Native Plant Community Structure Determines Invasibility by Weeds. (C03-allen656182-poster)
Authors:
P.S. Allen* - Brigham Young University A. Silvester - Brigham Young University
S.E. Meyer - USDA Forest Service Shrub Sciences Laboratory B. Roundy - Brigham Young University
Abstract:
Invasive weeds often compromise success of revegetation projects in the Western United States. In 2001, a long-term experiment was initiated to evaluate the ability for 12 restored native plant
communities (sagebrush steppe ecosystem) to resist invasion by exotic annual grasses. Variables in plant community structure included: high and low biodiversity (e.g., native grasses alone, or with native forbs and/or shrubs), high and low density, and early seral vs. climax species. The experiment was
hand-weeded through September 2002, simulating the efforts of restoration volunteers. Seeds of three exotic annuals (Bromus tectorum, Aegilops cylindrica, Secale cereale) were then seeded into the plots. In 2003, data taken included: percent cover by species, weed seed production, and resource utilization (soil water & nitrogen). Plant community biodiversity and density had a major impact on percent cover and seed production of annual grasses. Data the first year suggest that shrubs are critical in decreasing the competitive ability of exotic annual grasses. This study will continue for an additional ten years, providing long-term information about the most important exotic grasses threatening sagebrush steppe ecosystems.
Speaker Information: Phil Allen, Brigham Young University, Brigham Young University275 WIDB, Provo, UT 84602; Phone: 801-422-2421; E-mail: [email protected]
Session Information: Wednesday, November 5, 2003, 4:00 PM-6:00 PM Presentation Start: 4:00 PM (Poster Board Number: 611)
Keywords: native plants; invasive species; steppe ecosystem; plant communities