9610306 Case An important issue in conservation biology is how native species respond to disturbance and invasions by exotic species. Since the invasion of California by the Argentine ant (Linepithema humile) nearly 100 years ago, many studies have addressed the impact of L. humile on the native ant community. However, the implications of such a change on the rest of the community have still not been examined. Preliminary work has shown that the Argentine ant is extremely abundant in upland scrub habitats (coastal sage scrub and chamise-chaparral) in coastal southern California. The coastal horned lizard, an ant specialist and sensitive species for the state of California, was absent from the small fragments surveyed and only found in areas without the Argentine ant in larger unfragmented areas. This research will consist of a series of experiments to determine which factors facilitate the invasion of the Argentine ant in to natural habitats and measure the impact of the invasion on various trophic levels throughout the community. Specifically, the investigator will test the hypotheses that 1) habitat modification facilitates the invasion of an exotic species, 2) the Argentine ant through exploitation and interference competition affects not only other arthropods, but vertebrates as well and 3) the native ant community will return to a pre-invasion state with the thorough removal of Argentine ants. These studies will provide information for the control of this exotic pest as well as help determine management guidelines for the preservation of sensitive habitat and species therein.
