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Rangeland carbon is often conceptualized similarly to intensively managed agricultural lands, in that we need to sequester and store more carbon. Unlike intensively managed agricultural lands, rangeland soils cannot sequester more carbon due to pedogenic and climatic limitations that influence plant community and microbial community dynamics. This requires a new paradigm for rangeland carbon that focuses on maintaining carbon security following disturbances like fire and plant community conversions (e.g., annual grasslands and conifer woodlands). To attain this, we propose the creation of a Carbon Security Index (CSI). CSI is a unitless, scalable value that can be used to compare carbon security across rangeland sites and over time and incorporates a plant fractional cover ratio, resistance and resilience, and wildfire probability. Using the Great Basin as a case study, we found that CSI decreased by 53% basin wide from 1989 to 2020. Using the Sagebrush Conservation Design's sagebrush ecological integrity categories across the Great Basin, we found that CSI in “core” areas remained relatively unchanged between 1998 and 2020 (decreased by 1%), whereas “growth opportunity” areas CSI began to change (decreased by 13%) and “other rangeland” areas CSI decreased by 67%. We found that CSI was able to act as an indicator for determining when carbon security would decrease several years prior to a wildfire disturbance, which then rapidly reduced CSI. Finally, we created a carbon security management map to help prioritize potential management for achieving greatest carbon security and locations for restoration. These results show that CSI provides landowners and land managers an opportunity to assess how secure their carbon is on the land and help them prioritize areas for restoration.

Understanding how climate change will contribute to ongoing declines in sagebrush ecological integrity is critical for informing natural resource management, yet complicated by interactions with wildfire and biological invasions. We assessed potential future changes in sagebrush ecological integrity under a range of scenarios using an individual plant-based simulation model, integrated with remotely sensed estimates of current sagebrush ecological integrity. The simulation model allowed us to estimate how climate change, wildfire, and invasive annuals interact to alter the potential abundance of key plant functional types that influence sagebrush ecological integrity: sagebrush, perennial grasses, and annual grasses. Our results suggest that climate driven reductions in sagebrush ecological integrity may occur over broader areas than increases in sagebrush ecological integrity. Declines in sagebrush ecological integrity were most likely in hot and dry regions while increases were more likely in cool and wet regions. The most common projected transitions of sagebrush ecological integrity classes were declines from Core Sagebrush Area to Growth Opportunity Area and from Growth Opportunity Area to Other Rangeland Area. Responses varied considerably across projections from different global climate models, highlighting the importance of climate uncertainty. However, our projections tended to be robust in areas that currently have the highest sagebrush ecological integrity. Our results provide a long-term perspective on the vulnerability of sagebrush ecosystems to climate change and may inform geographic prioritization of conservation and restoration investments. The results also suggest that ongoing threats, such as the continued invasion by annual grasses and increased wildfire frequency, are likely to be amplified by climate change, and imply that the current imbalance between capacity for conservation to address threats to sagebrush will grow as the climate warms.

In the last 20 years, the North American sagebrush biome has lost over 500 000 ha of intact and largely intact sagebrush plant communities on an annual basis. Much of this loss has been associated with expansion and infilling of invasive annual grasses (IAGs). These species are highly competitive against native perennial grasses in disturbed environments, and create fuel conditions that increase both the likelihood of fire ignition and the ease of wildfire spread across large landscapes. Given the current rate of IAG expansion in both burned and unburned rangelands, we propose a range-wide paradigm shift from opportunistic and reactive management, to a framework that spatially prioritizes maintenance of largely intact, uninvaded areas and improvement of invaded habitats in strategic locations. We created a framework accompanied by biome-wide priority maps using geospatial overlays that target areas to MAINTAINlarge, uninvaded areas as natural resource anchors through activities to prevent IAGs, IMPROVEareas where management success in restoring large, intact landscapes is most likely, and CONTAINIAG infestations where necessary. We then offer three case studies to illustrate the use of these concepts and map products at multiple scales. Our map products operate at the biome scale using regional data sources and additional data sources will be needed to inform local conservation planning. However, the basic strategic management principles of (1) maintaining the intact and uninvaded areas that we can least afford to lose to IAGs, (2) improving areas where we have a reasonable likelihood of restoration success, and (3) containing problems where we must, are timely, relevant, and scalable from the biome to local levels.

Invasive annual grasses, such as medusahead (Taeniatherum caput-medusae[L.] Nevski), have invaded tens of millions of hectares of the sagebrush ecosystem. These invasions severely reduce ecosystem goods and services provided, as well as increase the probability of frequent, large wildfires. Revegetation of invasive annual grass−invaded rangeland with perennial bunchgrasses is critical to reversing these negative consequences. Short-term evaluations of revegetation efforts have shown promising results. However, long-term evaluations of revegetation efforts in medusahead-invaded rangelands are lacking, so it remains unknown if revegetation attempts in these invaded rangelands have persistent effects. We evaluated the effects of controlling medusahead with prescribed burning and imazapic application followed 1 yr later with drill-seeding large perennial bunchgrasses at two seeding rates (medium and high) for more than a decade post seeding. Large perennial bunchgrass cover and density was > 16- and > 4-fold greater in revegetation treatments compared with the untreated control 11 yr after seeding, respectively. Invasive annual grass abundance was ∼twofold greater in the untreated control compared with the revegetation treatments. These results suggest that revegetation efforts in medusahead-invaded rangelands can have persistent ecological benefits (increased perennials and decreased invasive annuals). The high seeding rate resulted in more perennial bunchgrass and less invasive annual grass compared with the medium seeding rate over the duration of the study, suggesting that high seeding rates may be needed to maximize benefits. Revegetation of medusahead-invaded rangelands can have long-lasting effects, though high establishment of perennial bunchgrasses is likely necessary for success.

Wyoming big sagebrush (Artemisia tridentataNutt. ssp. wyomingensis[Beetle & A. Young] S. L. Welsh) has decreased from its historic prevalence across the sagebrush steppe in part because of its interaction with invasive annual grasses and the increased wildfire frequency. Restoration of this species is vital to the ecosystem; however, traditional seeding methods such as broadcast or drill seeding have low success rates. Seedling mortality is associated with harsh weather conditions such as freezing temperatures in the winter and extreme temperature and soil moisture conditions during the summer drought. Transplanting sagebrush has greater success by overcoming the bottleneck of early seedling mortality. We tested how sagebrush transplant survival and size (canopy volume) are affected by age at the time of planting (10 classes, 6−24 wk), planting season (fall versus spring), and invasive annual grass competition (low/high) with a randomized factorial design over 2 yr. Survival was lower for age classes under 10 or 12 wk (in yr 1 and 2, respectively) but relatively similar from 12 to 24 wk. Fall-planted transplants had lower survival but increased canopy volume compared with spring-planted transplants. Survival and canopy volume decreased with competition with annual grasses. Our results suggest that land managers should consider planting younger transplants than previously thought and controlling invasive annual grasses before planting sagebrush transplants to increase long-term survival and canopy volume.

The invasive annual grass, medusahead, infests rangelands throughout the West, from the Columbia Plateau to the California Annual Grasslands and the Great Basin. Dominating secondary succession in the sagebrush steppe, medusahead can degrade the habitat of threatened species such as the greater sage-grouse. This research explores the potential of dormant season grazing as an applied management strategy to reduce the negative impacts of medusahead while promoting recovery of perennial vegetation at the landscape scale. In particular, it assessed grazing with four treatments from 2018 to 2020: traditional grazing (May–October), dormant season grazing (October–February), traditional + dormant season grazing (May–February), and no grazing. After 2 yr of grazing treatments, biomass, density, cover, and fuel continuity did not differ between treatments (P> 0.05). However, biomass measurements were significantly different between years, which is likely due to greater than normal precipitation in 2019 and 2020. Between 2018 and 2019, annual grass biomass increased by 81% (666–1 212 kg ha−1) and perennial grass biomass increased by 165% (118–313 kg ha−1). Litter biomass decreased by approximately 15% in every year since 2018 (2 374, 2 012, and 1 678 kg ha−1in 2018–2020). There were not significant differences in cover or density of annual and perennial grasses between treatments and years. Our results indicate that 2 yr may not be adequate time for dormant season grazing treatments to be effective in reducing the abundance of medusahead and that after 2 yr of treatments, dormant season grazing does not have a detrimental effect on perennial vegetation.

