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1.
ABSTRACT Greater sage-grouse (Centrocercus urophasianus) are dependent on sagebrush (Artemisia spp.) for food and shelter during winter, yet few studies have assessed winter habitat selection, particularly at scales applicable to conservation planning. Small changes to availability of winter habitats have caused drastic reductions in some sage-grouse populations. We modeled winter habitat selection by sage-grouse in Alberta, Canada, by using a resource selection function. Our purpose was to 1) generate a robust winter habitat-selection model for Alberta sage-grouse; 2) spatially depict habitat suitability in a Geographic Information System to identify areas with a high probability of selection and thus, conservation importance; and 3) assess the relative influence of human development, including oil and gas wells, in landscape models of winter habitat selection. Terrain and vegetation characteristics, sagebrush cover, anthropogenic landscape features, and energy development were important in top Akaike's Information Criterion-selected models. During winter, sage-grouse selected dense sagebrush cover and homogenous less rugged areas, and avoided energy development and 2-track truck trails. Sage-grouse avoidance of energy development highlights the need for comprehensive management strategies that maintain suitable habitats across all seasons.  相似文献   

2.
ABSTRACT Modification of landscapes due to energy development may alter both habitat use and vital rates of sensitive wildlife species. Greater sage-grouse (Centrocercus urophasianus) in the Powder River Basin (PRB) of Wyoming and Montana, USA, have experienced rapid, widespread changes to their habitat due to recent coal-bed natural gas (CBNG) development. We analyzed lek-count, habitat, and infrastructure data to assess how CBNG development and other landscape features influenced trends in the numbers of male sage-grouse observed and persistence of leks in the PRB. From 2001 to 2005, the number of males observed on leks in CBNG fields declined more rapidly than leks outside of CBNG. Of leks active in 1997 or later, only 38% of 26 leks in CBNG fields remained active by 2004–2005, compared to 84% of 250 leks outside CBNG fields. By 2005, leks in CBNG fields had 46% fewer males per active lek than leks outside of CBNG. Persistence of 110 leks was positively influenced by the proportion of sagebrush habitat within 6.4 km of the lek. After controlling for habitat, we found support for negative effects of CBNG development within 0.8 km and 3.2 km of the lek and for a time lag between CBNG development and lek disappearance. Current lease stipulations that prohibit development within 0.4 km of sage-grouse leks on federal lands are inadequate to ensure lek persistence and may result in impacts to breeding populations over larger areas. Seasonal restrictions on drilling and construction do not address impacts caused by loss of sagebrush and incursion of infrastructure that can affect populations over long periods of time. Regulatory agencies may need to increase spatial restrictions on development, industry may need to rapidly implement more effective mitigation measures, or both, to reduce impacts of CBNG development on sage-grouse populations in the PRB.  相似文献   

3.
Abstract: Considering habitat selection at multiple scales is essential to fully understand habitat requirements and management needs for wildlife species of concern. We used a hierarchical information-theoretic approach and variance decomposition techniques to analyze habitat selection using local-scale habitat variables measured in the field and landscape-scale variables derived with a Geographic Information System (GIS) for nesting greater sage-grouse (Centrocercus urophasianus) in the Powder River Basin (PRB), Montana and Wyoming, USA, 2003–2007. We investigated relationships between habitat features that can and cannot be mapped in a GIS to provide insights into interpretation of landscape-scale—only GIS models. We produced models of habitat selection at both local and landscape scales and across scales, yet multiscale models had overwhelming statistical and biological support. Variance decomposition showed that local-scale measures explained the most pure variation (50%) in sage-grouse nesting-habitat selection. Landscape-scale features explained 20% of pure variation and shared 30% with local-scale features. Both local- and landscape-scale habitat features are important in sage-grouse nesting-habitat selection because each scale explained both pure and shared variation. Our landscape-scale model was accurate in predicting priority landscapes where sage-grouse nests would occur and is, therefore, useful in providing landscape context for management decisions. It accurately predicted locations of independent sage-grouse nests (validation R2 = 0.99) and showed good discriminatory ability with >90% of nests located within only 40% of the study area. Our landscape-scale model also accurately predicted independent lek locations. We estimated twice the amount of predicted nesting habitat within 3 km of leks compared to random locations in the PRB. Likewise we estimated 1.8 times more predicted nesting habitat within 10 km of leks compared to random locations. These results support predictions of the hotspot theory of lek placement. Local-scale habitat variables that cannot currently be mapped in a GIS strongly influence sage-grouse nest-site selection, but only within priority nesting habitats defined at the landscape scale. Our results indicate that habitat treatments for nesting sage-grouse applied in areas with an unsuitable landscape context are unlikely to achieve desired conservation results.  相似文献   

