Encroachment of Great Plains grasslands by fire-sensitive woody plants is a large-scale, regional process that fragments grassland landscapes. Using prairie grouse (Tympanuchus spp.) of conservation concern,we apply hierarchy theory to demonstrate how regional processes constrain lower-level processes and reduce the success of local management. For example, fire and grazingmanagementmay be locally important to conservation, but the application of fire and grazing disturbances rarely cause irreversible fragmentation of grasslands in the Great Plains. These disturbance processes cause short-term alterations in vegetation conditions that can be positive or negative, but from a long-term perspective fire maintains large tracts of continuous rangelands by limiting woody plant encroachment. Conservation efforts for prairie grouse should be focused on landscape processes that contribute to landscape fragmentation, such as increased dominance of trees or conversion to other land uses. In fact, reliance on localmanagement (e.g.,maintaining vegetation structure) to alter prairie grouse vital rates is less important to grouse population persistence given contemporary landscape level changes. Changing grass height, litter depth, or increasing the cover of forbs may impact a fewremaining prairie-chickens, but itwill not create useable space at a scale relevant to the historic conditions that existed before land conversion and fire suppression.

Invasivewoody plant expansion is a primary threat driving fragmentation and loss of sagebrush (Artemisia spp.) and prairie habitats across the central andwestern United States. Expansion of native woody plants, including conifer (primarily Juniperus spp.) and mesquite (Prosopis spp.), over the past century is primarily attributable to wildfire suppression, historic periods of intensive livestock grazing, and changes in climate. To guide successful conservation programs aimed at reducing top-down stressors, we mapped invasive woody plants at regional scales to evaluate landscape level impacts, target restoration actions, and monitor restoration outcomes. Our overarching goal was to produce seamless regional products across sociopolitical boundaries with resolution fine enough to depict the spatial extent and degree of woody plant invasion relevant to greater sage-grouse (Centrocercus urophasianus) and lesser prairie-chicken (Tympanuchus pallidicinctus) conservation efforts. We mapped tree canopy cover at 1-m spatial resolution across an 11-state region (508 265 km²). Greater than 90% of occupied lesser prairie-chicken habitat was largely treeless for conifers (<1% canopy cover), whereas > 67% was treeless for mesquite. Conifers in the higher canopy cover classes (16–50% and >50% canopy cover) were scarce (<2% and 1% canopy cover), as was mesquite (<5% and 1% canopy cover). Occupied habitat by sagegrouse was more variable but also had a relatively large proportion of treeless areas ( =71, SE=5%). Lowto moderate levels of conifer cover (1–20%) were fewer ( = 23, SE = 5%) as were areas in the highest cover class (>50%; = 6, SE = 2%). Mapping indicated that a high proportion of invading woody plants are at a low to intermediate level. Canopy cover maps for conifer and mesquite resulting from this study provide the first and most geographically complete, high-resolution assessment of woody plant cover as a top-down threat to western sage-steppe and prairie ecosystems.

In sagebrush (Artemisia spp.) ecosystems, encroachment of pinyon (Pinus spp.) and juniper (Juniperus spp.; hereafter, “pinyon-junipeR&Rdquo;) trees has increased dramatically since European settlement. Understanding the impacts of this encroachment on behavioral decisions, distributions, and population dynamics of greater sage-grouse (Centrocercus urophasianus) and other sagebrush obligate species could help benefit sagebrush ecosystem management actions. We employed a novel two-stage Bayesian model that linked avoidance across different levels of pinyon-juniper cover to sage-grouse survival. Our analysis relied on extensive telemetry data collected across 6 yr and seven subpopulations within the Bi-State Distinct Population Segment (DPS), on the border of Nevada and California. The first model stage indicated avoidance behavior for all canopy cover classes on average, but individual grouse exhibited a high degree of heterogeneity in avoidance behavior of the lowest cover class (e.g., scattered isolated trees). The second stage modeled survival as a function of estimated avoidance parameters and indicated increased survival rates for individuals that exhibited avoidance of the lowest cover class. A post hoc frailty analysis revealed the greatest increase in hazard (i.e., mortality risk) occurred in areas with scattered isolated trees consisting of relatively high primary plant productivity. Collectively, these results provide clear evidence that local sage-grouse distributions and demographic rates are influenced by pinyon-juniper, especially in habitats with higher primary productivity but relatively low and seemingly benign tree cover. Such areas may function as ecological traps that convey attractive resources but adversely affect population vital rates. To increase sage-grouse survival, our model predictions support reducing actual pinyon-juniper cover as low as 1.5%, which is lower than the published target of 4.0%. These results may represent effects of pinyon-juniper cover in areas with similar ecological conditions to those of the Bi-State DPS, where populations occur at relatively high elevations and pinyon-juniper is abundant and widespread.

