Distribution and Ecology of Riparian Invaders in Kayaderosseras Creek and the Battenkill
Erin Kenison '09, Peter Leipzig-Scott '09, and Josh Ness, Department of Biology

Japanese knotweed is a highly invasive weed currently invading the riparian zones of the Kayaderossersas and Battenkill river systems. Our mapping of Knotweed in the Kayderossersas and Battenkill suggests that invaded sites become more common as river size and discharge rates increase (perhaps due to greater delivery of plant fragments by the river), and that the invasion potential varies with stream geomorphology (becoming greater in the depositional banks of meandering stream segments). Experiments in four invaded sites in the Kayderosseras watershed demonstrated that Knotweed is rarely attacked by herbivores (relative to attack rates in its native Japan) and that ant ‘bodyguards' alter the distribution of herbivory within plants. These ant guards become more common after knotweed is damaged, a response that may be attributable to damage-induced increases in the production of ant-rewards (sugary nectar) by the plant. We conclude that the knotweed invasion is facilitated by a readily available transportation network (flowing rivers) and a paucity of effective natural enemies.

Full report is not available. Please contact Josh Ness for more information.