Following a wildfire or a prescribed fire, the recovery of rangeland vegetation is a critical consideration for restoring wildlife habitat, ecosystem services, and grazing value. Rangeland managers need to know when to resume grazing after fire to conserve rangeland resources and accomplish management objectives. To shed light on this issue, we conducted a meta-analysis of published research investigating the role of grazing after fire on vegetation recovery. Our search of two scientific databases found 18 articles with sufficient information to be comparable, mostly from the western US. To compare effect sizes, we conducted a meta-regression using moderators of precipitation, grazing utilization, fire season, years deferred from grazing, fire severity, and type of grazing animal, among others. We found that grazing within a few years after fire slightly reduced perennial grass cover compared with ungrazed areas, but type of grazing animal did not matter. Increasing precipitation and decreasing grazing utilization moderated this reduction in cover. Perennial grass cover in grazed plots decreased slightly as years after the fire increased. Resting an area from grazing after fire had no effect on perennial grass cover. Grazing after fire reduced annual grass cover compared with ungrazed areas and varied depending on precipitation and grazing utilization. Native forb cover was not affected by grazing after fire, though forb cover increased with spring fire and decreased with summer fire. In our analysis, grazing within a few years after fire did not affect herbaceous production. Our work provides a synthesis of effects on vegetation of grazing after fire and describes gaps in our current knowledge. We recommend including information on livestock management, including timing and intensity of grazing and season and duration of rest in future studies.
Spatial covariance is a metric used to delineate grassland cores and track state transitions driven by woody encroachment in rangelands, and it does so by calculating the degree of spatial coexistence between functional groups like grasses and trees at different scales. Spatial covariance is being used in biome-scale frameworks aimed at combatting woody plant encroachment and supporting grassland conservation, but little is known about how spatial covariance relates to on-the-ground vegetation metrics. Here, we begin to address this knowledge gap by comparing tree-grass spatial covariance (0.81 ha scale) to a variety of established, field vegetation structure metrics. Generalized additive models revealed that relationships between spatial covariance and field-based vegetation metrics were weak to moderate (deviance explained ranging from 10% to 47%). Tree density had the strongest relationship with spatial covariance (deviance explained = 47%): tree density nonlinearly decreased to near-zero when spatial covariance became positive. Average visual obstruction and visual percent grass cover had the weakest relationships with spatial covariance (deviance explained = 13% and 10%, respectively). The stronger tie between tree density and spatial covariance and the very weak link between dominant vegetation cover aligns with the intended usage of spatial covariance in rangeland management, which is to locate treeless grassland cores (i.e., spatial covariance values near zero) and prioritize them for defending “core” rangeland habitats. This also aligns with current applications of spatial covariance in grassland conservation as a metric of early warning, variation, intactness, and boundary strength, not of central tendencies or dominance. Additional testing at different scales and in different ecosystem contexts will help to further understand how spatial covariance relates to other field vegetation metrics.
Water availability is the primary determinant of dryland ecosystem structure and function, yet the effects of understory removal and precipitation variability on water partitioning remain poorly understood in big sagebrush rangelands. We investigated how intensive grazing (understory removal) and supplemental spring precipitation affect actual evapotranspiration (AET), water flux partitioning, and shrub growth in Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) communities in the Upper Green River Basin, Wyoming. We established replicated exclosures at three sites, applied understory removal and water addition treatments, and measured soil water dynamics and big sagebrush leader growth during the 2022 (dry) and 2023 (wet) growing seasons. We supplemented field measurements with SOILWAT2 simulations to partition AET into transpiration and evaporation. Interannual precipitation variability exerted the strongest control on AET, which ranged from 68 to 94 mm in 2022 to 118–156 mm in 2023. Understory removal had minimal effects on total AET but increased evaporation, particularly when additional water was supplied. Simulated AET closely matched field observations, validating model predictions. In the dry year, understory removal increased big sagebrush leader growth, suggesting competitive release under water-limited conditions, whereas treatment effects were negligible in the wet year. Evaporation exceeded transpiration across all treatments, comprising the dominant water loss pathway. Our results indicate that while simulated intensive grazing has limited immediate effects on ecosystem-scale water balance, it may shift water partitioning toward evaporation and promote shrub dominance during drought years. Maintaining herbaceous cover will be important for reducing bare-soil evaporation under projected increases in temperature and evaporative demand in big sagebrush rangelands.
