PARENT SESSION
Poster Session 35: Restoration Ecology.
Thursday, August 5 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Identification of North American plants that are relatively insensitive to the Centaurea maculosa allelochemical (-)-catechin.
Perry, Laura*,1, Paschke, Mark2, Vivanco, Jorge1, 1 Department of Horticulture and Landscape Architecture, Fort Collins, CO, USA2 Department of Forest, Rangeland, and Watershed Stewardship, Fort Collins, CO, USA
ABSTRACT- Recent evidence indicates that Centaurea maculosa (spotted knapweed) invasions in the western U.S. are mediated by C. maculosa root exudation of (-)-catechin, a potent phytotoxin. In attempts to reclaim C. maculosa infested sites, persistence of (-)-catechin in the soil following C. maculosa removal likely interferes with reestablishment of native vegetation. Identification of native North American species that are less sensitive to (-)-catechin is necessary to inform the choice of species for establishing plant cover, controlling erosion, and reducing C. maculosa reinvasion in reclaimed sites. We evaluated effects of six (-)-catechin concentrations on germination of 25 North American rangeland species, including 11 species that have been observed in North American C. maculosa stands, and 14 species commonly used in restoration of western U.S. grasslands. (-)-Catechin concentrations included the full array of concentrations observed in C. maculosa stands in the field, ranging from 31.25 to 1000 
g ml-1. Initial analyses indicate substantial variation among species in sensitivity to (-)-catechin, with the concentration required for inhibition as low as 125 g ml-1 for more sensitive species and as high as 500 g ml-1 for insensitive species. These data allow us to suggest seed mixes with a greater likelihood of revegetation success. Further, observed differences in (-)-catechin sensitivity among species suggest a potential for native plant community composition to influence vulnerability to C. maculosa invasion. Finally, trends in sensitivity among functional groups could be used to predict the (-)-catechin sensitivity of additional species.
Key words: allelopathy, germination inhibition, Centaurea maculosa, revegetation