Search

On the Ground • A recent publication by Carter et al. (2017) presents research on the effects of deferred rotation grazing and water provisioning on a suite of environmental variables. • We detail issues that call into question the validity of the results and conclusions reported by the authors. • Data were not collected in a scientifically rigorous way. • Sufficient detail is not presented for the study to be replicated. • The authors do not adhere to standard statistical definitions or assumptions. • The study suffers from unaccounted for pseudoreplication. • The authors draw conclusions beyond the reasonable scope of inference.

Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agriculture's Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Grasshopper Sparrow (Ammodramus savannarum), and Henslow's Sparrow (A. henslowii), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslow's Sparrow nest density w...

Range-wide declines of greater sage-grouse (Centrocercus urophasianus; sage-grouse) populations have been attributed to long-term habitat alteration and fragmentation. In areas that still exhibit suitable habitats and where population declines have been attributed to other threats (e.g., invasive predators), managers have successfully used translocations to augment declining wildlife populations. However, translocations to augment sage-grouse populations have had limited success and the relative contribution of translocated sage-grouse to declining populations is not well understood. From 2009 to 2012 we studied the vital rates of 34 resident (21 yearlings and 13 adults) and 60 translocated radio-marked female sage-grouse (30 yearlings and 30 adults) on Anthro Mountain in northeastern Utah, USA to determine the relative contributions of each group to population productivity. We used the encounter histories of the monitored sage-grouse to construct nest survival models for program MARK to assess the impacts of age and residency status on annual survival and overall reproductive success in the population. Annual survival was not affected by age or residency status and averaged 0.40 (95% CI = 0.31–0.50). The yearling newly translocated females (translocated females during their first yr in the release area) exhibited the lowest nest initiation rates (0.50, 95% CI = 0.30–0.69), whereas adult resident and previously translocated (translocated females that survived ≥1 yr in the release area) females had the highest nest initiation (0.96, 95% CI = 0.88–0.99). Overall nest success (0.43, 95% CI = 0.30–0.55) and brood success (0.55, 95% CI = 0.41–0.69) were not affected by residency status or age. The adult resident and previously translocated females exhibited the highest overall reproductive success (0.22, 95% CI = 0.14–0.31) followed by resident yearling females (0.20, 95% CI = 0.12–0.29), and newly translocated adult females (0.18, 95% CI = 0.10–0.27). Newly translocated yearling females had the lowest overall reproductive success (0.12, 95% CI = 0.05–0.18). Survival of adult females is a major factor influencing sage-grouse population stability. Although adult and yearling newly translocated females had similar survival rates, adult translocated females were more likely to raise a brood in their first year in the release area. Thus, managers should consider translocating a higher ratio of adult to yearling females in future translocation efforts to see a more immediate effect on population growth in the release area. However, because of the low vitals rates recorded in our study, managers should identify and mitigate the limiting factors affecting the resident population prior to implementing a translocation to augment declining populations. © 2017 The Wildlife Society.

The influence of harvest on wild populations has been the focus of substantial debate, and has widespread implications for the management of wild populations. Traditional views of harvest are based on density-dependent responses of populations to harvest. However, alternate mechanisms can and do induce compensation (e.g., individual heterogeneity). Selective harvest of successful females and their offspring is thought to occur in some grouse populations (e.g., blue grouse [Dendragapus spp.], greater sage-grouse [Centrocercus urophasianus]), and delaying harvest within a season has been proposed as a viable strategy to overcome this type of selective harvest. However, a recent examination regarding the effects of harvest on greater sage-grouse strongly criticized the recommendation of delayed harvest. Herein, we address the criticism of the delayed harvest strategy and provide an examination of projecting the effects of harvest in the face of individual heterogeneity using deterministic projection models. We demonstrate that under proportional harvesting strategies, given a fixed harvest rate, early additive harvest does not have a larger effect on the population than additive harvest later in the season. Moreover, we show that when higher quality individuals (i.e., individuals with higher survival and reproductive rates) are more susceptible to harvest, individual heterogeneity in harvest effects will induce depensatory dynamics when density-dependent effects are only additive. Conversely, even when density-dependent effects are additive, if lower quality individuals are more susceptible to harvest, heterogeneity will induce partial compensation. Reducing the selectivity of harvest on higher quality individuals (i.e., shifting harvest onto lower quality groups) could reduce the risk of artificial selection and induce partial compensation. Therefore, we recommend managers consider the spatiotemporal patterns of populations and time harvest to maximize the heterogeneity tradeoff between higher and lower quality individuals. © 2017 The Wildlife Society.

