WorldWideScience

Sample records for region sierra nevada

  1. Aspen in the Sierra Nevada: Regional conservation of a continental species

    Science.gov (United States)

    Paul C. Rogers; Wayne D. Shepperd; Dale L. Bartos

    2007-01-01

    Quaking aspen (Populus tremuloides Michx.) a common species in North America, is a minor species in the Sierra Nevada of California. However, the limited coverage of aspen in this area appears to carry a disproportionate biodiversity load: numerous species are dependent on the unique components of aspen forests habitat. Land managers in the region...

  2. Survival of fishers in the southern Sierra Nevada region of California

    Science.gov (United States)

    Richard A. Sweitzer; Craig M. Thompson; Rebecca E. Green; Reginald H. Barrett; Kathryn L. Purcell

    2015-01-01

    Fishers in the western United States were recently proposed for listing under the U.S. Endangered Species Act because of concerns for loss of suitable habitat and evidence of a diversity of mortality risks that reduce survival. One of 2 remnant populations of fishers in California is in the southern Sierra Nevada region, where we studied them at 2 research sites in the...

  3. Sierra Nevada Subregional Boundary - Sierra Nevada Conservancy [ds542

    Data.gov (United States)

    California Natural Resource Agency — Sierra Nevada Conservancy (SNC) boundary. The boundary was mapped to correspond with statute AB 2600 (2004) and as re-defined in AB 1201 (2005). Work on the boundary...

  4. Biosphere and atmosphere interactions in Sierra Nevada forests

    Science.gov (United States)

    Allen H. Goldstein

    2004-01-01

    In the Sierra Nevada, studies are being conducted to assess the impacts of both anthropogenic and biogenic hydrocarbon emissions on regional tropospheric ozone and fine aerosol production. Impacts of ozone deposition and management practices on ecosystem health are also being studied. Human-induced changes in regional air quality have consequences for Sierra Nevada...

  5. Invasive exotic plant species in Sierra Nevada ecosystems

    Science.gov (United States)

    Carla M. D' Antonio; Eric L. Berlow; Karen L. Haubensak

    2004-01-01

    The Sierra Nevada is a topographically and floristically diverse region of the western United States. While it comprises only a fifth of the total land area of California, half of the native plant species in the state occur within the range. In addition, more than 400 plant species are endemic to the Sierra Nevada and many of these are listed as threatened or have...

  6. Status and understanding of groundwater quality in the Sierra Nevada Regional study unit, 2008: California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater quality in the Sierra Nevada Regional (SNR) study unit was investigated as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment Program Priority Basin Project. The study was designed to provide statistically unbiased assessments of the quality of untreated groundwater within the primary aquifer system of the Sierra Nevada. The primary aquifer system for the SNR study unit was delineated by the depth intervals over which wells in the State of California’s database of public drinking-water supply wells are open or screened. Two types of assessments were made: (1) a status assessment that described the current quality of the groundwater resource, and (2) an evaluation of relations between groundwater quality and potential explanatory factors that represent characteristics of the primary aquifer system. The assessments characterize untreated groundwater quality, rather than the quality of treated drinking water delivered to consumers by water distributors.

  7. Assessing the combined effect of dams and climate warming on streamflow in California's Sierra Nevada for regional-scale adaptation

    Science.gov (United States)

    Rheinheimer, D. E.; Viers, J. H.

    2012-12-01

    Dams and their operations harm river ecosystems, in part by altering the natural flow regimes that those ecosystems depend on. In the multi-reservoir water management systems of California's Sierra Nevada, greater emphasis is being placed on re-operating existing reservoir systems to recover downstream ecosystems. However, climate change is changing inflow patterns, affecting both ecosystems and traditional water system benefits across the region. As new reservoir operation schemes will be needed to manage for natural resources management objectives at the regional scale, characterizing historical and future environmental impacts of current operations across the region can aid in prioritizing planning efforts. We used a coarse-scale water resources simulation model developed for the western Sierra Nevada to explore the independent and combined effects of dams and climate warming on the flow regime directly below reservoirs, the focal point for instream flow requirements in operations licenses. We quantified changes to mean annual flow, annual low flow duration, annual runoff centroid timing, and weekly rate of decrease under binary combinations of management (unregulated/regulated) and climate (historical/future) conditions. We demonstrate that although rivers in the Sierra Nevada are currently managed in ways that are harmful to instream ecosystems, and that streamflow effects of operations are typically much worse than climate change effects, there are signals that reservoirs can potentially be used to help adapt to some of climate changes harmful effects with little additional effort in some cases. This study is the first step toward a better understanding of the environmental costs from and opportunities afforded by the current stock of reservoirs in a large hydroregion under changing social and environmental conditions.

  8. Groundwater quality in the Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2014-01-01

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project (PBP) of the GAMA Program provides a comprehensive assessment of the State’s groundwater quality and increases public access to groundwater-quality information. The Sierra Nevada Regional study unit constitutes one of the study units being evaluated.

  9. Quaternary environments in Sierra Nevada

    OpenAIRE

    Oliva, Marc; Gómez Ortiz, Antonio; Palacios Estremera, David; Salvador Franch, Ferran; Salvà Catarineu, Monserrat

    2016-01-01

    El conocimiento relativo a la evolución ambiental cuaternaria en las montañas de la Península Ibérica ha avanzado sustancialmente en las últimas décadas. Particularmente significativos son los progresos realizados en el macizo de Sierra Nevada, en el sur peninsular. En este caso, los investigadores se han servido de registros naturales y fuentes documentales para reconstruir la dinámica ambiental desde la Última Glaciación y posterior deglaciación del macizo hasta su evolución reciente. Los c...

  10. REGIONAL ANALYSIS OF INORGANIC NITROGEN YIELD AND RETENTION IN HIGH-ELEVATION ECOSYSTEMS OF THE SIERRA NEVADA AND ROCKY MOUNTAINS

    Science.gov (United States)

    Yields and retention of inorganic nitrogen (DIN) and nitrate concentrations in surface runoff are summarized for 28 high elevation watersheds in the Sierra Nevada, California and Rocky Mountains of Wyoming and Colorado. Catchments ranged in elevation from 2475 to 3603 m and from...

  11. Contaminant studies in the Sierra Nevadas

    Science.gov (United States)

    Sparling, D.W.; Fellers, G.

    2002-01-01

    full text: Several species of anuran amphibians (frogs and toads) are experiencing severe population declines in even seemingly pristine areas of the Sierra Mountains of California. Among the most severely depressed species are the redlegged frog, the foothill and mountain yellow-legged frogs, the Yosemite toad, and the Cascades frog. Several factors, such as habitat fragmentation, introduced predators (especially fish), and disease, have been linked to these declines. But recent evidence from a USGS-led study shows that contaminants are a primary factor. During the past three years, researchers from the USGS Patuxent Wildlife Research Center, the Western Ecology Research Center, the USDA Beltsville Agriculture Research Center, and the Texas A&M University have teamed up to conduct an extensive study on airborne pesticides and their effects on amphibian populations in the Sierra Nevada Mountains. Previous work on environmental chemistry demonstrated that pesticides from the intensely agricultural Central Valley of California are being blown into the more pristine Sierra Nevada Mountains, especially around Sequoia and Yosemite National Parks. Several pesticides, including diazinon, chlorpyrifos, malathion and endosulfan, can be measured in snow, rainfall, and pond waters in these national parks. With the exception of endosulfan, these pesticides affect and even kill both invertebrates and vertebrate species by inhibiting cholinesterase, an enzyme essential to proper nervous system functioning. In the summer of 2001, we published a paper showing that these same pesticides are now found in adults and the tadpoles of Pacific treefrogs. The results of this landmark study showed that more than 50 percent of the tadpoles and adults sampled in Yosemite and Sequoia National Parks had detectable levels of diazinon or chlorpyrifos and that 86 percent of the Pacific treefrogs sampled in the Lake Tahoe region had detectable levels of endosulfan. In contrast, frogs that were

  12. Micrometeorological Observations in a Sierra Nevada Meadow

    Science.gov (United States)

    Blackburn, D. A.; Oliphant, A. J.

    2016-12-01

    Mountain meadows play important roles on watershed and ecosystem services, including improving water quality, moderating runoff and providing biodiversity hotspots. In the Sierra Nevada, mountain meadows are an integral part of the mountain ecosystem and watersheds that impact more than 20 million people. Grazing, logging and other forms of anthropogenic land use in the Sierra Nevada have degraded the functioning of meadows, by altering the morphology, hydrology and vegetation. Existing meandering stream networks become incised and straightened by increased runoff, which effectively lowers the water table and completely alters the ecosystem from moist meadow sedges, grasses, and herbs to dryland grass and shrubs. Given the large growth cycle in healthy meadows, it is also expected that they sequester a significant amount of carbon and enhance atmospheric humidity through evapotranspiration, but relatively little work has been done on the bio-micrometeorology of meadows. The purpose of this study is to assess the growing season carbon, water and energy budgets of a partly degraded meadow in the northern Sierra Nevada. Loney Meadow, located at nearly 2,000 m in the Tahoe National Forest, has been identified as a degraded meadow and is scheduled to undergo restoration work to raise the water table in 2017. A micrometeorological tower with eddy covariance instruments was deployed at the site for most of the snow-free period from May to October 2016. The measurements include: fluxes of CO2, water vapor, surface radiation and energy budget components; ancillary meteorological and soil data; and an automated camera capturing daily images of the meadow surface. The poster will present diurnal and seasonal CO2 on a daily basis with a very rapid increase at the onset of the growing season.

  13. Environmental exposures to agrochemicals in the Sierra Nevada mountain range

    Science.gov (United States)

    LeNoir, J.; Aston, L.; Data, S.; Fellers, G.; McConnell, L.; Sieber, J.

    2000-01-01

    The release of pesticides into the environment may impact human and environmental health. Despite the need for environmental exposure data, few studies quantify exposures in urban areas and even fewer determine exposures to wildlife in remote areas. Although it is expected that concentrations in remote regions will be low, recent studies suggest that even low concentrations may have deleterious effects on wildlife. Many pesticides are known to interfere with the endocrine systems of humans and wildlife, adversely affecting growth, development, and behavior. This chapter reviews the fate and transport of pesticides applied in the Central Valley of California and quantifies their subsequent deposition into the relatively pristine Sierra Nevada Mountain Range.

  14. Geomagnetic Polarity Epochs: Sierra Nevada II.

    Science.gov (United States)

    Cox, A; Doell, R R; Dalrymple, G B

    1963-10-18

    Ten new determinations on volcanic extrusions in the Sierra Nevada with potassium-argon ages of 3.1 million years or less indicate that the remanent magnetizations fall into two groups, a normal group in which the remanent magnetization is directed downward and to the north, and a reversed group magnetized up and to the south. Thermomagnetic experiments and mineralogic studies fail to provide an explanation of the opposing polarities in terms of mineralogic control, but rather suggest that the remanent magnetization reflects reversals of the main dipole field of the earth. All available radiometric ages are consistent with this field-reversal hypothesis and indicate that the present normal polarity epoch (N1) as well as the previous reversed epoch (R1) are 0.9 to 1.0 million years long, whereas the previous normal epoch (N2) was at least 25 percent longer.

  15. Southern Sierra Nevada Continental Dynamics Project: 1993 field observations of the NPE

    Energy Technology Data Exchange (ETDEWEB)

    Keller, G.R. [Univ. of Texas, El Paso, TX (United States); Malin, P.E. [Duke Univ., Durham, NC (United States); Ruppert, S.D. [LLNL, Livermore, CA (United States)

    1994-12-31

    The Southern Sierra Nevada Continental Dynamics Project is a multidisciplinary, multi-institutional investigation of the cause of the uplift of the Sierra Nevada and its relationship to extension in the adjacent Basin and Range. A broad range of geologic and geophysical data have been collected as part of this project. These data include both passive and active seismic measurements, as well as gravity and magnetotelluric observations. Three seismic refraction/wide-angle reflection profiles were recorded: (1) a 325-km-long, north-south profile extending from just east of Mono Lake south across the Garlock fault, (2) a 400-km-long, east-west profile extending from Death Valley west across the Sierra Nevada to near the San Andreas fault, and (3) a 480-km-long, east-west profile deployed for the NPE. This profile extended from Beatty, Nevada, west across the Sierra Nevada along the previously recorded east-west profile and continued nearly to the Pacific Ocean. Up to 675 seismic recorders were deployed for each profile. These data are allowing us to develop refined models of the crustal and upper mantle structure of the southern Sierra Nevada and to evaluate alternative hypotheses for its uplift and for Basin and Range extension. They also provide insight into the propagation of regional phases across complex structures.

  16. Site fidelity of the declining amphibian Rana sierrae (Sierra Nevada yellow-legged frog)

    Science.gov (United States)

    Kathleen Matthews; Haiganoush Preisler

    2010-01-01

    From 1997 to 2006, we used mark–recapture models to estimate the site fidelity of 1250 Sierra Nevada yellow-legged frogs (Rana sierrae) in Kings Canyon National Park, California, USA, during their three main activity periods of overwintering, breeding, and feeding. To quantify site fidelity, the tendency to return to and reuse previously occupied...

  17. Using epiphytic macrolichen communities for biomonitoring ammonia in forests of the greater Sierra Nevada, California

    Science.gov (United States)

    Sarah Jovan; Bruce. Mccune

    2006-01-01

    Chronic, excessive nitrogen deposition is potentially an important ecological threat to forests of the greater Sierra Nevada in California. We developed a model for ammonia bioindication, a major nitrogen pollutant in the region, using epiphytic macrolichens. We used non-metric multidimensional scaling to extract gradients in lichen community composition from surveys...

  18. Developing and managing sustainable forest ecosystems for spotted owls in the Sierra Nevada

    Science.gov (United States)

    J. Verner; K.S. McKelvey

    1994-01-01

    Studies of the California spotted owl have revealed significant selection for habitats with large, old trees; relatively high basal areas of snags; and relatively high biomass in large, downed logs. Based on planning documents for national forests in the Sierra Nevada, we projected declining amounts of older-forest attributes. Region 5 has adopted measures to retain...

  19. Physiochemical characterization of insoluble residues in California Sierra Nevada snow

    Science.gov (United States)

    Creamean, Jessie; Axson, Jessica; Bondy, Amy; Craig, Rebecca; May, Nathaniel; Shen, Hongru; Weber, Michael; Warner, Katy; Pratt, Kerri; Ault, Andrew

    2015-04-01

    The effects atmospheric aerosols have on cloud particle formation are dependent on both the aerosol physical and chemical characteristics. For instance, larger, irregular-shaped mineral dusts efficiently form cloud ice crystals, enhancing precipitation, whereas small, spherical pollution aerosols have the potential to form small cloud droplets that delay the autoconversion of cloudwater to precipitation. Thus, it is important to understand the physiochemical properties and sources of aerosols that influence cloud and precipitation formation. We present an in-depth analysis of the size, chemistry, and sources of soluble and insoluble residues found in snow collected at three locations in the California Sierra Nevada Mountains during the 2012/2013 winter season. For all sites, February snow samples contained high concentrations of regional pollutants such as ammonium nitrate and biomass burning species, while March snow samples were influenced by mineral dust. The snow at the lower elevation sites in closer proximity to the Central Valley of California were heavily influenced by agricultural and industrial emissions, whereas the highest elevation site was exposed to a mixture of Central Valley pollutants in addition to long-range transported dust from Asia and Africa. Further, air masses likely containing transported dust typically traveled over cloud top heights at the low elevation sites, but were incorporated into the cold (-28°C, on average) cloud tops more often at the highest elevation site, particularly in March, which we hypothesize led to enhanced ice crystal formation and thus the observation of dust in the snow collected at the ground. Overall, understanding the spatial and temporal dependence of aerosol sources is important for remote mountainous regions such as the Sierra Nevada where snowpack provides a steady, vital supply of water.

  20. Nest trees of northern flying squirrels in the Sierra Nevada

    Science.gov (United States)

    Marc D. Meyer; Douglas A. Kelt; Malcolm P. North

    2005-01-01

    We examined the nest-tree preferences of northern flying squirrels (Glaucomys sabrinus) in an old-growth, mixed-conifer and red fir (Abies magnifica) forest of the southern Sierra Nevada of California. We tracked 27 individuals to 122 nest trees during 3 summers. Flying squirrels selected nest trees that were larger in diameter and...

  1. Groundwater quality in the Southern Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. The Tehachapi-Cummings Valley and Kern River Valley basins and surrounding watersheds in the Southern Sierra Nevada constitute one of the study units being evaluated.

  2. Groundwater quality in the Central Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater provides more than 40 percent of California's drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The Priority Basin Project of the GAMA Program provides a comprehensive assessment of the State's groundwater quality and increases public access to groundwater-quality information. Two small watersheds of the Fresno and San Joaquin Rivers in the Central Sierra Nevada constitute one of the study units being evaluated.

  3. Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.

    Directory of Open Access Journals (Sweden)

    Sarah E Null

    Full Text Available This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2 degrees, 4 degrees, and 6 degrees C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds.

  4. Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2014-01-01

    A detailed geographic record of recent vegetation regrowth and disturbance patterns in forests of the Sierra Nevada remains a gap that can be filled with remote sensing data. Landsat (TM) imagery was analyzed to detect 10 years of recent changes (between 2000 and 2009) in forest vegetation cover for areas burned by wildfires between years of 1995 to 1999 in the region. Results confirmed the prevalence of regrowing forest vegetation during the period 2000 and 2009 over 17% of the combined burned areas.

  5. Increasing elevation of fire in the Sierra Nevada and implications for forest change

    Science.gov (United States)

    Mark W. Schwartz; Nathalie Butt; Christopher R. Dolanc; Andrew Holguin; Max A. Moritz; Malcolm P. North; Hugh D. Safford; Nathan L. Stephenson; James H. Thorne; Phillip J. van Mantgem

    2015-01-01

    Fire in high-elevation forest ecosystems can have severe impacts on forest structure, function and biodiversity. Using a 105-year data set, we found increasing elevation extent of fires in the Sierra Nevada, and pose five hypotheses to explain this pattern. Beyond the recognized pattern of increasing fire frequency in the Sierra Nevada since the late 20th century, we...

  6. Nitrogen dynamics of spring-fed wetland ecosystems of the Sierra Nevada foothills oak woodland

    Science.gov (United States)

    Randall D. Jackson; Barbara Allen-Diaz

    2002-01-01

    Spring-fed wetlands are small, highly productive, patchy ecosystems nested within the oak woodland/annual grassland matrix of the Sierra Nevada foothills. In an effort to place these wetlands in a landscape context, we described seasonal variation (1999-2000 growing season) in nitrogen cycling parameters at 6 spring-fed wetland sites of the Sierra Nevada foothill oak...

  7. Correlations and Areal Distribution of the Table Mountain Formation, Stanislaus Group; Central Sierra Nevada, California

    Science.gov (United States)

    Torrez, G.; Carlson, C. W.; Putirka, K. D.; Pluhar, C. J.; Sharma, R. K.

    2011-12-01

    Late Cenozoic evolution of the western Cordillera is a matter of ongoing debate in geologic studies. Volcanic deposits within, and adjacent to the Sierra Nevada have played a significant role in many of these debates. With local faulting coincident with eruption of members of the Stanislaus Group at ca. 38°N, the composition and correlation of these volcanics can greatly aid our understanding of Sierra Nevada tectonics. At the crest of the central Sierra Nevada, 23 trachyandesite lava flows of the Table Mountain Formation, dated at ~10 Ma, cap Sonora Peak. These 23 flows compose the thickest and most complete known stratigraphic section of the Table Mountain Formation in the region. Located ~12 km east of Sonora Peak are 16 flows of trachyandesite at Grouse Meadow. We have collected a detailed set of geochemical and paleomagnetic data for flows of these two sections at Sonora Peak and Grouse Meadows in an attempt to correlate volcanic, paleomagnetic and structural events related to uplift and extension in the Sierra Nevada and the Walker Lane. Correlation of individual flows is possible based on: stratigraphic order, temporal gaps in deposition as determined by paleomagnetic remanence direction and nonconformities, and flow geochemistry. These correlations allow us to infer source localities, flow directions, and temporal changes in flow routes. The large number of flows present at Grouse Meadow provides an additional data set from which to correlate various localities in the region to those units not represented at Sonora Peak. Several flows which occur in the upper portions of the Sonora Peak and Grouse Meadow stratigraphic sections do not correlate between these localities. The causes of stratigraphic discontinuity potentially represent: tectonic isolation across the Sierran Crest, topographic isolation by the emplacement of younger flows, or the combination of the two. Additional to the correlation of individual flows at these localities, this study shows a

  8. Interaction of an Introduced Predator with Future Effects of Climate Change in the Recruitment Dynamics of the Imperiled Sierra Nevada Yellow-legged Frog (Rana sierrae)

    Science.gov (United States)

    I Lacan; Kathleen R. Matthews; K.V. Feldman

    2008-01-01

    Between-year variation in snowpack (from 20 to 200% of average) and summer rainfall cause large fluctuations in volume of small lakes in the higher elevation (> 3000 m) Sierra Nevada, which are important habitat for the imperiled Sierra Nevada Yellow-legged Frog, Rana sierrae. Climate change (global warming) is predicted to increase these...

  9. Resilience Through Disturbance: Effects of Wildfire on Vegetation and Water Balance in the Sierra Nevadas

    Science.gov (United States)

    Boisrame, G. F. S.; Thompson, S. E.; Stephens, S.; Collins, B.; Tague, N.

    2015-12-01

    A century of fire suppression in the Western United States has drastically altered the historically fire-adapated ecology in California's Sierra Nevada Mountains. Fire suppression is understood to have increased the forest cover, as well as the stem density, canopy cover and water demand of montane forests, reducing resilience of the forests to drought, and increasing the risk of catastrophic fire by drying the landscape and increasing fuel loads. The potential to reverse these trends by re-introducing fire into the Sierra Nevada is highly promising, but the likely effects on vegetation structure and water balance are poorly quantified. The Illilouette Creek Basin in Yosemite National Park represents a unique experiment in the Sierra Nevada, in which managers have moved from fire suppression to allowing a near-natural fire regime to prevail since 1972. Changes in vegetation structure in the Illilouette since the restoration of natural burning provides a unique opportunity to examine how frequent, mixed severity fires can reshape the Sierra Nevada landscape. We characterize these changes from 1969 to the present using a combination of Landsat products and high-resolution aerial imagery. We describe how the landscape structure has changed in terms of vegetation composition and its spatial organization, and explore the drivers of different post-fire vegetation type transitions (e.g. forest to shrubland vs. forest to meadow). By upscaling field data using vegetation maps and Landsat wetness indices, we explore how these vegetation transitions have impacted the water balance of the Illilouette Creek Basin, potentially increasing its resilience in the face of drought, climate change, and catastrophic fire. In a region that is adapted to frequent disturbance from fire, this work helps us understand how allowing such natural disturbances to take place can increase the sustainability of diverse landscapes in the long term.

  10. Using machine learning to predict snow water equivalent in the Sierra Nevada USA and Afghanistan

    Science.gov (United States)

    Bair, N.; Rittger, K.; Dozier, J.

    2017-12-01

    In many mountain regions, snowmelt provides most of the runoff. Ranges such as the Sierra Nevada USA benefit from hundreds of manual and automated snow measurement stations as well as basin-wide snow water equavalent (SWE) estimates from new platforms like the Airborne Snow Observatory. Thus, we have been able to use the Sierra Nevada as a testbed to validate an approach called SWE reconstruction, where the snowpack is built-up in reverse using downscaled energy balance forcings. Our past work has shown that SWE reconstruction produces some of the most accurate basin-wide SWE estimates, comparable in accuracy to a snow pillow/course interpolation, but requires no in situ measurements, which is its main advantage. The disadvantages are that reconstruction cannot be used for a forecast and is only valid during the ablation period. To address these shortcomings, we have used machine learning trained on reconstructed SWE in the Sierra Nevada and Afghanistan, where there are no accessible snowpack measurements. Predictors are physiographic and remotely-sensed variables, including brightness temperatures from a new enhanced resolution passive microwave dataset. Two machine learning techniques—bagged regression trees and feed-forward neural networks—were used. Results show little bias on average and training period, i.e. the ablation period.

  11. Vulnerability of birds to climate change in California's Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Rodney B. Siegel

    2014-06-01

    Full Text Available In a rapidly changing climate, effective bird conservation requires not only reliable information about the current vulnerability of species of conservation concern, but also credible projections of their future vulnerability. Such projections may enable managers to preempt or reduce emerging climate-related threats through appropriate habitat management. We used NatureServe's Climate Change Vulnerability Index (CCVI to predict vulnerability to climate change of 168 bird species that breed in the Sierra Nevada mountains of California, USA. The CCVI assesses species-specific exposure and sensitivity to climate change within a defined geographic area, through the integration of (a species' range maps, (b information about species' natural history traits and ecological relationships, (c historic and current climate data, and (d spatially explicit climate change projections. We conducted the assessment under two different downscaled climate models with divergent projections about future precipitation through the middle of the 21st century. Assessments differed relatively little under the two climate models. Of five CCVI vulnerability ranking categories, only one species, White-tailed Ptarmigan (Lagopus leucura, received the most vulnerable rank, Extremely Vulnerable. No species received the second-highest vulnerability ranking, Highly Vulnerable. Sixteen species scored as Moderately Vulnerable using one or both climate models: Common Merganser (Mergus merganser, Osprey (Pandion haliaetus, Bald Eagle (Haliaeetus leucocephalus, Northern Goshawk (Accipiter gentilis, Peregrine Falcon (Falco peregrinus, Prairie Falcon (Falco mexicanus, Spotted Sandpiper (Actitis macularius, Great Gray Owl (Strix nebulosa, Black Swift (Cypseloides niger, Clark's Nutcracker (Nucifraga columbiana, American Dipper (Cinclus mexicanus, Swainson's Thrush (Catharus ustulatus, American Pipit (Anthus rubescens, Gray-crowned Rosy-Finch (Leucosticte tephrocotis, Pine Grosbeak

  12. GPS Imaging of vertical land motion in California and Nevada: Implications for Sierra Nevada uplift

    Science.gov (United States)

    Blewitt, Geoffrey; Kreemer, Corné

    2016-01-01

    Abstract We introduce Global Positioning System (GPS) Imaging, a new technique for robust estimation of the vertical velocity field of the Earth's surface, and apply it to the Sierra Nevada Mountain range in the western United States. Starting with vertical position time series from Global Positioning System (GPS) stations, we first estimate vertical velocities using the MIDAS robust trend estimator, which is insensitive to undocumented steps, outliers, seasonality, and heteroscedasticity. Using the Delaunay triangulation of station locations, we then apply a weighted median spatial filter to remove velocity outliers and enhance signals common to multiple stations. Finally, we interpolate the data using weighted median estimation on a grid. The resulting velocity field is temporally and spatially robust and edges in the field remain sharp. Results from data spanning 5–20 years show that the Sierra Nevada is the most rapid and extensive uplift feature in the western United States, rising up to 2 mm/yr along most of the range. The uplift is juxtaposed against domains of subsidence attributable to groundwater withdrawal in California's Central Valley. The uplift boundary is consistently stationary, although uplift is faster over the 2011–2016 period of drought. Uplift patterns are consistent with groundwater extraction and concomitant elastic bedrock uplift, plus slower background tectonic uplift. A discontinuity in the velocity field across the southeastern edge of the Sierra Nevada reveals a contrast in lithospheric strength, suggesting a relationship between late Cenozoic uplift of the southern Sierra Nevada and evolution of the southern Walker Lane. PMID:27917328

  13. A Method for Snow Reanalysis: The Sierra Nevada (USA) Example

    Science.gov (United States)

    Girotto, Manuela; Margulis, Steven; Cortes, Gonzalo; Durand, Michael

    2017-01-01

    This work presents a state-of-the art methodology for constructing snow water equivalent (SWE) reanalysis. The method is comprised of two main components: (1) a coupled land surface model and snow depletion curve model, which is used to generate an ensemble of predictions of SWE and snow cover area for a given set of (uncertain) inputs, and (2) a reanalysis step, which updates estimation variables to be consistent with the satellite observed depletion of the fractional snow cover time series. This method was applied over the Sierra Nevada (USA) based on the assimilation of remotely sensed fractional snow covered area data from the Landsat 5-8 record (1985-2016). The verified dataset (based on a comparison with over 9000 station years of in situ data) exhibited mean and root-mean-square errors less than 3 and 13 cm, respectively, and correlation greater than 0.95 compared with in situ SWE observations. The method (fully Bayesian), resolution (daily, 90-meter), temporal extent (31 years), and accuracy provide a unique dataset for investigating snow processes. This presentation illustrates how the reanalysis dataset was used to provide a basic accounting of the stored snowpack water in the Sierra Nevada over the last 31 years and ultimately improve real-time streamflow predictions.

  14. Paleozoic and Mesozoic deformations in the central Sierra Nevada, California

    Science.gov (United States)

    Nokleberg, Warren J.; Kistler, Ronald Wayne

    1980-01-01

    Analysis of structural and stratigraphic data indicates that several periods of regional deformation, consisting of combined folding, faulting, cataclasis, and regional metamorphism, occurred throughout the central Sierra Nevada during Paleozoic and Mesozoic time. The oldest regional deformation occurred alono northward trends during the Devonian and Mississippian periods in most roof pendants containing lower Paleozoic metasedimentary rocks at the center and along the crest of the range. This deformation is expressed in some roof pendants by an angular unconformity separating older thrice-deformed from younger twice-deformed Paleozoic metasedimentary rocks. The first Mesozoic deformation, which consisted of uplift and erosion and was accompanied by the onset of Andean-type volcanism during the Permian and Triassic, is expressed by an angular unconformity in several roof pendants from the Saddlebag Lake to the Mount Morrison areas. This unconformity is defined by Permian and Triassic andesitic to rhyolitic metavolcanic rocks unconformably overlying more intensely deformed Pennsylvanian, Permian(?), and older metasedimentary rocks. A later regional deformation occurred during the Triassic along N. 20?_30? W. trends in Permian and Triassic metavolcanic rocks of the Saddlebag Lake and Mount Dana roof pendants, in upper Paleozoic rocks of the Pine Creek roof pendant, and in the Calaveras Formation of the western metamorphic belt; the roof pendants are crosscut by Upper Triassic granitic rocks of the Lee Vining intrusive epoch. A still later period of Early and Middle Jurassic regional deformation occurred along N. 30?-60? E. trends in upper Paleozoic rocks of the Calaveras Formation of the western metamorphic belt. A further period of deformation was the Late Jurassic Nevadan orogeny, which occurred along N. 20?_40? W. trends in Upper Jurassic rocks of the western metamorphic belt that are crosscut by Upper Jurassic granitic rocks of the Yosemite intrusive epoch

  15. Ozone distribution in remote ecologically vulnerable terrain of the southern Sierra Nevada, CA

    International Nuclear Information System (INIS)

    Panek, Jeanne; Saah, David; Esperanza, Annie; Bytnerowicz, Andrzej; Fraczek, Witold; Cisneros, Ricardo

    2013-01-01

    Ozone concentration spatial patterns remain largely uncharacterized across the extensive wilderness areas of the Sierra Nevada, CA, despite being downwind of major pollution sources. These natural areas, including four national parks and four national forests, contain forest species that are susceptible to ozone injury. Forests stressed by ozone are also more vulnerable to other agents of mortality, including insects, pathogens, climate change, and ultimately fire. Here we analyze three years of passive ozone monitor data from the southern Sierra Nevada and interpolate landscape-scale spatial and temporal patterns during the summer-through-fall high ozone concentration period. Segmentation analysis revealed three types of ozone exposure sub-regions: high, low, and variable. Consistently high ozone exposure regions are expected to be most vulnerable to forest mortality. One high exposure sub-region has been documented elsewhere as being further vulnerable to increased drought and fire potential. Identifying such hot-spots of forest vulnerability has utility for prioritizing management. -- Highlights: •Three years of passive ozone sampler data over 49,000 km 2 were analyzed spatially. •Spatial and temporal ozone patterns were mapped across the Sierra Nevada, CA. •Sub-regions of consistently high, low and variable ozone exposure were identified. •The 1700–2400 m elevation band delineated a distinct break in ozone concentration. •This approach has utility for prioritizing management across vulnerable landscapes. -- A passive ozone sampler network in combination with spatial analysis techniques was used to characterize landscape-scale ozone patterns and dynamics, identifying regions of consistently high and low ozone exposure for forest management prioritization

  16. Spatiotemporal patterns of fault slip rates across the Central Sierra Nevada frontal fault zone

    Science.gov (United States)

    Rood, Dylan H.; Burbank, Douglas W.; Finkel, Robert C.

    2011-01-01

    Patterns in fault slip rates through time and space are examined across the transition from the Sierra Nevada to the Eastern California Shear Zone-Walker Lane belt. At each of four sites along the eastern Sierra Nevada frontal fault zone between 38 and 39° N latitude, geomorphic markers, such as glacial moraines and outwash terraces, are displaced by a suite of range-front normal faults. Using geomorphic mapping, surveying, and 10Be surface exposure dating, mean fault slip rates are defined, and by utilizing markers of different ages (generally, ~ 20 ka and ~ 150 ka), rates through time and interactions among multiple faults are examined over 10 4-10 5 year timescales. At each site for which data are available for the last ~ 150 ky, mean slip rates across the Sierra Nevada frontal fault zone have probably not varied by more than a factor of two over time spans equal to half of the total time interval (~ 20 ky and ~ 150 ky timescales): 0.3 ± 0.1 mm year - 1 (mode and 95% CI) at both Buckeye Creek in the Bridgeport basin and Sonora Junction; and 0.4 + 0.3/-0.1 mm year - 1 along the West Fork of the Carson River at Woodfords. Data permit rates that are relatively constant over the time scales examined. In contrast, slip rates are highly variable in space over the last ~ 20 ky. Slip rates decrease by a factor of 3-5 northward over a distance of ~ 20 km between the northern Mono Basin (1.3 + 0.6/-0.3 mm year - 1 at Lundy Canyon site) to the Bridgeport Basin (0.3 ± 0.1 mm year - 1 ). The 3-fold decrease in the slip rate on the Sierra Nevada frontal fault zone northward from Mono Basin is indicative of a change in the character of faulting north of the Mina Deflection as extension is transferred eastward onto normal faults between the Sierra Nevada and Walker Lane belt. A compilation of regional deformation rates reveals that the spatial pattern of extension rates changes along strike of the Eastern California Shear Zone-Walker Lane belt. South of the Mina Deflection

  17. Holocene glaciation of the central Sierra Nevada, California

    Science.gov (United States)

    Bowerman, Nicole D.; Clark, Douglas H.

    2011-05-01

    Sediment cores from two bedrock-dammed lakes in North Fork Big Pine Creek, Sierra Nevada, California, preserve the most detailed and complete record of Holocene glaciation yet recovered in the region. The lakes are fed by outwash from the Palisade Glacier, the largest (˜1.3 km 2) and presumably longest-lived glacier in the range, and capture essentially all of the rock flour it produces. Distinct late-Holocene (Matthes) and late-Pleistocene (Recess Peak) moraines lie between the modern glacier and the lakes. The lakes have therefore received continuous sedimentation from the basin since the retreat of the Tioga glacier (Last Glacial Maximum) and capture rock flour related to all post-LGM advances. A total of eight long cores (up to 5.5 m sediment depth) and one short surface sediment short core preserve a coherent record of fluctuating rock flour flux to the lakes through the Holocene. Age constraints on rock flour spikes in First and Second lakes based on 31 14C-dated macrofossils indicate Holocene glaciation began ˜3200 cal yr B P, followed by a possible glacier maximum at ˜2800 cal yr B P and four distinct glacier maxima at ˜2200, ˜1600, ˜700 and ˜250-170 cal yr. B.P., the most recent maximum being the largest. Reconstruction of the equilibrium-line altitudes (ELA) associated with each distinct advance recorded in the moraines (Recess Peak, Matthes, and modern) indicates ELA depressions (relative to modern) of ˜250 m and 90 m for Recess Peak and Matthes advances, respectively. These differences represent decreases in summer temperatures of 1.7-2.8 °C (Recess Peak) and 0.2-2° (Matthes), and increases in winter precipitation of 22-34 cm snow water equivalent (s.w.e.) (Recess Peak) and 3-26 cm s.w.e. (Matthes) compared to modern conditions. Although small, these changes are significant and similar to those noted in the Cascade Range to the north, and represent a significant departure from historical climate trends in the region.

  18. Rock-Ice Feature Inventory for the Sierra Nevada, California, USA, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Sierra Nevada is a tectonic uplift mountain range with a gradual gain in elevation on the west side and a steep escarpment on the east. Most of the mapped...

  19. Potential environmental effects of pack stock on meadow ecosystems of the Sierra Nevada, USA

    Science.gov (United States)

    Ostoja, Steven M.; Brooks, Matthew L.; Moore, Peggy E.; Berlow, Eric L.; Robert Blank,; Roche, Jim; Chase, Jennifer T.; Sylvia Haultain,

    2014-01-01

    Pack and saddle stock, including, but not limited to domesticated horses, mules, and burros, are used to support commercial, private and administrative activities in the Sierra Nevada. The use of pack stock has become a contentious and litigious issue for land management agencies in the region inter alia due to concerns over effects on the environment. The potential environmental effects of pack stock on Sierra Nevada meadow ecosystems are reviewed and it is concluded that the use of pack stock has the potential to influence the following: (1) water nutrient dynamics, sedimentation, temperature, and microbial pathogen content; (2) soil chemistry, nutrient cycling, soil compaction and hydrology; (3) plant individuals, populations and community dynamics, non-native invasive species, and encroachment of woody species; and (4) wildlife individuals, populations and communities. It is considered from currently available information that management objectives of pack stock should include the following: minimise bare ground, maximise plant cover, maintain species composition of native plants, minimise trampling, especially on wet soils and stream banks, and minimise direct urination and defecation by pack stock into water. However, incomplete documentation of patterns of pack stock use and limited past research limits current understanding of the effects of pack stock, especially their effects on water, soils and wildlife. To improve management of pack stock in this region, research is needed on linking measurable monitoring variables (e.g. plant cover) with environmental relevancy (e.g. soil erosion processes, wildlife habitat use), and identifying specific environmental thresholds of degradation along gradients of pack stock use in Sierra Nevada meadows.

  20. Uranium-lead isotopic ages from the Sierra Nevada Batholith, California

    Science.gov (United States)

    Chen, J.

    1982-01-01

    This study provides new information on the timing and distribution of Mesozoic magmatic events in the Sierra Nevada batholithic complex chiefly between 36° and 37°N. latitude. U-Pb ages have been determined for 133 zircon and 7 sphene separates from 82 samples of granitoid rocks. Granitoid rocks in this area range in age from 217 to 80 m.y. Triassic intrusions are restricted to the east side of the batholith; Jurassic plutons occur south of the Triassic plutons east of the Sierra Nevada, as isolated masses within the Cretaceous batholith, and in the western foothills of the range; Cretaceous plutons form a continuous belt along the axis of the batholith and occur as isolated masses east of the Sierra Nevada. No granitic intrusions were emplaced for 37 m.y. east of the Sierra Nevada following the end of Jurassic plutonism. However, following emplacement of the eastern Jurassic granitoids, regional extension produced a fracture system at least 350 km long into which the dominantly mafic, calc-alkalic Independence dike swarm was intruded 148 m.y. ago. The dike fractures probably represents a period of regional crustal extension caused by a redistribution of the regional stress pattern accompanying the Nevadan orogeny. Intrusion of Cretaceous granitic plutons began in large volume about 120 m.y. ago in the western Sierra Nevada and migrated steadily eastward for 40 m.y. at a rate of 2.7 mm/y. This slow and constant migration indicates remarkably uniform conditions of subduction with perhaps downward migration of parent magma generation or a slight flattening of the subduction zone. Such steady conditions could be necessary for the production of large batholithic complexes such as the Sierra Nevada. The abrupt termination of plutonism 80 m.y. ago may have resulted from an increased rate of convergence of the American and eastern Pacific plates and dramatic flattening of the subduction zone. U-Pb ages of the Giant Forest-alaskite sequence in Sequoia National Park are

  1. Los recursos humanos en un espacio natural protegido: Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Ma. Enriqueta Cózar

    2000-01-01

    Full Text Available Sierra Nevada, como todas las áreas de montaña españolas y gran parte del territorio interior andaluz, ha experimentado durante el siglo XX un considerable retroceso demográfico. La población con la que llega al umbral del siglo XXI es una cuarta parte más pequeña que la registrada en 1900 y un tercio inferior a la de 1950. Diversos y complejos factores, tanto internos como externos al área de montaña, de carácter más económico que demográfico, fueron los desencadenantes de una fuerte emigración. La gran pérdida de población ha originado cambios trascendentales en la demografía y en la actividad económica de Sierra Nevada. En la actualidad, la población de este espacio protegido se caracteriza por una desequilibrada distribución en el territorio, un escaso crecimiento natural, un acelerado envejecimiento y una actividad mayoritariamente terciaria. La declaración, en Julio de 1989, como espacio natural protegido bajo la figura de Parque Natural, y la más reciente de Parque Nacional, apenas ha modificado la inercia demográfica regresiva de la mayor parte de sus municipios; tan sólo se ha podido apreciar una cierta tendencia a la estabilización demográfica de la población total del macizo

  2. High-Elevation Sierra Nevada Conifers Reveal Increasing Reliance on Snow Water with Changing Climate

    Science.gov (United States)

    Lepley, K. S.; Meko, D. M.; Touchan, R.; Shamir, E.; Graham, R.

    2017-12-01

    Snowpack in the Sierra Nevada Mountains accounts for around one third of California's water supply. Melting snow can provide water into dry summer months characteristic of the region's Mediterranean climate. As climate changes, understanding patterns of snowpack, snowmelt, and biological response are critical in this region of agricultural, recreational, and ecological value. Tree rings can act as proxy records to inform scientists and resource managers of past climate variability where instrumental data is unavailable. Here we investigate relationships between tree rings of high-elevation, snow-adapted conifer trees (Tsuga mertensiana, Abies magnifica) and April 1st snow-water equivalent (SWE) in the northern Sierra Nevada Mountains. The 1st principal component of 29 highly correlated regional SWE time series was modeled using multiple linear regression of four tree-ring chronologies including two lagged chronologies. Split-period verification analysis of this model revealed poor predictive skill in the early half (1929 - 1966) of the calibration period (1929 - 2003). Further analysis revealed a significant (p time. Snow water is becoming a more limiting resource to tree growth as average temperatures rise and the hydrologic regime shifts. These results highlight the need for resource managers and policy makers to consider that biological response to climate is not static.

  3. Evaluating the Spatial Distribution of Toxic Air Contaminants in Multiple Ecosystem Indicators in the Sierra Nevada-Southern Cascades

    Science.gov (United States)

    Nanus, L.; Simonich, S. L.; Rocchio, J.; Flanagan, C.

    2013-12-01

    Toxic air contaminants originating from agricultural areas of the Central Valley in California threaten vulnerable sensitive receptors including surface water, vegetation, snow, sediments, fish, and amphibians in the Sierra Nevada-Southern Cascades region. The spatial distribution of toxic air contaminants in different ecosystem indicators depends on variation in atmospheric concentrations and deposition, and variation in air toxics accumulation in ecosystems. The spatial distribution of organic air toxics and mercury at over 330 unique sampling locations and sample types over two decades (1990-2009) in the Sierra Nevada-Southern Cascades region were compiled and maps were developed to further understand spatial patterns and linkages between air toxics deposition and ecological effects. Potential ecosystem impacts in the Sierra Nevada-Southern Cascades region include bioaccumulation of air toxics in both aquatic and terrestrial ecosystems, reproductive disruption, and immune suppression. The most sensitive ecological end points in the region that are affected by bioaccumulation of toxic air contaminants are fish. Mercury was detected in all fish and approximately 6% exceeded human consumption thresholds. Organic air toxics were also detected in fish yielding variable spatial patterns. For amphibians, which are sensitive to pesticide exposure and potential immune suppression, increasing trends in current and historic use pesticides are observed from north to south across the region. In other indicators, such as vegetation, pesticide concentrations in lichen increase with increasing elevation. Current and historic use pesticides and mercury were also observed in snowpack at high elevations in the study area. This study shows spatial patterns in toxic air contaminants, evaluates associated risks to sensitive receptors, and identifies data gaps. Future research on atmospheric modeling and information on sources is needed in order to predict which ecosystems are the

  4. Topographic Evolution of the Sierra Nevada Resolved by Inversion of Low-Temperature Thermochronology

    Science.gov (United States)

    McPhillips, D. F.; Brandon, M. T.