Spatial and temporal dynamics of rangeland fuels is a primary factor driving large wildfires. Yet detailed information capturing variation in fine fuels has largely been missing from rangeland fire planning and fuels management. New fuels-based maps of Great Basin rangeland fire probability help bridge this gap by coupling dynamic vegetation cover and production data from the Rangeland Analysis Platform with weather and climate data to provide annual forecasts of the relative probability of large wildfire. In this paper, we review these new fuels-based maps and discuss implications for prefire planning, preparedness, and strategic fuels management. Examining patterns of fire probability through time reveals high spatial and temporal variation in risk of large wildfires across the Great Basin. Certain areas are chronically impacted with high fire probability most years, while others have more sporadic or low probability of large fire annually. Maps confirm previous research that the recent increase in large fire risk in the region is highly associated with invasive annual grasses, but total aboveground herbaceous production (including perennials) continues to be a primary predictor of fire probability. Fuels-based fire probability maps can be used alongside existing data sources and prioritization frameworks by fire and fuels managers to inform questions of 1) what kind of fire year might this be, 2) where large fires are most likely to occur given an ignition, and 3) where resources should be focused. We provide examples of how maps can be used to improve prefire preparedness and planning to enhance suppression, facilitate annual targeting of fine fuels reductions, and support land use planning for implementation of landscape-scale fuels management. Proactively incorporating this new information into rangeland fire and fuels management can help address altered fire regimes threatening the region's wildlife and working lands.

Wildfires are increasingly impacting ecosystem processes and ecological services provided by sagebrush rangelands in the western United States. Mitigating this problem involves actions taken before, during, and after fire. In recent years, there has been increased emphasis on prefire fuel management, including fuel breaks. Cattle grazing can be used as a tool to manage fine fuel loading within fuel breaks; however, spatially focusing grazing impacts inside a linear fuel break is challenging. We evaluated using virtual fencing (VF) technology for concentrating grazing impacts inside a 200-m wide, 3-km long fuel break within a 410-ha pasture in sagebrush steppe. The fuel break was bounded by four 35-m wide virtual fences, each consisting of boundaries for auditory (10-m wide) and electrical cues (25-m wide), and a traditional 5-strand barbed wire perimeter fence delineated the pasture perimeter. In June 2021 we introduced 16 dry cows and 23 cow/calf pairs into the fuel break following a 5-d VF training period; cattle were removed after 30 d. Cows were fitted with VF collars (calves not collared) that use Global Positioning System positioning to contain cattle inside fuel break boundaries and record animal locations at 5-min intervals. End-of-trial forage utilization was 48.5% ± 3.7% and 5.5% ± 0.7% for areas inside and outside of the fuel break, respectively. Daily percentage of cattle locations inside the fuel break was initially > 94% but declined to approximately 75% by the end of the trial. Percentage daily locations of dry cows and cow/calf pairs inside the fuel break was 98.5% ± 0.5% and 80.6% ± 1.1%, respectively (P< 0.001). Our data suggest virtual fencing can be a highly effective method of concentrating grazing to reduce herbaceous fuel biomass within linear fuel breaks. Efficacy of this method could be substantially impacted by use of dry versus cow/calf pairs.

Wildfires are a growing management concern in western US rangelands, where invasive annual grasses have altered fire regimes and contributed to an increased incidence of catastrophic large wildfires. Fire activity in arid, nonforested ecosystems is thought to be largely controlled by interannual variation in fuel amount, which in turn is controlled by antecedent weather. Thus, long-range forecasting of fire activity in rangelands should be feasible given annual estimates of fuel quantity. Using a 32-yr time series of spatial data, we employed machine learning algorithms to predict the relative probability of large (> 405 ha) wildfire in the Great Basin based on fine-scale annual and 16-d estimates of cover and production of vegetation functional groups, weather, and multitemporal scale drought indices. We evaluated the predictive utility of these models with a leave-1-yr-out cross-validation, building spatial hindcasts of fire probability for each year that we compared against actual footprints of large wildfires. Herbaceous aboveground biomass production, bare ground cover, and long-term drought indices were the most important predictors of burning. Across 32 fire seasons, 88% of the area burned in large wildfires coincided with the upper 3 deciles of predicted fire probabilities. At the scale of the Great Basin, several metrics of fire activity were moderately to strongly correlated with average fire probability, including total area burned in large wildfires, number of large wildfires, and maximum fire size. Our findings show that recent years of exceptional fire activity in the Great Basin were predictable based on antecedent weather-driven growth of fine fuels and reveal a significant increasing trend in fire probability over the past 3 decades driven by widespread changes in fine fuel characteristics.

Exotic annual grass invasion is a pressing concern in sagebrush rangelands of the western United States. Overgrazing and fire have historically both been implicated in the rise of annual grasses, but experiments that compare the effect of grazing versus fire are lacking, particularly for contemporary grazing practices such as off-season (fall and winter) grazing. We compared 1) burned and ungrazed (burned), 2) off-season, moderately grazed and unburned (grazed), and 3) ungrazed and unburned (control) treatments at five Wyoming big sagebrush (Artemisia tridentatassp. wyomingensis[Beetle & A. Young] S.L. Welsh) sites in southeastern Oregon for half a decade. Fire, but not off-season grazing, substantially increased exotic annual grass cover and abundance. Vegetation cover and density were generally similar between grazed and control areas. In contrast, at the end of the study exotic annual grass cover and density were over fourfold greater in burned areas. Exotic annual grass became the dominant plant group in burned areas, but not in grazed and control areas. Cover and density of annual forbs, predominately non-native species, were generally greater in the burned compared with grazed and control treatments. Fire also decreased soil biological crust cover and sagebrush cover and density compared with grazed and control treatments. This study provides strong evidence that fire is a threat to the sustainability of Wyoming big sagebrush communities at risk of exotic annual grass dominance, but that off-season, moderate grazing poses little risk. However, considering the spatial extent of our study was limited, further evaluations are needed across a larger geographic area. Given that off-season grazing can decrease the probability of fire, off-season grazing may be a valuable tool to reduce the risk of exotic annual grass dominance.

On public lands grazing allotments in the western US sagebrush steppe, cattle are generally excluded from burned pastures for 2 yr post fire. If only a portion of a pasture burns, the burned area may be fenced, allowing for cattle grazing to resume in the unburned portion. However, traditional wire-based fencing is often not an option due to expense, conflicts with wildlife management objectives, and extensive procedural logistics. We evaluated the use of a “virtual fence” (VF) for excluding cattle from burned areas within small pastures in the sagebrush steppe of southeast Oregon. VF technology (Vence Corporation, San Francisco, CA) uses satellite-controlled collars that direct animal movement within user-defined polygons using auditory and electrical cues. We fall-burned a 0.6-ha area in each of six adjacent 2.1-ha pastures in a Wyoming big sagebrush plant community in 2019. In June 2020, each pasture was stocked with 3 mature dry cows for 14 d. All cows were fitted with VF collars; collars were programed to create a virtual fence around the burned area within three of the pastures (VF treatment), and remaining pastures had electrical and auditory cues turned off (control treatment). Collars recorded animal location every 5 min. Cows in the control treatment initially spent up to 40% of their time within the burned area, and forage utilization of the burned area was nearly 70%. Cows in the VF treatment spent approximately 4% of their time in the burned area on day 1 and were recorded in the burn only incidentally thereafter; forage utilization in the burn was < 3%. Our trial suggests VF technology is effective in controlling rangeland cattle movements and can severely curtail use of burned areas. Additional work is needed to evaluate VF technology in larger rangeland settings.

Invasive annual grasses such as cheatgrass (Bromus tectorumL.) outcompete native grasses, increase fire frequency, and impact the functionality and productivity of rangeland ecosystems. Preemergent herbicide treatments are often used to control annual grasses but may limit timely restoration options due to negative effects on concurrently planted desired seeded species. We tested the efficacy of activated carbon-based herbicide protection coatings applied to individual bluebunch wheatgrass (Pseudoroegneria spicata[Pursh] A. Love) seeds for protecting seedlings from injury associated with pre-emergent herbicide (imazapic) application in a laboratory environment. Emergence of coated seed averaged 57% ± 5% compared with bare seed, which had 14% ± 10% emergence with imazapic application. Seedling height for coated seed averaged 7.56 ± 0.6 cm compared with 2.26 ± 0.4 cm in uncoated bare seed in the presence of imazapic. Coated seeds produced 87% more plant biomass than uncoated seeds. Our laboratory results suggest that treating individual seeds with an activated carbon-based coating dramatically reduces negative effects of pre-emergent herbicide on desired seeded species. Field studies are needed to confirm these results in an applied restoration context.