Fine-scale spatiotemporal studies can better identify relationships between individual survival and habitat fragmentation so thatmechanistic interpretations can be made at the population level. Recent advances in Global Positioning System(GPS) technology and statistical models capable of deconstructing high-frequency location data have facilitated interpretation of animal movement within a behaviorally mechanistic framework. Habitat fragmentation due to singleleaf pinyon (Pinus monophylla; hereafter pinyon) and Utah juniper (Juniperus osteosperma; hereafter juniper) encroachment into sagebrush (Artemisia spp.) communities is a commonly implicated perturbation that can adversely influence greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) demographic rates. Using an extensive GPS data set (233 birds and 282,954 locations) across 12 study sites within the Great Basin, we conducted a behavioral change point analysis and constructed Brownian bridgemovementmodels fromeach behaviorally homogenous section.Wefound the probability of encountering pinyon-juniper among adults was two and three times greater than that of yearlings and juveniles, respectively. However, the movement rate in response to the probability of encountering pinyon-juniper trees was 1.5 times greater for juveniles. Parameter estimates indicated a 6.1% increase in the probability of encountering pinyonjuniper coupled with a 6.2 km/hour increase in movement speed resulted in a 56%, 42% and 16% increase in risk of daily mortality, for juveniles, yearlings, and adults, respectively. The effect of pinyon-juniper encounters on survival was dependent on movement rate and differed among age class. Under fast speed movements (i.e., flight), mortality risk increased as encountering pinyon-juniper increased across all age classes. In contrast, slower speeds (i.e., average) yielded similar adverse effects for juveniles and yearlings but not for adults. This analytical framework supports a behavioral mechanism that explains reduced survival related to pinyon-juniper within sagebrush environments,whereby encountering pinyon-juniper stimulates riskier movements that likely increase vulnerability to visually acute predators.

Coniferwoodlands expanding into sage-steppe (Artemisia spp.) are a threat to sagebrush obligate species including the imperiled greater sage-grouse (Centrocercus urophasianus). Conifer removal is accelerating rapidly despite a lack of empirical evidence to assess outcomes to grouse. Using a before-after-control-impact design, we evaluated short-term effects of conifer removal on nesting habitat use by monitoring 262 sage-grouse nests in the northern Great Basin during 2010–2014. Tree removal made available for nesting an additional 28% of the treatment landscape by expanding habitat an estimated 9603 ha (3201 ha [±480 SE] annually). Relative probability of nesting in newly restored sites increased by 22% annually, and femaleswere 43%more likely to nestwithin 1000 m of treatments. From 2011 (pretreatment) to 2014 (3 yr after treatments began), 29% of the marked population (9.5% [±1.2 SE] annually) had shifted its nesting activities into mountain big sagebrush habitats that were cleared of encroaching conifer. Grouping treatments likely contributed to beneficial outcomes for grouse as individual removal projects averaged just 87 ha in size but cumulatively covered a fifth of the study area. Collaboratively identifying future priority watersheds and implementing treatments across public and private ownerships is vital to effectively restore the sage-steppe ecosystem for nesting sage-grouse.