    2011-12-01

    At present, there are two competing ideas for the topographic evolution of the Sierra Nevada Range. One idea is that the Sierra Nevada was formed as a monocline in the Cretaceous, marking the transition from the Great Valley forearc basin to the west, and a high Nevadaplano plateau to the east, similar to the west flank of the modern Altiplano of the Andes. Both the thermochronologic signature of local relief and the stable isotopic evidence of a topographic rain shadow support this hypothesis. However, a suite of geomorphic observations suggests that the Sierra gained a large fraction of its present elevation as recently as the Pliocene. This recent surface uplift could have been driven by convective removal of in the lower part of the lithosphere and/or by changes in dynamic topography associated with deep subduction of the Farallon plate. Here we present the first comprehensive analysis of low-temperature thermochronology in the Sierra Nevada, which provides a definitive solution, which indicates that both ideas are likely correct. Our analysis is distinguished by three new factors: The first is that we allow for separate evolutions for the local relief and the long-wavelength topography. Second, we use Al-in-Hb paleobarometry to constrain the initial depth of emplacement for the Sierra Nevada plutons. Third, our analysis is tied to a sea-level reference by using the paleo-bathymetric record of the Great Valley basin, where it on-laps the Sierra Nevada batholith. According to our analysis, westward tilting of the Sierra accounts for 2 km of uplift since 20 Ma. Topographic relief increased by a factor of 2. These findings suggest that the Sierra Nevada lost elevation through most of the Tertiary but regained much of its initial elevation following the onset of surface uplift in the Miocene.

  5. Monitoring lichens diversity and climatic change in Sierra Nevada (Spain

    Directory of Open Access Journals (Sweden)

    Fernández Calzado, M.ª R.

    2013-12-01

    Full Text Available Lichens are common organisms in high mountain zones, where they play an important role in ecosystem balance. In recent years, the increasing interest in understanding more about their interactions with abiotic factors has prompted several investigations, some of which have proved their value as bioindicators of climatic conditions. In this context, focusing on climatic change effects on high mountain vascular plants and supported by the Global Observation Research Initiative in Alpine Environments project (GLORIA, we have monitored for the first time the lichens biodiversity in Sierra Nevada with the intention of studying the alterations caused by the process of climatic change. The aim of this paper is to explain the monitoring experience developed on the massif and contribute to the first results from the biodiversity and statistical analysis of the sampling data.Los líquenes son organismos comunes en las zonas de alta montaña donde juegan un importante papel en el equilibrio de los ecosistemas. En los últimos años, el creciente interés por entender más acerca de sus interacciones con los factores abióticos ha motivado diversas investigaciones, algunas de las cuales han demostrado su valor como bioindicadores de las condiciones climáticas. En este contexto, centrándonos en los efectos del cambio climático en plantas vasculares de alta montaña y respaldados por el proyecto “Iniciativa para la investigación y el seguimiento global de los ambientes alpinos (GLORIA”, se ha monitorizado por primera vez la diversidad de líquenes en Sierra Nevada con la intención de estudiar las posibles alteraciones que esta pueda sufrir causadas por el proceso de cambio climático. El objetivo de este artículo es el de dar a conocer la experiencia de seguimiento en el macizo y aportar los primeros resultados procedentes del análisis, tanto de la biodiversidad como estadístico, de los datos de muestreo.

  6. Fumio Matsumura--accomplishments at the University of California, Davis, and in the Sierra Nevada Mountains.

    Science.gov (United States)

    Seiber, James N

    2015-05-01

    Fumio Matsumura joined the University of California, Davis, faculty in 1987 where he served as founding director of the Center for Environmental Health Sciences, associate director of the U.C. Toxic Substances Research and Teaching Program, and chair of the Department of Environmental Toxicology. He was an active affiliate with the NIEHS-funded Superfund Basic Research Program and the NIH Comprehensive Cancer Center. He was in many instances a primary driver or otherwise involved in most activities related to environmental toxicology at Davis, including the education of students in environmental biochemistry and ecotoxicology. A significant part of his broad research program was focused on the long range transport of chemicals such as toxaphene, PCBs and related contaminants used or released in California to the Sierra Nevada mountains, downwind of the urban and agricultural regions of the state. He hypothesized that these chemical residues adversely affected fish and wildlife, and particularly the declining populations of amphibians in Sierra Nevada streams and lakes. Fumio and his students and colleagues found residues of toxaphene and PCBs at higher elevations, an apparent result of atmospheric drift and deposition in the mountains. Fumio and his wife Teruko had personal interests in, and a love of the mountains, as avid skiers, hikers, and outdoor enthusiasts. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Assessing the spatial variability of mountain precipitation in California's Sierra Nevada using the Airborne Snow Observatory

    Science.gov (United States)

    Brandt, T.; Deems, J. S.; Painter, T. H.; Dozier, J.

    2016-12-01

    In California's Sierra Nevada, 10 or fewer winter storms are responsible for most of the annual precipitation, which falls mostly as snow. Presently, surface stations are used to measure the dynamics of mountain precipitation. However, even in places like the Sierra Nevada—one of the most gauged regions in the world—the paucity of surface stations can lead to large errors in precipitation thereby biasing both total water year and short-term streamflow forecasts. Remotely sensed snow depth and water equivalent, at a time scale that resolves storms, might provide a novel solution to the problems of: (1) quantifying the spatial variability of mountain precipitation; and (2) assessing gridded precipitation products that are mostly based on surface station interpolation. NASA's Airborne Snow Observatory (ASO), an imaging spectrometer and LiDAR system, has measured snow in the Tuolumne River Basin in California's Sierra Nevada for the past four years, 2013-2016; and, measurements will continue. Principally, ASO monitors the progression of melt for water supply forecasting, nonetheless, a number of flights bracketed storms allowing for estimates of snow accumulation. In this study we examine a few of the ASO recorded storms to determine both the basin and subbasin orographic effect as well as the spatial patterns in total precipitation. We then compare these results to a number of gridded climate products and weather models including: Daymet, the Parameter-elevation Regressions on Independent Slopes Model (PRISM), the North American Land Data Assimilation System (NLDAS-2), and the Weather Research and Forecasting (WRF) model. Finally, to put each ASO recorded storm into context, we use a climatology produced from snow pillows and the North American Regional Reanalysis (NARR) for 2014-2016 to examine key accumulation events, and classify storms based on their integrated water vapor flux.

  8. The saltiest springs in the Sierra Nevada, California

    Science.gov (United States)

    Moore, James G.; Diggles, Michael F.; Evans, William C.; Klemic, Karin

    2017-07-20

    The five saltiest springs in the Sierra Nevada in California are found between 38.5° and 38.8° N. latitude, on the South Fork American River; on Caples Creek, a tributary of the Silver Fork American River; and on the North Fork Mokelumne River. The springs issue from Cretaceous granitic rocks in the bottoms of these major canyons, between 1,200- and 2,200-m elevation. All of these springs were well known to Native Americans, who excavated meter-sized basins in the granitic rock, within which they produced salt by evaporation near at least four of the five spring sites. The spring waters are dominated by Cl, Na, and Ca; are enriched relative to seawater in Ca, Li, and As; and are depleted in SO4, Mg, and K. Tritium analyses indicate that the spring waters have had little interaction with rainfall since about 1954. The waters are apparently an old groundwater of meteoric origin that resided at depth before moving up along fractures to the surface of the exhumed granitic rocks. However, along the way these waters incorporated salts from depth, the origin of which could have been either from marine sedimentary rocks intruded by the granitic magmas or from fluid inclusions in the granitic rocks. Prolonged storage at depth fostered water-rock interactions that undoubtedly modified the fluid compositions.

  9. Dataset of Passerine bird communities in a Mediterranean high mountain (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Barea-Azcón, José Miguel; Álvarez-Ruiz, Lola; Bonet-García, Francisco Javier; Zamora, Regino

    2016-01-01

    Abstract In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:26865820

  10. Dataset of Passerine bird communities in a Mediterranean high mountain (Sierra Nevada, Spain).

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Barea-Azcón, José Miguel; Álvarez-Ruiz, Lola; Bonet-García, Francisco Javier; Zamora, Regino

    2016-01-01

    In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  11. Airborne LiDAR analysis and geochronology of faulted glacial moraines in the Tahoe-Sierra frontal fault zone reveal substantial seismic hazards in the Lake Tahoe region, California-Nevada USA

    Science.gov (United States)

    Howle, James F.; Bawden, Gerald W.; Schweickert, Richard A.; Finkel, Robert C.; Hunter, Lewis E.; Rose, Ronn S.; von Twistern, Brent

    2012-01-01

    We integrated high-resolution bare-earth airborne light detection and ranging (LiDAR) imagery with field observations and modern geochronology to characterize the Tahoe-Sierra frontal fault zone, which forms the neotectonic boundary between the Sierra Nevada and the Basin and Range Province west of Lake Tahoe. The LiDAR imagery clearly delineates active normal faults that have displaced late Pleistocene glacial moraines and Holocene alluvium along 30 km of linear, right-stepping range front of the Tahoe-Sierra frontal fault zone. Herein, we illustrate and describe the tectonic geomorphology of faulted lateral moraines. We have developed new, three-dimensional modeling techniques that utilize the high-resolution LiDAR data to determine tectonic displacements of moraine crests and alluvium. The statistically robust displacement models combined with new ages of the displaced Tioga (20.8 ± 1.4 ka) and Tahoe (69.2 ± 4.8 ka; 73.2 ± 8.7 ka) moraines are used to estimate the minimum vertical separation rate at 17 sites along the Tahoe-Sierra frontal fault zone. Near the northern end of the study area, the minimum vertical separation rate is 1.5 ± 0.4 mm/yr, which represents a two- to threefold increase in estimates of seismic moment for the Lake Tahoe basin. From this study, we conclude that potential earthquake moment magnitudes (Mw) range from 6.3 ± 0.25 to 6.9 ± 0.25. A close spatial association of landslides and active faults suggests that landslides have been seismically triggered. Our study underscores that the Tahoe-Sierra frontal fault zone poses substantial seismic and landslide hazards.

  12. Soil fauna in forest and coffee plantations from the Sierra Nevada de Santa Mar ta, Colombia

    International Nuclear Information System (INIS)

    Camero R, Edgar

    2002-01-01

    Two research stations (M inca, 700 m altitude and Maria Ter esa, 790 m altitude) were established in the Sierra Nevada de Santa Mar ta in places to study the soil fauna associated with forest and coffee plantations. Soil fauna was collected using pitfall and Bailer's traps. Samples were taken from litter as well as from horizons 0, A and B. individuals collected were identified to family level. Diversity, abundance and frequency indexes were used to compare fauna composition at both sites. Significant differences were found between the two research sites as well as with data from other high altitude forest in the Sierra Nevada de Santa Mar ta

  13. Plan for a Sierra Nevada Hydrologic Observatory: Science Aims, Measurement Priorities, Research Opportunities and Expected Impacts

    Science.gov (United States)

    Bales, R.; Dozier, J.; Famiglietti, J.; Fogg, G.; Hopmans, J.; Kirchner, J.; Meixner, T.; Molotch, N.; Redmond, K.; Rice, R.; Sickman, J.; Warwick, J.

    2004-12-01

    In response to NSF's plans to establish a network of hydrologic observatories, a planning group is proposing a Sierra Nevada Hydrologic Observatory (SNHO). As argued in multiple consensus planning documents, the semi-arid mountain West is perhaps the highest priority for new hydrologic understanding. Based on input from over 100 individuals, it is proposed to initiate a mountain-range-scale study of the snow-dominated hydrology of the region, focusing on representative 1,000-5,000 km2 river basins originating in the Sierra Nevada and tributary to the Sacramento-San-Joaquin Delta. The SNHO objective is to provide the necessary infrastructure for improved understanding of surface-water and ground-water systems, their interactions and their linkages with ecosystems, biogeochemistry, agriculture, urban areas and water resources in semi-arid regions. The SNHO will include east-west transects of hydrological observations across the Sierra Nevada and into the basin and range system, in four distinct latitude bands that span much of the variability found in the semi-arid West. At least one transect will include agricultural and urban landscapes of the Great Central Valley. Investments in measurement systems will address scales from the mountain range down to the basin, headwater catchment and study plot. The intent is to provide representative measurements that will yield general knowledge as opposed to site-specific problem solving of a unique system. The broader, general science question posed by the planning group is: How do mountain hydrologic processes vary across landscapes, spanning a range of latitudes, elevations and thus climate, soils, geology and vegetation zones?\\" Embodied are additional broad questions for the hydrologic science community as a whole: (i) How do hydrologic systems that are subjected to multiple perturbations respond? (ii) How do pulses and changes propagate through the hydrologic system? (iii) What are the time lags and delays of stresses in

  14. Surface motion of active rock glaciers in the Sierra Nevada, California, USA: inventory and a case study using InSAR

    Science.gov (United States)

    L. Liu; C.I. Millar; R.D. Westfall; H.A. Zebker

    2013-01-01

    Despite the abundance of rock glaciers in the Sierra Nevada of California, USA, few efforts have been made to measure their surface flow. Here we use the interferometric synthetic aperture radar (InSAR) technique to compile a~benchmark inventory describing the kinematic state of 59 active rock glaciers in this region. Statistically, these rock glaciers moved at...

  15. Inevitable changes in snowpack and water resources over California's Sierra Nevada

    Science.gov (United States)

    Hall, A. D.; Sun, F.; Walton, D.; Berg, N.; Schwartz, M. A.

    2015-12-01

    Here we use a downscaling technique incorporating both dynamical and statistical methods to project end-of-century changes in spring snow water equivalent in California's Sierra Nevada. The technique produces outcomes for all Global Climate Models (GCMs) and the four greenhouse gas forcing scenarios adopted by the Intergovernmental Panel on Climate Change (IPCC). For all GCMs and forcing scenarios, significant snow loss occurs at elevations below 2500 meters, despite increasing precipitation in many GCMs. The loss is significantly enhanced by snow albedo feedback. The approximate intermodel range in percent of total snow remaining in the entire region is 60-85% for a likely "mitigation" scenario, and 35-55% for the "business-as-usual" scenario. Thus significant snowpack decrease by century's end is inevitable, even if the loss can be cushioned through greenhouse gas emissions reductions over the coming decades. The snowpack loss also leads to significant changes in runoff timing, which are also inevitable.

  16. Soil moisture datasets at five sites in the central Sierra Nevada and northern Coast Ranges, California

    Science.gov (United States)

    Stern, Michelle A.; Anderson, Frank A.; Flint, Lorraine E.; Flint, Alan L.

    2018-05-03

    In situ soil moisture datasets are important inputs used to calibrate and validate watershed, regional, or statewide modeled and satellite-based soil moisture estimates. The soil moisture dataset presented in this report includes hourly time series of the following: soil temperature, volumetric water content, water potential, and total soil water content. Data were collected by the U.S. Geological Survey at five locations in California: three sites in the central Sierra Nevada and two sites in the northern Coast Ranges. This report provides a description of each of the study areas, procedures and equipment used, processing steps, and time series data from each site in the form of comma-separated values (.csv) tables.

  17. Mineralogy and geochemistry of two metamorphosed sedimentary manganese deposits, Sierra Nevada, California, USA

    Science.gov (United States)

    Flohr, M.J.K.; Huebner, J.S.

    1992-01-01

    composition and some textures of the sedimentary protoliths at both Sierra Nevada deposits. Jacobsite-rich layers probably represent a Fe-rich protolith. Caryopilite and manganoan calcite represent additional protoliths at the Manga-Chrome mine. The metamorphic assemblage prehnite-chlorite-epidote-calcite in a metabasalt from the Smith prospect constrains regional metamorphic conditions to a maximum temperature of 325??C and a pressure of 2 kbar. Slightly higher temperatures are indicated by the presence of actinolite in another metabasalt. Compositions of Mn-rich minerals in Smith samples are consistent with these metamorphic conditions. ?? 1992.

  18. Influence of anuran prey on the condition and distribution of Rana muscosa in the Sierra Nevada

    Science.gov (United States)

    K.L. Pope; K.R. Matthews

    2002-01-01

    Mountain yellow-legged frogs (Rana muscosa) at high elevations of the Sierra Nevada must obtain enough food during summer to survive 7–9 winter months when their aquatic habitats are frozen and food is presumably unavailable. Adults of R. muscosa prey on a variety of organisms, including aquatic and terrestrial invertebrates and...

  19. Fire weather and large fire potential in the northern Sierra Nevada

    Science.gov (United States)

    Brandon M. Collins

    2014-01-01

    Fuels, weather, and topography all contribute to observed fire behavior. Of these, weather is not only the most dynamic factor, it is the most likely to be directly influenced by climate change. In this study 40 years of daily fire weather observations from five weather stations across the northern Sierra Nevada were analyzed to investigate potential changes or trends...

  20. Role of oaks in fisher habitat quality in the Sierra Nevada mountains at multiple spatial scales

    Science.gov (United States)

    Craig M. Thompson; Kathryn Purcell; Rebecca Green; Richard. Sweitzer

    2015-01-01

    Fishers (Pekania pennanti) occur in ponderosa pine, mixed conifer, and mixed hardwood conifer habitats in the southern Sierra Nevada at elevations from approximately 1400 to 2300 m. They are a candidate species for listing under both the Federal and California Endangered Species Acts. Since 2007, the U.S. Department of Agriculture, Forest Service (...

  1. Ethnobotany of the Sierra Nevada del Cocuy-Güicán

    NARCIS (Netherlands)

    Rodríguez, Mireia Alcántara; Angueyra, Andrea; Cleef, Antoine M.; Andel, van Tinde

    2018-01-01

    Background: The Sierra Nevada del Cocuy-Güicán in the Colombian Andes is protected as a National Natural Park since 1977 because of its fragile páramo ecosystems, extraordinary biodiversity, high plant endemism, and function as water reservoir. The vegetation on this mountain is threatened by

  2. Snowmelt runoff and water yield along elevation and temperature gradients in California's southern Sierra Nevada

    Science.gov (United States)

    Carolyn T. Hunsaker; Thomas W. Whitaker; Roger C. Bales

    2012-01-01

    Differences in hydrologic response across the rain-snow transition in the southern Sierra Nevada were studied in eight headwater catchments – the Kings River Experimental Watersheds – using continuous precipitation, snowpack, and streamflow measurements. The annual runoff ratio (discharge divided by precipitation) increased about 0.1 per 300 m of mean catchment...

  3. Evaluating avian-habitat relationships models in mixed-conifer forests of the Sierra Nevada

    Science.gov (United States)

    Kathryn L. Purcell; Sallie J. Hejl; Terry A. Larson

    1992-01-01

    Using data from two studies in the southern and central Sierra Nevada, we compared the presence and abundance of bird species breeding in mixedconifer forests during 1978-79 and 1983-85 to predictions &om the California Wildlife Habitat Relationships (WHR) System. Twelve percent of the species observed in either study were not predicted by the WHR database to occur...

  4. Silviculture-ecology of forest-zone hardwoods in the Sierra Nevada

    Science.gov (United States)

    Philip M. McDonald; John C. Tappeiner

    1996-01-01

    Although the principal hardwood species in the forest zone of the Sierra Nevada (California black oak, tanoak, Pacific madrone, and canyon live oak) are key components of many ecosystems, they have received comparatively little study. Currently they are underutilized and unmanaged. This paper brings together what is known on the silviculture-ecology of these species...

  5. Carbon and nutrient contents in soils from the Kings River Experimental Watersheds, Sierra Nevada Mountains, California

    Science.gov (United States)

    D.W. Johnson; C.T. Hunsaker; D.W. Glass; B.M. Rau; B.A. Roath

    2011-01-01

    Soil C and nutrient contents were estimated for eight watersheds in two sites (one high elevation, Bull, and one low elevation, Providence) in the Kings River Experimental Watersheds in the western Sierra Nevada Mountains of California. Eighty-seven quantitative pits were dug to measure soil bulk density and total rock content, while three replicate surface samples...

  6. Sierra Nevada grasslands: interactions between livestock grazing and ecosystem structure and function

    Science.gov (United States)

    Barbara H. Allen-Diaz

    2004-01-01

    Livestock grazing plays an integral role in the grass-dominated ecosystems of the Sierra Nevada. Grazing has been asserted to influence such key ecological characteristics as water quality, net primary productivity, nutrient cycling, plant and animal diversity, wildlife habitat availability, and oak regeneration (Belsky and others 1999, Kauffmann and Krueger 1984)....

  7. PARTITIONING OF WATER FLUX IN A SIERRA NEVADA PONDEROSA PINE PLANTATION. (R826601)

    Science.gov (United States)

    The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus pond...

  8. West nile virus anti-body surveillance in three Sierra Nevada raptors of conservation concern

    Science.gov (United States)

    J.M. Hull; J.J. Keane; L.A. Tell; H.B. Ernest

    2010-01-01

    West Nile virus (WNV) infection has caused high levels of mortality in North American hawks and owls. To investigate the extent of infection among raptors of conservation concern in the Sierra Nevada, we tested 62 Northern Goshawks (Accipiter gentilis), 209 Spotted Owls (Strix occidentalis), and 22 Great Gray Owls (...

  9. Burn Severity and Its Impact on Soil Properties: 2016 Erskine Fire in the Southern Sierra Nevada

    Science.gov (United States)

    Haake, S.; Guo, J.; Krugh, W. C.

    2017-12-01

    Wildfire frequency in the southern Sierra Nevada has increased over the past decades. The effects of wildfires on soils can increase the frequency of slope failure and debris flow events, which pose a greater risk to people, as human populations expand into foothill and mountainous communities of the Sierra Nevada. Alterations in the physical properties of burned soils are one such effect that can catalyze slope failure and debris flow events. Moreover, the degree of a soil's physical alteration resulting from wildfire is linked to fire intensity. The 2016 Erskine fire occurred in the southern Sierra Nevada, burning 48,019 acres, resulting in soils of unburned, low, moderate, and high burn severities. In this study, the physical properties of soils with varying degrees of burn severity are explored within the 2016 Erskine fire perimeter. The results constrain the effects of burn severity on soil's physical properties. Unburned, low, moderate, and high burn severity soil samples were collected within the Erskine fire perimeter. Alterations in soils' physical properties resulting from burn severity are explored using X-ray diffractometry analysis, liquid limit, plastic limit, and shear strength tests. Preliminary results from this study will be used to assess debris flow and slope failure hazard models within burned areas of the Kern River watershed in the southern Sierra Nevada.

  10. From Typology to Topography in Clarence King's "Mountaineering in the Sierra Nevada."

    Science.gov (United States)

    Hoekzema, Loren

    The book "Mountaineering in the Sierra Nevada" by Clarence King, a late-ninteenth-century American geologist, writer, art critic, and romantic, is discussed in this paper. In the writing and revision of this book, King was attempting a metamorphosis of landscape description into popular reading as he moved from being a symbolic writer to…

  11. Partitioning of water flux in a Sierra Nevada ponderosa pine plantation

    Science.gov (United States)

    Kurpius, M.R.; Panek, J.A.; Nikolov, N.T.; McKay, M.; Goldstein, Allen H.

    2003-01-01

    The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus ponderosa) in this region. To investigate how year-round water fluxes were partitioned in a young ponderosa pine ecosystem in the Sierra Nevada Mountains, water fluxes were continually measured from June 2000 to May 2001 using a combination of sap flow and eddy covariance techniques (above- and below-canopy). Water fluxes were modeled at our study site using a biophysical model, FORFLUX. During summer and fall water fluxes were equally partitioned between transpiration and soil evaporation while transpiration dominated the water fluxes in winter and spring. The trees had high rates of canopy conductance and transpiration in the early morning and mid-late afternoon and a mid-day depression during the dry season. We used a diurnal centroid analysis to show that the timing of high canopy conductance and transpiration relative to high vapor pressure deficit (D) shifted with soil moisture: during periods of low soil moisture canopy conductance and transpiration peaked early in the day when D was low. Conversely, during periods of high soil moisture canopy conductance and transpiration peaked at the same time or later in the day than D. Our observations suggest a general strategy by the pine trees in which they maximize stomatal conductance, and therefore carbon fixation, throughout the day on warm sunny days with high soil moisture (i.e. warm periods in winter and late spring) and maximize stomatal conductance and carbon fixation in the morning through the dry periods. FORFLUX model estimates of evaporation and transpiration were close to measured/calculated values during the dry period, including the drought, but underestimated transpiration and overestimated evaporation during the wet period. ?? 2003

  12. Modeling Multi-Reservoir Hydropower Systems in the Sierra Nevada with Environmental Requirements and Climate Warming

    Science.gov (United States)

    Rheinheimer, David Emmanuel

    Hydropower systems and other river regulation often harm instream ecosystems, partly by altering the natural flow and temperature regimes that ecosystems have historically depended on. These effects are compounded at regional scales. As hydropower and ecosystems are increasingly valued globally due to growing values for clean energy and native species as well as and new threats from climate warming, it is important to understand how climate warming might affect these systems, to identify tradeoffs between different water uses for different climate conditions, and to identify promising water management solutions. This research uses traditional simulation and optimization to explore these issues in California's upper west slope Sierra Nevada mountains. The Sierra Nevada provides most of the water for California's vast water supply system, supporting high-elevation hydropower generation, ecosystems, recreation, and some local municipal and agricultural water supply along the way. However, regional climate warming is expected to reduce snowmelt and shift runoff to earlier in the year, affecting all water uses. This dissertation begins by reviewing important literature related to the broader motivations of this study, including river regulation, freshwater conservation, and climate change. It then describes three substantial studies. First, a weekly time step water resources management model spanning the Feather River watershed in the north to the Kern River watershed in the south is developed. The model, which uses the Water Evaluation And Planning System (WEAP), includes reservoirs, run-of-river hydropower, variable head hydropower, water supply demand, and instream flow requirements. The model is applied with a runoff dataset that considers regional air temperature increases of 0, 2, 4 and 6 °C to represent historical, near-term, mid-term and far-term (end-of-century) warming. Most major hydropower turbine flows are simulated well. Reservoir storage is also

  13. Anthropogenic Warming Impacts on Today's Sierra Nevada Snowpack and Flood Severity

    Science.gov (United States)

    Huang, X.; Hall, A. D.; Berg, N.

    2017-12-01

    Focusing on this recent extreme wet year over California, this study investigates the warming impacts on the snowpack and the flood severity over the Sierra Nevada (SN), where the majority of the precipitation occurs during the winter season and early spring. One of our goals is to quantify anthropogenic warming impacts on the snow water equivalent (SWE) including recent historical warming and prescribed future projected warming scenarios; This work also explores to what extent flooding risk has increased under those warming cases. With a good representation of the historical precipitation and snowpack over the Sierra Nevada from the historical reference run at 9km (using WRF), the results from the offline Noah-MP simulations with perturbed near-surface temperatures reveal magnificent impacts of warming to the loss of the average snowpack. The reduction of the SWE under warming mainly results from the decreased rain-to-snow conversion with a weaker effect from increased snowmelt. Compared to the natural case, the past industrial warming decreased the maximum SWE by about one-fifth averaged over the study area. Future continuing warming can result in around one-third reduction of current maximum SWE under RCP4.5 emissions scenario, and the loss can reach to two-thirds under RCP8.5 as a "business-as-usual" condition. The impact of past warming is particularly outstanding over the North SN region where precipitation dominates and over the middle elevation regions where the snow mainly distributes. In the future, the warming impact on SWE progresses to higher regions, and so to the south and east. Under the business-as-usual scenario, the projected mid-elevation snowpack almost disappears by April 1st with even high-elevation snow reduced by about half. Along with the loss of the snowpack, as the temperature warms, floods can also intensify with increased early season runoff especially under heavy-rainy days caused by the weakened rain-to-snow processes and

  14. Population dynamics of spotted owls in the Sierra Nevada, California

    Science.gov (United States)

    Blakesley, J.A.; Seamans, M.E.; Conner, M.M.; Franklin, A.B.; White, Gary C.; Gutierrez, R.J.; Hines, J.E.; Nichols, J.D.; Munton, T.E.; Shaw, D.W.H.; Keane, J.J.; Steger, G.N.; McDonald, T.L.

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia and Kings Canyon National Parks (SKC). These study areas represented a broad spectrum of habitat and management conditions in these mountain ranges. We estimated apparent survival probability, reproductive output, and rate of population change for spotted owls on individual study areas and for all study areas combined (meta-analysis) using model selection or model-averaging based on maximum-likelihood estimation. We followed a formal protocol to conduct this analysis that was similar to other spotted owl meta-analyses. Consistency of field and analytical methods among our studies reduced confounding methodological effects when evaluating results. We used 991 marked spotted owls in the analysis of apparent survival. Apparent survival probability was higher for adult than for subadult owls. There was little difference in apparent survival between male and female owls. Model-averaged mean estimates of apparent survival probability of adult owls varied from 0.811 ?? 0.021 for females at LAS to 0.890 ?? 0.016 for males at SKC. Apparent survival increased over time for owls of all age classes at LAS and SIE, for adults at ELD, and for second-year subadults and adults at SKC. The meta-analysis of apparent survival, which included only adult owls, confirmed an increasing trend in survival over time. Survival rates were higher for owls on SKC than on the other study areas. We analyzed data

  15. Airborne Pesticides as an Unlikely Cause for Population Declines of Alpine Frogs in the Sierra Nevada, California

    Science.gov (United States)

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured...

  16. Thymus × pseudogranatensis (Labiatae, nuevo híbrido para Sierra Nevada (España

    Directory of Open Access Journals (Sweden)

    Lorite, Juan

    2011-12-01

    Full Text Available Thymus × pseudogranatensis Vizoso, F.B. Navarro & Lorite, a new spontaneous hybrid of Th. granatensis Boiss. subsp. granatensis and Th. zygis L. subsp. gracilis (Boiss. R. Morales, collected in the dolomitic areas of Sierra Nevada (SE Spain, is described. Morphological characters of the new nothospecies are analysed and its distribution and ecology are discussed.Se describe Thymus × pseudogranatensis Vizoso, F.B. Navarro & Lorite, un nuevo híbrido entre Th. granatensis Boiss. subsp. granatensis y Th. zygis L. subsp. gracilis (Boiss. R. Morales, colectado en la orla dolomítica de Sierra Nevada (SE de España. Se analizan los caracteres morfológicos de la nueva notoespecie y se aportan detalles sobre su hábitat y distribución.

  17. Observations of the diurnal and seasonal trends in nitrogen oxides in the western Sierra Nevada

    Directory of Open Access Journals (Sweden)

    J. G. Murphy

    2006-01-01

    Full Text Available Observations of speciated nitrogen oxides, namely NO2, total peroxy nitrates (ΣPNs, total alkyl nitrates (ΣANs, and HNO3 by thermal dissociation laser induced fluorescence (TD-LIF, and supporting chemical and meteorological measurements at Big Hill (1860 m, a high elevation site in California's Sierra Nevada Mountains, are described. From May through October, terrain-driven winds in the region routinely bring air from Sacramento, 100 km southwest of the site, upslope over oak and pine forests to Big Hill during the day, while at night, the site often samples clean, dry air characteristic of the free troposphere. Winter differs mainly in that the meteorology does not favour the buildup of Sacramento's pollution over the Sierra Nevada range, and the urban-influenced air that is seen has been less affected by biogenic VOC emissions, resulting in longer lifetime for NO2 and a predominance of the inorganic forms of nitrogen oxides. Summertime observations at Big Hill can be compared with those from Granite Bay, a Sacramento suburb, and from the University of California's Blodgett Forest Research Station to examine the evolution of nitrogen oxides and ozone within the urban plume. Nitrogen oxide radicals (NO and NO2, which dominate total nitrogen oxides (NOy at Granite Bay, are rapidly converted into HNO3, ΣPNs, and ΣANs, such that these compounds contribute 29, 30, and 21% respectively to the NOy budget in the plume at Big Hill. Nevertheless, the decreasing concentrations of NO2 as the plume is advected to Big Hill lead to decreases in the production rate of HNO3 and ozone. The data also demonstrate the role that temperature plays in sequestering NO2 into peroxy nitrates, effectively decreasing the rate of ozone production. The important contribution of ΣANs to NOy in the region suggests that they should be considered with regards to export of NOy from the boundary layer. Nocturnal observations of airmasses characteristic of the

  18. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

    OpenAIRE

    Antonio Jesús Pérez-Luque; Cristina Patricia Sánchez-Rojas; Regino Zamora; Ramón Pérez-Pérez; Francisco Javier Bonet

    2015-01-01

    Abstract Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems...

  19. Groundwater quality in the Mokelumne, Cosumnes, and American River Watersheds, Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Shelton, Jennifer L.

    2018-03-23

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Program’s Priority Basin Project assesses the quality of groundwater resources used for drinking water supply and increases public access to groundwater-quality information. In the Mokelumne, Cosumnes, and American River Watersheds of the Sierra Nevada, many rural households rely on private wells for their drinking-water supplies.

  20. Magma mixing in granitic rocks of the central Sierra Nevada, California

    Science.gov (United States)

    Reid, John B.; Evans, Owen C.; Fates, Dailey G.

    1983-12-01

    The El Capitan alaskite exposed in the North American Wall, Yosemite National Park, was intruded by two sets of mafic dikes that interacted thermally and chemically with the host alaskite. Comparisons of petrographic and compositional data for these dikes and alaskite with published data for Sierra Nevada plutons lead us to suggest that mafic magmas were important in the generation of the Sierra Nevada batholith. Specifically, we conclude that: (1) intrusion of mafic magmas in the lower crust caused partial melting and generation of alaskite (rhyolitic) magmas; (2) interaction between the mafic and felsic magmas lead to the observed linear variation diagrams for major elements; (3) most mafic inclusions in Sierra Nevada plutons represent chilled pillows of mafic magmas, related by fractional crystallization and granitoid assimilation, that dissolve into their felsic host and contaminate it to intermediate (granodioritic) compositions; (4) vesiculation of hydrous mafic magma upon chilling may allow buoyant mafic inclusions and their disaggregation products to collect beneath a pluton's domed ceiling causing the zoning (mafic margins-to-felsic core) that these plutons exhibit.

  1. Cretaceous plutonic rocks in the Donner Lake-Cisco Grove area, northern Sierra Nevada, California

    Science.gov (United States)

    Kulow, Matthew J.; Hanson, Richard E.; Girty, Gary H.; Girty, Melissa S.; Harwood, David S.

    1998-01-01

    The northernmost occurrences of extensive, glaciated exposures of the Sierra Nevada batholith occur in the Donner Lake-Cisco Grove area of the northern Sierra Nevada. The plutonic rocks in this area, which are termed here the Castle Valley plutonic assemblage, crop out over an area of 225 km2 and for the most part are shown as a single undifferentiated mass on previously published geological maps. In the present work, the plutonic assemblage is divided into eight separate intrusive units or lithodemes, two of which each consist of two separate plutons. Compositions are dominantly granodiorite and tonalite, but diorite and granite form small plutons in places. Spectacular examples of comb layering and orbicular texture occur in the diorites. U-Pb zircon ages have been obtained for all but one of the main units and range from ~120 to 114 Ma, indicating that the entire assemblage was emplaced in a narrow time frame in the Early Cretaceous. This is consistent with abundant field evidence that many of the individual phases were intruded penecontemporaneously. The timing of emplacement correlates with onset of major Cretaceous plutonism in the main part of the Sierra Nevada batholith farther south. The emplacement ages also are similar to isotopic ages for gold-quartz mineralization in the Sierran foothills west of the study area, suggesting a direct genetic relationship between the voluminous Early Cretaceous plutonism and hydrothermal gold mineralization.

  2. Wireless sensor networks to assess the impacts of global change in Sierra Nevada (Spain) mountains

    Science.gov (United States)

    Sánchez-Cano, Francisco M.; Bonet-García, Francisco J.; Pérez-Luque, Antonio J.; Suárez-Muñoz, María

    2017-04-01

    Sierra Nevada Global Change Observatory (southern Spain) aims to improve the ability of ecosystems to address the impacts of global change. To this end, a monitoring program has been implemented based on the collection of long time series on a multitude of biophysical variables. This initiative is part of the Long Term Ecological Research network and is connected to similar ones at national and international level. One of the specific objectives of this LTER site is to improve understanding of the relationships between abiotic factors and ecosystem functioning / structure. Wireless sensor networks are a key instrument for achieving this aim. This contribution describes the design and management of a sensor network that is intended to monitor several biophysical variables with high temporal and spatial resolution in Quercus pyrenaica forests located in this mountain region. The following solution has been adopted in order to obtain the observational data (physical and biological variables). The biological variables will be monitored by PAR sensors (photosynthetically active radiation), and the physical variables will be acquired by a meteorological station and a sensor network composed of temperature and soil moisture sensors, as well as air temperature and humidity ones. To complete the monitoring of the biological variables, a NDVI (Normalized Difference Vegetation Index) camera will be deployed focusing to a Quercus pyrenaica forest from the opposite slope. It should be noted that all monitoring systems exposed will be powered by solar energy. The management of the sensor network covers the deployment of more than 100 sensors, guaranteeing both remote accessibility and reliability of the data. The chosen solution is provided by the company Adevice whose ONE-GO communication system ensures a consistent and efficient sending of those values read by the different sensors towards a central point, from where the information (RAW data) is accessible through WiFi/3G

  3. Subpixel Snow-covered Area Including Differentiated Grain Size from AVIRIS Data Over the Sierra Nevada Mountain Range

    Science.gov (United States)

    Hill, R.; Calvin, W. M.; Harpold, A. A.

    2016-12-01

    Mountain snow storage is the dominant source of water for humans and ecosystems in western North America. Consequently, the spatial distribution of snow-covered area is fundamental to both hydrological, ecological, and climate models. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were collected along the entire Sierra Nevada mountain range extending from north of Lake Tahoe to south of Mt. Whitney during the 2015 and 2016 snow-covered season. The AVIRIS dataset used in this experiment consists of 224 contiguous spectral channels with wavelengths ranging 400-2500 nanometers at a 15-meter spatial pixel size. Data from the Sierras were acquired on four days: 2/24/15 during a very low snow year, 3/24/16 near maximum snow accumulation, and 5/12/16 and 5/18/16 during snow ablation and snow loss. Previous retrieval of subpixel snow-covered area in alpine regions used multiple snow endmembers due to the sensitivity of snow spectral reflectance to grain size. We will present a model that analyzes multiple endmembers of varying snow grain size, vegetation, rock, and soil in segmented regions along the Sierra Nevada to determine snow-cover spatial extent, snow sub-pixel fraction and approximate grain size or melt state. The root mean squared error will provide a spectrum-wide assessment of the mixture model's goodness-of-fit. Analysis will compare snow-covered area and snow-cover depletion in the 2016 year, and annual variation from the 2015 year. Field data were also acquired on three days concurrent with the 2016 flights in the Sagehen Experimental Forest and will support ground validation of the airborne data set.

  4. Approach to seismic hazard analysis for dam safety in the Sierra Nevada and Modoc Plateau of California

    International Nuclear Information System (INIS)

    Savage, W.U.; McLaren, M.K.; Edwards, W.D.; Page, W.D.

    1991-01-01

    Pacific Gas and Electric Company's hydroelectric generating system involves about 150 dams located in the Sierra Nevada and Modoc Plateau region of central and northern California. The utility's strategy for earthquake hazard assessment is described. The approach includes the following strategies: integrating regional tectonics, seismic geology, historical seismicity, microseismicity, and crustal structure to form a comprehensive regional understanding of the neotectonic setting; performing local studies to acquire data as needed to reduce uncertainties in geologic and seismic parameters of fault characteristics near specific dam sites; applying and extending recently developed geologic, seismologic, and earthquake engineering technologies to the current regional and site-specific information to evaluate fault characteristics, to estimate maximum earthquakes, and to characterize ground motion; and encouraging multiple independent reviews of earthquake hazard studies by conducting peer reviews, making field sites available to regulating agencies, and publishing results, methods and data in open literature. 46 refs., 8 tabs

  5. Can footwall unloading explain late Cenozoic uplift of the Sierra Nevada crest?

    Science.gov (United States)

    Thompson, G.A.; Parsons, T.

    2009-01-01

    Globally, normal-fault displacement bends and warps rift flanks upwards, as adjoining basins drop downwards. Perhaps the most evident manifestations are the flanks of the East African Rift, which cuts across the otherwise minimally deformed continent. Flank uplift was explained by Vening Meinesz (1950, Institut Royal Colonial Belge, Bulletin des Seances, v. 21, p. 539-552), who recognized that isostasy should cause uplift of a normal-faulted footwall and subsidence of its hanging wall. Uplift occurs because slip on a dipping normal fault creates a broader root of less-dense material beneath the footwall, and a narrowed one beneath the hanging wall. In this paper, we investigate the potential influence of this process on the latest stages of Sierra Nevada uplift. Through theoretical calculations and 3D finite element modelling, we find that cumulative slip of about 4km on range-front faults would have produced about 1.3km peak isostatic uplift at the ridge crest. Numerical models suggest that the zone of uplift is narrow, with the width controlled by bending resistance of the seismogenic crust. We conclude that footwall unloading cannot account for the entire elevation of the Sierran crest above sea level, but if range-front faulting initiated in an already elevated plateau like the adjacent Basin and Range Province, then a hybrid model of pre-existing regional uplift and localized footwall unloading can account for the older and newer uplift phases suggested by the geologic record.

  6. Potential increase in floods in California's Sierra Nevada under future climate projections

    Science.gov (United States)

    Das, T.; Dettinger, M.D.; Cayan, D.R.; Hidalgo, H.G.

    2011-01-01

    California's mountainous topography, exposure to occasional heavily moisture-laden storm systems, and varied communities and infrastructures in low lying areas make it highly vulnerable to floods. An important question facing the state-in terms of protecting the public and formulating water management responses to climate change-is "how might future climate changes affect flood characteristics in California?" To help address this, we simulate floods on the western slopes of the Sierra Nevada Mountains, the state's primary catchment, based on downscaled daily precipitation and temperature projections from three General Circulation Models (GCMs). These climate projections are fed into the Variable Infiltration Capacity (VIC) hydrologic model, and the VIC-simulated streamflows and hydrologic conditions, from historical and from projected climate change runs, allow us to evaluate possible changes in annual maximum 3-day flood magnitudes and frequencies of floods. By the end of the 21st Century, all projections yield larger-than-historical floods, for both the Northern Sierra Nevada (NSN) and for the Southern Sierra Nevada (SSN). The increases in flood magnitude are statistically significant (at p models, while under the third scenario, GFDL CM2. 1, frequencies remain constant or decline slightly, owing to an overall drying trend. These increases appear to derive jointly from increases in heavy precipitation amount, storm frequencies, and days with more precipitation falling as rain and less as snow. Increases in antecedent winter soil moisture also play a role in some areas. Thus, a complex, as-yet unpredictable interplay of several different climatic influences threatens to cause increased flood hazards in California's complex western Sierra landscapes. ?? 2011 Springer Science+Business Media B.V.

  7. Geochronology and Geochemistry of a Late Cretaceous Granitoid Suite, Santa Rosa Range, Nevada: Linking Arc Magmatism in Northwestern Nevada to the Sierra Nevada Batholith

    Science.gov (United States)

    Brown, K.; Stuck, R.; Hart, W. K.

    2010-12-01

    Throughout the Mesozoic, an arc-trench system dominated the western margin of North America. One of the principal records of this system’s evolution is a discontinuous alignment of deeply eroded batholiths, which represent the once-active roots of ancient volcanic systems. Although these batholiths extend from Alaska to Mexico, there is a prominent (~500 km) gap located in present-day Nevada that contains scattered plutons that are hypothesized to be similar in age and origin to the larger batholiths. The current understanding of these isolated plutons, however, remains limited to regional isotopic studies aimed at identifying major crustal boundaries and structural studies focused on emplacement mechanisms. Therefore, detailed petrogenetic studies of the plutons exposed within the Santa Rosa Range (SRR) of NW Nevada will better characterize magmatism in this region, placing them within a regional context that explores the hypothesized links between the intrusions of NW Nevada to the Sierra Nevada batholith (SNB). A compilation of published geochronology from this region shows that plutons in the SRR are broadly coeval with the Cathedral Range Intrusive Epoch (~95-83 Ma) and the Shaver Sequence (~118-105 Ma) of the SNB. Preliminary Rb-Sr geochronology from the Granite Peak stock reveals a previously unrecognized period of magmatism (ca. 85.0 Ma) in this region. Therefore, ongoing work will more completely characterize the timing of magmatic pulses in this region and their relationships to the SNB. Preliminary petrographic, geochemical, and isotopic observations suggest that two distinct compositional/textural groups exist: the Santa Rosa/ Andorno group (SRA) and Granite Peak/ Sawtooth group (GPS). The chemical and isotopic variations between the two groups suggest that they were not consanguineous. Whereas the SRA group is generally more mafic (64-72 wt% SiO2) and metaluminous, the GPS group is more felsic (72- 76 wt% SiO2) and peraluminous. This observation is

  8. Simulating 3-D radiative transfer effects over the Sierra Nevada Mountains using WRF

    Directory of Open Access Journals (Sweden)

    Y. Gu

    2012-10-01

    Full Text Available A surface solar radiation parameterization based on deviations between 3-D and conventional plane-parallel radiative transfer models has been incorporated into the Weather Research and Forecasting (WRF model to understand the solar insolation over mountain/snow areas and to investigate the impact of the spatial and temporal distribution and variation of surface solar fluxes on land-surface processes. Using the Sierra-Nevada in the western United States as a testbed, we show that mountain effect could produce up to −50 to + 50 W m−2 deviations in the surface solar fluxes over the mountain areas, resulting in a temperature increase of up to 1 °C on the sunny side. Upward surface sensible and latent heat fluxes are modulated accordingly to compensate for the change in surface solar fluxes. Snow water equivalent and surface albedo both show decreases on the sunny side of the mountains, indicating more snowmelt and hence reduced snow albedo associated with more solar insolation due to mountain effect. Soil moisture increases on the sunny side of the mountains due to enhanced snowmelt, while decreases on the shaded side. Substantial differences are found in the morning hours from 8–10 a.m. and in the afternoon around 3–5 p.m., while differences around noon and in the early morning and late afternoon are comparatively smaller. Variation in the surface energy balance can also affect atmospheric processes, such as cloud fields, through the modulation of vertical thermal structure. Negative changes of up to −40 g m−2 are found in the cloud water path, associated with reductions in the surface insolation over the cloud region. The day-averaged deviations in the surface solar flux are positive over the mountain areas and negative in the valleys, with a range between −12~12 W m−2. Changes in sensible and latent heat fluxes and surface skin temperature follow the solar insolation pattern. Differences in the

  9. High Compressive Stresses Near the Surface of the Sierra Nevada, California

    Science.gov (United States)

    Martel, S. J.; Logan, J. M.; Stock, G. M.