Restoration of non-sprouting shrubs after wildfire is increasingly becoming a management priority. In the western U.S., Wyoming big sagebrush (Artemisia tridentataNutt. ssp. wyomingensisBeetle & Young) restoration is a high priority, but sagebrush establishment from seed is sporadic. In contrast, planting seedlings often successfully restores sagebrush, but is expensive and time consuming. After planting, hence, there is a need to protect the investment from disturbances such as fire that will erase gains in sagebrush recovery. Grazing is likely the only tool that can be applied feasibly across the landscape to decrease wildfire probability, but there are concerns that grazing and associated activities (e.g. trampling) may negatively impact sagebrush seedlings. We investigated effects of grazing by cattle, applied as a fine fuel management strategy, on planted sagebrush seedlings at five blocks for five years. Grazing substantial reduced exotic annual grasses, large perennial bunchgrasses, and total herbaceous cover, thus achieving fuel management goals. Sagebrush cover and reproductive efforts were almost 2-fold greater in grazed compared to non-grazed areas in the final year of the study. This suggests that grazing favored sagebrush, a generally unpalatable shrub, recovery, likely by reducing competition from highly palatable herbaceous vegetation. Density of sagebrush, however, was similar between grazed and non-grazed areas. This research demonstrates that grazing can be strategically applied to reduce the probability of wildfire in areas with planted sagebrush seedlings; thereby, protecting the investment in sagebrush recovery. With more refinement, it also appears that grazing can be utilized to accelerate the recovery of sagebrush and potentially other woody vegetation habitat by modifying the competitive relationship between herbaceous and woody vegetation.

Sage‐grouse (Centrocercusspp.) are influencing rapidly evolving land management policy in the western United States. Management objectives for fine‐scale vegetation characteristics (e.g., grass height >18 cm) have been adopted by land management agencies based on resource selection or relationships with fitness proxies reported among numerous habitat studies. Some managers, however, have questioned the appropriateness of these objectives. Moreover, it remains untested whether habitat–fitness relationships documented at fine scales (i.e., among individual nests within a study area) also apply at scales of management units (e.g., pastures or grazing allotments), which are many orders of magnitude larger. We employed meta‐analyses of studies published from 1991 to 2019 to help resolve the role of fine‐scale vegetation structure in nest site selection and nest success across the geographic range of greater sage‐grouse (C. urophasianus) and evaluate the validity of established habitat management objectives. Specifically, we incorporated effects of study design and functional responses to resource availability in meta‐regression models linking vegetation structure to nest site selection, and used a novel meta‐analytic approach to simultaneously model vegetation structure and its relationship to nest success. Our approach tested habitat relationships at a range‐wide extent and a grain size closely matching scales at which agencies make management decisions. We found moderate, but context‐dependent, effects of shrub characteristics and weak effects of herbaceous vegetation on nest site selection. None of the tested vegetation characteristics were related to variation in nest success, suggesting nesting habitat–fitness relationships have been inappropriately extrapolated in developing range‐wide habitat management objectives. Our findings reveal surprising flexibility in habitat use for a species often depicted as having very particular fine‐scale habitat requirements, and cast doubt on the practice of adopting precise management objectives for vegetation structure based on findings of individual small‐scale field studies. © 2020 The Authors. The Journal of Wildlife Managementpublished by Wiley Periodicals, Inc. on behalf of The Wildlife Society. Sage‐grouse offer an illustrative case of a common situation in which management objectives, based on informal synthesis of findings of small‐scale field studies, are applied across a species' range. Our meta‐analyses of sage‐grouse nesting studies revealed that widely adopted habitat management objectives prescribe a narrow range of conditions found in only a small subset of breeding habitats successfully exploited by the species across its range, and have no relationship to demographic performance.

Rangelands in the western United States exhibit extremely high temporal variability in seedbed microclimate, and this variability contributes to poor establishment of revegetation species that are typically planted in the fall. We conducted long-term simulations of cumulative germination as a function of planting date and identified alternative germination syndromes based on population-level responses to environmental variability. These germination syndromes reveal ecologically significant differences but also noteworthy similarities in species and seed lot response that can inform rangeland restoration planning and management. Seed germination may occur much sooner than assumed under the traditional paradigm of fall-planting/spring-emergence in the intermountain western United States, and seed germination per se does not appear to be a bottleneck for successful establishment in most years. Instead, simulations of germination response support recent hypotheses that postgermination/preemergent mortality may be the larger contributor to poor seedling establishment. Our data support two general strategies to improve the likelihood of seedling survival into the spring: seeding as late as possible in the fall and active diversification of germination syndromes within a given seed mix. Consistent application of these strategies could increase the probability that some seeds are always available to take advantage of any pulse of seedbed favorability in the late fall, winter, or early spring.

Crested wheatgrass (Agropyron cristatum[L] Gaertm. and Agropyron desertorum[Fisch.] Schult.), an introduced bunchgrass, has been seeded on millions of hectares of sagebrush steppe. It can establish near-monocultures; therefore, reestablishing native vegetation in these communities is often a restoration goal. Efforts to restore native vegetation assemblages by controlling crested wheatgrass and seeding diverse species mixes have largely failed. Restoring sagebrush, largely through planting seedlings, has shown promise in short-term studies but has not been evaluated over longer timeframes. We investigated the reestablishment of Wyoming big sagebrush (Artemisia tridentataspp. wyomingensis[Beetle & A. Young] S.L. Welsh) in crested wheatgrass communities, where it had been broadcast seeded (seeded) or planted as seedlings (planted) across varying levels of crested wheatgrass control with a herbicide (glyphosate) for up to 9 yr post seeding/planting. Planting sagebrush seedlings in crested wheatgrass stands resulted in full recovery of sagebrush density and increasing sagebrush cover over time. Broadcast seeding failed to establish any sagebrush, except at the highest levels of crested wheatgrass control. Reducing crested wheatgrass did not influence density, cover, or size of sagebrush in the planted treatment, and therefore, crested wheatgrass control is probably unnecessary when using sagebrush seedlings. Herbaceous cover and density were generally less in the planted treatment, probably as a result of increased competition from sagebrush. This trade-off between sagebrush and herbaceous vegetation should be considered when developing plans for restoring sagebrush steppe. Our results suggest that planting sagebrush seedlings can increase the compositional and structural diversity in near-monocultures of crested wheatgrass and thereby improve habitat for sagebrush-associated wildlife. Planting native shrub seedlings may be a method to increase diversity in other monotypic stands of introduced grasses.

Invasive annual grasses threaten the ecological integrity of the sagebrush ecosystem, often increasing when wildfires or other disturbances reduce perennial vegetation. In response to this threat, perennial bunchgrasses are often seeded after wildfire. Because of greater success in establishment, introduced bunchgrasses are often selected for seeding instead of commercially available native bunchgrasses. However, locally sourced native bunchgrasses appear to establish better than generally expected for commercially available native bunchgrasses but introduced bunchgrasses still establish better and result in greater suppression of invasive annual grasses. In areas where native bunchgrasses have been established from seeding but annual grass abundance remains high, selective control of annual grasses may improve success. Comparisons between areas where locally sourced native and introduced bunchgrasses were seeded and established, followed by annual grass control, are lacking. We investigated vegetation characteristics in areas drill-seeded with introduced compared with locally sourced native bunchgrasses after a wildfire that received selective annual grass control (imazapic application) 3 yr after seeding. Treatments that were seeded with locally sourced native or introduced bunchgrasses followed by spraying imazapic increased bunchgrass cover and density compared with areas not seeded but sprayed with imazapic. Bunchgrass cover and density were greater in areas seeded with introduced compared with native bunchgrasses and sprayed with imazapic. Invasive annual grass abundance was reduced with seeding introduced bunchgrasses followed with imazapic application, but not with seeding locally sourced native bunchgrasses followed with spraying imazapic. These results suggest that locally sourced native bunchgrasses have the potential for restoration success, but research needs to determine what follow-up treatments (e.g., additional seeding, longer-term annual grass control, and more diverse seed mixes) are needed to further promote perennial vegetation abundance and increase resistance to annual grasses to achieve similar outcomes as seeding introduced bunchgrasses.

