| Parasites and Infectious Diseases of Greater Sage-Grouse. | Christiansen, Thomas J. | 2011 |
KeywordsCentrocercus urophasianus, disease, greater sage-grouse, parasite, pathogen AbstractWe report the parasites, infectious diseases, and noninfectious diseases related to toxicants found in Greater Sage-Grouse (Centrocercus urophasianus) across its range. Documentation of population-level effects is rare, although researchers have responded to the recent emergence of West Nile virus with rigorous efforts. West Nile virus shows greater virulence and potential population-level effects than any infectious agent detected in Greater Sage-Grouse to date. Research has demonstrated that (1) parasites and diseases can have population-level effects on grouse species; (2) new infectious diseases are emerging; and (3) habitat fragmentation is increasing the number of small, isolated populations of Greater Sage-Grouse. Natural resource management agencies need to develop additional research and systematic monitoring programs for evaluating the role of micro-and macro parasites, especially West Nile virus, infectious bronchitis and other corona viruses, avian retroviruses, Mycoplasma spp., and Eimeria spp. and associated enteric bacteria affecting sage-grouse populations. AuthorsChristiansen, Thomas J.; Tate, Cynthia M. Year Published2011 PublicationStudies in Avian Biology LocationsDOI10.1525/california/9780520267114.001.0001 |
| Comparison of Unmanned Aerial Vehicle Platforms for Assessing Vegetation Cover in Sagebrush Steppe Ecosystems | Breckenridge, Robert P. | 2011 |
Keywordsbare ground, fixed-wing, helicopter, landscape, monitoring, remote sensing AbstractIn this study, the use of unmanned aerial vehicles (UAVs) as a quick and safe method for monitoring biotic resources was evaluated. Vegetation cover and the amount of bare ground are important factors in understanding the sustainability of many ecosystems. Methods that improve speed and cost efficiency could greatly improve how biotic resources are monitored on western lands. Sagebrush steppe ecosystems provide important habitat for a variety of species including sage grouse and pygmy rabbit. Improved methods of monitoring these habitats are needed because not enough resource specialists or funds are available for comprehensive on-the-ground evaluations. In this project, two UAV platforms, fixed-wing and helicopter, were used to collect still-frame imagery to assess vegetation cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to 1) estimate percentage of cover for six different vegetation types (shrub, dead shrub, grass, forb, litter, and bare ground) and 2) locate sage grouse using representative decoys. The field plots were located on the Idaho National Laboratory site west of Idaho Falls, Idaho, in areas with varying amounts and types of vegetation cover. A software program called SamplePoint was used along with visual inspection to evaluate percentage of cover for the six cover types. Results were compared against standard field measurements to assess accuracy. The comparison of fixed-wing and helicopter UAV technology against field estimates shows good agreement for the measurement of bare ground. This study shows that if a high degree of detail and data accuracy is desired, then a helicopter UAV may be a good platform to use. If the data collection objective is to assess broad-scale landscape level changes, then the collection of imagery with a fixed-wing system is probably more appropriate. AuthorsBreckenridge, Robert P.; Dakins, Maxine; Bunting, Stephen; Harbour, Jerry L.; White, Sera Year Published2011 PublicationRangeland Ecology & Management LocationsDOI10.2111/REM-D-10-00030.1 |
| Comparing Ecological Site Descriptions to Habitat Characteristics Influencing Greater Sage-Grouse Nest Site Occurrence and Success | Doherty, Kevin E. | 2011 |
