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Filters: Tags: human impacts (X) > partyWithName: U.S. Geological Survey - ScienceBase (X) > partyWithName: Shawn T O'Neil (X)

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These tables serve as input data for hierarchical models investigating interactions between raven density and Greater Sage-grouse nest success. Observations were recorded over an 11 year time period, spanning from 2009 through 2019. The model is run in JAGS via R, the code is publicly available via the U.S. Geological Survey's GitLab (O'Neil et al. 2023). We recommend not making any changes or edits to the tables unless the user is experienced with hierarchical modeling. References: O'Neil, S.T., Coates, P.S., Webster, S.C., Brussee, B.E., Dettenmaier, S.J., Tull, J.C., Jackson, P.J., Casazza, M.L., and Espinosa, S.P., 2023, Code for a hierarchical model of raven densities linked with sage-grouse nest survival...
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We used a hierarchical Bayesian modeling framework to estimate resource selection functions and survival for early and late brood-rearing stages of sage-grouse in relation to a broad suite of habitat characteristics evaluated at multiple spatial scales within the Great Basin from 2009 to 2019. Sage-grouse selected for greater perennial grass cover, higher relative elevations, and areas closer to springs and wet meadows during both early and late brood-rearing. Terrain characteristics, including heat load and aspect, were important in survival models, as was variation in shrub height. We also found strong evidence for higher survival for both early and late broods within previously burned areas, but survival within...
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Ranked habitat classes for sage-grouse brood-rearing productivity at each 90 m pixel. Habitat classes represent areas where high brood selection and high brood survival intersected, whereas the lowest ranks represent areas where high brood habitat selection intersected with the low brood survival. Hierarchical models of brood selection and survival were fit to landscape covariates within a Bayesian modeling framework in Nevada and California from 2009 - 2017 to develop spatially explicit information about brood habitat selection and survival.
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We evaluated the expected success of habitat recovery in priority areas under 3 different restoration scenarios: passive, planting, and seeding. Passive means no human intervention following a fire disturbance. Under a planting scenario, field technicians methodically plant young sagebrush saplings at the burned site. The seeding scenario involves distributing large amounts of sagebrush seeds throughout the affected area.
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Predictions of raven occurrence in the absence of anthropogenic environmental effects. Raven point counts were related to landscape covariates using Bayesian hierarchical occupancy models and the means of the posterior distributions for relevant effects were used to generate the predictions.
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We evaluated brood-rearing habitat selection and brood survival of greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) in Long Valley, California, an area where the water rights are primarily owned by the city of Los Angeles and water is used locally to irrigate for livestock. This area thus represents a unique balance between the needs of wildlife and people that could increasingly define future water management. In this study, sage-grouse broods moved closer to the edge of mesic areas and used more interior areas during the late brood-rearing period, selecting for greener areas after 1 July. Mesic areas were particularly important during dry years, with broods using areas farther interior than...
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We evaluated nest site selection and nest survival both before and after a fire disturbance occurred. We then combined those surfaces to determine the areas which were most heavily impacted by the fire.
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These data represent habitat selection of greater sage-grouse at the 50 day mark of their brood rearing process. Sage-grouse and their broods were monitored on their own individual time lines, so one group's 50th day may not necessarily be the same as any other bird's 50th day.
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Predictions of raven occurrence in the absence of natural environmental effects. Raven point counts were related to landscape covariates using Bayesian hierarchical occupancy models and the means of the posterior distributions for relevant effects were used to generate the predictions.
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We monitored Greater Sage-Grouse (Centrocercus urophasianus; hereafter, Sage-Grouse) nests and various habitat characteristics at the nest locations near Susanville in northeastern California, crossing over into northwestern Nevada. We employed a before-after-control-impact (BACI) experimental design to account for spatiotemporal heterogeneity in the system and to derive estimates of relative change in survival parameters. Sage-Grouse nest survival decreased after the Rush Fire but decreased more in the burned area relative to the unburned area. Although female Sage-Grouse continued to occupy burned areas, nest survival was reduced from 52 percent to 19 percent. Using a BACI ratio approach we found that nest survival...
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Rasters representing median raven density estimates, calculated from approximately 28,000 raven point count surveys conducted between 2009 and 2019. Estimates were the result of a Bayesian hierarchical distance sampling model, using environmental covariates on detection and abundance.
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Expanding human enterprise across remote environments impacts many wildlife species, including sage-grouse (Centrocercus urophasianus), an indicator species whose decline is at the center of national conservation strategies and land use policies. Anthropogenic resources provide subsidies for generalist predators, potentially leading to cascading effects on sensitive prey species at lower trophic levels. In semi-arid western ecosystems, common ravens (Corvus corax) are expanding in distribution and abundance, and may be negatively affecting sage-grouse reproductive success at broad spatial scales. Ravens are a common predator of sage-grouse nests, and potentially prey on chicks as well. This research aimed to address...
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A hierarchical occupancy model adapted from Royle & Dorazio (2008) and Rota et al. (2011) for use in R. References: Royle, J.A. and Dorazio, R.M., 2008. Hierarchical modeling and inference in ecology: the analysis of data from populations, metapopulations and communities. Academic Press. doi:10.1016/B978-0-12-374097-7.50001-5 J. Andrew Royle, Robert M. Dorazio, Rota, C. T., Fletcher Jr, R. J., Dorazio, R. M. and Betts, M. G. (2009), Occupancy estimation and the closure assumption. Journal of Applied Ecology, 46: 1173-1181. doi:10.1111/j.1365-2664.2009.01734.x
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We combined approximately 28,000 raven point count surveys with data from more than 900 sage-grouse nests between 2009 and 2019 within the Great Basin, USA. We modeled variation in raven density using a Bayesian hierarchical distance sampling approach with environmental covariates on detection and abundance. Concurrently, we modeled sage-grouse nest survival using a hierarchical frailty model as a function of raven density as well as other environmental covariates that influence risk of failure. Raven density commonly exceeded more than 0.5 ravens per square kilometer and increased at low relative elevations with prevalent anthropogenic development and/or agriculture. Reduced sage-grouse nest survival was strongly...