Plant communities in a stable, long-term state with high sagebrush cover and low desirable perennial herbaceous cover and/or relatively high invasive annual cover, are widespread across the Great Basin and distinct from areas affected by wildfire. Restoring these areas, collectively called ‘degraded sagebrush understories’ and preventing future degradation is a management challenge that requires maintaining desirable levels of sagebrush cover while simultaneously increasing understory perennial abundance and diversity. Defining degradation based on a firm grasp of current and potential vegetation composition is a fundamental aspect of setting restoration goals and selecting methods. Assigning degraded status to any given site is also a considerable challenge in many sagebrush landscapes due to widespread (and long-standing) lack of intact herbaceous plant communities in some landscapes as well as high interannual variation in herbaceous community composition (particularly cover). In this manuscript, we provide a workflow for defining degraded understories and present a framework for identifying restoration approaches emphasizing the pathways (causes) of degradation in this system, such as historical cultivation, inappropriate grazing, invasive species, and drought, as well as the size and extent of degraded areas. We also describe the relative paucity of well-documented successful restoration approaches for degraded understories, particularly for one-time restoration treatments. This lack of success may be due to lack of propagules, potential competition from sagebrush, invasive species, and/or altered soil conditions. Multiple restoration treatments in specific sequences and/or years may increase success, however the effectiveness of these techniques is uncertain due to infrequent implementation and rigorous evaluation across a range of environmental conditions. Due to the extent of degraded understories in Great Basin sagebrush ecosystems, meeting biome-level conservation goals will likely require additional research to characterize the types and development pathways of the degraded understories, spatiotemporal recovery or ongoing degradation patterns, and targeted restoration techniques.

Livestock grazing is the primary land use across sagebrush ecosystems in the western US and its effects have been subject to extensive research and debate. Historical overgrazing, annual grass invasion and associated increase in fire frequency, conifer encroachment, climate change, and human modification have resulted in the loss or degradation of 86% of sagebrush ecosystems, leading to intensified interest in how remaining intact rangelands are managed. Unlike historical, continuous grazing, contemporary practices generally incorporate planned periods of rest and recovery from grazing during the growing season. Dormant season grazing is one such practice that shows promise for improving degraded rangelands and reducing wildfire risk. However, no studies have compared moderate intensity dormant season grazing to contemporary spring-summer grazing and grazing exclusion in sagebrush rangelands dominated by perennial bunchgrasses. We evaluated the effects of contemporary spring-summer grazing, dormant season grazing, and grazing exclusion on plant community characteristics in a Wyoming big sagebrush ecosystem. We expected the effects of dormant season grazing to be comparable to grazing exclusion. Deep-rooted perennial bunchgrass cover and density and shallow-rooted perennial bunchgrass cover in grazed areas did not differ from grazing exclusion (control) sites, and we found no support that grazing altered the deep-rooted perennial bunchgrass community through time. Dormant season grazing reduced native annual forb and sagebrush cover, but increased density of the shallow-rooted perennial bunchgrass. Our results suggest contemporary spring-summer or dormant season grazing are unlikely to lead to a decline in desirable perennial bunchgrasses.

Rangelands around the globe are experiencing management challenges associated with existing and emerging stressors, including more frequent and severe fires, woody species expansion, annual grass invasion, heavy, repeated growing season grazing, and climate change. Disturbance is an essential part of rangeland systems. Yet climate change is likely to affect rangelands most directly by increasing the likelihood, severity, and extent of long-term, negative impacts from disturbance. We conducted a synthesis of key vulnerabilities to climate change for Northwest USA rangelands. These rangelands are projected to become warmer and drier this century, with episodes of more extreme droughts and higher likelihood of more severe fires affecting larger areas. Many of the vulnerabilities identified in our synthesis, such as increased frequency of fire and invasive grass proliferation, can have lasting effects, leading to “undesirable transformations” (substantial and persistent changes in vegetation composition and reductions in ecosystem services). For example, larger, more severe fires have led to the rapid loss of critical Greater sage-grouse habitat and diminished forage production capacity for livestock in some areas, lowering provisioning of ecosystem services, increasing fire management costs, and impacting rural livelihoods. Rangeland managers need guidance connecting climate change projections to on-the-ground management actions. We conclude from our synthesis of climate change vulnerabilities that supporting rangeland recovery is an important climate adaptation approach on Northwest rangelands. Proactive climate adaptation strategies (e.g., supporting soil health and vegetation) and example practices (e.g., establishing climate-adapted perennial plant species) are presented according to key action areas: prepare for, respond to, and recover from disturbance. Identifying specific adaptation needs at more local scales, like the management unit level, may be further refined through proactive planning and experimentation in collaborative settings that allow for resource pooling and foster learning.

Seeding crested wheatgrass (Agropyron desertorum[Fisch.] Schult.) in the sagebrush steppe is a controversial management action. There are concerns that crested wheatgrass may invade new areas and exclude native vegetation because many former crested wheatgrass seedings are near monocultures. However, crested wheatgrass is often seeded to prevent exotic annual grass invasion and stabilize soils after disturbances in areas where native vegetation is unlikely to establish. These areas can be difficult to identify and, consequentially, crested wheatgrass may be seeded in areas it is not needed, such as sagebrush steppe with understories dominated by native perennial grasses and forbs (intact understories). Thus, land managers need to know the potential effects of seeding crested wheatgrass, especially if it can invade and exclude native vegetation in sagebrush steppe with intact understories. We investigated the ability of crested wheatgrass to invade and exclude native vegetation by drill seeding crested wheatgrass into intact sagebrush steppe understories at five sites. To be invasive, crested wheatgrass would need to increase in abundance beyond initial establishment from drill seeding, causing decreases in native vegetation. We measured vegetation cover and density for 7 yr after seeding to evaluate the effects of seeding crested wheatgrass. Crested wheatgrass established with drill seeding but did not increase from its original density. Cover of crested wheatgrass increased with time but was < 2% seven yr after seeding. We found no evidence that seeding crested wheatgrass decreased the cover or abundance of native vegetation. These results suggest that intact sagebrush steppe understories are competitive with crested wheatgrass and, thereby, limit its recruitment and growth. Though crested wheatgrass did not show indications of being invasive in intact sagebrush steppe understories, longer-term evaluations with the inclusion of disturbances that might open safe sites in these communities would be prudent to fully understand its potential effects.

Grazing by cattle is ubiquitous across the sagebrush steppe; however, little is known about its effects on sagebrush and native bunchgrass structure. Understanding the effects of long-term grazing on sagebrush and bunchgrass structure is important because sagebrush is a keystone species and bunchgrasses are the dominant herbaceous functional group in these communities. To investigate the effects of long-term grazing on sagebrush and bunchgrass structure, we compared nine grazing exclosures with nine adjacent rangelands that were grazed by cattle in southeast Oregon. Grazing was moderate utilization (30−45%) with altering season of use and infrequent rest. Long-term grazing by cattle altered some structural aspects of bunchgrasses and sagebrush. Ungrazed bunchgrasses had larger dead centers in their crowns, as well as greater dead fuel depths below and above the crown level compared with grazed bunchgrasses. This accumulation of dry fuel near the meristematic tissue may increase the probability of fire-induced mortality during a wildfire. Bunchgrasses in the ungrazed treatment had more reproductive stems than those in the long-term grazed treatment. This suggests that seed production of bunchgrasses may be greater in ungrazed areas. Sagebrush height and longest canopy diameter were 15% and 20% greater in the ungrazed compared with the grazed treatment, respectively. However, the bottom of the sagebrush canopy was closer to the ground in the grazed compared with the ungrazed treatment, which may provide better hiding cover for ground-nesting avian species. Sagebrush basal stem diameter, number of stems, amount of dead material in the canopy, canopy gap size, and number of canopy gaps did not differ between ungrazed and grazed treatments. Moderate grazing does not appear to alter the competitive relationship between a generally unpalatable shrub and palatable bunchgrasses. Long-term, moderate grazing appears to have minimal effects to the structure of bunchgrasses and sagebrush, other than reducing the risk of bunchgrass mortality during a fire event.

