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Melanism (dark coloration) is a condition resulting from a greater than normal expres-sion of the eumelanin pigments in the plumage (Gill 1990). The dark coloration can be advantageous to raptors by increasing the feathers’ resistance to bacterial degradation (Goldstein et al. 2004). conversely, abnormally dark pigmentation can reduce success in pairing by disguising key species-identification cues (García 2003) and decrease lifetime reproductive success by increasing mortality (krüger and lindström 2001). Polymorphism in color, of which melanism is one example, occurs in at least 3.5% of avian species worldwide and in 22% of raptors of the family Accipitridae (harriers, hawks, eagles, kites, and Old World vultures;...
The spread and impacts of exotic species are unambiguous, global threats to many ecosystems. A prominent example is the suite of annual grasses in the Bromus genus (Bromus hereafter) that originate from Europe and Eurasia but have invaded or are invading large areas of the Western USA. This book brings a diverse, multidisciplinary group of authors together to synthesize current knowledge, research needs, and management implications for Bromus. Exotic plant invasions are multifaceted problems, and understanding and managing them requires the biological, ecological, sociological, and economic perspectives that are integrated in this book. Knowing how well information from one geographic or environmental setting can...
A genecological approach was used to explore genetic variation for survival in Artemisia tridentata (big sagebrush). Artemisia tridentata is a widespread and foundational shrub species in western North America. This species has become extremely fragmented, to the detriment of dependent wildlife, and efforts to restore it are now a land manage-ment priority. Common- garden experiments were established at three sites with seed-lings from 55 source- populations. Populations included each of the three predominant subspecies, and cytotype variations. Survival was monitored for 5 years to assess dif-ferences in survival between gardens and populations. We found evidence of adap-tive genetic variation for survival. Survival...
Abstract (from http://link.springer.com/article/10.1007%2Fs10980-015-0160-1): Content Changing aspen distribution in response to climate change and fire is a major focus of biodiversity conservation, yet little is known about the potential response of aspen to these two driving forces along topoclimatic gradients. Objective This study is set to evaluate how aspen distribution might shift in response to different climate-fire scenarios in a semi-arid montane landscape, and quantify the influence of fire regime along topoclimatic gradients. Methods We used a novel integration of a forest landscape succession and disturbance model (LANDIS-II) with a fine-scale climatic water deficit approach to simulate dynamics of...
Although biotic responses to contemporary climate change are spatially pervasive and often reflect synergies between climate and other ecological disturbances, the relative importance of climatic factors versus habitat extent for species persistence remains poorly understood. To address this shortcoming, we performed surveys for American pikas (Ochotona princeps) at > 910 locations in 3 geographic regions of western North America during 2014 and 2015, complementing earlier modern (1994–2013) and historical (1898–1990) surveys. We sought to compare extirpation rates and the relative importance of climatic factors versus habitat area for pikas in a mainland-versus-islands framework. In each region, we found widespread...
Bromus tectorum (cheatgrass) has widely invaded the Great Basin, U.S.A. The sporadic natural phenomenon of complete stand failure (‘die- off’) of this invader may present opportunities to restore native plants. A recent die-off in Nevada was precision-planted with seeds of the native grasses Poa secunda (Sandberg bluegrass) and Elymus elymoides (bottlebrush squirreltail), of both local and nonlocal origin, to ask: 1) Can native species be restored in recent B. tectorum die-offs? And 2) Do local and nonlocal seeds differ in performance? Additionally, we asked how litter removal and water addition affected responses. Although emergence and growth of native seeds was lower in die-off than control plots early in year...
We examined patterns of genetic variation and diversity of extant pygmy rabbit (Brachylagus idahoensis) populations across the species’ current range in Nevada and California. Our aims were to determine population genetic structure and levels of diversity across the southern portion of the species’ range. We genotyped 13 microsatellite loci from 194 fecal samples collected across 14 localities. Our Bayesian cluster analyses found 2 genetically distinct groups: 1 in the Mono Basin of California and the other encompassing all remaining Nevada Great Basin populations. Considering only the Nevada Great Basin group, we found 4 minimally divergent groups that overlap spatially with many individuals maintaining composite...
Land managers in the Great Basin are working to maintain or restore sagebrush ecosystems as climate change exacerbates existing threats. Web applications delivering climate change and climate impacts information have the potential to assist their efforts. Although many web applications containing climate information currently exist, few have been co-produced with land managers or have incorporated information specifically focused on land managers’ needs. Through surveys and interviews, we gathered detailed feedback from federal, state, and tribal sagebrush land managers in the Great Basin on climate information web applications targeting land management. We found that a) managers are searching for weather and climate...
Characterizing circadian activity patterns is one of the essential steps to understanding how a species interacts with its environment. This study documented activity patterns of pygmy rabbits (Brachylagus idahoensis) in free-ranging populations at 5 sites in Nevada and California. Infrared-triggered camera systems were placed within areas occupied by populations of pygmy rabbits and operated for 1 year. The number of photographs obtained per hour was used as an index of aboveground activity. Activity was analyzed for diel and seasonal patterns as well as for differences among populations. All populations showed a bimodal diel activity pattern with most activity occurring at dawn and at dusk during all seasons....
