The presence of gray wolves (Canis lupus) can directly and indirectly affect beef cattle (Bos taurus) production on rangelands of the Northern Rocky Mountains. While fairly extensive knowledge exists for the direct effects of wolf predation threat (e.g., cattle death and injury losses, elevated stress), our understanding of wolf-caused changes in cattle behavior and the associated cascade of potential indirect effects on cattle resource selection, diet quality, activity budgets, and energetic relationships is still largely in its infancy. We investigated whether wolf presence affected the daily travel distance of Global Positioning System (GPS) — collared cattle under a replicated, Impact-Control study conducted in western Idaho and northeastern Oregon during 2008 — 2012. Cattle in three Control (Oregon) study areas, where wolf presence was consistently low, traveled farther per day (13.7 ± 0.396 SE km day^-1) than those in three Impact (Idaho) study areas (11.4 ± 0.396 SE km day^-1) with moderate to high wolf presence. At Control study areas, cattle traveled farthest per day in July (13.2 ± 0.355 SE km day^-1) and were least mobile in October (11.8 ± 0.365 SE km day^-1), but daily travel distances were similar across all months for cattle in Impact study areas. This observational study provides evidence suggesting cattle in mountainous grazing areas alter their spatial behavior in response to gray wolf presence. These behavioral changes have energetic consequences that could potentially impact cattle productivity and ranch economics. Additional research into the activity budget and resource selection responses of these collared cattle is required to better understand the specific mechanisms behind these daily travel distance results.

US government agencies are adopting state and transition models (STMs) for rangeland evaluation, monitoring, and management. This research demonstrates advantages of combining STMs and ranch economic models. A dynamic optimization framework casts management decisions—stocking rates and brush control—in the context of ranch profitability over a suite of ecological sites. Markov processes characterize the likelihood of state transitions.

The ranch model shows economic interdependence of multiple ecological sites. Ecological site combinations producing the most forage are not the most economically advantageous. The state of one ecological site influences the forage value elsewhere and ultimately the intensity at which a ranch is stocked. Likewise, brush control benefits depend importantly on the state of all ecological sites.

Understanding the capture and redistribution of water within ecological sites should improve our understanding of the function of rangeland watersheds. We compare ecological site physical properties, runoff events, and precipitation event characteristics to assess the variability in hydrologic response of four ecological sites to natural rainfall events in a semiarid watershed in southeast Wyoming, United States. Ecological sites were selected on the basis of their extent of areal coverage in the watershed and their perceived importance in watershed scale hydrologic response. At each study site, four 12-m² runoff plots were installed with collection troughs to capture and quantify the rate and amount of runoff. A tension infiltrometer was used to measure effective saturated hydraulic conductivity at the point scale, and a data-logging rain gauge was installed at each site to measure rainfall. One-way analysis of variance (α = 0.05) was used to compare the hydrologic characteristics of ecological sties. Amounts and intensities of rainfall required to generate runoff, timing of overland flow, and peak runoff rates differed (P < 0.05) among sites in their current state. We found differences in effective hydraulic conductivity, 20.30 mm hr^-1 on shallow loamy site up to 50.40 mm hr^-1 on the coarse upland, and plot water storage potential, which varied from 101.8 mm on the shallow loamy site to 472.0 mm on the loamy upland site, due to differences in soil depth and porosity among sites. After normalizing runoff according to rainfall depth, we found no statistical difference (P > 0.05) in the volumes of runoff produced by different sites. The amount of runoff generated on all sites was very small, indicating high infiltration and limited ponding and overland flow. Ecological sites were shown to have different hydrologic response characteristics (i.e., timing of runoff), suggesting that they can be used to better quantify and understand the variability in hydrology in rangeland watersheds.

