Rangeland Ecology & Management, Volume 68, Number 5 (September 2015)
ABOUT THE COLLECTIONS
Welcome to the Rangeland Ecology & Management archives. The journal Rangeland Ecology & Management (RE&M; v58, 2005-present) is the successor to the Journal of Range Management (JRM; v. 1-57, 1948-2004.) The archives provide public access, in a "rolling window" agreement with the Society for Range Management, to both titles (JRM and RE&M), from v.1 up to five years from the present year.
The most recent years of RE&M are available through membership in the Society for Range Management (SRM). Membership in SRM is a means to access current information and dialogue on rangeland management.
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Print ISSN: 0022-409x
Online ISSN: 1550-7424
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Sustaining Working Rangelands: Insights from Rancher Decision MakingGrazed rangeland ecosystems encompass diverse global land resources and are complex social-ecological systems from which society demands both goods (e.g., livestock and forage production) and services (e.g., abundant and high-quality water). Including the ranching community's perceptions, knowledge, and decision-making is essential to advancing the ongoing dialogue to define sustainable working rangelands. We surveyed 507 (33% response rate) California ranchers to gain insight into key factors shaping their decision-making, perspectives on effective management practices and ranching information sources, as well as their concerns. First, we found that variation in ranch structure, management goals, and decision making across California's ranching operations aligns with the call from sustainability science to maintain flexibility at multiple scales to support the suite of economic and ecological services they can provide. The diversity in ranching operations highlights why single-policy and management "panaceas" often fail. Second, the information resources ranchers rely on suggest that sustaining working rangelands will require collaborative, trust-based partnerships focused on achieving both economic and ecological goals. Third, ranchers perceive environmental regulations and government policies-rather than environmental drivers-as the major threats to the future of their operations. © 2015 Society for Range Management.
Simulating Carbon Dioxide Effects on Range Plant Growth and Water Use with GPFARM-Range ModelSteadily rising carbon dioxide (CO2) in the Earth's atmosphere has the potential to increase plant biomass production and reduce plant transpiration in semiarid rangelands. Incorporating results from field CO2-enrichment experiments into process-based simulation models enhances our ability to project climate change impacts on these rangelands. In this study, we added algorithms for computing changes in plant biomass growth and stomatal resistance under elevated [CO2] to the GPFARM-Range (Great Plains Framework for Agricultural Resource Management in Rangelands) model, a newly developed stand-alone software package for rangeland management. The GPFARM-Range model was tested against 5 yr (1997-2001) of soil water and plant biomass data from CO2-enrichment (720 ppm) field experiments conducted in shortgrass steppe in northern Colorado. Simulated results for both peak standing crop biomass and soil water for both ambient and elevated [CO2] treatments had a percent bias within ± 10%, Nash-Sutcliffe efficiency ≥ 0.5, and index of agreement > 0.70. The model also captured the observed trend of increased C3 grass biomass and reduced plant transpiration under elevated [CO2]. The model was used to evaluate the separate effectiveness of elevated [CO2] on plant growth rate (C3 grasses only) and stomatal resistance (both C3 and C4 grasses). Two separate simulations showed that increased growth rate and stomatal resistance due to elevated [CO2] enhanced total plant biomass gain (C3 + C4) by 22% and 17%, respectively. The results indicate the algorithms used to simulate the impacts of elevated [CO2] on range plant growth and water use are reliable and can be used to evaluate rangeland production for predicted increases in [CO2], However, further studies are necessary because the reduction in plant transpiration under elevated [CO2] was underestimated, and increase in nitrogen use efficiency due to elevated [CO2] is not included. © 2015 Society for Range Management.