4.
ABSTRACT Sagebrush (Artemisia spp.)-dominated habitats in the western United States have experienced extensive, rapid changes due to development of natural-gas fields, resulting in localized declines of greater sage-grouse (Centrocercus urophasianus) populations. It is unclear whether population declines in natural-gas fields are caused by avoidance or demographic impacts, or the age classes that are most affected. Land and wildlife management agencies need information on how energy developments affect sage-grouse populations to ensure informed land-use decisions are made, effective mitigation measures are identified, and appropriate monitoring programs are implemented (Sawyer et al. 2006). We used information from radio-equipped greater sage-grouse and lek counts to investigate natural-gas development influences on 1) the distribution of, and 2) the probability of recruiting yearling males and females into breeding populations in the Upper Green River Basin of southwestern Wyoming, USA. Yearling males avoided leks near the infrastructure of natural-gas fields when establishing breeding territories; yearling females avoided nesting within 950 m of the infrastructure of natural-gas fields. Additionally, both yearling males and yearling females reared in areas where infrastructure was present had lower annual survival, and yearling males established breeding territories less often, compared to yearlings reared in areas with no infrastructure. Our results supply mechanisms for population-level declines of sage-grouse documented in natural-gas fields, and suggest to land managers that current stipulations on development may not provide management solutions. Managing landscapes so that suitably sized and located regions remain undeveloped may be an effective strategy to sustain greater sage-grouse populations affected by energy developments.  相似文献   

5.
ABSTRACT Rapid expansion of energy development in some portions of the Intermountain West, USA, has prompted concern regarding impacts to declining greater sage-grouse (Centrocercus urophasianus) populations. We used retrospective analyses of public data to explicitly investigate potential thresholds in the relationship between lek attendance by male greater sage-grouse, the presence of oil or gas wells near leks (surface occupancy), and landscape-level density of well pads. We used generalized linear models and generalized estimating equations to analyze data on peak male attendance at 704 leks over 12 years in Wyoming, USA. Within this framework we also tested for time-lag effects between development activity and changes in lek attendance. Surface occupancy of oil or gas wells adjacent to leks was negatively associated with male lek attendance in 5 of 7 study areas. For example, leks that had ≥ 1 oil or gas well within a 0.4-km (0.25-mile) radius encircling the lek had 35–91% fewer attending males than leks with no well within this radius. In 2 of these 5 study areas, negative effects of well surface occupancy were present out to 4.8 km, the largest radius we investigated. Declining lek attendance was also associated with a higher landscape-level density of well pads; lek attendance at well-pad densities of 1.54 well pads/km2 (4 well pads/mile2) ranged from 13% to 74% lower than attendance at unimpacted leks (leks with zero well pads within 8.5 km). Lek attendance at a well-pad density of 3.09 well pads/km2 (8 well pads/mile2) ranged from 77% to 79% lower than attendance at leks with no well pad within 8.5 km. Further, our analysis of time-lag effects suggested that there is a delay of 2–10 years between activity associated with energy development and its measurable effects on lek attendance. These results offer new information for consideration by land managers on spatial and temporal associations between human activity and lek attendance in sage-grouse, and suggest that regional variation is an important consideration in refining existing management strategies.  相似文献   

6.
ABSTRACT Loss of nesting habitat is believed to be a factor in the decline of greater sage-grouse (Centrocercus urophasianus) throughout its range. Few data are available for sage-grouse in Mono County, California, USA, in the most southwestern portion of the species’ range. We studied habitat selection of nesting sage-grouse in Mono County, California, from 2003 to 2005 by capturing and radiotracking females to identify nesting locations. We sampled vegetation at nest sites and randomly selected sites within 200 m of nests and within each of 5 subareas within Mono County. Nest sites were characterized by 42.4 ± 1.3% ( ± SE) shrub canopy cover, 10.5 ± 1.0 cm residual grass height, and 2.7 ± 1.0% residual grass cover. Shrub cover was the only variable found to differentiate nest sites from randomly selected sites. Unlike some other studies, we did not find understory vegetation to be important for selecting nest sites. Mean shrub cover was 38.7 ± 1.5% at random sites within 200 m of nests and 33.6 ± 1.6% at random sites at the approximate scale of home ranges, indicating that nesting females selected nesting areas that contained denser shrubs than their home range, and nest sites that contained greater shrub cover than the vicinity immediately surrounding nests. Our results suggest that managers should consider managing for greater shrub cover in Mono County than what is currently called for in other parts of sage-grouse range and that management for sage-grouse habitat may need to be tied more closely to local conditions.  相似文献   