Although crested wheatgrass (Agropyron cristatum [L] Gaertn. & A. desertorum [Fisch. ex Link] Schult.) has been one of the most commonly seeded exotic species in the western United States, long-term successional trajectories of seeded sites are poorly characterized, especially for big sagebrush (Artemisia tridentata Nutt.) ecosystems in the Great Basin. Interpreting successional trajectories is particularly difficult because many seeded sites were actively managed with subsequent treatments to kill sagebrush and sustain high forage productivity of crested wheatgrass plants. In addition, inherent differences in climate, topography, soils, and disturbance regimes may lead to variable vegetation structure and species composition among seeded sites. To clarify variation in successional trajectories, we measured vegetation composition, plant species diversity, ground cover, and soil properties in 38 historical crested wheatgrass seedings distributed across 146 sampling sites that lacked subsequent sagebrush treatments. The multivariate dataset was analyzed using principal components analysis to identify “defining factors” that best explained variation among sites. Variation was primarily attributed to an inverse relationship between crested wheatgrass and sagebrush abundance (R² = 0.69; P < 0.0001) and their affinity for either silty or sandy soil textures, respectively, as well as a negative association between crested wheatgrass abundance and species diversity (R² = 0.67; P < 0.0001). These results do not support the assumption that crested wheatgrass seedings uniformly remain in vegetation states with low diversity and poor sagebrush reestablishment over the long term (i.e., 43 – 63 yr). We suggest that a broader interpretation of plant community dynamics is needed while avoiding generalizations of how historically seeded Wyoming big sagebrush sites will respond over time.

Utah lotus (Lotus utahensis Ottley) is a North American leguminous forb that may hold promise for rangeland revegetation in the western United States for diversifying planting mixtures, attracting pollinators, providing high-quality forage, and expanding habitats for insects needed by sage-grouse chicks. Fourteen wildland seed collections of Utah lotus originating from Nevada and Utah were assessed for genetic variation of a wide range of phenotypic traits and genetic relationships. Population structure estimates defined by 552 amplified fragment length polymorphism (AFLP) markers identified three primary subgroups within the Utah lotus collections, which corresponded to their geographic origin. Two collections of Utah lotus (LU-5 and LU-20) were among the top-performing collections for the phenotypic traits examined, including dry-matter yield, pod production, number of stems, canopy height, and persistence. No significant Pearson's correlations or canonical correlations were observed among the phenotypic traits and environmental characteristics at the collection sites. Significant correlations were detected between genetic and geographic matrices, and phenotypic and geographic distance matrices (r = 0.89, P = 0.001 and r = 0.24, P = 0.04, respectively). Condensed tannin (CT) contents of Utah lotus were between 146 and 199 g kg^-1 dry matter, which was nearly 10 times higher than CT content of birdsfoot trefoil (Lotus corniculatus L.) with 17.3 g kg^-1 dry matter. Because of our phenotypic and genotypic evaluations, one pooled germplasm source of Utah lotus comprising collections LU-5 and LU-20 could be developed for use in rangeland revegetation in the southern Great Basin and Colorado Plateau.

The shortgrass steppe (SGS) occupies the southwestern part of the Great Plains. Half of the land is cultivated, but significant areas remain under natural vegetation. Despite previous studies of the SGS carbon cycle, not all aspects have been completely addressed, including gross productivity, ecosystem respiration, and ecophysiological parameters. Our analysis of 1998 — 2007 flux tower measurements at five Bowen ratio-energy balance (BREB) and three eddy covariance (EC) sites characterized seasonal and interannual variability of gross photosynthesis and ecosystem respiration. Identification of the nonrectangular hyperbolic equation for the diurnal CO₂ exchange, with vapor pressure deficit (VPD) limitation and exponential temperature response, quantified quantum yield α, photosynthetic capacity A_max, and respiration rate r_d with variation ranges (19 < α < 51 mmol mol^-1, 0.48 < A_max < 2.1 mg CO₂ m^-2 s^-1, 0.15 < r_d < 0.49 mg CO₂ m^-2 s^-1). Gross photosynthesis varied from 1 100 to 2 700 g CO₂ m^-2 yr^-1, respiration from 900 to 3,000 g CO₂ m^-2 yr^-1, and net ecosystem production from — 900 to 700 g CO₂ m^-2 yr^-1, indicating that SGS may switch from a sink to a source depending on weather. Comparison of the 2004–2006 measurements at two BREB and two parallel EC flux towers located at comparable SGS sites showed moderately higher photosynthesis, lower respiration, and higher net production at the BREB than EC sites. However, the difference was not related only to methodologies, as the normalized difference vegetation index at the BREB sites was higher than at the EC sites. Overall magnitudes and seasonal patterns at the BREB and the EC sites during the 3-yr period were similar, with trajectories within the ± 1.5 standard deviation around the mean of the four sites and mostly reflecting the effects of meteorology.

