Rangeland Ecology & Management最新文献

{"title":"Seed Storage Conditions Shape Germination Outcomes: Differing Responses in Two Closely Related Grass Species","authors":"Jenna LeBlanc,&nbsp;S. Eryn McFarlane","doi":"10.1016/j.rama.2025.07.015","DOIUrl":"10.1016/j.rama.2025.07.015","url":null,"abstract":"<div><div>Seed dormancy is a protective adaptation meant to reduce the risk of germination in unsuitable or unpredictable conditions. However, dormancy can complicate or undermine restoration efforts if care is not taken to understand how dormancy-influencing seed storage conditions can affect germination outcomes. Additionally, assuming that closely related species will respond similarly to the same storage and germination conditions may obscure important life history differences, potentially leading to ineffective or biased restoration strategies. We examined how seed storage conditions influence germination outcomes in two foundational grassland species (<em>Festuca hallii</em> [Vasey] Piper and <em>Festuca campestris</em> Rydb.) by subjecting seeds of both species to different combinations of storage duration, temperature, and moisture, before conducting a germination assay under identical controlled conditions. We found that the two species had drastically different responses. <em>F. campestris</em> exhibited low overall germination (13%), which was not meaningfully influenced by any of our storage treatment combinations. <em>F. hallii</em>, meanwhile, had a mean germination of 69%, which increased to 94% simply by soaking the otherwise untreated seeds for 24 h before the germination assay. Our findings highlight the importance of considering seed handling and storage as critical steps in the restoration pipeline, with the potential to significantly impact germination and establishment success. They also highlight the need to consider species-specific management strategies, even among closely related taxa, and for clear communication among seed suppliers, land managers, and restoration practitioners to ensure shared understanding of seed histories and conditions before planting.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 202-209"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145095846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Do Landownership Motivations Determine Land and Water Management? A Survey of Ranchers in California Rangelands","authors":"José L. Oviedo ,&nbsp;Lynn Huntsinger ,&nbsp;Nathan D. Van Schmidt ,&nbsp;Steven R. Beissinger","doi":"10.1016/j.rama.2025.09.005","DOIUrl":"10.1016/j.rama.2025.09.005","url":null,"abstract":"<div><div>Research on private ownership of rural land often draws on many factors in attempting to explain land use and management decisions, including landownership motivations. In this article, we present the results of a survey of private landowners in the Sierra Nevada foothills of Yuba, Nevada, and Butte counties (California), in a rangeland setting that is mostly open oak woodland intermixed with grassland and shrubland. We used factor analysis to identify landowner typologies based on the importance to respondents of various motivations for landownership. We then used regression models to analyze whether the identified typologies determine land and water management decisions. These decisions affect the size and distribution of shallow wetlands that provide key habitat for wildlife, particularly for the threatened California black rail (<em>Laterallus jamaicensis coturniculus</em>). Our results identified two typologies associated primarily with pecuniary motivations and four with nonpecuniary motivations. We also found that landowners driven by motives we termed <em>Profit</em> or <em>Lifestyle</em> were more likely to manage water-dependent areas and take actions affecting both wetlands and land uses, while those motivated by <em>Recreation</em> or land <em>Investment</em> were less likely to take any action. Property size was also a significant driver of management decisions. Our findings suggest the need for tailoring environmental schemes to different landowner typologies in the management of private rangelands.