A potential consequence of climate change, altered fire regimes, and a legacy of resource exploitation in western North America is increased displacement of desirable sagebrush (Artemisia spp.) communities by invasive plant species. Annually, an estimated 90,000 ha of sage-grouse (Centrocercus spp.) habitat is degraded by pinyon (Pinus spp.) and juniper (Juniperus spp.; PJ) encroachment. Sage-grouse responses to conifer encroachment may include avoidance of otherwise available habitats, lek abandonment, and subsequent population declines. Thus, restoration of PJ encroached sage-grouse habitats that exhibit intact sagebrush understories is a priority conservation action. However, better information is needed regarding sage-grouse response to these management actions. We used sage-grouse fecal pellet surveys and radiotelemetry location data to identify vegetation and landscape attributes that may influence sage-grouse use of PJ removal treatments completed using mechanical methods. Use of PJ removal treatments by sage-grouse was positively associated with irrigated pasture and alfalfa (Medicago sativa) hay within 1 km (β = 7.69, SE = 5.58, P = 0.17) and negatively associated with PJ canopy cover (β = −1.52, SE = 0.84, P = 0.07) within 500 m of treatments. Percent cover of mesic habitats and sagebrush canopy were greater within 1 km of treatments where sage-grouse were detected; however, these relationships were weak because of large variability in conditions across sites. Our results document sage-grouse use of 9 of 16 mechanical PJ removal treatments examined in an encroached sagebrush landscape and suggest that mechanical PJ removal treatments should be sited adjacent to occupied sage-grouse habitat in areas that minimize surrounding PJ cover. © 2017 The Wildlife Society.

[This corrects the article DOI: 10.1371/journal.pone.0209968.].

Collisions between vehicles and wildlife have long been recognized to pose threats to motorists and wildlife populations. In addition to the risk of injury or mortality faced by the motorists involved in wildlife-vehicle collisions (WVCs), other drivers are also put at risk due to road obstructions and traffic congestions associated with WVCs. Most WVCs in Alaska involve moose (Alces alces), an animal that is sufficiently large to pose a threat to property and human life when involved in collisions. We analyzed the temporal variation in the number of moose–vehicle collisions (MVCs) reported in the 4 most populous boroughs of Alaska, USA from 2000–2012. We examined daily and annual trends in MVC rates and compared them to moose and human behavioral patterns to better understand possible mitigation strategies. The distribution of MVCs was skewed toward winter and hours of the day with less visibility. Fifty percent of the MVCs reported from 2000–2012 occurred where the commuter rush hours overlapped with dusk and dawn in winter. Knowledge of these temporal patterns can provide managers with practical mitigation options, such as the use of seasonal speed reduction, improved lighting strategies, dynamic signage, or partnerships with mobile mapping services.

Beyond the recognized importance of protecting large areas of contiguous habitat, conservation efforts for many species are complicated by the fact that patch suitability may also be affected by characteristics of the landscape within which the patch is located. Currently, little is known about the spatial scales at which species respond to different aspects of the landscape surrounding an occupied patch. Using grassland bird point count data, we describe an approach to evaluating scale-specific effects of landscape composition on patch occupancy. We used data from 793 point count surveys conducted in idle and grazed grasslands across Wisconsin, USA from 2012 to 2014 to evaluate scale-dependencies in the response of grassland birds to landscape composition. Patch occupancy models were used to evaluate the relationship between occupancy and landscape composition at scales from 100 to 3000 m. Bobolink (Dolichonyx oryzivorus) exhibited a pattern indicating selection for grassland habitats in the surrounding landscape at all spatial scales while selecting against other habitats. Eastern Meadowlark (Sturnella magna) displayed evidence of scale sensitivity for all habitat types. Grasshopper Sparrow (Ammodramus savannarum) showed a strong positive response to pasture and idle grass at all scales and negatively to cropland at large scales. Unlike other species, patch occupancy by Henslow’s Sparrow (A. henslowii) was primarily influenced by patch area. Our results suggest that both working grasslands (pasture) and idle conservation grasslands can play an important role in grassland bird conservation but also highlight the importance of considering species-specific patch and landscape characteristics for effective conservation.