The natural Andean vegetation environment is the most important resource available to local pastoralist economies. Knowledge of its attributes is vital in assessing ecosystem properties and improves management decision making. However, there is a lack of research on models that estimate species and life-form biomass for the Puna. We developed a series of models that facilitated the estimation of biomass while avoiding the direct harvesting of the most representative Puna steppe plant species in Jujuy, Argentina. The models thus developed are useful tools in the evaluation of changes in ecosystem dynamics through time and space. Allometric equations were developed for the dominant shrubs (Baccharis boliviensis, Fabiana densa, Parastrephia quadrangularis, Tetraglochin cristatum, Ocyroe armata, and Adesmia sp.) and tussock grasses (Jarava ichu, Festuca crysophylla, and Cenchrus chilense). A field record of the maximum diameter, perpendicular diameter, and height of each plant; number of individuals per plot; and tussock grasses and shrub cover across all vegetation communities was undertaken. Linear regressions including plant measures demonstrated a good fit (R² > 0.7, P < 0.001) to the biomass for individual plants and surface area. The predictive equations developed allow for the rapid and accurate estimation of shrub and tussock biomass. This is essential to monitor the effects of grazing for impact assessment of the different management practices and vegetation dynamics.

Spectral indices derived from satellite observations, such as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), are widely used for grassland monitoring and management around the globe. In this study we contrasted performance of NDVI and EVI metrics obtained from Aqua and Terra, the two satellite platforms carrying the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, for estimating grassland cover measured at ground level on ninety-two 1×1 km blocks distributed from semidesert to high montane grasslands in the Sailugem Range of western Mongolia, where overgrazing and overstocking of domestic livestock are concerns for pastureland management. We also explored utility of late spring (May) vegetation indices for forecasting vegetation cover at the peak of the growing season (July). Vegetation indices developed using MODIS 1-km monthly data (MOD13A3 and MYD13A3) were strongly related to on-the-ground field estimates of the percentage of vegetation cover in July (74–85% variation explained), with second-order polynomial regressions demonstrating better fit to the data than first-order regressions, Aqua vegetation indices (VIs) explaining slightly more variance than Terra's VIs, and NDVI performing comparably to EVI for both Aqua and Terra. Both Aqua and Terra VIs for May were highly predictive of July vegetation cover (R² = 0.80–0.84). We conclude that monthly MODIS NDVI and EVI datasets can be useful for rangeland managers in western Mongolia to monitor and predict summer pasture conditions at the regional level, where sciencebased guidance on grazing policy and practices is much needed.

The extent and heterogeneity of rangelands in the state of Nevada (United States) pose a challenging situation for land managers when determining stocking levels for livestock grazing. Overutilization can cause lasting environmental damage, while underutilization can create unnecessary economic hardship for livestock operators. An improved ability to forecast vegetation stress later in the growing season would allow resource managers to better manage the tradeoffs between ecological and economic concerns. This research maps how well growing season conditions for vegetation within grazing allotments of Nevada can be predicted at different times of the year by analyzing 15 yr of enhanced vegetation index (EVI) data from the Moderate Resolution Imaging Spectroradiometer sensor, cumulative monthly precipitation, and the Palmer drought severity index. Land cover classes within the grazing allotments that are not relevant to grazing were removed from the analysis, as well as areas that showed > 50% change in EVI since these likely represented transitions or disturbances that were not related to interannual climate variability. The datasets were gridded at spatial resolutions from 4 to 72 km, and the correspondence between image and meteorological datasets was found to improve as measurements were averaged over larger areas. A 16-km sampling grid was judged to provide the best balance between predictive ability and spatial precision. The average R² of regressions between the vegetation index and meteorological variables within each of the 16-km grid cells was 0.69. For most of Nevada, the ability to predict vegetation conditions for the entire growing season (February–September) generally peaks by the end of May. However, results vary by region, with the northeast particularly benefiting from late-season data. Regressions were performed with and without very wet years, and the ability to make early predictions is better when including wet years than in dry to typical conditions.

Phenotypic plasticity enables plants to cope with changes in their environment. Plasticity in a population of Leymus chinensis, a common grass species in arid and semiarid temperate grasslands of northern China, was determined in a natural grassland grazed by large domestic herbivores. We measured shoot and bud characteristics monthly along a grazing intensity gradient indicated by distance from the village gate during two growing seasons. In addition, some plants along the gradient were removed to a common transplant garden and their growth was compared. Leaf characteristics (leaf angle, leaf length, and leaf number), growth form (tiller height and tiller clusters), bud proliferation, and plant fitness differed significantly in situ along the gradient. The expression of plasticity was grazing intensity dependent: the greatest increase in tiller density, tiller cluster, and bud number occurred at a moderate grazing intensity (2.5 km from the village gate). In the transplant garden, no evidence was found for distinct populations of L. chinensis within the grassland. Leaf characteristics, tiller growth form, and bud demography of tillers not grazed showed phenotypic plasticity in response to grazing of neighbor shoots because clonal reproduction is the main breeding system for this species in grazed natural grassland and defoliation of neighbor shoots is likely to affect the physiology and morphology of tillers that are not grazed. The observed overcompensation in vegetative reproduction may aid future survival and growth and could be achieved in a prudent grazing system designed to take into account the needs of this dominant grass in semiarid temperate steppes.