    2012-12-01

    Observations and stress measurements in granitic rocks of the Sierra Nevada, California reveal strong compressive stresses parallel to the surface of the range at shallow depths. New overcoring measurements show high compressive stresses at three locations along an east-west transect through Yosemite National Park. At the westernmost site (west end of Tenaya Lake), the mean compressive stress is 1.9. At the middle site (north shore of Tenaya Lake) the mean compressive stress is 6.8 MPa. At the easternmost site (south side of Lembert Dome) the mean compressive stress is 3.0 MPa. The trend of the most compressive stress at these sites is within ~30° of the strike of the local topographic surface. Previously published hydraulic fracturing measurements by others elsewhere in the Sierra Nevada indicate surface-parallel compressive stresses of several MPa within several tens of meters of the surface, with the stress magnitudes generally diminishing to the west. Both the new and the previously published compressive stress magnitudes are consistent with the presence of sheeting joints (i.e., "exfoliation joints") in the Sierra Nevada, which require lateral compressive stresses of several MPa to form. These fractures are widespread: they are distributed in granitic rocks from the north end of the range to its southern tip and across the width of the range. Uplift along the normal faults of the eastern escarpment, recently measured by others at ~1-2 mm/yr, probably contributes to these stresses substantially. Geodetic surveys reveal that normal faulting flexes a range concave upwards in response to fault slip, and this flexure is predicted by elastic dislocation models. The topographic relief of the eastern escarpment of the Sierra Nevada is 2-4 km, and since alluvial fill generally buries the bedrock east of the faults, the offset of granitic rocks is at least that much. Compressive stresses of several MPa are predicted by elastic dislocation models of the range front

  10. GPS Imaging suggests links between climate, magmatism, seismicity, and tectonics in the Sierra Nevada-Long Valley Caldera-Walker Lane system, western United States

    Science.gov (United States)

    Hammond, W. C.; Blewitt, G.; Kreemer, C.; Smith, K.

    2017-12-01

    The Walker Lane is a region of complex active crustal transtension in the western Great Basin of the western United States, accommodating about 20% of the 50 mm/yr relative motion between the Pacific and North American plates. The Long Valley caldera lies in the central Walker Lane in eastern California, adjacent to the eastern boundary of the Sierra Nevada/Great Valley microplate, and experiences intermittent inflation, uplift, and volcanic unrest from the magma chamber that resides at middle crustal depths. Normal and transform faults accommodating regional tectonic transtension pass by and through the caldera, complicating the interpretation of the GPS-measured strain rate field, estimates of fault slip rates, and seismic hazard. Several dozen continuously recording GPS stations measure strain and uplift in the area with mm precision. They observe that the most recent episode of uplift at Long Valley began in mid-2011, continuing until late 2016, raising the surface by 100 mm in 6 years. The timing of the initiation of uplift coincides with the beginning of severe drought in California. Furthermore, the timing of a recent pause in uplift coincides with the very wet 2016-2017 winter, which saw approximately double normal snow pack. In prior studies, we showed that the timing of changes in geodetically measured uplift rate of the Sierra Nevada coincides with the timing of drought conditions in California, suggesting a link between hydrological loading and Sierra Nevada elevation. Here we take the analysis three steps further to show that changes in Sierra Nevada uplift rate coincide in time with 1) enhanced inflation at the Long Valley caldera, 2) shifts in the patterns and rates of horizontal tensor strain rate, and 3) seismicity patterns in the central Walker Lane. We use GPS solutions from the Nevada Geodetic Laboratory and the new GPS Imaging technique to produce robust animations of the time variable strain and uplift fields. The goals of this work are to

  11. Climate controls on forest productivity along the climate gradient of the western Sierra Nevada

    Science.gov (United States)

    Kelly, A. E.; Goulden, M. L.

    2010-12-01

    The broad climate gradient of the slopes of the western Sierra Nevada mountains supports ecosystems spanning extremes of productivity, biomass, and function. We are using this natural environmental gradient to understand how climate controls NPP, aboveground biomass, species' range limits, and phenology. Our experimental approach combines eddy covariance, sap flow, dendrometer, and litterfall measurements in combination with soil and hydrological data from the Southern Sierra Critical Zone Observatory (SSCZO). We have found that above about 2500 m, forest productivity is limited by winter cold, while below 1200 m, productivity is likely limited by summer drought. The sweet spot between these elevations has a nearly year-long growing season despite a snowpack that persists for as long as six months. Our results show that small differences in temperature can markedly alter the water balance and productivity of mixed conifer forests.

  12. Sierra Nevada snowpack and runoff prediction integrating basin-wide wireless-sensor network data

    Science.gov (United States)

    Yoon, Y.; Conklin, M. H.; Bales, R. C.; Zhang, Z.; Zheng, Z.; Glaser, S. D.

    2016-12-01

    We focus on characterizing snowpack and estimating runoff from snowmelt in high elevation area (>2100 m) in Sierra Nevada for daily (for use in, e.g. flood and hydropower forecasting), seasonal (supply prediction), and decadal (long-term planning) time scale. Here, basin-wide wireless-sensor network data (ARHO, http://glaser.berkeley.edu/wsn/) is integrated into the USGS Precipitation-Runoff Modeling System (PRMS), and a case study of the American River basin is presented. In the American River basin, over 140 wireless sensors have been planted in 14 sites considering elevation gradient, slope, aspect, and vegetation density, which provides spatially distributed snow depth, temperature, solar radiation, and soil moisture from 2013. 800 m daily gridded dataset (PRISM) is used as the climate input for the PRMS. Model parameters are obtained from various sources (e.g., NLCD 2011, SSURGO, and NED) with a regionalization method and GIS analysis. We use a stepwise framework for a model calibration to improve model performance and localities of estimates. For this, entire basin is divided into 12 subbasins that include full natural flow measurements. The study period is between 1982 and 2014, which contains three major storm events and recent severe drought. Simulated snow depth and snow water equivalent (SWE) are initially compared with the water year 2014 ARHO observations. The overall results show reasonable agreements having the Nash-Sutcliffe efficiency coefficient (NS) of 0.7, ranged from 0.3 to 0.86. However, the results indicate a tendency to underestimate the SWE in a high elevation area compared with ARHO observations, which is caused by the underestimated PRISM precipitation data. Precipitation at gauge-sparse regions (e.g., high elevation area), in general, cannot be well represented in gridded datasets. Streamflow estimates of the basin outlet have NS of 0.93, percent bias of 7.8%, and normalized root mean square error of 3.6% for the monthly time scale.

  13. Data on snow chemistry of the Cascade-Sierra Nevada Mountains

    Science.gov (United States)

    Laird, L.B.; Taylor, Howard E.; Lombard, R.E.

    1986-01-01

    Snow chemistry data were measured for solutes found in snow core samples collected from the Cascade-Sierra Nevada Mountains from late February to mid-March 1983. The data are part of a study to assess geographic variations in atmospheric deposition in Washington, Oregon, and California. The constituents and properties include pH and concentrations of hydrogen ion, calcium, magnesium, sodium, potassium, chloride, sulfate, nitrate, fluoride, phosphate, ammonium, iron, aluminum, manganese, copper, cadmium, lead, and dissolved organic carbon. Concentrations of arsenic and bromide were below the detection limit. (USGS)

  14. Groundwater quality in the Yuba River and Bear River Watersheds, Sierra Nevada, California

    Science.gov (United States)

    Fram, Miranda S.; Jasper, Monica; Taylor, Kimberly A.

    2017-09-27

    Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Program’s Priority Basin Project assesses the quality of groundwater resources used for drinking water supply and increases public access to groundwater-quality information. In the Yuba River and Bear River Watersheds of the Sierra Nevada, many rural households rely on private wells for their drinking water supplies. 

  15. Delineation of the High Enthalpy Reservoirs of the Sierra Nevada Volcanic Geothermal System, South-Central Chile

    Science.gov (United States)

    Alam, M.; Muñoz, M.; Parada, M.

    2011-12-01

    Geothermal system associated with the Pleistocene-Holocene Sierra Nevada volcano (SNVGS) in the Araucanía Region of Chile has surface manifestations from the north-western flank of the volcano, up to Manzanar and Malalcahuello. Baños del Toro, located on the northwestern flank of the volcano, has numerous fumaroles and acid pools (acid sulfate waters, T=~90°C, pH=2.1, TDS=3080 mg/L); while Aguas de la Vaca, near the base of the volcano, has a bubbling spring (chloride-sulfate waters, T=~60°C, pH=7.0, TDS=950 mg/L). Five shallow (Geotermia) of the Ministry of Energy and Mining, Government of Chile.

  16. Interannual Variations in Aerosol Sources and Their Impact on Orographic Precipitation over California's Central Sierra Nevada

    Science.gov (United States)

    Creamean, J.; Ault, A. P.; White, A. B.; Neiman, P. J.; Minnis, P.; Prather, K. A.

    2014-12-01

    Aerosols that serve as cloud condensation nuclei (CCN) and ice nuclei (IN) have the potential to profoundly influence precipitation processes. Furthermore, changes in orographic precipitation have broad implications for reservoir storage and flood risks. As part of the CalWater I field campaign (2009-2011), the impacts of aerosol sources on precipitation were investigated in the California Sierra Nevada Mountains. In 2009, the precipitation collected on the ground was influenced by both local biomass burning and long-range transported dust and biological particles, while in 2010, by mostly local sources of biomass burning and pollution, and in 2011 by mostly long-range transport of dust and biological particles from distant sources. Although vast differences in the sources of residues were observed from year-to-year, dust and biological residues were omnipresent (on average, 55% of the total residues combined) and were associated with storms consisting of deep convective cloud systems and larger quantities of precipitation initiated in the ice phase. Further, biological residues were dominant during storms with relatively warm cloud temperatures (up to -15°C), suggesting biological components were more efficient IN than mineral dust. On the other hand, when precipitation quantities were lower, local biomass burning and pollution residues were observed (on average 31% and 9%, respectively), suggesting these residues potentially served as CCN at the base of shallow cloud systems and that lower level polluted clouds of storm systems produced less precipitation than non-polluted (i.e., marine) clouds. The direct connection of the sources of aerosols within clouds and precipitation type and quantity can be used in models to better assess how local emissions versus long-range transported dust and biological aerosols play a role in impacting regional weather and climate, ultimately with the goal of more accurate predictive weather forecast models and water resource

  17. Extent, timing, and climatic significance of latest Pleistocene and Holocene glaciation in the Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Douglas Howe [Univ. of Washington, Seattle, WA (United States)

    1995-01-01

    Despite more than a century of study, scant attention has been paid to the glacial record in the northern end of the Sierra Nevada, and to the smaller moraines deposited after the retreat of the Tioga (last glacial maximum) glaciers. Equilibrium-line altitude (ELA) estimates of the ice fields indicate that the Tioga ELA gradients there are consistent with similar estimates for the southern half of the range, and with an intensification of the modern temperature/precipitation pattern in the region. The Recess Peak advance has traditionally been considered to be mid-Neoglacial age, about 2--3,000 yr B.P., on the basis of relative weathering estimates. Sediment cores of lakes dammed behind moraines correlative with Recess Peak in four widely spaced sites yields a series of high-resolution AMS radiocarbon dates which demonstrate that Recess Peak glaciers retreated before ~13,100 cal yr B.P.. This minimum limiting age indicates that the advance predates the North Atlantic Younger Dryas cooling. It also implies that there have been no advances larger than the Matthes in the roughly 12,000 year interval between it and the Recess Peak advance. This finding casts doubt on several recent studies that claim Younger Dryas glacier advances in western North America. The 13,100 cal yr B.P. date is also a minimum age for deglaciation of the sample sites used to calibrate the in situ production rates of cosmogenic 10Be and 26Al. The discrepancy between this age and the 11,000 cal yr B.P. exposure age assumed in the original calibration introduces a large (> 19%) potential error in late-Pleistocene exposure ages calculated using these production rates.

  18. Spatiotemporal patterns of precipitation inferred from streamflow observations across the Sierra Nevada mountain range

    Science.gov (United States)

    Henn, Brian; Clark, Martyn P.; Kavetski, Dmitri; Newman, Andrew J.; Hughes, Mimi; McGurk, Bruce; Lundquist, Jessica D.

    2018-01-01

    Given uncertainty in precipitation gauge-based gridded datasets over complex terrain, we use multiple streamflow observations as an additional source of information about precipitation, in order to identify spatial and temporal differences between a gridded precipitation dataset and precipitation inferred from streamflow. We test whether gridded datasets capture across-crest and regional spatial patterns of variability, as well as year-to-year variability and trends in precipitation, in comparison to precipitation inferred from streamflow. We use a Bayesian model calibration routine with multiple lumped hydrologic model structures to infer the most likely basin-mean, water-year total precipitation for 56 basins with long-term (>30 year) streamflow records in the Sierra Nevada mountain range of California. We compare basin-mean precipitation derived from this approach with basin-mean precipitation from a precipitation gauge-based, 1/16° gridded dataset that has been used to simulate and evaluate trends in Western United States streamflow and snowpack over the 20th century. We find that the long-term average spatial patterns differ: in particular, there is less precipitation in the gridded dataset in higher-elevation basins whose aspect faces prevailing cool-season winds, as compared to precipitation inferred from streamflow. In a few years and basins, there is less gridded precipitation than there is observed streamflow. Lower-elevation, southern, and east-of-crest basins show better agreement between gridded and inferred precipitation. Implied actual evapotranspiration (calculated as precipitation minus streamflow) then also varies between the streamflow-based estimates and the gridded dataset. Absolute uncertainty in precipitation inferred from streamflow is substantial, but the signal of basin-to-basin and year-to-year differences are likely more robust. The findings suggest that considering streamflow when spatially distributing precipitation in complex terrain

  19. Snowmelt response to simulated warming across a large elevation gradient, southern Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    K. N. Musselman

    2017-12-01

    Full Text Available In a warmer climate, the fraction of annual meltwater produced at high melt rates in mountainous areas is projected to decline due to a contraction of the snow-cover season, causing melt to occur earlier and under lower energy conditions. How snowmelt rates, including extreme events relevant to flood risk, may respond to a range of warming over a mountain front is poorly known. We present a model sensitivity study of snowmelt response to warming across a 3600 m elevation gradient in the southern Sierra Nevada, USA. A snow model was run for three distinct years and verified against extensive ground observations. To simulate the impact of climate warming on meltwater production, measured meteorological conditions were modified by +1 to +6 °C. The total annual snow water volume exhibited linear reductions (−10 % °C−1 consistent with previous studies. However, the sensitivity of snowmelt rates to successive degrees of warming varied nonlinearly with elevation. Middle elevations and years with more snowfall were prone to the largest reductions in snowmelt rates, with lesser changes simulated at higher elevations. Importantly, simulated warming causes extreme daily snowmelt (99th percentiles to increase in spatial extent and intensity, and shift from spring to winter. The results offer insight into the sensitivity of mountain snow water resources and how the rate and timing of water availability may change in a warmer climate. The identification of future climate conditions that may increase extreme melt events is needed to address the climate resilience of regional flood control systems.

  20. Ecología de la fauna silvestre de la sierra nevada y la Sierra del Ajusco

    Directory of Open Access Journals (Sweden)

    D. Granados Sánchez

    2004-01-01

    Full Text Available Se presenta un estudio sobre la fauna silvestre de la Sierra del Ajusco y la Sierra Nevada, localizadas dentro de la Faja Volcánica Transmexicana (FVT, en la porción oriental del límite meridional de la Cuenca de México. La enorme riqueza biológica de esta zona que rodea la zona metropolitana de la ciudad de México, uno de los mayores complejos urbanos del mundo, ha sobrevivido durante décadas al impacto de la urbanización de las áreas forestales, explotación de recursos naturales, contaminación, cacería, incendios y pastoreo. A pesar de esto, se desconocen muchos de los factores que regulan la dinámica de los ecosistemas en esta región. Con relación a la fauna silvestre la carencia de información es mucho más evidente, aspectos elementales como la diversidad de especies, las interacciones ecológicas, la función de los organismos en el ecosistema, las condiciones de estrés a que están sometidos, han sido poco explorados. En esta investigación se recurrió a observaciones de campo y a la consulta de diferentes fuentes bibliográficas para estimar la riqueza de especies de mamíferos, aves, reptiles y anfibios; las relaciones ecológicas entre los mismos y las consecuencias de la modificación de su hábitat producto de las actividades humanas.

  1. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Abstract Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988–1990 and 2009–2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:25878552

  2. Dataset of Phenology of Mediterranean high-mountain meadows flora (Sierra Nevada, Spain).

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Sánchez-Rojas, Cristina Patricia; Zamora, Regino; Pérez-Pérez, Ramón; Bonet, Francisco Javier

    2015-01-01

    Sierra Nevada mountain range (southern Spain) hosts a high number of endemic plant species, being one of the most important biodiversity hotspots in the Mediterranean basin. The high-mountain meadow ecosystems (borreguiles) harbour a large number of endemic and threatened plant species. In this data paper, we describe a dataset of the flora inhabiting this threatened ecosystem in this Mediterranean mountain. The dataset includes occurrence data for flora collected in those ecosystems in two periods: 1988-1990 and 2009-2013. A total of 11002 records of occurrences belonging to 19 orders, 28 families 52 genera were collected. 73 taxa were recorded with 29 threatened taxa. We also included data of cover-abundance and phenology attributes for the records. The dataset is included in the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area.

  3. Vertical Distribution of Ozone and Nitric Acid Vapor on the Mammoth Mountain, Eastern Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    Andrzej Bytnerowicz

    2002-01-01

    Full Text Available In August and September 1999 and 2000, concentrations of ozone (O3 and nitric acid vapor (HNO3 were monitored at an elevation gradient (2184–3325 m on the Mammoth Mountain, eastern Sierra Nevada, California. Passive samplers were used for monitoring exposure to tropospheric O3 and HNO3 vapor. The 2-week average O3 concentrations ranged between 45 and 72 ppb, while HNO3 concentrations ranged between 0.06 and 0.52 μg/m3. Similar ranges of O3 and HNO3 were determined for 2 years of the study. No clear effects of elevation on concentrations of the two pollutants were detected. Concentrations of HNO3 were low and at the background levels expected for the eastern Sierra Nevada, while the measured concentrations of O3 were elevated. High concentrations of ozone in the study area were confirmed with an active UV absorption O3 monitor placed at the Mammoth Mountain Peak (September 5–14, 2000, average 24-h concentration of 56 ppb.

  4. Cenozoic thermal evolution of the central Sierra Nevada, California, from (U sbnd Th)/He thermochronometry

    Science.gov (United States)

    House, M. A.; Wernicke, B. P.; Farley, K. A.; Dumitru, T. A.

    1997-10-01

    Apatite(U sbnd Th)/He cooling ages are reported for igneous apatite samples from the central Sierra Nevada and compared to published apatite fission track ages and track length data from the same mineral separates. Helium ages are youngest at low elevations and increase systematically toward higher elevations, ranging from 43 to 84 Ma at Yosemite Valley, 32 to 74 Ma at Kings River Canyon, and 23 to 75 Ma at Mt. Whitney. Helium ages from high elevation samples are generally concordant with corresponding fission track ages, while lower elevation helium ages are substantially younger. Cooling histories inferred from present laboratory derived fission track annealing and helium diffusion models do not match well, suggesting that either helium diffusion rates or fission track annealing rates are miscalibrated at temperatures below about 60°C for geologic exposure periods. Unlike the fission track results, the helium data do not indicate a very low geothermal gradient in the Sierra Nevada during early to middle Tertiary time.

  5. Thermal evolution and exhumation of deep-level batholithic exposures, southernmost Sierra Nevada, California

    Science.gov (United States)

    Saleeby, J.; Farley, K.A.; Kistler, R.W.; Fleck, R.J.

    2007-01-01

    The Tehachapi complex lies at the southern end of the Sierra Nevada batholith adjacent to the Neogene-Quaternary Garlock fault. The complex is composed principally of high-pressure (8-10 kbar) Cretaceous batholithic rocks, and it represents the deepest exposed levels of a continuous oblique crustal section through the southern Sierra Nevada batholith. Over the southern ???100 km of this section, structural/petrologic continuity and geochronological data indicate that ???35 km of felsic to intermediate-composition crust was generated by copious arc magmatism primarily between 105 and 99 Ma. In the Tehachapi complex, these batholithic rocks intrude and are bounded to the west by similar-composition gneissic-textured high-pressure batholithic rocks emplaced at ca. 115-110 Ma. This lower crustal complex is bounded below by a regional thrust system, which in Late Cretaceous time tectonically eroded the underlying mantle lithosphere, and in series displaced and underplated the Rand Schist subduction assemblage by low-angle slip from the outboard Franciscan trench. Geophysical and mantle xenolith studies indicate that the remnants of this shallow subduction thrust descend northward through the crust and into the mantle, leaving the mantle lithosphere intact beneath the greater Sierra Nevada batholith. This north-dipping regional structure records an inflection in the Farallon plate, which was segmented into a shallow subduc-tion trajectory to the south and a normal steeper trajectory to the north. We combine new and published data from a broad spectrum of thermochronom-eters that together form a coherent data array constraining the thermal evolution of the complex. Integration of these data with published thermobarometric and petro-genetic data also constrains the tectonically driven decompression and exhumation history of the complex. The timing of arc magmatic construction of the complex, as denoted above, is resolved by a large body of U/Pb zircon ages. High

  6. 77 FR 45 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List Sierra Nevada...

    Science.gov (United States)

    2012-01-03

    ... them at risk of attack, death, or diseases such as rabies, sarcoptic mange, canine distemper, and... canine distemper, rabies, and sarcoptic mange to Sierra Nevada red fox (Perrine et al. 2010, p. 28... 2011, pp. 54-60), an outbreak of canine distemper or other lethal disease, as well as predation by...

  7. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

    Science.gov (United States)

    R. Cisneros; A. Bytnerowicz; D. Schweizer; S. Zhong; S. Traina; D.H. Bennett

    2010-01-01

    Two-week average concentrations of ozone (O3), nitric acid vapor (HNO3) and ammonia (NH3) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were...

  8. Modeling the influence of precipitation and nitrogen deposition on forest understory fuel connectivity in Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    M. Hurteau; M. North; T. Foines

    2009-01-01

    Climate change models for California’s Sierra Nevada predict greater inter-annual variability in precipitation over the next 50 years. These increases in precipitation variability coupled with increases in nitrogen deposition fromfossil fuel consumption are likely to result in increased productivity levels and significant increases in...

  9. First record for the river turtle Kinosternon leucostomum (DUMERIL & BIBRON 1851, from the Sierra Nevada de Santa Marta foothills

    Directory of Open Access Journals (Sweden)

    Juan Mendoza Roldan

    2017-07-01

    Full Text Available The river turtle (Kinosternon leucostomum, was first reported for the department of Guajira in 2011, found in the foothills of the Serranía de Perijá (GALVIS-PEÑUELA et al., 2011. Our observations constitute the first record for the Sierra Nevada de Santamarta Massif and the second distribution record within the department of Guajira, Colombian Caribbean.

  10. Multi-scale evaluation of the environmental controls on burn probability in a southern Sierra Nevada landscape

    Science.gov (United States)

    Sean A. Parks; Marc-Andre Parisien; Carol Miller

    2011-01-01

    We examined the scale-dependent relationship between spatial fire likelihood or burn probability (BP) and some key environmental controls in the southern Sierra Nevada, California, USA. Continuous BP estimates were generated using a fire simulation model. The correspondence between BP (dependent variable) and elevation, ignition density, fuels and aspect was evaluated...

  11. Content of chemical elements in tree rings of lodgepole pine and whitebark pine from a subalpine Sierra Nevada forest

    Science.gov (United States)

    David L. Peterson; Darren R. Anderson

    1990-01-01

    The wood of lodgepole pines and whitebark pines from a high elevation site in the east central Sierra Nevada of California was analyzed for chemical content to determine whether there were any temporal patterns of chemical distribution in tree rings. Cores were taken from 10 trees of each species and divided into 5-year increments for chemical analysis. Correlation...

  12. Dispersal limitation does not control high elevational distribution of alien plant species in the southern Sierra Nevada, California

    Science.gov (United States)

    Rundel, Philip W.; Keeley, Jon E.

    2016-01-01

    Patterns of elevational distribution of alien plant species in the southern Sierra Nevada of California were used to test the hypothesis that alien plant species invading high elevations around the world are typically climate generalists capable of growing across a wide elevational range. The Sierra Nevada has been heavily impacted for more than a century and a half, first by heavy grazing up into high elevation meadows, followed by major logging, and finally, by impacts associated with recreational use. The comparative elevational patterns of distribution and growth form were compared for native and alien plant species in the four families (Asteraceae, Brassicaceae, Fabaceae, and Poaceae) that contribute the majority of naturalized aliens in the study area. The distribution of realized climatic niche breadth, as measured by elevational range of occurrence, was virtually identical for alien and native species, with both groups showing a roughly Gaussian distribution peaking with species whose range covers a span of 1500–1999 m. In contrast to alien species, which only rarely occurred at higher elevations, native species showed a distribution of upper elevation limits peaking at 3000–3499 m, an elevation that corresponds to the zone of upper montane and subalpine forests. Consistent with a hypothesis of abiotic limitations, only a few alien species have been ecologically successful invaders at subalpine and alpine elevations above 2500 m. The low diversity of aliens able to become established in these habitats is unlikely due to dispersal limitations, given the long history of heavy grazing pressure at high elevations across this region. Instead, this low diversity is hypothesized to be a function of life history traits and multiple abiotic stresses that include extremes of cold air and soil temperature, heavy snowfall, short growing seasons, and low resource availability. These findings have significant implications for resource managers.

  13. The Relationships Between Insoluble Precipitation Residues, Clouds, and Precipitation Over California's Southern Sierra Nevada During Winter Storms

    Science.gov (United States)

    Creamean, Jessie M.; White, Allen B.; Minnis, Patrick; Palikonda, Rabindra; Spangenberg, Douglas A.; Prather, Kimberly A.

    2016-01-01

    Ice formation in orographic mixed-phase clouds can enhance precipitation and depends on the type of aerosols that serve as ice nucleating particles (INP). The resulting precipitation from these clouds is a viable source of water, especially for regions such as the California Sierra Nevada. Thus, a better understanding of the sources of INP that impact orographic clouds is important for assessing water availability in California. This study presents a multi-site, multi-year analysis of single particle insoluble residues in precipitation samples that likely influenced cloud ice and precipitation formation above Yosemite National Park. Dust and biological particles represented the dominant fraction of the residues (64% on average). Cloud glaciation, determined using GOES satellite observations, not only depended on high cloud tops (greater than 6.2 km) and low temperatures (less than -26 C), but also on the composition of the dust and biological residues. The greatest prevalence of ice-phase clouds occurred in conjunction with biologically-rich residues and mineral dust rich in calcium, followed by iron and aluminosilicates. Dust and biological particles are known to be efficient INP, thus these residues are what likely influenced ice formation in clouds above the sites and subsequent precipitation quantities reaching the surface during events with similar meteorology. The goal of this study is to use precipitation chemistry information to gain a better understanding of the potential sources of INP in the south-central Sierra Nevada, where cloud-aerosol-precipitation interactions are under-studied and where mixed-phase orographic clouds represent a key element in the generation of precipitation and thus the water supply in California.

  14. Inferring ecological relationships from occupancy patterns for California Black Rails in the Sierra Nevada foothills

    Science.gov (United States)

    Richmond, Orien Manu Wright

    The secretive California Black Rail (Laterallus jamaicensis coturniculus ) has a disjunct and poorly understood distribution. After a new population was discovered in Yuba County in 1994, we conducted call playback surveys from 1994--2006 in the Sierra foothills and Sacramento Valley region to determine the distribution and residency of Black Rails, estimate densities, and obtain estimates of site occupancy and detection probability. We found Black Rails at 164 small, widely scattered marshes distributed along the lower western slopes of the Sierra Nevada foothills, from just northeast of Chico (Butte County) to Rocklin (Placer County). Marshes were surrounded by a matrix of unsuitable habitat, creating a patchy or metapopulation structure. We observed Black Rails nesting and present evidence that they are year-round residents. Assuming perfect detectability we estimated a lower-bound mean Black Rail density of 1.78 rails ha-1, and assuming a detection probability of 0.5 we estimated a mean density of 3.55 rails ha-1. We test if the presence of the larger Virginia Rail (Laterallus limicola) affects probabilities of detection or occupancy of the smaller California Black Rail in small freshwater marshes that range in size from 0.013-13.99 ha. We hypothesized that Black Rail occupancy should be lower in small marshes when Virginia Rails are present than when they are absent, because resources are presumably more limited and interference competition should increase. We found that Black Rail detection probability was unaffected by the detection of Virginia Rails, while, surprisingly, Black and Virginia Rail occupancy were positively associated even in small marshes. The average probability of Black Rail occupancy was higher when Virginia Rails were present (0.74 +/- 0.053) than when they were absent (0.36 +/- 0.069), and for both species occupancy increased with marsh size. We assessed the impact of winter (November-May) cattle grazing on occupancy of California Black

  15. Clustering of velocities in a GPS network spanning the Sierra Nevada Block, the northern Walker Lane Belt, and the Central Nevada Seismic Belt, California-Nevada

    Science.gov (United States)

    Savage, James C.; Simpson, Robert W.

    2013-01-01

    The deformation across the Sierra Nevada Block, the Walker Lane Belt, and the Central Nevada Seismic Belt (CNSB) between 38.5°N and 40.5°N has been analyzed by clustering GPS velocities to identify coherent blocks. Cluster analysis determines the number of clusters required and assigns the GPS stations to the proper clusters. The clusters are shown on a fault map by symbols located at the positions of the GPS stations, each symbol representing the cluster to which the velocity of that GPS station belongs. Fault systems that separate the clusters are readily identified on such a map. Four significant clusters are identified. Those clusters are strips separated by (from west to east) the Mohawk Valley-Genoa fault system, the Pyramid Lake-Wassuk fault system, and the Central Nevada Seismic Belt. The strain rates within the westernmost three clusters approximate simple right-lateral shear (~13 nstrain/a) across vertical planes roughly parallel to the cluster boundaries. Clustering does not recognize the longitudinal segmentation of the Walker Lane Belt into domains dominated by either northwesterly trending, right-lateral faults or northeasterly trending, left-lateral faults.

  16. Sierra Nevada serpentinites. An important element in the architectonic heritage of Granada (Spain).

    Science.gov (United States)

    Navarro, Rafael; Pereira, Dolores; Rodríguez-Navarro, Carlos; Sebastián-Pardo, Eduardo

    2013-04-01

    Serpentinites are widely used in historic buildings in the whole world, from Ancient Greek or Egypt to more recent colonial buildings in the USA. Serpentinites from Sierra Nevada (S of Spain) have been traditionally used as ornamental elements in historic buildings of Granada city, both indoors and outdoors. The Cathedral, Carlos V Palace, Royal Chancery and some others are good examples of their use. Some other important cases can be found outside Granada, like El Escorial monastery, Las Salesas Reales convent, etc… all of them part of Madrid architectonic heritage. There are two quarries located in Sierra Nevada that supplied all the material to make the different elements in the cited buildings. In this work, a thorough characterization of the main serpentinites from Sierra Nevada, their uses, and their state of conservation in selected buildings from Granada has been performed. Samples from the main original quarry and from one historical building (Real Chancillería) have been analysed, determining the mineralogical and geochemical composition, texture, water parameters (absorption, porosity, density) and possible alteration by salt formation. It has been observed that the mineralogical and geochemical compositions are similar in both sets of samples, although the ones coming from the historical building show a highly advanced state of alteration. Regarding physical and mechanical parameters, samples from the quarry have very low water absorption values, while the porosity of serpentinites sampled from the Real Chancillería is comparatively much higher. We explain this difference as due to the weathering of the emplaced serpentinites by salt crystallization processes (mainly gypsum or epsomite), that generate strong internal pressures causing the disintegration of the whole natural stone. In addition, the increase of the porosity can be caused by dissolution processes related to the presence of acid solutions related to oxidation and hydrolysis of iron

  17. Making up for lost snow: lessons from a warming Sierra Nevada

    Science.gov (United States)

    Bales, R. C.

    2017-12-01

    Snowpack- and glacier-dependent river basins are home to over 1.2 billion people, one-sixth of the world's current population. These areas face severe challenges in a warmer climate, as declines in snow resources put more pressure on dams and groundwater. Closer to home, the seasonal snowpacks in California's Sierra Nevada provide water storage to both sustain productive forests and support the world's 6th largest economy. Rivers draining the Sierra supply the state's large cities, plus agricultural areas that provide nearly half of the nation's fruits and vegetables. Water storage is central to water security, especially given California's hot dry summers and high interannual variability in precipitation. On average seasonal snowpacks store about half as much water as do dams on Sierra rivers; and both the magnitude and duration of snowpack storage are decreasing. Precipitation amount and snow accumulation across the mountains in any given day, month or year remain uncertain. As historical index-statistical methods for hydrologic forecasts give way to tools based on mass and energy balances distributed across the landscape, opportunities are arising to broadly implement spatial measurements of snowpack storage and the equally important regolith-water storage. Advances in applying satellite and aircraft remote sensing, plus spatially distributed wireless-sensor networks, are filling this need. These same unprecedented data are driving process understanding to improve knowledge of snow-energy-forest interactions, snowmelt estimates, and hydrologic forecasts for hydropower, water supply, and flood control. Estimating the value of snowpacks and how they are changing provides a baseline for evaluating investments in restoration of headwater forests that will affect snowmelt runoff, and in providing replacement storage as snow declines. With California facing billions of dollars of green and grey infrastructure improvements, which must be compatible with the state

  18. Some additional observations on inclusions in the granitic rocks of the Sierra Nevada

    Science.gov (United States)

    Dodge, F.C.W.; Kistler, R.W.

    1990-01-01

    Microgranular quartz diorite and diorite inclusions are widespread in central Sierra Nevada granitoid rocks and are almost exclusively restricted to hornblende-bearing rocks, most commonly felsic tonalites and mafic granodiorites. The Nd-Sm and Rb-Sr systematics indicate that most inclusions were in isotopic equilibrium with enclosing materials at the time of formation. Silica contents of inclusions and granitoids are contiguous, but inclusions generally contain less than, and granitoids more than, 60% SiO2. Ferric oxide and H2O+ trends relative to SiO2 suggests many inclusions formed as concentrations of hydrous mafic minerals. Variation of other major element oxides and trace elements support this inference. Most inclusions represent fragmented crystal accumulations of early-formed, near-liquidus minerals generated from these previously mixed magmas. -from Authors

  19. Detecting Drought-Induced Tree Mortality in Sierra Nevada Forests with Time Series of Satellite Data

    Directory of Open Access Journals (Sweden)

    Sarah Byer

    2017-09-01

    Full Text Available A five-year drought in California led to a significant increase in tree mortality in the Sierra Nevada forests from 2012 to 2016. Landscape level monitoring of forest health and tree dieback is critical for vegetation and disaster management strategies. We examined the capability of multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS in detecting and explaining the impacts of the recent severe drought in Sierra Nevada forests. Remote sensing metrics were developed to represent baseline forest health conditions and drought stress using time series of MODIS vegetation indices (VIs and a water index. We used Random Forest algorithms, trained with forest aerial detection surveys data, to detect tree mortality based on the remote sensing metrics and topographical variables. Map estimates of tree mortality demonstrated that our two-stage Random Forest models were capable of detecting the spatial patterns and severity of tree mortality, with an overall producer’s accuracy of 96.3% for the classification Random Forest (CRF and a RMSE of 7.19 dead trees per acre for the regression Random Forest (RRF. The overall omission errors of the CRF ranged from 19% for the severe mortality class to 27% for the low mortality class. Interpretations of the models revealed that forests with higher productivity preceding the onset of drought were more vulnerable to drought stress and, consequently, more likely to experience tree mortality. This method highlights the importance of incorporating baseline forest health data and measurements of drought stress in understanding forest response to severe drought.

  20. Onset and Multiple Fluctuations of Holocene Glaciation in the Sierra Nevada, California

    Science.gov (United States)

    Bowerman, N. D.; Clark, D. H.

    2004-12-01

    Multiple sediment cores from two paternoster tarns (First and Second lakes) in North Fork Big Pine Creek, Sierra Nevada, preserve the most detailed and complete record of Holocene glaciation yet recovered in the range; they indicate that the glacier was absent during the early Holocene, reformed in the late Holocene, and experienced several expansions and contractions, culminating with the Matthes maximum during the last ˜200 years. The lakes are fed by outwash from the Palisade Glacier, the largest ( ˜1.3 km2) and presumably longest-lived glacier in the Sierra Nevada, and capture essentially all of the rock flour produced by the glacier. Distinct late-Holocene (Matthes) and late-Pleistocene (Recess Peak) moraines lie between the modern glacier and the lakes. Thus, the lakes have received continuous sedimentation since the retreat of the Tioga glacier ( ˜15,000 yr B.P.), and therefore capture rock flour related to all subsequent advances. First and Second lakes occupy relatively deep bedrock basins at 3036 m and 3066 m asl., respectively. Third Lake, a shallow (rock flour (outwash) from the upstream Palisade Glacier, most likely related to formation and expansions of the glacier in the late Holocene. The maximum peak at the top of the cores confirms the moraine record, which indicates that the maximum Holocene advance of Sierran glaciers occurred during the late Little Ice Age (last ˜200 yr) At least one tephra layer, possibly related to the Mono/Inyo dome complexes, occurs in the middle depths of the First Lake cores. Other narrow peaks in MS may also be associated with tephra deposits. Ongoing detailed analyses of the sediments, including AMS radiocarbon dating, visual and x-ray imaging, particle size analysis, organic content, tephrochronology, diatom assemblages, and palynology will constrain the timing and character of the environmental fluctuations related to the rock-flour flux. We will present results of these analyses at the meeting.

  1. A quantitative evaluation of the conservation umbrella of spotted owl management areas in the Sierra Nevada.

    Directory of Open Access Journals (Sweden)

    Ryan D Burnett

    Full Text Available Whether by design or default, single species management often serves as an umbrella for species with similar habitat requirements. In recent decades the focus of National Forest management in the Sierra Nevada of California has shifted towards increasing closed canopy mature forest conditions through the protection of areas occupied by the California Spotted Owl (Strix occidentalis occidentalis. To evaluate the implications of these habitat changes and the potential umbrella resulting from a system of owl reserves on the broader avian community, we estimated occupancy of birds inside and outside of Spotted Owl Home Range Core Areas in northeastern California. We used point count data in a multi-species hierarchical Bayesian model incorporating the detection history of 81 species over a two-year time period (2005-2006. A small set of vegetation cover and topography covariates were included in the model to account for broad differences in habitat conditions, as well as a term identifying whether or not a site was within a Core Area. Seventeen species had a negative Core Area effect, seven had a positive effect, and the rest were not significant. Estimated species richness was significantly different with 23.1 species per 100 m radius circle outside Core Areas and 21.7 inside Core Areas. The majority of the species negatively associated with Core Areas are tied to early successional and other disturbance-dependent habitats. Conservation and climate vulnerability rankings were mixed. On average we found higher scores (greater risk for the species positively associated with Core Areas, but a larger number of species with the highest scores were negatively associated with Core Areas. We discuss the implications for managing the Sierra Nevada ecosystem and illustrate the role of monitoring broader suites of species in guiding management of large complex ecosystems.

  2. Geologic Map of the Tower Peak Quadrangle, Central Sierra Nevada, California

    Science.gov (United States)

    Wahrhaftig, Clyde

    2000-01-01

    Introduction The Tower Peak quadrangle, which includes northernmost Yosemite National Park, is located astride the glaciated crest of the central Sierra Nevada and covers an exceptionally well-exposed part of the Sierra Nevada batholith. Granitic plutonic rocks of the batholith dominate the geology of the Tower Peak quadrangle, and at least 18 separate pre-Tertiary intrusive events have been identified. Pre-Cretaceous metamorphic rocks crop out in the quadrangle in isolated roof pendants and septa. Tertiary volcanic rocks cover granitic rocks in the northern part of the quadrangle, but are not considered in this brief summary. Potassium-argon (K-Ar) age determinations for plutonic rocks in the quadrangle range from 83 to 96 million years (Ma), including one of 86 Ma for the granodiorite of Lake Harriet (Robinson and Kistler, 1986). However, a rubidium-strontium whole-rock isochron age of 129 Ma has been obtained for the Lake Harriet pluton (Robinson and Kistler, 1986), which field evidence indicates is the oldest plutonic body within the quadrangle. This suggests that some of the K-Ar ages record an episode of resetting during later thermal events and are too young. The evidence indicates that all the plutonic rocks are of Cretaceous age, with the youngest being the Cathedral Peak Granodiorite at about 83 Ma. The pre-Tertiary rocks of the Tower Peak quadrangle fall into two groups: (1) an L-shaped area of older plutonic and metamorphic rocks, 3 to 10 km wide, that extends diagonally both northeast and southeast from near the center of the quadrangle; and (2) a younger group of large, probably composite intrusions that cover large areas in adjacent quadrangles and extend into the Tower Peak quadrangle from the east, north, and southwest.

  3. Principal Hydrologic Responses to Climatic and Geologic Variability in the Sierra Nevada, California

    Directory of Open Access Journals (Sweden)

    David H. Peterson

    2008-02-01

    Full Text Available Sierra Nevada snowpack is a critical water source for California’s growing population and agricultural industry. However, because mountain winters and springs are warming, on average, precipitation as snowfall relative to rain is decreasing, and snowmelt is earlier. The changes are stronger at mid-elevations than at higher elevations. The result is that the water supply provided by snowpack is diminishing. In this paper, we describe principal hydrologic responses to climatic and spatial geologic variations as gleaned from a series of observations including snowpack, stream-flow, and bedrock geology. Our analysis focused on peak (maximum and base (minimum daily discharge of the annual snowmelt-driven hydrographs from 18 Sierra Nevada watersheds and 24 stream gage locations using standard correlation methods. Insights into the importance of the relative magnitudes of peak flow and soil water storage led us to develop a hydrologic classification of mountain watersheds based on runoff versus base flow as a percentage of peak flow. Our findings suggest that watersheds with a stronger base flow response store more soil water than watersheds with a stronger peak-flow response. Further, the influence of antecedent wet or dry years is greater in watersheds with high base flow, measured as a percentage of peak flow. The strong correlation between 1 the magnitude of peak flow, and 2 snow water equivalent can be used to predict peak flow weeks in advance. A weaker but similar correlation can be used to predict the magnitude of base flow months in advance. Most of the watersheds show a trend that peak flow is occurring earlier in the year.

  4. Effects of Climate and Fuels Management on Wildfire Occurrence, Size, Severity and Emissions in the Sierra Nevada

    Science.gov (United States)

    Westerling, A. L.; Fites, J. A.; Keyser, A.

