Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2003
Publication Date: N/A
Technical Abstract: To manage nonindigenous plant invasions, mechanisms of invasion resistance must be identified and modified as a portion of management. One mechanism is that functionally diverse plant assemblages use resources more completely. We investigated the ability of three desirable plant species with different spatial and temporal growth patterns to resist invasion by a nonindigenous species, Centaurea maculosa (spotted knapweed). Niche differentiation between desired species was quantified using their relative competitive coefficients. Centaurea maculosa recruitment was negatively related to desired species richness. In more diverse, native plant communities, we investigated the ability of functional groups to resist invasion by C. Maculosa and quantified resource use by indigenous functional groups and the invader. This study suggested that establishing and maintaining a diversity of plant functional groups within the community enhances resistance to invasion. Forbs were particularly important to resisting invasion because the indigenous and nonindigenous forbs are functionally similar. Understanding and identifying which functional groups, combinations of functional groups, or key species resist invasion by nonindigenous species through niche complementarity and resource preemption is critical for management and restoration. Because a generalized objective for invasive plant management is to establish and maintain invasion resistant plant communities that meet other land-use objectives, we have reestablished diverse indigenous communities in various restoration projects. Our restoration research in invasive plant dominated lands included testing seeding methods (drill, broadcast, seed island), seed bed preparation, herbicide treatments, and seed mixtures with varying functional diversities. Establishing and maintaining diverse, weed resistant plant communities must be a major goal of all integrated weed management programs.