KeywordsCentrocercus urophasianus, landscape-scale habitat characteristics, local-scale habitat characteristics, nesting AbstractWe used 119 greater sage-grouse (Centrocercus urophasianus) nests located in the Powder River Basin of northeastern Wyoming during 2004-2007 to assess the ability of US Department of Agriculture Natural Resource Conservation Service (USDA-NRCS) ecological site descriptions (ESDs) to predict nest occurrence and success. We used nesting data from a regional study in the Powder River Basin that documented effects of local and landscape scale habitat characteristics on nest occurrence and success. We compared ESD metrics to these predictive local and landscape habitat variables where NRCS ESD field surveys overlapped our regional nest data set. We specifically asked three questions: 1) Are ESDs useful in predicting sage-grouse nest site occurrence and success as a univariate explanatory variable? 2) Can ESD information refine predictions of local scale nest site occurrence and success models? 3) Can ESD information refine landscape scale nest site occurrence models by serving as a surrogate for local scale information that cannot be mapped in a geographic information system (GIS)? Our results demonstrated that all models using ESD information were within +/- 2 Akaike's Information Criterion points of a constant only model (i.e., null model) for local-scale data, or a baseline model where local- and landscape-scale habitat metrics were held constant while allowing ESD models to compete for remaining variation. No ESD metrics were statistically significant at the 95% level (P < 0.05), although some were significant at the 80-90% level (P = 0.09-0.14). Our study does not support the use of ESDs to predict habitat use or base sage-grouse management decisions in the Powder River Basin, but in some instances the refutation was weak. Local and landscape based habitat metrics showed high discrimination between null models with highly significant relationships on the subset data. AuthorsDoherty, Kevin E.; Beck, Jeffrey L.; Naugle, David E. Year Published2011 PublicationRangeland Ecology & Management LocationsDOI10.2111/REM-D-10-00120.1 |
| Greater Sage-Grouse Movements and Habitat use during Winter in Central Oregon | Bruce, Jennifer R. | 2011 |
KeywordsNo keywords available AbstractGreater Sage-Grouse (Centrocercus urophasianus) depend on sagebrush habitat for food and cover during winter, yet few sage-grouse winter ecology studies have been conducted. During January and February 2007, we monitored 22 radio-collared sage-grouse (7 females and 15 males) in central Oregon to characterize winter habitat use and movement patterns. We estimated distances traveled between locations on a weekly basis and quantified habitat characteristics at locations used by male and female sage-grouse. The birds we collared moved extensively across the landscape, using approximately 1480 km(2). Sagebrush canopy height in sites used by sage-grouse varied from 0.25 to 0.75 m, with females tending to be found in sites with taller sagebrush and less foliar cover than ill sites where we found males. The difference in foliar cover between sexes was related to a seasonal change in habitat use: 4 females found in little sagebrush (Artemisia arbuscula) in January and early February were no longer located nor found foraging in little sagebrush after 15 February. Also, by this date, most male sage-grouse had stopped using big sagebrush (Artemisia tridentate) as they migrated to leks. Sage-grouse mortality rates were low during our study which May be attributed to the study area receiving half the long-term average amount of snow. The large area over which sage-grouse moved during winter indicates that conservation of Greater Sage-Grouse may require preservation of sagebrush at landscape scales (thousands of square kilometers). AuthorsBruce, Jennifer R.; Robinson, W. Douglas; Petersen, Steven L.; Miller, Richard F. Year Published2011 PublicationWestern North American Naturalist LocationsDOI10.3398/064.071.0310 |
| Habitat Selection by Greater Sage-Grouse During Winter in Southeastern Oregon | Hagen, Christian A. | 2011 |