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Sage-grouse continue to use habitat following wildfire, so prioritizing high selection, low survival areas can help ameliorate potential post-wildfire ecological traps. This shapefile represents areas within the burn scars at the Virginia Mountains field site which are high selection and high or low survival which have been deemed to be 'priority' targets for post-fire restoration efforts. The 'burn scar' used in this project is an amalgamation of multiple fires which occurred within the field site during the summers of 2016 and 2017.


map background search result map search result map Data from: Broad-scale occurrence of a subsidized avian predator: reducing impacts of ravens on sage-grouse and other sensitive prey Raven study site locations in the Great Basin, derived from survey locations 2007 - 2016 Predictions of raven occurrence in the absence of natural environmental effects in the Great Basin, 2007-2016 (Fig. 4A) Predictions of raven occurrence in the absence of anthropogenic environmental effects in the Great Basin, 2007-2016 (Fig. 4B) Prediction of raven occurrence intersected with high impact areas for sage-grouse populations in the Great Basin, 2007-2016 (Fig. 5A) Hierarchical Occupancy Model Code for R and Accompanying Files Greater Sage-Grouse Nest Observations Before and After Wildfire Disturbance in Northeastern California (2007-2018) Spatially-Explicit Predictive Maps of Greater Sage-Grouse Brood Selection Integrated with Brood Survival in Nevada and Northeastern California, USA Habitat Suitability Index for Greater Sage-Grouse 50 Days into the Brood Rearing Life Stage, Nevada and California Habitat Suitability Index for Greater Sage-Grouse During the Late Brood Rearing Life Stage, Nevada and California Ranked Habitat Classes for Sage-Grouse Brood-Rearing Productivity, Nevada and California Greater Sage-Grouse Relative Survival During the Early Brood Rearing Life Stage, Nevada and California Greater Sage-Grouse Relative Survival During the Late Brood Rearing Life Stage, Nevada and California Sagebrush Restoration Under Passive, Planting, and Seeding Scenarios Following Fire Disturbance in the Virginia Mountains, Nevada (2018) Post-Fire Change in Greater Sage-Grouse Nest Selection and Survival in the Virginia Mountains, Nevada (2018) Priority Areas for Habitat Restoration Post-Fire in the Virginia Mountains, Nevada (2018) Selection and Survival of Greater Sage-Grouse Broods in Mesic Areas of Long Valley, California (2003 - 2018) Data to Support Hierarchical Models and Decision Support Maps to Guide Management of Subsidized Avian Predator Densities Median Estimates of Raven Density in California, Nevada, and Idaho (2012 - 2019) Raven Observations near Greater Sage-Grouse Nests in the Great Basin and Bi-State Regions of the Western United States (2009 - 2019) Selection and Survival of Greater Sage-Grouse Broods in Mesic Areas of Long Valley, California (2003 - 2018) Priority Areas for Habitat Restoration Post-Fire in the Virginia Mountains, Nevada (2018) Post-Fire Change in Greater Sage-Grouse Nest Selection and Survival in the Virginia Mountains, Nevada (2018) Sagebrush Restoration Under Passive, Planting, and Seeding Scenarios Following Fire Disturbance in the Virginia Mountains, Nevada (2018) Greater Sage-Grouse Nest Observations Before and After Wildfire Disturbance in Northeastern California (2007-2018) Data to Support Hierarchical Models and Decision Support Maps to Guide Management of Subsidized Avian Predator Densities Median Estimates of Raven Density in California, Nevada, and Idaho (2012 - 2019) Spatially-Explicit Predictive Maps of Greater Sage-Grouse Brood Selection Integrated with Brood Survival in Nevada and Northeastern California, USA Habitat Suitability Index for Greater Sage-Grouse 50 Days into the Brood Rearing Life Stage, Nevada and California Habitat Suitability Index for Greater Sage-Grouse During the Late Brood Rearing Life Stage, Nevada and California Ranked Habitat Classes for Sage-Grouse Brood-Rearing Productivity, Nevada and California Greater Sage-Grouse Relative Survival During the Early Brood Rearing Life Stage, Nevada and California Greater Sage-Grouse Relative Survival During the Late Brood Rearing Life Stage, Nevada and California Raven Observations near Greater Sage-Grouse Nests in the Great Basin and Bi-State Regions of the Western United States (2009 - 2019) Raven study site locations in the Great Basin, derived from survey locations 2007 - 2016 Prediction of raven occurrence intersected with high impact areas for sage-grouse populations in the Great Basin, 2007-2016 (Fig. 5A) Hierarchical Occupancy Model Code for R and Accompanying Files Data from: Broad-scale occurrence of a subsidized avian predator: reducing impacts of ravens on sage-grouse and other sensitive prey Predictions of raven occurrence in the absence of natural environmental effects in the Great Basin, 2007-2016 (Fig. 4A) Predictions of raven occurrence in the absence of anthropogenic environmental effects in the Great Basin, 2007-2016 (Fig. 4B)