Exotic annual grasses have invaded millions of hectares of sagebrush (Artemisia L.) steppe in the Great Basin region and degraded wildlife habitat, reduced forage production, and promoted increasingly frequent wildfires. Revegetation after control of exotic annual grasses is needed to restore ecosystem services and break the annual grass-fire cycle. The ability of different common revegetation species and combinations of species to limit reinvasion of annual grasses is relatively unknown. We evaluated five species/combinations of perennial native and introduced bunchgrass and shrub species planted as seedlings after exotic annual grass control at two sites in southeast Oregon. To evaluate resistance to reinvasion, exotic annual grasses were seeded into all treatment plots in the fall two growing seasons after planting. Vegetation characteristics were measured in the third and fourth years after annual grass seeding. Exotic annual grass cover and density were greatly reduced in all treatments where perennial seedlings were planted compared with the control (no seedlings planted). Treatments including crested wheatgrass (Agropyron desertorum [Fisch. Ex Link] Schult) generally limited annual grasses more than other treatments. Most notably, forage kochia (Bassia prostata [L.] A. J. Scott) reduced exotic annual grasses less than crested wheatgrass and crested wheatgrass planted with forage kochia. This suggests that if forage kochia will be planted, it should be used in conjunction with perennial bunchgrasses in efforts to revegetate exotic annual grass—invaded sagebrush steppe. Established native vegetation also greatly reduced exotic annual grass reinvasion. Though some differences existed among established vegetation treatments, our study highlights that established perennial vegetation prevents redomination by invasives after exotic annual grass control.

Controlled burning timed in early summer can dramatically change the species composition of annual rangeland the following season. Although this has been well documented, the longevity of these shifts has not. Presented is a case study of a single 200-ha burn to begin to understand how long plant communities and biomass production remain diverged between burned and unburned annual rangeland. Species composition and biomass production were monitored before and for 3 yr after burning. Burning drastically reduced medusahead (Taeniatherum caputmedusae; P < 0.01) the following year from 69% in the control to 4% cover in the area burned. In the same year, filaree (Erodium spp.; P < 0.01) filled in the area left vacant, subsequently lessening production (P < 0.01) in the burn area by over half that of the control. No difference existed in the occurrence of native wildflower species due to fire. Three consecutive drought years following the burn shifted the control from medusahead dominance to filaree in a linear fashion. At the same time, in the burned area medusahead cover increased fourfold between 1 and 3 yr after the burn. By 3 yr post burning, the area had 4% more medusahead cover than the control and was equal in filaree, rose clover (Trifolium hirtum), and soft brome (Bromus hordeaceus) cover. Our results suggest that a controlled burn followed by drought can cause the divergence in species composition and production to become void in as little as 3 yr after a well-timed burn in a low-elevation annual rangeland system.

In sagebrush (Artemisia tridentata Nutt.) ecosystems, expansion and infilling of conifers decreases the abundance of understory perennial vegetation and lowers ecosystem resilience and resistance of the once shrub grass—dominated state. We prescribed burned or cut juniper (Juniperus spp. L.) and pinyon (Pinus spp. L.) trees at 10 sites across the western United States. We measured vegetation cover and density on untreated and treated plots 3 and 6 yr after treatment across a gradient of pretreatment tree dominance as quantified by the tree dominance index (TDI); (tree cover)/(tree shrub tall grass cover). We analyzed plant responses by functional group using mixed-model analysis of covariance, with TDI treated as a covariate. As tree cover increased and TDI exceeded 0.5, shrub cover declined to < 25% of the maximum on untreated plots. Although total shrub cover recovered on burned plots to untreated percentages 6 yr after treatment, sagebrush cover was still 1.1–0.6% on burned plots compared with 13.9–0.5% on untreated plots across the range of 0–1 TDI. Tall grass cover increased to 25.4–9.4% for burn plots and 24.3–22.4% on cut plots from 0–1 TDI 6 yr after treatment. Cheatgrass (Bromus tectorum L.) increased on prescribed fire and on cut treatments, especially at higher pretreatment TDI. However, ratios of cheatgrass to tall grass cover were much lower on cut than burn plots. To retain the shrub, especially sagebrush, components on a site and increase ecosystem resilience and resistance through increases in tall grasses, we recommend treating at low to mid TDI using mechanical methods, such as cutting or mastication. Effects of fire and mechanical treatments implemented at different phases of tree dominance create different successional trajectories that could be incorporated into state-and-transition-models to guide management decisions.