Short-Term Impacts of Tree Removal on Runoff and Erosion From Pinyon- and Juniper-Dominated Sagebrush HillslopesTree removal is often applied to woodland-encroached rangelands to restore vegetation and improve hydrologic function, but knowledge is limited regarding effects of tree removal on hydrologic response. This study used artificial rainfall and overland flow experiments (9-13 m2) and measures of vegetation and ground cover to investigate short-term (1-2 yr) responses to tree removal at two woodland-encroached sites. Plots were located under trees (tree zone) and in the intercanopy (shrub-interspace zone, 75% of area). Before tree removal, vegetation and ground cover were degraded and intercanopy runoff and erosion rates were high. Cutting and placing trees into the intercanopy did not significantly affect vegetation, ground cover, runoff, or erosion 1 yr posttreatment. Whole-tree mastication as applied in this study did not redistribute tree mulch within the intercanopy, but the treatment did result in enhanced herbaceous cover and hydrologic function in the intercanopy. Fire removal of litter and herbaceous cover increased tree-zone runoff and erosion under high-intensity rainfall by 4- and 30-fold at one site but had minimal impact at the other site. Site response differences were attributed to variability in burn conditions and site-specific erodibility. Burning had minimal impact on shrub-interspace runoff and erosion from applied high-intensity rainfall. However, 1 yr postfire, erosion from concentrated overland flow experiments was 2- to 13-fold greater on burned than unburned tree-zone and shrub-interspace plots and erosion for burned tree zones was 3-fold greater for the more erodible site. Two yr postfire, overland flow erosion remained higher for burned versus unburned tree zones, but enhanced intercanopy herbaceous cover reduced erosion from shrub-interspace zones. The net impact of burning included an initial increase in erosion risk, particularly for tree zones, followed by enhanced herbaceous cover and improved hydrologic function within the intercanopy. The overall results suggest that erosion from late-succession woodlands is reduced primarily through recruitment of intercanopy herbaceous vegetation and ground cover. © 2015 Published by Elsevier Inc.
Livestock-Mediated Dispersal of Prosopis juliflora Imperils Grasslands and the Endangered Grevy's Zebra in Northeastern EthiopiaProsopis juliflora (Sw.) DC is a woody plant from the Americas that has dispersed worldwide via human intervention. Typically introduced with good intentions, Prosopis often proliferates and degrades native ecosystems. Prosopis first appeared in the Allideghi Wildlife Reserve (AWR) of northeastern Ethiopia in 1997. In 2005-2006 we determined: (1) patterns of Prosopis dispersal and establishment using global-positioning system mapping and seed-bank assessments; (2) impacts of Prosopis on cover composition and species richness of grassland vegetation using transects at replicated Prosopis stands that varied by tree size; and (3) attitudes of local people toward Prosopis using focus groups and interviews. Prosopis seeds first arrived in the AWR after pastoral livestock consumed seedpods along the Awash River, some 50 km away. Seeds have been deposited in corrals at recently established pastoral settlements within the AWR, and saplings now sprout along livestock trails. Prosopis has also colonized the AWR core grassland area, a vital habitat for wild grazers. Compared with sites lacking Prosopis, the largest class of Prosopis significantly reduced understory basal cover for perennial grasses from 68% to 2%, increased soil surface exposure from 30% to 80%, and lowered the number of grass species from seven to two. Attitudes of pastoralists toward Prosopis have become more negative over time. Local communities use Prosopis via limited charcoal production with some grinding of the seedpods for livestock feed. Infested sites are cleared by hand, but control has been ineffective. Because pastoral livestock are the main vectors for Prosopis seed dispersal and facilitate establishment, they will help transform the core of the AWR ecosystem from open grassland to denuded Prosopis woodland. While this bodes ill for grazing animals in general, it has particularly negative implications for the survival of an isolated population of an endangered, grass-dependent species-Grevy's zebra (Equus grevyi). © 2015 Society for Range Management.