Perennial bunchgrasses are critical to maintaining sagebrush plant communities, but seeding of native bunchgrasses following fire has had limited success. Previous research indicated that blackened soils beneath burned sagebrush canopies have increased bunchgrass seeding success when compared with interspace locations. We investigated soil moisture and temperature across white, neutral, and black soils and tested the relationship between soil color and seedling demographics for bluebunch wheatgrass. We used a randomized block design with three treatments and five replications conducted in a Wyoming big sagebrush community in southeast Oregon. The study site was rototilled before establishing 50 x 50 cm plots in each of 2 yr. We installed soil temperature/moisture probes at 3-cm depth in each plot. Plots were seeded in November of each year with 125 viable seeds and covered in a <1-mm layer of white, brown, or black aquarium sand. We counted emergent seedlings weekly through May of the year following planting. Soil moisture during the emergence period (March–May) was highest for white soils and lowest for black or neutral soils (P<0.001); soil temperature was highest for black or neutral soils and lowest for white soils (P<0.001). Year 1 was characterized by a relatively warm and dry emergence period, and year 2 was relatively cool and moist. Emergent seedling density was highest (P<0.05) for white soils; surviving seedling density (on June 1) was highest (P<0.05) for white soils in year 1 and black soils in year 2. Black soils had greater success in a year with lower soil temperatures and adequate soil moisture. When soil moisture was limited, and spring temperatures warmer, increased soil temperature on black soils led to seedling desiccation and death.

Conservation of imperiled species often demands addressing a complex suite of threats that undermine species viability. Regulatory approaches, such as the US Endangered Species Act (1973), tend to focus on anthropogenic threats through adoption of policies and regulatory mechanisms. However, persistent ecosystem-based threats, such as invasive species and altered disturbance regimes, remain critical issues for most at-risk species considered to be conservation-reliant. We describe an approach for addressing persistent ecosystem threats to at-risk species based on ecological resilience and resistance concepts that is currently being used to conserve greater sage-grouse (Centrocercus urophasianus)and sagebrush ecosystems. The approach links biophysical indicators of ecosystem resilience and resistance with species-specific population and habitat requisites in a risk-based framework to identify priority areas for management and guide allocation of resources to manage persistent ecosystem-based threats. US federal land management and natural resource agencies have adopted this framework as a foundation for prioritizing sage-grouse conservation resources and determining effective restoration and management strategies. Because threats and strategies to address them cross-cut program areas, an integrated approach that includes wildland fire operations, postfire rehabilitation, fuels management, and habitat restoration is being used. We believe this approach is applicable to species conservation in other largely intact ecosystems with persistent, ecosystem-based threats.

Management of conservation-reliant species can be complicated by the need to manage ecosystem processes that operate at extended temporal horizons. One such process is the role of fire in regulating abundance of expanding conifers that disrupt sage-grouse habitat in the northern Great Basin of the United States. Removing conifers by cutting has a beneficial effect on sage-grouse habitat. However, effects may last only a few decades because conifer seedlings are not controlled and the seed bank is fully stocked. Fire treatment may be preferred because conifer control lasts longer than for mechanical treatments. The amount of conservation needed to control conifers at large temporal and spatial scales can be quantified by multiplying land area by the time needed for conifer abundance to progress to critical thresholds (i.e., “conservation volume”). The contribution of different treatments in arresting conifer succession can be calculated by dividing conservation volume by the duration of treatment effect. We estimate that fire has approximately twice the treatment life of cutting at time horizons approaching 100 yr, but, has high up-front conservation costs due to temporary loss of sagebrush. Cutting has less up-front conservation costs because sagebrush is unaffected, but it is more expensive over longer management time horizons because of decreased durability. Managing conifers within sage-grouse habitat is difficult because of the necessity to maintain the majority of the landscape in sagebrush habitat and because the threshold for negative conifer effects occurs fairly early in the successional process. The time needed for recovery of sagebrush creates limits to fire use in managing sage-grouse habitat. Utilizing a combination of fire and cutting treatments is most financially and ecologically sustainable over long time horizons involved in managing conifer-prone sage-grouse habitat.

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

Western rangelands are currently under severe threat from exotic annual grasses. To successfully manage rangelands that are either infested with or susceptible to exotic annual grasses, we must focus on increasing resilience to disturbance and resistance to exotic annual grass invasion. Here, we present a fuel-based model and research framework for Wyoming big sagebrush (Artemisia tridentatassp. wyomingensisBeetle & Young) rangelands that focuses on increasing resilience to fire and resistance to exotic annual grasses through the maintenance of perennial bunchgrasses. By maintaining perennial bunchgrass, exotic annual grasses have limited resources, thus decreasing the invasibility of the site. In order for the fuel-based model to be effective in guiding land management practices, research that evaluates the interactions between biotic and abiotic factors that influence fire-induced bunchgrass mortality is needed. Hence, we propose a research framework to identify and fill potential gaps in current scientific knowledge. We also suggest potential research objectives that are necessary to make informed management decisions before wildfire, with a goal to ultimately decreasing our reliance on marginally successful postfire restoration practices through preemptive management strategies.

Declining greater sage-grouse populations are causing concern for the future of this species across the western United States. Major ecosystem issues, including exotic annual grass invasion and conifer encroachment, threaten vast acreages of sagebrush rangeland and are primary threats to sage-grouse. We discuss types of problems facing sage-grouse habitat and argue that complex ecosystem problems may be difficult to address under the Endangered Species Act as currently applied. Some problems, such as anthropogenic development, can be effectively regulated to produce a desired outcome. Other problems that are complex and involve disruption of ecosystem processes cannot be effectively regulated and require ongoing commitment to adaptive management. We believe that historical inertia of the regulatory paradigm is sufficient to skew management toward regulatory mechanisms, even though complex ecosystem problems impact large portions of the sage-grouse range. To overcome this situation, we suggest that the regulatory approach embodied in the Endangered Species Act be expanded to include promoting management trajectories needed to address complex ecosystem problems. This process should begin with state-and-transition models as the basis for a conceptual framework that outlines potential plant communities, their value as sage-grouse habitat, and their ecological status. Desired management trajectories are defined by maintenance of an ecologically resilient state that is of value as sage-grouse habitat, or movement from a less desired to a more desired state. Addressing complex ecosystem problems will involve shifting conservation roles. Under the regulatory approach, programmatic scales define regulatory policies, and local scales focus on implementing those policies. With complex ecosystem problems, programmatic scales empower local conservationists to make decisions necessary to adaptively manage problems. Putting ecosystem management on par with traditional regulatory actions honors obligations to provide regulatory protections while maintaining the capacity of the ecosystem to produce habitat and greatly expands the diversity of stakeholders willing to participate in sage-grouse conservation.

Sagebrush plays an important role in the ecological functions of sagebrush steppe plant communities and is a necessary component of habitat for a variety of wildlife including greater sage-grouse (Centrocercus urophasianus). At lower elevations, increased fire frequency associated with exotic annual grass invasion has heightened the need for effective sagebrush restoration strategies, but existing techniques have been largely ineffective. Our objective was to evaluate “pile seeding” (placing mature seed heads on the ground) of Wyoming big sagebrush (Artemisia tridentatasubsp. wyomingensis) as an alternative to broadcast seeding. We used a randomized block design (n = 5) replicated in 2 yr at two contrasting ecological sites in southeastern Oregon. Treatments applied to 100 × 1.5 m plots included 1) pile seeding (four mature seed heads · pile--1 × 10 piles · plot-1), 2) broadcast seeding (0.5 kg pure live seed [PLS] · ha-1), and 3) natural recovery (i.e., nonseeded). Planting occurred in fall 2008 and 2009, and plots were monitored for seedling establishment for three or two growing seasons postplanting. Seedling density was estimated at the plot scale within a 50-cm radius of each seed head pile (“island scale”). In the year following planting, sagebrush seedling density at the plot scale was up to 60-fold higher (P ≤ 0.05) in pile-seeded plots compared to natural recovery and broadcast plots. Seedling mortality was high (up to 98% reduction in density) for pile-seeded plots between the first and second growing seasons postplanting and differences between broadcast and pile-seeded plots dissipated by 2–3 yr postplanting. Although pile-seeding had higher initial density than broadcast seeding, neither technique had sufficient multiyear survival to suggest restoration efficacy at the plot scale. Seedling density at the island scale suggests that pile-seeding may be useful for establishing sagebrush islands, depending on year conditions. Research is needed to determine strategies capable of increasing long-term sagebrush seedling survival.