The link between individual variation in resource selection (e.g., functional response) and fitness creates a foundation for understanding wildlife-habitat relationships. Although many anthropogenic activities adversely affect these relationships, it is largely unknownwhether projects implemented to benefit wildlife populations actually achieve this outcome. For sagebrush (Artemisia spp.) obligate species such as the greater sage-grouse (Centrocercus urophasianus; sage-grouse), expansion of juniper (Juniperus spp.) and pinyon-pine (Pinus spp.; conifers) woodlands into sagebrush ecosystems has been identified as a conservation threat. This threat is intensifiedwhen a sagebrush ecosystemis bounded by naturally unsuitable habitats. As such, federal, state, and private land managers have implemented landscape-level management to remove conifers on thousands of hectares of sagebrush habitat across the western United States. Despite the scale of contemporary conifer treatments, little was previously known whether sage-grouse will occupy these manipulated landscapes and whether occupancy has consequences on fitness components. To address these questions,we monitored nest and brood success rates for 96 radio-marked sage-grouse from 2012–2015 that inhabited conifer-dominated landscapes in the Box Elder Sage-grouse Management Area in Utah where mechanical conifer removal projects were completed. We then linked sage-grouse resource selection to individual nest (n= 95) and brood (n= 56) success by incorporating random-slope Resource Selection Functions as explanatory predictors in a logistic brood successmodel. Using the novel approach of random slope covariates, we demonstrated that sage-grouse selected for nest and brooding sites closer to conifer removal areas and that the probability of individual nest and brood success declined (β = -0.10 and β = -0.74, respectively) as sage-grouse females selected sites farther from conifer removal areas. Our research provided the first evidence thatmechanical conifer removal treatments can increase suitable available breeding habitats for female sage-grouse and that individuals who occupied these areas experienced enhanced nest and brood success.

Loss of native grasslands by anthropogenic disturbances has reduced availability and connectivity of habitat for many grassland species. A primary threat to contiguous grasslands is the encroachment of woody vegetation, which is spurred by disturbances that take on many forms from energy development, fire suppression, and grazing. These disturbances are exacerbated by natural- and human-driven cycles of changes in climate punctuated by drought and desertification conditions. Encroachment of honey mesquite (Prosopis glandulosa) into the prairies of southeastern New Mexico has potentially limited habitat for numerous grassland species, including lesser prairie-chickens (Tympanuchus pallidicinctus). To determine them agnitude of impacts of distribution of mesquite and how lesser prairie-chickens respond tomesquite presence on the landscape in southeastern New Mexico, we evaluated seasonal space use of lesser prairie-chickens in the breeding and nonbreeding seasons. We derived several remotely sensed spatial metrics to characterize the distribution of mesquite. We then used these data to create population-level resource utilization functions and predict intensity of use of lesser prairie-chickens across our study area. Home ranges were smaller in the breeding season compared with the nonbreeding season; however, habitat use was similar across seasons. During both seasons, lesser prairie-chickens used areas closer to leks and largely avoided areas with mesquite. Relative to the breeding season, during the nonbreeding season habitat use suggested a marginal increase in mesquite within areas of low intensity of use, yet aversion to mesquite was strong in areas of medium to high intensity of use. To our knowledge, our study is the first to demonstrate a negative behavioral response by lesser prairie-chickens to woody encroachment in native grasslands. To mitigate one of the possible limiting factors for lesser prairie-chickens, we suggest future conservation strategies be employed by land managers to reduce mesquite abundance in the southern portion of their current range.

Grasslands are among themost imperiled ecosystems in North America. Reasons that grasslands are threatened include conversion to row-crop agriculture, fragmentation, and changes in fire regimes. The reduction of fire processes in remaining prairies has resulted in tree encroachment and establishment in grasslands, further reducing grassland quantity and quality. Grassland birds have been experiencing precipitous population declines in recent decades, commensurate with landscape changes to grasslands. The lesser prairie-chicken (Tympanuchus pallidicinctus Ridgway) is a declining species of prairie grouse of conservation concern. We used second- and third-order habitat selection metrics to test if female lesser prairie-chickens avoid grasslands where trees were present. Our results indicated that female lesser prairie-chickens selected habitats avoiding the nearest trees by 283 m on average, nearly twice as far aswould be expected at random. Lesser prairie-chickenswere 40 timesmore likely to use habitatswith tree densities of 0 trees · ha^-1 than habitats with 5 trees · ha^-1. Probability of use indicated that lesser prairiechickenswere 19 timesmore likely to use habitats 1000 m from the nearest tree when comparedwith using habitats 0 m fromthe nearest tree. Nest survival was not affected at densities < 2 trees · ha^-1; however, we could not test if nest survivalwas affected at greater tree densities as no nestswere detected at densities > 2 trees · ha^-1. Avoidance of trees could be due to perceived increased predation risk, reduced habitat quality, or a combination of these potentially confounding factors. Preventing further establishment and expansion of trees in landscapes occupied by lesser prairie-chickens could contribute to the continued persistence of the species. Additionally, restoring grasslands through tree removal may facilitate conservation efforts for grassland species such as the lesser prairie-chicken by improving habitat quality and promoting expansion of occupied range.

