• Prefire (Preemptive) Management to Decrease Fire-Induced Bunchgrass Mortality and Reduce Reliance on Postfire Seeding

      Hulet, A.; Boyd, C. S.; Davies, K. W.; Svejcar, T. J. (Society for Range Management, 2015-11)
      Western rangelands are currently under severe threat from exotic annual grasses. To successfully manage rangelands that are either infested with or susceptible to exotic annual grasses, we must focus on increasing resilience to disturbance and resistance to exotic annual grass invasion. Here, we present a fuel-based model and research framework for Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle & Young) rangelands that focuses on increasing resilience to fire and resistance to exotic annual grasses through the maintenance of perennial bunchgrasses. By maintaining perennial bunchgrass, exotic annual grasses have limited resources, thus decreasing the invasibility of the site. In order for the fuel-based model to be effective in guiding land management practices, research that evaluates the interactions between biotic and abiotic factors that influence fire-induced bunchgrass mortality is needed. Hence, we propose a research framework to identify and fill potential gaps in current scientific knowledge. We also suggest potential research objectives that are necessary to make informed management decisions before wildfire, with a goal to ultimately decreasing our reliance on marginally successful postfire restoration practices through preemptive management strategies. © Published by Elsevier Inc. On behalf of Society for Range Management.
    • Behavioral Responses at Distribution Extremes: How Artificial Surface Water Can Affect Quail Movement Patterns

      Tanner, E. P.; Elmore, R. D.; Fuhlendorf, S. D.; Davis, C. A.; Thacker, E. T.; Dahlgren, D. K. (Society for Range Management, 2015-11)
      Supplementing wildlife populations with resources during times of limitation has been suggested for many species. The focus of our study was to determine responses of northern bobwhite (Colinus virginianus; Linnaeus) and scaled quail (Callipepla squamata; Vigors) to artificial surface-water sources in semiarid rangelands. From 2012-2014, we monitored quail populations via radio telemetry at Beaver River Wildlife Management Area, Beaver County, Oklahoma. We used cumulative distribution functions and resource utilization functions (RUFs) to determine behavioral responses of quail to water sources. We also used Program MARK to determine if water sources had any effect on quail vital rates. Our results indicated that both northern bobwhite and scaled quail exhibited behavioral responses to the presence of surface-water sources. Northern bobwhite selected for areas < 700 m and < 650 m from water sources during the breeding and nonbreeding season, respectively. However, the nonbreeding season response was weak ( =-0.06, SE = < 0.01), and the breeding season ( = 0.01, SE = 0.02) response was nonsignificant on the basis of RUFs. Scaled quail selected for areas < 650 m and < 250 m from water sources during the breeding and nonbreeding season, respectively. The breeding season RUF ( =-0.31, SE = 0.07) indicated a stronger response for scaled quail than bobwhite. Conversely, there was no direct effect of surface water on quail vital rates or nest success during the course of our study. Although water may affect behavioral patterns of quail, we found no evidence that it affects quail survival or nest success for these two species. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Managing Mixed-Grass Prairies for Songbirds Using Variable Cattle Stocking Rates

      Sliwinski, M. S.; Koper, N. (Society for Range Management, 2015-11)
      Most remaining grasslands are used for livestock grazing; stocking rates could be managed to help stop declining songbird populations. We examined the effects of stocking rates on grassland songbirds in northern mixed-grass prairies using a beyond-Before-After-Control-Impact manipulative experiment in Canada's Grasslands National Park and adjacent community pastures. The study area consisted of nine 300-ha pastures grazed at a range of stocking rates starting in 2008. We conducted songbird surveys at six upland plots in each pasture from 2006-2010 and measured vegetation structure within each plot from 2008-2010 (n = 54). We evaluated the effects of stocking rates on habitat structure and songbird abundance using linear and generalized linear mixed models. Baird's sparrow (Ammodramus bairdii) relative abundance declined with increasing stocking rates. Chestnut-collared longspur (Calcarius ornatus) relative abundance increased only at higher stocking rates, indicating a possible threshold effect. Savannah sparrow (Passerculus sandwichensis) relative abundance decreased with stocking rates above 0.4 AUM after a year of grazing. Sprague's pipit (Anthus spragueii) relative abundance declined with grazing, but the effect was weak and only significant in 1 year. Western meadowlark (Sturnella neglecta) abundance was unaffected by grazing. Stocking rates may be used to benefit grassland songbirds and may alter avian communities after as little as 1 month of livestock grazing. Applying a range of stocking rates regionally may provide habitat for many species. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Long-Term Effects of Phosphorus on Dynamics of an Overseeded Natural Grassland in Brazil