    2015-12-01

    Annual wildfire burned area in federally managed Sierra Nevada forests has increased by more than 10,000 ha per decade since the early 1970s. At the same time, recent years have seen some extremely large fires compared to the historical record, with significant areas of moderate to high severity fire (e.g., McNally 2002, Rim 2013, King 2014 fires). Changes to fuels and fire regimes due to fire suppression and land use, as well as warming temperatures and the occurrence of drought, are thought to be significant factors contributing to increased risks of large, severe fires in Sierra Nevada forests. Over 70% of the vegetated area in federally managed forests in the Sierra Nevada is classified as having altered fuels and fire regimes, while average annual temperature in the Sierra Nevada has been above the long term mean for all but four years in the past two decades. As climate is expected to continue warming for decades to come, we explored fuels management scenarios as the primary tools available to modify risks of large, severe wildfires. We developed experimental statistical models of fire occurrence, fire size, and high severity burned area, to explore the interaction between climate and altered fuels conditions. These models were applied to historical climate conditions, a sample of future climate projections, and to both current fuels conditions and a range of scenarios for fuels treatments. Emissions from wildfires were estimated using the Fire Inventory from the National Center for Atmospheric Research. Our models project that average annual burned area in the Sierra Nevada will more than double by mid-century. Similarly, particulate and other pollution emissions from Sierra Nevada wildfires are projected to more than double, even if future fire severity does not change. Fuels treatment scenarios significantly reduced simulated future burned area and emissions below untreated projections. High severity burned area responded to both climate and fuels

  5. Measured Black Carbon Deposition on the Sierra Nevada Snow Pack and Implication for Snow Pack Retreat

    Energy Technology Data Exchange (ETDEWEB)

    Hadley, O.L.; Corrigan, C.E.; Kirchstetter, T.W.; Cliff, S.S.; Ramanathan, V.

    2010-01-12

    Modeling studies show that the darkening of snow and ice by black carbon deposition is a major factor for the rapid disappearance of arctic sea ice, mountain glaciers and snow packs. This study provides one of the first direct measurements for the efficient removal of black carbon from the atmosphere by snow and its subsequent deposition to the snow packs of California. The early melting of the snow packs in the Sierras is one of the contributing factors to the severe water problems in California. BC concentrations in falling snow were measured at two mountain locations and in rain at a coastal site. All three stations reveal large BC concentrations in precipitation, ranging from 1.7 ng/g to 12.9 ng/g. The BC concentrations in the air after the snow fall were negligible suggesting an extremely efficient removal of BC by snow. The data suggest that below cloud scavenging, rather than ice nuclei, was the dominant source of BC in the snow. A five-year comparison of BC, dust, and total fine aerosol mass concentrations at multiple sites reveals that the measurements made at the sampling sites were representative of large scale deposition in the Sierra Nevada. The relative concentration of iron and calcium in the mountain aerosol indicates that one-quarter to one-third of the BC may have been transported from Asia.

  6. Simulating high spatial resolution high severity burned area in Sierra Nevada forests for California Spotted Owl habitat climate change risk assessment and management.

    Science.gov (United States)

    Keyser, A.; Westerling, A. L.; Jones, G.; Peery, M. Z.

    2017-12-01

    Sierra Nevada forests have experienced an increase in very large fires with significant areas of high burn severity, such as the Rim (2013) and King (2014) fires, that have impacted habitat of endangered species such as the California spotted owl. In order to support land manager forest management planning and risk assessment activities, we used historical wildfire histories from the Monitoring Trends in Burn Severity project and gridded hydroclimate and land surface characteristics data to develope statistical models to simulate the frequency, location and extent of high severity burned area in Sierra Nevada forest wildfires as functions of climate and land surface characteristics. We define high severity here as BA90 area: the area comprising patches with ninety percent or more basal area killed within a larger fire. We developed a system of statistical models to characterize the probability of large fire occurrence, the probability of significant BA90 area present given a large fire, and the total extent of BA90 area in a fire on a 1/16 degree lat/lon grid over the Sierra Nevada. Repeated draws from binomial and generalized pareto distributions using these probabilities generated a library of simulated histories of high severity fire for a range of near (50 yr) future climate and fuels management scenarios. Fuels management scenarios were provided by USFS Region 5. Simulated BA90 area was then downscaled to 30 m resolution using a statistical model we developed using Random Forest techniques to estimate the probability of adjacent 30m pixels burning with ninety percent basal kill as a function of fire size and vegetation and topographic features. The result is a library of simulated high resolution maps of BA90 burned areas for a range of climate and fuels management scenarios with which we estimated conditional probabilities of owl nesting sites being impacted by high severity wildfire.

  7. Rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada

    Science.gov (United States)

    Rood, Dylan H.; Burbank, Douglas W.; Herman, Scott W.; Bogue, Scott

    2011-10-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotations across the central Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. Samples from the Upper Miocene (˜9 Ma) Eureka Valley Tuff suggest clockwise vertical-axis block rotations between NE-striking left-lateral faults in the Bridgeport and Mono Basins. Results in the Bodie Hills suggest clockwise rotations (R ± ΔR, 95% confidence limits) of 74 ± 8° since Early to Middle Miocene (˜12-20 Ma), 42 ± 11° since Late Miocene (˜8-9 Ma), and 14 ± 10° since Pliocene (˜3 Ma) time with no detectable northward translation. The data are compatible with a relatively steady rotation rate of 5 ± 2° Ma-1 (2σ) since the Middle Miocene over the three examined timescales. The average rotation rates have probably not varied by more than a factor of two over time spans equal to half of the total time interval. Our paleomagnetic data suggest that block rotations in the region of the Mina Deflection began prior to Late Miocene time (˜9 Ma), and perhaps since the Middle Miocene if rotation rates were relatively constant. Block rotation in the Bodie Hills is similar in age and long-term average rate to rotations in the Transverse Ranges of southern California associated with early transtensional dextral shear deformation. We speculate that the age of rotations in the Bodie Hills indicates dextral shear and strain accommodation within the central Walker Lane Belt resulting from coupling of the Pacific and North America plates.

  8. Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA) on Streamflow.

    Science.gov (United States)

    Bart, Ryan R; Tague, Christina L; Moritz, Max A

    2016-01-01

    Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada.

  9. Magnetic susceptibility and relation to initial 87Sr/86Sr for granitoids of the central Sierra Nevada, California

    Science.gov (United States)

    Bateman, P.C.; Dodge, F.C.W.; Kistler, R.W.

    1991-01-01

    Measurement of the magnetic susceptibility of more than 6000 samples of granitic rock from the Mariposa 1?? by 2?? quadrangle, which crosses the central part of the Sierra Nevada batholith between 37?? and 38??N latitude, shows that magnetic susceptibility values are above 10-2 SI units in the east and central parts of the batholith and drop abruptly to less than 10-3 SI units in the western foothills. In a narrow transitional zone, intermediate values (10-3 to 10-2) prevail. Magnetic susceptibility appears to decrease slightly westward within the zones of both high and low values. Magnetic susceptibility in plutonic rocks is chiefly a function of the abundance of magnetite, which depends, in turn, on the total iron content of the rocks and their oxidation ratio. Correlations of magnetic susceptibility with initial 87Sr/86Sr suggest that oxidation ratios have been inherited from the source regions for the magmas from which the rocks crystallized. Reduction of Fe3+ to Fe2+ by organic carbon or other reducing substances may also have affected magnetic susceptibility. -from Authors

  10. Hydroclimatic alteration increases vulnerability of montane meadows in the Sierra Nevada, California

    Science.gov (United States)

    Viers, J. H.; Peek, R.; Purdy, S. E.; Emmons, J. D.; Yarnell, S. M.

    2012-12-01

    Meadow ecosystems of the Sierra Nevada (California, USA) have been maintained by the interplay of biotic and abiotic forces, where hydrological functions bridge aquatic and terrestrial realms. Meadows are not only key habitat for fishes, amphibians, birds, and mammals alike, but also provide enumerable ecosystem services to humans, not limited to regulating services (eg, water filtration), provisioning services (eg, grazing), and aesthetics. Using hydroclimatic models and spatial distribution models of indicator species, a range wide assessment was conducted to assess and synthesize the vulnerability of meadow ecosystems to hydroclimatic alteration, a result of regional climate change. Atmospheric warming is expected to result in a greater fraction of total precipitation falling as winter rain (rather than snow) and earlier snowmelt. These predicted changes will likely cause more precipitation-driven runoff in winter and reduced snowmelt runoff in spring, leading to reduced annual runoff and a general shift in runoff timing to earlier in the year. These profound effects have consequences for hydrological cycling and meadow functioning, though such changes will not occur steadily through time or uniformly across the range, and each individual meadow will respond as a function of its composition and land use history. Most vulnerable is groundwater recharge, a fundamental component of meadow hydrology. As a result of shortened snow melt period and absence of diel snowmelt fluxes that would otherwise gradually refill meadow aquifers, recharge is expected to decline due to less infiltration. Diminished water tables will likely stress hydric and mesic vegetation, promoting more xeric conditions. Coupled with greater magnitude stream flows, these conditions promote channel incision and ultimate state shift to non-meadow conditions. The biological effects of hydroclimatic alteration, such as lower mean annual flow and earlier timing, will result in an overall decrease in

  11. Mediterranean climate effects. II. Conifer growth phenology across a Sierra Nevada ecotone.

    Science.gov (United States)

    Royce, E B; Barbour, M G

    2001-05-01

    Growth and xylem water potential of the lower elevation conifers Pinus jeffreyi and Abies concolor and the higher elevation Pinus monticola and Abies magnifica were monitored in their montane Mediterranean habitat of the southernmost Sierra Nevada mountains of California. Measurements were made across the ecotone between the midmontane and upper montane forests and through light and heavy snowfall years.Radial stem growth, averaging ∼1.5 mm/yr, started 2 wk after snow melt, providing that maximum air temperatures had reached 21°C, and ended when predawn water potentials fell rapidly at the onset of the summer drought. Leader growth started on or after a fixed date, providing that minimum air temperatures were above -4°C for Pinus species or +2.5°C for Abies species. The cue for leader growth was inferred to be photoperiodic. Leader growth ended when either a determinate internode length of ∼1 mm was reached or predawn water potentials fell rapidly. Abies magnifica grew more rapidly than the low-elevation species, but had a shorter growth period; its annual leader growth, as a consequence, was only 35 mm/yr vs. 50 mm/yr for the low-elevation species. Needle growth was similarly determinate in the absence of early drought. This growth phenology contributes to determining species distribution across the ecotone.

  12. Long Valley caldera and the UCERF depiction of Sierra Nevada range-front faults

    Science.gov (United States)

    Hill, David P.; Montgomery-Brown, Emily K.

    2015-01-01

    Long Valley caldera lies within a left-stepping offset in the north-northwest-striking Sierra Nevada range-front normal faults with the Hilton Creek fault to the south and Hartley Springs fault to the north. Both Uniform California Earthquake Rupture Forecast (UCERF) 2 and its update, UCERF3, depict slip on these major range-front normal faults as extending well into the caldera, with significant normal slip on overlapping, subparallel segments separated by ∼10  km. This depiction is countered by (1) geologic evidence that normal faulting within the caldera consists of a series of graben structures associated with postcaldera magmatism (intrusion and tumescence) and not systematic down-to-the-east displacements consistent with distributed range-front faulting and (2) the lack of kinematic evidence for an evolving, postcaldera relay ramp structure between overlapping strands of the two range-front normal faults. The modifications to the UCERF depiction described here reduce the predicted shaking intensity within the caldera, and they are in accord with the tectonic influence that underlapped offset range-front faults have on seismicity patterns within the caldera associated with ongoing volcanic unrest.

  13. [Dung beetles (Coleoptera: Scarabaeinae) of the northwestern slope of the Sierra Nevada of Santa Marta, Colombia].

    Science.gov (United States)

    Martínez, Neis J; García, Héctor; Pulido, Luz A; Ospino, Deibi; Harváez, Juan C

    2009-01-01

    The community structure of dung beetles in the middle and lower river basin of the Gaira river, Sierra Nevada de Santa Marta, Colombia, is described. Four sites were selected along an altitudinal gradient of 50-940 m for sampling from June to October, 2004. Dung beetles were captured using modified pitfall traps and manual recollections. We captured 7,872 individuals belonging to 29 species, distributed in 15 genera and five tribes of Scarabaeinae. Canthon and Onthophagus were the most diverse genera, each represented by six species. The sampled sites shared the following species: Onthophagus acuminatus Harold, O. clypeatus Blanchard, O. marginicollis Harold. Bocatoma was the most diverse site with 23 species; whereas Port Mosquito presented the highest abundance, with 3,262 individuals. Seven species represented 89% of all captures: Canthidium sp., Dichotomius sp., Uroxys sp. 1, Uroxys sp. 2, O. marginicollis, O. clypeatus and O. acuminatus. Of the 29 captured species, 17 belonged to the functional group of diggers and 10 were ball-rollers. We did not observe significant among-site differences in community structure. Abiotic factors such as altitude, temperature and humidity cannot explain observed variation in community structure across sites, indicating other variables such as vegetation cover, density of the vegetation and soil type may play a role in the community structure of these insects.

  14. Air Pollution and Watershed Research in the Central Sierra Nevada of California: Nitrogen and Ozone

    Directory of Open Access Journals (Sweden)

    Carolyn Hunsaker

    2007-01-01

    Full Text Available Maintaining healthy forests is the major objective for the Forest Service scientists and managers working for the U.S. Department of Agriculture. Air pollution, specifically ozone (O3 and nitrogenous (N air pollutants, may severely affect the health of forest ecosystems in the western U.S. Thus, the monitoring of air pollution concentration and deposition levels, as well as studies focused on understanding effects mechanisms, are essential for evaluation of risks associated with their presence. Such information is essential for development of proper management strategies for maintaining clean air, clean water, and healthy ecosystems on land managed by the Forest Service. We report on two years of research in the central Sierra Nevada of California, a semi-arid forest at elevations of 1100–2700 m. Information on O3 and N air pollutants is obtained from a network of 18 passive samplers. We relate the atmospheric N concentration to N concentrations in streams, shallow soil water, and bulk deposition collectors within the Kings River Experimental Watershed. This watershed also contains an intensive site that is part of a recent Forest Service effort to calculate critical loads for N, sulfur, and acidity to forest ecosystems. The passive sampler design allows for extensive spatial measurements while the watershed experiment provides intensive spatial data for future analysis of ecosystem processes.

  15. Characterizing the Networks of Digital Information that Support Collaborative Adaptive Forest Management in Sierra Nevada Forests

    Science.gov (United States)

    Lei, Shufei; Iles, Alastair; Kelly, Maggi

    2015-07-01

    Some of the factors that can contribute to the success of collaborative adaptive management—such as social learning, open communication, and trust—are built upon a foundation of the open exchange of information about science and management between participants and the public. Despite the importance of information transparency, the use and flow of information in collaborative adaptive management has not been characterized in detail in the literature, and currently there exist opportunities to develop strategies for increasing the exchange of information, as well as to track information flow in such contexts. As digital information channels and networks have been increased over the last decade, powerful new information monitoring tools have also been evolved allowing for the complete characterization of information products through their production, transport, use, and monitoring. This study uses these tools to investigate the use of various science and management information products in a case study—the Sierra Nevada Adaptive Management Project—using a mixed method (citation analysis, web analytics, and content analysis) research approach borrowed from the information processing and management field. The results from our case study show that information technologies greatly facilitate the flow and use of digital information, leading to multiparty collaborations such as knowledge transfer and public participation in science research. We conclude with recommendations for expanding information exchange in collaborative adaptive management by taking advantage of available information technologies and networks.

  16. Leaf Area Prediction Using Three Alternative Sampling Methods for Seven Sierra Nevada Conifer Species

    Directory of Open Access Journals (Sweden)

    Dryw A. Jones

    2015-07-01

    Full Text Available Prediction of projected tree leaf area using allometric relationships with sapwood cross-sectional area is common in tree- and stand-level production studies. Measuring sapwood is difficult and often requires destructive sampling. This study tested multiple leaf area prediction models across seven diverse conifer species in the Sierra Nevada of California. The best-fit whole tree leaf area prediction model for overall simplicity, accuracy, and utility for all seven species was a nonlinear model with basal area as the primary covariate. A new non-destructive procedure was introduced to extend the branch summation approach to leaf area data collection on trees that cannot be destructively sampled. There were no significant differences between fixed effects assigned to sampling procedures, indicating that data from the tested sampling procedures can be combined for whole tree leaf area modeling purposes. These results indicate that, for the species sampled, accurate leaf area estimates can be obtained through partially-destructive sampling and using common forest inventory data.

  17. Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2014-01-01

    The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) methodology was applied to detected changes in forest vegetation cover for areas burned by wildfires in the Sierra Nevada Mountains of California between the periods of 1975- 79 and 1995-1999. Results for areas burned by wildfire between 1995 and 1999 confirmed the importance of regrowing forest vegetation over 17% of the combined burned areas. A notable fraction (12%) of the entire 5-km (unburned) buffer area outside the 1995-199 fires perimeters showed decline in forest cover, and not nearly as many regrowing forest areas, covering only 3% of all the 1995-1999 buffer areas combined. Areas burned by wildfire between 1975 and 1979 confirmed the importance of disturbed (or declining evergreen) vegetation covering 13% of the combined 1975- 1979 burned areas. Based on comparison of these results to ground-based survey data, the LEDAPS methodology should be capable of fulfilling much of the need for consistent, low-cost monitoring of changes due to climate and biological factors in western forest regrowth following stand-replacing disturbances.

  18. Characterizing the Networks of Digital Information that Support Collaborative Adaptive Forest Management in Sierra Nevada Forests.

    Science.gov (United States)

    Lei, Shufei; Iles, Alastair; Kelly, Maggi

    2015-07-01

    Some of the factors that can contribute to the success of collaborative adaptive management--such as social learning, open communication, and trust--are built upon a foundation of the open exchange of information about science and management between participants and the public. Despite the importance of information transparency, the use and flow of information in collaborative adaptive management has not been characterized in detail in the literature, and currently there exist opportunities to develop strategies for increasing the exchange of information, as well as to track information flow in such contexts. As digital information channels and networks have been increased over the last decade, powerful new information monitoring tools have also been evolved allowing for the complete characterization of information products through their production, transport, use, and monitoring. This study uses these tools to investigate the use of various science and management information products in a case study--the Sierra Nevada Adaptive Management Project--using a mixed method (citation analysis, web analytics, and content analysis) research approach borrowed from the information processing and management field. The results from our case study show that information technologies greatly facilitate the flow and use of digital information, leading to multiparty collaborations such as knowledge transfer and public participation in science research. We conclude with recommendations for expanding information exchange in collaborative adaptive management by taking advantage of available information technologies and networks.

  19. Retention and radiative forcing of black carbon in eastern Sierra Nevada snow

    Directory of Open Access Journals (Sweden)

    K. M. Sterle

    2013-02-01

    Full Text Available When contaminated by absorbing particles, such as refractory black carbon (rBC and continental dust, snow's albedo decreases and thus its absorption of solar radiation increases, thereby hastening snowmelt. For this reason, an understanding of rBC's affect on snow albedo, melt processes, and radiation balance is critical for water management, especially in a changing climate. Measurements of rBC in a sequence of snow pits and surface snow samples in the eastern Sierra Nevada of California during the snow accumulation and ablation seasons of 2009 show that concentrations of rBC were enhanced sevenfold in surface snow (~25 ng g–1 compared to bulk values in the snowpack (~3 ng g–1. Unlike major ions, which were preferentially released during the initial melt, rBC and continental dust were retained in the snow, enhancing concentrations well into late spring, until a final flush occurred during the ablation period. We estimate a combined rBC and continental dust surface radiative forcing of 20 to 40 W m−2 during April and May, with dust likely contributing a greater share of the forcing.

  20. Evaluating potential overlap between pack stock and Sierra Nevada bighorn sheep (Ovis canadensis sierrae) in Sequoia and Kings Canyon National Parks, California

    Science.gov (United States)

    Klinger, Robert C.; Few, Alexandra P.; Knox, Kathleen A.; Hatfield, Brian E.; Clark, Jonathan; German, David W.; Stephenson, Thomas R.

    2015-01-01

    Pack stock (horses, mules, burros, llamas, and goats) are frequently assumed to have negative effects on public lands, but there is a general lack of data to be able to quantify the degree to which this is actually the case. Sequoia and Kings Canyon National Parks have received complaints that pack stock may affect Sierra Nevada bighorn sheep (Ovis canadensis sierrae; SNBS), a federally endangered subspecies that occurs in largely disjunct herds in the Sierra Nevada Range of California. The potential effects are thought to be displacement of SNBS from meadows on their summer range (altered habitat use) or, more indirectly, through changes in SNBS habitat or forage quality. Our goals were to conduct an association analysis to quantify the degree of potential spatial overlap in meadow use between SNBS and pack stock and to compare differences in vegetation community composition, structure, and diversity among meadows with different levels of use by bighorn sheep and pack stock. For the association analysis, we used two approaches: (1) we quantified the proportion of meadows that were within the herd home ranges of bighorn sheep and were potentially open to pack stock, and, (2) we used Monte Carlo simulations and use-availability analyses to compare the proportion of meadows used by bighorn sheep relative to the proportional occurrence or area of meadows available to bighorn sheep that were used by pack stock. To evaluate potential effects of pack stock on meadow plant communities and SNBS forage, we sampled vegetation in 2011 and 2012 at 100 plots to generate data that allowed us to compare:

  1. Next Generation Snow Cover Mapping: Can Future Hyperspectral Satellite Spectrometer Systems Improve Subpixel Snow-covered Area and Grain Size in the Sierra Nevada?

    Science.gov (United States)

    Hill, R.; Calvin, W. M.; Harpold, A.

    2017-12-01

    Mountain snow storage is the dominant source of water for humans and ecosystems in western North America. Consequently, the spatial distribution of snow-covered area is fundamental to both hydrological, ecological, and climate models. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were collected along the entire Sierra Nevada mountain range extending from north of Lake Tahoe to south of Mt. Whitney during the 2015 and 2016 snow-covered season. The AVIRIS dataset used in this experiment consists of 224 contiguous spectral channels with wavelengths ranging 400-2500 nanometers at a 15-meter spatial pixel size. Data from the Sierras were acquired on four days: 2/24/15 during a very low snow year, 3/24/16 near maximum snow accumulation, and 5/12/16 and 5/18/16 during snow ablation and snow loss. Building on previous retrieval of subpixel snow-covered area algorithms that take into account varying grain size we present a model that analyzes multiple endmembers of varying snow grain size, vegetation, rock, and soil in segmented regions along the Sierra Nevada to determine snow-cover spatial extent, snow sub-pixel fraction, and approximate grain size. In addition, varying simulated models of the data will compare and contrast the retrieval of current snow products such as MODIS Snow-Covered Area and Grain Size (MODSCAG) and the Airborne Space Observatory (ASO). Specifically, does lower spatial resolution (MODIS), broader resolution bandwidth (MODIS), and limited spectral resolution (ASO) affect snow-cover area and grain size approximations? The implications of our findings will help refine snow mapping products for planned hyperspectral satellite spectrometer systems such as EnMAP (slated to launch in 2019), HISUI (planned for inclusion on the International Space Station in 2018), and HyspIRI (currently under consideration).

  2. Evolution of the persistence of snow over Sierra Nevada Mountain (southern, Spain) in the last 55 years

    Science.gov (United States)

    Pimentel, Rafael; José Pérez-Palazón, María; Herrero, Javier; José Polo, María

    2016-04-01

    Snow plays a crucial role in mountainous areas, not only as water resources for human supply, irrigation and energy production, but also for the ecosystem, flora and fauna, over these areas. Sierra Nevada Mountains, southern Spain, constitutes a rich reservoir of endemic wildlife species, and it is considered the most important center of biodiversity in the wester Mediterranean region. The highest regions of the range were declared UNESCO Biosphere Reserve, Natural and National Parks. Climate trends over the last decades put a lot of pressure on both snowfall occurrence and snow persistence; this poses a risk for biodiversity and has led to its inclusion in the Global Change Observatory Network. This work quantifies the evolution of the persistence of snow over the Sierra Nevada area during the last fifty-five years (1960-2015) as a basis to assess the vulnerability of its ecosystem services. For this, the spatial distribution of the annual number of days with snow, SDS, was analyzed over a study area of 4583 km2 (140-3479 m.a.s.l.), which comprises the head of the five basins in these mountains. The following indicator variables were studied over the whole area and each one of the five head regions identified: 1) the trend of SDS; 2) the annual area where SDS exceeded selected percentiles in its distribution; and 3) the annual minimum altitude where SDS exceeded those percentiles. SDS was obtained during the study period by means of the snow module in WiMMed (Watershed Integrated Model in Mediterranean Environment), a physically-based hydrological model developed, calibrated and validated in the area; the model is based on an energy-mass balance over the snowpack that is spatially distributed through the use of depletion curves, and is operational at hourly and daily scales. A general decreasing trend of SDS (0.25 days year-1) was found over the whole study area for the study period. This value is higher in the more humid basins (0.45 and 0.41 days year-1) than in

  3. Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA on Streamflow.

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    Ryan R Bart

    Full Text Available Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation < 800 mm, with most streamflow change observed during wetter years. These modeling results underscore the importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada.

  4. Effect of Tree-to-Shrub Type Conversion in Lower Montane Forests of the Sierra Nevada (USA) on Streamflow

    Science.gov (United States)

    Tague, Christina L.; Moritz, Max A.

    2016-01-01

    Higher global temperatures and increased levels of disturbance are contributing to greater tree mortality in many forest ecosystems. These same drivers can also limit forest regeneration, leading to vegetation type conversion. For the Sierra Nevada of California, little is known about how type conversion may affect streamflow, a critical source of water supply for urban, agriculture and environmental purposes. In this paper, we examined the effects of tree-to-shrub type conversion, in combination with climate change, on streamflow in two lower montane forest watersheds in the Sierra Nevada. A spatially distributed ecohydrologic model was used to simulate changes in streamflow, evaporation, and transpiration following type conversion, with an explicit focus on the role of vegetation size and aspect. Model results indicated that streamflow may show negligible change or small decreases following type conversion when the difference between tree and shrub leaf areas is small, partly due to the higher stomatal conductivity and the deep rooting depth of shrubs. In contrast, streamflow may increase when post-conversion shrubs have a small leaf area relative to trees. Model estimates also suggested that vegetation change could have a greater impact on streamflow magnitude than the direct hydrologic impacts of increased temperatures. Temperature increases, however, may have a greater impact on streamflow timing. Tree-to-shrub type conversion increased streamflow only marginally during dry years (annual precipitation < 800 mm), with most streamflow change observed during wetter years. These modeling results underscore the importance of accounting for changes in vegetation communities to accurately characterize future hydrologic regimes for the Sierra Nevada. PMID:27575592

  5. Cryptic elevational zonation in trapdoor spiders (Araneae, Antrodiaetidae, Aliatypus janus complex) from the California southern Sierra Nevada.

    Science.gov (United States)

    Starrett, James; Hayashi, Cheryl Y; Derkarabetian, Shahan; Hedin, Marshal

    2018-01-01

    The relative roles of ecological niche conservatism versus niche divergence in promoting montane speciation remains an important topic in biogeography. Here, our aim was to test whether lineage diversification in a species complex of trapdoor spiders corresponds with riverine barriers or with an ecological gradient associated with elevational tiering. Aliatypus janus was sampled from throughout its range, with emphasis on populations in the southern Sierra Nevada Mountains of California. We collected multi-locus genetic data to generate a species tree for A. janus and its close relatives. Coalescent based hypothesis tests were conducted to determine if genetic breaks within A. janus conform to riverine barriers. Ecological niche models (ENM) under current and Last Glacial Maximum (LGM) conditions were generated and hypothesis tests of niche conservatism and divergence were performed. Coalescent analyses reveal deeply divergent genetic lineages within A. janus, likely corresponding to cryptic species. Two primary lineages meet along an elevational gradient on the western slopes of the southern Sierra Nevada Mountains. ENMs under both current and LGM conditions indicate that these groups occupy largely non-overlapping niches. ENM hypothesis testing rejected niche identity between the two groups, and supported a sharp ecological gradient occurring where the groups meet. However, the niche similarity test indicated that the two groups may not inhabit different background niches. The Sierra Nevada Mountains provide a natural laboratory for simultaneously testing ecological niche divergence and conservatism and their role in speciation across a diverse range of taxa. Aliatypus janus represents a species complex with cryptic lineages that may have diverged due to parapatric speciation along an ecological gradient, or been maintained by the evolution of ecological niche differences following allopatric speciation. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Estado poblacional del orden Plecoptera (Insecta en el Parque Nacional Sierra Nevada en Venezuela y sus implicaciones para planes de conservación

    Directory of Open Access Journals (Sweden)

    Maribet Gamboa

    2010-12-01

    Full Text Available La distribución longitudinal de las especies de plecópteros fue examinada a lo largo del Parque Nacional Sierra Nevada en la región Andina del estado Mérida, Venezuela. El PNSN es uno de las más grandes regiones protegidas y abarca dos subcuencas hidrográficas importantes. Muestras cuantitativas fueron recolectadas en 7 ríos tributarios de estas cuencas a lo largo del PNSN desde febrero a mayo del 2009, con un total de 135 individuos de 4 especies del género Anacroneuria. Sólo en tres ríos (Nuestra Señora, La Picón y Corcovada se encontró la presencia de plecópteros, los análisis de componentes principales muestran que la caracterización del hábitat, la velocidad de la corriente, el oxígeno disuelto y la ausencia de fuentes de perturbación antrópica influyen en un hábitat idóneo para las poblaciones. Los plecópteros se hallan en peligro de desaparición o incluso se han llegado a extinguir en gran parte de su área de distribución como consecuencia de actividades humanas. Planes de conservación deben ser implementados con urgencia, como evitar zonas recreacionales y/o económicas en las cercanías de los mismos.Population status of insects of Plecoptera order in Sierra Nevada National Park in Venezuela and its implications for conservation planning. Longitudinal distribution of Plecoptera species were examined along the Sierra Nevada National Park in the Andean region of Merida State, Venezuela. PNSN is one of the largest protected areas and consists of two major sub-basins. Quantitative samples were collected in 7 river tributaries along the PNSN from February to May of 2009, and a total of 135 individuals and 4 species of the genus Anacroneuria were collected. Only three rivers (Nuestra Señora, La Picón y Corcovada found the presence of stoneflies, the principal component analysis show that the characterization of habitat, current velocity, dissolved oxygen and the absence of human disturbance sources of influence in

  7. Using ecological forecasting of future vegetation transition and fire frequency change in the Sierra Nevada to assess fire management strategies

    Science.gov (United States)

    Thorne, J. H.; Schwartz, M. W.; Holguin, A. J.; Moritz, M.; Batllori, E.; Folger, K.; Nydick, K.

    2013-12-01

    Ecological systems may respond in complex manners as climate change progresses. Among the responses, site-level climate conditions may cause a shift in vegetation due to the physiological tolerances of plant species, and the fire return interval may change. Natural resource managers challenged with maintaining ecosystem health need a way to forecast how these processes may affect every location, in order to determine appropriate management actions and prioritize locations for interventions. We integrated climate change-driven vegetation type transitions with projected change in fire frequency for 45,203 km2 of the southern Sierra Nevada, California, containing over 10 land management agencies as well as private lands. This Magnitude of Change (MOC) approach involves classing vegetation types in current time according to their climate envelopes, and identifying which sites will in the future have climates beyond what that vegetation currently occurs in. Independently, fire models are used to determine the change in fire frequency for each site. We examined 82 vegetation types with >50 grid cell occurrences. We found iconic resources such as the giant sequoia, lower slope oak woodlands, and high elevation conifer forests are projected as highly vulnerable by models that project a warmer drier future, but not as much by models that project a warmer future that is not drier than current conditions. Further, there were strongly divergent vulnerabilities of these forest types across land ownership (National Parks versus US Forest Service lands), and by GCM. For example, of 50 giant sequoia (Sequoiadendron giganteum) groves and complexes, all but 3 (on Sierra National Forest) were in the 2 highest levels of risk of climate and fire under the GFDL A2 projection, while 15 groves with low-to-moderate risk were found on both the National Parks and National Forests 18 in the 2 under PCM A2. Landscape projections of potential MOC suggest that the region is likely to experience

  8. Effects of Varying Cloud Cover on Springtime Runoff in California's Sierra Nevada

    Science.gov (United States)

    Sumargo, E.; Cayan, D. R.

    2017-12-01

    This study investigates how cloud cover modifies snowmelt-runoff processes in Sierra Nevada watersheds during dry and wet periods. We use two of the California Department of Water Resources' (DWR's) quasi-operational models of the Tuolumne and Merced River basins developed from the USGS Precipitation-Runoff Modeling System (PRMS) hydrologic modeling system. Model simulations are conducted after a validated optimization of model performance in simulating recent (1996-2014) historical variability in the Tuolumne and Merced basins using solar radiation (Qsi) derived from Geostationary Operational Environmental Satellite (GOES) remote sensing. Specifically, the questions we address are: 1) how sensitive are snowmelt and runoff in the Tuolumne and Merced River basins to Qsi variability associated with cloud cover variations?, and 2) does this sensitivity change in dry vs. wet years? To address these question, we conduct two experiments, where: E1) theoretical clear-sky Qsi is used as an input to PRMS, and E2) the annual harmonic cycle of Qsi is used as an input to PRMS. The resulting hydrographs from these experiments exhibit changes in peak streamflow timing by several days to a few weeks and smaller streamflow variability when compared to the actual flows and the original simulations. For E1, despite some variations, this pattern persists when the result is evaluated for dry-year and wet-year subsets, reflecting the consistently higher Qsi input available. For E2, the hydrograph shows a later spring-summer streamflow peak in the dry-year subset when compared to the original simulations, indicating the relative importance of the modulating effect of cloud cover on snowmelt-runoff in drier years.

  9. Sensitivities of dry season runoff to precipitation and temperature in southern Sierra Nevada streams

    Science.gov (United States)

    Safeeq, M.; Hunsaker, C. T.; Bales, R. C.

    2016-12-01

    In a mediterranean climate, dry season runoff sustains water supply and supports aquatic habitat and other ecosystems. Precipitation and temperature directly, by regulating recharge and evapotranspiration (ET), and indirectly, by regulating amount and timing of snowmelt, control the dry season runoff in the Sierra Nevada. Here, we explored relative impacts of precipitation and temperature variability on dry season runoff using path analysis. Specific objectives include: (i) to quantify the direct and indirect impacts of precipitation and temperature on 7-day average minimum flow (Qmin) and (ii) to explore the role of preceding year Qmin on fall season runoff (QF). We used daily runoff, air temperature, precipitation, and snow water equivalent (SWE) over 2004-2015 for the ten catchments in the Kings River Experimental Watersheds. For path analysis model of Qmin, we defined annual precipitation and temperature as exogenous variables and peak SWE, day of snow disappearance, and Qmin as endogenous variables. For QF, we defined current year fall precipitation and preceding year Qmin as exogenous variables and current year QF as an endogenous variable. Path analysis results for Qmin show precipitation as a dominant driver when compared to temperature, peak SWE, and day of snow disappearance. However, in half of the catchments that are mostly located at higher elevations the impact of temperature on Qmin was either comparable or exceeded that of precipitation. This relatively high sensitivity of Qmin to air temperature in high elevation catchments is consistent with the earlier findings of increased ET in proportion to warming. The direct effects of peak SWE and day of snow disappearance on Qmin were limited, and indirect effects of temperature and precipitation via peak SWE and day of snow disappearance were not significant. The preceding year Qmin and fall precipitation showed comparable impacts on QF, indicating that the storage in the preceding year modulates current

  10. Isotopic variation in the Tuolumne Intrusive Suite, central Sierra Nevada, California

    Science.gov (United States)

    Kistler, R.W.; Chappell, B.W.; Peck, D.L.; Bateman, P.C.

    1986-01-01

    Granitoid rocks of the compositionally zoned Late Cretaceous Toulumne Intrusive Suite in the central Sierra Nevada, California, have initial87Sr/86Sr values (Sri) and143Nd/144Nd values (Ndi) that vary from 0.7057 to 0.7067 and from 0.51239 to 0.51211 respectively. The observed variation of both Sri and Ndi and of chemical composition in rocks of the suite cannot be due to crystal fractionation of magma solely under closed system conditons. The largest variation in chemistry, Ndi, and Sri is present in the outer-most equigranular units of the Tuolumne Intrusive Suite. Sri varies positively with SiO2, Na2O, K2O, and Rb concentrations, and negatively with Ndi, Al2O3, Fe2O3, MgO, FeO, CaO, MnO, P2O5, TiO2, and Sr concentrations. This covariation of Sri, Ndi and chemistry can be modeled by a process of simple mixing of basaltic and granitic magmas having weight percent SiO2 of 48.0 and 73.3 respectively. Isotopic characteristic of the mafic magma are Sri=0.7047, Ndi=0.51269 and ??18O=6.0, and of the felsic magma are Sri=0.7068, Ndi=0.51212 and ??18O=8.9. The rocks sampled contain from 50 to 80% of the felsic component. An aplite in the outer equigranular unit of the Tuolumne Intrusive Suite apparently was derived by fractional crystallization of plagioclase and hornblende from magma with granudiorite composition that was a product of mixing of the magmas described above. Siliceous magmas derived from the lower crust, having a maximum of 15 percent mantle-derived mafic component, are represented by the inner prophyritic units of the Tuolumne Intrusive Suite. ?? 1986 Springer-Verlag.

  11. The accuracy of matrix population model projections for coniferous trees in the Sierra Nevada, California

    Science.gov (United States)

    van Mantgem, P.J.; Stephenson, N.L.

    2005-01-01

    1 We assess the use of simple, size-based matrix population models for projecting population trends for six coniferous tree species in the Sierra Nevada, California. We used demographic data from 16 673 trees in 15 permanent plots to create 17 separate time-invariant, density-independent population projection models, and determined differences between trends projected from initial surveys with a 5-year interval and observed data during two subsequent 5-year time steps. 2 We detected departures from the assumptions of the matrix modelling approach in terms of strong growth autocorrelations. We also found evidence of observation errors for measurements of tree growth and, to a more limited degree, recruitment. Loglinear analysis provided evidence of significant temporal variation in demographic rates for only two of the 17 populations. 3 Total population sizes were strongly predicted by model projections, although population dynamics were dominated by carryover from the previous 5-year time step (i.e. there were few cases of recruitment or death). Fractional changes to overall population sizes were less well predicted. Compared with a null model and a simple demographic model lacking size structure, matrix model projections were better able to predict total population sizes, although the differences were not statistically significant. Matrix model projections were also able to predict short-term rates of survival, growth and recruitment. Mortality frequencies were not well predicted. 4 Our results suggest that simple size-structured models can accurately project future short-term changes for some tree populations. However, not all populations were well predicted and these simple models would probably become more inaccurate over longer projection intervals. The predictive ability of these models would also be limited by disturbance or other events that destabilize demographic rates. ?? 2005 British Ecological Society.

  12. Conservation of avian diversity in the Sierra Nevada: moving beyond a single-species management focus

    Science.gov (United States)

    White, Angela M.; Zipkin, Elise F.; Manley, Patricia N.; Schlesinger, Matthew D.

    2013-01-01

    Background: As a result of past practices, many of the dry coniferous forests of the western United States contain dense, even-aged stands with uncharacteristically high levels of litter and downed woody debris. These changes to the forest have received considerable attention as they elevate concerns regarding the outcome of wildland fire. However, attempts to reduce biomass through fuel reduction (i.e., thinning of trees) are often opposed by public interest groups whose objectives include maintaining habitat for species of concern such as the spotted owl, Strix occidentalis, the northern goshawk, Accipiter gentilis, and the Pacific fisher, Martes pennanti. Whether protection of these upper-trophic level species confers adequate conservation of avian forest diversity is unknown. Methodology and Principal Findings: We use a multi-species occurrence model to estimate the habitat associations of 47 avian species detected at 742 sampling locations within an 880-km2 area in the Sierra Nevada. Our approach, which accounts for variations in detectability of species, estimates occurrence probabilities of all species in a community by linking species occurrence models into one hierarchical community model, thus improving inferences on all species, especially those that are rare or observed infrequently. We address how the avian community is influenced by covariates related to canopy cover, tree size and shrub cover while accounting for the impacts of abiotic variables known to affect species distributions. Conclusions and Significance: Environmental parameters estimated through our approach emphasize the importance of within and between stand-level heterogeneity in meeting biodiversity objectives and suggests that many avian species would increase under more open canopy habitat conditions than those favored by umbrella species of high conservation concern. Our results suggest that a more integrated approach that emphasizes maintaining a diversity of habitats across

  13. Hillslope Erosion and Water Quality from the Rim Fire, Sierra Nevada, CA

    Science.gov (United States)

    Kuhn, T. J.; Austin, L. J.; Forrester, H.; DeLong, S. B.; Lever, R.; Roche, J. W.

    2014-12-01

    The Rim Fire in 2013 burned approximately 1036 km2 in the Sierra Nevada (including 312 km2 within Yosemite National Park), generating considerable public concern regarding potential impacts to the Tuolumne River watershed, in terms of water quality and water supply infrastructure serving the City of San Francisco. Land management responses included a multi-million dollar watershed treatment project on USFS lands near Cherry Creek, with similar actions suggested for areas in the Hetch Hetchy and Lake Eleanor watersheds. In response to the concern that the post-burn landscape will negatively impact water quality, we are investigating hydrologic effects and hillslope erosion in two small burned basins (2.2 and 5.2 km2) within the Tuolumne River basin in Yosemite National Park. Within a month after fire containment, sites were equipped with instrumentation to record stream stage, turbidity, and total suspended sediment. We also installed 21 sediment fences that trap all sediment silt sized and larger on moderate (20%) to steep (50%) hillslopes from 100 m2 plots within moderate and high severity burn areas. Accumulated sediment is collected, weighed, and sub-sampled after each storm event, and, analyzed for dry weight, particle size, gravimetric water content, bulk density, pH, color, carbon and nitrogen content from % fine organics, and % coarse organics. As of July 31, 2014, four discrete storm events had been sampled. Data are used to calculate annual sediment yield, and to investigate organic carbon storage, deposition, and transport. We are also collecting repeat terrestrial laser scans to assess topographic change and identify the hillslope processes that contribute to erosion and deposition at plot- and hillslope-scale. These findings provide analogs for possible changes in adjacent burned areas and to inform management decisions in response to future fires and potential impacts to water quality in areas valued by the park, the City of San Francisco and other

  14. Conservation of avian diversity in the Sierra Nevada: moving beyond a single-species management focus.

    Directory of Open Access Journals (Sweden)

    Angela M White

    Full Text Available As a result of past practices, many of the dry coniferous forests of the western United States contain dense, even-aged stands with uncharacteristically high levels of litter and downed woody debris. These changes to the forest have received considerable attention as they elevate concerns regarding the outcome of wildland fire. However, attempts to reduce biomass through fuel reduction (i.e., thinning of trees are often opposed by public interest groups whose objectives include maintaining habitat for species of concern such as the spotted owl, Strix occidentalis, the northern goshawk, Accipiter gentilis, and the Pacific fisher, Martes pennanti. Whether protection of these upper-trophic level species confers adequate conservation of avian forest diversity is unknown.We use a multi-species occurrence model to estimate the habitat associations of 47 avian species detected at 742 sampling locations within an 880-km(2 area in the Sierra Nevada. Our approach, which accounts for variations in detectability of species, estimates occurrence probabilities of all species in a community by linking species occurrence models into one hierarchical community model, thus improving inferences on all species, especially those that are rare or observed infrequently. We address how the avian community is influenced by covariates related to canopy cover, tree size and shrub cover while accounting for the impacts of abiotic variables known to affect species distributions.Environmental parameters estimated through our approach emphasize the importance of within and between stand-level heterogeneity in meeting biodiversity objectives and suggests that many avian species would increase under more open canopy habitat conditions than those favored by umbrella species of high conservation concern. Our results suggest that a more integrated approach that emphasizes maintaining a diversity of habitats across environmental gradients and minimizing urbanization may have a

  15. On the relative contributions of wind vs. animals to seed dispersal of four Sierra Nevada pines.

    Science.gov (United States)

    Vander Wall, Stephen B

    2008-07-01

    Selective pressures that influence the form of seed dispersal syndromes are poorly understood. Morphology of plant propagules is often used to infer the means of dispersal, but morphology can be misleading. Several species of pines, for example, have winged seeds adapted for wind dispersal but owe much of their establishment to scatter-hoarding animals. Here the relative importance of wind vs. animal dispersal is assessed for four species of pines of the eastern Sierra Nevada that have winged seeds but differed in seed size: lodgepole pine (Pinus contorta murrayana, 8 mg); ponderosa pine (Pinus ponderosa ponderosa, 56 mg); Jeffrey pine (Pinus jeffreyi, 160 mg); and sugar pine (Pinus lambertiana, 231 mg). Pre-dispersal seed mortality eliminated much of the ponderosa pine seed crop (66%), but had much less effect on Jeffrey pine (32% of seeds destroyed), lodgepole pine (29%), and sugar pine (7%). When cones opened most filled seeds were dispersed by wind. Animals removed > 99% of wind-dispersed Jeffrey and sugar pine seeds from the ground within 60 days, but animals gathered only 93% of lodgepole pine seeds and 38% of ponderosa pine seeds during the same period. Animals gathered and scatter hoarded radioactively labeled ponderosa, Jeffrey, and sugar pine seeds, making a total of 2103 caches over three years of study. Only three lodgepole pine caches were found. Caches typically contained 1-4 seeds buried 5-20 mm deep, depths suitable for seedling emergence. Although Jeffrey and sugar pine seeds are initially wind dispersed, nearly all seedlings arise from animal caches. Lodgepole pine is almost exclusively wind dispersed, with animals acting as seed predators. Animals treated ponderosa pine in an intermediate fashion. Two-phased dispersal of large, winged pine seeds appears adaptive; initial wind dispersal helps to minimize pre-dispersal seed mortality whereas scatter hoarding by animals places seeds in sites with a higher probability of seedling establishment.

