Does Disturbance Similarly Facilitate Weed Invasion Within Grass, Forb, and Shrub Plots?

Authors: Monaco, Thomas; LEONARD, E - UTAH STATE UNIVERSITY

Submitted to: Grasslands
Publication Type: Book / Chapter
Publication Acceptance Date: 5/12/2008
Publication Date: 6/12/2008
Citation: Monaco, T.A., Leonard, E.D. 2008. Does Disturbance Similarly Facilitate Weed Invasion Within Grass, Forb, and Shrub Plots?. Grasslands.

Interpretive Summary: The importance of disturbance to mediating weed invasion is clearly corroborated by our results. The capability of the long-lived perennial grass (Agropyron) to resist invasion appears to be associated with greater biomass productivity. In contrast, high susceptibility to weed invasion of Achillea plots was due to significantly greater amounts of underutilized above and belowground resources (Davis et al. 2000). Our results agree with the general contention that disturbance events increase available resources or safe sites for weed invasion. Perennial grasses appear to be a necessary component of minimizing underutilized resources. Our results also emphasize that managerial efforts to reduce the recurrence of disturbance events should be a primary goal to reduce the impacts and prevent continual dominance of invasive annual species in the sagebrush-steppe ecosystems of the Great Basin.

Technical Abstract: Big sagebrush communities (Artemisia tridentata Nutt.) in the Great Basin have been degraded by the synergistic consequences of chronic disturbance and annual weed invasion (Young and Evans 1978). Repairing ecosystem function is an overarching goal of restoration efforts, but it remains unclear which species most effectively resist weed invasion and how disturbance mediates weed invasion. We evaluated whether disturbance similarly facilitates invasion in single-species grass, forb, and shrub plots.