7.
Energy infrastructure and associated habitat loss can lead to reduced reproductive rates for a variety of species including the greater sage-grouse (Centrocercus urophasianus). Our goal was to refine our understanding of how the physical footprint of energy development relates to sage-grouse nest and brood survival. Our survival analyses were conditional upon the amount of surface disturbance female sage-grouse were exposed to during reproductive stages. We quantified levels of exposure and compared them to the surface disturbance levels of the surrounding area. From 2008–2014, we collected data in 6 study areas in Wyoming, USA, containing 4 primary types of renewable and nonrenewable energy development. Our research focused on press disturbance (i.e., disturbance sustained after initial disturbance and associated with existing energy infrastructure and human activity). Our results suggest exposure to press disturbance during nesting and brood-rearing was related to lower nest and brood survival, which manifested at different spatial scales. Our analysis of nest survival suggested that the likelihood of a successful nest was negatively associated with the amount of press disturbance within an 8-km² area. Broods exposed to any press disturbance within a 1-km2 area were less likely to survive compared to broods not exposed to press disturbance. Female sage-grouse consistently used habitat with lower disturbance levels during reproductive periods. Greater than 90% of nest and brood-rearing locations were in habitat with <3% press disturbance within a 2.7-km2 area. Our research links surface disturbance associated with press disturbance to reproductive costs incurred by sage-grouse exposed to diverse energy development. Our results demonstrate a pattern of female avoidance of areas where press disturbance was high during nesting and brood-rearing and survival of nests and broods were highest in areas that had the least amount of disturbance. Our findings underscore the importance of minimizing disturbance to maintain viable sage-grouse populations. © 2020 The Wildlife Society.  相似文献   

8.
Abstract: Loss of quality brood rearing habitat, resulting in reduced chick growth and poor recruitment, is one mechanism associated with decline of greater sage-grouse (Centrocercus urophasianus) populations. Low chick survival rates are typically attributed to poor-quality brood rearing habitat. Models that delineate suitability of sage-grouse nesting or brood rearing habitat at the landscape scale can provide key insights into the relationship between sage-grouse and the environment, allowing managers to identify and prioritize habitats for protection or restoration. We used Southwest Regional Gap landcover types to identify early and late greater sage-grouse brood rearing in east-central Nevada. We conducted an Ecological Niche Factor Analysis to 1) examine the effect these landcover types and other ecogeographical variables have on sage-grouse selection of brood rearing habitat, and 2) generate landscape-scale suitability maps. We also evaluated if incorporating a fitness component (brood survival) in landscape spatial analyses of habitat quality influenced our assessment of habitat suitability. Because 36% of our 6,500-km2 study area was identified as early brood rearing habitat, we believe this habitat may not be limiting greater sage-grouse populations in east-central Nevada, USA, at least in wet years. We found strong selection for particular landcover types (e.g., higher elevation, moist sites with riparian shrubs or montane sagebrush) during late brood rearing. Late brood rearing habitat on which broods were successfully reared represented only 2.8% of the study area and had a restricted distribution, suggesting the potential that such habitat could limit sage-grouse populations in east-central Nevada.  相似文献   