Monotypic stands of crested wheatgrass (Agropyron cristatum[L] Gaertm. and Agropyron desertorum[Fisch.] Schult.), an introduced grass, occupy vast expanses of the sagebrush steppe. Efforts to improve habitat for sagebrush-associated wildlife by establishing a diverse community of native vegetation in crested wheatgrass stands have largely failed. Instead of concentrating on a diversity of species, we evaluated the potential to restore the foundation species, Wyoming big sagebrush (Artemisia tridentataspp. wyomingensis[Beetle & A. Young] S. L. Welsh), to these communities. We investigated the establishment of Wyoming big sagebrush into six crested wheatgrass stands (sites) by broadcast seeding and planting seedling sagebrush across varying levels of crested wheatgrass control with glyphosate. Planted sagebrush seedlings survived at high rates (∼ 70% planted sagebrush survival 3yr postplanting), even without crested wheatgrass control. However, most attempts to establish sagebrush by broadcast seeding failed. Only at high levels of crested wheatgrass control did a few sagebrush plants establish from broadcasted seed. Sagebrush density and cover were greater with planting seedlings than broadcast seeding. Sagebrush cover, height, and canopy area were greater at higher levels of crested wheatgrass control. High levels of crested wheatgrass control also created an opportunity for exotic annuals to increase. Crested wheatgrass rapidly recovered after glyphosate control treatments, which suggests multiple treatments may be needed to effectively control crested wheatgrass. Our results suggest that planting sagebrush seedlings can structurally diversify monotypic crested wheatgrass stands to provide habitat for sagebrush-associated wildlife. Though this is not the full diversity of native functional groups representative of the sagebrush steppe, it is a substantial improvement over other efforts that have largely failed to alter these plant communities. We also hypothesize that planting sagebrush seedlings in patches or strips may provide a relatively inexpensive method to facilitate sagebrush recovery across vast landscapes where sagebrush has been lost.

Within the sagebrush steppe ecosystem, sagebrush plants influence a number of ecosystem properties, including nutrient distribution, plant species diversity, soil moisture, and temperature, and provide habitat for a wide variety of wildlife species. Recent increases in frequency and size of wildfires and associated annual grass expansion within the Wyoming big sagebrush alliance have increased the need for effective sagebrush restoration tools and protocols. Our objectives were to quay the success of Wyoming big sagebrush transplants relative to transplant stock (nursery seedlings vs. wildlings) across different ecological sites and vegetation types and to test the hypothesis that reduction of herbaceous vegetation would increase survival of transplanted sagebrush. We used a randomized block (reps=5) design at each of three sites—1) cheatgrass dominated, 2) native plant dominated, and 3) crested wheatgrass dominated—near Elko, Nevada. Treatments included plant stock (nursery stock or locally harvested wildlings) and herbicide (glyphosate) to reduce competition from herbaceous vegetation. Transplants were planted in the spring of 2009 and 2010 and monitored for survival. Data were analyzed for site and treatment effects using mixed-model ANOVA. Surviving plant density at and 2yr postplanting was generally highest (up to 3-fold) on the native site (P<0.05). Density of surviving transplants was almost 3-fold higher for nursery stock on most sites for the 2009 planting, but differences in survival by planting stock were minimal for the 2010 planting. Glyphosate application increased surviving plant density up to 300% (depending on site) for both years of planting. High labor and plant material investments (relative to traditional drilling or broadcasting) may limit the size of projects for which sagebrush transplants are practical, but these costs may be partially offset by high success relative to traditional methods. Our data indicate that sagebrush transplants can be effective for establishing sagebrush on depleted sites.

In sagebrush rangelands perennial bunchgrasses are typically seeded in fall and a high proportion of planted seeds germinate prior to winter onset but fail to emerge in spring. Our objectives were to evaluate freezing tolerance of germinated but nonemergent bluebunch wheatgrass seeds under laboratory conditions. We used data from a 2-yr pilot study to determine overwinter freezing temperature and duration for soils in southeastern Oregon. We then conducted two experiments to assess freezing tolerance. In experiment 1, bluebunch wheatgrass seeds were planted in control pots and compared to seeds planted at early, mid, or late postgermination stages. Pots from each treatment were placed in a grow room maintained at 12h 40min light/11h 20min dark photoperiod, with a constant temperature of 22°C for 30 d either immediately or following a 30-d freeze. In experiment 2, germinated bluebunch wheatgrass seeds were planted in pots that were left nonfrozen or were frozen for a specified duration prior to a 30-d period in the grow room. Emergence density and tillers · seedling−1were quantified for both experiments. The number of days per year for freezing soil conditions in the pilot study ranged yearly from 25 to 51; maximum duration of continuous freezing was 16.5 and 11.2 d. Freezing reduced or eliminated seedling emergence at all postgermination stages (P < 0.001) and tiller density was reduced by at least 50% (P < 0.001). Maximum reduction in seedling density (P < 0.001) was realized within 4 d of initiation of freezing and tillers · seedling−1were reduced 30–70% with > 6 d of freezing (P = 0.001). Our data indicate that freezing-associated mortality of germinated but nonemergent bluebunch wheatgrass seedlings can be extremely high and suggest that management practices to reduce prewinter germination of seeds could improve subsequent emergence and seeding success.

Establishing perennial grasses from seed in postdisturbance Wyoming big sagebrush (Artemesia tridentatasubsp. wyomingensisWelsh) communities is often unsuccessful, due in part to a lack of knowledge of the seedling ecology of perennial grasses. We examined the influence of planting timing on germination and seedling demography of bluebunch wheatgrass (Pseudoroegneria spicata[Pursh] A. Love) in the northern Great Basin. In 2008 (year 1) and 2009 (year 2) we planted seeds monthly, September–December, in 1-m2plots (500 seeds per plot) using a randomized block design with five replications. Germination timing was indexed using seed bags placed adjacent to 1-m2plots and retrieved at 2-wk intervals in fall and 1-mo intervals in spring. Seedlings were marked in March–June of the year following planting; seedlings alive in July were considered initially established. Planting in September and October had up to 80% germination prior to winter, whereas December plantings germinated mainly in spring and at reduced rates (15–35%). Seeds planted in September and October emerged approximately a month earlier than November–December plantings. The percentage of germinated seeds that emerged was highest for September–October plantings but the percentage of emergent seeds surviving to the end of the first growing season was highest for later plantings. Final seedling density was lowest for November planting in year 1 and highest for September and October planting in year 2. Our data indicate that timing of and performance at critical stages of seedling development were affected by planting month. We suggest that it may be possible to use emerging technologies (e.g., seed coatings or germplasm manipulations) to produce variable chronologies of seedling development with single plantings and allow managers to exploit multiple temporal windows of opportunity for seedling establishment.

Riparian ecosystems provide many ecosystem services, including serving as an important forage resource for livestock grazing operations. We evaluated defoliation impacts on above- and belowground production, and net ecosystem exchange of CO2(NEE), in a wet sedge (Carex nebrascensisDewey)-dominated plant community. In June or July of 2004–2005, experimental plots were clipped to 10 cm stubble height and paired control plots left unclipped. All plots were clipped to 2.5 cm in mid-September, and end-of-season and season-long aboveground production calculated. Root ingrowth cores were used to estimate annual root production and root length density (RLD). A portable gas exchange system and plexiglass chamber were used to measure NEE in 2005. An elevated water table in 2005 vs. 2004 was associated with higher (P &spilt; 0.001) season-long aboveground production (about double), but lower (P ≤ 0.05) belowground production (about half). Total productivity did not differ between years, but below-:aboveground ratios were 3× higher in 2004 vs. 2005. RLD was not different between years (P &spigt; 0.05). Clipping reduced (P ≤ 0.05) end-of-season aboveground standing crop by 33% to 73% depending on clipping month and year. Effects of clipping month on season-long aboveground production were inconsistent between years; June clipping decreased (P ≤ 0.05) production (-10%) in 2005 and July clipping decreased (P ≤ 0.05) production (-25%) in 2004. NEE for June-clipped plots recovered within 1 mo of clipping, whereas NEE for plots clipped in July remained below unclipped levels at the end of the growing season. Water table levels strongly influenced below-:aboveground ratios, although total production was relatively stable between years. Year effects overwhelmed clipping effects on season-long aboveground production. Defoliation after mid-summer did not allow recovery of photosynthetic capacity by the end of the growing season, suggesting the potential for long-term impact with regular late-season defoliation.