We investigated bird abundance in response to western juniper (Juniperus occidentalis) removal using a short-term chronosequence approach and generated estimates of density and responses to management for the most abundant species. Stands targeted for tree removal were primarily in the middle stages of juniper encroachment (Phase II, 7 851 ha). Trees were removed using hand felling combined with either lop and scatter, single tree burning, or jackpot burning, which were carried out to minimize loss of shrub cover. Brewer's sparrow (Spizella breweri) density was greater at treated versus untreated portions of the study area. At sites in the third year following tree removal, Brewer's sparrow density was 23.6 (95% confidence interval [CI]: 19.4–27.8) territories per km² higher than locations that had not yet been treated. This equates to a net increase of 1 212-1 737 nesting pairs within the project area. Green-tailed towhee increased by 4.6 (95% CI: 3.1–6.1) territories per km² for an estimated project wide increase of 194–381 nesting pairs, and vesper sparrow (Poocetes gramineus) increased by 6.5 (95% CI: 4.6–8.4) territories per km² corresponding to an estimated increase of 460–559 nesting pairs within the project area. Density of gray flycatcher (Empidonax wrighti) was lower in cut areas, and over the entire project area we estimate a net loss of 183–486 nesting pairs as a result of juniper tree removal. This study demonstrates that conifer removal projects designed to retain shrub cover and structure can have benefits to multiple species of ground and shrub nesting birds, including several species of conservation concern.

Recent and unprecedented scale of greater sage-grouse (Centrocercus urophasianus) conservation in the American West enables assessment of community-level benefits afforded to other sagebrush-obligate species. We use North American Breeding Bird Survey (BBS) count data and machine-learning to assess predictors influencing spatial distribution and abundance of three sagebrush-obligate songbirds (Brewer's sparrow [Spizella breweri], sagebrush sparrow [Artemisiospiza nevadensis], and sage thrasher [Oreoscoptes montanus]). We quantified co-occurrence of songbird abundance with sage-grouse lek distributions using point pattern analyses and evaluated the concurrence of songbird abundance within sage-grouse habitat restoration and landscape protection. Sagebrush land-cover predictors were positively associated with the abundance of each songbird species in models that explained 16–37% of variation in BBS route level counts. Individual songbird models identified an apparent 40% threshold in sagebrush land-cover, over which songbird abundances nearly doubled. Songbird abundances were positively associated with sage-grouse distributions (P b 0.01); range-wide, landscapes supporting N 50% of males on leks also harbored 13–19% higher densities of songbirds compared with range-wide mean densities. Eighty-five percent of the conifer removal conducted through the Sage Grouse Initiative coincided with high to moderate Brewer's sparrow abundance. Wyoming's landscape protection (i.e., “core area”) strategy for sage-grouse encompasses half the high to moderate abundance sagebrush sparrow and sage thrasher populations. In the Great Basin half the high to moderate abundance sagebrush sparrow and sage thrasher populations coincide with sage-grouse Fire and Invasive Assessment Tool priorities, where conservation actions are being focused in an attempt to reduce the threat of wildfire and invasive plants. Our work illustrates spatially targeted actions being implemented ostensibly for sage-grouse largely overlap high abundance centers for three sagebrush obligate passerines and are likely providing significant conservation benefits for less well-known sagebrush songbirds and other sagebrush-associated wildlife.