9.
Greater sage-grouse (Centrocercus urophasianus) at the western edge of the Dakotas occur in the transition zone between sagebrush and grassland communities. These mixed sagebrush (Artemisia sp.) and grasslands differ from those habitats that comprise the central portions of the sage-grouse range; yet, no information is available on winter habitat selection within this region of their distribution. We evaluated factors influencing greater sage-grouse winter habitat use in North Dakota during 2005–2006 and 2006–2007 and in South Dakota during 2006–2007 and 2007–2008. We captured and radio-marked 97 breeding-age females and 54 breeding-age males from 2005 to 2007 and quantified habitat selection for 98 of these birds that were alive during winter. We collected habitat measurements at 340 (177 ND, 163 SD) sage-grouse use sites and 680 random (340 each at 250 m and 500 m from locations) dependent sites. Use sites differed from random sites with greater percent sagebrush cover (14.75% use vs. 7.29% random; P < 0.001), percent total vegetation cover (36.76% use vs. 32.96% random; P ≤ 0.001), and sagebrush density (2.12 plants/m2 use vs. 0.94 plants/m2 random; P ≤ 0.001), but lesser percent grass cover (11.76% use vs. 16.01% random; P ≤ 0.001) and litter cover (4.34% use vs. 5.55% random; P = 0.001) and lower sagebrush height (20.02 cm use vs. 21.35 cm random; P = 0.13) and grass height (21.47 cm use vs. 23.21 cm random; P = 0.15). We used conditional logistic regression to estimate winter habitat selection by sage-grouse on continuous scales. The model sagebrush cover + sagebrush height + sagebrush cover × sagebrush height ( = 0.60) was the most supported of the 13 models we considered, indicating that percent sagebrush cover strongly influenced selection. Logistic odds ratios indicated that the probability of selection by sage-grouse increased by 1.867 for every 1% increase in sagebrush cover (95% CI = 1.627–2.141) and by 1.041 for every 1 cm increase in sagebrush height (95% CI = 1.002–1.082). The interaction between percent sagebrush canopy cover and sagebrush height (β = −0.01, SE ≤ 0.01; odds ratio = 0.987 [95% CI = 0.983–0.992]) also was significant. Management could focus on avoiding additional loss of sagebrush habitat, identifying areas of critical winter habitat, and implementing management actions based on causal mechanisms (e.g., soil moisture, precipitation) that affect sagebrush community structure in this region. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.  相似文献   

10.
11.
ABSTRACT We estimated survival rates of 135 female greater sage-grouse (Centrocercus urophasianus) on 3 study areas in southeastern Oregon, USA during autumn and winter for 3 years. We used known-fate models in Program MARK to test for differences among study areas and years, investigate the potential influence of weather, and compute estimates of overwinter survival. We found no evidence for differences in survival rates among study areas, which was contrary to our original hypothesis. There also were no declines in survival rates during fall-winter, but survival rates varied among years and time within years. Average survival rate from October through February was 0.456 (SE = 0.062). The coefficient of variation for this estimate was 13.6% indicating good precision in our estimates of survival. We found strong evidence for an effect of weather (i.e., mean daily min. temp, extreme min. temp, snow depth) on bi-weekly survival rates of sage-grouse for 2 of the study areas in one year. Extremely low (<-15°C) temperatures over an 8-week period and accumulation of snow had a negative effect on survival rates during the winter of 1990–1991 on the 2 study areas at the higher (>1,500 m) elevations. In contrast, we found no evidence for an influence of weather on the low-elevation study area or during the winters of 1989–1990 and 1991–1992. Extreme weather during winter can cause lower survival of adult female sage-grouse, so managers should be aware of these potential effects and reduce harvest rates accordingly.  相似文献   

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ABSTRACT Nest predation is a natural component of greater sage-grouse (Centrocercus urophasianus) reproduction, but changes in nesting habitat and predator communities may adversely affect grouse populations. We used a 2-part approach to investigate sage-grouse nest predation. First, we used information criteria to compare nest survival models that included indices of common raven (Corvus corax) abundance with other survival models that consisted of day of incubation, grouse age, and nest microhabitat covariates using measurements from 77 of 87 sage-grouse nests. Second, we used video monitoring at a subsample of 55 of 87 nests to identify predators of depredated nests (n = 16) and evaluated the influence of microhabitat factors on the probability of predation by each predator species. The most parsimonious model for nest survival consisted of an interaction between day of incubation and abundance of common ravens (wravenXincubation day = 0.67). An estimated increase in one raven per 10-km transect survey was associated with a 7.4% increase in the odds of nest failure. Nest survival was relatively lower in early stages of incubation, and this effect was strengthened with increased raven numbers. Using video monitoring, we found the probability of raven predation increased with reduced shrub canopy cover. Also, we found differences in shrub canopy cover and understory visual obstruction between nests depredated by ravens and nests depredated by American badgers (Taxidea taxus). Increased raven numbers have negative effects on sage-grouse nest survival, especially in areas with relatively low shrub canopy cover. We encourage wildlife managers to reduce interactions between ravens and nesting sage-grouse by managing raven populations and restoring and maintaining shrub canopy cover in sage-grouse nesting areas.  相似文献   