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 356-366"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145361714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cost-Effectiveness of Linear Fuel Breaks in Wildfire Management: A Case Study from Southern Idaho","authors":"Aaron Johnston,&nbsp;Kayla Johnston,&nbsp;Katherine D. Lee","doi":"10.1016/j.rama.2025.09.012","DOIUrl":"10.1016/j.rama.2025.09.012","url":null,"abstract":"<div><div>Across the western United States, wildfires have increased in both size and frequency, underscoring the need for cost-effective strategies to mitigate risk and support fire suppression efforts. Linear fuel breaks (LFBs)—strips of land where vegetative fuels are removed or modified—are intended to reduce flame lengths, slow fire spread, and improve access and safety for fire crews. The Bureau of Land Management (BLM) plans to expand its network of LFBs in the Great Basin by over 17 000 km. However, uncertainties remain regarding their effectiveness in reducing wildfire-related impacts. To address this knowledge gap, we estimate avoided wildfire costs attributable to fuel breaks in the Twin Falls BLM District of south-central Idaho. Our analysis focuses on the 2019 Pothole fire, which was contained in part due to the presence of LFBs. By developing a counterfactual simulated scenario in which the fire did not intersect the fuel breaks and using historic data on suppression expenditures, postfire rehabilitation costs, and grazing-related forage losses, we estimate the net economic benefits associated with fuel break presence. This case study provides actionable insights for land managers by quantifying the potential cost savings from fuel break infrastructure. Our findings indicate that in the northern Great Basin, LFBs may significantly reduce wildfire management costs, supporting their strategic deployment as part of a broader landscape-scale fire mitigation approach.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 406-416"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Steer Growth Performance and Enteric Gas Flux Across Backgrounding Phases in the Western Great Plains","authors":"Inés Mesa Gandolfo ,&nbsp;Justin D. Derner ,&nbsp;R. Mark Enns ,&nbsp;Larry A. Kuehn ,&nbsp;Melissa K. Johnston ,&nbsp;Sean P. Kearney ,&nbsp;Sara E. Place ,&nbsp;Edward J. Raynor ,&nbsp;John P. Ritten ,&nbsp;Anna M. Shadbolt ,&nbsp;Kimberly R. Stackhouse-Lawson ,&nbsp;Juan de J. Vargas ,&nbsp;Pedro H.V. Carvalho","doi":"10.1016/j.rama.2025.08.010","DOIUrl":"10.1016/j.rama.2025.08.010","url":null,"abstract":"<div><div>This study assessed the changes in growth performance and enteric gas flux of stocker steers across the postweaning phase and stocker phase of the production system in the western Great Plains. The objectives were to (1) evaluate growth performance and gas flux of steers originating from different production environments (e.g., diet and management) in the two phases of backgrounding, and (2) compare automated head-chamber system (AHCS)-measured enteric methane (CH_4, g CH₄ d⁻¹) emissions to predictions using Intergovernmental Panel on Climate Change (IPCC) Tier 2 methodology. In the winter postweaning phase, one group was stocked on shortgrass rangeland, and two groups were managed in drylot before all three groups were collectively stocked on summer rangeland. Steers winter-stocked on Colorado rangeland (hereafter, Colorado-grazing steers) doubled their average daily gain (ADG, kg steer⁻¹ day⁻¹) during the summer stocker phase on extensive rangeland. Conversely, steers that spent the winter postweaning phase in drylot in Nebraska (hereafter, Nebraska-drylot steers) or Colorado (hereafter, Colorado-drylot steers) had the same or reduced ADG in the stocker phase compared with the postweaning phase. Colorado-grazing steers produced 58% more CH₄ in the stocker phase than in the postweaning phase, whereas Nebraska-drylot steers emitted 11% lower CH₄ in the stocker phase than in the postweaning phase. Methane production was similar between phases for Colorado-drylot steers. Concomitantly, CH₄ intensity (g CH₄ kg⁻¹ ADG⁻¹) decreased for Colorado-grazing and Nebraska-drylot steers, whereas no difference was detected for Colorado-drylot steers between phases. A comparison of measured enteric CH₄ emissions to IPCC predictions for the same animal class and diet in each production phase revealed that predictions for five of six animal-phase combinations diverged from AHCS-measured CH₄ production. This longitudinal experiment suggests that accounting for the variation in gas flux across each phase in growing steers may inform assessments of the sustainability of beef cattle related to greenhouse gas mitigation strategies.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 247-257"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards integrated frameworks for assessing bird species richness using citizen science and geospatial data","authors":"Frank Juma Ong’ondo ,&nbsp;Qingmin Meng ,&nbsp;Domnic Kiprono Chesire ,&nbsp;Peter Njoroge ,&nbsp;Tariq Aqil ,&nbsp;Hafez Ahmad ,&nbsp;Serge Leugoue Kameni ,&nbsp;Philista Adhiambo Malaki","doi":"10.1016/j.rama.2025.08.013","DOIUrl":"10.1016/j.rama.2025.08.013","url":null,"abstract":"<div><div>Citizen science has become increasingly essential for assessing species population trends and guiding conservation strategies. However, integrating citizen science input and datasets with spatial analysis remains underutilized, despite its critical potential to enhance ecological understanding and inform targeted