  16. Forest thinning and soil respiration in a ponderosa pine plantation in the Sierra Nevada.

    Science.gov (United States)

    Tang, Jianwu; Qi, Ye; Xu, Ming; Misson, Laurent; Goldstein, Allen H

    2005-01-01

    Soil respiration is controlled by soil temperature, soil water, fine roots, microbial activity, and soil physical and chemical properties. Forest thinning changes soil temperature, soil water content, and root density and activity, and thus changes soil respiration. We measured soil respiration monthly and soil temperature and volumetric soil water continuously in a young ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) plantation in the Sierra Nevada Mountains in California from June 1998 to May 2000 (before a thinning that removed 30% of the biomass), and from May to December 2001 (after thinning). Thinning increased the spatial homogeneity of soil temperature and respiration. We conducted a multivariate analysis with two independent variables of soil temperature and water and a categorical variable representing the thinning event to simulate soil respiration and assess the effect of thinning. Thinning did not change the sensitivity of soil respiration to temperature or to water, but decreased total soil respiration by 13% at a given temperature and water content. This decrease in soil respiration was likely associated with the decrease in root density after thinning. With a model driven by continuous soil temperature and water time series, we estimated that total soil respiration was 948, 949 and 831 g C m(-2) year(-1) in the years 1999, 2000 and 2001, respectively. Although thinning reduced soil respiration at a given temperature and water content, because of natural climate variability and the thinning effect on soil temperature and water, actual cumulative soil respiration showed no clear trend following thinning. We conclude that the effect of forest thinning on soil respiration is the combined result of a decrease in root respiration, an increase in soil organic matter, and changes in soil temperature and water due to both thinning and interannual climate variability.

  17. Effects of copper on species composition of periphyton in a Sierra Nevada, California, stream

    Energy Technology Data Exchange (ETDEWEB)

    Leland, H.V.; Carter, J.L.

    1984-06-01

    Changes in species composition of the periphyton of an oliotrophic, Sierra Nevada stream continuously dosed for 1 year at three concentrations of copper (2.5, 5 and 10..mu..g 1/sup -1/ Cu/sub T/; approximately 12, 25 and 50 ng 1/sup -1/ Cu/sup 2 +/) were determined. The numerically most abundant taxa were Bacillariophyceae (Achnanthes minutissima, Cocconeis placentula, Cymbella microcephala, C. sinuata, Fragilaria construens, F. crotonensis, Navicula spp., Synedra acus and S. rumpens), and the Cyanophyta Lynbya spp., a co-dominant during spring and summer. Population densities of Lyngbya spp. were markedly reduced at all test concentrations of copper. Population densities of the principal Chlorophyta (Spirogyra spp. and Cladophora spp.) and the diatom Amphipleura pellucida were reduced at 5 ..mu..g 1/sup -1/ Cu/sub T/. Of the twenty-two most abundant taxa, sixteen were reduced in abundance by continuous exposure to 10 ..mu..g 1/sup -1/ Cu/sub T/. There was no commensurate reduction in standing crop (total number of individuals of all taxa). Achnanthes minutissima, a co-dominant in the control, was the primary replacement species. Other taxa that were more abundant at 5 ..mu..g 1/sup -1/ Cu/sub T/ than in the control were Ceratoneis arcus, Cocconeis placentula, Navicula spp. and Synedra rumpens. Only A. minutissima and Calothrix spp. were more abundant at l10 ..mu..g 1/sup -1/ than in the control. Three resemblance measures (Canberra metric, Bray-Curtis and Dice) and diversity (Brillouin's) were evaluated for detecting differences in species composition among experimental stream sections. The Canberra metric, an index sensitive to proportional rather than absolute differences, was the most informative of these indices.

  18. Does prescribed fire promote resistance to drought in low elevation forests of the Sierra Nevada, California, USA?

    Science.gov (United States)

    van Mantgem, Phillip J.; Caprio, Anthony C.; Stephenson, Nathan L.; Das, Adrian J.

    2016-01-01

    Prescribed fire is a primary tool used to restore western forests following more than a century of fire exclusion, reducing fire hazard by removing dead and live fuels (small trees and shrubs).  It is commonly assumed that the reduced forest density following prescribed fire also reduces competition for resources among the remaining trees, so that the remaining trees are more resistant (more likely to survive) in the face of additional stressors, such as drought.  Yet this proposition remains largely untested, so that managers do not have the basic information to evaluate whether prescribed fire may help forests adapt to a future of more frequent and severe drought.During the third year of drought, in 2014, we surveyed 9950 trees in 38 burned and 18 unburned mixed conifer forest plots at low elevation (accounting for differences in individual tree diameter, common conifer species found in the burned plots had significantly reduced probability of mortality compared to unburned plots during the drought.  Stand density (stems ha-1) was significantly lower in burned versus unburned sites, supporting the idea that reduced competition may be responsible for the differential drought mortality response.  At the time of writing, we are not sure if burned stands will maintain lower tree mortality probabilities in the face of the continued, severe drought of 2015.  Future work should aim to better identify drought response mechanisms and how these may vary across other forest types and regions, particularly in other areas experiencing severe drought in the Sierra Nevada and on the Colorado Plateau.

  19. Sierra Nevada, California, U.S.A., Snow Algae: Snow albedo changes, algal-bacterial interrelationships and ultraviolet radiation effects

    International Nuclear Information System (INIS)

    Thomas, W.H.; Duval, B.

    1995-01-01

    In the Tioga Pass area (upper LeeVining Creek watershed) of the Sierra Nevada (California), snow algae were prevalent in the early summers of 1993 and 1994. Significant negative correlations were found between snow water content. However, red snow caused by algal blooms did not decrease mean albedos in representative snowfields. This was due to algal patchiness; mean albedos would not decrease over the whole water catchment basin; and water supplies would not be affected by the presence of algae. Albedo was also reduced by dirt on the snow, and wind-blown dirt may provide a source of allochthonous organic matter for snow bacteria. However, several observations emphasize the importance of an autochthonous source for bacterial nutrition. Bacterial abundances and production rates were higher in red snow containing algae than in noncolored snow. Bacterial production was about two orders-of-magnitude lower than photosynthetic algal production. Bacteria were also sometimes attached to algal cells. In experiments where snow algae were contained in UV-transmitting quartz tubes, ultraviolet radiation inhibited red snow (collected form open, sunlit areas) photosynthesis about 25%, while green snow (collected from forested, shady locations) photosynthesis was inhibited by 85%. Methanol extracts of red snow algae had greater absorbances in blue and UV spectral regions than did algae from green snow. These differences in UV responses and spectra may be due to habitat (sun vs shade) differences, or may be genetic, since different species were found in the two snow types. However, both habitat and genetic mechanisms may be operating together to cause these differences. 53 refs., 5 figs., 5 tabs

  20. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Cisneros, Ricardo, E-mail: rcisneros@fs.fed.u [USDA Forest Service, Pacific Southwest Region, 1600 Tollhouse Road, Clovis, CA 93611 (United States); Bytnerowicz, Andrzej, E-mail: abytnerowicz@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Dr., Riverside, CA 92507 (United States); Schweizer, Donald, E-mail: dschweizer@fs.fed.u [USDA Forest Service, Pacific Southwest Region, 1600 Tollhouse Road, Clovis, CA 93611 (United States); Zhong, Sharon, E-mail: zhongs@msu.ed [Department of Geography, Michigan State University, 116 Geography Building East, Lansing, MI 48824-1117 (United States); Traina, Samuel, E-mail: straina@ucmerced.ed [Environmental Systems Graduate Group, University of California Merced, 5200 North Lake Road, Merced, CA 95343 (United States); Bennett, Deborah H., E-mail: dhbennett@ucdavis.ed [Department of Public Health Sciences, University of California Davis, One Shields Avenue, TB 169 Davis, CA 95616 (United States)

    2010-10-15

    Two-week average concentrations of ozone (O{sub 3}), nitric acid vapor (HNO{sub 3}) and ammonia (NH{sub 3}) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O{sub 3}, 1.0-3.8 {mu}g m{sup -3} for HNO{sub 3}, and 2.6-5.2 {mu}g m{sup -3} for NH{sub 3}. Calculated O{sub 3} exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha{sup -1} for maximum values, and 0.4-8 kg N ha{sup -1} for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O{sub 3} human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O{sub 3}. - Ozone concentrations remained unchanged while those of nitric acid vapor and ammonia decreased along the river drainage crossing the Sierra Nevada Mountains.

  1. Ozone, nitric acid, and ammonia air pollution is unhealthy for people and ecosystems in southern Sierra Nevada, California

    International Nuclear Information System (INIS)

    Cisneros, Ricardo; Bytnerowicz, Andrzej; Schweizer, Donald; Zhong, Sharon; Traina, Samuel; Bennett, Deborah H.

    2010-01-01

    Two-week average concentrations of ozone (O 3 ), nitric acid vapor (HNO 3 ) and ammonia (NH 3 ) were measured with passive samplers during the 2002 summer season across the central Sierra Nevada Mountains, California, along the San Joaquin River drainage. Elevated concentrations of the pollutants were determined with seasonal means for individual sites ranging between 62 and 88 ppb for O 3 , 1.0-3.8 μg m -3 for HNO 3 , and 2.6-5.2 μg m -3 for NH 3 . Calculated O 3 exposure indices were very high, reaching SUM00-191 ppm h, SUM60-151 ppm h, and W126-124 ppm h. Calculated nitrogen (N) dry deposition ranged from 1.4 to 15 kg N ha -1 for maximum values, and 0.4-8 kg N ha -1 for minimum values; potentially exceeding Critical Loads (CL) for nutritional N. The U.S., California, and European 8 h O 3 human health standards were exceeded during 104, 108, and 114 days respectively, indicating high risk to humans from ambient O 3 . - Ozone concentrations remained unchanged while those of nitric acid vapor and ammonia decreased along the river drainage crossing the Sierra Nevada Mountains.

  2. Holocene vegetation and climate change recorded in alpine bog sediments from the Borreguiles de la Virgen, Sierra Nevada, southern Spain

    Science.gov (United States)

    Jiménez-Moreno, Gonzalo; Anderson, R. Scott

    2012-01-01

    High-resolution pollen and magnetic susceptibility (MS) analyses have been carried out on a sediment core taken from a high-elevation alpine bog area located in Sierra Nevada, southern Spain. The earliest part of the record, from 8200 to about 7000 cal yr BP, is characterized by the highest abundance of arboreal pollen and Pediastrum, indicating the warmest and wettest conditions in the area at that time. The pollen record shows a progressive aridification since 7000 cal yr BP that occurred in two steps, first shown by a decrease in Pinus, replaced by Poaceae from 7000 to 4600 cal yr BP and then by Cyperaceae, Artemisia and Amaranthaceae from 4600 to 1200 cal yr BP. Pediastrum also decreased progressively and totally disappeared at ca. 3000 yr ago. The progressive aridification is punctuated by periodically enhanced drought at ca. 6500, 5200 and 4000 cal yr BP that coincide in timing and duration with well-known dry events in the Mediterranean and other areas. Since 1200 cal yr BP, several changes are observed in the vegetation that probably indicate the high-impact of humans in the Sierra Nevada, with pasturing leading to nutrient enrichment and eutrophication of the bog, Pinus reforestation and Olea cultivation at lower elevations.

  3. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

    International Nuclear Information System (INIS)

    Preisler, Haiganoush K.; Zhong Shiyuan; Esperanza, Annie; Brown, Timothy J.; Bytnerowicz, Andrzej; Tarnay, Leland

    2010-01-01

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. - We have demonstrated that it is possible to produce accurate forecasts of next-day hourly ozone levels in the Sierra Nevada, CA, during fire season.

  4. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

    Energy Technology Data Exchange (ETDEWEB)

    Preisler, Haiganoush K., E-mail: hpreisler@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 800 Buchanan St, Albany, CA 94710 (United States); Zhong Shiyuan, E-mail: zhongs@msu.ed [Department of Geography, Michigan State University, 116 Geography Building, East Lansing, MI 48824-1117 (United States); Esperanza, Annie, E-mail: annie_esperanza@nps.go [Sequoia and Kings Canyon National Parks, 47050 Generals Highway Three Rivers, CA 93271 (United States); Brown, Timothy J., E-mail: tim.brown@dri.ed [Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89521-10095 (United States); Bytnerowicz, Andrzej, E-mail: abytnerowicz@fs.fed.u [USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507 (United States); Tarnay, Leland, E-mail: Leland_Tarnay@nps.go [Yosemite National Park, El Portal, CA 95318 (United States)

    2010-03-15

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. - We have demonstrated that it is possible to produce accurate forecasts of next-day hourly ozone levels in the Sierra Nevada, CA, during fire season.

  5. Groundwater-quality data for the Sierra Nevada study unit, 2008: Results from the California GAMA program

    Science.gov (United States)

    Shelton, Jennifer L.; Fram, Miranda S.; Munday, Cathy M.; Belitz, Kenneth

    2010-01-01

    Groundwater quality in the approximately 25,500-square-mile Sierra Nevada study unit was investigated in June through October 2008, as part of the Priority Basin Project of the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Priority Basin Project is being conducted by the U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB). The Sierra Nevada study was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems in the study unit, and to facilitate statistically consistent comparisons of groundwater quality throughout California. The primary aquifer systems (hereinafter, primary aquifers) are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for public and community drinking-water supplies. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallow groundwater may be more vulnerable to contamination from the surface. In the Sierra Nevada study unit, groundwater samples were collected from 84 wells (and springs) in Lassen, Plumas, Butte, Sierra, Yuba, Nevada, Placer, El Dorado, Amador, Alpine, Calaveras, Tuolumne, Madera, Mariposa, Fresno, Inyo, Tulare, and Kern Counties. The wells were selected on two overlapping networks by using a spatially-distributed, randomized, grid-based approach. The primary grid-well network consisted of 30 wells, one well per grid cell in the study unit, and was designed to provide statistical representation of groundwater quality throughout the entire study unit. The lithologic grid-well network is a secondary grid that consisted of the wells in the primary grid-well network plus 53 additional wells and was designed to provide statistical representation of groundwater quality in each of the four major lithologic units in the Sierra

  6. Short-term effects of fire and forest thinning on truffle abundance and consumption by Neotamias speciosus in the Sierra Nevada of California

    Science.gov (United States)

    Marc D. Meyer; Malcolm P. North; Douglas A. Kelt

    2005-01-01

    In many western North American forests, prescribed burning and mechanical thinning are widely used to reduce fuels and restore stand conditions after a century of fire suppression. Few studies have followed the relative impacts of these treatments on the production and consumption of truffles in forest ecosystems, particularly in the Sierra Nevada of California. Using...

  7. Canopy arthropod responses to thinning and burning treatments in old-growth mixed-conifer forest in the Sierra Nevada, California

    Science.gov (United States)

    Thomas Rambo; Timothy Schowalter; Malcolm North

    2014-01-01

    We compared canopy arthropod responses to common fuels reduction treatments at Teakettle Experimental Forest in the south-central Sierra Nevada of California. We sampled arthropod communities among four dominant overstory conifer species and three dominant understory angiosperm species before and after overstory or understory thinning or no thinning treatments followed...

  8. EFFECTS OF CLIMATE VARIABILITY ON THE CARBON DIOXIDE, WATER, AND SENSIBLE HEAT FLUXES ABOVE A PONDEROSA PINE PLANTATION IN THE SIERRA NEVADA, CA. (R826601)

    Science.gov (United States)

    AbstractFluxes of CO2, water vapor, and sensible heat were measured by the eddy covariance method above a young ponderosa pine plantation in the Sierra Nevada Mountains (CA) over two growing seasons (1 June¯10 September 1997 and 1 May&#...

  9. Studies on Colombian cryptogams XX. A transect analysis of the bryophyte vegetation along an altitudinal gradient on the Sierra Nevada de Santa Marta, Colombia

    NARCIS (Netherlands)

    Reenen, van G.B.A.; Gradstein, S.R.

    1983-01-01

    Along an altitudinal transect on the northern slope of the Sierra Nevada de Santa Marta, Colombia, 500-4100 m, five altitudinal bryophyte zones are distinguished – four forest zones and one páramo zone – based on ecosystem relevé analysis concerning species presence, substrate preference and

  10. Meta-analysis of California Spotted Owl (Strix occidentalis occidentalis) territory occupancy in the Sierra Nevada: habitat associations and their implications for forest management

    Science.gov (United States)

    Douglas J. Tempel; John J. Keane; R. J. Gutierrez; Jared D. Wolfe; Gavin M. Jones; Alexander Koltunov; Carlos M. Ramirez; William J. Berigan; Claire V. Gallagher; Thomas E. Munton; Paula A. Shaklee; Sheila A. Whitmore; M. Zachariah Peery

    2016-01-01

    We assessed the occupancy dynamics of 275 California Spotted Owl (Strix occidentalis occidentalis) territories in 4 study areas in the Sierra Nevada, California, USA, from 1993 to 2011. We used Landsat data to develop maps of canopy cover for each study area, which we then used to quantify annual territory-specific habitat...

  11. Landscape fuel reduction, forest fire, and biophysical linkages to local habitat use and local persistence of fishers (Pekania pennanti) in Sierra Nevada mixed-conifer forests

    Science.gov (United States)

    R.A. Sweitzer; B.J. Furnas; R.H. Barrett; Kathryn Purcell; Craig Thompson

    2016-01-01

    Fire suppression and logging have contributed to major changes in California’s Sierra Nevada forests. Strategically placed landscape treatments (SPLATS) are being used to reduce density of trees, shrubs, and surface fuels to limit wildfire intensity and spread, but may negatively impact fishers (Pekania pennanti). We used camera traps to survey for...

  12. Hydrogeologic influence on changes in snowmelt runoff with climate warming: Numerical experiments on a mid-elevation catchment in the Sierra Nevada, USA

    Science.gov (United States)

    S.M. Jepsen; T.C. Harmon; M.W. Meadows; C.T. Hunsaker

    2016-01-01

    The role of hydrogeology in mediating long-term changes in mountain streamflow, resulting from reduced snowfall in a potentially warmer climate, is currently not well understood. We explore this by simulating changes in stream discharge and evapotranspiration from a mid-elevation, 1-km2 catchment in the southern Sierra Nevada of California (USA)...

  13. Critical Loads of Acid Deposition for Wilderness Lakes in the Sierra Nevada (California) Estimated by the Steady-State Water Chemistry Model

    Science.gov (United States)

    Glenn D. Shaw; Ricardo Cisneros; Donald Schweizer; James O. Sickman; Mark E. Fenn

    2014-01-01

    Major ion chemistry (2000-2009) from 208 lakes (342 sample dates and 600 samples) in class I and II wilderness areas of the Sierra Nevada was used in the Steady-State Water Chemistry (SSWC) model to estimate critical loads for acid deposition and investigate the current vulnerability of high elevation lakes to acid deposition. The majority of the lakes were dilute (...

  14. Potential climatic refugia in semi-arid, temperate mountains: plant and arthropod assemblages associated with rock glaciers, talus slopes, and their forefield wetlands, Sierra Nevada, California, USA

    Science.gov (United States)

    Constance I. Millar; Robert D. Westfall; Angela Evenden; Jeffrey G. Holmquist; Jutta Schmidt-Gengenbach; Rebecca S. Franklin; Jan Nachlinger; Diane L. Delany

    2015-01-01

    Unique thermal and hydrologic regimes of rock-glacier and periglacial talus environments support little-studied mountain ecosystems. We report the first studies of vascular plant and arthropod diversity for these habitats in the central Sierra Nevada, California, USA. Surfaces of active rock glaciers develop scattered islands of soil that provide habitat for vegetation...

  15. Inexistence of permafrost at the top of the Veleta peak (Sierra Nevada)

    Science.gov (United States)

    Gómez-Ortiz, Antonio; Salvador-Franch, Ferran; Salvà-Catarineu, Montserrat; Oliva, Marc; Palacios, David; Tanarro, Luis Miguel; Schulte, Lothar

    2014-05-01

    Several deep drillings wew carried out along a latitudinal transect from Svalbard (78°N) to Sierra Nevada (37°N, Spain) within the project Permafrost and Climate Change in Europe (PACE). In this abstract we discuss the data corresponding to the drilling existing at the top of the Veleta peak, at an altitude of 3380 m. This drilling reach a depth of 114.5 m depth, although we analyze here the data of the first 60 m depth. UTL-1 loggers were installed at depths of 0.2, 0.6, 1.2, 2.6, 4, 7, 10, 13, 15, 20 and 60 m. The observation period spans from 2002 to 2013 with data being taken every 2 h. The most surficial loggersrecorded the largest annual temperature oscillations, reaching 22.6°C at 20 cm. Down to 10 m depth the annual temperature amplitude is still remarkable and seasonal temperature changes are even observed at depths of 15 to 20 m. Below this level the temperature remains constant. The logger installed at 60 m depth recorded small temperature changes between 2006 and 2009, oscillating between 2.38 and 2.61ºC. Since January 2010 the temperatures stabilized at 2.61°C. However, this slight temperature increase must be framed within the margin of instrumentation error of the devices. Data shows evidence of the inexistence ofpermanent negative temperatures at depth. In contrast to what happens in the nearby Veleta cirque floor (3100 m), where marginal permafrost conditions have been recorded, in the Veleta peak (3380 m) data points to the absence of a permafrost regime. This may be due to several factors: a) The existence of permafrost in the Veletacirque is directly related to the presence of fossil glacier ice corresponding to a glacier that existed there during the Little Ice Age. b ) The early melting of snow cover in the Veleta peak due to wind effect and incidence of solar radiation condition the absence of permafrost conditions at the summitin contrast to the Veleta cirquefloor, where the longer persistence of snow favours the presence of continuous

  16. Cracking the Stoping Paradigm: Field and Modeling Constraints From the Sierra Nevada Batholith

    Science.gov (United States)

    Pignotta, G. S.; Paterson, S. R.; Okaya, D.

    2001-12-01

    The significance of stoping during pluton emplacement remains a controversial issue. This mechanism has fallen out of favor recently largely due to the apparent lack of stoped blocks preserved in plutons. Our field studies in plutons in a variety of tectonic settings clearly show evidence of stoping. This is not surprising since stoping should be favored when large thermal gradients exist at magma-host rock boundaries. Preservation of stoped blocks is uncommon however, since the rate at which blocks sink is much greater than the rate at which magmas crystallize (Paterson and Okaya, 1999). Thus, only during final crystallization when magmatic yield strength is high, should stoped blocks be trapped. The Mitchell Peak granodiorite, Sierra Nevada is a rare example of a pluton that preserves abundant stoped blocks, with the youngest intrusive phase preserving >25% stoped blocks, and locally, near the margins >50% of exposed surface area is stoped blocks. Thus stoping is an important process here, at least during the final stages of emplacement. This area is ideal to study the mechanisms of block formation and disintegration using both field and modeling techniques, because of abundant stoped blocks, excellent exposure, and nature of host rock. The host rock is a slightly older, coarse grained, granodioritic intrusion that preserves extremely weak to no magmatic fabric, and thus can be treated as a "homogeneous and isotropic" medium for the purposes of thermal-mechanical modeling. Detailed mapping indicates that preserved stoped blocks range in size from hundreds of m's to xenocrystic feldspars, and there is abundant evidence for mechanical disintegration of blocks. Thermal-mechanical models, using detailed maps from the Mitchell Peak area, further support field observations. Rates at which thermal stresses develop and exceed host rock tensile strength are extremely rapid (hours to days) compared to onset of crystal plastic flow and/or melting. The calculated pattern of

  17. Early Neogene unroofing of the Sierra Nevada de Santa Marta along the Bucaramanga -Santa Marta Fault

    Science.gov (United States)

    Piraquive Bermúdez, Alejandro; Pinzón, Edna; Bernet, Matthias; Kammer, Andreas; Von Quadt, Albrecht; Sarmiento, Gustavo

    2016-04-01

    Plate interaction between Caribbean and Nazca plates with Southamerica gave rise to an intricate pattern of tectonic blocks in the Northandean realm. Among these microblocks the Sierra Nevada de Santa Marta (SNSM) represents a fault-bounded triangular massif composed of a representative crustal section of the Northandean margin, in which a Precambrian to Late Paleozoic metamorphic belt is overlain by a Triassic to Jurassic magmatic arc and collateral volcanic suites. Its western border fault belongs to the composite Bucaramanga - Santa Marta fault with a combined left lateral-normal displacement. SE of Santa Marta it exposes remnants of an Oligocene marginal basin, which attests to a first Cenoizoic activation of this crustal-scale lineament. The basin fill consists of a sequence of coarse-grained cobble-pebble conglomerates > 1000 m thick that unconformably overlay the Triassic-Jurassic magmatic arc. Its lower sequence is composed of interbedded siltstones; topwards the sequence becomes dominated by coarser fractions. These sedimentary sequences yields valuable information about exhumation and coeval sedimentation processes that affected the massif's western border since the Upper Eocene. In order to analyse uplifting processes associated with tectonics during early Neogene we performed detrital zircon U-Pb geochronology, detrital thermochronology of zircon and apatites coupled with the description of a stratigraphic section and its facies composition. We compared samples from the Aracataca basin with analog sequences found at an equivalent basin at the Oca Fault at the northern margin of the SNSM. Our results show that sediments of both basins were sourced from Precambrian gneisses, along with Mesozoic acid to intermediate plutons; sedimentation started in the Upper Eocene-Oligocene according to palynomorphs, subsequently in the Upper Oligocene a completion of Jurassic to Cretaceous sources was followed by an increase of Precambrian input that became the dominant

  18. 75 FR 76975 - 2015 Resource Pool-Sierra Nevada Region

    Science.gov (United States)

    2010-12-10

    ... and allocation criteria set forth in the Marketing Plan. Comment: Four commentors requested that, in... Western Area Power Administration (Western), a Federal power marketing administration of DOE, announces the Final 2015 Resource Pool allocations pursuant to its 2004 Power Marketing Plan (Marketing Plan...

  19. Holocene climate variability in the western Mediterranean through a multiproxy analysis from Padul peat bog (Sierra Nevada, Spain)

    Science.gov (United States)

    Ramos-Román, María J.; Jiménez-Moreno, Gonzalo; Camuera, Jon; García-Alix, Antonio; Anderson, R. Scott; Jiménez-Espejo, Francisco J.; Sachse, Dirk

    2017-04-01

    The Iberian Peninsula, located in the Mediterranean area, is an interesting location for paleoclimate studies due to its geographic situation between arid and humid climates. Sediments from peat bogs and lakes from Sierra Nevada, in southeastern Iberian Peninsula, have been very informative in terms of how vegetation and wetland environments were impacted by Holocene climate change. These studies are essential if we want to understand the past climate change in the area, which is the key to identify the possible environmental response of the Sierra Nevada ecosystems to future climate scenarios. Padul basin, located in the southwest of the Sierra Nevada mountain range, contains a ca. 100 m-thick peat bog sedimentary sequence that was deposited during the past 1 Ma making this area interesting for paleoenvironmental and paleoclimatic reconstructions. A new 43 m-long sedimentary record has recently been retrieved from the Padul peat bog. In this study we have developed a multiproxy analysis of the Holocene part of the Padul-15-05 core including pollen analysis, XRF-core scanner, magnetic susceptibility and organic geochemistry, supported by an age control based on AMS radiocarbon dates, providing with information about vegetation and climate variability during the past 9.9 cal ka BP. This multiproxy reconstruction of the Padul-15-05 evidences the Mediterranean as a sensitive area with respect to global-scale climate system, showing relevant climate episodes such as the ca. 8, 7.5, 6.5 and 5.5 cal ka BP events during the early and middle Holocene. The trend to aridification to the late Holocene is interrupted by more arid and humid periods as the Iberian Roman Humid Period (from ca. 3 to 1.6 cal ka BP), the Dark Ages (from ca. 1.5 to 1.1 cal ka BP), the Medieval Climate Anomaly (from ca. 1.1 to 1.3 cal ka BP) and the Little Ice Age period (from ca. 500 to 100 cal yr BP).

  20. Mercury concentrations and pools in four Sierra Nevada forest sites, and relationships to organic carbon and nitrogen

    Directory of Open Access Journals (Sweden)

    D. Obrist

    2009-05-01

    Full Text Available This study presents data on mercury (Hg concentrations, stochiometric relations to carbon (C and nitrogen (N, and Hg pool sizes in four Sierra Nevada forest sites of similar exposure and precipitation regimes, and hence similar atmospheric deposition, to evaluate how ecosystem parameters control Hg retention in ecosystems. In all four sites, the largest amounts of Hg reside in soils which account for 94–98% of ecosystem pools. Hg concentrations and Hg/C ratios increase in the following order: Green Needles/Leavesr2=0.58 and N and C (r2=0.64 in decomposing litter, but a positive correlation between litter Hg and N (r2=0.70. These inverse relations may reflect preferential retention of N and Hg over C during decomposition, or may be due to older age of decomposed litter layers which are exposed to longer-term atmospheric Hg deposition in the field. The results indicate that litter Hg levels depend on decomposition stage and may not follow generally observed positive relationships between Hg and organic C.

    Mineral soil layers show strong positive correlations of Hg to C across all sites and soil horizons (r2=0.83, but Hg concentrations are even more closely related to N with a similar slope to that observed in litter (r2=0.92. Soil N levels alone explain over 90% of Hg pool sizes across the four Sierra Nevada forest sites. This suggests that soil organic N and C groups provide sorption sites for Hg to retain atmospheric deposition. However, the patterns could be due to indirect relationships where high soil N and C levels reflect high ecosystem productivity which leads to corresponding high atmospheric Hg deposition inputs via leaf litterfall and plant senescence. Our results also show that two of the sites previously affected by

  1. Vegetation response to the 2016-2017 extreme Sierra Nevada snowfall event using multitemporal terrestrial laser scanning: initial results

    Science.gov (United States)

    Greenberg, J. A.; Hou, Z.; Ramirez, C.; Hart, R.; Marchi, N.; Parra, A. S.; Gutierrez, B.; Tompkins, R.; Harpold, A.; Sullivan, B. W.; Weisberg, P.

    2017-12-01

    The Sierra Nevada Mountains experienced record-breaking snowfall during the 2016-2017 winter after a prolonged period of drought. We hypothesized that at lower elevations, the increased snowmelt would result in a significant increase in biomass across vegetation strata, but at higher elevations, the snowpack would result in a diminished growing season, and yield a suppression of growth rates particularly in the understory vegetation. To test these hypotheses, we sampled sites across the Plumas National Forest and Lake Tahoe Basin using a terrestrial laser scanner (TLS) in the early growing season, and then rescanned these sites in the late growing season. Herein, we present initial, early results from this analysis, focusing on the biomass and height changes in trees.

  2. Photogrammetric Methodology for the Production of Geomorphologic Maps: Application to the Veleta Rock Glacier (Sierra Nevada, Granada, Spain

    Directory of Open Access Journals (Sweden)

    José Jesús Guerrero

    2009-10-01

    Full Text Available In this paper we present a stereo feature-based method using SIFT (Scale-invariant feature transform descriptors. We use automatic feature extractors, matching algorithms between images and techniques of robust estimation to produce a DTM (Digital Terrain Model using convergent shots of a rock glacier.The geomorphologic structure observed in this study is the Veleta rock glacier (Sierra Nevada, Granada, Spain. This rock glacier is of high scientific interest because it is the southernmost active rock glacier in Europe and it has been analyzed every year since 2001. The research on the Veleta rock glacier is devoted to the study of its displacement and cartography through geodetic and photogrammetric techniques.

  3. An ecologic study comparing distribution of Pasteurella trehalosi and Mannheimia haemolytica between Sierra Nevada bighorn sheep, White Mountain bighorn sheep, and domestic sheep.

    Science.gov (United States)

    Tomassini, Letizia; Gonzales, Ben; Weiser, Glen C; Sischo, William

    2009-10-01

    The prevalence and phenotypic variability of Pasteurella and Mannheimia isolates from Sierra Nevada bighorn sheep (Ovis canadensis sierrae), White Mountain bighorn sheep (Ovis canadensis nelsoni), and domestic sheep (Ovis aries) from California, USA, were compared. The White Mountain bighorn sheep population had a recent history of pneumonia-associated mortality, whereas the Sierra Nevada bighorn sheep population had no recent history of pneumonia-associated mortality. The domestic sheep flocks were pastured in areas geographically near both populations but were not known to have direct contact with either bighorn sheep population. Oropharyngeal swab samples were collected from healthy domestic and bighorn sheep and cultured to characterize bacterial species, hemolysis, biogroups, and biovariants. Pasteurella trehalosi and Mannheimia haemolytica were detected in all of the study populations, but the relative proportion of each bacterial species differed among sheep populations. Pasteurella trehalosi was more common than M. haemolytica in the bighorn sheep populations, whereas the opposite was true in domestic sheep. Mannheimia haemolytica was separated into 11 biogroups, and P. trehalosi was characterized into two biogroups. Biogroup distributions for M. haemolytica and P. trehalosi differed among the three populations; however, no difference was detected for the distribution of P. trehalosi biogroups between the Sierra Nevada bighorn sheep and domestic sheep. The prevalence odds ratios (pOR) for the distribution of M. haemolytica biogroups suggested little difference between White Mountain bighorn sheep and domestic sheep compared with Sierra Nevada bighorn sheep and domestic sheep, although these comparisons had relatively large confidence intervals for the point estimates. Hemolytic activity of the isolates was not different among the sheep populations for M. haemolytica but was different for P. trehalosi. No clear evidence of association was found in the

  4. [Reproduction of Joturus pichardi and Agonostomus monticola (Mugiliformes: Mugilidae) in rivers of the Sierra Nevada de Santa Marta, Colombia].

    Science.gov (United States)

    Eslava Eljaiek, Pedro; Díaz Vesga, Roy

    2011-12-01

    The freshwater mugilids Joturus pichardi and Agonostomus monticola, have been documented on ecological and distribution aspects, mainly for Central American populations, nevertheless, little information is available on their reproductive aspects, specifically in Colombian freshwater environments. Reproductive biology of the mugilids J. pichardi and A. monticola from Sierra Nevada de Santa Marta (SNSM) rivers was studied between July 2005 and December 2006. A total of 14 specimens of J. pichardi and 320 of A. monticola were collected. The reproductive biology was analyzed by means of: sexual proportion, gonadosomatic index, and mean size at maturity, fecundity and oocyte diameter. Additionally, a bioassay was carried out to evaluate the effect of salinity on spermatic motility and its possible relationship with the species' spawning area. These mugilids share habitats with similar ecological characteristics, in which strong currents; clear water and stony areas stand out. Gonadal maturity indicators and indirect evidence are presented to support the relationship between reproductive maturity and higher rainfall levels in the area (September, October and November), as well as the catadromous migration of J. pichardi and A. monticola. This last species females outnumbered males with a sex ratio of 2.3:1. Females mean size at maturity was 172mm of their total length (TL) and 108mm TL for males. Fecundity (F) was 23 925 +/- 4 581 eggs per gram of gonad, and was related to size by the equation F = 395.1TL(1.281); besides, the mean oocyte diameter was 362 +/- 40 microm. Considering the salinity effect on sperm motility in both species, results suggested that J. pichardi spawned in estuarine environments but the species did not migrate to fully marine environments; however, A. monticola withstood a broad range of salinity, suggesting a spawning from intermediate to total saline environments. Both species have high culturing potentials, considering that their feeding is

  5. Occurrence patterns of Black-backed Woodpeckers in green forest of the Sierra Nevada Mountains, California, USA.

    Directory of Open Access Journals (Sweden)

    Alissa M. Fogg

    2014-12-01

    Full Text Available Black-backed Woodpeckers (Picoides arcticus are a rare habitat specialist typically found in moderate and high severity burned forest throughout its range. It also inhabits green forest but little is known about occurrence and habitat use patterns outside of burned areas, especially in the Sierra Nevada of California, USA. We used point count and playback surveys to detect Black-backed Woodpeckers during 2011 - 2013 on 460 transects on 10 national forest units. We defined green forest as areas that had not burned at moderate or high severity since 1991 and were more than 2 km from areas burned at moderate or high severity within the previous eight years (n = 386 transects. We used occupancy models to examine green forest habitat associations and found positive relationships with elevation, latitude, northern aspects, number of snags, tree diameter, lodgepole pine (Pinus contorta forest, and a negative relationship with slope. Estimated occupancy in green forest was higher than previously understood (0.21. In addition site colonization and extinction probability in green forest were low (0.05 and 0.19, respectively and suggest that many of the individuals detected in green forest were not just actively dispersing across the landscape in search of burned areas, but were occupying relatively stable home ranges. The association with high elevation and lodgepole pine forest may increase their exposure to climate change as these elevation forest types are predicted to decrease in extent over the next century. Although density is high in burned forest, green forest covers significantly more area in the Sierra Nevada and should be considered in efforts to conserve this rare species.

  6. Mining districts in the Carson Sink region, Nevada

    Science.gov (United States)

    Schrader, F.

    1947-01-01

    The region lies in an area of primarily sedimentary rocks which are principally Mesozoic and are tilted, folded, and faulted and cut by granular intrusives, and flooded by Tertiary lavas as shown on Figure 4. The Mesozoic sediments were strongly folded and invaded by granular intrusives at or about the time of the intrusion of the great Sierra Nevada batholith. The rocks are exposed chiefly in the mountain ranges and hills.The mountain ranges are mostly fault ranges with much of their structure monoclinical. Faulting in many instances has been prominent since the deposition of the Tertiary lavas and continues down to the present, as shown by fresh scarps and recent earthquake disturbances in the Stillwater and Augusta ranges and in general along the flaks of the various ranges by the tilted attitude of the lava flows and lake beds, and by the older lavas in general being tilted at steeper angles than the overlying lake beds. The faulting may be normal or overthrust.The faulting shown in the various mining districts as Fairview and Wonder may be regarded as indicating that of the region in general.In some parts of the region faulting is so young that it is still shown in the topographic forms as by trunctated gulches in the east base of the Stillwater range in Dixie Valley.As the writer in the present work had but small opportunity to examine the rocks excepting in the various mining districts many of which are located far apart, the accompanying geologic map (Fig. 4) is largely compiled from earlier reports of various authors in order to here present a geologic picture of the region. The portion to the north of Latitude 39°30’ is largely adapted from the 40th Parallel Survey and that to the south of the 39th parallel form the papers and reports by Buwalda, Clark, Merriam, Hill, Spurr, and the unpublished work of H. G. Ferguson of the U. S. Geological Survey on the Hawthorne and Tonopah quadrangles.

  7. Effects of evapotranspiration heterogeneity on catchment water balance in the Southern Sierra Nevada of California

    Science.gov (United States)

    Kerkez, B.; Kelly, A. E.; Lucas, R. G.; Son, K.; Glaser, S. D.; Bales, R. C.

    2011-12-01

    Heterogeneity of Evapotranspiration (ET) is the result of poorly understood interactions between climate, topography, vegetation and soil. Accurate predictions of ET, and thus improved water balance estimates, hinge directly upon an improved understanding of the processes that drive ET across a wide spatio-temporal range. Recent warming trends in the Western US are shifting precipitation toward more rain-dominated patterns, significantly increasing vegetation water stress in historically snow-dominated regimes due to reduced soil moisture and increased vapor deficit during warm summer months. We investigate dominant controls that govern ET variability in a highly instrumented 1km2 mountain catchment at the Southern Sierra Critical Zone Observatory, co-located in the Kings River Experimental Watershed. Various ET estimates are derived from a number of measurement approaches: an eddy flux covariance tower, ET chambers, stream flumes, groundwater monitoring wells, matric potential sensors, as well as data from a distributed wireless sensor network with over 300 sensors. Combined with precipitation data, and high-density distributed soil moisture and snowdepth readings, the ET estimates are utilized to reconstruct the overall catchment water balance. We also apply the Regional Hydro-Ecologic Simulation System (RHESSys), a physically based, spatially distributed hydrologic model, to estimate water balance components. The model predictions are compared with the water budget calculated from field data, and used to identify the key variables controlling spatial and temporal patterns of ET at multiple scales. Initial results show that ET estimates are scale-, and vegetation-dependent, with significant ET variability between vegetation types and physiographic parameters such as elevation, slope, and aspect. In mixed conifer forests terrain, ET is more dependent on soil moisture, while in the meadows, where the soil is generally saturated for the duration of the growing

  8. Present importance of coffe production in some coffe grower communities and indian comunities in the Sierra Nevada de Santa Marta Importancia actual de la caficultora en algunas comunidades campesinas e indígenas de la Sierra Nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    Herrera Rojas Gilberto

    1993-12-01

    Full Text Available Coffe production followed by coffe growers and indian groups in the Sierra Nevada de Santa Marta, shows several differences regarding economical rationalityandtechnology. Coffe plays avery important role inthe economy and life quality ofthegrowers and indians. Traditional technology is generalized and has slowed down the deterioration of the Sierra, although life quality is very low.
    La caficultura que practican los campesinos y los grupos indlgenas de la Sierra Nevada de Santa Marta, tiene notables diferencias, tanto en la racionalidad económica, como en la lógica con la cual son atendidos los cultivos. El café juega un
    papel predominante en el sostenimiento de la economla
    y en la calidad de la vida de campecinos e indlgenas. La tecnologla tradicional, cuyo uso es generalizado, ha demorado el deterioro de ese inmenso maciso, aunuqe la calidad de la vida es bastante baja.

  9. Application of the Ecosystem Disturbance and Recovery Tracker in Detection of Forest Health Departure from Desired Conditions in Sierra Nevada National Forests

    Science.gov (United States)

    Slaton, M.; Koltunov, A.; Ramirez, C.

    2016-12-01

    Three Sierra Nevada national forests have recently released draft revised land management plans to the public for comment. These plans include components guiding land management projects (e.g. timber harvest) over the next decades. Desired conditions for land cover types were identified, and are based on the concept of the natural range of variability (NRV); the agency aims to achieve vegetation structure and composition that is within the range that has occurred in that system during the Holocene, prior to Euro-American settlement. Such systems are identified as having ecological integrity, with the ability to withstand and recover from disturbance. Comparisons between current conditions and the NRV period are often made qualitatively, with quantitative comparisons possible through the reconstruction of forest parameters using paleoecological evidence such as pollen or tree rings. Where such information is lacking, comparisons can be made using more recent data for locations or time periods believed to closely represent NRV. Such evaluations are necessary to develop projects that will be within the agency's desired conditions. As an example, the most recent estimate of the extent of tree mortality in CA continues to rise and expand at an aggressive rate, creating the need to track progress as compared to baseline conditions. The Ecosystem Disturbance and Recovery Tracker (eDaRT) is a system developed by the US Forest Service Region 5 Remote Sensing Lab and UC Davis CSTARS center that uses all available Landsat imagery to detect anomalies in vegetation indices, and has been adapted to detect current tree mortality as compared to modern pre-drought baseline conditions. We present initial results for the southern Sierra Nevada (5,260,913 hectares; 13 million acres) that have been validated using WorldView imagery and field data. The high spatial resolution and large extent of the dataset as compared to other mortality maps enabled identification of factors correlated

  10. Examining the Relationship Between Edaphic Variables and the Rooting System of Abies concolor in the southern Sierra Nevada

    Science.gov (United States)

    Wilson, A.; Jackson, R. B.; Tumber-Davila, S. J.