      Oliveira, L. B.; Soares, E. M.; Jochims, F.; Tiecher, T.; Marques, A. R.; Kuinchtner, B. C.; Rheinheimer, D. S.; De, Quadros, F. L. F. (Society for Range Management, 2015-11)
      Fertilization can affect vegetation dynamics and natural grassland diversity. This study evaluated the vegetation dynamics of a natural grassland 16 years after the initial fertilization, discussing the long-term effects of addition of triple superphosphate (TP) or Gafsa rock phosphate (RP) sources, as well as the effect of exotic species introduction on the inter seasonal dynamic of floristic composition. Phosphate (P) was applied in 1997, 1998, 2002, 2010, and 2012 at the quantities of 78.6, 39.3, 43.7, 43.7 and 43.7 kg·ha-1, respectively, totaling 249 kg·ha-1 P. Total herbage mass production (THM) with RP (13 485 kg·ha-1) and TP applications (14 668 kg·ha-1) was higher than in the Control (11 291 kg·ha-1). There was a higher warm tussock perennial grasses C4 contribution on herbage mass (HM) during the summer season (1 106 kg·ha-1), whereas it was similar between treatments. In summer, the warm-season prostrate perennial grasses C4 group contribution for HM was on average 48% higher when RP was used (1 590 kg·ha-1) in relation to the other treatments. The HM contribution from the cool season annual grasses C3 group (CAG) in the total HM, over spring 2012, winter and spring 2013 in TP treatment, was 17% higher than the other treatments. The changes in the seasonal botanical composition dynamics mainly by inducing modifications in the proportion of Paspalum notatum A. H. Liogier ex Flüggé on RP treatment and Paspalum urvillei Steud. and Lolium multiflorum Lam. on TP treatment. However, no significant effects were observed in species richness, which ranged from 19-24 species among growth seasons. In the same way, the Shannon Diversity Index and Pielou Equitability Index were not modified by historical P sources. These results indicate that phosphorus fertilization has lower effects on natural grasslands diversity and could be used as a tool with important implications for livestock. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • A Temporal Analysis of Elephant-Induced Thicket Degradation in Addo Elephant National Park, Eastern Cape, South Africa

      Kakembo, V.; Smith, J.; Kerley, G. (Society for Range Management, 2015-11)
      Elephant-induced thicket degradation in the Addo Elephant National Park (AENP), Eastern Cape, South Africa, was assessed during 1973 and 2010 using multitemporal satellite imagery. Changes in the thicket condition, in relation to the AENP expansion, were analyzed using the Normalized Difference Vegetation Index, postclassification, and landscape metrics. The change detection of land-cover classes was analyzed by postclassification. Landscape-spatial metrics were used in order to gain an understanding of vegetation-fragmentation trends. Temporal changes in vegetation gradients in relation to water points and thicket conditions within the botanical reserves were also assessed. The thicket condition was noted to have deteriorated, as the AENP had expanded. An expansion of degraded vegetation away from the water points was identified during the study period. The thicket condition in botanical reserve 1 had fluctuated, whereas it remained constant in reserves 2 and 3. Landscape spatial-metric analyses revealed evidence of increased vegetation fragmentation, as new areas of the AENP had been opened for elephant activity. A progressive decline in intact thicket and an increase in degraded thicket were observed. Remote-sensing techniques can assist with thicket-clump restoration by applying "target monitoring" for the timeous identification of potential-degradation hotspots. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Ranch Owner Perceptions and Planned Actions in Response to a Proposed Endangered Species Act Listing

      Knapp, C. N.; Stuart III, Chapin, F.; Cochran, J. O. (Society for Range Management, 2015-11)
      The Gunnison sage-grouse (GUSG) is an iconic species recently proposed for protection under the Endangered Species Act (ESA). In Colorado's Upper Gunnison River Basin, ranchers own the majority of water rights and productive river bottoms as well as approximately 30% of the most important GUSG habitat. This project used mixed-methods interviews with 41 ranch owners to document how ranchers perceive the proposed ESA listing and how they plan to respond to a listing decision. Results show that ranchers support on-the-ground GUSG conservation but are concerned about listing implications. Ranchers are most concerned about their ability to manage public and private lands productively and continue permitted grazing on public lands. If the species is listed, landowners plan to decrease participation in conservation strategies, including plans to adopt conservation easements, participation in conservation programs, and willingness to allow access to private lands for GUSG monitoring. Land-owners also express plans for increased sales of land and water, which could have negative consequences for GUSG habitat. This research suggests that changes in the application of the ESA could lead to beneficial conservation outcomes. These changes include increased transparency, ability to exclude stable populations from listing under the ESA, and commitment to work with local bodies if the species is listed. This project demonstrates the importance of qualitative research for understanding the indirect and unintended effects of species protections in an increasingly interconnected world. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Evaluating Winter/Spring Seeding of a Native Perennial Bunchgrass in the Sagebrush Steppe