Translocations have been recommended to reestablish, augment, and sustain genetic diversity in declining wildlife populations, including greater sage-grouse (Centrocercus urophasianus; sage-grouse). Characteristics of successful sage-grouse translocations include suitable contiguous sagebrush (Artemisia spp.), seasonal habitats surrounded by geomorphic barriers, a residual resident population, and pre-nesting releases. From 2009 to 2010, we studied vital rates of 60 translocated and 15 resident radio-marked female sage-grouse and their broods on Anthro Mountain, in the Ashley National Forest, northeastern Utah, USA to determine whether translocations could augment a declining meta-population that inhabited suitable breeding habitats in a small spatially isolated landscape. Survival rates, and nest and brood success estimates for the resident and translocated sage-grouse we studied were lower than reported range-wide averages. Nest success was similar for resident and translocated birds (survival estimate: 0.468, 95% CI = 0.288–0.648) and we calculated weak, yet positive relationships to grass height and grass cover. Daily survival rates for chicks 0–19 days of age for resident females in 2009 (0.904, CI = 0.875–0.940) and in 2010 (0.910, CI = 0.888–0.945) were higher than for chicks raised by translocated females (0.883, CI = 0.850–0.915; 0.892, CI = 0.856–0.936, respectively), although differences were small and all 95% confidence intervals had substantial overlap. In 2009 and 2010, daily survival rates for chick 20–50 days of age were slightly higher for chicks reared by resident females (0.980, CI = 0.963–0.994; 0.998, CI = 0.978–1.000, respectively) than chicks reared by translocated females (0.877, CI = 0.623–0.959; 0.988, CI = 0.945–0.993, respectively). Chick survival for both groups was weakly correlated with grass cover. Although most translocated birds remained on the study area (82%), the low overall survival rates we report indicate that managers need to consider factors affecting survival of adult females, nests, and chicks when planning future translocations to augment sage-grouse meta-populations that occupy spatially isolated and space-limited habitats. © 2016 The Wildlife Society.

As a hunted species becomes increasingly rare, the effort required to locate and harvest an individual tends to increase. As rarity increases, governmental oversight, including changes in hunting regulations and protection of habitats and individuals using mechanisms such as the US Endangered Species Act (ESA), can be used to mitigate extinction risks. However, recent research has demonstrated the existence of a feedback mechanism through which increased rarity may increase hunter demand for opportunities to pursue rare species before the opportunity is lost. This phenomenon, referred to as the anthropogenic Allee effect, may exacerbate exploitation, thereby resulting in disproportionally large effects of harvest on vulnerable species. In 2010, the US Fish and Wildlife Service designated greater sage-grouse (Centrocercus urophasianus; sage-grouse) as a candidate for listing under the ESA. Although sage-grouse are a candidate for ESA listing, they are still hunted throughout much of their current range. In 2008, the demand for sage-grouse hunting permits in Utah exceeded their availability, raising questions about why hunters choose to pursue this species. We hypothesized that the pending ESA listing decision increased hunter demand for permits. We surveyed randomly selected hunters who obtained permits to hunt sage-grouse in Utah in 2008–2010 (n = 838) to determine their motivations for hunting sage-grouse and determinants of hunter satisfaction. The most commonly reported reasons for hunting sage-grouse were to spend time with family, for tradition and meat. Although the potential ESA listing was not a major motivational factor in 2009 or 2010, the percentage of respondents selecting this option did increase by 7%. Hunter awareness of the ESA listing petition also increased by 18% during this period. Our results provide new insights on the sociological importance and potential threats of hunting rare species.