15.
ABSTRACT Reduced annual recruitment because of poor habitat quality has been implicated as one of the causative factors in the range-wide decline of sage-grouse (Centrocercus urophasianus) populations since the 1950s. Because chick and brood survival are directly linked to annual recruitment and may be the primary factors that limit sage-grouse population growth, we estimated 28-day survival rates of radiomarked chicks and broods from 2000 to 2003. We examined relationships between survival and several habitat variables measured at brood sites, including food availability (insects and forbs); horizontal cover of sagebrush, grasses, and forbs; and vertical cover of sagebrush and grass. We monitored 506 radiomarked chicks from 94 broods; chick survival was 0.392 (SE = 0.024). We found evidence that both food and cover variables were positively associated with chick survival, including Lepidoptera availability, slender phlox (Phlox gracilis) frequency, total forb cover, and grass cover. The effect of total grass cover on chick survival was dependent on the proportion of short grass. The hazard of an individual chick's death decreased 8.6% (95% CI = −1.0 to 18.3) for each percentage point increase in total grass cover when the proportion of short grass was >70%. Survival of 83 radiomarked broods was 0.673 (SE = 0.055). Lepidoptera availability and slender phlox frequency were the only habitat variables related to brood survival. Risk of total brood loss decreased by 11.8% (95% CI = 1.2–22.5) for each additional Lepidoptera individual and 2.7% (95% CI = −0.4 to 5.8) for each percentage point increase in the frequency of slender phlox found at brood sites. Model selection results revealed that temporal differences in brood survival were associated with variation in the availability of Lepidoptera and slender phlox. Years with high brood survival corresponded with years of high Lepidoptera availability and high slender phlox frequency. These foods likely provided high-quality nutrition for chicks during early growth and development and enhanced survival. Habitat management that promotes Lepidoptera and slender phlox abundance during May and June (i.e., early brood rearing) should have a positive effect on chick and brood survival in the short term and potentially increase annual recruitment.  相似文献   

16.
Counts of greater sage-grouse (Centrocercus urophasianus) at leks have been used in harvest management, Endangered Species Act listing decisions, and land management policies for over half a century. Lek count sampling methods focus on counting male sage-grouse at known leks, primarily those observed visually from roads or vantage points, but leks are likely missed that are unknown prior to the survey and are difficult to detect while driving between known lek sites. One way to ameliorate this shortfall may be to conduct short point-count surveys at multiple stops along lek-survey routes or while driving between lek counts, thereby detecting newly established or unknown leks. To evaluate the feasibility of this approach, we estimated aural and visual detection probability of active sage-grouse leks during 1-minute point-count surveys at known distances and examined the effects of environmental factors on aural lek detection in southern Idaho, USA, 2016–2017. Our results demonstrate that field observers can aurally detect sage-grouse leks at approximately 3 times greater distances compared to detecting leks visually. The probability of hearing an active lek was highest near the peak of male and female attendance (8 Apr), within an hour of sunrise, on relatively calm and cold days, when the observer was at a higher elevation relative to the lek, and during conditions with no background noise. Detection probability declined with distance and the probability of aural detection was 0.59 at 1 km from a lek when other variables were held at their means. Hence, conducting ≥3 1-minute surveys along a lek route would be expected to detect ≥93% of all leks within 1.5 km of each survey under the average environmental conditions in our study. Our results suggest that surveys could greatly improve detection of unknown or newly established leks and can facilitate a more accurate assessment of sage-grouse population trends through lek counts. Moreover, our results demonstrate how environmental factors influence the detection of leks during surveys, and therefore which variables should be considered for inclusion in any future revisions of lek count protocols or in analyses of lek count data. © 2021 The Wildlife Society.  相似文献   

17.
Habitat loss is the most prevalent threat to biodiversity in North America. One of the most threatened landscapes in the United States is the sagebrush (Artemisia spp.) ecosystem, much of which has been fragmented or converted to non‐native grasslands via the cheatgrass‐fire cycle. Like many sagebrush obligates, greater sage‐grouse (Centrocercus urophasianus) depend upon sagebrush for food and cover and are affected by changes to this ecosystem. We investigated habitat selection by 28 male greater sage‐grouse during each of 3 years after a 113,000‐ha wildfire in a sagebrush steppe ecosystem in Idaho and Oregon. During the study period, seeding and herbicide treatments were applied for habitat restoration. We evaluated sage‐grouse responses to vegetation and post‐fire restoration treatments. Throughout the 3 years post‐fire, sage‐grouse avoided areas with high exotic annual grass cover but selected strongly for recovering sagebrush and moderately strongly for perennial grasses. By the third year post‐fire, they preferred high‐density sagebrush, especially in winter when sagebrush is the primary component of the sage‐grouse diet. Sage‐grouse preferred forb habitat immediately post‐fire, especially in summer, but this selection preference was less strong in later years. They also selected areas that were intensively treated with herbicide and seeded with sagebrush, grasses, and forbs, although these responses varied with time since treatment. Wildfire can have severe consequences for sagebrush‐obligate species due to loss of large sagebrush plants used for food and for protection from predators and thermal extremes. Our results show that management efforts, including herbicide application and seeding of plants, directed at controlling exotic annual grasses after a wildfire can positively affect habitat selection by sage‐grouse.  相似文献   

