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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   

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Abstract: We studied greater sage-grouse (Centrocercus urophasianus) in northcentral Montana, USA, to examine the relationship between nest success and habitat conditions, environmental variables, and female sage-grouse characteristics. During 2001-2003, we radiomarked 243 female greater sage-grouse, monitored 287 nests, and measured 426 vegetation plots at 4 sites in a 3,200-km2 landscape. Nest survival varied with year, grass canopy cover, daily precipitation with a 1-day lag effect, and nesting attempt. In all years, daily survival rate increased on the day of a rain event and decreased the next day. There was temporal variation in nest success both within and among years: success of early (first 28 d of nesting season) nests ranged from 0.238 (SE = 0.080) in 2001 to 0.316 (SE = 0.055) in 2003, whereas survival of late (last 28 d of nesting season) nests ranged from 0.276 (SE = 0.090) in 2001 to 0.418 (SE = 0.055) in 2003. Renests experienced higher survival than first nests. Grass cover was the only important model term that could be managed, but direction and magnitude of the grass effect varied. Site, shrub and forb canopy cover, and Robel pole reading were less useful predictors of nest success; however, temporal and spatial variation in these habitat covariates was low during our study. We note a marked difference between both values and interpretations of apparent nest success, which have been used almost exclusively in the past, and maximum-likelihood estimates used in our study. Annual apparent nest success (0.46) was, on average, 53% higher than maximum-likelihood estimates that incorporate individual, environmental, and habitat covariates. The difference between estimates was variable (range = +8% to +91%). Management of habitats for nesting sage-grouse should focus on increasing grass cover to increase survival of first nests and contribute to favorable conditions for renesting, which should be less likely if survival of first nests increases.  相似文献   

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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   

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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   

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ABSTRACT A new high-voltage transmission line in north-central Nevada, USA, was considered a potential threat to greater sage-grouse (Centrocercus urophasianus) because avian predators are attracted to and hunt from elevated perches. As a mitigation measure, perch deterrents were installed on the transmission line towers at the time of construction; in addition, 2 existing high-voltage transmission lines were retrofitted with deterrents. Previous published studies have investigated the efficacy of perch deterrents in preventing or reducing electrocution of avian predators and fecal contamination of insulators, but none have evaluated deterrents as a means of eradicating perching on towers. We conducted point transect surveys and perching-duration observations of corvids and raptors and determined that although perch deterrents did not prevent perching, the perching duration of raptors on the deterrents was reduced compared to other perching substrates. Perching of raptors indicated that some hunting most likely took place from the towers; therefore, the deterrents did not completely obviate the threat that avian predators posed to greater sage-grouse. Although the deterrents reduced the probability of avian predators perching on the towers, avian predators overcame the deterrents to take advantage of the height of the towers where no other perches of similar height existed. The perch deterrents as designed did not have the desired short-term effect on avian predators, but further monitoring may reveal longer-term effects and distinguish perching behaviors specific to different species of avian predators.  相似文献   

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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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Translocation is a vital tool in conservation and recovery programs, and knowledge of factors that determine demographic rates of translocated organisms is important for assessing the efficacy of translocations. Greater sage-grouse (Centrocercus urophasianus) have been the subject of recent translocation efforts because of their declining range and their usefulness as an umbrella species for conservation. Using a long-term data set on sage-grouse in central Washington, USA, we compared movement and demographic rates of translocated and resident birds. Because newly translocated birds experience physiological stress during translocation and are released in unfamiliar habitat, we hypothesized their demographic rates would differ from residents. We analyzed 18 years of radio-tracking data acquired from resident, newly translocated (<1 yr post-translocation; T1), and previously translocated (>1 yr post-translocation; T2) sage-grouse between 1989 and 2017 to estimate movement rates, survival, and productivity. Newly translocated sage-grouse exhibited farther daily movements (0.58 km/day) and smaller 95% home ranges (89 km2) than residents and previously translocated birds. Daily movements and sex influenced survival, but survival did not differ according to residency status. Furthermore, birds that survived to a second year after translocation exhibited shorter daily movements compared to their first year ( = −0.727 ± 0.157 [SE]), which corresponded with increased survival the second year (T1 = 0.526, T2 = 0.610). This decrease in movements and increase in survival the second year was not apparent in the control group of resident birds, indicating a possible behavioral link to survival of newly translocated sage-grouse. Most productivity metrics were similar for translocated and resident birds, except for nest propensity (i.e., nest initiation rate), which was lower for newly translocated birds (35%) compared to residents and previously translocated birds. Our results reveal that translocated sage-grouse exhibit temporary differences in some demographic parameters in their first year, which later align with those of resident birds in subsequent years. Similarities in adult and nest survival according to residency status further suggest that translocation may prove to be a viable tool for restoring and conserving this species. Continued declines in sage-grouse populations in Washington, however, indicate that habitat conversion and fragmentation may be reducing demographic rates of residents and translocated birds, which warrants further study. © 2019 The Wildlife Society.  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   

