| Energy development affects populations of sagebrush songbirds in Wyoming. | Gilbert, Michelle M. | 2011 |
Keywordsavian abundance;Brewer's sparrow;natural gas;oil;sage sparrow;sage thrasher;shrubsteppe;species richness AbstractOil and natural gas development in the Intermountain West region of North America has expanded over the last 2 decades, primarily within sagebrush dominated landscapes. Although the effects of energy development on high-profile game species such as the greater sage-grouse (Centrocercus urophasianus) have been documented, studies examining responses of non-game birds are lacking. Simultaneously, many songbirds that breed within sagebrush steppe habitats have shown range-wide population declines that are likely due to widespread habitat loss and alteration. We evaluated songbird abundance and species richness across gradients of oil and natural gas development intensity, as indexed by well density, at 3 energy fields (2 natural gas and 1 oil) in the Upper Green River Basin, Wyoming, USA during 2008-2009. While simultaneously accounting for important habitat attributes, increased well density was associated with significant decreases in Brewer's sparrow (Spizella breweri) and sage sparrow (Amphispiza belli) abundance, particularly in the Jonah natural gas field. Vesper sparrows (Pooecetes gramineus) were also negatively influenced by increased well density. Horned larks (Eremophila alpestris) increased with well density in the Pinedale Anticline natural gas field, and sage thrashers (Oreoscoptes montanus) showed no response to energy development. Species richness was not significantly affected by well density. Results suggest that regional declines of some songbird species, especially sagebrush-obligates, may be exacerbated by increased energy development. Understanding the specific mechanisms underlying responses to energy development is an important next step and will aid land managers in the development of effective mitigation and management strategies for the maintenance of stable bird communities in sagebrush habitat. © 2011 The Wildlife Society. AuthorsGilbert, Michelle M. and Anna D. Chalfoun. Year Published2011 PublicationJournal of Wildlife Management LocationsDOI10.1002/jwmg.123 |
| Survival of Greater Sage-Grouse Chicks and Broods in the Northern Great Basin. | GREGG, MICHAEL A. | 2009 |
Keywordsbrood;Centrocercus urophasianus;chick;forbs;greater sage-grouse;insects;Lepidoptera;radiotelemetry;survival AbstractReduced 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. AuthorsGREGG, MICHAEL A. and JOHN A. CRAWFORD. Year Published2009 PublicationJournal of Wildlife Management LocationsDOI10.2193/2007-410 |
| 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 |
| Sage-Grouse Habitat Selection During Winter in Alberta. | Carpenter, Jennifer | 2010 |
KeywordsCentrocercus urophasianus;critical habitat;energy development;greater sage-grouse;resource selection functions;winter habitats AbstractGreater 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. AuthorsCarpenter, Jennifer, Cameron Aldridge and Mark S. Boyce. Year Published2010 PublicationJournal of Wildlife Management LocationsDOI10.2193/2009-368 |
| Silver Sagebrush Community Associations in Southeastern Alberta, Canada. | Jones, Paul F | 2005 |
Keywordsdistribution ; greater sage-grouse ; height ; occupancy ; site AbstractGreater sage-grouse (Centrocercus urophasianus) habitat in southeastern Alberta is limited by the distribution of silver sagebrush (Artemisia cana Pursh). We conducted a landscape assessment of silver sagebrush throughout the current range of sage-grouse in southeastern Alberta. Black-and-white aerial photography acquired in the fall of 2001 was used to map silver sagebrush. Contact print stereo pairs were interpreted using a stereoscope and initially classified into 1 of 13 site classes based on soil type and landscape feature (e.g., recent agriculture). Each site polygon was further broken down into smaller polygons based on the percentage of silver sagebrush occupancy, density distribution, and height. A total of 4626 site polygons were identified and classed into 1 of 13 site classes. To ensure all assumptions of statistical tests were met, the data set was reduced to 9 site classes. The mean percentage of silver sagebrush occupancy was significantly different between the 9 site classes (F=... AuthorsPaul F Jones, Roy Penniket, Livio Fent, Joel Nicholson, Barry Adams Year Published2005 PublicationRangeland Ecology & Management LocationsDOI10.2111/1551-5028(2005)058[0400:SSCAIS]2.0.CO;2 |
| Interspace/Undercanopy Foraging Patterns of Beef Cattle in Sagebrush Habitats. | France, Kevin A | 2008 |