18.
Abstract Translocations of greater sage-grouse (Centrocercus urophasianus) have been attempted in 7 states and one Canadian province with very little success. To recover a small remnant population and test the efficacy of sage-grouse translocations, we captured and transported 137 adult female sage-grouse from 2 source populations to a release site in Strawberry Valley, Utah, USA, during March-April 2003–2005. The resident population of sage-grouse in Strawberry Valley was approximately 150 breeding birds prior to the release. We radiomarked each female and documented survival, movements, reproductive effort, flocking with resident grouse, and lek attendance. We used Program MARK to calculate annual survival of translocated females in the first year after release, which averaged 0.60 (95% CI = 0.515-0.681). Movements of translocated females were within current and historic sage-grouse habitat in Strawberry Valley, and we detected no grouse outside of the study area. Nesting propensity for first (newly translocated) and second (surviving) year females was 39% and 73%, respectively. Observed nest success of all translocated females during the study was 67%. By the end of their first year in Strawberry Valley, 100% of the living translocated sage-grouse were in flocks with resident sage-grouse. The translocated grouse attended the same lek as the birds with which they were grouped. In 2006, the peak male count for the only remaining active lek in Strawberry Valley was almost 4 times (135 M) the 6-year pretranslocation (1998–2003) average peak attendance of 36 males (range 24–50 M). Translocations can be an effective management tool to increase small populations of greater sage-grouse when conducted during the breeding season and before target populations have been extirpated.  相似文献   

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Detecting the disappearance of active leks is the most efficient way to determine large declines in greater sage-grouse (Centrocercus urophasianus) populations; thus, understanding factors that influence lek abandonment is critical. We evaluated factors that may have influenced the probability of sage-grouse lek abandonment in the Bighorn Basin (BHB) of north-central Wyoming from 1980 to 2009. Our objective was to examine lek abandonment based on landscape characteristics that explain differences between occupied and unoccupied leks. We evaluated lek abandonment from 144 occupied and 39 unoccupied leks from the Wyoming Game and Fish Department lek database with sufficient data for our 30-year analysis. We conducted our analysis with binary logistic regression using landscape predictor variables obtained from geographic coverages at 5 scales (1.0-, 3.2-, 4.0-, 5.0-, and 6.4-km radii around leks) to evaluate how these disturbances have influenced lek abandonment. Coverages included anthropogenic characteristics such as agricultural development, oil and gas development, prescribed burned treatments, and roads; and environmental characteristics such as vegetation attributes and wildfire. Our combined model included the number of oil and gas wells in a 1.0-km radius, percent area of wildfire in a 1.0-km radius, and variability in shrub height in a 1.0-km radius around sage-grouse leks. Abandoned (unoccupied) leks had 1.1-times the variability of shrub height in a 1.0-km radius, 3.1-times the percentage of wildfire in a 1.0-km radius, and 10.3-times the number of oil and gas wells in a 1.0-km radius compared to occupied leks. The model-averaged odds of lek persistence with every 1 unit increase in oil and gas wells within a 1.0-km radius was 0.66 (90% CI: 0.37–0.94), odds with every 1% increase in wildfire in a 1.0-km radius was 0.99 (90% CI: 0.85–1.12), and odds with every 1 unit increase in the standard deviation of shrub height within a 1.0-km radius around a lek was 0.77 (90% CI: 0.45–1.08). Because the 90% confidence intervals around the odds ratios of wells did not overlap 1.0, we suggest this predictor variable was most influential in our model-averaged estimates. The BHB has lower developed reserves of oil and gas than many other regions; however, our study supports findings from other studies that demonstrate energy development increases lek abandonment. Our findings indicate conservation efforts should be focused on minimizing well development and implementing wildfire suppression tactics near active sage-grouse leks. © 2012 The Wildlife Society.  相似文献   

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