      Boyd, C. S.; Lemos, J. A. (Society for Range Management, 2015-11)
      Sagebrush (Artemisia tridentata Nutt.) plant communities in the Great Basin region are being severely impacted by increasingly frequent wildfires in association with the expansion of exotic annual grasses. Maintaining native perennial bunchgrasses is key to controlling annual grass expansion, but postfire restoration of these species has proven difficult with traditional fall drill-seeding. We investigated the potential for winter/spring seeding bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) in southeast Oregon. In 2011-2013, 500 seeds were planted in fall, or weekly from March through early May in 1·m-2 plots using a randomized block design with 5 replications. Germination was estimated using buried bags, and emergent seedlings were counted weekly from March to June. Germination and emergence varied strongly between years and by within-year timing of planting. With adequate precipitation, percent germination was high (up to 100%) regardless of timing of planting and emergence density decreased (P ≤ 0.05) with advancing winter/spring planting date in drier years. Emergence density was high (approaching 300 plants/m-2) with adequate precipitation but varied strongly across planting weeks for winter/spring plantings. Percent survival of emergent seedlings to harvest (July) was approximately 25-50% lower (P ≤ 0.05) for fall-planted seeds in all years; survival of winter/spring seedlings was 80-100% with no discernable pattern between planting weeks. Our results indicate that winter/spring seeding of perennial bunchgrasses is biologically feasible in years with adequate precipitation but fall seeding was more consistently successful. Additional research is needed to determine environmental factors driving within-year variation in demographics for winter/spring planted seeds. © Published by Elsevier Inc. On behalf of Society for Range Management.
    • Germination and Seedling Emergence of Three Semiarid Western North American Legumes

      Bushman, B. S.; Johnson, D. A.; Connors, K. J.; Jones, T. A. (Society for Range Management, 2015-11)
      Few seed sources of North American forbs are available for revegetation/restoration of degraded western rangelands adapted to annual precipitation zones less than 300 mm, and those that are available are mainly wildland collected. The amount of time and resources necessary to make wildland collections in quantity results in high seed prices and variable seed quality, such that forbs have been under-represented in rangeland seeding mixes. We have previously identified western prairie clover (Dalea ornata Douglas ex Hook.), Searls' prairie clover (Dalea searlsiae A. Gray), and basalt milkvetch (Astragalus filipes Torr. ex A. Gray) as native species adapted to low precipitation zones in the western United States for which field-grown seed production would potentially reduce seed costs and increase availability. A series of glasshouse experiments were conducted to determine the effects of scarification, planting depth, and soil composition on germination and seedling emergence of these species. All three species produce hard seeds, and scarification was necessary to increase germination and seedling emergence. Compared with a 6-mm planting depth, a planting depth of 19 mm retarded the rate of emergence for all species but only reduced the total seedling emergence for basalt milkvetch. With seed scarification in sandy soils, prairie clover seedling emergence exceeded 80% while basalt milkvetch was less than 10%. With seed scarification in soils with higher clay content, prairie clover total seedling emergence reduced to 58-70% while basalt milkvetch increased to approximately 30%. Along with enhancing stand establishment in seed production fields, these data will assist land managers in planning for optimal establishment of these species in rangeland revegetation/restoration projects. © Published by Elsevier Inc. On behalf of Society for Range Management.
    • Contrasting Mechanisms of Recovery from Defoliation in Two Intermountain-Native Bunchgrasses