Livestock grazing potentially has substantial influence on fuel characteristics in rangelands around the globe. However, information quantifying the impacts of grazing on rangeland fuel characteristics is limited, and the effects of grazing on fuels are important because fuel characteristics are one of the primary factors determining risk, severity, continuity, and size of wildfires. We investigated the effects of long-term (70+ yr) livestock grazing exclusion (nongrazed) and moderate levels of livestock grazing (grazed) on fuel accumulations, continuity, gaps, and heights in shrub-grassland rangelands. Livestock used the grazed treatment through 2008 and sampling occurred in mid- to late summer in 2009. Nongrazed rangelands had over twofold more herbaceous standing crop than grazed rangelands (P < 0.01). Fuel accumulations on perennial bunchgrasses were approximately threefold greater in nongrazed than grazed treatments. Continuity of fuels in nongrazed compared to grazed treatments was also greater (P < 0.05). The heights of perennial grass current year’s and previous years’ growth were 1.3-fold and 2.2-fold taller in nongrazed compared to grazed treatments (P < 0.01). The results of this study suggest that moderate livestock grazing decreases the risk of wildfires in sagebrush steppe plant communities and potentially other semi-arid and arid rangelands. These results also suggest wildfires in moderately grazed sagebrush rangelands have decreased severity, continuity, and size of the burn compared to long-term nongrazed sagebrush rangelands. Because of the impacts fuels have on fire characteristics, moderate levels of grazing probably increase the efficiency of fire suppression activities. Because of the large difference between fuel characteristics in grazed and nongrazed sagebrush rangelands, we suggest that additional management impacts on fuels and subsequently fires need to be investigated in nonforested rangelands to protect native plant communities and prioritize management needs.

Woody plants can cause localized increases in resources (i.e., resource islands) that can persist after fire and create a heterogeneous environment for restoration. Others have found that subcanopies have increased soil organic matter, nitrogen, and carbon and elevated post-fire soil temperature. We tested the hypothesis that burned sagebrush subcanopies would have increased seedling establishment and performance of post-fire seeded perennial bunchgrasses compared to burned interspaces. We used a randomized complete block design with five study sites located in southeast Oregon. The area was burned in a wildfire (2007) and reseeded in the same year with a seed mix that included non-native and native perennial bunchgrasses. Seedling density, height, and reproductive status were measured in October 2008 in burned subcanopy and interspace microsites. Non-native perennial grasses had greater densities than native species (P < 0.001) and were six times more abundant in burned subcanopies compared to burned interspaces (P < 0.001). Density of natives in burned subcanopies was 24-fold higher than burned interspaces (P  =  0.043). Seedlings were taller in burned subcanopies compared to burned interspaces (P  =  0.001). Subcanopy microsites had more reproductive seedlings than interspace microsites (P < 0.001). Our results suggest that under the fire conditions examined in this study, pre-burn shrub cover may be important to post-fire restoration of perennial grasses. Determining the mechanisms responsible for increased seeding success in subcanopy microsites may suggest tactics that could be used to improve existing restoration technologies.

Management of rangelands, and natural resources in general, has become increasingly complex. There is an atmosphere of increasing expectations for conservation efforts associated with a variety of issues from water quality to endangered species. We argue that many current issues are complex by their nature, which influences how we approach them. We define a complex problem as one that varies in time and space. In other words, one answer may not be correct for all sites or during all years. For simple problems a generalized answer may be sufficient, and even for complex problems, general rules provide a good starting point. However, we suggest that it is important to distinguish between simple and complex problems. Several key obstacles emerge when considering complex natural resource problems, namely, 1) no single entity can handle all aspects of the problem and 2) significant knowledge gaps exist and will continue to exist into the future. We suggest that overcoming these obstacles will benefit from 1) a framework for effective partnerships and 2) a mechanism for continuous learning. Managing complex problems will require some combination of the following: 1) a process-based understanding of the problem (i.e., what causes variation in time and space), 2) adaptive management, and 3) effective coordination of research and management. There are many examples of organizations applying portions of these approaches to complex problems; however, it seems that in many cases the process has simply evolved in that direction rather than being a planned strategy. We suggest that as a profession we need to have a discussion about the nature of the problems we are addressing and how researchers and managers can jointly address these problems.

Belowground plant biomass plays a critical role in the maintenance of riparian ecosystems and generally constitutes the majority of the total biomass on a site. Despite this importance, belowground dynamics of riparian plant species are not commonly investigated, in part because of difficulties of sampling in a belowground riparian environment. We investigated the field utility of a root-ingrowth sampling technique for measuring root production. We established four streamside sampling sites in southeastern Oregon, and randomly located four plots within each site. In each plot we established two 7.6-cm–diameter sand-filled ingrowth cores in September of 2004. In September of 2005 we harvested the cores with the use of a vacuum sampling technique in which a 5.1-cm–diameter camphored polyvinyl chloride casing was driven into the center of the root core and sand and root materials were suctioned out. Root-length density was determined by computer image analysis, and roots were dried and weighed to determine production by weight. Results indicate that root-length density averaged 7.2 (± 0.7) cm · cm-3across sites and root-production index was 356.7 (± 20.6) g · m-2. Our index to root production by weight was consistent with previous estimates of annual root production reported in the literature. Our sampling technique proved to be a practical solution for root sampling in riparian environments, and helps overcome some of the difficulties in sequential coring of saturated soils. Use of any ingrowth core technique to index root production can potentially bias production estimates because of the artificial, root-free environment of the core. However, these biases should be consistent across sites, making ingrowth cores useful for determining differences between manipulative treatments.

•Invasive annual grasses on sagebrush rangelands are negatively impacting land uses and values ranging from forage for grazing livestock to native plant diversity, wildlife habitat, and human safety via associated increases in the wildfire footprint.•In December 2020 a diverse group of managers, scientists, and government officials held a symposium to discuss existing and emerging options for ameliorating the annual grass threat and associated impacts in the Northern Great Basin region.•I provide a broad overview of sagebrush plant community ecology, how that ecology has varied through time, the role of invasive annual grasses in influencing sagebrush plant community ecology, and thoughts on a productive path forward.•My broad overview serves as an operational context framing the importance of and relationships between the papers in this Special Issue.

Seed-based restoration of wildlife-important shrubs following wildfire is a management priority in many ecosystems. However, post-fire restoration success is spatiotemporally variable and establishment from seed frequently fails in arid and semi-arid rangelands. There may be opportunities to improve restoration success by taking advantage of small-scale spatial variability in environmental characteristics. Woody plants create distinct post-fire microsites, that may influence establishment and growth of seeded species, under their canopies (canopies) compared to between their canopies (interspaces). Immediately after fire, former canopies generally have less vegetation and greater soil nutrient concentrations compared to interspaces. Thus, former canopy compared to interspace microsites may be more favorable for establishment and growth of seeded species, but rapid exotic plant invasion of former canopy microsites may hinder success. We evaluated seeding bitterbrush (Purshia tridentataPursh DC) after wildfire in former western juniper (Juniperus occidentalisssp. occidentalisHook) canopy compared to interspace microsites at six locations for three years post-seeding. Bitterbrush abundance was 3.6-fold greater in former canopy compared to interspace microsites after three years. Bitterbrush height was 1.5 to 2.5-fold greater in former canopy compared to interspace microsites. The first year after fire, exotic annual grass cover was 15.6-fold greater in interspace compared to canopy microsites. Abundance and cover of other herbaceous vegetation were generally also greater in the interspace. Exotic annual grass and native bunchgrass abundance increased substantially over time in former canopy microsites, suggesting abundant resource availability. Less herbaceous competition and presumably greater resource availability in former canopies probably resulted in greater success of seeded bitterbrush. These results suggest that capitalizing on spatial variability in environments can be used to increase restoration efficiency. After fire in western juniper-encroached rangelands, former juniper canopy microsites are a favorable environment for establishment and growth of seeded bitterbrush and could be targeted for restoration efforts to improve efficiency.

