Land managers must consider a range of factors, including soil and microclimate, and pre-treatment condition when determining which treatments to apply, and where to apply them for best recovery.
Lawrence, KS (PRWEB) October 09, 2014
Rangeland Ecology & Management – The best intentions may not always be the right ones. Prescribed burns, mowing, and herbicides are important tools for managing healthy rangelands, but these activities also greatly change the environment. Only a long view can reveal whether intent and results align.
In an article in the current issue of the journal Rangeland Ecology & Management, the authors describe just such a long view: the Sagebrush Steppe Treatment Evaluation Project (SageSTEP), which focuses on ecosystems in mountain region of the western United States. The authors highlight the initial effects of the project, which began in 2005, and describe results of restoration efforts.
SageSTEP was designed to offer solutions to changing sagebrush steppes in intermountain west. Suppressing fires, grazing livestock, and invasive annual grasses and conifers has decreased the quality of these ecosystems. Cheatgrass and other invasive annuals have overwhelmed native bunchgrasses at lower elevations, and wildfire frequency has increased despite control efforts; woodlands have overrun to higher elevation areas, and wildfire severity has increased as a result.
At 21 sites in five states, two experiments were conducted as part of SageSTEP. One experiment focused on cheatgrass invasion. At seven lower-elevation sites, one plot of land was left alone as a control and three others were intentionally burned, mowed, or sprayed with herbicides. The second experiment focused on piñon and juniper expansion at 14 higher-elevation sites. Again, a control plot in each site was compared with plots from which the trees were removed by either prescribed fire or mechanical methods. For both experiments, a range of variables were then followed, examined, and analyzed over several years.
The project revealed that sagebrush steppe resilience, or its ability to recover from environmental stresses such as prescribed burns, was better in cool, moist areas than in warm, dry ones. It found that resistance, or ability to withstand stresses such as annual invasive plants, followed a generally similar climate pattern. Intensive grazing appeared to decrease both resistance and resilience, as did erosion, especially for relatively warm sites with sandy soils.
In all study plots, woody vegetation was removed, reduced, or redistributed, which generally encouraged the herbaceous understory to grow. The experiments showed that the more perennial bunchgrass, the greater a site’s ability to withstand and recover from efforts to remove trees and invasive competitors. Although prescribed fire is the most cost-effective tool, any reduction in woody vegetation increased soil water, herbaceous understory growth, and butterfly populations.
The authors of the article concluded that by focusing on native perennial grass recovery, land managers have the best chance of improving sagebrush steppe systems. Yet they must consider a range of factors, including soil and microclimate, and pre-treatment condition, when determining which treatments to apply, and where to apply them for best recovery. Necessary trade-offs make a whole-system view and a consistent, long-term monitoring and evaluating process crucial to preventing woodland and cheatgrass from taking over sagebrush steppe systems.
Full text of the article “A synopsis of short-term response to alternative restoration treatments in sagebrush-steppe: The SageSTEP project,” Rangeland Ecology & Management, Vol. 67, No. 5, 2014, is now available.
About Rangeland Ecology & Management
Rangeland Ecology & Management is a peer-reviewed journal of the Society for Range Management that is published six times a year. The journal provides a forum for the presentation and discussion of research information, concepts, and philosophies pertaining to the function, management, and sustainable use of global rangeland resources. The journal is available online at http://www.srmjournals.org. To learn more about the society, please visit http://www.rangelands.org.