KeywordsNo keywords available AbstractThe distribution and geographic range of Greater Sage-Grouse (Centrocercus urophasianus) have been reduced by 56% since European settlement. Although loss and fragmentation of sagebrush (Artemisia spp.) habitats have been cited as the primary causes for the decline of the species, degradation of existing habitat also has been considered an important factor. Guidelines for protection and management of breeding and winter habitat have been developed for land managers, but winter habitat use has not been thoroughly described throughout the species range, particularly for the western portion of its range in Oregon. We examined vegetation-type selection and use by Greater Sage-Grouse during winter (Nov-Feb) at 3 study areas in southeastern Oregon (1989-1992). Elevation gradients and vegetative communities differed among these 3 areas. Our objective was to examine the geographic variation in the selection and use of various vegetation types during winter; when sage-grouse distributions may be most restricted. We described differences in vegetation structure at the microhabitat scale among 3 areas and differences in vegetation-type selection at the macrohabitat scale. We found that the use of mixed sagebrush (basin big sagebrush Artemisia tridentata tridentata]) and other shrubby vegetation types by sage-grouse was greater than expected at all 3 study areas. At the low- and high-elevation study areas, low sagebrush (Artemisia longiloba) vegetation types were selected more often than expected at random, which was contrary to our original hypotheses. Basin big sagebrush vegetation types were used in proportion to their availability at the 2 low-elevation study areas, and big sagebrush steppe was used less than available (avoided) at the low-elevation areas; these results were contrary to our original predictions. Such differences in selection among the study areas in southeastern Oregon create additional challenges for land managers, who are charged with managing habitats for sage-grouse use during autumn and winter in this portion of the species' geographic range. AuthorsHagen, Christian A.; Willis, Mitchell J.; Glenn, Elizabeth M.; Anthony, Robert G. Year Published2011 PublicationWestern North American Naturalist LocationsDOI10.3398/064.071.0411 |
| Collection and comparison of natural ejaculates and sperm morphometrics of greater (Centrocercus urophasianus) and gunnison sage-grouse (C. minimus). | Hicks, Tyler L. | 2011 |
Collection and comparison of natural ejaculates and sperm morphometrics of greater (Centrocercus urophasianus) and gunnison sage-grouse (C. minimus).KeywordsNo keywords available AbstractIn spring 2008, we collected four natural ejaculates from strutting male Greater (Galliformes: Centrocercus urophasianus) and Gunnison Sage-Grouse (C. minimus) in Colorado, USA by placing freeze-dried female Greater Sage-Grouse on leks in the soliciting pre-copulatory position and fitting them with false cloacas. We compared between species the sperm concentrations, the percentage of viable sperm, the types and predominance of normal and abnormal sperm in ejaculate samples, and sperm morphometric traits. In addition, we compared sperm concentration and morphometry of both species with other species of Galliformes. Notwithstanding our small sample size, ejaculate characteristics were similar among individuals and between the two grouse species. Total length did not differ substantially between the two species. However, we found that Greater Sage-Grouse possess sperm heads that averaged 10% longer than those of Gunnison Sage-Grouse and Gunnison Sage-Grouse possess sperm tails that averaged 10% longer than those of Greater Sage-Grouse. Total sperm length in both species is among the smallest known for Galliformes. Compared to other Galliformes, sperm concentration was low for Gunnison Sage-Grouse and average for Greater Sage-Grouse. AuthorsHicks, Tyler L.; Magee, Patrick A. Year Published2011 PublicationColorado Birds Locations |
| Greater Sage-Grouse: General Use and Roost Site Occurrence with Pellet Counts as a Measure of Relative Abundance | Hanser, S.E. | 2011 |
Greater Sage-Grouse: General Use and Roost Site Occurrence with Pellet Counts as a Measure of Relative AbundanceKeywordsNo keywords available AbstractGreater sage-grouse (Centrocercus
urophasianus) have been declining
both spatially and numerically throughout their range because of anthropogenic disturbance and loss and fragmentation of sagebrush (Artemisia spp.) habitats. Understanding
how sage-grouse respond to
these habitat alterations and disturbances,
particularly the types of disturbances
and extent at which they respond, is critical
to designing management actions and
prioritizing areas of conservation. To address