conservation efforts. This study utilized bird data from the Kenya Bird Map initiative (January 2019–December 2023), combining with satellite imagery processed through Google Earth Engine (GEE) over the same period, to investigate the environmental factors that influenced species richness in Nairobi National Park and its surrounding buffer zone. Our methodology incorporated multiple satellite-derived datasets, selecting key environmental variables based on their ecological relevance, spatial resolution, and temporal consistency. We focused on vegetation productivity and climatic factors as critical determinants of species richness, using NDVI and EVI to assess vegetation cover and evaluating the roles of precipitation, soil moisture, and temperature in shaping species distribution and habitat quality. A Generalized Linear Model (GLM) was applied to analyze the relationship between species richness and these environmental covariates. NDVI exhibited a significant positive association with species richness (0.280 ± 0.052, <em>P</em> &lt; 0.001), indicating that higher vegetation productivity supports greater bird diversity. Precipitation also had a positive effect (0.165 ± 0.056, <em>P</em> = 0.003), whereas soil moisture negatively influenced species richness (−0.159 ± 0.052, <em>P</em> = 0.002), suggesting that excessively wet conditions may reduce habitat suitability. Temperature did not exhibit a significant relationship (0.016 ± 0.043, <em>P</em> = 0.717). Nonlinear trends were observed, with intermediate levels of NDVI and soil moisture maximizing species richness. Interaction effects revealed that vegetation, precipitation, and soil moisture collectively influenced richness, highlighting the complexity of species-habitat associations. These findings emphasize the importance of sustainable land-use practices that align with conservation priorities to safeguard biodiversity in rapidly changing environments.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 218-229"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rangeland Resilience on the Brink: Unravelling Ecosystem Services and Degradation Drivers","authors":"Qurban Aliyar ,&nbsp;Marzieh Keshavarz","doi":"10.1016/j.rama.2025.10.007","DOIUrl":"10.1016/j.rama.2025.10.007","url":null,"abstract":"<div><div>Rangelands cover approximately 70-80% of Afghanistan’s land area and provide critical provisioning, regulating, supporting, and cultural ecosystem services that sustain rural livelihoods and biodiversity. Although ecological assessments quantify these ecosystem functions, local herders’ perceptions strongly influence grazing decisions, shape community engagement, and ultimately affect the success of resilience-building interventions. Consequently, understanding local perceptions is essential for designing interventions that align socio-cultural values with ecological realities. This study surveyed 200 households in Band-e-Amir National Park and the Shah-e-Foladi protected rangeland to document perceived ecosystem services and to identify drivers of perceived vulnerability to rangeland degradation. Respondents reported moderate-to-high awareness of provisioning services (fodder, fuelwood, and fiber) and of key regulating services (soil stabilization and water retention), but relatively limited recognition of supporting and cultural services. Overgrazing, shrub collection, and expansion of dryland farming emerged as the primary perceived threats to rangeland resilience. Multivariate regression analysis indicated that greater occupational dependency on rangeland resources and tenure insecurity were associated with higher perceived vulnerability, whereas higher household income was associated with lower perceived vulnerability. Notably, higher levels of social trust were also associated with increased perceived vulnerability, and greater awareness of ecosystem services heightened sensitivity to degradation risks. Taken together, these findings imply that integrated interventions—such as tenure reforms, livelihood diversification, community-based governance, and participatory education—tailored to local patterns of occupational dependence, tenure insecurity, economic capacity, social trust, and service awareness are likely to strengthen stewardship, reinforce ecosystem functions, and improve the resilience of Afghanistan’s rangelands.