Tuesday, August 7, 2007 - 8:00 AM

COS 24-1: Invasive ants alter invertebrate communities and ecosystem processes in an African rainforest

Amy E. Dunham, Smithsonian Institution and Alexander S. Mikheyev, University of Texas.

Understanding the ecosystem level impacts of invasive species is crucial for both the conservation and successful restoration of communities and ecosystem function.  Tropical rainforest ecosystems are threatened worldwide by development and deforestation and invasive species present an additional threat by altering ecological processes through direct alteration of the environment or indirectly through changes in communities and trophic structure. The small fire ant, Wasmannia auropunctata, a native of Central and South America has been spreading invasively throughout central African rainforests and elsewhere as a result of anthropogenic activities such as logging and oil extraction.  Little is known about the effect of this invasive species on native invertebrate communities or on ecosystem processes.  We examined how fire ant invasion affects invertebrate communities, herbivory levels, leaf chemistry, and nutrient cycling in 19 separate invasion fronts spreading from forest clearings within an oil concession in the rainforest of Gabon. Results suggest that presence of this exotic ant dramatically alters abundance and diversity of native invertebrates on the forest floor and changes herbivore communities with consequences for both nutrient regimes and herbivory levels.