Juniper and piñon coniferous woodlands have increased 2- to 10-fold in nine ecoregions spanning the Intermountain Region of the western United States. Control of piñon-juniper woodlands by mechanical treatments and prescribed fire are commonly applied to recover sagebrush steppe rangelands. Recently, the Sage Grouse Initiative has made conifer removal a major part of its program to reestablish sagebrush habitat for sage grouse (Centrocercus urophasianus) and other species. We analyzed data sets from previous and ongoing studies across the Great Basin characterizing cover response of perennial and annual forbs that are consumed by sage grouse to mechanical, prescribed fire, and low-disturbance fuel reduction treatments. There were 11 sites inwestern juniper (Juniperus occidentalis Hook.) woodlands, 3 sites in singleleaf piñon (Pinus monophylla Torr. & Frém.) and Utah juniper (Juniperus osteosperma[Torr.] Little), 2 sites in Utah juniper, and 2 sites in Utah juniper and Colorado piñon (Pinus edulis Engelm). Western juniper sites were located in mountain big sagebrush (A. tridentata ssp. vaseyana) steppe associations, and the other woodlands were located in Wyoming big sagebrush (A. tridentata ssp. wyomingensis) associations. Site potential appears to be a major determinant for increasing perennial forbs consumed by sage grouse following conifer control. The cover response of perennial forbs, whether increasing (1.5- to 6-fold) or exhibiting no change, was similar regardless of conifer treatment. Annual forbs favored by sage grouse benefitted most from prescribed fire treatments with smaller increases following mechanical and fuel reduction treatments. Though forb abundance may not consistently be enhanced, mechanical and fuel reduction conifer treatments remain good preventative measures, especially in phase 1 and 2 woodlands, which, at minimum, maintain forbs on the landscape. In addition, these two conifer control measures, in the short term, are superior to prescribed fire for maintaining the essential habitat characteristics of sagebrush steppe for sage grouse.

Western Juniper (Juniperus occidentalis Hook.) has greatly expanded in the past 150 years and now dominates over 3.6 million ha of rangeland in the Intermountain Western United States. The impacts of juniper encroachment on critical ecohydrological relationships among snowdistribution, water budgets, plant community transitions, and habitat requirements for wildlife, such as the greater sage grouse (Centrocercus urophasianus), remain poorly understood. The goal of this study is to better understand how juniper encroachment affects water availability for ecohydrologic processes and associatedwildlife habitat in snow-dominated sagebrush (Artemisia spp.) steppe ecosystems. A 6-yr combined measurement and modeling study is conducted to explore differences in snow distribution, water availability, and annual water balances between juniper-dominated and sagebrushdominated catchments. Although there is large interannual variability in both measured weather data and modeled hydrologic fluxes during the study, results indicate that juniper-dominated catchments have greater peak accumulations of snow water equivalent, earlier snow melt, and less streamflow relative to sagebrushdominated catchments. Water delivery is delayed by an average of 9 days in the sagebrush-dominated scenario comparedwith the juniper-dominated scenario as a result of increasedwater storage in snow drifts. The delayed water input to sagebrush-dominated ecosystems in typical water years has wide-ranging implications for available surface water, soil water, and vegetation dynamics associated with wildlife habitat for sagebrush obligates such as sage grouse. Results from this study imply that the retention of high-elevation, sagebrush-dominated landscapes may become crucial for sage grouse habitat management if mid- and low-elevation precipitation continues to transition from snow to rain dominated.

The Endangered Species Act (ESA) continues to serve as one of the most powerful and contested federal legislative mandates for conservation. In the midst of heated debates, researchers, policy makers, and conservation practitioners champion the importance of cooperative conservation and social-ecological systems approaches, which forge partnerships at multiple levels and scales to address complex ecosystem challenges. However, few real-world examples exist to demonstrate how multifaceted collaborations among stakeholders who share a common goal of conserving at-risk species may be nestedwithin a systems framework to achieve social and ecological goals. Here, we present a case study of Greater Sage-grouse (Centrocercus urophasianus) conservation efforts in the “Bi-State” region of California and Nevada, United States. Using key-informant interviews, we explored dimensions and drivers of this landscape-scale conservation effort. Three themes emerged fromthe interviews, including 1) ESA action was transformed into opportunity for system-wide conservation; 2) a diverse, locally based partnership anchored collaboration and engagement acrossmultiple levels and scales; and 3) bestavailable science combined with local knowledge led to “certainty of effectiveness and implementation”—the criteria used by the US Fish and Wildlife Service to evaluate conservation efforts when making listing decisions. Ultimately, collaborative conservation through multistakeholder engagement at various levels and scales led to proactive planning and implementation of conservation measures and precluded the need for an ESA listing of the Bi-State population of Greater Sage-grouse. This article presents a potent example of howa systems approach integrating policy, management, and learning can be used to successfully overcome the conflict-laden and “wicked” challenges that surround at-risk species conservation.

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.