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 507-515"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drivers of the Fine- and Broad-Scale Distribution of a Woody Encroacher in a Montane Grassland","authors":"Gbenga F. Akomolafe,&nbsp;Dineo Mogashoa,&nbsp;Peter C. le Roux","doi":"10.1016/j.rama.2025.10.008","DOIUrl":"10.1016/j.rama.2025.10.008","url":null,"abstract":"<div><div>The encroachment of woody species into grasslands impacts these ecosystems globally. Identifying the environmental factors associated with encroaching species’ distributions can provide insights relevant to their management, especially when examined across different spatial scales. <em>Leucosidea sericea</em> is an endemic woody species that is encroaching in southern African grasslands, and has the potential for considerable negative socio-ecological impacts in the region. This study, therefore, investigates the factors predicting the distribution of <em>L. sericea</em> at 2 contrasting scales: at a fine scale, using data from one topographically heterogenous landscape, and at a broad scale using environmental conditions across the species’ global distribution. The distribution of <em>L. sericea</em> is accurately modelled at both scales. At the finer scale, the species tended to occur at lower elevations and in sites with high soil moisture, low wind exposure and lower non-woody vegetation cover, suggesting that its landscape-scale occurrence patterns are sensitive to both biotic and abiotic conditions. At a broader scale, precipitation and temperature variables were more important than soil conditions in predicting its distribution. Specifically, the species had the highest probability of occurrence at sites with cooler temperatures (8–17 °C) and wetter condition (precipitation of 300–550 mm) during the warmest quarter of the year. This suggests that the warmer and drier conditions associated with current climate change trends will potentially constrain the future distribution of the species, with upslope expansion to cooler altitudes a possible response to increasing temperatures. These findings highlight that the occurrence of <em>L. sericea</em> is correlated with multiple environmental factors, and suggests that its distribution is likely sensitive to further climate change. Consequently, under changing temperature, rainfall conditions and shifting land-use, monitoring of this species, particularly in areas suitable for its occurrence, should be considered a priority by rangeland managers, conservationists and other stakeholders to understand the need for its management. This study can serve as a framework for understanding occurrence patterns of encroaching species across different spatial scales.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 516-526"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145617653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Managing Guinea Grass Invasion With Cattle Grazing: Thresholds and Native Plant Recovery Across Rainfall Variability","authors":"Aaron C. Rhodes ,&nbsp;Kathryn E. Tisshaw ,&nbsp;Robert M. Plowes ,&nbsp;Eric Grahmann ,&nbsp;Jimmy Rutledge ,&nbsp;Bart Dupont ,&nbsp;Lawrence E. Gilbert","doi":"10.1016/j.rama.2025.10.006","DOIUrl":"10.1016/j.rama.2025.10.006","url":null,"abstract":"<div><div>Invasive grasses are altering ecosystems at an alarming scale, and precipitation variability will likely exacerbate change in invaded grasslands. Targeted grazing can mitigate the invasiveness of palatable invasive grasses, benefiting native plant communities and wildlife. This study examines the impact of targeted grazing on invasive Guinea grass (<em>Megathyrsus maximus</em>), a C4 perennial grass introduced for forage. Over 4 years, we studied cattle effects on Guinea grass in eight pastures on a 20,000-ha working ranch, across variable Guinea grass, precipitation, and cattle utilization characteristics. Our results demonstrate that targeted grazing surpassing 50% of Guinea grass tillers grazed reduces Guinea grass productivity, reproduction, and thatch accumulation, promoting native plant communities. We found that precipitation and cattle grazing interacted to mediate these effects. During wetter periods, grazing 50% of Guinea grass tillers reduced grass height from 85 cm to 55 cm ± 5.4SE. Guinea grass thatch was reduced by cattle grazing, likely through consumption and trampling, indirectly benefiting native plants. Precipitation and grazing together enhanced Shannon diversity more than either factor alone. For example, at 300 mm of rain and 50% tiller grazing, Shannon diversity increased by 40% (from 0.46 to 0.65 ± 0.14SE). This effect may be due to Guinea grass's resource competition and thatch production. Higher precipitation required more cattle to achieve 50% tillers grazed during wetter survey periods, as measured by camera traps. In contrast, grazing was effective during dry seasons when Guinea grass was likely water-stressed. A Canonical Correlation Analysis differentiated Guinea grass from the rest of the grassland plant community, revealing positive and negative associations with key species: <em>Prosopis glandulosa</em> (CCA1 = 0.0511) and <em>Ambrosia psilostachya</em> (CCA1 = –0.0514). Our findings suggest that targeted grazing and monitoring precipitation patterns can effectively manage Guinea grass and promote native plant diversity in invaded rangelands.