Management of invasive Allee species

Abstract

In this study, we use a discrete, two-patch population model of an Allee species to examine different methods in managing invasions. We first analytically examine the model to show the presence of the strong Allee effect, and then we numerically explore the model to test the effectiveness of different management strategies. As expected invasion is facilitated by lower Allee thresholds, greater carrying capacities and greater proportions of dispersers. These effects are interacting, however, and moderated by population growth rate. Using the gypsy moth as an example species, we demonstrate that the effectiveness of different invasion management strategies is contextdependent, combining complementary methods may be preferable, and the preferred strategy may differ geographically. Specifically, we find methods for restricting movement to be more effective in areas of contiguous habitat and high Allee thresholds, where methods involving mating disruptions and raising Allee thresholds are more effective in areas of high habitat fragmentation. ARTICLE HISTORY

Novel insights on population and range edge dynamics using an unparalleled spatiotemporal record of species invasion

“…Allee effects in particular have gained attention as an important consideration for management against invasive species establishment and spread, where different management tactics can have interacting effects on low‐density population dynamics (Blackwood et al., ; Suckling, Tobin, McCullough, & Herms, ). A recent theoretical study demonstrated how geographic variation in the strength of Allee effects in gypsy moth may affect the optimal management strategy (Chan, Kent, & Johnson, ). Estimations of the Allee threshold can provide target densities below which the population is unlikely to persist.…”