Informal Rangeland Monitoring and Its Importance to Conservation in a U.S. Ranching CommunityEffective natural resource management relies on accurate and timely information on the natural environment, which may be obtained by formal ("scientific") or informal ("local" or "traditional") methods. Formal monitoring methods are well documented and widely accepted among the rangeland science community, yet adoption by U.S. ranchers is inconsistent. In contrast, informal monitoring appears to be widely used by ranchers, but its practice and importance have rarely been documented or assessed. By interviewing ranchers and government agency personnel, we evaluated informal monitoring in and around the Altar Valley, Arizona, United States. Informal monitoring techniques included qualitative visual appraisals of forage quantity, indicator species and erosion, and incorporated local environmental history. The environmental knowledge embedded in informal monitoring was generally compatible with natural science. Informal monitoring was conducted continuously throughout the year and provided near real-time assessments that integrated observations of most land in individual pastures and ranches. In contrast, formal monitoring was generally performed only once per year, in a limited number of areas and with a delay of a few months between observation and completion of analysis. Thus informal monitoring had higher spatial coverage and temporal resolution and provided assessments faster than formal monitoring. Consequently, ranchers generally considered informal monitoring to be more relevant than formal monitoring to formulating yearly grazing plans and responding rapidly to unpredictable changes in the natural environment. Ranchers incorporated informal monitoring into assessments of rangeland trends and outcomes of conservation measures and thereby into choices of grazing system and planning of brush management and erosion control. Thus informal monitoring was foundational to long-term conservation, annual rangeland management planning, and adaptive natural resource management on subyearly timescales. If informal monitoring is of comparable utility in other rural communities, it would appear advantageous to document and evaluate informal approaches and to incorporate them into formal conservation planning. © 2015 The Authors.
Greater Sage-Grouse and Range Management: Insights from a 25-Year Case Study in Utah and WyomingConservation of sagebrush (Artemisia spp.) systems is one of the most difficult and pressing concerns in western North America. Sagebrush obligates, such as greater sage-grouse (Centrocercus urophasianus; hereafter sagegrouse), have experienced population declines as sagebrush systems have degraded. Science-based management is crucial to improve certainty in range management practices. Although large-scale implementation of management regimens within an experimental design is difficult, long-term case studies provide opportunities to improve learning and develop and refine hypotheses. We used 25 years of data across three large landscapes in northern Utah and southwestern Wyoming to assess sage-grouse population change and corresponding land management differences in a case study design. Sage-grouse lek counts at our Deseret Land and Livestock (DLL) study site increased relative to surrounding populations in correspondence with the implementation of small-acreage sagebrush treatments designed to reduce shrub cover and increase herbaceous understory within a prescriptive grazing management framework. The higher lek counts were sustained for nearly 15 years. However, with continued sagebrush treatments and the onset of adverse winter conditions, DLL lek counts declined to levels consistent with surrounding areas. During summer, DLL sage-grouse broods used plots of small, treated sagebrush mosaics more than untreated reference sites. We hypothesize that sagebrush treatments on DLL increased availability of grasses and forbs to sagegrouse, similar to other studies, but that cumulative annual reductions in sagebrush may have reduced availability of sagebrush cover for sage-grouse seasonal needs at DLL, especially when extreme winter weather occurred. © 2015 The Authors.
Challenges of Establishing Big Sagebrush (Artemisia tridentata) in Rangeland Restoration: Effects of Herbicide, Mowing, Whole-Community Seeding, and Sagebrush Seed SourcesThe loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of other native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing the site before planting seedlings led to greater initial survival probabilities for sagebrush outplants, except where seeding also occurred, and these effects were related to corresponding changes in bare soil exposure. Initial survival probabilities were > 30% greater for the local population of big sagebrush relative to populations imported to the site from typical seed transfer distances of ∼320-800 km. Overcoming the high first-year mortality of outplanted or seeded sagebrush is one of the most challenging aspects of postfire restoration and rehabilitation, and further evaluation of the impacts of herb treatments and sagebrush seed sources across different site types and years is needed. © 2015 Published by Elsevier Inc.