Seed-Dispersal Ability of the Invasive Perennial Vines Vincetoxicum nigrum and Vincetoxicum rossicum

Abstract Black swallowwort [Vincetoxicum nigrum (L.) Moench] and pale swallowwort [Vincetoxicum rossicum (Kleopow) Barb.] are perennial vines of European origin that invade natural areas and perennial cropping systems in the northeastern United States and southeastern Canada. Both species reproduce via wind-dispersed seeds in the form of achenes with comas, but little is known about the extent of dispersal of these seeds. We studied the relationship of seed release height (0.75m, 2 m), wind speed at the time of release, seed mass, and settling rate on distance traveled. Vincetoxicum nigrum and V. rossicum seeds traveled up to 72.1 and 79.6 m, respectively. Seeds of both species released from 2m traveled greater distances than seeds released from 0.75m, which fell within 20m of the release point. Release height was the most important factor influencing long-distance dispersal events. Wind speed also strongly interacted with release height for longdistance dispersal of V. nigrum. Vincetoxicum nigrum seed ma...