International Research Fellowship Program: Exotic Species Invasion: Direct and Indirect Interference in Native Species Persistence

Lyons Kelly G, Woodland CA

Investigators

Abstract

0202653 Lyons The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-two month research fellowship by Dr. Kelly G. Lyons to work with Dr. Alberto Burquez at the Universidad Nacional Autonoma de Mexico, in Hermosillo, Mexico. This project is designed to test the general hypothesis that the presence of an invasive, exotic plant species negatively affects native plant species with emphasis on documenting changes in native species abundance and separating the effects of direct and indirect interactions. Four studies will be conducted. Three of these will employ paired plots in invaded and non-invaded areas along an invasion front in intact, native habitat. A descriptive study (1) will test whether the presence of an exotic species adversely affects native species through direct and/or indirect means by correlating native and exotic species' abundance on either side of an invasion front. Two studies will employ descriptive and manipulative experiments to test the hypothesis that an aggressive exotic impacts native species' fitness indirectly by altering community food web dynamics and pollinator mutualisms. Finally, through experimental removal of an exotic, a fourth study will examine exotic species' effects on native species persistence. The investigation will take place in the Plains of Sonora subdivision in the Sonora Desert near Hermosillo, Sonora, Mexico where the aggressive perennial grass Pennisetum ciliare (L.) Link (buffelgrass) has been introduced for rangeland improvement. This exotic species is spreading from grazed areas into natural, intact habitats and is a widely perceived threat to native biodiversity. These studies are expected to demonstrate the role of exotic species invasions in the decline of native species abundance and fitness and highlight the more elusive, indirect mechanisms mediated by native pollinators and insect herbivores. Invasive species honor no boundaries, and this project will facilitate a dialogue between the U.S. and Mexico on this pressing conservation issue. Dr. Burquez specializes in pollination ecology, is an expert of plant biogeography and pollinator fauna of the region and has been documenting the spread of P. ciliare into native desert thornscrub for 6 years.