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United States Department of Agriculture

Agricultural Research Service

Research Project: Assessment, Conservation and Management of Rangelands in Transition

Location: Northwest Watershed Management Research

Title: A synopsis of short-term responses to alternative restoration treatments in sagebrush-steppe: the SageSTEP project

Authors
item Mciver, James -
item Brunson, Mark -
item Bunting, Steve -
item Chambers, Jeanne -
item Doescher, Paul -
item Grace, James -
item Hulet, April
item Johnson, Dale -
item Knick, Steve -
item Miller, Richard -
item Pierson, Frederick
item Pyke, David -
item Rau, Benjamin
item Rollins, Kim -
item Roundy, Bruce -
item Schupp, Eugene -
item Tausch, Robin -
item Williams, Christopher

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2014
Publication Date: N/A

Interpretive Summary: Woody plant encroachment and annual grass invasions have altered the ecological structure and function of much of the rangelands in the intermountain western US. Land managers throughout the western US are seeking more information on the impacts of various conservation practices targeting woody plant encroachment and annual grass invasions. This report summarizes short-term results of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP) aimed at evaluating the ecological effects of multiple conservation practices designed to reduce woody fuels and to stimulate productivity of sagebrush steppe communities. The results demonstrate that tradeoffs (desirable outcomes for some attributes, undesirable for others) are inevitable when managing complex natural systems and that use of a consistent evaluation process, linked to monitoring, may be the best chance managers have for addressing woodland expansion and annual grass invasion. The results provide a useful resource for land managers considering management alternatives on western rangelands subject to woodland encroachment or annual grass invasion.

Technical Abstract: The Sagebrush Steppe Treatment Evaluation Project (SageSTEP) is an integrated long-term study that evaluates ecological effects of alternative treatments designed to reduce woody fuels and to stimulate the herbaceous understory of sagebrush steppe communities of the intermountain west. This synopsis summarizes results through three years post-treatment. Woody vegetation reduction by prescribed fire, mechanical treatments, or herbicides initiated a cascade of effects, beginning with increased availability of nitrogen and soil water, followed by increased growth of herbaceous vegetation. Response of butterflies and magnitudes of runoff and erosion closely followed herbaceous vegetation recovery. Shrub, biological soil crust, and tree cover, surface woody fuel loads, and sagebrush-obligate bird communities will take longer to fully express. In the short-term, cool wet sites were more resilient than warm dry sites, and resistance was mostly dependent on pre-treatment herbaceous cover. At least 10 years post-treatment time will likely be necessary to determine outcomes for most sites. Mechanical treatments did not serve as surrogates for prescribed fire in how each influenced the fuel bed, the soil, erosion, and sage-obligate bird communities. Woody vegetation reduction by any means however, resulted in increased availability of soil water, higher herbaceous cover, and greater butterfly numbers. We identified several tradeoffs (desirable outcomes for some variables, undesirable for others), involving most components of the study system. Tradeoffs are inevitable when managing complex natural systems, and they underline the importance of asking questions about the whole system when developing management objectives. Substantial spatial and temporal heterogeneity in sagebrush steppe ecosystems emphasizes the point that there will rarely be a 'recipe' for choosing management actions on any specific area. Use of a consistent evaluation process, linked to monitoring, may be the best chance managers have for arresting woodland expansion and cheatgrass invasion that may accelerate in a future warming climate.

Last Modified: 11/23/2014
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