    2017-12-01

    An increase in the frequency and severity of droughts has been associated with the changing climate. These events have the potential to alter the composition and biogeography of forests, as well as increase tree mortality related to climate-induced stress. Already, an increase in tree mortality has been observed throughout the US. The recent drought in California led to millions of tree mortalities in the southern Sierra Nevada alone. In order to assess the potential impacts of these events on forest systems, it is imperative to understand what factors contribute to tree mortality. As plants become water-stressed, they may invest carbon more heavily belowground to reach a bigger pool of water, but their ability to adapt may be limited by the characteristics of the soil. In the Southern Sierra Critical Zone Observatory, a high tree mortality zone, we have selected both dead and living trees to examine the factors that contribute to root zone variability and belowground biomass investment by individual plants. A series of 15 cores surrounding the tree were taken to collect root and soil samples. These were then used to compare belowground rooting distributions with soil characteristics (texture, water holding capacity, pH, electric conductivity). Abies concolor is heavily affected by drought-induced mortality, therefore the rooting systems of dead Abies concolor trees were examined to determine the relationship between their rooting systems and environmental conditions. Examining the relationship between soil characteristics and rooting systems of trees may shed light on the plasticity of rooting systems and how trees adapt based on the characteristics of its environment. A better understanding of the factors that contribute to tree mortality can improve our ability to predict how forest systems may be impacted by climate-induced stress. Key words: Root systems, soil characteristics, drought, adaptation, terrestrial carbon, forest ecology

  11. Using wireless sensor networks to improve understanding of rain-on-snow events across the Sierra Nevada

    Science.gov (United States)

    Maurer, T.; Avanzi, F.; Oroza, C.; Malek, S. A.; Glaser, S. D.; Bales, R. C.; Conklin, M. H.

    2017-12-01

    We use data gathered from Wireless Sensor Networks (WSNs) between 2008 and 2017 to investigate the temporal/spatial patterns of rain-on-snow events in three river basins of California's Sierra Nevada. Rain-on-snow transitions occur across a broad elevation range (several hundred meters), both between storms and within a given storm, creating an opportunity to use spatially and temporally dense data to forecast and study them. WSNs collect snow depth; meteorological data; and soil moisture and temperature data across relatively dense sensor clusters. Ten to twelve measurement nodes per cluster are placed across 1-km2 areas in locations representative of snow patterns at larger scales. Combining precipitation and snow data from snow-pillow and climate stations with an estimation of dew-point temperature from WSNs, we determine the frequency, timing, and geographic extent of rain-on-snow events. We compare these results to WSN data to evaluate the impact of rain-on-snow events on snowpack energy balance, density, and depth as well as on soil moisture. Rain-on-snow events are compared to dry warm-weather days to identify the relative importance of rain and radiation as the primary energy input to the snowpack for snowmelt generation. An intercomparison of rain-on-snow events for the WSNs in the Feather, American, and Kings River basins captures the behavior across a 2° latitudinal range of the Sierra Nevada. Rain-on-snow events are potentially a more important streamflow generation mechanism in the lower-elevation Feather River basin. Snowmelt response to rain-on-snow events changes throughout the wet season, with later events resulting in more melt due to snow isothermal conditions, coarser grain size, and more-homogeneous snow stratigraphy. Regardless of snowmelt response, rain-on-snow events tend to result in decreasing snow depth and a corresponding increase in snow density. Our results demonstrate that strategically placed WSNs can provide the necessary data at

  12. Through the Looking Glass: Droughtorama to Snowpocalypse in the Sierra Nevada as studied with the NASA Airborne Snow Observatory

    Science.gov (United States)

    Painter, T. H.; Bormann, K.; Deems, J. S.; Hedrick, A. R.; Marks, D. G.; Skiles, M.; Stock, G. M.

    2017-12-01

    Across the last five years, the Sierra Nevada has seen increasing drought and then an abrupt return to a top five snowpack. Fortunately, the NASA Airborne Snow Observatory has been flying the Central Sierra Nevada since the spring of 2013, quantifying critical mountain basins' snow water equivalent and snow albedo. The huge variation of snowpack years captured by the NASA ASO is of enormous benefit to water cycle science, ecosystem science, and water management utilization of ASO data and its modeling. It allows a much broader understanding of mountain basin snow season cases for understanding snowmelt runoff, snow/rain mixes, snowfall distribution, evapotranspiration, soil moisture, and glacier mass balance. For water management, trust in empirical and physically-based modeling from the ASO data for application anywhere in the range of snow years is greatly improved by having consistency in that modeling with the span of years ASO has characterized. The NASA ASO was designed to characterize mountain snowpack and fill this void in water cycle science. Our original conversations with partner California Department of Water Resources in 2011 focused on the utility of ASO for flood risk mitigation, given the large snowfall of that year. However, from 2012 through 2016, California snowpacks expressed horrible drought, reaching the nadir in 2015 with the lowest snowpack on record. The 2016 snowpack was nearly normal according to snow pillows and snow courses (ASO's record is too short to define a `normal' year). However, 2017 had enormous snowfall in January and February, keeping snow pillows on track with the largest year on record, 1982-83. However, March backed off and the record year was lost. Still, accumulation was enormous. In parts of the San Joaquin basin, snow depths were > 30 m. The sum of near April 1 ASO total basin SWE for 2013 through 2016 in the Tuolumne Basin was only 92% of the near April 1, 2017 acquisition. In addition to the large accumulation of

  13. Socioeconomic effects of power marketing alternatives for the Central Valley and Washoe Projects: 2005 regional econmic impact analysis using IMPLAN

    International Nuclear Information System (INIS)

    Anderson, D.M.; Godoy-Kain, P.; Gu, A.Y.; Ulibarri, C.A.

    1996-11-01

    The Western Area Power Administration (Western) was founded by the Department of Energy Organization Act of 1977 to market and transmit federal hydroelectric power in 15 western states outside the Pacific Northwest, which is served by the Bonneville Power Administration. Western is divided into four independent Customer Service Regions including the Sierra Nevada Region (Sierra Nevada), the focus of this report. The Central Valley Project (CVP) and the Washoe Project provide the primary power resources marketed by Sierra Nevada. Sierra Nevada also purchases and markets power generated by the Bonneville Power Administration, Pacific Gas and Electric (PG ampersand E), and various power pools. Sierra Nevada currently markets approximately 1,480 megawatts of power to 77 customers in northern and central California. These customers include investor-owned utilities, public utilities, government agencies, military bases, and irrigation districts. Methods and conclusions from an economic analysis are summarized concerning distributional effects of alternative actions that Sierra Nevada could take with it's new marketing plan

  14. A new population record and conservation assessment of the Santa Marta Poison Arrow Frog Colostethus ruthveni Kaplan, 1997 (Anura: Dendrobatidae from Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    J.F.G. Maya

    2011-03-01

    Full Text Available Colombia possesses important amphibian species richness that is threatened by several factors. Here we report a new population of the Santa Marta Poison Arrow Frog Colostethus ruthveni, an endangered endemic species from Sierra Nevada de Santa Marta mountain range. During intensive surveys across Námaku Reserve, 22 C. ruthveni individuals (mean abundance 0.28 plus or minus 0.09 ind/km were observed along creeks between 737 and 923m above sea level near downtown Minca. This record represents a new locality for the species, increasing the number of known sites and expanding its extent of occurrence. We suggest the reassessment of the conservation status of the species from EN B1ab(iii to VU B1ab(iii, due to this and other recent findings. Currently, the species is present in three protected areas; this new record represents another reserve area where the species is distributed, ensuring the habitat and reducing some of its most important threats such as habitat loss and degradation from agricultural activities, logging, pollution and infrastructure development. This finding represents new critical information for the species and defines the need to understand the real status of its populations for future conservation strategies in the region.

  15. PLANTAS MEDICINALES USADAS POR LOS COGUI EN EL RÍO PALOMINO, SIERRA NEVADA DE SANTA MARTA (COLOMBIA

    Directory of Open Access Journals (Sweden)

    EDUINO CARBONÓ-DELAHOZ

    2013-12-01

    Full Text Available Con el propósito de registrar conocimientos tradicionales sobre plantas medicinales entre los Cogui o Kággaba en la cuenca del río Palomino, Sierra Nevada de Santa Marta (Colombia, se evaluó el uso de la flora con la aplicación de una técnica etnobotánica cuantitativa. Mediante entrevistas a mamos o sacerdotes-jefes, durante recorridos en áreas silvestres, cultivadas y huertos caseros en diferentes zonas climáticas de la cuenca, se obtuvo información de 189 especies utilizadas, incluidas en 162 géneros y 77 familias, así como el modo de uso y la forma de preparación para el tratamiento de enfermedades comunes. Las familias Asteraceae y Leguminosae registraron el mayor número de especies útiles. La evaluación con el índice de importancia relativa (IR permitió establecer que Ladenbergia moritziana (Rubiaceae, Stevia lucida (Asteraceae, Aniba sp. (Lauraceae, Erechtites hieracifolia (Asteraceae y Carex sp. (Cyperaceae son las especies con mayores valores de importancia. El 89 % de las plantas utilizadas es obtenido de espacios silvestres, lo que sugiere un conocimiento amplio de la diversidad vegetal local y el ejercicio de una práctica etnomédica.

  16. Processes affectin the chemistry of waters passing through a high elevator Sierra Nevada watershed. [U. S. A

    Energy Technology Data Exchange (ETDEWEB)

    Nodvin, S.C.

    1987-01-01

    The Eastern Brook Lakes watershed is located in the Sierra Nevada Mountains of California and spans and elevational range from 3060 to 3780 m. Changes in stream and lake chemistries along spatial and temporal flowpaths demonstrate that both terrestrial and aquatic processes were important in regulating surface water chemistries within the 250 ha watershed. Streams generally showed increasing pH, alkalinity, and conductance values with decreasing elevation. Large changes in stream chemistries occurred over short distances at locations such as alpine meadows. During the spring, stream alkalinities and conductance values decreased while stream pH values increased with time. pH values reached their maximim in June when alkalinity and conductance values were at their minimum values. Internal lake processes strongly influenced the chemistry of Upper Eastern Brook Lake. During spring and summer, lake waters exhibited near-neutral pH, low conductance (10-12 ..mu..S/cm), low alkalinity (100-120 ..mu..Eq/L), and undetectable ammonium. Under the ice, major changes in lake chemistry occurred associated with oxygen depletion in the hypolimnion. pH values decreased with time towards a minimum of 6.3 at 6 m depth. Other parameters increased w time and depth under the ice, reaching maximum values as follows: conductance > 80 ..mu..S/cm/sup -1/ Gran's alkalinity > 370 ..mu..Eq/L/sup -1/, and ammonium > 50 /sup m/u/sup E/q/L/sup -1/. 5 figures, 10 references.

  17. Distribution and stability of potential salmonid spawning gravels in steep boulder-bed streams of the eastern Sierra Nevada

    International Nuclear Information System (INIS)

    Kondolf, G.M.; Cada, G.F.; Sale, M.J.; Felando, T.

    1991-01-01

    Interest in small hydroelectric development (< 5 MW) has recently focused attention on steep streams and the resident trout populations they contain. High-gradient boulder-bed streams have been the sites of relatively few studies of salmonid spawning habitat, although they have geomorphic and hydraulic characteristics - and therefore gravel distributions - that are quite different from the more commonly described lower-gradient channels. The authors documented gravel distribution in seven high-gradient stream reaches in the eastern Sierra Nevada. Gravels occurred only in locations characterized by relatively low shear stress; they formed small pockets in sites of low divergence and larger deposits upstream of natural hydraulic controls. In 1986 (a wet year), all tracer gravels placed in gravel pockets at nine sites on four streams were completely swept away, and substantial scour, fill, and other channel changes occurred at many sites. In 1987 (a dry year), tracer gravels and the channel cross sections were generally stable. Periodic mobility of gravel may explain why brown trout Salmo trutta are more abundant than rainbow trout Oncorhychus mykiss in the study reaches, where high flows occur every May and June during snowmelt. Brown trout are fall spawners, and their fry emerge long before the high snowmelt flows, whereas rainbow trout are spring spawners whose eggs are in the gravel, and thus vulnerable to scour, during snowmelt flows

  18. Pre-eruptive conditions of the ~31 ka rhyolitic magma of Tlaloc volcano, Sierra Nevada Volcanic Range, Central Mexico

    Science.gov (United States)

    Macias, J.; Arce, J.; Rueda, H.; Gardner, J.

    2008-12-01

    Tlaloc volcano is located at the northern tip of the Sierra Nevada Volcanic Range in Central Mexico. This Pleistocene to Recent volcanic range consists from north to south of Tlaloc-Telapón-Teyotl-Iztaccíhuatl-and- Popocatépetl volcanoes. While andesitic to barely dacitic volcanism dominates the southern part of the range (i.e. Popocatépetl and Iztaccíhuatl); dacitic and rare rhyolithic volcanism (i.e. Telapón, Tlaloc) dominates the northern end. The known locus of rhyolitic magmatism took place at Tlaloc volcano with a Plinian-Subplinian eruption that occurred 31 ka ago. The eruption emplaced the so-called multilayered fallout and pumiceous pyroclastic flows (~2 km3 DRE). The deposit consists of 95% vol. of juvenile particles (pumice + crystals) and minor altered lithics 5% vol. The mineral association of the pumice fragments (74-76 % wt. SiO2) consists of quartz + plagioclase + sanidine + biotite and rare oxides set in a glassy groundmass with voids. Melt inclusions in quartz phenocrysts suggest that prior to the eruption the rhyolitic contain ~7% of H2O and Nevado de Toluca volcano (~6 km) some 50 km to the southwest.

  19. Application of Wildfire Risk Assessment Results to Wildfire Response Planning in the Southern Sierra Nevada, California, USA

    Directory of Open Access Journals (Sweden)

    Matthew P. Thompson

    2016-03-01

    Full Text Available How wildfires are managed is a key determinant of long-term socioecological resiliency and the ability to live with fire. Safe and effective response to fire requires effective pre-fire planning, which is the main focus of this paper. We review general principles of effective federal fire management planning in the U.S., and introduce a framework for incident response planning consistent with these principles. We contextualize this framework in relation to a wildland fire management continuum based on federal fire management policy in the U.S. The framework leverages recent advancements in spatial wildfire risk assessment—notably the joint concepts of in situ risk and source risk—and integrates assessment results with additional geospatial information to develop and map strategic response zones. We operationalize this framework in a geographic information system (GIS environment based on landscape attributes relevant to fire operations, and define Potential wildland fire Operational Delineations (PODs as the spatial unit of analysis for strategic response. Using results from a recent risk assessment performed on several National Forests in the Southern Sierra Nevada area of California, USA, we illustrate how POD-level summaries of risk metrics can reduce uncertainty surrounding potential losses and benefits given large fire occurrence, and lend themselves naturally to design of fire and fuel management strategies. To conclude we identify gaps, limitations, and uncertainties, and prioritize future work to support safe and effective incident response.

  20. Radiation balances of melting snow covers at an open site in the Central Sierra Nevada, California

    International Nuclear Information System (INIS)

    Aguado, E.

    1985-01-01

    The radiation balances of melting snow packs for three seasons at an open site at the Central Sierra Snow Laboratory near Soda Springs, California were examined. The snow covers were examples of below-normal, near-normal and much-above-normal water equivalents. Two of the snow covers melted under generally clear skies in late spring while the other melted under cloudier conditions and at a time when less extraterrestrial radiation was available. Moreover, the snow covers were of very different densities, thereby allowing examination of a possible relationship between that characteristic and albedo. No such relationship was observed. Despite the dissimilarities in the conditions under which melt occurred, the disposition of solar radiation was similar for the three melt seasons. Albedos and their rates of decline through the melt season were similar for the three seasons. Absorbed solar radiation and a cloudiness index were useful predictors for daily net radiation, accounting for 71% of the total variance. (author)

  1. Incorporating cold-air pooling into downscaled climate models increases potential refugia for snow-dependent species within the Sierra Nevada Ecoregion, CA.

    Directory of Open Access Journals (Sweden)

    Jennifer A Curtis

    Full Text Available We present a unique water-balance approach for modeling snowpack under historic, current and future climates throughout the Sierra Nevada Ecoregion. Our methodology uses a finer scale (270 m than previous regional studies and incorporates cold-air pooling, an atmospheric process that sustains cooler temperatures in topographic depressions thereby mitigating snowmelt. Our results are intended to support management and conservation of snow-dependent species, which requires characterization of suitable habitat under current and future climates. We use the wolverine (Gulo gulo as an example species and investigate potential habitat based on the depth and extent of spring snowpack within four National Park units with proposed wolverine reintroduction programs. Our estimates of change in spring snowpack conditions under current and future climates are consistent with recent studies that generally predict declining snowpack. However, model development at a finer scale and incorporation of cold-air pooling increased the persistence of April 1st snowpack. More specifically, incorporation of cold-air pooling into future climate projections increased April 1st snowpack by 6.5% when spatially averaged over the study region and the trajectory of declining April 1st snowpack reverses at mid-elevations where snow pack losses are mitigated by topographic shading and cold-air pooling. Under future climates with sustained or increased precipitation, our results indicate a high likelihood for the persistence of late spring snowpack at elevations above approximately 2,800 m and identify potential climate refugia sites for snow-dependent species at mid-elevations, where significant topographic shading and cold-air pooling potential exist.

  2. Preface to anthropogenic fluvial sedimentation: Centennial celebration of G.K. Gilbert's Hydraulic-Mining Débris in the Sierra Nevada

    Science.gov (United States)

    James, L. Allan; Phillips, Jonathan D.; Lecce, Scott A.

    2017-10-01

    This special issue celebrates the centennial of the publication of G.K. Gilbert's (1917) monograph, Hydraulic-Mining Débris in the Sierra Nevada, U.S. Geological Survey Professional Paper 105 (PP105). Reasons to celebrate PP105 are manifold. It was the last of four classic monographs that Gilbert wrote in a career that spanned five decades. The monograph, PP105, introduced several important concepts and provided an integrated view of watersheds that was uncommon in its day. It also provided an extreme, lucid example of anthropogenic changes and legacy sediment and how to approach such large-scale phenomena from an objective, quantitative basis.

  3. Some attempts at a geological explanation for the origin of the Sierra Nevada de Santa Marta in the Nineteenth Century: the naturalists Joaquin Acosta and Jorge Isaacs

    International Nuclear Information System (INIS)

    Castro Lopez, Pablo Antonio; Cardona Molina, Agustin

    2010-01-01

    The Sierra Nevada de Santa Marta, located in the northernmost part of Colombia, has been an object of scientific inquiry since at least the XIXth century, among other things because of its isolated character in relation to the Andean mountain chain. In this article we present some contributions to the knowledge of its origin and geological framework made by Joaquin Acosta (1800-1852) and Jorge Isaacs (1837-1895). Furthermore we establish a possible theoretical and conceptual relationship between these authors and some important European geologists and naturalists in the XIXth century, in the context of a history of ideas pertaining to orogenesis in Colombia.

  4. Incorporating Problem-Based Learning Into A Petrology Course Through A Research Project In The Local Northern Sierra Nevada

    Science.gov (United States)

    Aird, H. M.

    2016-12-01

    A research project into the local petrology was integrated into the Spring 2016 Petrology and Optical Mineralogy course at California State University, Chico. This is a required majors course, typically taken during spring of the junior year, with an enrollment of 10-20 students. Since the labs for this course have a strong focus on petrography, a research project was introduced to give students experience in using a multi-faceted approach to investigate a problem. In many cases, this is their first taste of research. During the first week of the Spring 2016 class, students were introduced to the research question: In the broader context of Californian tectonic history, are the Bucks Lake and Grizzly plutons of the northern Sierra Nevada petrogenetically related? With faculty guidance over the course of the semester, students carried out fieldwork and sampling, lithologic description, selection of the best samples for further analysis, thin section production, petrographic description, and analysis and interpretation of published geochemical data. Research activities were strategically scheduled within the course framework such that students were academically prepared to carry out each task. Each student was responsible for generating all the data for one sample, and data were then collated as a class, so students wrote their individual final reports using all the data collected by the class. Careful scaffolding of writing assignments throughout the semester guided students through the preparation of an academic-style scientific report, while allowing for repeated feedback on their writing style and content. In mid-May, the class presented a group poster at the College of Natural Sciences annual poster symposium, and were awarded `Best Student Class Project' by the judges. Anecdotal student feedback indicated they highly valued the research experience and some were inspired to pursue individual undergraduate research projects under faculty supervision.

  5. The influence of subsurface porosity and bedrock composition on ecosystem productivity and drought resilience in the Sierra Nevada Batholith, California

    Science.gov (United States)

    Riebe, C. S.; Callahan, R. P.; Goulden, M.; Pasquet, S.; Flinchum, B. A.; Taylor, N. J.; Holbrook, W. S.

    2017-12-01

    The availability of water and nutrients in soil and weathered rock influences the distribution of Earth's terrestrial life and regulates ecosystem vulnerability to land use and climate change. We explored these relationships by combining geochemical and geophysical measurements at three mid-elevation sites in the Sierra Nevada, California. Forest cover correlates strongly with bedrock composition across the sites, implying strong lithologic control on the ecosystem. We evaluated two hypotheses about bedrock-ecosystem connections: 1) that bedrock composition influences vegetation by moderating plant-essential nutrient supply; and 2) that bedrock composition influences the degree of subsurface weathering, which influences vegetation by controlling subsurface water-storage capacity. To quantify subsurface water-holding capacity, we used seismic refraction surveys to infer gradients in P and S-wave velocity structure, which reveal variations in porosity when coupled together in a Hertz-Mindlin rock-physics model. We combined the geophysical data on porosity with bedrock bulk geochemistry measured in previous work to evaluate the influence of water-holding capacity and nutrient supply on ecosystem productivity, which we quantified using remote sensing. Our results show that more than 80% of the variance in ecosystem productivity can be explained by differences in bedrock phosphorus concentration and subsurface porosity, with phosphorus content being the dominant explanatory variable. This suggests that bedrock composition exerts a strong bottom-up control on ecosystem productivity through its influence on nutrient supply and weathering susceptibility, which in turn influences porosity. We show that vegetation vulnerability to drought stress and mortality can be explained in part by variations in subsurface water-holding capacity and rock-derived nutrient supply.

  6. Oblique map showing maximum extent of 20,000-year-old (Tioga) glaciers, Yosemite National Park, central Sierra Nevada, California

    Science.gov (United States)

    Alpha, T.R.; Wahrhaftig, Clyde; Huber, N.K.

    1987-01-01

    This map shows the alpine ice field and associated valley glaciers at their maximum extent during the Tioga glaciation. The Tioga glaciation, which peaked about 15,000-20,OOO years ago, was the last major glaciation in the Sierra Nevada. The Tuolumne ice field fed not only the trunk glacier that moved down the Tuolumne River canyon through the present-day Hetch Hetchy Reservoir, but it also overflowed major ridge crests into many adjoining drainage systems. Some of the ice flowed over low passes to augment the flows moving from the Merced basin down through little Yosemite Valley. Tuolumne ice flowed southwest down the Tuolumne River into the Tenaya Lake basin and then down Tenaya Canyon to join the Merced glacier in Yosemite Valley. During the Tioga glaciation, the glacier in Yosemite Valley reached only as far as Bridalveil Meadow, although during a much earlier glaciation, a glacier extended about 10 miles farther down the Merced River to the vicinity of El Portal. Ice of the Tioga glaciation also flowed eastward from the summit region to cascade down the canyons that cut into the eastern escarpment of the Sierra Nevada [see errata, below]. Southeast of the present-day Yosemite Park, glaciers formed in the Mount Lyell region flowed east onto the Mono lowland and southeast and south down the Middle and North Forks of the San Joaquin River. In the southern part of the park, glaciers nearly reached to the present-day site of Wawona along the South Fork of the Merced River. At the time of the maximum extent of the Tioga glaciation, Lake Russell (Pleistocene Mono Lake) had a surface elevation of 6,800 feet, 425 feet higher than the 1980 elevation and 400 feet lower than its maximum level at the end of the Tioga glaciation. Only a few volcanic domes of the Mono Craters existed at the time of the Tioga glaciation. The distribution of vegetation, as suggested by the green overprint, is based on our interpretation. Forests were restricted to lower elevations than present

  7. Responses of Plant Community Composition to Long-term Changes in Snow Depth at the Great Basin Desert - Sierra Nevada ecotone.

    Science.gov (United States)

    Loik, M. E.

    2015-12-01

    Snowfall is the dominant hydrologic input for many high-elevation ecosystems of the western United States. Many climate models envision changes in California's Sierra Nevada snow pack characteristics, which would severely impact the storage and release of water for one of the world's largest economies. Given the importance of snowfall for future carbon cycling in high elevation ecosystems, how will these changes affect seedling recruitment, plant mortality, and community composition? To address this question, experiments utilize snow fences to manipulate snow depth and melt timing at a desert-montane ecotone in eastern California, USA. Long-term April 1 snow pack depth averages 1344 mm (1928-2015) but is highly variable from year to year. Snow fences increased equilibrium drift snow depth by 100%. Long-term changes in snow depth and melt timing are associated with s shift from shurbs to graminoids where snow depth was increased for >50 years. Changes in snow have impacted growth for only three plant species. Moreover, annual growth ring increments of the conifers Pinus jeffreyi and Pi. contorta were not equally sensitive to snow depth. There were over 8000 seedlings of the shrubs Artemisia tridentata and Purshia tridentata found in 6300 m2 in summer 2009, following about 1400 mm of winter snow and spring rain. The frequency of seedlings of A. tridentata and P. tridentata were much lower on increased-depth plots compared to ambient-depth, and reduced-depth plots. Survival of the first year was lowest for A. tridentata. Survival of seedlings from the 2008 cohort was much higher for P. tridentata than A. tridentata during the 2011-2015 drought. Results indicate complex interactions between snow depth and plant community characteristics, and that responses of plants at this ecotone may not respond similarly to increases vs. decreases in snow depth. These changes portend altered carbon uptake in this region under future snowfall scenarios.

  8. New Geologic Map and Structural Cross Sections of the Death Valley Extended Terrain (southern Sierra Nevada, California to Spring Mountains, Nevada): Toward 3D Kinematic Reconstructions

    Science.gov (United States)

    Lutz, B. M.; Axen, G. J.; Phillips, F. M.

    2017-12-01

    Tectonic reconstructions for the Death Valley extended terrain (S. Sierra Nevada to Spring Mountains) have evolved to include a growing number of offset markers for strike-slip fault systems but are mainly map view (2D) and do not incorporate a wealth of additional constraints. We present a new 1:300,000 digital geologic map and structural cross sections, which provide a geometric framework for stepwise 3D reconstructions of Late Cenozoic extension and transtension. 3D models will decipher complex relationships between strike-slip, normal, and detachment faults and their role in accommodating large magnitude extension/rigid block rotation. Fault coordination is key to understanding how extensional systems and transform margins evolve with changing boundary conditions. 3D geometric and kinematic analysis adds key strain compatibility unavailable in 2D reconstructions. The stratigraphic framework of Fridrich and Thompson (2011) is applied to rocks outside of Death Valley. Cenozoic basin deposits are grouped into 6 assemblages differentiated by age, provenance, and bounding unconformities, which reflect Pacific-North American plate boundary events. Pre-Cenozoic rocks are grouped for utility: for example, Cararra Formation equivalents are grouped because they form a Cordilleran thrust decollement zone. Offset markers are summarized in the associated tectonic map. Other constraints include fault geometries and slip rates, age, geometry and provenance of Cenozoic basins, gravity, cooling histories of footwalls, and limited seismic/well data. Cross sections were constructed parallel to net-transport directions of fault blocks. Surface fault geometries were compiled from previous mapping and projected to depth using seismic/gravity data. Cooling histories of footwalls guided geometric interpretation of uplifted detachment footwalls. Mesh surfaces will be generated from 2D section lines to create a framework for stepwise 3D reconstruction of extension and transtension in

  9. Correlation and origin of carnotite occurrences in the southern Nevada region

    International Nuclear Information System (INIS)

    Johnson, C.L.

    1982-01-01

    Carnotite [K 2 (UO 2 ) 2 (VO 4 ) 2 .3H 2 O] is recognized at seven localities in the southern Nevada region. These general areas of occurrence are the Jean-Sloan Calcrete, Hidden Valley Calcrete, Hualapai Limestone, Boulder City ''fossil water table'', Horse Spring Formation type locality, Mormon Mesa Caliche, and exposures of the Willow Tank thrust fault. The carnotite occurrences pre-date the 3.80 MY (million years before present) basalt at Sandy Pint, post-date an 8.66 MY tuff that underlies the Hualapai Limestone, and are approximately coeval with the 5.84 MY Fortification Basalt. Analysis of the Th/U ratios from 2045 dry stream sediment samples collected during the National Uranium Resource Evaluation (NURE) Program indicates uranium depletion in Precambrian terrain of the region and enrichment in areas where carnotite is observed. Anomalous vanadium in dry stream sediment samples is associated with intermediate and mafic Cenozoic volcanic rocks of pre-Colorado River age, and to a lesser extent with uratic Precambrian rocks. Correlation of the Jean-Sloan Calcrete, Hidden Valley Calcrete, Mormon Mesa Caliche, Hualapai Limestone, and Boulder City ''fossil water table'' is proposed based on elevation, relief, and inferred common age and origin. Carnotite studies have provided recognition criteria for facies of a regional geomorphic surface that formed in association with sluggish shallow groundwater flow in axial drainage systems in the Late Miocene. Carnotite and gypsum were deposited in disrupted by normal faulting and climatic conditions become increasingly arid 5-6 MY ago. Major geologic events that approximately coincide with the formation of the carnotite occurrences include the Messinian Crisis, opening of the Gulf of California, and uplift of the Sierra Nevada

  10. The Eastern delta-fan deposits on the Granada Basin as tectonic indicators of the Sierra Nevada uplift (Betic Cordillera, South Spain)

    Science.gov (United States)

    Roldán, Francisco Javier; Azañon, Jose Miguel; Mateos, Rosa Maria

    2014-05-01

    A geological mapping in detail of the Eastern sector of the Granada Basin (South Spain) reveals two different groups of Gilbert delta-fans related to the Sierra Nevada uplift. The first group, in the southern part and with a surface of 6 km2, has three major coarsening-upward sequences. They are composed of very coarse deposits, those of conglomerates, sands and silts. Progradational strata units to the basin have been observed. The dominantly fluvial facies association has locally developed shallow marine foreset deposits (partially with reef colonization) as well as topset red soils (Dabrio, et al., 1978; Braga et a., 1990; García-García, et al., 1999) . All the sequences are discordant over marine facies (calcarenites) dated over 8,26 Ma (Late Tortonian). The second group, in the northern part and with an extension of 12 km2, has similar characteristics, but some of the boulders have ostreids and lamellibranchs species which reveal their former position in a previous marine environment. The Sierra Nevada uplift caused the remobilization of these boulders, being transported by debris-flow inside the delta-fan bodies (García-García, et al., 2006). The dating of ostreids shells with Sr techniques reveals ages over 7,13, 6,61 and 5,45 Ma, from the lower to the upper delta-fan deposits, which are related to the three main sequences observed and with three major tectonic pulses during the Late Miocene. These interpretations are in agreement with apatite fision-track studies carried out in some boulders of these coarse delta-fan deposits (Clark and Dempster, 2013). They reveal a detailed record of Neogene denudation from the Sierra Nevada basement and with uplift periods between 5,45Ma- 2 Ma. The latest pulses affected the delta-fan sediments given rise to new fan systems in the Granada Basin (Alhambra Formation). The thoroughly study of the Miocene delta-fan sediments allows us to conclude that they were related to a sin-sedimentary tectonic activity linked to the

  11. Reproducción de Joturus pichardi y Agonostomus monticola(Mugiliformes: Mugilidae en ríos de la Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Pedro Eslava Eljaiek

    2011-12-01

    , specifically in Colombian freshwater environments. Reproductive biology of the mugilids J. pichardi and A. monticola from Sierra Nevada de Santa Marta (SNSM rivers was studied between July 2005 and December 2006. A total of 14 specimens of J. pichardi and 320 of A. monticola were collected. The reproductive biology was analyzed by means of: sexual proportion, gonadosomatic index, and mean size at maturity, fecundity and oocyte diameter. Additionally, a bioassay was carried out to evaluate the effect of salinity on spermatic motility and its possible relationship with the species’ spawning area. These mugilids share habitats with similar ecological characteristics, in which strong currents; clear water and stony areas stand out. Gonadal maturity indicators and indirect evidence are presented to support the relationship between reproductive maturity and higher rainfall levels in the area (September, October and November, as well as the catadromous migration of J. pichardi and A. monticola. This last species females outnumbered males with a sex ratio of 2.3:1. Females mean size at maturity was 172mm of their total length (TL and 108mm TL for males. Fecundity (F was 23 925±4 581 eggs per gram of gonad, and was related to size by the equation F=395.1TL1.281; besides, the mean oocyte diameter was 362±40μm. Considering the salinity effect on sperm motility in both species, results suggested that J. pichardi spawned in estuarine environments but the species did not migrate to fully marine environments; however, A. monticola withstood a broad range of salinity, suggesting a spawning from intermediate to total saline environments. Both species have high culturing potentials, considering that their feeding is based on plant and macroinvertebrates, their meat quality and the size they are able to reach. These species represent an interesting resource to the fisher groups of the region and should be integrally assessed. Rev. Biol. Trop. 59 (4: 1717-1728. Epub 2011 December 01.

  12. Variable-Resolution Ensemble Climatology Modeling of Sierra Nevada Snowpack within the Community Earth System Model (CESM)

    Science.gov (United States)

    Rhoades, A.; Ullrich, P. A.; Zarzycki, C. M.; Levy, M.; Taylor, M.

    2014-12-01

    Snowpack is crucial for the western USA, providing around 75% of the total fresh water supply (Cayan et al., 1996) and buffering against seasonal aridity impacts on agricultural, ecosystem, and urban water demands. The resilience of the California water system is largely dependent on natural stores provided by snowpack. This resilience has shown vulnerabilities due to anthropogenic global climate change. Historically, the northern Sierras showed a net decline of 50-75% in snow water equivalent (SWE) while the southern Sierras showed a net accumulation of 30% (Mote et al., 2005). Future trends of SWE highlight that western USA SWE may decline by 40-70% (Pierce and Cayan, 2013), snowfall may decrease by 25-40% (Pierce and Cayan, 2013), and more winter storms may tend towards rain rather than snow (Bales et al., 2006). The volatility of Sierran snowpack presents a need for scientific tools to help water managers and policy makers assess current and future trends. A burgeoning tool to analyze these trends comes in the form of variable-resolution global climate modeling (VRGCM). VRGCMs serve as a bridge between regional and global models and provide added resolution in areas of need, eliminate lateral boundary forcings, provide model runtime speed up, and utilize a common dynamical core, physics scheme and sub-grid scale parameterization package. A cubed-sphere variable-resolution grid with 25 km horizontal resolution over the western USA was developed for use in the Community Atmosphere Model (CAM) within the Community Earth System Model (CESM). A 25-year three-member ensemble climatology (1980-2005) is presented and major snowpack metrics such as SWE, snow depth, snow cover, and two-meter surface temperature are assessed. The ensemble simulation is also compared to observational, reanalysis, and WRF model datasets. The variable-resolution model provides a mechanism for reaching towards non-hydrostatic scales and simulations are currently being developed with refined

  13. Holocene climate aridification trend and human impact interrupted by millennial- and centennial-scale climate fluctuations from a new sedimentary record from Padul (Sierra Nevada, southern Iberian Peninsula)

    Science.gov (United States)

    Ramos-Román, María J.; Jiménez-Moreno, Gonzalo; Camuera, Jon; García-Alix, Antonio; Anderson, R. Scott; Jiménez-Espejo, Francisco J.; Carrión, José S.

    2018-01-01

    Holocene centennial-scale paleoenvironmental variability has been described in a multiproxy analysis (i.e., lithology, geochemistry, macrofossil, and microfossil analyses) of a paleoecological record from the Padul Basin in Sierra Nevada, southern Iberian Peninsula. This sequence covers a relevant time interval hitherto unreported in the studies of the Padul sedimentary sequence. The ˜ 4700-year record has preserved proxies of climate variability, with vegetation, lake levels, and sedimentological change during the Holocene in one of the most unique and southernmost wetlands in Europe. The progressive middle and late Holocene trend toward arid conditions identified by numerous authors in the western Mediterranean region, mostly related to a decrease in summer insolation, is also documented in this record; here it is also superimposed by centennial-scale variability in humidity. In turn, this record shows centennial-scale climate oscillations in temperature that correlate with well-known climatic events during the late Holocene in the western Mediterranean region, synchronous with variability in solar and atmospheric dynamics. The multiproxy Padul record first shows a transition from a relatively humid middle Holocene in the western Mediterranean region to more aridity from ˜ 4700 to ˜ 2800 cal yr BP. A relatively warm and humid period occurred between ˜ 2600 and ˜ 1600 cal yr BP, coinciding with persistent negative North Atlantic Oscillation (NAO) conditions and the historic Iberian-Roman Humid Period. Enhanced arid conditions, co-occurring with overall positive NAO conditions and increasing solar activity, are observed between ˜ 1550 and ˜ 450 cal yr BP (˜ 400 to ˜ 1400 CE) and colder and warmer conditions occurred during the Dark Ages and Medieval Climate Anomaly (MCA), respectively. Slightly wetter conditions took place during the end of the MCA and the first part of the Little Ice Age, which could be related to a change towards negative NAO conditions

  14. Holocene climate aridification trend and human impact interrupted by millennial- and centennial-scale climate fluctuations from a new sedimentary record from Padul (Sierra Nevada, southern Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    M. J. Ramos-Román

    2018-01-01

    Full Text Available Holocene centennial-scale paleoenvironmental variability has been described in a multiproxy analysis (i.e., lithology, geochemistry, macrofossil, and microfossil analyses of a paleoecological record from the Padul Basin in Sierra Nevada, southern Iberian Peninsula. This sequence covers a relevant time interval hitherto unreported in the studies of the Padul sedimentary sequence. The  ∼  4700-year record has preserved proxies of climate variability, with vegetation, lake levels, and sedimentological change during the Holocene in one of the most unique and southernmost wetlands in Europe. The progressive middle and late Holocene trend toward arid conditions identified by numerous authors in the western Mediterranean region, mostly related to a decrease in summer insolation, is also documented in this record; here it is also superimposed by centennial-scale variability in humidity. In turn, this record shows centennial-scale climate oscillations in temperature that correlate with well-known climatic events during the late Holocene in the western Mediterranean region, synchronous with variability in solar and atmospheric dynamics. The multiproxy Padul record first shows a transition from a relatively humid middle Holocene in the western Mediterranean region to more aridity from  ∼  4700 to  ∼  2800 cal yr BP. A relatively warm and humid period occurred between  ∼  2600 and  ∼  1600 cal yr BP, coinciding with persistent negative North Atlantic Oscillation (NAO conditions and the historic Iberian–Roman Humid Period. Enhanced arid conditions, co-occurring with overall positive NAO conditions and increasing solar activity, are observed between  ∼  1550 and  ∼  450 cal yr BP (∼  400 to  ∼  1400 CE and colder and warmer conditions occurred during the Dark Ages and Medieval Climate Anomaly (MCA, respectively. Slightly wetter conditions took place during the end of

  15. 40 CFR 81.115 - Northwest Nevada Intrastate Air Quality Control Region.

    Science.gov (United States)

    2010-07-01

    ... Quality Control Region. 81.115 Section 81.115 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.115 Northwest Nevada Intrastate Air Quality Control Region. The Northwest Nevada Intrastate Air Quality Control Region consists of the territorial area encompassed by the...

  16. High-resolution LIDAR and ground observations of snow cover in a complex forested terrain in the Sierra Nevada - implications for optical remote sensing of seasonal snow.

    Science.gov (United States)

    Kostadinov, T. S.; Harpold, A.; Hill, R.; McGwire, K.

    2017-12-01

    Seasonal snow cover is a key component of the hydrologic regime in many regions of the world, especially those in temperate latitudes with mountainous terrain and dry summers. Such regions support large human populations which depend on the mountain snowpack for their water supplies. It is thus important to quantify snow cover accurately and continuously in these regions. Optical remote-sensing methods are able to detect snow and leverage space-borne spectroradiometers with global coverage such as MODIS to produce global snow cover maps. However, snow is harder to detect accurately in mountainous forested terrain, where topography influences retrieval algorithms, and importantly - forest canopies complicate radiative transfer and obfuscate the snow. Current satellite snow cover algorithms assume that fractional snow-covered area (fSCA) under the canopy is the same as the fSCA in the visible portion of the pixel. In-situ observations and first principles considerations indicate otherwise, therefore there is a need for improvement of the under-canopy correction of snow cover. Here, we leverage multiple LIDAR overflights and in-situ observations with a distributed fiber-optic temperature sensor (DTS) to quantify snow cover under canopy as opposed to gap areas at the Sagehen Experimental Forest in the Northern Sierra Nevada, California, USA. Snow-off LIDAR overflights from 2014 are used to create a baseline high-resolution digital elevation model and classify pixels at 1 m resolution as canopy-covered or gap. Low canopy pixels are excluded from the analysis. Snow-on LIDAR overflights conducted by the Airborne Snow Observatory in 2016 are then used to classify all pixels as snow-covered or not and quantify fSCA under canopies vs. in gap areas over the Sagehen watershed. DTS observations are classified as snow-covered or not based on diel temperature fluctuations and used as validation for the LIDAR observations. LIDAR- and DTS-derived fSCA is also compared with

  17. Increasing resiliency in frequent fire forests: Lessons from the Sierra Nevada and western Australia

    Science.gov (United States)

    Scott L. Stephens

    2014-01-01

    This paper will primarily focus on the management and restoration of forests adapted to frequent, low-moderate intensity fire regimes. These are the forest types that are most at risk from large, high-severity wildfires and in many regions their fire regimes are changing. Fire as a landscape process can exhibit self-limiting characteristics in some forests which can...

  18. Soil microbial abundance, activity and diversity response in two different altitude-adapted plant communities affected by wildfire in Sierra Nevada National Park (Granada, Spain)

    Science.gov (United States)

    Bárcenas-Moreno, Gema; Zavala, Lorena; Jordan, Antonio; Bååth, Erland; Mataix-Beneyto, Jorge

    2013-04-01

    Plant communities can play an important role in fire severity and post-fire ecosystem recovery due to their role as combustible and different plant-soil microorganisms interactions. Possible differences induced by plant and microorganisms response after fire could affect the general ecosystem short and long-term response and its sustainability. The main objective of this work was the evaluation of the effect of wildfire on soil microbial abundance, activity and diversity in two different plant communities associated to different altitudes in Sierra Nevada National Park (Granada, Spain). Samples were collected in two areas located on the Sierra Nevada Mountain between 1700 and 2000 m above sea level which were affected by a large wildfire in 2005. Two samplings were carried out 8 and 20 months after fire and samples were collected in both burned and unburned (control) zones in each plant community area. Area A is located at 1700m and it is formed by Quercus rotundifolia forest while area B is located at 2000 m altitude and is composed of alpine vegetation formed by creeping bearing shrubs. Microbial biomass measured by Fumigation-Extraction method followed the same trend in both areas showing slight and no significant differences between burned and unburned area during the study period while viable and cultivable bacteria abundance were markedly higher in fire affected samples than in the control ones in both samplings. Viable and cultivable filamentous fungi had different behavior depending of plant vegetation community studied showing no differences between burned and unburned area in area A while was significantly higher in burned samples than in the control ones in area B. Microbial activity monitoring with soil microbial respiration appears to had been affected immediately after fire since microbial respiration was lower in burned samples from area A than in unburned one only 8 months after fire and no significant differences were observed between burned and

  19. A Multi-stakeholder Approach to Moving Beyond Tree Mortality in the Sierra Nevada

    Science.gov (United States)

    Balachowski, J.; Buluc, L.; Fischer, C.; Ko, J.; Ostoja, S.

    2017-12-01

    The US Forest Service has estimated that 102 million trees have died in California since 2010. This die off event has been attributed to the combined effects of historical land management practices, fire suppression, insect outbreaks, and climate-related stressors. This tree mortality event represents the largest and most significant ecological disturbance in California in centuries, if not longer. Both scientists and managers recognize the need to rethink our approach to forest management in the face of a changing climate and increasingly frequent, uncharacteristically large wildfires, while budgets and staffing capacity continue to decrease. Addressing the uncertainly in managing under climate change with fewer financial resources will require multiple partners and stakeholders—including federal and state agencies, local governments, and non-governmental organizations—to work together to identify common goals and paths moving forward. The USDA California Climate Hub and USFS Region 5 convened a symposium on drought and tree mortality in July 2017. With nearly 170 attendees across a wide range of sectors, the event provided a meaningful opportunity for reflection, analysis, and consideration of next steps. Among the outcomes of this symposium was the identification of areas in which our capacity for individual and synergistic action is stronger, and those in which it is lacking that will thus require additional attention and effort. From this symposium, which included a series of smaller, stakeholder and partner working groups, we collectively identified research and information needs, possible policy adjustments, future management actions, and funding needs and opportunities. Here, we present these findings and suggest approaches for addressing the current tree mortality event based on the shared interests of multiple, diverse stakeholder groups.