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) adult hen and juvenile survival have been shown to have significant influence on population growth rates. However, assessing the sensitivity of population growth rates to variability in juvenile survival has proven difficult because of limited information concerning the potentially important demographic rate. Sage-grouse survival rates are commonly assessed using necklace-type radio transmitters. Recent technological advances have lead to increased interest in the deployment of dorsally mounted global positioning system (GPS) transmitters for studying sage-grouse ecology. However, the use of dorsally mounted transmitters has not been thoroughly evaluated for sage-grouse, leading to concern that birds fitted with these transmitters may experience differentialmortality rates. Weevaluated theeffect oftransmitter positioning(dorsal vs.necklace) on juvenile sage-grouse survival using a controlled experimental design with necklace-style and suture-backpack very high frequency (VHF) transmitters. To evaluate theeffects oftemporalvariation, sex, andtransmitter type on juvenile sage-grouse survival, we monitored 91 juveniles captured in south-central Utah from 2008 to 2010. We instrumented 19 females with backpacks, 14 males with backpacks, 39 females with necklaces, and 19 males with necklaces. We used Program MARK to analyze juvenile survival data. Although effects were only marginally significant from a statistical perspective, sex (P ¼0.103) and transmitter type (P ¼0.09) were deemed to have biologically meaningful impacts on survival. Dorsally mounted transmitters appeared to negatively affected daily survival (btransmitter type ¼� 0.55, SE ¼0.32). Temporal variation in juvenile sage- grouse daily survival was best described by a quadratic trend in time, where daily survival was lowest in late September and was high overwinter. An interaction between the quadratic trend in time and year resulted in the low point of daily survival shifting within the season between years (27 vs. 17 Sep for 2008 and 2009, respectively). Overall (15 Aug-31 Mar) derived survival ranged 0.42-0.62 for females and 0.23-0.44 for males. For all years pooled, the probability death was due to predation was 0.73, reported harvest was 0.16, unreported harvest was 0.09, and other undetermined factors was 0.02. We observed 0% and 6.8% crippling loss (from hunting) in 2008 and 2009, respectively. We recommend the adoption of harvest management strategies that attempt to shift harvest away from juveniles and incorporate crippling rates. In addition, future survival studies on juvenile sage-grouse should use caution if implementing dorsally mounted transmitters because of the potential for experimental bias. 2014 The Wildlife Society.

Anthropogenic infrastructure can negatively affect wildlife through direct mortality and/or displacement behaviors. Some tetranoids (grouse spp.) species are particularly vulnerable to tall anthropogenic structures because they evolved in ecosystems void of vertical structures. In western North America, electric power transmission and distribution lines (power lines) occur in sagebrush (Artemisia spp.) landscapes within the range of the greater sage-grouse (Centrocercus urophasianus; sage-grouse). The U.S. Fish and Wildlife Service recommended using buffer zones near leks to mitigate the potential impacts of power lines on sage-grouse. However, recommended buffer distances are inconsistent across state and federal agencies because data are lacking. To address this, we evaluated the effects of power lines on sage-grouse breeding ecology within Utah, portions of southeastern Idaho, and southwestern Wyoming from 1998-2013. Overall, power lines negatively affected lek trends up to a distance of 2.7 and 2.8 km, respectively. Power lines died not affect lek persistence. Female sage-grouse avoided transmission lines during the nesting and brooding seasons at distances up to 1.1 and 0.8 km, respectively. Nest and brood success were negatively affected by transmission lines up to distances of 2.6 and 1.1 km, respectively. Distribution lines did not appear to affect sage-grouse habitat selection or reproductive fitness. Our analyses demonstrated the value of sagebrush cover in mitigating potential power line impacts. Managers can minimize the effects of new transmission power lines by placing them in existing anthropogenic corridors and/or incorporating buffers at least 2.8 km from active leks. Given the uncertainty we observed in our analyses regarding sage-grouse response to distribution lines coupled with their role in providing electric power service directly to individual consumers, we recommend that buffers for these power lines be considered on a case-by-case basis. Micrositing to avoid important habitats and habitat reclamation may reduce the potential impacts of new power line construction.