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 495-506"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145568404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Herbicide Applications in California Dryland Perennial Grasses Improve Forage Yield and Crop Coverage","authors":"Josh Davy ,&nbsp;Ryan Hill ,&nbsp;Larry Forero","doi":"10.1016/j.rama.2025.07.009","DOIUrl":"10.1016/j.rama.2025.07.009","url":null,"abstract":"<div><div>Summer dormant perennial grasses in the annual rangelands of California’s foothills must be managed to maintain productivity. Weed invasion can reduce forage quality and stand persistence and information is lacking on best practices for weed management. Trials were established to assess the effects of indaziflam, rimsulfuron, and aminopyralid herbicides on nine perennial grass species. Herbicide treatments were applied seven years after planting and effects on crop coverage and forage biomass production were evaluated for two growing seasons. Treatment effects on weed populations, perennial grass coverage, and forage biomass varied by planted species. Generally, medusahead invasion was promoted by rimsulfuron treatments, yellow star-thistle was only abundant in the unplanted control, and hare barley was reduced by aminopyralid and indaziflam treatments. The lowest perennial grass coverage was typically observed in the untreated control and the lowest biomass was typically associated with indaziflam treatments. Coverage of wheatgrass and orchard grass varieties was improved by indaziflam treatments. Coverage of Harding grass varieties tended to be greatest in plots treated with rimsulfuron and the highest overall biomass and coverage was achieved in \"Perla\" koleagrass treated with 70 g ai ha^-1 rimsulfuron. Aminopyralid treatments resulted in variable crop coverage effects, but often improved forage biomass through promotion of annual ryegrass.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 78-82"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144879690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free-Roaming Horse Diet and Body Condition Differences Across Seasons and Ecologically Diverse Herd Management Areas","authors":"Courtney E. Buchanan ,&nbsp;Stephanie J. Galla ,&nbsp;Jared Studyvin ,&nbsp;Jonathan D. Lautenbach ,&nbsp;John Derek Scasta ,&nbsp;Gregory D. Randolph ,&nbsp;Jennifer S. Forbey ,&nbsp;Jeffrey L. Beck","doi":"10.1016/j.rama.2025.08.001","DOIUrl":"10.1016/j.rama.2025.08.001","url":null,"abstract":"<div><div>Increasing populations of free-roaming horses (<em>Equus caballus</em>) residing on federal lands pose management challenges across the American West, affecting rangeland health and co-occurring wildlife and livestock species. To better understand how free-roaming horses interact with rangeland ecosystems through herbivory, we used amplicon sequencing (P6 loop of chloroplast <em>trnL</em>) of horse fecal material to quantify plant composition of diets across a gradient of herbaceous availability in 16 Herd Management Areas (HMAs) managed by the Bureau of Land Management. These HMAs encompassed several ecosystems, including the Colorado Plateau, Great Basin, Mojave Desert, and Wyoming Basin. We collected 1,409 visual body condition scores (BCS) (on a 1-to-9 scale) and 465 individual fecal collections in summer 2020 and winter 2020/2021 across HMAs. Because horses are considered grazers, we explored whether the dietary proportion of graminoids (i.e., grasses and grass-like plants) changed seasonally between and among HMAs. The proportion of graminoids in fecal material differed by HMA and ranged from 31.17% to 83.50% in summer and 11.00% to 82.60% in winter. Summer diets trended toward higher graminoid composition in most HMAs, and many winter diets shifted to include nongraminoid plants in the Asteraceae and Chenopodiaceae families. Despite varying dietary graminoid composition, herd average BCS indicated most free-roaming horses were in good condition. Across HMAs, herd average BCS in summer averaged 5.01 (minimum 4.59 and maximum 5.24) and averaged 4.98 in winter (minimum 4.72 and maximum 5.22). Understanding which plant groups form seasonal diets of free-roaming horses across different environments is important for managers balancing potential forage competition among free-roaming horses, wildlife, and livestock. Our results indicate that while free-roaming horses are considered grazers, they are also capable of subsisting and maintaining good body condition while consuming a variety of plants, with graminoids not always forming the majority of the diet.</div></div>","PeriodicalId":49634,"journal":{"name":"Rangeland Ecology & Management","volume":"103 ","pages":"Pages 230-246"},"PeriodicalIF":2.4,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}