  20. CUES – A Study Site for Measuring Snowpack Energy Balance in the Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Edward H. Bair

    2015-09-01

    Full Text Available Accurate measurement and modeling of the snowpack energy balance are critical to understanding the terrestrial water cycle. Most of the water resources in the western US come from snowmelt, yet statistical runoff models that rely on the historical record are becoming less reliable because of a changing climate. For physically based snow melt models that do not depend on past conditions, ground based measurements of the energy balance components are imperative for verification. For this purpose, the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL and the University of California, Santa Barbara (UCSB established the CUES snow study site (CRREL/UCSB Energy Site, http://www.snow.ucsb.edu/ at 2940 m elevation on Mammoth Mountain, California. We describe CUES, provide an overview of research, share our experience with scientific measurements, and encourage future collaborative research. Snow measurements began near the current CUES site for ski area operations in 1969. In the 1970s, researchers began taking scientific measurements. Today, CUES benefits from year round gondola access and a fiber optic internet connection. Data loggers and computers automatically record and store over 100 measurements from more than 50 instruments each minute. CUES is one of only five high altitude mountain sites in the Western US where a full suite of energy balance components are measured. In addition to measuring snow on the ground at multiple locations, extensive radiometric and meteorological measurements are recorded. Some of the more novel measurements include scans by an automated terrestrial LiDAR, passive and active microwave imaging of snow stratigraphy, microscopic imaging of snow grains, snowflake imaging with a multi-angle camera, fluxes from upward and downward looking radiometers, snow water equivalent from different types of snow pillows, snowmelt from lysimeters, and concentration of impurities in the snowpack. We

  1. CUES - A Study Site for Measuring Snowpack Energy Balance in the Sierra Nevada

    Science.gov (United States)

    Bair, Edward; Dozier, Jeff; Davis, Robert; Colee, Michael; Claffey, Keran

    2015-09-01

    Accurate measurement and modeling of the snowpack energy balance are critical to understanding the terrestrial water cycle. Most of the water resources in the western US come from snowmelt, yet statistical runoff models that rely on the historical record are becoming less reliable because of a changing climate. For physically based snow melt models that do not depend on past conditions, ground based measurements of the energy balance components are imperative for verification. For this purpose, the US Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL) and the University of California, Santa Barbara (UCSB) established the “CUES” snow study site (CRREL/UCSB Energy Site, http://www.snow.ucsb.edu/) at 2940 m elevation on Mammoth Mountain, California. We describe CUES, provide an overview of research, share our experience with scientific measurements, and encourage future collaborative research. Snow measurements began near the current CUES site for ski area operations in 1969. In the 1970s, researchers began taking scientific measurements. Today, CUES benefits from year round gondola access and a fiber optic internet connection. Data loggers and computers automatically record and store over 100 measurements from more than 50 instruments each minute. CUES is one of only five high altitude mountain sites in the Western US where a full suite of energy balance components are measured. In addition to measuring snow on the ground at multiple locations, extensive radiometric and meteorological measurements are recorded. Some of the more novel measurements include scans by an automated terrestrial LiDAR, passive and active microwave imaging of snow stratigraphy, microscopic imaging of snow grains, snowflake imaging with a multi-angle camera, fluxes from upward and downward looking radiometers, snow water equivalent from different types of snow pillows, snowmelt from lysimeters, and concentration of impurities in the snowpack. We give an

  2. EL DISEÑO DE ITINERARIOS TURÍSTICOS PARA LA PUESTA EN VALOR DEL PATRIMONIO TERRITORIAL. LAS ACEQUIAS DE CAREO EN EL PARQUE NACIONAL DE SIERRA NEVADA

    Directory of Open Access Journals (Sweden)

    María José Prados Velasco

    2011-01-01

    Full Text Available Este artículo propone el diseño de itinerarios turísticos apoyados en el sistema de acequias de careo en la cuenca del Guadalfeo, en la vertiente sur del Parque Nacional de Sierra Nevada. Las acequias de careo son elementos claves empleados en la Antigüedad para la funcionalidad de los espacios agrarios de alta montaña en zonas semiáridas. En la actualidad constituyen elementos patrimoniales de primer orden que contribuyen al mantenimiento de los paisajes culturales. El objetivo central es el de vincular la sostenibilidad en la práctica del turismo, con la puesta en valor de elementos patrimoniales y paisajísticos.

  3. Temporal trend of the snow-related variables in Sierra Nevada in the last years: An analysis combining Earth Observation and hydrological modelling

    Science.gov (United States)

    Pérez-Luque, Antonio J.; Herrero, Javier; Bonet, Francisco J.; Pérez-Pérez, Ramón

    2016-04-01

    Climate change is causing declines in snow-cover extent and duration in European mountain ranges. This is especially important in Mediterranean mountain ranges where the observed trends towards precipitation and higher temperatures can provoke problems of water scarcity. In this work, we analyzed temporal trends (2000 to 2014) of snow-related variables obtained from satellite and modelling data in Sierra Nevada, a Mediterranean high-mountain range located in Southern Spain, at 37°N. Snow cover indicators (snow-cover duration, snow-cover onset dates and snow-cover melting dates) were obtained by processing images of MOD10A2 MODIS product using an automated workflow. Precipitation data were obtained using WiMMed, a complete and fully distributed hydrological model that is used to map the annual rainfall and snowfall with a resolution of 30x30 m over the whole study area. It uses expert algorithms to interpolate precipitation and temperature at an hourly scale, and simulates partition of precipitation into snowfall with several methods. For each snow-related indicator (snow-covers and snowfall), a trend analysis was applied at the MODIS pixel scale during the study period (2000-2014). We applied Mann-Kendall test and Theil-Sen slope estimation in each of the pixels comprising Sierra Nevada. The trend analysis assesses the intensity, magnitude and degree of statistical significance during the period analysed. The spatial pattern of these trends was explored according to elevation ranges. Finally, we explored the relationship between trends of snow-cover related indicators and precipitation trends. Our results show that snow-cover has undergone significant changes in the last 14 years. 80 % of the pixels covering Sierra Nevada showed a negative trend in the duration of snow-cover. We also observed a delay in the snow-cover onset date (68.03 % pixels showing a positive trend in the snow-cover onset date) and an advance in the melt date (80.72 % of pixels followed a

  4. A Blend of Ethanol and (-)-α-Pinene were Highly Attractive to Native Siricid Woodwasps (Siricidae, Siricinae) Infesting Conifers of the Sierra Nevada and the Allegheny Mountains.

    Science.gov (United States)

    Erbilgin, Nadir; Stein, Jack D; Acciavatti, Robert E; Gillette, Nancy E; Mori, Sylvia R; Bischel, Kristi; Cale, Jonathan A; Carvalho, Carline R; Wood, David L

    2017-02-01

    Woodwasps in Sirex and related genera are well-represented in North American conifer forests, but the chemical ecology of native woodwasps is limited to a few studies demonstrating their attraction to volatile host tree compounds, primarily monoterpene hydrocarbons and monoterpene alcohols. Thus, we systematically investigated woodwasp-host chemical interactions in California's Sierra Nevada and West Virginia's Allegheny Mountains. We first tested common conifer monoterpene hydrocarbons and found that (-)-α-pinene, (+)-3-carene, and (-)-β-pinene were the three most attractive compounds. Based on these results and those of earlier studies, we further tested three monoterpene hydrocarbons and four monoterpene alcohols along with ethanol in California: monoterpene hydrocarbons caught 72.3% of all woodwasps. Among monoterpene hydrocarbons, (+)-3-carene was the most attractive followed by (-)-β-pinene and (-)-α-pinene. Among alcohols, ethanol was the most attractive, catching 41.4% of woodwasps trapped. Subsequent tests were done with fewer selected compounds, including ethanol, 3-carene, and ethanol plus (-)-α-pinene in both Sierra Nevada and Allegheny Mountains. In both locations, ethanol plus (-)-α-pinene caught more woodwasps than other treatments. We discussed the implications of these results for understanding the chemical ecology of native woodwasps and invasive Sirex noctilio in North America. In California, 749 woodwasps were caught, representing five species: Sirex areolatus Cresson, Sirex behrensii Cresson, Sirex cyaneus Fabricius, Sirex longicauda Middlekauff, and Urocerus californicus Norton. In West Virginia 411 woodwasps were caught representing four species: Sirex edwardsii Brullé, Tremex columba Linnaeus, Sirex nigricornis F., and Urocerus cressoni Norton.

  5. Petrology and geochronology of metamorphosed volcanic rocks and a middle Cretaceous volcanic neck in the east-central Sierra Nevada, California.

    Science.gov (United States)

    Kistler, R.W.; Swanson, S.E.

    1981-01-01

    Metamorphosed Mesozoic volcanic rocks from the E-central Sierra Nevada range in composition from basalt to rhyolite and have ages, based on whole rock Rb-Sr and U-Pb zircon dating, of about 237- 224, 185, 163, 134, and 100Ma. The major plutons of the batholith in this area are of Triassic (215-200Ma) and Cretaceous (94-80Ma) ages. Initial 87Sr/86Sr values for the metamorphosed volcanic rocks of the area are in the range from 0.7042 to 0.7058 and are generally different from the values for the surrounding batholithic rocks (0.7056-0.7066). A circular, zoned granitic pluton, with an outcrop area of 2.5km2, similar in appearance to a ring dike complex, was apparently a conduit for some or possibly all of the middle-Cretaceous metamorphosed volcanic rocks exposed about 5km to the S in the western part of the Ritter Range. Samples from the metamorphosed volcanic rocks and the pluton yield a Rb/Sr whole rock isochron age of 99.9+ or -2.2Ma with an intitial 87Sr/86Sr of 0.7048+ or -0.00001. Major element variation diagrams of the pluton and volcanic rocks define coincident compositional trends. The ages of volcanic events relative to the ages of the major intrusive epochs and the major element and isotopic compositions of the volcanic rocks relative to the major plutons indicate that the volcanic rocks are not simply or directly related to the major plutons in the Sierra Nevada. -from Authors

  6. Fuel buildup and potential fire behavior after stand-replacing fires, logging fire-killed trees and herbicide shrub removal in Sierra Nevada forests

    Science.gov (United States)

    McGinnis, Thomas W.; Keeley, Jon E.; Stephens, Scott L.; Roller, Gary B.

    2010-01-01

    Typically, after large stand-replacing fires in mid-elevation Sierra Nevada forests, dense shrub fields occupy sites formerly occupied by mature conifers, until eventually conifers overtop and shade out shrubs. Attempting to reduce fuel loads and expedite forest regeneration in these areas, the USDA Forest Service often disrupts this cycle by the logging of fire-killed trees, replanting of conifers and killing of shrubs. We measured the effects of these treatments on live and dead fuel loads and alien species and modeled potential fire behavior and fire effects on regenerating forests. Sampling occurred in untreated, logged and herbicide-treated stands throughout the Sierra Nevada in four large fire areas 4–21 years after stand-replacing fires. Logging fire-killed trees significantly increased total available dead fuel loads in the short term but did not affect shrub cover, grass and forb cover, alien species cover or alien species richness. Despite the greater available dead fuel loads, fire behavior was not modeled to be different between logged and untreated stands, due to abundant shrub fuels in both logged and untreated stands. In contrast, the herbicide treatment directed at shrubs resulted in extremely low shrub cover, significantly greater alien species richness and significantly greater alien grass and forb cover. Grass and forb cover was strongly correlated with solar radiation on the ground, which may be the primary reason that grass and forb cover was higher in herbicide treated stands with low shrub and tree cover. Repeat burning exacerbated the alien grass problem in some stands. Although modeled surface fire flame lengths and rates of spread were found to be greater in stands dominated by shrubs, compared to low shrub cover conifer plantations, surface fire would still be intense enough to kill most trees, given their small size and low crown heights in the first two decades after planting.

  7. Managing Sierra Nevada forests

    Science.gov (United States)

    Malcolm North

    2012-01-01

    There has been widespread interest in applying new forest practices based on concepts presented in U.S. Forest Service General Technical Report PSW-GTR-220, "An Ecosystem Management Strategy for Sierran Mixed-Conifer Forests." This collection of papers (PSW-GTR-237) summarizes the state of the science in some topics relevant to this forest management approach...

  8. Continuous Lake-Sediment Records of Glaciation in the Sierra Nevada between 52,600 and 12,500 14C yr B.P

    Science.gov (United States)

    Benson, Larry V.; May, Howard M.; Antweiler, Ronald C.; Brinton, Terry I.; Kashgarian, Michaele; Smoot, Joseph P.; Lund, Steve P.

    1998-09-01

    The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial-interstadial oscillations. Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ˜24,500 and ended by ˜13,600 14C yr B.P. Many of the components of glacial rock flour (e.g., TiO 2, MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and SiO 2(amorphous) concentrations reached minimum values during Tioga glaciation, resulting from decreases in productivity that accompanied the introduction of rock flour into the surface waters of Owens Lake. At least 20 stadial-interstadial oscillations occurred in the Sierra Nevada between 52,600 and 14,000 14C yr B.P. Total organic carbon data from a Pyramid Lake sediment core also indicate oscillations in glacier activity between >39,500 and ˜13,600 14C yr B.P. Alpine glacier oscillations occurred on a frequency of ≤1900 yr in both basins, suggesting that millennial-scale oscillations occurred in California and Nevada during most of the past 52,600 yr.

  9. Radiocarbon and cation-radio ages for rock varnish on Tioga and Tahoe marainal boulders of Pine Creek, eastern Sierra Nevada, California, and their paleoclimatic implications

    Science.gov (United States)

    Dorn, R.I.; Turrin, B.D.; Jull, A.J.T.; Linick, T.W.; Donahue, D.J.

    1987-01-01

    Accelerator mass spectrometry 14C analyses of organic matter extracted from rock varnishes on morainal boulders yield limiting minimum ages for three crests of the Tioga glaciation. At Pine Creek in the eastern Sierra Nevada, varnish started to form on boulders of the outermost Tioga moraine before 19,000 yr B.P., and varnish originated on the innermost Tioga moraine before 13,200 yr B.P. Comparisons with lake-level, paleohydrological, paleoecological, colluvial, and rock varnish micromorphological data indicate that central-eastern California and western Nevada experienced a moisture-effective period during the late Pleistocene but after the Tioga maximum, and perhaps as Tioga glaciers receded from the mouth of Pine Creek canyon. Varnishes on Tahoeage morainal boulders at Pine Creek have cation-ratio ages of about 143,000-156,000 yr B.P., suggesting that the Tahoe glaciation should not be correlated with oxygen-isotope stage 4 in the early Wisconsin, but rather with stage 6. Varnishes on morainal boulders of an older glaciation at Pine Creek are dated by cation ratio at about 182,000-187,000 yr B.P. ?? 1987.

  10. Nevada

    International Nuclear Information System (INIS)

    Noble, D.C.; Plouff, D.; Close, T.J.; Bergquist, J.R.; Neumann, T.R.

    1987-01-01

    The part of the High Rock Late Wilderness Study Area, requested for mineral surveys by the Bureau of Land Management, encompasses 14,000 acres in the northern part of the Calico Mountains, Northwest Nevada. No resources were identified in the study area; however, there is low potential throughout the study area for volcanic-hosted deposits of mercury, uranium, and disseminated gold. The northern part of the study area has low potential for geothermal energy

  11. Mastication and prescribed fire impacts on fuels in a 25-year old ponderosa pine plantation, southern Sierra Nevada

    Science.gov (United States)

    Alicia L. Reiner; Nicole M. Vaillant; JoAnn Fites-Kaufman; Scott N. Dailey

    2009-01-01

    Due to increases in tree density and hazardous fuel loading in Sierra Nevadan forests, land management is focusing on fuel reduction treatments to moderate the risk of catastrophic fires. Fuel treatments involving mechanical and prescribed fire methods can reduce surface as well as canopy fuel loads. Mastication is a mechanical method which shreds smaller trees and...

  12. REGIONAL HYDROLOGY OF THE NOPAL I SITE, SIERRA DE PENA BLANCA, CHIHUAHUA, MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    J.A. Rodriguez-Pineda; P. Goodell; P.F. Dobson; J. Walton; R. Oliver; De La Garza; S. Harder

    2005-07-11

    The U.S. Department of Energy sponsored the drilling of three wells in 2003 near the Nopal I uranium deposit at the Sierra Pena Blanca, Chihuahua, Mexico. Piezometric information is being collected to understand groundwater flow at local and regional levels as part of an ongoing natural analogue study of radionuclide migration. Water level monitoring reported at these and other wells in the region is combined with archival data to provide a better understanding of the hydrology at Nopal I. Initial results suggest that the local hydrology is dependent on the regional hydrologic setting and that this groundwater system behaves as an unconfined aquifer. The region is dominated by an alternating sequence of highlands and basins that step down from west to east. The Sierra de Pena Blanca was downdropped from the cratonic block to the west during Cenozoic extension. The Nopal I area is near the intersection of two large listric faults, and the questa of ash flow tuffs that hosts the deposit has been subjected to complex structural events. The Pena Blanca Uranium District was originally characterized by 105 airborne radiometric anomalies, indicating widespread uranium mineralization. The Nopal I uranium deposit is located in the Sierra del Pena Blanca between the Encinillas Basin to the west, with a mean elevation of 1560 m, and the El Cuervo Basin to the east, with a mean elevation of 1230 m. The Nopal I + 10 level is at an intermediate elevation of 1463 m, with a corresponding groundwater elevation of approximately 1240 m. The regional potentiometric surface indicates flow from west to east, with the El Cuervo Basin being the discharge zone for the regional flow system. However, it appears that the local groundwater potential beneath the Nopal I site is more in accordance with the water table of the El Cuervo Basin than with that of the Encinillas Basin. This might indicate that there is limited groundwater flow between the Encinillas Basin and the Nopal I area.

  13. REGIONAL HYDROLOGY OF THE NOPAL I SITE, SIERRA DE PENA BLANCA, CHIHUAHUA, MEXICO

    International Nuclear Information System (INIS)

    Rodriguez-Pineda, J.A.; Goodell, P.; Dobson, P.F.; Walton, J.; Oliver, R.; De La Garza; Harder, S.

    2005-01-01

    The U.S. Department of Energy sponsored the drilling of three wells in 2003 near the Nopal I uranium deposit at the Sierra Pena Blanca, Chihuahua, Mexico. Piezometric information is being collected to understand groundwater flow at local and regional levels as part of an ongoing natural analogue study of radionuclide migration. Water level monitoring reported at these and other wells in the region is combined with archival data to provide a better understanding of the hydrology at Nopal I. Initial results suggest that the local hydrology is dependent on the regional hydrologic setting and that this groundwater system behaves as an unconfined aquifer. The region is dominated by an alternating sequence of highlands and basins that step down from west to east. The Sierra de Pena Blanca was downdropped from the cratonic block to the west during Cenozoic extension. The Nopal I area is near the intersection of two large listric faults, and the questa of ash flow tuffs that hosts the deposit has been subjected to complex structural events. The Pena Blanca Uranium District was originally characterized by 105 airborne radiometric anomalies, indicating widespread uranium mineralization. The Nopal I uranium deposit is located in the Sierra del Pena Blanca between the Encinillas Basin to the west, with a mean elevation of 1560 m, and the El Cuervo Basin to the east, with a mean elevation of 1230 m. The Nopal I + 10 level is at an intermediate elevation of 1463 m, with a corresponding groundwater elevation of approximately 1240 m. The regional potentiometric surface indicates flow from west to east, with the El Cuervo Basin being the discharge zone for the regional flow system. However, it appears that the local groundwater potential beneath the Nopal I site is more in accordance with the water table of the El Cuervo Basin than with that of the Encinillas Basin. This might indicate that there is limited groundwater flow between the Encinillas Basin and the Nopal I area

  14. Pleistocene lake outburst floods and fan formation along the eastern Sierra Nevada, California: implications for the interpretation of intermontane lacustrine records

    Science.gov (United States)

    Benn, Douglas I.; Owen, Lewis A.; Finkel, Robert C.; Clemmens, Samuel

    2006-11-01

    Variations in the rock flour fraction in intermontane lacustrine sediments have the potential to provide more complete records of glacier fluctuations than moraine sequences, which are subject to erosional censoring. Construction of glacial chronologies from such records relies on the assumption that rock flour concentration is a simple function of glacier extent. However, other factors may influence the delivery of glacigenic sediments to intermontane lakes, including paraglacial adjustment of slope and fluvial systems to deglaciation, variations in precipitation and snowmelt, and lake outburst floods. We have investigated the processes and chronology of sediment transport on the Tuttle and Lone Pine alluvial fans in the eastern Sierra Nevada, California, USA, to elucidate the links between former glacier systems located upstream and the long sedimentary record from Owens Lake located downstream. Aggradation of both fans reflects sedimentation by three contrasting process regimes: (1) high magnitude, catastrophic floods, (2) fluvial or glacifluvial river systems, and (3) debris flows and other slope processes. Flood deposits are represented by multiple boulder beds exposed in section, and extensive networks of large palaeochannels and boulder deposits on both fan surfaces. Palaeohydrological analysis implies peak discharges in the order of 10 3-10 4 m 3 s -1, most probably as the result of catastrophic drainage of ice-, moraine-, and landslide-dammed lakes. Cosmogenic radionuclide surface exposure dating shows that at least three flood events are represented on each fan, at 9-13, 16-18 and 32-44 ka (Tuttle Fan); and at ˜23-32, ˜80-86 ka, and a poorly constrained older event (Lone Pine Fan). Gravels and sands exposed in both fans represent fluvial and/or glacifluvial sediment transport from the Sierra Nevada into Owens Valley, and show that river systems incised and reworked older sediment stored in the fans. We argue that millennial-scale peaks in rock flour

  15. Tree mortality from fire and bark beetles following early and late season prescribed fires in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Schwilk, Dylan W.; Knapp, Eric E.; Ferrenberg, Scott; Keeley, Jon E.; Caprio, Anthony C.

    2006-01-01

    Over the last century, fire exclusion in the forests of the Sierra Nevada has allowed surface fuels to accumulate and has led to increased tree density. Stand composition has also been altered as shade tolerant tree species crowd out shade intolerant species. To restore forest structure and reduce the risk of large, intense fires, managers have increasingly used prescription burning. Most fires prior to EuroAmerican settlement occurred during the late summer and early fall and most prescribed burning has taken place during the latter part of this period. Poor air quality and lack of suitable burn windows during the fall, however, have resulted in a need to conduct more prescription burning earlier in the season. Previous reports have suggested that burning during the time when trees are actively growing may increase mortality rates due to fine root damage and/or bark beetle activity. This study examines the effects of fire on tree mortality and bark beetle attacks under prescription burning during early and late season. Replicated early season burn, late season burn and unburned control plots were established in an old-growth mixed conifer forest in the Sierra Nevada that had not experienced a fire in over 120 years. Although prescribed burns resulted in significant mortality of particularly the smallest tree size classes, no difference between early and late season burns was detected. Direct mortality due to fire was associated with fire intensity. Secondary mortality due to bark beetles was not significantly correlated with fire intensity. The probability of bark beetle attack on pines did not differ between early and late season burns, while the probability of bark beetle attack on firs was greater following early season burns. Overall tree mortality appeared to be primarily the result of fire intensity rather than tree phenology at the time of the burns. Early season burns are generally conducted under higher fuel moisture conditions, leading to less fuel

  16. Climate change and tree-line ecosystems in the Sierra Nevada: Habitat suitability modelling to inform high-elevation forest dynamics monitoring

    Science.gov (United States)

    Moore, Peggy E.; Alvarez, Otto; McKinney, Shawn T.; Li, Wenkai; Brooks, Matthew L.; Guo, Qinghua

    2017-01-01

    Whitebark pine and foxtail pine serve foundational roles in the subalpine zone of the Sierra Nevada. They provide the dominant structure in tree-line forests and regulate key ecosystem processes and community dynamics. Climate change models suggest that there will be changes in temperature regimes and in the timing and magnitude of precipitation within the current distribution of these species, and these changes may alter the species’ distributional limits. Other stressors include the non-native pathogen white pine blister rust and mountain pine beetle, which have played a role in the decline of whitebark pine throughout much of its range. The National Park Service is monitoring status and trends of these species. This report provides complementary information in the form of habitat suitability models to predict climate change impacts on the future distribution of these species within Sierra Nevada national parks.We used maximum entropy modeling to build habitat suitability models by relating species occurrence to environmental variables. Species occurrence was available from 328 locations for whitebark pine and 244 for foxtail pine across the species’ distributions within the parks. We constructed current climate surfaces for modeling by interpolating data from weather stations. Climate surfaces included mean, minimum, and maximum temperature and total precipitation for January, April, July, and October. We downscaled five general circulation models for the 2050s and the 2090s from ~125 km2 to 1 km2 under both an optimistic and an extreme climate scenario to bracket potential climatic change and its influence on projected suitable habitat. To describe anticipated changes in the distribution of suitable habitat, we compared, for each species, climate scenario, and time period, the current models with future models in terms of proportional change in habitat size, elevation distribution, model center points, and where habitat is predicted to expand or contract

  17. Prevalencia de patologías tropicales y factores de riesgo en la comunidad indígena de bunkwimake, sierra nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    Juan C. Dib

    2013-10-01

    Full Text Available Las enfermedades tropicales son endémicas en la Sierra Nevada de Santa Marta, sin embargo se carece de información acerca de la distribución de estas enfermedades en las comunidades indígenas que la habitan. Mediante estudios entomológicos y seroepidemiológicos, se estudiaron los factores de riesgo y la prevalencia de enfermedad de Chagas, leishmaniosis, hepatitis B y parasitosis intestinales en la comunidad indígena de Bunkwimake, ubicada en la vertiente norte de la Sierra Nevada. Los resultados de los estudios serológicos en 94 individuos reportaron una positividad de 18 (19%, 52(55% y 19(20% para infección por Tripanosoma cruzi, leishmania y el virus de la hepatitis B respectivamente. Adicionalmente, en 41(74% de 56 niños indígenas se encontró la presencia de parasitosis intestinales al examen coprológico. En los estudios entomológicos se captu-raron 37 triatominos en 16 viviendas distribuidos de la siguiente manera: 13 Triatoma dimidiata, 12 Rhodnius prolixus y 12 Pastrongylus geniculatus. Las tres especies se encontraron colonizando las viviendas indígenas y presentaron infeccilón para Trypanosoma cruzi. Dos especies de flebotominos fueron capturados en las vivien-das: 5 lutzomyia Gomezi y 7 Lutzomyia hirsute hirsute. El presente estudio demostró una importante prevalencia de infección por T. Cruzi y Leishmania en la población infantil, indicando transmisión reciente de ambas infec-ciones. Adicionalmente, los estudios entomológicos indican que existe un riesgo de transmisión doméstica de T. Cruzi y Leishmania por especies selváticas de triatominos y flebotominos. Se necesitan estudios adicionales que determinen la ecoepidemiología y dinámicas de trasnmisión de la Leishmanisosis y la enfermedad de Chagas en esta población para diseñar estrategias de control más adecuadas. Debido a que los programas verticales de fumigación y mejoramiento de vivienda en las comunidades indígenas no son viables, nuevas

  18. Uranium-thorium dating of quaternary carbonate accumulations in the Nevada Test Site region, southern Nevada

    International Nuclear Information System (INIS)

    Szabo, B.J.; Carr, W.J.; Gottschall, W.C.

    1981-01-01

    A useful way to approach the problem of tectonic activity in an arid region is through study of the history of movement of faults and fractures and of the young alluvial material they displace. Easily datable materials are scarce in these deposits, but carbonates such as caliche, calcrete, travertine, calcite vein, and tufa are common. Several types of these carbonates from the Nevada Test Site area in the southern Great Basin have been collected and dated by the uranium-series method. A variety of geologic settings are represented. The carbonate samples were subjected to a complex treatment process, and the resulting preparations were counted on an alpha spectrometer. Some of the samples from obviously closed systems yielded reasonable ages; others gave only a minimum age for a material or event. Many of the ages obtained agree well with estimates of age determined from dated volcanic units, fault-scarp morphology, and displaced alluvial units. Among the significant ages obtained were three dates of greater than 400,000 years on calcite-filling fractures above and below the water table in an exploratory drill hole for a possible candidate nuclear waste repository site at Yucca Mountain. Another date on calcrete from immediately below the youngest basalt in the region gave an age of 345,000 years, which agrees extremely well with the K-Ar age determined for the basalt of about 300,000 years. Undisturbed travertine that fills faults in several areas gave ages from about 75,000 years to greater than 700,000 years. Soil caliche and calcretes slightly displaced or broken by repeated movement on faults gave minimum ages in the range from more than 5000 to more than about 25,000 years

  19. Arsenic associated with historical gold mining in the Sierra Nevada foothills: Case study and field trip guide for Empire Mine State Historic Park, California

    Science.gov (United States)

    Alpers, Charles N.; Myers, Perry A; Millsap, Daniel; Regnier, Tamsen B; Bowell, Robert J.; Alpers, Charles N.; Jamieson, Heather E.; Nordstrom, D. Kirk; Majzlan, Juraj

    2014-01-01

    The Empire Mine, together with other mines in the Grass Valley mining district, produced at least 21.3 million troy ounces (663 tonnes) of gold (Au) during the 1850s through the 1950s, making it the most productive hardrock Au mining district in California history (Clark 1970). The Empire Mine State Historic Park (Empire Mine SHP or EMSHP), established in 1975, provides the public with an opportunity to see many well-preserved features of the historic mining and mineral processing operations (CDPR 2014a).A legacy of Au mining at Empire Mine and elsewhere is contamination of mine wastes and associated soils, surface waters, and groundwaters with arsenic (As), mercury (Hg), lead (Pb), and other metals. At EMSHP, As has been the principal contaminant of concern and the focus of extensive remediation efforts over the past several years by the State of California, Department of Parks and Recreation (DPR) and Newmont USA, Ltd. In addition, the site is the main focus of a multidisciplinary research project on As bioavailability and bioaccessibility led by the California Department of Toxic Substances Control (DTSC) and funded by the U.S. Environmental Protection Agency’s (USEPA’s) Brownfields Program.This chapter was prepared as a guide for a field trip to EMSHP held on June 14, 2014, in conjunction with a short course on “Environmental Geochemistry, Mineralogy, and Microbiology of Arsenic” held in Nevada City, California on June 15–16, 2014. This guide contains background information on geological setting, mining history, and environmental history at EMSHP and other historical Au mining districts in the Sierra Nevada, followed by descriptions of the field trip stops.

  20. The remarkable occurrence of large rainfall-induced debris flows at two different locations on July 12, 2008, Southern Sierra Nevada, CA, USA

    Science.gov (United States)

    DeGraff, J.V.; Wagner, D.L.; Gallegos, A.J.; DeRose, M.; Shannon, C.; Ellsworth, T.

    2011-01-01

    On July 12, 2008, two convective cells about 155 km apart produced a brief period of intense rainfall triggering large debris flows in the southern Sierra Nevada. The northernmost cell was centered over Oak Creek Canyon, an east-flowing drainage, and its tributaries near Independence, CA, USA. About 5:00 P.M., debris flows passed down the South Fork and North Fork of Oak Creek to merge into a large single feature whose passage affected the historic Mt. Whitney Fish hatchery and blocked California State Highway 395. At about the same time, the southernmost cell was largely centered over Erskine Creek, a main tributary of the west-flowing Kern River. Debris flows issued from several branches to coalesce into a large debris flow that passed along Erskine Creek, through the town of Lake Isabella, CA, USA and into the Kern River. It was observed reaching Lake Isabella about 6:30 P.M. Both debris flows caused significant disruption and damage to local communities. ?? 2011 Springer-Verlag.

  1. Solar storm effects during Saint Patrick's Days in 2013 and 2015 on the Schumann resonances measured by the ELF station at Sierra Nevada (Spain)

    Science.gov (United States)

    Salinas, A.; Toledo-Redondo, S.; Navarro, E. A.; Fornieles-Callejón, J.; Portí, J. A.

    2016-12-01

    The effects of solar storms occurring during the days 17 to 19 March 2013 and 2015, St. Patrick's Day intervals, on Schumann resonances (SRs) have been studied. To do this, the experimental data recorded by the Juan Antonio Morente extremely low frequency station located at Sierra Nevada, Spain, have been processed in order to obtain hourly averaged information on the first three resonance modes. Results are compared with monthly averages of the SR data for each hour to detect deviations from the regular behavior. Evidence of significant changes in the peak amplitudes and frequencies of the SRs have been identified in the station's measurements and related to the coronal mass ejection impact in the magnetosphere, detected by in situ plasma measurements onboard spacecraft in the solar wind. However, the complicated nature of the Schumann resonances, dependent on multiple variables and subject to multiple unavoidable interferences (e.g., lightning or human radio sources), in conjunction with the complex magnetosphere-ionosphere-atmosphere coupling processes, makes it difficult to conclude that the observed deviations are exclusively due to the solar events mentioned. Results extracted from only two solar events cannot be considered as conclusive, and therefore, independent comparison with results reported by other research would seem advisable in future works on this subject.

  2. Climate variability during the deglaciation and Holocene in a high-altitude alpine lake deduced from the sedimentary record from Laguna Seca, Sierra Nevada, southern Iberian Peninsula

    Science.gov (United States)

    Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Anderson, R. Scott

    2017-04-01

    High-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), color and lithological analyses have been carried out on a 3.6 m-long sediment core from Laguna Seca, a high-elevation dry lake from Sierra Nevada mountain range, southern Spain. This is the longest sedimentary record retrieved from an alpine lake in southern Iberian Peninsula. Besides, alpine lakes are very sensitive environments to climate changes and previous studies showed that Laguna Seca could provide an excellent record to identify millennial-scale climate variations during deglaciation and the whole Holocene. XRF analyses, in particular high calcium and low K/Ca ratios, show aridity phases, very well represented during Last Glacial Maximum (LGM) and the Younger Dryas (YD). Arid events are also shown at ca. 8.1 ka BP, ca. 4.4 ka BP and the latest Holocene. On the other hand, negative values in calcium and positive values in K/Ca appear in the Bølling-Allerød (BA) and during the early Holocene until ca. 6 ka BP, indicating more humidity and higher run-off. A progressive aridification trend is also observed in the Holocene, changing from more humid conditions during the early Holocene to more aridity during the late Holocene.

  3. High abundances of potentially active ammonia-oxidizing bacteria and archaea in oligotrophic, high-altitude lakes of the Sierra Nevada, California, USA.

    Directory of Open Access Journals (Sweden)

    Curtis J Hayden

    Full Text Available Nitrification plays a central role in the nitrogen cycle by determining the oxidation state of nitrogen and its subsequent bioavailability and cycling. However, relatively little is known about the underlying ecology of the microbial communities that carry out nitrification in freshwater ecosystems--and particularly within high-altitude oligotrophic lakes, where nitrogen is frequently a limiting nutrient. We quantified ammonia-oxidizing archaea (AOA and bacteria (AOB in 9 high-altitude lakes (2289-3160 m in the Sierra Nevada, California, USA, in relation to spatial and biogeochemical data. Based on their ammonia monooxygenase (amoA genes, AOB and AOA were frequently detected. AOB were present in 88% of samples and were more abundant than AOA in all samples. Both groups showed >100 fold variation in abundance between different lakes, and were also variable through time within individual lakes. Nutrient concentrations (ammonium, nitrite, nitrate, and phosphate were generally low but also varied across and within lakes, suggestive of active internal nutrient cycling; AOB abundance was significantly correlated with phosphate (r(2 = 0.32, p<0.1, whereas AOA abundance was inversely correlated with lake elevation (r(2 = 0.43, p<0.05. We also measured low rates of ammonia oxidation--indicating that AOB, AOA, or both, may be biogeochemically active in these oligotrophic ecosystems. Our data indicate that dynamic populations of AOB and AOA are found in oligotrophic, high-altitude, freshwater lakes.

  4. A Gap-Filling Procedure for Hydrologic Data Based on Kalman Filtering and Expectation Maximization: Application to Data from the Wireless Sensor Networks of the Sierra Nevada

    Science.gov (United States)

    Coogan, A.; Avanzi, F.; Akella, R.; Conklin, M. H.; Bales, R. C.; Glaser, S. D.

    2017-12-01

    Automatic meteorological and snow stations provide large amounts of information at dense temporal resolution, but data quality is often compromised by noise and missing values. We present a new gap-filling and cleaning procedure for networks of these stations based on Kalman filtering and expectation maximization. Our method utilizes a multi-sensor, regime-switching Kalman filter to learn a latent process that captures dependencies between nearby stations and handles sharp changes in snowfall rate. Since the latent process is inferred using observations across working stations in the network, it can be used to fill in large data gaps for a malfunctioning station. The procedure was tested on meteorological and snow data from Wireless Sensor Networks (WSN) in the American River basin of the Sierra Nevada. Data include air temperature, relative humidity, and snow depth from dense networks of 10 to 12 stations within 1 km2 swaths. Both wet and dry water years have similar data issues. Data with artificially created gaps was used to quantify the method's performance. Our multi-sensor approach performs better than a single-sensor one, especially with large data gaps, as it learns and exploits the dominant underlying processes in snowpack at each site.

  5. Analysis of rhizobial endosymbionts of Vicia, Lathyrus and Trifolium species used to maintain mountain firewalls in Sierra Nevada National Park (South Spain).

    Science.gov (United States)

    Villadas, Pablo J; Lasa, Ana V; Martínez-Hidalgo, Pilar; Flores-Félix, José David; Martínez-Molina, Eustoquio; Toro, Nicolás; Velázquez, Encarna; Fernández-López, Manuel

    2017-03-01

    Forest fires lead to the annual disappearance of many natural formations that require the creation of firewall areas. They can be maintained by enriching their pastures with attractive plants for grazing livestock, mainly legumes, which have a high protein content and low dependence on N fertilizers due to their ability to establish nitrogen-fixing symbiosis with rhizobia. In this study, the rhizobia isolated from the nodules of six legumes from the genera Vicia, Lathyrus and Trifolium were analysed in a firewall zone established in Lanjarón (Granada) close to the Sierra Nevada National Park (Spain). The results showed a high genetic diversity of the isolated strains that had 3, 16, 14 and 13 different types of rrs, recA, atpD and glnII genes, respectively. All strains were phylogenetically close to the species from the Rhizobium leguminosarum group, although they were not identified as any of them. The isolated strains belonged to the symbiovars viciae and trifolii but high phylogenetic diversity was found within both symbiovars, since there were 16 and 14 nodC gene types, respectively. Some of these strains clustered with strains isolated in other countries and continents, but others formed atpD, recA, glnII and nodC clusters and lineages only found to date in this study. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Secondary metabolites of lichens in the snow zone of the Sierra Nevada in Mérida-Venezuela and their role in the absorption of ultraviolet radiation

    International Nuclear Information System (INIS)

    Rojas Fernández, J.A.; Balza Quintero, A.; Marcano, V.; Rojas, P.A.; Dávila Vera, D.; Peña Contreras, Z.; Mendoza Briceño, R.V.; Palacios Prü, E.

    2008-01-01

    Photochemical analyses of secondary compounds in lichens from the Venezuelan Andean snow zone were carried out in order to know the absorbance capacity of UV radiation at the UVA, UVB and UVC ranges and to determine its probable UV protective function. Spectrophotometric (UV) and fine layer chromatographic techniques (TLC) were utilized to separate and identify the compounds. UV radiation values were obtained from the Red Bioclimática del Parque Nacional Sierra Nevada de Mérida which constitutes a program supported by the University of Los Andes, Venezuela. Results indicated the existence of 22 species of lichens at the snow zone; 55% of these species showed a strong resistance to UVC radiation, 95% to UVB radiation, whereas the 100% revealed a strong resistance to UVA radiation. The substances that have the highest resistance to UVA and UVB radiation are characterized by having ester bonds among phenolic units depsids and constitute the most abundant products in lichens, whereas the substances having both ester and ether bonds among the two phenolic units depsidones revealed a higher capacity to absorb UVC radiation that could indicate a primitive origin [es

  7. Fire decreases arthropod abundance but increases diversity: Early and late season prescribed fire effects in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Ferrenberg, Scott; Schwilk, Dylan W.; Knapp, Eric E.; Groth, Eric; Keeley, Jon E.

    2006-01-01

    Prior to fire suppression in the 20th century, the mixed-conifer forests of the Sierra Nevada, California, U.S.A., historically burned in frequent fires that typically occurred during the late summer and early fall. Fire managers have been attempting to restore natural ecosystem processes through prescription burning, and have often favored burning during the fall in order to mimic historical fire regimes. Increasingly, however, prescription burning is also being done during the late spring and early summer in order to expand the window of opportunity for needed fuel reduction burning. The effect of prescribed fires outside of the historical fire season on forest arthropods is not known. The objective of this study was to compare the short-term effects of prescribed fires ignited in the early and late fire season on forest floor arthropods. Arthropod abundance and diversity were assessed using pitfall trapping in replicated burn units in Sequoia National Park, California. Overall, abundance of arthropods was lower in the burn treatments than in the unburned control. However, diversity tended to be greater in the burn treatments. Fire also altered the relative abundances of arthropod feeding guilds. No significant differences in arthropod community structure were found between early and late season burn treatments. Instead, changes in the arthropod community appeared to be driven largely by changes in fuel loading, vegetation, and habitat heterogeneity, all of which differed more between the burned and unburned treatments than between early and late season burn treatments.

  8. Geodesy and contemporary strain in the Yucca Mountain region, Nevada

    International Nuclear Information System (INIS)

    Keefer, W.R.; Coe, J.A.; Pezzopane, S.K.; Hunter, W.C.

    1997-01-01

    Geodetic surveys provide important information for estimating recent ground movement in support of seismotectonic investigations of the potential nuclear-waste storage site at Yucca Mountain, Nevada. Resurveys of established level lines document up to 22 millimeters of local subsidence related to the 1992 Little Skull Mountain earthquake, which is consistent with seismic data that show normal-slip rupture and with data from a regional trilateration network. Comparison of more recent surveys with a level line first established in 1907 suggests 3 to 13 centimeters of subsidence in the Crater Flat-Yucca Mountain structural depression that coincides with the Bare Mountain fault; small uplifts also were recorded near normal faults at Yucca Mountain. No significant deformation was recorded by a trilateration network over a 10-year period, except for coseismic deformation associated with the Little Skull Mountain earthquake, but meaningful results are limited by the short temporal period of that data set and the small rate of movement. Very long baseline interferometry that is capable of measuring direction and rates of deformation is likewise limited by a short history of observation, but rates of deformation between 8 and 13 millimeters per year across the basin and Range province are indicated by the available data

  9. Rates and timing of vertical-axis block rotations across the Sierra Nevada-Walker Lane transition in the Bodie Hills

    Science.gov (United States)

    Rood, D. H.; Herman, S.; Burbank, D.; Bogue, S.

    2008-12-01

    We use paleomagnetic data from Tertiary volcanic rocks to address the rates and timing of vertical-axis block rotation across the Sierra Nevada-Walker Lane transition in the Bodie Hills, California/Nevada. In zones of continental deformation, block rotations are an important mechanism for permanent stain accommodation, and thus may be crucial to testing geodetic block models and resolving geologic-geodetic slip discrepancies. In our study, data included in the paleomagetic site means are high quality AF demagnetization results (least squared fits that generally include 5-7 points with MAD values less than 1). Thermal demagnetization results match the AF directions, and both thermal demag and rockmag results indicate strong ChRM, mostly carried by single domain magnetite. The site means used to calculate the VGPs all have a95 values less than 10 (mostly 2-5) and include 6-11 sites each. Each site (and thus site mean) has a reasonably well-known structural correction. The VGP scatter values range from 12 to 16 degrees, indicating that they include appropriate secular variation. The mean declinations and 95 percent confidence limits for each VGP timeslice are statistically distinct from one another (71 ± 9, 39 ± 13, and 11 ± 11 degrees). The slope of a linear regression fit to the age versus declination data gives a rate of vertical axis block rotation of approximately 3-4 degrees/Myr. Fitting two separate lines to the age vs. declination data would indicate an increase in the rates of rotation since ~10 Ma. Two possible interpretations of the data are: (1) the rotations began during or before the Middle Miocene, or (2) rates of rotation were high initially (e.g. ~10 Ma) and decelerated until the Pliocene. These data have implications for the (1) timing and spatial extent of distributed strain accumulation related to the initiation of the San Andreas Fault-Eastern California Shear Zone-Walker Lane transform plate boundary, (2) transfer of transform plate boundary

  10. El Cuaternario en el macizo de Sierra Nevada. Evolución paleoambiental y paisaje a partir de la interpretación de registros naturales y documentos de época

    OpenAIRE

    Oliva, Marc; Gómez Ortiz, Antonio; Palacios Estremera, David; Salvador Franch, Ferran; Salvà i Catarineu, Montse

    2014-01-01

    El conocimiento relativo a la evolución ambiental cuaternaria en las montañas de la Península Ibérica ha avanzado sustancialmente en las últimas décadas. Particularmente significativos son los progresos realizados en el macizo de Sierra Nevada, en el sur peninsular. En este caso, los investigadores se han servido de registros naturales y fuentes documentales para reconstruir la dinámica ambiental desde la Última Glaciación y posterior deglaciación del macizo hasta su evolución reciente. Los c...

