PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Persistence of invading gypsy moth populations in the United States.
Whitmire, Stefanie *,1, Tobin, Patrick2, 1 University of Puerto Rico, Mayaguez, PR, United States2 USDA Forest Service Northeast Research Station, Morgantown, WV, United States
ABSTRACT- Exotic invasive species are a mounting threat to native biodiversity, and their direct and indirect effects are gaining increasingly more attention at each detection. Equally important are the dynamics of those exotic invasives that are already well-established and for whom eradication is no longer possible. While the literature reports many examples of the ability of a newly-arrived exotic invader to persist prior to detection and population growth, we focused on the persistence dynamics of an established invader using the European gypsy moth in North America as a model system. The spread of gypsy moth is largely thought to be the result of the growth and coalescence of isolated colonies ahead of the generally infested area. One important question is thus the ability of these isolated colonies to persist when subject to Allee effects and/or inimical stochastic events. We used U.S. gypsy moth survey data, collected from pheromone-baited traps within the transition zone, to estimate the Local Indicator of Spatial Autocorrelation. This novel spatial statistical tool was used to objectively identify isolated colonies of gypsy moth. We then determined region-specific probabilities of colony persistence given the population abundance in the previous year and its relationship to a suite of ecological factors. We observed that colonies in Wisconsin, U.S., were significantly more likely to persist in the following year than in other geographic regions of the U.S. transition zone. Moreover, across all regions, the abundance of preferred host tree species and land use category did not appear to influence persistence. The enhanced rates of persistence in Wisconsin may help explain the more rapid rate of spread in this region, and motivates important questions regarding the management of established exotics as they invade new areas.
Key words: gypsy-moth, invasive, persistence