      Mukherjee, J. R.; Jones, T. A.; Adler, P. B.; Monaco, T. A. (Society for Range Management, 2015-11)
      Grazing tolerance of dominant native species may determine the fate of rangeland ecosystems, and using native plant populations with good grazing tolerance in restoration seedings may improve ecosystem resilience, especially when domestic herbivores are present. We examined interspecific and intraspecific differences in shoot biomass and defoliation tolerance for two semiarid, perennial cool-season bunchgrasses native to the Intermountain West, USA, Pseudoroegneria spicata and Elymus wawawaiensis, on the basis of four functional traits (specific leaf area [SLA], plant basal area, tiller number, and tiller mass). We applied two treatments, control and boot-defoliation, where the latter included defoliation at the early-reproductive ("boot") stage, the phenological stage most vulnerable to herbivory, while the control treatment did not. We tested two contrasting hypotheses (i.e., that boot-defoliation tolerance is increased through either increases in SLA or through more favorable tiller demography). For shoot biomass, both grasses were less productive under the boot-defoliation treatment than for the control, but E. wawawaiensis displayed higher boot-defoliation tolerance than P. spicata. Interpopulation variation occurred in all four functional traits for P. spicata, but there were no such variation for E. wawawaiensis. The tiller demography hypothesis better explained boot-defoliation tolerance in both species, and neither SLA nor plant basal area was correlated with shoot biomass for either treatment. Of the traits measured, high tiller number served as the primary mechanism for shoot biomass and boot-defoliation tolerance in P. spicata, while tiller number and tiller mass were both important predictors of both shoot biomass and boot-defoliation tolerance. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.
    • Simulating Carbon Dioxide Effects on Range Plant Growth and Water Use with GPFARM-Range Model

      Qi, Z.; Morgan, J. A.; McMaster, G. S.; Ahuja, L. R.; Derner, J. D. (Society for Range Management, 2015-09)
      Steadily 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 &gt; 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 Hillslopes

      Pierson, F. B.; Williams, C. J.; Kormos, P. R.; Al-Hamdan, O. Z.; Hardegree, S. P.; Clark, P. E. (Society for Range Management, 2015-09)
      Tree 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 Ethiopia

      Kebede, A. T.; Coppock, D. L. (Society for Range Management, 2015-09)
      Prosopis 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.
    • Sustaining Working Rangelands: Insights from Rancher Decision Making

      Roche, L. M.; Schohr, T. K.; Derner, J. D.; Lubell, M. N.; Cutts, B. B.; Kachergis, E.; Eviner, V. T.; Tate, K. W. (Society for Range Management, 2015-09)
      Grazed 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.
    • Informal Rangeland Monitoring and Its Importance to Conservation in a U.S. Ranching Community

      Woods, S. R.; Ruyle, G. B. (Society for Range Management, 2015-09)
      Effective 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 Wyoming

      Dahlgren, D. K.; Larsen, R. T.; Danvir, R.; Wilson, G.; Thacker, E. T.; Black, T. A.; Naugle, D. E.; Connelly, J. W.; Messmer, T. A. (Society for Range Management, 2015-09)
      Conservation 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 Sources

      Brabec, M. M.; Germino, M. J.; Shinneman, D. J.; Pilliod, D. S.; McIlroy, S. K.; Arkle, R. S. (Society for Range Management, 2015-09)
      The 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.
    • Demographic Changes Drive Woody Plant Cover Trends - An Example from the Great Plains

      Berg, M. D.; Sorice, M. G.; Wilcox, B. P.; Angerer, J. P.; Rhodes, E. C.; Fox, W. E. (Society for Range Management, 2015-07)
      Woody plant encroachment - the conversion of grasslands to woodlands - continues to transform rangelands worldwide, yet its causes and consequences remain poorly understood. Despite this being a coupled human-ecological phenomenon, research to date has tended toward ecological aspects of the issue. In this paper, we provide new insight into the long-term relationships between human demographics and woody plant cover at the landscape scale. We used time-series aerial imagery and historical census data to quantify changes in population, land ownership patterns, and woody cover between 1937 and 2012 in three different settings in central Texas, USA. Woody cover closely paralleled population in a semi-urban watershed (R2 = 0.81) and two separate clusters of rural watersheds (R2 = 0.88 and 0.93), despite exhibiting very different directional trends over time in each setting. Woody cover also closely tracked average farm size in each rural watershed cluster (R2 = 0.57 and 0.90). These results highlight a tight coupling between demographic trends and the extent of woody plant cover. Such human factors may explain a great deal of woody plant cover patterns in other global rangeland systems with similar historical contexts and serve as a predictive proxy of landscape trends. Accordingly, policy recommendations should consider these demographic factors, and future woody plant encroachment research should explicitly include human dimensions. © 2015 Society for Range Management. Published by Elsevier Inc. All rights reserved.