these needs, we developed statistical
models of the relationships between
occurrence and abundance of greater
sage-grouse and multi-scaled measures
of vegetation, abiotic, and disturbance in the Wyoming Basins Ecoregional Assessment (WBEA) area. Sage-grouse occurrence was strongly related to the amount of sagebrush within 1 km for both roost site and general use locations. Roost sites were identified by presence of sage-grouse
fecal pellet groups whereas general use
locations had single pellets. Proximity to
anthropogenic disturbance including energy development, power lines, and major roads was negatively associated with sagegrouse occurrence. Models of sage-grouse occurrence correctly predicted active lek locations with >75% accuracy. Our spatially explicit models identified areas of high occurrence probability in the WBEA area that can be used to delineate areas for conservation and refine existing conservation
plans. These models can also facilitate
identification of pathways and corridors
important for maintenance of sage-grouse population connectivity. AuthorsHanser, S. E., C. L. Aldridge, M. Leu, M. M. Rowland, S. E. Nielsen, and S. T. Knick Year Published2011 PublicationSagebrush Ecosystem Conservation and Management LocationsAdditional Information:http://sagemap.wr.usgs.gov/Docs/WBEA/wbea_chap_5_sagegrouse_2mb.pdf |
| Yearling Greater Sage-Grouse Response to Energy Development in Wyoming. | HOLLORAN, MATTHEW J. | 2010 |
KeywordsCentrocercus urophasianus;energy development;greater sage-grouse;sage-grouse;Wyoming;yearling AbstractSagebrush (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. AuthorsHOLLORAN, MATTHEW J., RUSTY C. KAISER and WAYNE A. HUBERT. Year Published2010 PublicationJournal of Wildlife Management LocationsDOI10.2193/2008-291 |
| Nest Predation of Greater Sage-Grouse in Relation to Microhabitat Factors and Predators. | COATES, PETER S. | 2010 |
KeywordsAmerican badger;Centrocercus urophasianus;common raven;greater sage-grouse;nest predation;video monitoring AbstractNest 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 (wraven×incubation 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. AuthorsCOATES, PETER S. and DAVID J. DELEHANTY. Year Published2010 PublicationJournal of Wildlife Management LocationsDOI10.2193/2009-047 |
| Assessing Compensatory Versus Additive Harvest Mortality: An Example Using Greater Sage-Grouse. | SEDINGER, JAMES S. | 2010 |
KeywordsCentrocercus urophasianus;compensatory harvest;exploitation;Markov chain Monte Carlo;survival AbstractWe used band-recovery data from 2 populations of greater sage-grouse (Centrocercus urophasianus), one in Colorado, USA, and another in Nevada, USA, to examine the relationship between harvest rates and annual survival. We used a Seber parameterization to estimate parameters for both populations. We estimated the process correlation between reporting rate and annual survival using Markov chain Monte Carlo methods implemented in Program MARK. If hunting mortality is additive to other mortality factors, then the process correlation between reporting and survival rates will be negative. Annual survival estimates for adult and juvenile greater sage-grouse in Nevada were 0.42 ± 0.07 (x ¯ ± SE) for both age classes, whereas estimates of reporting rate were 0.15 ± 0.02 and 0.16 ± 0.03 for the 2 age classes, respectively. For Colorado, average reporting rates were 0.14 ± 0.016, 0.14 ± 0.010, 0.19 ± 0.014, and 0.18 ± 0.014 for adult females, adult males, juvenile females, and juvenile males, respectively. Corresponding mean annual survival estimates were 0.59 ± 0.01, 0.37 ± 0.03, 0.78 ± 0.01, and 0.64 ± 0.03. Estimated process correlation between logit-transformed reporting and survival rates for greater sage-grouse in Colorado was ? = 0.68 ± 0.26, whereas that for Nevada was ? = 0.04 ± 0.58. We found no support for an additive effect of harvest on survival in either population, although the Nevada study likely had low power. This finding will assist mangers in establishing harvest regulations and otherwise managing greater sage-grouse populations. AuthorsSEDINGER, JAMES S., GARY C. WHITE, SHAWN ESPINOSA, ED T. PARTEE and CLAIT E. BRAUN. Year Published2010 PublicationJournal of Wildlife Management LocationsDOI10.2193/2009-071 |