Keywordsbunchgrass ; forage selection ; grazing behavior ; ground nesting birds ; sage-grouse AbstractForage selection patterns of cattle in sagebrush (Artemisia L.) communities are influenced by a variety of environmental and plant-associated factors. The relative preference of cattle for interspace versus under-sagebrush canopy bunchgrasses has not been documented. Potential preferences may indirectly affect habitat for sage-grouse and other ground-nesting birds. Our objectives were to investigate grazing patterns of cattle with respect to undercanopy (shrub) and interspace tussocks, determine the influence of cattle grazing on screening cover, and relate shrub morphology to undercanopy grazing occurrence. Eighteen-day replicated trials were conducted in the summers of 2003 and 2004. Findings suggest cattle initially concentrate grazing on tussocks between shrubs, and begin foraging on tussocks beneath shrubs as interspace plants are depleted. Grazing of undercanopy grass tussocks was negligible at light-to-moderate utilization levels ( < 40% by weight). Grass tussocks under spreading, umbrella-shaped shrub canopies were less likely (P < 0.001) to be grazed than those beneath erect, narrow canopies. Horizontal screening cover decreased (P < 0.001) with pasture utilization. At the trial's end, removal of 75% of the herbaceous standing crop induced about a 5% decrease in screening cover in all strata from ground level to 1 m with no differences among strata (P = 0.531). This implied that shrubs constituted the majority of screening vegetation. Our data suggest that conservative forage use, approaching 40% by weight, will affect a majority (about 70%) of interspace tussocks and a lesser proportion (about 15%) of potential nest-screening tussocks beneath sagebrush. Probability of grazing of tussocks beneath shrubs, however, is also affected by shrub morphology. These findings will help managers design grazing programs in locales where habitat for ground nesting birds is a concern. AuthorsKevin A France, Dave Ganskopp, Chad S Boyd Year Published2008 PublicationRangeland Ecology & Management LocationsDOI10.2111/06-072.1 |
| Timing of Vegetation Sampling at Greater Sage-Grouse Nests. | Hausleitner, Doris | 2005 |
KeywordsCentrocercus urophasianus ; Colorado ; nest site selection ; nest initiation AbstractHabitat management guidelines for greater sage-grouse, Centrocercus urophasianus, have been formulated, in part, based on studies of nest site selection. However, these guidelines may not represent conditions when the female initiates nesting because sampling occurs posthatch (> 30 days after nest initiation) to avoid disturbing incubating females. In 2002, we investigated differences in 22 habitat variables at initiation and hatch. Sampling was at 30 randomly selected active nests marked in 2001. There was no significant difference in structural or cover data (P > 0.05). Grass height and percent grass cover differed (P < 0.05) based on timing of sampling. Grass heights at the nest bowl and at 1 m from the edge of the nest bowl were 10 and 9 cm at initiation and 16 and 13 cm at hatch, respectively. Percent grass cover increased from 4% to 6% cover from initiation to hatch. Sampling occurred in a dry year; differences in grass heights and percent cover may be more pronounced in years of normal precipitation. Preliminary results indicated current habitat sampling techniques conducted posthatching adequately described selection of structural components of shrub height, visual obstruction, and percent cover of shrubs, bare ground, litter, and forbs at the nest site at initiation. Data need to be verified for other study areas and under different climatic conditions. AuthorsDoris Hausleitner, Kerry P Reese, Anthony D Apa Year Published2005 PublicationRangeland Ecology & Management LocationsDOI10.2111/04-170R2.1 |
| Using human-imprinted chicks to evaluate the importance of forbs to sage-grouse | Huwer, Sherri L. | 2008 |
Keywordsbrood habitat; Centrocercus urophasianus; Colorado; forb; growth; habitat; imprinting; sage-grouse AbstractAlthough several studies have indicated the importance of forbs in brood habitats, no studies have quantified direct effects of the amount of forb cover on sage-grouse (Centrocercus urophasianus) chicks. In 2002 and 2003, we conducted field experiments in Middle Park and Moffat County, Colorado, USA, respectively. Our objective was to quantify effects of 3 levels of forb cover in brood habitat on mass gain and feather growth of human-imprinted sage-grouse chicks. The results indicate that increasing forb cover in brood areas with <20% forb cover may lead to increased chick survival and grouse productivity. AuthorsHuwer, Sherri L.; Anderson, David R.; Remington, Thomas E.; White, Gary C. Year Published2008 PublicationJournal of Wildlife Management LocationsDOI10.2193/2004-340 |
