PARENT SESSION
Friday, August 11, 8:00-11:30 am
COS 104 - Invasive species VII: prevention, control, and models
Ballroom E, Ballroom Level, Cook Convention Center
Presiders: T Langkilde
Altering the scale of grazing selectivity to limit invasion of exotic forages in grasslands.
Cummings, D. Chad *,1, Fuhlendorf, Samuel1, Hickman, Karen1, Engle, David2, 1 Oklahoma State University, Stillwater, OK, USA2 Iowa State University, Ames, IA, USA
ABSTRACT- Introduced forage species planted as monocultures often possess traits that promote persistence under intense grazing by domestic and native herbivores. Rapid maturation, secondary chemicals, and fungal associations are among the traits that enhance persistence and can facilitate dominance over native plants that are preferentially selected by native and domestic herbivores. Forages native to North American evolved under a fire-grazing interaction (i.e., the evolutionary disturbance pattern) whereas many introduced forage plants evolved under heavy grazing pressure without the fire interaction. In recent studies that restore the fire-grazing interaction to North American grasslands, fire is applied to discrete portions of the landscape and grazers congregate and intensively graze recently burned patches but avoid unburned areas. Scale of forage selection is altered from individual species to entire patches and the interaction increases biodiversity and limits the spread of an exotic, invasive forage species. These preliminary results suggest that native species might be better adapted to the evolutionary disturbance pattern than the introduced forage species that are invading under traditional management that lacks the evolutionary disturbance pattern. Therefore, our goal is to focus on the plant-herbivore interactions of invasive forage species in diverse native plant communities and the evolutionary disturbance pattern created by the fire-grazing interaction that alters livestock selectivity and competitive relationships among plants. We will focus on functionally different introduced forage species, all invading native grasslands and all adapted to grazing through mechanisms that limit palatability. We will present data on invasion dynamics for one species in two fire and grazing regimes and provide a conceptual model for changing grazing selectivity with fire to minimize exotic species invasions.
Key words: Lespedeza cuneata , invasive species ecology, grazing behavior