Santa Cruz Island Reserve

26 Aug, 05 AM - 17 Sep, 05 AM

The removal of the Argentine ant (Linepithema humile) from Santa Cruz Island (SCI) will provide an unparalleled opportunity to address how invasive species restructure arthropod food webs in the absence of anthropogenic disturbance. The SCI removal effort will allow the processes of invasion to be examined at a large scale and in reverse ? an especially powerful experimental approach to quantify the direct and indirect effects of invasions. In particular, the removal of the Argentine ant from scrub and riparian habitats on SCI will (1) clarify processes underlying the disappearance of native ants from areas where L. humile becomes abundant, and (2) reveal qualitative and quantitative changes in the structure and composition of food webs. With respect to the latter point, mutualisms between ants and honeydew-producing insects are of special interest. Because these ubiquitous interactions provide L. humile with plant-based, carbohydrate resources that fuel high rates of colony growth, they may thus magnify invasion impacts. The long-term nature of the research proposed here will serve as a key check on the removal effort and directly coincides with the long-term management goals of The Nature Conservancy and the National Park Service. This summer, prior to the control effort to be launched by TNC in the summer of 2011, I want to set up a series of paired invaded - uninvaded plots centered in the three main infested areas (Field station, Navy site, and Valley anchorage). I was thinking that the Navy and field station sites would each provide one pair of sites and the much larger Valley Anchorage area would provide three pairs of sites. I may add additional control sites as needed. The idea would be to match sites within each pair for perennial vegetation and topography. Each plot would be approximately 30 m X 30 m. Preliminary data to be collected in each plot this year would be an estimate of native ant colony density and diversity. I am also interested in the extent to which ants are using honeydew-producing insects on oaks and perhaps other plant species. I would selectively collect representatives of these other insects. I plan to follow these plots each year at about the same season to determine how native ants recolonize as the Argentine ant retreats. The position of invaded plots would be as close to the perimeter of the invaded areas as possible because these areas should be the first areas to receive intense chemical control.

Visit #22402 @Santa Cruz Island Reserve

Approved

Under Project # 22248 | Research

Recovery of island food webs following Argentine ant removal from Santa Cruz Island

faculty - University of California, San Diego

Reservation Members(s)

David Holway Aug 26 - Sep 17, 2010 (23 days)

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Dorm 1 Aug 26 - Sep 17, 2010
Pickup Truck 1 Aug 26 - Sep 17, 2010