Mitigating runoff and associated erosion is a fundamental challenge for sustainable management of rangelands. Hillslope runoff and erosion are strongly influenced by ground cover; thus, a strategic management option exists to increase cover with slash from woody plant removal activities, particularly on lands experiencing woody plant expansion. Most studies assessing slash effects on runoff and erosion have been limited to moderate slopes; however, substantial portions of rangelands exist on steeper slopes where the effectiveness of slash application is less clear. On a steep (30% ± 5%) slope that had been encroached by piñon and juniper trees, we evaluated the effectiveness of slash in reducing runoff and erosion using a portable rainfall simulator (100-yr return period events). Although total runoff did not differ across slash levels, there was marginal evidence of a difference associated with vegetation cover. Sediment yield for plots with low vegetation cover (< 13% cover) was 3.4 times greater than those with high cover, while plots with slash present (≥ 30% cover) experienced 5.4 times less sediment yield than plots without slash. These results extend findings from moderate to steep slopes, highlighting the potential efficacy of slash application for reducing erosion in steep-sloped rangelands.

Diet selection is an important driver of ecosystem structure and function that is difficult to measure. New spectroscopic instruments are available for evaluating their applicability to ecological field studies. The objective of this study was to compare near-infrared reflectance spectroscopy (NIRS) to Raman spectroscopy of fecal samples for predicting the percentage of honey mesquite (Prosopis glandulosa) in the diet of ruminally fistulated cattle fed three different hay diets and compare them for their ability to discriminate among the three base diets. Spectra were collected from feces from a feeding trial with mesquite fed at 0%, 1%, 3%, and 5% of the diet and base hay diets of timothy hay (Phleum pratense), Sudan hay (Sorghum sudanense), or a 50:50 combination of Bermudagrass hay (Cynodon dactylon) and beardless wheat hay (Triticum aestivum). NIRS and Raman spectra were used for partial least squares regression calibrations with the timothy and Sudan hays and validated with the Bermudagrass/ beardless wheat hay diets. NIRS spectra provided useful calibrations (r² = 0.88, slope = 1.03, intercept = 1.88, root mean square error = 2.09, bias = 1.95, ratio of performance to deviation = 2.6), but Raman spectra did not. Stepwise discriminant analysis was used to select wavenumbers for discriminating among the hays. Fifteen of 350 possible wavenumbers for NIRS spectra and 29 of 300 possible wavenumbers for Raman spectra met the P ≤ 0.05 entry and staying criteria. Canonical discriminant analysis using these wavenumbers resulted in 100% correct classification for all three base diets, and the Raman spectra provided greater separation than NIRS spectra. Discrimination using Raman spectra was primarily associated with wavenumbers associated with undigestible constituents of the diet (lignin). In contrast, discrimination using fecal NIRS (f.NIRS) spectra was primarily associated with wavenumbers associated with digestible constituents in the diet (protein, starch, and lipid). We believe that Raman spectroscopy deserves further investigation as a quantitative technique in ecological field studies.

In the western United States, the management and use of public lands for livestock grazing is a frequent source of conflict among environmentalists, federal agencies, and ranchers. Since at least the early 1980s, the rhetoric of the “sagebrush rebellion” has reinforced a public perception that ranchers are both antigovernment and anticonservation. Sustainable management of public lands used for livestock grazing depends on both federal agency personnel, who enforce regulations, and ranchers, who use the land and implement management plans on a day-to-day basis. As a result, the attitudes of ranchers toward conservation can have a significant impact on the overall ecological health of public rangelands. We conducted a study of ranchers in southeastern Arizona and southwestern New Mexico using Q Methodology to understand their views and motivations about ranching, conservation, and the government. Our results show three complex viewpoints, which we term radical center ranchers (20% of variance), innovative conservationists (19% of variance), and traditional ranchers (12% of variance). A commitment to conservation and corresponding lack of anticonservation sentiment is held across these viewpoints. Mistrust of government coexists with conservation values for two groups. This information is useful for finding common ground between ranchers and government officials, conservationists, and extension agents on range management and conservation goals.