The spread of invasive plants has significant economic impacts. Quantifying such economic impacts is important for management purposes. In Oklahoma, the invasive plant, Lespedeza cuneata (L. cuneata), is known to have significant ecological impacts on grassland ecosystems; however, the economic loss associated with its spread is yet unknown. The lack of quantification of the economic impact of L. cuneata can hinder effective management efforts and complicate the ability of policymakers and landowners to justify investments in prevention and control measures. In this study, we aimed to assess the economic impacts associated with L. cuneata spread in Oklahoma. To achieve our objectives, we first conducted a Monte Carlo simulation using L. cuneata presence records from citizen science data to determine its spread across the state of Oklahoma within a 5-yr period. We then used the Impact Analysis for Planning input–output model to quantify the direct, indirect, and induced economic impact of L. cuneata. Our results showed that L. cuneata will continue to spread in Oklahoma. Moreover, L. cuneata is estimated to affect the local economy of Oklahoma by approximately US $37 million within 5 yr, under the most extreme case scenario and the assumption that no new preventive management measures were implemented. These findings can contribute to incentivizing landowners and decision-makers to develop long-term management and monitoring strategies for L. cuneata control.
Different livestock species can alter soil nutrient dynamics in tropical pastures, but these effects remain poorly documented in seasonally flooded systems. We compared soils under Nellore cattle (Bos indicus) and Mediterranean water buffalo (Bubalus bubalis) in flooded and non-flooded grazing areas of a seasonally flooded, sub-humid tropical pasture in southeastern Mexico. We evaluated total and inorganic pools of surface soil C, N, and P, potential net C (PNCMR) and N mineralization rates (NNM), nitrification (NN), ammonification (NA), exchangeable base cations (Ca, Mg, K, and Na), and physicochemical soil properties (CEC, EA, pH). Effects of livestock species, grazing zone, and their interaction were assessed using linear models with heteroscedasticity-consistent inference, and multivariate patterns were examined using PCA and PERMANOVA. Livestock species seem to affect NH₄⁺, NO₃⁻, PNCMR, C:N ratio, and NNM. Water buffalo soils were associated with higher NH₄⁺, NO₃⁻, and PNCMR, whereas Nellore cattle soils were associated with higher NNM. Grazing zone affected P-Bray, CEC, and exchangeable Ca and Mg, with higher values in flooded areas. Significant livestock × grazing zone interactions were detected for PNCMR, C:N ratio, CEC, Na, Ca, and Mg, suggesting that species effects depend on hydrological context. Overall, our results indicate that livestock species and flooding jointly structure soil biogeochemical functioning in tropical pastures, especially C turnover, inorganic N dynamics, and cation retention.
Natural resource managers strive to improve restoration efficiency across the vast network of public lands of the United States, seeking the best return on investment through innovation, geographic prioritization, and adaptive management. This challenge is exemplified by ecosystems dominated by sagebrush (Artemisia spp.), which occur across the western United States and have been degraded by increasing wildfire frequency driven by invasive plant spread, among other factors. However, both costs and effectiveness of sagebrush restoration can vary spatially due to management practices in addition to biotic and abiotic factors, and characterizing this variation could inform broad-scale planning. We leveraged published models of sagebrush recovery and treatment costs to predict and evaluate cost-effectiveness of aerial and drill seeding Artemisia spp. across 429 718 km2 that overlapped 12 US states. Compared to natural recovery, effectiveness for both methods was generally low, yet effectiveness was often greater, and costs were always greater, for drill than aerial seeding, resulting in slightly higher cost-effectiveness on average for drill seeding. Cost-effectiveness for both treatments increased near major roads and in areas with more repeated burns. Cost-effectiveness also increased with predisturbance cover of sagebrush but decreased with herbaceous cover. However, we also identified areas where aerial seeding was more cost-effective than drill seeding, particularly with greater slope. Our results provide spatially explicit estimates and potential mechanisms of cost-effectiveness for two common seeding methods for sagebrush, which can help prioritize limited resources, guide land use, and improve restoration efficiency and effectiveness across public rangelands of the western United States.