Conservation Biology Institute (CBI) has been developing web applications to centralize and serve credible and usable information that allows natural resource managers, as well as the general public, to better understand the challenges posed by on-going environmental change. In particular CBI has designed a series of climate consoles that provide natural resource managers the most recent 5th Climate Model Intercomparison Program (CMIP5) climate projections, landscape intactness, and soil sensitivity for a series of reporting units over the western United States. The publically available web sites were refined based on feedback from a variety of users. In this paper, we describe each of the tools developed as open-source...
Rising temperatures have begun to shift flowering time, but it is unclear whether phenotypic plasticity canaccommodate projected temperature change for this century. Evaluating clines in phenological traits and the extentand variation in plasticity can provide key information on assessing risk of maladaptation and developing strategiesto mitigate climate change. In this study, flower phenology was examined in 52 populations of big sagebrush (Artemi-sia tridentata) growing in three common gardens. Flowering date (anthesis) varied 91 days from late July to lateNovember among gardens. Mixed-effects modeling explained 79% of variation in flowering date, of which 46% couldbe assigned to plasticity and genetic variation...
The loss of big sagebrush (Artemisia tridentata Nutt.) on sites disturbed by fire has motivated restoration seeding and planting efforts. However, the resulting sagebrush establishment is often lower than desired, especially in dry areas. Sagebrush establishment may be increased by addressing factors such as seed source and condition or management of the plant community. We assessed initial establishment of seeded sagebrush and four populations of small outplants (from different geographies, climates, and cytotypes) and small sagebrush outplants in an early seral community where mowing, herbicide, and seeding of other native plants had been experimentally applied. No emergence of seeded sagebrush was detected. Mowing...
The phenomenon of cheatgrass die-off is a common and naturally- occurring stand failure that can eliminate the presence of this annual grass for a year or more, affecting tens to hundreds of thousands of acres in some years. We designed a study to determine if the temporary lack of cheatgrass caused by die-offs is a restoration opportunity. We seeded native perennial species at three die-offs in the Winnemucca, Nevada area. Native grass establishment in die-offs was almost three times higher in the first season at all sites, relative to adjacent areas without die-off. In the second season, establishment was five times higher in the die-off at two sites, and plants were notably larger in the die-off at the third...
Three main folders are associated with this readme file. They are: 1. "Files", which contains two subfolders, "Dieoffs" and "PercentCover". a) The "Dieoff" subfolder contains every year's modeled cheatgrass dieoff estimates and their associated files, including a layer file. The dieoff estimates’ file format is ERDASImagine signed 16-bit. Values < -100 are underperforming relative to weather and site conditions and > 100 are performing relative to weather and site conditions. b) The "PercentCover" subfolder contains every year's modeled cheatgrass percent cover estimates and their associated files, including a layer file. The cheatgrass percent cover format is ERDAS Imagine signed 8-bit....
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This raster represents a continuous surface of sage-grouse habitat suitability index (HSI) values for Nevada during summer, which is a surrogate for habitat conditions during the sage-grouse brood-rearing period.
A number of modeling approaches have been developed to predict the impacts of climate change on species distributions, performance and abundance. The stronger the agreement from models that represent different processes and are based on distinct and independent sources of information, the greater the confidence we can have in their predictions. Evaluating the level of confidence is particularly important when predictions are used to guide conservation or restoration decisions. We used a multi-model approach to predict climate change impacts on big sagebrush (Artemisia tridentata), the dominant plant species on roughly 43 million hectares in the western United States and a key resource for many endemic wildlife species....
Understanding how annual climate variation affects population growth rates across a species’ range may help us anticipate the effects of climate change on species distribution and abundance. We predict that populations in warmer or wetter parts of a species’ range should respond negatively to periods of above average temperature or precipitation, respectively, whereas populations in colder or drier areas should respond positively to periods of above average temperature or precipitation. To test this, we estimated the population sensitivity of a common shrub species, big sagebrush (Artemisia tridentata), to annual climate variation across its range. Our analysis includes 8175 observations of year-to-year change in...
There is widespread evidence that multiple drivers of global change, such as habitat degradation, invasive species, and climate change, are influencing wildlife. Understanding how these drivers interact with and affect species may be difficult because outcomes depend on the magnitude and duration of environmental change and the life history of the organism. In addition, various environmental drivers may be evaluated and managed at different spatial scales. We used a historical dataset from 1991 to 1994 and current information from 2010 to 2012 to examine whether occupancy patterns of wintering raptors were consistent with regional changes in distribution or habitat conditions within a local management unit, the...
Land managers are responsible for developing effective strategies for conserving and restoring Great Basin ecosystems in the face of invasive species, conifer expansion, and altered fire regimes. A warming climate is magnifying the effects of these threats and adding urgency to implementation of management practices that will maintain or improve ecosystem functioning. This Factsheet Series was developed to provide land managers with brief summaries of the best available information on contemporary management issues to facilitate science delivery and foster effective management. Each peer-reviewed factsheet was developed as a collaborative effort among knowledgeable scientists and managers. The series begins with...
Alpine and subalpine plant species are of special interest in ecology and ecophysiology because they represent life at the climate limit and changes in their relative abundances can be a bellwether for climate-change impacts. Perennial life forms dominate alpine plant communities, and their form and function reflect various avoidance, tolerance, or resistance strategies to interactions of cold temperature, radiation, wind, and desiccation stresses that prevail in the short growing seasons common (but not ubiquitous) in alpine areas. Plant microclimate is typically uncoupled from the harsh climate of the alpine, often leading to substantially warmer plant temperatures than air temperatures recorded by weather stations....


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