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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   

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Survival of greater sage-grouse (Centrocercus urophasianus) has been well described in large populations across the species range. Very little published information exists, however, on survival rates of translocated sage-grouse or grouse from a long-term (>10 yr) study. Our objectives were to estimate seasonal and annual survival rates; assess differences in survival between resident and translocated, adult and yearling, and male and female sage-grouse; identify environmental and behavioral factors associated with survival; and assess the influence of mammalian predator control on survival rates of radio-marked sage-grouse in Strawberry Valley, Utah from 1998 to 2010. We used a 2-stage model selection approach using Akaike's Information Criterion corrected for sample size (AICc) with known-fate models in Program MARK to evaluate the influences of seasonal, annual, demographic, and behavioral effects on survival rates of sage-grouse. We captured and fitted 535 individual sage-grouse (male and female, resident and translocated) with radio transmitters over a 13-year period and monitored them weekly. The top model of survival, which accounted for 22% of the AICc weight, included 3 seasons that varied by year where rates were influenced by residency, sex, and whether a female initiated a nest. A group-level covariate for the number of canids killed each year received some support as this variable improved model fit compared to identical models without it, although confidence intervals around β estimates overlapped zero slightly. All other demographic or environmental variables showed little or no support. Annual estimates of survival for females ranged between 28% and 84% depending on year and translocation source. Survival was consistently highest during the fall–winter months with a mean monthly survival rate of 0.97 (95% CI = 0.96–0.98). The lack of a control site and other potential confounding factors limit the extent of our inference with respect to predator control. Nonetheless, we suggest managers consider enhancing nesting habitat, translocating sage-grouse, and possibly controlling predators to improve survival rates of sage-grouse. © The Wildlife Society, 2013  相似文献   

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We used female ring-necked pheasant (Phasianus colchicus) carcasses as surrogates for greater sage-grouse (Centrocercus urophasianus) to study factors influencing survival and detection bias associated with avian fence collision surveys in southern Idaho, USA, during spring 2009. We randomly placed 50 pheasant carcasses on each of 2 study areas, estimated detection probability during fence-line surveys, and monitored survival and retention of carcasses and their associated sign over a 31-day period. Survival modeling suggested site and habitat features had little impact on carcass survival, and constant survival models were most supported by the data. Model averaged carcass daily survival probability was low on both study areas and ranged from 0.776 to 0.812. Survival of all carcass sign varied strongly by location, and the top sign survival model included a site effect parameter. Model averaged daily survival probability for collision sign on the 2 study sites ranged from 0.863 to 0.988 and varied between sites. Logistic regression modeling indicated detection probability of carcasses during fence-line surveys for avian collision victims was influenced by habitat type and microsite shrub height at the carcass location. Carcasses located in big sagebrush (Artemisia tridentata) habitats were detected at a lower rate (0.36) than carcasses in little (A. arbuscula) and black sagebrush (A. nova) habitats (0.71). Increasing shrub height at the carcass location from the little sagebrush mean of 16.5 cm to the big sagebrush mean of 36.0 cm reduced detection probability by approximately 30%. Avian fence collision surveys in sagebrush-steppe habitats should be conducted at ≤2-week sampling intervals to reduce the impact of survival bias on collision rate estimates. Two-week sampling intervals may be too long in areas with low carcass and sign survival, therefore survival rates should be estimated on all study areas to determine the appropriate sampling interval duration. Researchers should be aware of the effects of local vegetation on detection probabilities, and methods to correct detection probabilities based on collision site attributes should be applied to ensure more accurate collision rate estimates. Additionally, caution should be used when aggregating or comparing uncorrected collision data from areas with differing vegetation, as detection probabilities are likely different between sites. © 2011 The Wildlife Society.  相似文献   

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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   

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Sage-grouse (Centrocercus spp.) 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 Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.  相似文献   

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