Author
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Ralphs, Michael |
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Submitted to: Wildland Shrub Symposium Proceedings
Publication Type: Proceedings Publication Acceptance Date: 12/30/2010 Publication Date: 1/1/2011 Citation: Ralphs, M.H. 2011. Broom Snakeweed Increase and Dominance in Big Sagebrush Communities. Natural Resources and Environmental Issues (Wildland Shrub Symposium Proceedings). 17(8). Interpretive Summary: Broom snakeweed is an invasive native sub-shrub that is widely distributed across rangelands of western North America. In addition to its invasive nature, it contains toxins that can cause death and abortions in livestock. It establishes in years of above average precipitation following disturbance by fire, drought or overgrazing. This allows widespread even-aged stands to develop that can dominate plant communities. Although its populations cycle with climatic patterns, it can be a major factor impeding succession of plant communities. Snakeweed can be controlled with prescribed burning and herbicides, however a weed-resistant plant community should be established and/or maintained to prevent its reinvasion. Technical Abstract: Broom snakeweed (Gutierrezia sarothrae (Pursh) Britt. & Rusby) is a native sub-shrub that is widely distributed on rangelands of western North America. It often increases to near monocultures following disturbance from overgrazing, fire or drought. Propagation is usually pulse driven in wet years, allowing large expanses of even-aged stands to establish and dominate plant communities. It can maintain dominance following fire, or can co-dominate with cheatgrass (Bromus tectorum L.) on degraded sagebrush rangelands. State-and-transition models show that competitive grasses in the respective plant communities can prevent snakeweed dominance. |