Management of areas invaded by cheatgrass (Bromus tectorum)continues to be one of the greatest challenges for US Great Basin ecosystems. Targeted cattle grazing in the fall and winter has shown positive results as a management tool to reduce dormant fine fuel biomass within cheatgrass-invaded areas, but management of targeted grazing within large pastures can be challenging. We evaluated the use of strategically placed liquid protein supplement stations over a 4-wk period in the fall to focus cattle grazing along a linear transect stretching away from water to reduce residual cheatgrass biomass on a production-scale, working ranch from 2014 to 2017. Liquid protein supplement stations were moved approximately 1 km farther from water during each week of the study, eventually reaching 4 km from a single water source. Global Positioning System−tracked cattle visited supplement stations 52% ± 4% of the days during the study period and were within 100 m of the supplement station transect line 17.7% ± 2.6% of the time: more than 3 × greater (P = 0.07) than random locations (5.1% ± 2.6%). Week of the study and the subsequent supplement distance from water did not influence the number of visits cattle made to supplement. The duration that cattle remained at supplement was greater in wk 4, when supplement was placed 4 km from water, compared with wk 1 and 2, when the supplement was 1 and 2 km from water, respectively. At the conclusion of grazing, utilization along the supplement station transect averaged 66.0% ± 5.7% and did not differ between supplement stations at 1 km, 3 km, or 4 km from water. Strategic supplementation provides a valuable tool to target cattle grazing at specific locations within cheatgrass-invaded systems to reduce fine fuel buildup during the dormant season.

Exotic annual grass invasion and dominance of sagebrush-bunchgrass steppe is a concern because it decreases biodiversity and promotes frequent wildfires. Management is needed to reduce exotic annual grasses to prevent sagebrush-bunchgrass communities from transitioning to annual grasslands. Grazing during the off-season (fall-winter) has shown promise at reducing exotic annual grasses, but it has not been evaluated in plant communities dominated by sagebrush and native bunchgrasses. We compared moderate grazing during the off-season with not grazing in five Wyoming big sagebrush (Artemisia tridentatassp. wyomingensis[Beetle & A. Young] S.L. Welsh)-bunchgrass communities in the northern Great Basin. Treatments were applied every year for 10 years (2009-10 through 2018-19). Plant community characteristics were measured after treatments had been applied from 6 to 10 years. Off-season grazing reduced exotic annual grass density and cover. After a decade, annual grass cover was 2-fold greater in ungrazed areas. Sandberg bluegrass (Poa secundaJ. Presl) density increased with off-season grazing, but large bunchgrass density was similar between off-season grazed and ungrazed areas. Perennial and annual forb density and cover were similar between off-season grazed and ungrazed treatments. Biological soil crust cover was also similar between off-season grazed and ungrazed areas. The results of this study provide strong evidence that off-season grazing has application for managing exotic annual grasses in sagebrush-bunchgrass steppe. Considering the vast scope of the exotic annual grass problem, properly applied grazing may be the most cost-efficient tool to mediate the impacts of annual grass invasion.

Forage selection patterns of cattle in sagebrush (ArtemisiaL.) communities are influenced by a variety of environmental and plant-associated factors. The relative preference of cattle for interspace versus under-sagebrush canopy bunchgrasses has not been documented. Potential preferences may indirectly affect habitat for sage-grouse and other ground-nesting birds. Our objectives were to investigate grazing patterns of cattle with respect to undercanopy (shrub) and interspace tussocks, determine the influence of cattle grazing on screening cover, and relate shrub morphology to undercanopy grazing occurrence. Eighteen-day replicated trials were conducted in the summers of 2003 and 2004. Findings suggest cattle initially concentrate grazing on tussocks between shrubs, and begin foraging on tussocks beneath shrubs as interspace plants are depleted. Grazing of undercanopy grass tussocks was negligible at light-to-moderate utilization levels (< 40% by weight). Grass tussocks under spreading, umbrella-shaped shrub canopies were less likely (P< 0.001) to be grazed than those beneath erect, narrow canopies. Horizontal screening cover decreased (P< 0.001) with pasture utilization. At the trial’s end, removal of 75% of the herbaceous standing crop induced about a 5% decrease in screening cover in all strata from ground level to 1m with no differences among strata (P= 0.531). This implied that shrubs constituted the majority of screening vegetation. Our data suggest that conservative forage use, approaching 40% by weight, will affect a majority (about 70%) of interspace tussocks and a lesser proportion (about 15%) of potential nest-screening tussocks beneath sagebrush. Probability of grazing of tussocks beneath shrubs, however, is also affected by shrub morphology. These findings will help managers design grazing programs in locales where habitat for ground nesting birds is a concern.

Sagebrush cover is often estimated with the use of the line intercept method. However, a lack of standardized protocols may lead to variable estimates of sagebrush canopy cover. Our objectives were to determine the influence of gap size on 1) sagebrush canopy cover estimates, 2) time needed to read a transect, and 3) among-observer variability in sagebrush canopy cover estimates. We utilized 5-, 10-, and 15-cm gaps, and defined a gapas a lack of continuous live or dead shrub canopy. In instances where a segment of dead cover was less than the gap size and adjoined live cover, the dead cover was measured as live. We evaluated canopy cover at 6 Wyoming big sagebrush (Artemisia tridentataNutt. ssp. WyomingensisBeetle & A. Young) sites in southeast Oregon. At each site, four 2-person teams measured sagebrush canopy intercept along 50-m transects. Each transect was read by multiple teams to allow for assessment of among-observer variability. Intercept values were converted to percent canopy cover and we used analysis of variance to determine the influence of site and gap size on measurement time and cover estimates. Observer variability was highest at the intermediate gap size (i.e., 10 cm). Transect measurement time was longest with the use of a 5-cm gap (P < 0.001). Total cover estimates were not related to gap size (P = 0.270). Live canopy cover estimates increased (P < 0.001) from 12.1% to 14.5% with increasing gap size, and cover of dead material decreased (P = 0.015) from 4.4% to 3.2%. These differences are small in magnitude and would not likely change a gross assessment of vegetation status. However, use of a standardized gap size will enhance comparability of canopy cover estimates among studies and will decrease between-year sampling error for repeat monitoring.

Willow (Salix) communities are important components of riparian ecosystems. However, browsing by livestock and wildlife species can negatively impact willow size and abundance, and make restoration efforts difficult. A common solution has been fencing of affected willows to exclude ungulates, but fencing is expensive and may not complement desirable land management strategies. An alternative to fencing is the use of structures that limit access to streamside willows, without excluding ungulate access to the entire riparian zone. We examined the use of felled western juniper trees (Juniperus occidentalisHook) placed over streamside willow shrubs. Four replicates of felled western juniper treatments (covered) and noncovered treatments were applied to a 1.2-km length of stream in southeastern Oregon. Willows (< 2 m) within treatment areas were censused, tagged, examined for evidence of browse-use, and measured for maximum height during August 2002, before treatment. Posttreatment measurements were made in August and October 2003. Results indicate that by August 2003 (posttreatment) the average growth of willows in covered treatments was 25cm (480%) greater than in noncovered treatments. By October 2003 (posttreatment), more shrubs were browsed in noncovered (84%) than covered (39%) treatments. Our data suggest that covering small willow shrubs (< 2m tall) with felled western juniper is an effective deterrent to browsing.

Quantifying woody plant biomass has often proven difficult in the field for reasons that include irregular plant morphology, between-observer variability, and lack of standardized techniques. One potential solution to these challenges is the use of ground-based photographic technology. Our objective was to develop a photo-based technique that could be used to monitor changes in willow (Salixspp.) biomass over time and estimate changes in biomass associated with herbivory. We focused on young willows (≤ 2m in height) because this size class represents a critical life history stage for establishment of willow clumps. In August 2000 and 2001, we harvested 25 willow (Salix boothiiDorn.) clumps and clamped them in front of a fluorescent orange photoboard (150 × 200 cm). Clumps were defoliated of leaves and tips of current annual stem growth (referred to as “biomass”) by hand in 4 to 7 increments and photographed before and after each removal. Images were scanned to digital format and the degree of photoboard obstruction was determined with Adobe® Photoshop® 4.0 software. Regression analysis indicated that visual obstruction of the photoboard was a good predictor of total clump biomass (r2 = 0.89, P < 0.01) as well as biomass remaining following sequential defoliations (r2 = 0.92, P < 0.01). These results suggest our technique provides a reliable index of both willow biomass and utilization within the size class of willow tested. Results might differ with larger willows and increased woody biomass. The technique minimizes observer bias and provides a permanent photo record that can be reanalyzed at a later date if necessary.

•Native perennial grass restoration in the Great Basin is limited by low seedling establishment.•Native seedling establishment is decreased by increased competition from exotic annual grasses and altered fire regimes and have not had sufficient time to adapt.•Non-native bunchgrasses like crested wheatgrass have adapted to human management of grazing systems and possess physiological traits that increase seedling establishment in dynamic rangelands.•We review ecophysiological traits underlying crested wheatgrass success in the Great Basin and suggest these could guide native bunchgrass plant material selection and development.