Cheatgrass (Bromus tectorum) is an exotic, invasive, annual grass that rapidly invades and dominates areas in North America and reduces abundance, survival, and diversity of native plants and animals. A variety of methods have been used to control cheatgrass, but herbicides seem to consistently produce the best results. Indaziflam is a pre-emergent herbicide that prevents germination and is especially effective on annual grasses. We used a randomized block design to evaluate the effectiveness of indaziflam to reduce cheatgrass cover in two vegetation communities in northeastern Colorado, and assessed the vegetation response to treatments with special focus on habitat for northern bobwhite (Colinus virginianus), a species of conservation concern in Colorado and throughout their distribution. In the sandsage rangelands vegetation community during June sampling, indaziflam reduced cheatgrass cover from an average of 61% cover (range, 53–70%) to an average of 5% cover (range, 4–6%). In the river bottom vegetation community during June sampling, indaziflam reduced cheatgrass cover from an average of 13% cover (range, 10–18% cover) to an average of 5% cover (range, 1–9%). With the reduction in cheatgrass cover, we documented increases in forb, bunchgrass, and bare ground cover in certain seasons and vegetation communities, which are important components of northern bobwhite habitat. We found a negative response of forbs up to 1 yr posttreatment, but by 2 yr posttreatment, forb cover was greater than in untreated control plots. Overall, indaziflam treatments tended to result in better bobwhite habitat but this benefit was not apparent in all seasons and habitat types.
Annual grass invasion in the western United States decreases biodiversity, biocrusts, and perennial vegetation and escalates the risk of large frequent wildfires. These effects degrade critical wildlife habitat and reduce quality livestock forage. In addition, altered fire regimes threaten life and property as well as greatly increase fire suppression costs. Controlling annual grasses to negate these negative impacts is a common management objective. Indaziflam, a more recently developed pre-emergent herbicide with longer soil activity, is increasingly used for annual grass control. More information on the effects of indaziflam on plant biodiversity, biocrusts, and perennial vegetation is needed because of contradictions in reported effects and inconclusive results. We investigated the effects of indaziflam application at 14 annual grass-invaded sites in bunchgrass rangelands in eastern Oregon. Ventenata (Ventenata dubia (Leers) Coss.) and medusahead (Taeniatherum caput-medusae (L.) Nevski) were the dominant annual grasses at the study sites. Indaziflam was applied at a rate of 73 g ai · ha−1 in late August to early September in either 2019 or 2021. Plant community response to indaziflam application was measured for 3 yr posttreatment. Indaziflam effectively controlled invasive annual grasses for the duration of the study. Perennial vegetation cover and density increased substantially with indaziflam control of annual grasses. Plant biodiversity increased with indaziflam application, with it being 40% greater in the indaziflam treatment compared with the untreated control by the third year. Indaziflam control of annual grasses resulted in considerable increases in biocrusts and bare ground, and decreases in litter. The cumulative effects suggest that indaziflam increased plant community resistance to reinvasion by annual grasses and decreased wildfire probability. Indaziflam appears to be effective at controlling invasive annual grasses for multiple years and promoting perennial vegetation, biocrusts, and plant biodiversity.
The shortgrass prairie of the Great Plains is one of the most endangered ecosystems in the United States, having faced significant losses and alterations due to anthropogenic land conversion and species introductions. Historically, the American bison (Bison bison) acted as a keystone species to the shortgrass prairie ecosystem, providing grazing and wallowing disturbances important to promoting grassland ecological diversity. However, the dietary preferences of these reintroduced bison herds are not well understood in today’s novel landscapes but methods such as stable isotope analysis may be advantageous in understanding the diets of bison in open environments. We analyzed the stable carbon (ẟ¹³C) and nitrogen (ẟ¹⁵N) isotopic compositions of open-ranging bison dung and plant samples and applied them to the MixSIAR stable isotope mixing model to test the relative contributions of different plant groups to bison diet in shortgrass prairie with an assemblage of native and nonnative plant species. Our results indicate that forbs may contribute the most to bison diet in early summer, and that native species made up a greater composition of consumed plants. This study highlights the potential of stable isotope analysis as an effective tool for investigating wild and/or open-ranging animal diets. Additionally, our findings lay a foundation for providing important insights for managing bison interactions with plant communities in altered shortgrass prairie ecosystems within the Northwestern Great Plains/Northwestern Glaciated Plains ecoregion with invasive cool-season grasses and other nonnative plant species.