Greater sage-grouse (Centrocercus urophasianus; sage-grouse) are a species of conservation concern throughout western North America. Obtaining valid population estimates is essential to understanding population trajectories and the effects of management. Counts of male sage-grouse attending leks during the breeding season are used directly as a population index or to estimate the breeding population size by assuming a detection probability and sex ratio. In the latter case, managers often assume a 2:1 female-biased ratio. However, this sex ratio has not been validated and may result in biased population estimates. We evaluated sex ratios at hatch, 42 days of age, and at harvest to determine if sex ratios were biased for sage-grouse in Utah. Sex ratios at hatch and at 42 days of age did not differ from parity. Harvest data suggested that sage-grouse may exhibit a slight female-biased sex ratio (1.458:1) in the fall. Wildlife management agencies should use caution when using lek count data to estimate population size if sex ratios have not been validated. © 2013 The Wildlife Society.

Sagebrush (Artemisia spp.) constitutes the majority (>99%) of sage-grouse (Centrocercus spp.) winter diets. Thus, identification and protection of important winter habitats is a conservation priority. However, not all sagebrush may be alike. More information is needed regarding sage-grouse sagebrush winter dietary preferences for application to management. The objective of our research was to determine if chemical analysis of fecal pellets could be used to characterize winter sage-grouse diets as a substitute for more invasive methods. We collected and analyzed fecal pellets and sagebrush samples from 29 different sage- grouse flock locations in northwestern and southcentral Utah. Using gas chromatography, we were able to identify crude terpene profiles that were unique to Wyoming sagebrush (A. tridentata wyomingensis) and black sagebrush (A. nova). We subsequently used the profiles to determine sagebrush composition of sage- grouse fecal pellets, thus reflecting sage-grouse winter diets. This technique provides managers with a tool to determine which species or subspecies of sagebrush may be important in the winter diets of sage-grouse populations. 2011 The Wildlife Society.

Bottomland hardwood forests of the United States have drastically declined since European settlement. Although much of the reported loss has resulted from conversion to agriculture and urban development, thousands of additional hectares have been degraded due to selective harvesting and a lack of effort to establish desirable regeneration prior to harvesting. Research has indicated that seedlings of some oak species perform best with intermediate levels of light, while performing less desirably at both high and low levels. This study demonstrates that controlling undesirable midstory trees through herbicide injection alone can be sufficient to create suitable light conditions for oak regeneration in some circumstances. We were able to increase the average percentage of total available light to 31.5% (SE = 0.029) as compared to only 14.2% (SE = 0.011) in untreated areas (F1,33 = 46.57, p < .0001). Additionally, oak seedlings planted in areas receiving midstory control exhibited good to excellent survival c...

Obtaining timely and accurate assessment of sage-grouse (Centrocercus spp.) chick survival and recruit- ment is an important component of species management and conservation. We compared the effectiveness of walking, spotlight, and pointing-dog surveys to detect radio-marked and unmarked chicks within broods of radio-marked hens in Utah. Walking surveys detected 72% of marked chicks, while spotlight and pointing-dog surveys detected 100% and 96%, respectively. We found no difference between spotlight and pointing-dog counts in number of marked and unmarked chicks detected (P = 0.57). Spotlight counts were slightly more time efficient than pointing-dog surveys. However, spotlight surveys were nocturnal searches and perceived to be more technically arduous than diurnal point- ing-dog surveys. Pointing-dog surveys may offer greater utility in terms of area searched per unit effort and an increased ability to detect unmarked hens and broods.

