that establishment and survival would be higher in treatments with greater disturbance. At the better-drained location, overall establishment was 15 +/- A 1% [mean +/- A standard error] and did not differ among treatments. At the poorly drained location, establishment varied by treatment; mowed and control plots had greater establishment [10 +/- A 2%] than herbicide + tillage and herbicide-only plots [1.6 +/- A 0.5%]. Of those seedlings that emerged, overall survival was high at both locations (70-84%). Similarly, total (above + belowground) biomass was greater in herbicide + tillage and herbicide-only plots than in mowed and control plots at both locations. Thus, V. rossicum was successful in establishing and surviving across a range of disturbance regimens particularly relative to other old field species, but growth was greater in more disturbed treatments. The relatively high-establishment rates in old field habitats help explain the invasiveness of this Vincetoxicum species in the northeastern U.S. and southeastern Canada.