Rangelands are a critical forage base for the livestock industry and provide ecosystem services such as open space preservation, wildlife habitat, and biodiversity. However, few long-term grazing studies have quantified the economic trade-offs associated with implementing conservation-oriented grazing systems at operational ranch scales. This study evaluated the profitability of traditional range management (TRM; continuous season-long grazing) compared to collaborative adaptive rangeland management (CARM; a stakeholder-driven adaptive rotational system) using yearling steers over a 10-year period (2014–2023) at the Central Plains Experimental Range (CPER) in a semiarid, shortgrass steppe of northeastern Colorado. We used steer weight gain data, historical Colorado cattle prices, and system-specific labor and infrastructure costs to determine economic outcomes for TRM and CARM. A Monte Carlo simulation (100 000 iterations) based on historical livestock price distributions was used to calculate annual and 10-year total net revenue and returns to labor and management for both grazing strategies. TRM was more profitable with an 8.8% higher mean net ($884 749) compared to CARM ($812 655). Further, total forecasted returns to labor and management was 78.4% higher ($243 889) for TRM compared to CARM ($136 715) due to decreased animal performance and higher infrastructure costs with CARM. While CARM improved some ecosystem service outcomes, such as increased vegetation heterogeneity, shrub cover, and maintenance of viable habitats for several native grassland bird species of conservation concern, the grazing strategy reduced livestock production and relative profitability. These findings confirm that intensive rotational systems may carry financial trade-offs under typical market and climate conditions in the semiarid shortgrass steppe. This research is relevant to ranchers because it quantifies the cost of achieving ecologically beneficial outcomes through adaptive rotational grazing. Further, it provides insight for ranchers considering system changes and policymakers aiming to design incentives that reflect both the benefits and costs of conservation oriented grazing management on working rangelands.
Pricklypear (Opuntia spp.) occurs on about 28% of rangelands (10.3 million ha) in Texas and coverage is expanding due to overgrazing and mechanical disturbance. Although a native species to Texas rangelands, pricklypear can become so dense that it outcompetes other native vegetation, suppresses forage production, inhibits biodiversity, and limits livestock movement within pastures. Picloram (Pc) and picloram + fluroxypyr (Pc + F) have been effective at managing pricklypear, however, a herbicide combining picloram, fluroxypyr, and aminopyralid (Pc + F + A) has been reported to increase speed of plant mortality and enhance overall efficacy. We examined varying individual plant treatment and ground broadcast application rates consisting of combinations of picloram, fluroxypyr, and aminopyralid compared to standard industry rates of picloram and picloram + fluroxypyr on overall pricklypear mortality using individual plant treatment and ground broadcast applications across 13 sites on Texas rangeland from 2016 to 2018. Individual plant treatment Pc + F + A (1%) achieved the highest mortality rate of 98.0 ± 3.5% two years post-application, significantly outperforming Pc (1%) at 76.4 ± 19.3%, while including aminopyralid at lower rates (0.75% and 0.5%) yielded comparable control at 96.2 ± 8.2% and 89.6 ± 14.5%, respectively. Ground broadcast applications showed no significant differences in mortality between Pc + F + A (2 336 mL/ha), Pc (2 336 mL/ha), and Pc + F (4 672 mL/ha), ranging from 66.8 ± 21.3% to 78.1 ± 20.2%, though lower rates (8 oz/ac and 16 oz/ac) reduced control to 44–59% ± 25%. These findings highlight the efficacy of higher treatment rates for consistent pricklypear management, with some lower rates offering similar outcomes, providing flexible options for rangeland managers.