Species conservation efforts often use short‐term studies that fail to identify the vital rates that contribute most to population growth. Although the greater sage‐grouse (Centrocercus urophasianus; sage‐grouse) is a candidate for protection under the U.S. Endangered Species Act, and is sometimes referred to as an umbrella species in the sagebrush (Artemisia spp.) biome of western North America, the failure of proposed management strategies to focus on key vital rates that may contribute most to achieving population stability remains problematic for sustainable conservation. To address this dilemma, we performed both prospective and retrospective perturbation analyses of a life cycle model based on a 12‐yr study that encompassed nearly all sage‐grouse vital rates. To validate our population models, we compared estimates of annual finite population growth rates (λ) from our female‐based life cycle models to those attained from male‐based lek counts. Post‐fledging (i.e., after second year, second year, and juvenile) female survival parameters contributed most to past variation in λ during our study and had the greatest potential to change λ in the future, indicating these vital rates as important determinants of sage‐grouse population dynamics. In addition, annual estimates of λ from female‐based life cycle models and male‐based lek data were similar, providing the most rigorous evidence to date that lek counts of males can serve as a valid index of sage‐grouse population change. Our comparison of fixed and mixed statistical models for evaluating temporal variation in nest survival and initiation suggest that conservation planners use caution when evaluating short‐term nesting studies and using associated fixed‐effect results to develop conservation objectives. In addition, our findings indicated that greater attention should be paid to those factors affecting sage‐grouse post‐fledging females. Our approach demonstrates the need for more long‐term studies of species vital rates across the life cycle. Such studies should address the decoupling of sampling variation from underlying process (co)variation in vital rates, identification of how such variation drives population dynamics, and how decision makers can use this information to re‐direct conservation efforts to address the most limiting points in the life cycle for a given population.

Effective long-term wildlife conservation planning for a species must be guided by information about population vital rates at multiple scales. Greater sage-grouse (Centrocercus urophasianus) populations declined substantially during the twentieth century, largely as a result of habitat loss and fragmentation. In addition to the importance of conserving large tracts of suitable habitat, successful conservation of this species will require detailed information about factors affecting vital rates at both the population and range-wide scales. Research has shown that sage-grouse population growth rates are particularly sensitive to hen and chick survival rates. While considerable information on hen survival exists, there is limited information about chick survival at the population level, and currently there are no published reports of factors affecting chick survival across large spatial and temporal scales. We analyzed greater sage-grouse chick survival rates from 2 geographically distinct populations across 9 years. The effects of 3 groups of related landscape-scale covariates (climate, drought, and phenology of vegetation greenness) were evaluated. Models with phenological change in greenness (NDVI) performed poorly, possibly due to highly variable production of forbs and grasses being masked by sagebrush canopy. The top drought model resulted in substantial improvement in model fit relative to the base model and indicated that chick survival was negatively associated with winter drought. Our overall top model included effects of chick age, hen age, minimum temperature in May, and precipitation in July. Our results provide important insights into the possible effects of climate variability on sage-grouse chick survival.

Research on long-lived iteroparous species has shown that reproductive success may increase with age, until the onset of senescence, and that prior reproductive success may influence current reproductive success. Such complex reproductive dynamics can complicate conservation strategies, especially for harvested species. Further complicating the matter is the fact that most studies of reproductive costs are only able to evaluate a single measure of reproductive effort. We systematically evaluated the effects of climatic variation and reproductive trade-offs on multiple reproductive vital rates for greater sage-grouse (Centrocercus urophasianus; sage-grouse), a relatively long-lived galliforme of conservation concern throughout western North America. Based on over a decade of field observations, we hypothesized that reproduction is influenced by previous reproductive success. We monitored hen reproductive activity from 1998 to 2010, and used generalized linear mixed models to assess effects of climate and previous reproductive success on subsequent reproductive success. Reproductive trade-offs manifested as chronic effects on subsequent reproduction and were not apparent in all measures of subsequent reproduction. Neither nest initiation nor clutch size were found to be affected by climatic variables (either year t - 1 or t) or previous reproductive success. However, both nest and brood success were affected by climatic variation and previous reproductive success. Nest success was highest in years with high spring snowpack, and was negatively related to previous brood success. Brood success was positively influenced by moisture in April, negatively associated with previous nest success, and positively influenced by previous brood success. Both positive and negative effects of previous reproduction on current year reproduction were observed, possibly indicating high levels of individual heterogeneity in female reproductive output. Our results support previous research in indicating that climatic variability may have significant negative impacts on reproductive rates.