Following their introduction, invasive plants often gain an initial advantage by escaping natural enemies in their native range. In attempts to minimize the spread of invasive plants, native-range enemies are sometimes deliberately released into the invaded range as a method of biological control. However, populations of the invasive plant may be able to escape attack from these enemies by means of population isolation. Using the study organism Canada thistle (Cirsium arvense), I will be investigating whether herbivory declines with distance from existing populations by creating experimentally isolated plots of C. arvense. The goals of this project is to determine if population isolation can act as a mechanism of escaping enemy pressure, and what the impact is on plant performance. This will be framed as a multi-year experiment which will allow me to determine the rate of insect colonization in isolated populations, and whether or not colonization a fair predictor of herbivore persistence for future growing seasons.
Principal Investigator: Peter Kotanen