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United States Department of Agriculture

Agricultural Research Service

Research Project: Invasive Species Assessment and Control to Enhance Sustainability of Great Basin Rangelands

Location: Great Basin Rangelands Research

Title: Cheatgrass invasion and woody species encroachment in the Great Basin: benefits of conservation

Authors
item Weltz, Mark
item Spaeth, Ken -
item Taylor, Michael -
item Rollins, Kimberly -
item Pierson, Frederick
item Jolley, Leonard -
item Nearing, Mark
item Goodrich, David
item Hernandez, Mariano -
item Nouwakpo, Savjro -
item Rossi, Colleen -

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2014
Publication Date: March 20, 2014
Citation: Weltz, M.A., Spaeth, K., Taylor, M.H., Rollins, K., Pierson, F., Jolley, L., Nearing, M., Goodrich, D., Hernandez, M., Nouwakpo, S.K., Rossi, C. 2014. Cheatgrass invasion and woody species encroachment in the Great Basin: Benefits of conservation. Journal of Soil and Water Conservation. 69(2):39A-44A.

Interpretive Summary: The Great Basin is the largest North American desert covering more than 122.5 million acres. Two of the biggest threats to ecosystem stability and integrity in the Great Basin are invasive annual grasses and expansion of native woody plants. The alteration of native plant communities by these invasive species has increase the likelihood of damaging and dangerous wildfires. Relatively few studies have estimated the economic benefits of conservation for rangeland systems threatened by invasive annual grasses or invasive woody plants. Recent studies have integrated rangeland Sate and Transition Models into economic-ecological simulation models, and used these integrated models to estimate the benefits of conservation in terms of wildfire suppression costs savings. By considering wildfire suppression cost savings, and ignoring other ecosystem services, these studies necessarily understate the economic benefits of conservation. In order to provide a full-accounting of the economic benefits of conservation on rangeland that is threatened by invasive plants, further research is needed to quantify how ecosystem services, such as wildlife habitat, forage for livestock, recreation opportunities, and erosion control, change as a consequence of annual grass invasion and woody plant encroachment. Given current and impending economic impacts of the intertwined invasive plant and wildfire cycle on private and public lands across the West, large landscape-scale adaptive management approaches are needed to impede exotic annual grass and native tree species expansion before entire landscapes are degraded and destabilized. Unfortunately, few conventional cheatgrass eradication methods have been shown to be effective or practical for widespread application. The most cost-effective conservation is prevention, i.e., the early detection and eradication of exotic annual grasses such as cheatgrass. Additional research on cost-effective conservation and management measures to prevent expansion of cheatgrass and pinyon and Juniper woodlands and reduce damages where it is already established is needed to protect and enhance rangeland ecosystem services.

Technical Abstract: The Great Basin is the largest North American desert covering more than 122.5 million acres. Two of the biggest threats to ecosystem stability and integrity in the Great Basin are invasive annual grasses and expansion of native woody plants. The alteration of native plant communities by these invasive species has increase the likelihood of damaging and dangerous wildfires. The immediate costs of large wildland fires can exceed $20 million, but economic impacts extend beyond control of wildfires. Billions of dollars have been spent on wildfire suppression and millions on post-fire mitigation. The focus of our article is to illustrate how Ecological Site Descriptions can be used to guide conservation. The article discusses the economic and environmental benefits of conservation on rangelands. For Wyoming sagebrush steppe communities we found that fuel treatment is economically justified in terms of wildfire suppression cost savings only before cheatgrass has become established with expected net benefits in terms of wildfire suppression costs averted of $272 per acre. In the mountain big sagebrush system, the expected net benefits of conservation treatments to prevent wildfires range from $90 per acre to $358 per acre depending on density of pinyon and Juniper species and if cheatgrass is present. Following conservation soil erosion was reduced on Wyoming sagebrush sites by 3 fold and up to 10 fold on mountain sagebrush sites. The actual impact of a site being converted to cheatgrass will depend on the difference in canopy and ground cover between the sites and will vary annually depending on climate. The most cost-effective conservation is prevention, i.e., the early detection and eradication of exotic annual grasses such as cheatgrass and prevention of wildfires. Additional research on cost-effective conservation and management measures to prevent expansion of cheatgrass and pinyon and Juniper woodlands and reduce damages where it is already established is needed to protect and enhance rangeland ecosystem services.

Last Modified: 10/30/2014
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