Monitoring plant species composition at management-relevant scales remains a persistent challenge in rangeland ecosystems. High-resolution imagery from unoccupied aerial vehicles (UAVs) offers a promising solution, but high sensor costs, the need for extensive field training data, and the difficulty of covering large areas have hindered widespread adoption. We evaluated the performance of UAV-based machine learning models for plant species classification and transferability to sites without training data across 14 big sagebrush (Artemisia tridentata L.) steppe landscapes in the northern Great Basin, USA. We tested models for 18 common overstory plant species in different functional groups including shrubs, Artemisia arbuscula Nutt. (low sagebrush) and Ericameria nauseosa (Pall. ex Pursh) G.L. Nesom & Baird (rubber rabbitbrush), and the perennial bunchgrass Pseudoroegneria spicata (Pursh) Á. Löve (bluebunch wheatgrass). Using Structure-from-Motion photogrammetry and a stacked ensemble learning approach, we achieved a mean classification accuracy of 92.1% (95% CI, 90.9–93.2%) and a weighted F1 score of 91.5% (95% CI, 90.2–92.8%), indicating strong performance despite a highly imbalanced dataset dominated by a few common species. Models trained with low-cost red, green, and blue imagery performed nearly as well as those using multispectral data, with only about a 1% difference in F1 score. However, model transferability was limited: classification accuracy declined sharply at sites where species composition differed from training data, with F1 scores ranging from <0.09 to >0.90 across test sites. These results suggest that although low-cost UAVs can produce accurate and scalable species maps, reliable application across diverse rangelands will require strategic field sampling or shared training datasets. Our findings provide practical guidance for researchers and land managers seeking to incorporate UAV technology into biodiversity monitoring, restoration planning, and invasive species management.
Mule deer (Odocoileus hemionus) populations have been declining across much of their range, often due to habitat alteration. Habitat alterations, including the introduction of non-native annual grasses and the expansion of pinyon–juniper (PJ) forests on sagebrush ecosystems, are changing resource availability compared to historical conditions. Extensive habitat restoration has been completed across the State of Utah to foster plant communities that better reflect historical conditions and optimal mule deer habitat. We investigated how patch retention times differ on eight different habitat restoration treatment types and random locations during summer and winter across the State of Utah, to evaluate the efficacy of restoration treatments for migratory mule deer, as retention time is expected to reflect resource availability. We developed seasonal moving-window Brownian Bridge Movement Models for individual mule deer (n = 593 animals), and intersected occurrence distributions (OD) with habitat restoration treatments and randomly generated background landscape polygons. We quantified patch retention time as the number of days individuals’ OD overlapped treatment or random polygons during each season, using a Poisson regression. In winter sites treated to remove PJ, both with (56.5 days, 95% CI [29.3, 108.0]) and without seeding (55.3 days, 95% CI [29.1, 105.8]), as well as sagebrush restoration sites (59.0 days, 95% CI [30.6, 114.8]), had increased retention times when compared to the landscape average (41.9 days, 95% CI [20.7, 84.1]), with effects decreasing 5+ years post-treatment. Retention times in summer were longer across all treatment types in the 2–4-year post-treatment age class (37.5 days, 95% CI [26.3, 53.1]) compared to the landscape average (28.6 days, 95% CI [25.7, 31.8]). Our results demonstrate the positive effects of habitat restoration through increased patch retention times on mule deer winter and summer range and may suggest follow-up treatment 5+ years after initial treatment to maximize mule deer use.
An optimized sampling strategy is critical for effective environmental monitoring, bridging between local data collection over limited sites and inference over a broader study area, especially for those environmental attributes subject to large spatial and temporal variations.This study leveraged a unique 10-ha rangeland dataset from the Central California Coast to determine the optimal sample size required to quantify peak standing crop (PSC) at given levels of accuracy and statistical significance. Imagery from drone and satellite were fused and calibrated with field clipping data to map PSC at a 0.3 × 0.3 m resolution. We assessed the spatial and temporal variability in PSC to characterize its true population and landscape variability for both a wet and dry year. The mean PSC was 2.8-fold higher in the wet year (2 793 kg · ha−1) than in the dry year (983 kg · ha−1), whereas the coefficient of variability among surrounding quadrats was 50% higher in the dry year and showed a logarithmic decrease with increasing PSC levels indicating the need for a greater number of samples in years having lower production. We found that 10 to 12 randomly selected samples provided accuracies within ±20% of the catchment true mean at a confidence level of 95% in the drier year, whereas only five samples were required in the wetter year. Furthermore, the use of the 0.3 × 0.3 m versus 1 × 1 m quadrat achieved similar sample-size requirements, whereas providing a ∼10-fold savings in field work time/effort. These findings provide data-driven guidance on the optimized field sampling for accurate PSC monitoring and assessment to guide policy and management decisions. The statistical evaluation framework leveraging very high-resolution remote sensing can be applied to other systems for the sampling strategy optimization to capture the true spatial or temporal variability.
