PARENT SESSION
Wednesday, August 9, 1:30-5:00 pm
COS 69 - Disease ecology IV: transmission and land use
L-4, Lobby Level, Cook Convention Center
Presiders: J Brunner and A Radomski

Pathogen-induced reversal of native perennial dominance in a grassland community.

Hosseini, Parviez^*,1, Borer, Elizabeth², Seabloom, Eric², Dobson, Andy¹, ¹ Department of Ecology and Evolutionary Biology, Princeton, NJ, USA² Department of Zoology, Corvallis, OR, USA

ABSTRACT- Invasion is a critical threat to biodiversity, but the role of disease in invasion has received relatively little attention. Although many hypotheses have been proposed to explain one of the most extensive plant invasions in the world, invasion and domination of historically perennial grasslands in California [USA] by exotic annual grasses, disease has never been quantitatively assessed as a potential cause of this invasion. Using a model parameterized with field-estimated values, we demonstrate that pathogen presence in this system was necessary to reverse competitive dominance and allow annual grass invasion. This type of pathogen-mediated reversal in competitive balance may be critically important for understanding current and future invasions.

Key words: disease, invasion, Poaceae