Successful rangeland revegetation on western rangelands can be challenging with natural and human-related influences. Defoliation from a wide range of vertebrate and invertebrate grazers can reduce seedling growth and increase plant mortality, thereby impeding restoration efforts. Understanding how herbivory can impede plant establishment and growth may help predict restoration outcomes and create effective solutions for rangeland restoration. Bottlebrush squirreltail (Elymus elymoides (Raf.) Swezey), a native perennial grass species often used in seed mixes, stabilizes soils, provides quality forage, and competes with annual plants. The purpose of this study was to identify the impact of herbivory on bottlebrush squirreltail seedling damage and mortality. This study was conducted on the Utah Test and Training Range (UTTR) in western Utah, USA, tracking herbivory, seedling emergence, and timing and cause of seedling death. We placed cameras in 28 randomly placed plots arranged in a randomized split-plot design with fenced and unfenced plots and seeded with two rows of bottlebrush squirreltail. We tracked individual seedlings and recorded their condition (alive, dead, grazed or damaged), comparing establishment and survival between fenced and unfenced plots. Seed predators reduced initial seedling establishment in unfenced plots by four times (P = 0.0002). Seedlings were seven times more likely to survive in fenced vs. unfenced plots. Of total seedling mortality, 73.6% of seedling death was caused by herbivory from black-tailed jackrabbit (Lepus californicus), invertebrate herbivores, and Botta’s pocket gopher (Thomomys bottae). Strategies to mitigate the effect of herbivores should be considered to increase seeded plant establishment during restoration efforts. These results highlight the broader need for restoration projects in arid and semi-arid ecosystems to account for herbivore communities when planning seeding projects, as early-stage herbivory can strongly limit plant establishment across many species and ecosystems.
Dryland restoration methods often focus on management strategies to improve seedling establishment and survival under a range of abiotic and biotic stresses, such as drought and invasive species. Despite intensive research, conventional restoration efforts often result in failure, as few seeds successfully establish to become adult plants. Sprigging, or replanting of living grass segments, has been used effectively for years in agricultural grass fields and turf plantings. In a restoration setting, sprigging, or planting vegetative starts, is often used in wetlands and coastal dunes. Sprigging quickly establishes self-sustaining grass communities in these systems. If this technology could be harnessed and applied to dryland systems, it has the potential to greatly improve restoration outcomes. A review of the literature suggests that plant adaptations to drought, fire, and grazing in drylands may make it feasible to plant perennial grass species via sprigging in these systems. Preliminary work indicates that planting sprigs from grass crowns may be a feasible form of restoration, particularly as storage and planting methods are refined. However, major research is needed before sprigging will be a viable dryland restoration technology. For example, improved cultivars of native species may need to be developed to enhance sprigging, as has been done in agricultural and turf settings. Trials should be conducted to determine appropriate planting times and techniques for optimal establishment, which may differ by species. Soil treatments or hormone amendments may be able to improve sprig viability at planting. We hope others will use this paper as a springboard to direct future research on the potential of sprigging in dryland systems.
Grassland degradation is affecting approximately 90% of the Tibetan Plateau, and thus cultivated grassland construction has emerged as a pivotal strategy for ecological restoration and sustainable development of the livestock sector. Despite government efforts to breed and promote superior forage varieties, adoption by herders depends on the attributes of forage, perception of varieties, and socioeconomic characteristics. Using a discrete choice experiment, we investigated the valuations of herders regarding different attributes of forage varieties, and identified key factors that influenced their preferences. The results showed that herders in the northeastern Tibetan Plateau region were willing to adopt new forage varieties when the variety attributes matched their needs and preferences. Their perceptions of new varieties also significantly influenced adoption. Socioeconomic characteristics, particularly geographical region, forage cultivation experience, and purchase experience, substantially affected the marginal willingness to pay for new varieties among herders. Based on these empirical insights, we recommend economic benefit labeling, region-specific promotion strategies, and targeted training to enhance the knowledge and perception of herders, thereby improving the adoption of new forage varieties.
In recent decades, mule deer (Odocoileus hemionus) populations have declined in many areas primarily due to habitat loss. This loss can be attributed in part to the expansion of juniper (Juniperus occidentalis Hook.) into sagebrush (Artemisia spp. L.) and aspen (Populus tremuloides Michx.) plant communities, reducing shrub and understory vegetation, respectively. This diminishes forage availability which negatively impacts mule deer as malnutrition is a leading cause of adult mortality. Research has evaluated how mule deer respond to juniper expansion in sagebrush communities, but few studies have examined their response to expansion into aspen communities. Previous studies also demonstrated that, in addition to changes in vegetation cover, mule deer populations can be impacted by interactions with other ungulates and human development. We evaluated the relative importance of these factors and juniper for influencing mule deer occupancy in the Steens Mountain area of southeast Oregon, by analyzing data collected from game cameras deployed June–August 2020–2022 in a single-season occupancy model. We expected early to mid-successional juniper woodlands and areas with more aspen vegetation to have higher occupancy rates compared to late-successional or treeless sites. We predicted higher occupancy in areas with more understory vegetation, reduced elk, cattle, and horse presence, and farther from roads. We found that mule deer occupancy was highest in areas with intermediate (∼15–30%) overall tree cover. We also found that greater herbaceous cover (perennial and annual) and shrub cover (sagebrush and non-sagebrush) was associated with higher occupancy rates. Additionally, mule deer occupancy was higher in areas with less elk presence and more cattle presence. These findings highlight the importance of maintaining intermediate tree cover and abundant understory vegetation to support mule deer populations. Managers can use these insights to prioritize and balance juniper treatments that benefit mule deer as well as other sagebrush-obligate species.
Carbon markets present an emerging opportunity for ranchers to generate additional income while continuing livestock production. However, little research has explored ranchers’ willingness to join these markets or the factors influencing participation. To address this gap, we surveyed 506 ranchers across ten states in the Front Range and Great Plains regions, USA in January 2024. We found that ranchers enrolled in a conservation easement, those who have participated in conservation programs, those who believe their community would support their participation, and those who lack sufficient knowledge to approve or disapprove of the carbon market were more willing to enroll. Conversely, skepticism surrounding the carbon market reduced willingness to participate. Knowing someone enrolled in the market, having a land management plan, annual income, relying on agriculture for 50% or more of household income, and ranch goals had no significant impact on willingness to enroll. In general, ranchers are skeptical of the carbon market and lack trust. Carbon companies should improve transparency regarding costs, payments, and enrollment processes. Additional research is needed to explore strategies for building trust and addressing ranchers’ concerns about carbon markets.
Resource matching can be a common assumption that underlies anthropogenic rangeland improvements for wildlife or livestock. Countless resources are spent on targeted vegetation manipulations for both livestock and wildlife, but selection for improved areas has not been well quantified in livestock. This case study investigates whether cattle exhibit preferential use of historically improved rangeland sites within sagebrush steppe ecosystems, and whether these effects are relevant long-term compared with inherent landscape heterogeneity. We used a generalized linear mixed-effects resource selection function on Global Positioning System points collected at a fix rate of 2 h from a subset of animals grazing throughout 14 pastures (totaling 13 079 ha) over 3 yr to investigate cattle distribution in relation to historical rangeland improvements. These consisted of various methods for reducing woody plant cover and increasing forage production, most followed by grass and legume reseeding. Overall selection for treated areas was positive (0.16, P < 0.0 0 01), but highly variable (pasture estimates range from-1.81 to 0.77). Differences in enhanced vegetation index (EVI) accounted for 25% of the variation in treatment selection, whereas herbaceous production did not have an appreciable effect on treatment selection. Within individual pastures, the effects of landscape variables (distance to water, slope, herbaceous production, EVI, tree cover, and shrub cover) were more variable than treatment effects and on average 2.4-fold more influential to selection than anthropogenic treatments. Still, the combined effects of all landscape variables accounted for only 8% of the variation in site selection. The observed inconsistency among selection patterns underscores the complexity of large herbivore resource selection behavior, and the statistical challenges to modeling that behavior. These results provide limited and inconsistent support for the hypothesis that large herbivores select long-term (5–20 yr post establishment) for range improvements in relation to their forage quality/quantity in a resource-matching manner.