  11. 76 FR 36450 - Approval and Promulgation of Air Quality Implementation Plans; State of Nevada; Regional Haze...

    Science.gov (United States)

    2011-06-22

    ... regional haze. This legislation established the Grand Canyon Visibility Transport Commission (GCVTC), which... Canyon National Park (NP), Sycamore Canyon Wilderness Area (WA), Pine Mountain WA, Mazatal WA, and Sierra Ancha WA. In California, they are Desolation WA, Dome Land WA, Hoover WA, Joshua Tree NP, Kaiser WA...

  12. Effect of climate variability and management practices on carbon, water and energy fluxes of a young Ponderosa pine plantation in the Sierra Nevada (CA)

    Science.gov (United States)

    Misson, L.; Tang, J.; McKay, M.; Goldstein, A. H.

    2003-04-01

    Despite the range and importance of semi-arid Ponderosa pine ecosystem in the United States, stand-scale fluxes of carbon, water and energy of these ecosystems have rarely been studied. Our research at the Blodgett Forest Research Station in the Sierra Nevada of California is advocated to better understand how these fluxes of a mid-elevation, young pine plantation vary interannually in response to climate variability, and how they are impacted by management practices such as shrub removal and thinning. Fluxes of CO2, H2O, and energy have been measured continuously since May 1999 by the eddy covariance method. Environmental parameters such as wind direction and speed, air temperature and humidity, net and photosynthetically active radiation, soil temperature, soil moisture, soil heat flux, rain, and atmospheric pressure are also monitored. Additional continuous measurements at the site have included O3 concentration and flux, and concentration and fluxes of a wide variety of volatile organic compounds. The data set covers periods characterized by various levels of drought stress. Shrub was removed in the spring 1999 and a precommercial thinning of 2/3 of the trees was applied in the spring 2000. Even during the winter, the young Ponderosa pine plantation at Blodgett acted mainly as a sink of carbon during the four years of measurement. The decrease of leaf area index and thus photosynthesis caused by thinning is the main factor that caused lower uptake, but increased respiration also occurred. These effects are limited in time and magnitude due to the rapidly increasing leaf area index after thinning. Beside this, the ability of this young pine plantation to act as a sink of carbon was also influenced by interannual variability of climate. Drought is a regular feature of the climate of California, making water availability the major controller of gas exchange in summer and fall. Freezing temperatures limit CO2 ecosystem uptake during the winter and tree growth in

  13. [Relative abundance and microhabitat use by the frog Geobatrachus walkeri (Anura: Strabomantidae) in two habitats of Sierra Nevada de Santa Marta, Colombia].

    Science.gov (United States)

    Martínez Baños, Vera; Pacheco Florez, Vanesa; Ramírez-Pinilla, Martha P

    2011-06-01

    Geobatrachus walkeri belongs to a monotypic frog genus endemic to the San Lorenzo area, Sierra Nevada de Santa Marta, Colombia. This species has been categorized as endangered because of its small distribution area and the decline in the extent and quality of its habitat. It inhabits two forest types with different composition and structure, the native secondary forest and a pine plantation (dominated by Pinus patula). To compare the relative abundance and microhabitat use of this species in these habitat types, 30 quadrants/environment were distributed randomly. The individual number, microhabitat use and other aspects of its natural history were registered using visual encounter surveys in both sites, including non-sampled areas in the quadrants. The relative abundance of frogs was significantly different between habitats and among seasons. The highest abundance of G. walkeri relative to the total area was found in the pine plantation, being 2.3 times higher than in the natural forest. More frogs were significantly found during the rainy season; nevertheless, active individuals were also found during the dry season. Significant differences were found in the microhabitat use with respect to the forest type and season. The most frequently microhabitat used in the two forest types was the pine leaf-litter; besides, in the native forest, the microhabitat occupied more frequently presented medium and large size stones. Geobatrachus walkeri is a successful species in pine plantations, associated permanently to its leaf-litter environment where it seems to develop its entire life cycle. The clear modifications in the soils and water, derived from the introduction of the pine plantation in this area, seem not to have negatively affected the conservation and successful maintenance of this species.

  14. Reproducción de Joturus pichardi y Agonostomus monticola(Mugiliformes: Mugilidae en ríos de la Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Pedro Eslava Eljaiek

    2011-12-01

    Full Text Available Para los mugílidos de agua dulce Joturus pichardi y Agonostomus monticola se han documentado aspectos ecológicos y de distribución, principalmente para las poblaciones de América Central, sin embargo, hay poca información disponible de sus aspectos reproductivos, especialmente en ambientes de agua dulce de Colombia. Por lo tanto para ambas especies se estudió la biología reproductiva en ríos de la Sierra Nevada de Santa Marta durante julio de 2005 y diciembre de 2006. En total, 14 especímenes de J. pichardi y 320 A. monticola fueron capturados. Proporción sexual, índice gonadosomático, talla media de madurez, fecundidad y diámetros de los ovocitos fueron evaluados. Se realizó un bioensayo para observar el efecto de la salinidad sobre la movilidad espermática y su posible relación con el área de desove de las especies. Estos mugílidos comparten un hábitat con características ecológicas similares, de corrientes fuertes y claras y zonas pedregosas. Indicadores de madurez gonadal y evidencias indirectas son presentados y con los cuales se comprueba que el periodo reproductivo se encuentra relacionado con los mayores valores de precipitación de la zona (septiembre a noviembre, así como, la migración catádroma de J. pichardi y A. monticola. Estas especies representan un potencial de cultivo, dado su alimentación basada en vegetales y macroinvertebrados, la calidad de su carne y las tallas que pueden alcanzar, por lo cual, se deben efectuar estudios más profundos que revelen mayor información sobre su comportamiento y reproducción en cautividad.

  15. Responses of Tree Growths to Tree Size, Competition, and Topographic Conditions in Sierra Nevada Forests Using Bi-temporal Airborne LiDAR Data

    Science.gov (United States)

    Ma, Q.; Su, Y.; Tao, S.; Guo, Q.

    2016-12-01

    Trees in the Sierra Nevada (SN) forests are experiencing rapid changes due to human disturbances and climatic changes. An improved monitoring of tree growth and understanding of how tree growth responses to different impact factors, such as tree competition, forest density, topographic and hydrologic conditions, are urgently needed in tree growth modeling. Traditional tree growth modeling mainly relied on field survey, which was highly time-consuming and labor-intensive. Airborne Light detection and ranging System (ALS) is increasingly used in forest survey, due to its high efficiency and accuracy in three-dimensional tree structure delineation and terrain characterization. This study successfully detected individual tree growth in height (ΔH), crown area (ΔA), and crown volume (ΔV) over a five-year period (2007-2012) using bi-temporal ALS data in two conifer forest areas in SN. We further analyzed their responses to original tree size, competition indices, forest structure indices, and topographic environmental parameters at individual tree and forest stand scales. Our results indicated ΔH was strongly sensitive to topographic wetness index; whereas ΔA and ΔV were highly responsive to forest density and original tree sizes. These ALS based findings in ΔH were consistent with field measurements. Our study demonstrated the promising potential of using bi-temporal ALS data in forest growth measurements and analysis. A more comprehensive study over a longer temporal period and a wider range of forest stands would give better insights into tree growth in the SN, and provide useful guides for forest growth monitoring, modeling, and management.

  16. TEJIENDO ENTRE REDES DIVERSAS: REFLEXIONES A PARTIR DE UNA ETNOGRAFÍA MULTISITUADA CON LOS PUEBLOS INDÍGENAS DE LA SIERRA NEVADA DE SANTA MARTA, CARIBE COLOMBIANO

    Directory of Open Access Journals (Sweden)

    Ana Milena Horta Prieto

    2014-06-01

    Full Text Available La Sierra Nevada de Santa Marta, Colombia, es territorio de 4 pueblos indígenas: Kogui, Wiwa, Arhuaco y Kankuamo. Estos comparten la Ley de Sé, orden natural del universo, que en este trabajo se aborda como cosmopolitica (Stengers, a partir de la cual se gestiona la alteridad y se define la función de todos los seres existentes, desde una ontología animista (Descola. Los trabajos espirituales, entre los cuales se cuentan los pagamentos, son rituales en los que se realiza el tejido vital entre entidades, a partir del cual pueden circular los flujos energéticos y de pensamiento, que relacionan mamos (autoridades tradicionales, dueños de los existentes (Jaba y jate, y materiales sagrados, en una relación de intercambio que permite que las partes se reconfiguren y se apropien del sewá (conocimiento que cada uno posee. Algunos de estos materiales han sido removidos del territorio, frente a lo cual las organizaciones indígenas han comenzado un proceso de patrimonialización como estrategia de protección, interactuando con entidades del estado que tienen influencia en la configuración del mismo desde su dominio. En este marco, a partir de la categoría de cosmopolitica y del entendimiento del conocimiento indígena como epistemología, este trabajo reflexiona sobre el posicionamiento del antropóloga/o en ese ordenamiento desde donde se puede tejer entre redes de ontologías diferentes.

  17. Estructura, antiestructura y sistema-mundo en una comunidad alternativa. El caso de los “jipi-koguis” en la Sierra Nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    Jean Paul Sarrazin

    2016-01-01

    Full Text Available Utilizando los conceptos de estructura , antiestructura , liminalidad y sistema-mundo , este ensayo analiza algunas representaciones a propósito de los “jipi-koguis”, nombre que le ha sido atribuido a una comunidad hippie en la Sierra Nevada de Santa Marta (Co - lombia, fundada a principios de la década de los setenta cerca de un asentamiento indígena kogui. Este tipo de grupos se plan - tean como proyectos “por fuera de la estructura”, “antisistémi - cos”, “alternativos”, lo cual es sometido acá a un análisis crítico, ya que los sujetos que hacen parte de estos grupos pueden ser claramente identificados a través de roles y posiciones dentro de una estructura social. Por otro lado, en su búsqueda de cambios y admiración por una cierta diferencia, este tipo de proyectos pretenden inspirarse en “otras culturas” ―en este caso la indíge - na―, presuponiendo equivocadamente que estas están radical - mente separadas del sistema moderno occidental. Se demuestra además que los discursos e intencionalidades de los sujetos que buscan salirse del sistema occidental y capitalista no pueden en - tenderse por fuera de ese mismo sistema. Finalmente, argumen - tamos que este tipo de comunidades, aunque dicen oponerse a la estructura social, tienden a estructurarse ellas mismas a medi - da que pasa el tiempo, generalmente por razones económicas y políticas.

  18. Estudio de un brote epidémico de fiebre amarilla selvática en el pie de monte de La Sierra Nevada de Santa Marta, 1979

    Directory of Open Access Journals (Sweden)

    Hernando Vidales

    1981-12-01

    Full Text Available En 1979 se observó en Colombia una epidemia de fiebre amarilla selvática, en las estribaciones más bajas de la Sierra Nevada de Santa Marta, donde nunca antes se había registrado la enfermedad. Los casos ocurrieron en las cercanías de las ciudades de Valledupar y Santa Marta, por entonces infestadas con Aedes aegypti .Veinte de ellos fueron confirmados por examen histopatológico de hígado o por aislamiento de virus y en otros 36 se hizo un diagnóstico de presunción, con base en estudios clínicos, epidemiológicos y serológicos. Entre los primeros hubo 14 defunciones y entre los segundos 13. En las localidades urbanas del Brea se llevaron a cabo intensas campañas de lucha contra el A. aegyptiy de vacunación. No se registraron casos urbanos de la enfermedad. Los enfermos se infectaron en bosques estrechos de galería y en cafetales. donde previa y paralelamente se observó mortalidad en monos í Alouatta seniculus. El reconocimiento entomológico mostró en la región la presencia de 3 especies de Haemagogus, entre ellas H. janthinomys Con 745 mosquitos se hicieron 192 mezclas para intentar aislamiento de virus, habiéndose obtenido sólo uno positivo para fiebre amarilla, a partir de H. janthinomys. La epidemia descrita es un ejemplo mBs de la invasión del virus amarílico a nuevos "habitats" rurales,  con la consiguiente amenaza para las ciudades vecinas infestadas con A. aegypti, el riesgo de la urbanización del virus, lo cual exige la adopción inmediata de medidas para abatir el mosquito y para vacunar a la población expuesta.

  19. Simulated hydrologic responses to climate variations and change in the Merced, Carson, and American River basins, Sierra Nevada, California, 1900-2099 *

    Science.gov (United States)

    Dettinger, M.D.; Cayan, D.R.; Meyer, M.K.; Jeton, A.

    2004-01-01

    Hydrologic responses of river basins in the Sierra Nevada of California to historical and future climate variations and changes are assessed by simulating daily streamflow and water-balance responses to simulated climate variations over a continuous 200-yr period. The coupled atmosphere-ocean-ice-land Parallel Climate Model provides the simulated climate histories, and existing hydrologic models of the Merced, Carson, and American Rivers are used to simulate the basin responses. The historical simulations yield stationary climate and hydrologic variations through the first part of the 20th century until about 1975 when temperatures begin to warm noticeably and when snowmelt and streamflow peaks begin to occur progressively earlier within the seasonal cycle. A future climate simulated with business-as-usual increases in greenhouse-gas and aerosol radiative forcings continues those recent trends through the 21st century with an attendant +2.5??C warming and a hastening of snowmelt and streamflow within the seasonal cycle by almost a month. The various projected trends in the business-as-usual simulations become readily visible despite realistic simulated natural climatic and hydrologic variability by about 2025. In contrast to these changes that are mostly associated with streamflow timing, long-term average totals of streamflow and other hydrologic fluxes remain similar to the historical mean in all three simulations. A control simulation in which radiative forcings are held constant at 1995 levels for the 50 years following 1995 yields climate and streamflow timing conditions much like the 1980s and 1990s throughout its duration. The availability of continuous climate-change projection outputs and careful design of initial conditions and control experiments, like those utilized here, promise to improve the quality and usability of future climate-change impact assessments.

  20. The 16 May 2005 Flood in Yosemite National Park--A Glimpse into High-Country Flood Generation in the Sierra Nevada

    Science.gov (United States)

    Dettinger, M.; Lundquist, J.; Cayan, D.; Meyer, J.

    2006-12-01

    On 16 May 2005, a Pacific storm drew warm, wet subtropical air into the Sierra Nevada, causing moderate rains and major flooding. The flood raised Hetch Hetchy and Tenaya Lake levels markedly and inundated large parts of Yosemite Valley, requiring evacuations and raising public-safety concerns in Yosemite National Park. This was the first major flood to be recorded by the high-country hydroclimatic network in the Park. Since 2001, scientists from US Geological Survey, Scripps Institution of Oceanography, California Department of Water Resources, National Park Service, and other institutions have developed the network of over 30 streamflow and 50 air-temperature loggers at altitudes ranging from 3000 m above sea level, and 8 snow-instrumentation sites measuring snow-water contents, snow depths, radiation, soil moisture, and temperatures in air, snow, and soil. The network documented flooding that derived its runoff mostly from high-altitude rainfall on soils already wet due to the onset of snowmelt a few days earlier. Air temperatures during the storm were above freezing up to altitudes of nearly 3000 m, so that rain fell to as high as 3000 m, compared with normal winter snowlines nearer 1500 m. Streams flooded below 3000 m, and above that altitude did not flood or contribute much to the flooding below. Meanwhile, no significant snow-water content changes were measured. Thus this flood resulted from rain-through-snow runoff rather than rain-on-snow melting. In the Park as a whole, about five times more catchment area received rain, rather than snow, during this storm than during typical cool winter storms. Because the flood was more a result of the large area that received rainfall than of melting snow, snowpack reductions that are expected if recent warming trends continue would not have reduced the flood. Instead, the opportunity for warm storms may increase if warming continues, in which case the potential for this kind of flooding will increase.

  1. Efficient way back litters nutrient potential of a tropical forest of bank. Sierra Nevada of Santa Marta Colombia

    International Nuclear Information System (INIS)

    Fuentes Molina, Natalia; Rodriguez Barrios, Javier Alfredo

    2012-01-01

    In three representative forests along the River Gaira, (subtropical wet forest, subtropical moist forest and tropical thorn mount), were measured over six months (wet and dry seasons) fluxes of nitrogen and phosphorus through the litter. Concentrations of nutrients (nitrogen and phosphorus) in the litter were relatively similar in the three Nevada de Santa Marta Colombia. Fuentes, Rodriguez. vegetation types (1.71% n and 0.12% p for the subtropical moist forest, followed by the tropical thorn mount with 1.50% n and 0.10% p and the subtropical wet forest with 1.39% n and 0.08% p), with the most significant differences found for nitrogen, which is the major nutrient with the absolute maximum in the subtropical rain forest set in the middle stretch of the basin. The greatest returns on biomass and nutrients occurred in the subtropical moist forest and tropical thorn mount set in the middle and lower reaches of the basin. The leaves showed high concentration of n and consequently, given the high production values of the different fractions, a high potential return of n (78.6 kg ha-1 yr-1). The foliar p concentration showed a potential return of 4.9 kgha1yr-1 and high values of the indices of efficiency in their use (iev: 2888.5) and foliar resorption (ern: 98.2), was the nutrient most limiting.

  2. An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

    Directory of Open Access Journals (Sweden)

    Benjamin M. Sleeter

    2015-06-01

    Full Text Available Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization, often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC Special Report on Emission Scenarios (SRES were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent

  3. An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

    Science.gov (United States)

    Sleeter, Benjamin M.; Liu, Jinxun; Daniel, Colin; Frid, Leonardo; Zhu, Zhiliang

    2015-01-01

    Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization), often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS) to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM) of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC) Special Report on Emission Scenarios (SRES) were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS) ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent modeling

  4. Reproduction, abundance, and population growth for a fisher (Pekania pennanti) population in the Sierra National Forest, California

    Science.gov (United States)

    Rick A. Sweitzer; Viorel D. Popescu; Reginald H. Barrett; Kathryn L. Purcell; Craig M. Thompson

    2015-01-01

    In the west coast region of the United States, fishers (Pekania pennanti) exist in 2 remnant populations—1 in northern California and 1 in the southern Sierra Nevada, California—and 3 reintroduced populations (western Washington, southern Oregon, and northeastern California). The West Coast Distinct Population Segment of fishers encompassing all of...

  5. 75 FR 44942 - 2015 Resource Pool-Sierra Nevada Customer Service Region

    Science.gov (United States)

    2010-07-30

    ... California State University, Sacramento. 0.06140 2,052 Cawelo Water District 0.06140 2,052 Dry Creek...,052 South San Joaquin Irrigation District... 0.01400 468 Stockton, Port of 0.02421 809 Truckee Donner...

  6. Problemática indígena « el ", , " ,, declaración conjunta de las cuatro organizaciones indígenas de la sierra nevada de santa marta para la interlocución con el estado y la sociedad nacional

    OpenAIRE

    Organización Wiwa Yugumaitm Bunkwanarrwa (owybt); Organización Indígena Kankwama (aik); Cor.federoeion Indígena Tayrona (eít); Organízaeión Gonawindua Tayrona (ogt)

    2014-01-01

    Este documento responde a las preocupaciones comunes de las cuatro organiz"acio..: nes representativas de los pueblos indígenas de la Sierra Nevada (OWYBT, OIK, CIT, OGT), a la hora de trazar el futuro del territorio que desde los inicios del mundo  les fue encomendado por los Padres y Madresespirituales.

  7. Mercury Concentrations in Fish and Sediment within Streams are Influenced by Watershed and Landscape Variables including Historical Gold Mining in the Sierra Nevada, California

    Science.gov (United States)

    Alpers, C. N.; Yee, J. L.; Ackerman, J. T.; Orlando, J. L.; Slotton, D. G.; Marvin-DiPasquale, M. C.

    2015-12-01

    We compiled available data on total mercury (THg) and methylmercury (MeHg) concentrations in fish tissue and streambed sediment from stream sites in the Sierra Nevada, California, to assess whether spatial data, including information on historical mining, can be used to make robust predictions of fish fillet tissue THg concentrations. A total of 1,271 fish from five species collected at 103 sites during 1980-2012 were used for the modeling effort: 210 brown trout, 710 rainbow trout, 79 Sacramento pikeminnow, 93 Sacramento sucker, and 179 smallmouth bass. Sediment data were used from 73 sites, including 106 analyses of THg and 77 analyses of MeHg. The dataset included 391 fish (mostly rainbow trout) and 28 sediment samples collected explicitly for this study during 2011-12. Spatial data on historical mining included the USGS Mineral Resources Data System and publicly available maps and satellite photos showing the areas of hydraulic mine pits and other placer mines. Modeling was done using multivariate linear regression and multi-model inference using Akaike Information Criteria. Results indicate that fish THg, accounting for species and length, can be predicted using geospatial data on mining history together with other landscape characteristics including land use/land cover. A model requiring only geospatial data, with an R2 value of 0.61, predicted fish THg correctly with respect to over-or-under 0.2 μg/g wet weight (a California regulatory threshold) for 108 of 121 (89 %) size-species combinations tested. Data for THg in streambed sediment did not improve the geospatial-only model. However, data for sediment MeHg, loss on ignition (organic content), and percent of sediment less than 0.063 mm resulted in a slightly improved model, with an R2 value of 0.63. It is anticipated that these models will be useful to the State of California and others to predict areas where mercury concentrations in fish are likely to exceed regulatory criteria.

  8. Distribución espacial y temporal de larvas de Trichoptera (Insecta en el río Manzanares, Sierra Nevada de Santa Marta (Colombia

    Directory of Open Access Journals (Sweden)

    Daniel José Serna M

    2015-06-01

    Full Text Available Los insectos acuáticos son importantes como indicadores de calidad de aguas en ríos y arroyos. Uno de los grupos más abundantes son los Thichoptera, ellos juegan un papel importante por su papel funcional en los sistemas acuáticos. Por eso conocer su diversidad es prioritario. El objetivo de este estudio es conocer la estructura de la comunidad del orden Trichoptera y su dinámica espacio-temporal en relación con los microhábitats y algunas variables físicas y químicas, en la parte media y baja de la cuenca del río Manzanares (Sierra Nevada de Santa Marta, Colombia. Se muestrearon mensualmente ocho microhábitats entre agosto 2002 y febrero 2003, durante los periodos de lluvias y sequía. Se recolectaron 3 316 larvas, repartidas en tres subórdenes pertenecientes a 10 familias y 14 géneros; seis de estos géneros y una familia son los primeros registros para el departamento del Magdalena (Colombia. Los tricópteros presentaron la mayor abundancia y riqueza genérica en los microhábitats Hojarasca Corriente Lenta, Hojarasca Corriente Rápida y Piedra Corriente Rápida, donde Nectopsyche (28%, Leptonema (17% y Smicridea (15% fueron los géneros más predominantes. La estructura, y composición de los géneros del orden Trichoptera variaron en cada estación en función del régimen pluviométrico y las variables físicas y químicas presentadas en la localidad de estudio, evidenciando las menores abundancias y riqueza en los periodos de altas precipitaciones (octubre y noviembre y las mayores en épocas de precipitaciones bajas (diciembre, enero y febrero. De igual forma las estaciones con mayores valores de oxígeno disuelto y menores valores en temperatura y conductividad reportaron las mayores abundancias de tricópteros. Los tricópteros evidenciaron preferencias por microhábitats específicos, variación en su composición de acuerdo con los periodos climáticos y respuesta a los niveles de polución del río. Se recomienda

  9. Mesospheric OH layer altitude at midlatitudes: variability over the Sierra Nevada Observatory in Granada, Spain (37° N, 3° W)

    Science.gov (United States)

    García-Comas, Maya; José López-González, María; González-Galindo, Francisco; de la Rosa, José Luis; López-Puertas, Manuel; Shepherd, Marianna G.; Shepherd, Gordon G.

    2017-10-01

    The mesospheric OH layer varies on several timescales, primarily driven by variations in atomic oxygen, temperature, density and transport (advection). Vibrationally excited OH airglow intensity, rotational temperature and altitude are closely interrelated and thus accompany each other through these changes. A correct interpretation of the OH layer variability from airglow measurements requires the study of the three variables simultaneously. Ground-based instruments measure excited OH intensities and temperatures with high temporal resolution, but they do not generally observe altitude directly. Information on the layer height is crucial in order to identify the sources of its variability and the causes of discrepancies in measurements and models. We have used SABER space-based 2002-2015 data to infer an empirical function for predicting the altitude of the layer at midlatitudes from ground-based measurements of OH intensity and rotational temperature. In the course of the analysis, we found that the SABER altitude (weighted by the OH volume emission rate) at midlatitudes decreases at a rate of 40 m decade-1, accompanying an increase of 0.7 % decade-1 in OH intensity and a decrease of 0.6 K decade-1 in OH equivalent temperature. SABER OH altitude barely changes with the solar cycle, whereas OH intensity and temperature vary by 7.8 % per 100 s.f.u. and 3.9 K per 100 s.f.u., respectively. For application of the empirical function to Sierra Nevada Observatory SATI data, we have calculated OH intensity and temperature SATI-to-SABER transfer functions, which point to relative instrumental drifts of -1.3 % yr-1 and 0.8 K yr-1, respectively, and a temperature bias of 5.6 K. The SATI predicted altitude using the empirical function shows significant short-term variability caused by overlapping waves, which often produce changes of more than 3-4 km in a few hours, going along with 100 % and 40 K changes in intensity and temperature, respectively. SATI OH layer wave effects

  10. Hepatitis fulminante en la Sierra Nevada: Una forma de superinfección del virus delta con el virus de la hepatitis B.

    Directory of Open Access Journals (Sweden)

    Alvaro Villanueva

    1992-06-01

    Full Text Available Durante septiembre de 1980 a octubre de 1983, se realizó un estudio seroepidemiológico para hepatitis A y B, en 258 personas en una ciudad (Santa Marta población de 250.000 y tres pequeños municipios (Santa Rosalía, Julio Zawady y Aracataca, poblaciones de 768, 800 y 5.000 habitantes respectivamente. La presencia de hepatitis A se encontró en un 77 a 93% (IgG Hepatitis A. Hbs Ag o Anti-Hbs Ag en 30.5% de la población en dos municipios (Santa Rosalía y Julio Zawady, en 2.5% en el municipio de Aracataca y 48.5% en la ciudad de Santa Marta. La presencia del Agente Delta (Anti-delta en el suero se determinó también en estas mismas poblaciones, encontrándose ausente en la ciudad y uno de los municipios (Aracataca, en contraste con una prevalencia de 13.7% y 22% en Julio Zawady y Santa Rosalía (P: 0.0001. Se excluyeron por historia clínica, antecedentes de drogadicción, transfusiones, o prácticas homosexuales, como mecanismos de transmisión de los virus B y delta. En veinte pacientes con diagnóstico histopalógico de hepatitis fulminante y en quienes se descartaron otras etiologías se demostró la presencia serológica de los virus de la hepatitis By Delta. De estos veinte, diez provenían de Julio Zawady y los otros diez de Santa Rosalía. La evolución clínica de esta enfermedad fue indistinguible de otras causas de falla hepática aguda. La mortalidad de estas formas fulminantes de hepatitis alcanzaron hasta un 65%. Los corticoides no modificaron el curso de esta enfermedad. La población joven mostró mayor compromiso y peor diagnóstico (P:0.033. La hepatitis fulminante de la Sierra Nevada de Santa Marta es el resultado de la superinfección con el virus Delta sobre la infección virus B. La aparición simultánea de casos intrafamiliares sugiere una relación importante entre los grupos comprometidos, aunque la forma exacta de transmisión permanece aún desconocida.

  11. Geothermal systems of the Mono Basin-Long Valley region, eastern California and western Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, C.T.; Flynn, T.; Chapman, R.H.; Trexler, D.T.; Chase, G.R.; Bacon, C.F.; Ghusn, G. Jr.

    1985-01-01

    The region that includes Mono Basin, Long Valley, the Bridgeport-Bodie Hills area, and Aurora, in eastern California and western Nevada was studied to determine the possible causes and interactions of the geothermal anomalies in the Mono Basin-Long Valley region as a whole. A special goal of the study was to locate possible shallow bodies of magma and to determine their influence on the hydrothermal systems in the region. (ACR)

  12. One hundred years of solitude, accumulation and violence: A comparative historical analysis of the Sierra Nevada of Santa Marta Valley

    NARCIS (Netherlands)

    M.E. Bedoya Arias (María Eugenia )

    2013-01-01

    textabstractThis is an analysis of two moments in the Colombian history within a century of difference, where isolation, accumulation and violence interact in a region brought into the worlds’ imaginary by the Colombian novelist Gabriel García Márquez in One Hundred years of Solitude. A valley

  13. Paleozoic-involving thrust array in the central Sierras Interiores (South Pyrenean Zone, Central Pyrenees): regional implications

    Science.gov (United States)

    Rodriguez, L.; Cuevas, J.; Tubía, J. M.

    2012-04-01

    This work deals with the structural evolution of the Sierras Interiores between the Tena and Aragon valleys. The Sierras Interiores is a WNW-trending mountain range that bounds the South Pyrenean Zone to the north and that is characterized by a thrust-fold system with a strong lithological control that places preferably decollements in Triassic evaporites. In the studied area of the Sierras Interiores Cenomanian limestones cover discordantly the Paleozoic rocks of the Axial Zone because there is a stratigraphic lacuna developed from Triassic to Late Cretaceous times. A simple lithostratigraphy of the study area is made up of Late Cenomanian to Early Campanian limestones with grey colour and massive aspect in landscape (170 m, Lower calcareous section), Campanian to Maastrichtian brown coloured sandstones (400-600 m, Marboré sandstones) and, finally, Paleocene light-coloured massive limestones (130-230 m), that often generate the higher topographic levels of the Sierras Interiores due to their greater resistance to erosion. Above the sedimentary sequence of the Sierras Interiores, the Jaca Basin flysch succession crops out discordantly. Based on a detailed mapping of the studied area of the Sierras Interiores, together with well and structural data of the Jaca Basin (Lanaja, 1987; Rodríguez and Cuevas, 2008) we have constructed a 12 km long NS cross section, approximately parallel to the movement direction deduced for this region (Rodríguez et al., 2011). The main structure is a thrust array made up of at least four Paleozoic-involving thrusts (the deeper thrust system) of similar thickness in a probably piggyback sequence, some of which are blind thrusts that generate fold-propagation-folds in upper levels. The higher thrust of the thrust array crops out duplicating the lower calcareous section all over the Sierras Interiores. The emplacement of the deeper thrust system generated the tightness of previous structures: south directed piggyback duplexes (the upper

  14. Postorogenic emplacement of the Santa Marta Batholith, northwestern flank of the Sierra Nevada de Santa Marta (SNSM).

    Science.gov (United States)

    Sanchez Sierra, Johan Miguel Sebastian; Kammer, Andreas

    2017-04-01

    The Santa Marta Batholith (BSM) belongs to a Paleogene intrusive suite of the Santa Marta massif, an exhumed triangular block at the southern Caribbean margin. Its Paleogene age precludes its association to an active margin, although its emplacement was controlled by the flexure of the down-bent Southamerican plate. Its internal structure is outlined by a mafic border facies and a felsic core, both having a petrologic affinity to a TTG-suite. According to existing age data, the BSM consolidated sequentially from SW to NE, with a first pulse having crystallized at 56 Ma in the southern domain and a final pulse in the northern domain at 52-50 Ma. Pressures varied between 5-7 kb, corresponding to depths of 14-19 km. This study combines structural, thermochronological and geochemical data with an analysis of Anisotropy and Magnetic Susceptibility (AMS) and paleomagnetism. The SNSM had a clockwise rotation of 30 ° and the ASM results help distinguish between two fault-bounded structural domains. The southern domain is characterized by a magnetic foliation concordant to the contact of the host rock that dips toward the hinterland. The northern domain, in contrast, displays a N-S trending magnetic foliation that is oblique to the regional structural northeastern trend. This divergence is supported by the orientation of mineral lineations, enclaves and dikes. In spite of its arc signature, anomalies like enrichment in Ti, depletion of Nb-Ta and Zr-Hf, as well as flat REE patterns can be associated to the accumulation of crystallized mafic minerals from less-fractionated magmas. These data evidence mingling. Asymmetric internal organization, as indicated by a hinterland-dipping roof pendent, the structural setting at the margin of a thickened continental margin and its geochemical signature favor a scenario of a magma generation at a mid-crustal level and its consequent extrusion along a channel, that connected to the crustal bend of the continental plate that was

  15. Rb-Sr, K-Ar, and stable isotope evidence for the ages and sources of fluid components of gold-bearing quartz veins in the northern Sierra Nevada foothills metamorphic belt, California

    Science.gov (United States)

    Böhlke, John Karl; Kistler, R. W.

    1986-01-01

    Gold-bearing quartz veins occur in and near major fault zones in deformed oceanic and island-arc rocks west of the main outcrop of the Sierra Nevada composite batholith. Veins typically occupy minor reverse faults that crosscut blueschist to amphibolite-grade metamorphic rocks whose metamorphic ages range from early Paleozoic to Jurassic. Vein micas and carbonate-quartz-mica assemblages that formed by hydrothermal metasomatism of ultramafic wall rocks in the Alleghany, Grass Valley, Washington, and Mother Lode districts yield concordant K-Ar and Rb-Sr ages. The dated veins are significantly younger than prograde metamorphism, penetrative deformation, and accretion of their host rocks to the continental margin. New and previously published mineralization ages from 13 localities in the Sierra foothills range from about 140 to 110 m.y. ago, with mean and median between 120 and 115 m.y. The age relations suggest that mineralizing fluids were set in motion by deep magmatic activity related to the resumption of east-dipping subduction along the western margin of North America following the Late Jurassic Nevadan collision event.CO 2 -bearing fluids responsible for metasomatism and much of the vein mica, carbonate, albite, and quartz deposition in several northern mines were isotopically heavy (delta 18 O [asymp] 8-14ppm; delta D between about -10 and -50ppm) and do not resemble seawater, magmatic, or meteoric waters. Metasomatic and vein-filling mica, dolomite, magnesite, and quartz in altered ultramafic rocks generally formed from fluids with similar Sr and O isotope ratios at a given locality. Consistent quartz-mica delta 18 O fractionations (delta 18 O (sub Q-M) = 4.5-4.9ppm) from various localities imply uniform equilibration temperatures, probably between 300 degrees and 350 degrees C. On a local (mine) scale, fluids responsible for both carbonate alteration of mafic and ultramafic wall rocks and albitic alteration of felsic and pelitic rocks had similar Sr isotope

  16. Mesozoic and Cenozoic structural geology of the CP Hills, Nevada Test Site, Nye County, Nevada; and regional implications

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, S. John [Univ. of Nevada, Reno, NV (United States)

    1991-08-01

    Detailed mapping and structural analysis of upper Proterozoic and Paleozoic rocks in the CP Hills of the Nevada Test Site, together with analysis of published maps and cross sections and a reconnaissance of regional structural relations indicate that the CP thrust of Barnes and Poole (1968) actually comprises two separate, oppositely verging Mesozoic thrust systems: (1) the west-vergent CP thrust which is well exposed in the CP Hills and at Mine Mountain, and (2) the east-vergent Belted Range thrust located northwest of Yucca Flat. West-vergence of the CP thrust is indicated by large scale west-vergent recumbent folds in both its hangingwall and footwall and by the fact that the CP thrust ramps up section through hangingwall strata toward the northwest. Regional structural relations indicate that the CP thrust forms part of a narrow sigmoidal belt of west-vergent folding and thrusting traceable for over 180 km along strike. The Belted Range thrust represents earlier Mesozoic deformation that was probably related to the Last Chance thrust system in southeastern California, as suggested by earlier workers. A pre-Tertiary reconstruction of the Cordilleran fold and thrust belt in the region between the NTS and the Las Vegas Range bears a close resemblance to other regions of the Cordillera and has important implications for the development of hinterland-vergent deformation as well as for the probable magnitude of Tertiary extension north of Las Vegas Valley. Subsequent to Mesozoic deformation, the CP Hills were disrupted by at least two episodes of Tertiary extensional deformation: (1) an earlier episode represented by pre-middle Miocene low-angle normal faults, and (2) a later, post-11 Ma episode of high-angle normal faulting. Both episodes of extension were related to regional deformation, the latter of which has resulted in the present basin and range topography of the NTS region.

  17. Mesozoic and Cenozoic structural geology of the CP Hills, Nevada Test Site, Nye County, Nevada; and regional implications

    International Nuclear Information System (INIS)

    Caskey, S.J.

    1991-08-01

    Detailed mapping and structural analysis of upper Proterozoic and Paleozoic rocks in the CP Hills of the Nevada Test Site, together with analysis of published maps and cross sections and a reconnaissance of regional structural relations indicate that the CP thrust of Barnes and Poole (1968) actually comprises two separate, oppositely verging Mesozoic thrust systems: (1) the west-vergent CP thrust which is well exposed in the CP Hills and at Mine Mountain, and (2) the east-vergent Belted Range thrust located northwest of Yucca Flat. West-vergence of the CP thrust is indicated by large scale west-vergent recumbent folds in both its hangingwall and footwall and by the fact that the CP thrust ramps up section through hangingwall strata toward the northwest. Regional structural relations indicate that the CP thrust forms part of a narrow sigmoidal belt of west-vergent folding and thrusting traceable for over 180 km along strike. The Belted Range thrust represents earlier Mesozoic deformation that was probably related to the Last Chance thrust system in southeastern California, as suggested by earlier workers. A pre-Tertiary reconstruction of the Cordilleran fold and thrust belt in the region between the NTS and the Las Vegas Range bears a close resemblance to other regions of the Cordillera and has important implications for the development of hinterland-vergent deformation as well as for the probable magnitude of Tertiary extension north of Las Vegas Valley. Subsequent to Mesozoic deformation, the CP Hills were disrupted by at least two episodes of Tertiary extensional deformation: (1) an earlier episode represented by pre-middle Miocene low-angle normal faults, and (2) a later, post-11 Ma episode of high-angle normal faulting. Both episodes of extension were related to regional deformation, the latter of which has resulted in the present basin and range topography of the NTS region

  18. Regional polyphase deformation of the Eastern Sierras Pampeanas (Argentina Andean foreland): strengths and weaknesses of paleostress inversion

    Science.gov (United States)

    Traforti, Anna; Zampieri, Dario; Massironi, Matteo; Viola, Giulio; Alvarado, Patricia; Di Toro, Giulio

    2016-04-01

    The Eastern Sierras Pampeanas of central Argentina are composed of a series of basement-cored ranges, located in the Andean foreland c. 600 km east of the Andean Cordillera. Although uplift of the ranges is partly attributed to the regional Neogene evolution (Ramos et al. 2002), many questions remain as to the timing and style of deformation. In fact, the Eastern Sierras Pampeanas show compelling evidence of a long lasting brittle history (spanning the Early Carboniferous to Present time), characterised by several deformation events reflecting different tectonic regimes. Each deformation phase resulted in further strain increments accommodated by reactivation of inherited structures and rheological anisotropies (Martino 2003). In the framework of such a polyphase brittle tectonic evolution affecting highly anisotropic basement rocks, the application of paleostress inversion methods, though powerful, suffers from some shortcomings, such as the likely heterogeneous character of fault slip datasets and the possible reactivation of even highly misoriented structures, and thus requires careful analysis. The challenge is to gather sufficient fault-slip data, to develop a proper understanding of the regional evolution. This is done by the identification of internally consistent fault and fracture subsets (associated to distinct stress states on the basis of their geometric and kinematic compatibility) in order to generate a chronologically-constrained evolutionary conceptual model. Based on large fault-slip datasets collected in the Sierras de Cordoba (Eastern Sierras Pampeanas), reduced stress tensors have been generated and interpreted as part of an evolutionary model by considering the obtained results against: (i) existing K-Ar illite ages of fault gouges in the study area (Bense et al. 2013), (ii) the nature and orientation of pre-existing anisotropies and (iii) the present-day stress field due to the convergence of the Nazca and South America plates (main shortening

  19. Regional groundwater flow and tritium transport modeling and risk assessment of the underground test area, Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    None

    1997-10-01

    The groundwater flow system of the Nevada Test Site and surrounding region was evaluated to estimate the highest potential current and near-term risk to the public and the environment from groundwater contamination downgradient of the underground nuclear testing areas. The highest, or greatest, potential risk is estimated by assuming that several unusually rapid transport pathways as well as public and environmental exposures all occur simultaneously. These conservative assumptions may cause risks to be significantly overestimated. However, such a deliberate, conservative approach ensures that public health and environmental risks are not underestimated and allows prioritization of future work to minimize potential risks. Historical underground nuclear testing activities, particularly detonations near or below the water table, have contaminated groundwater near testing locations with radioactive and nonradioactive constituents. Tritium was selected as the contaminant of primary concern for this phase of the project because it is abundant, highly mobile, and represents the most significant contributor to the potential radiation dose to humans for the short term. It was also assumed that the predicted risk to human health and the environment from tritium exposure would reasonably represent the risk from other, less mobile radionuclides within the same time frame. Other contaminants will be investigated at a later date. Existing and newly collected hydrogeologic data were compiled for a large area of southern Nevada and California, encompassing the Nevada Test Site regional groundwater flow system. These data were used to develop numerical groundwater flow and tritium transport models for use in the prediction of tritium concentrations at hypothetical human and ecological receptor locations for a 200-year time frame. A numerical, steady-state regional groundwater flow model was developed to serve as the basis for the prediction of the movement of tritium from the

  20. A computer hydrogeologic model of the Nevada Test Site and surrounding region

    International Nuclear Information System (INIS)

    Gillson, R.; Hand, J.; Adams, P.; Lawrence, S.

    1996-01-01

    A three-dimensional, hydrogeologic model of the Nevada Test Site and surrounding region was developed as an element for regional groundwater flow and radionuclide transport models. The hydrogeologic model shows the distribution, thickness, and structural relationships of major aquifers and confining units, as conceived by a team of experts organized by the U.S. Department of Energy Nevada Operations Office. The model was created using Intergraph Corporation's Geographical Information System based Environmental Resource Management Application software. The study area encompasses more than 28,000 square kilometers in southern Nevada and Inyo County, California. Fifty-three geologic cross sections were constructed throughout the study area to provide a framework for the model. The lithology was simplified to 16 hydrostratigraphic units, and the geologic structures with minimal effect on groundwater flow were removed. Digitized cross sections, surface geology, and surface elevation data were the primary sources for the hydrogeologic model and database. Elevation data for the hydrostratigraphic units were posted, contoured, and gridded. Intergraph Corporation's three-dimensional visualization software, VOXEL trademark, was used to view the results interactively. The hydrogeologic database will be used in future flow modeling activities

  1. Problemática indígena « el ", , " ,, declaración conjunta de las cuatro organizaciones indígenas de la sierra nevada de santa marta para la interlocución con el estado y la sociedad nacional

    Directory of Open Access Journals (Sweden)

    Organización Wiwa Yugumaitm Bunkwanarrwa (owybt

    2014-02-01

    Full Text Available Este documento responde a las preocupaciones comunes de las cuatro organiz"acio..: nes representativas de los pueblos indígenas de la Sierra Nevada (OWYBT, OIK, CIT, OGT, a la hora de trazar el futuro del territorio que desde los inicios del mundo  les fue encomendado por los Padres y Madresespirituales.

  2. Evaluación biológica preliminar de extractos vegetales utilizados en la medicina tradicional de la Sierra Nevada deSanta Marta contra el veneno de la Bothrops asper

    Directory of Open Access Journals (Sweden)

    Willinton Barranco Pérez

    2013-10-01

    Full Text Available Title: Preliminary biological evaluation of plants extracts used in the Sierra Nevada de Santa Marta against the snake Bothrops asper venom.ResumenLa mordedura de serpientes constituye un problema de salubridad importante en muchos países tropicales y subtropicales, con un estimado de 2,5 millones de personas envenenadas cada año. En Colombia las especies Bothropsasper y Bothropsatrox son las causantes del 70 al 90 % de los accidentes registrados. Se estima que el 60% de estos accidentes son inicialmente tratados por curanderos tradicionales utilizando plantas medicinales en diferentes preparaciones. Este estudio evaluó la capacidad inhibitoria de cinco especies contra el efecto proteolítico y hemolítico indirecto inducido por el veneno de B. asper en ensayos in vitro.Las especies, que fueron seleccionadas de acuerdo a su uso en la medicina tradicional por parte de las comunidades campesinas de la Sierra Nevada de Santa Marta, fueron, Aristolochia máxima, Cissampelospareira, Equisetumbogotense, Mucunacfpruriens y una especie de la familia Asteraceae. La planta E. bogotense mostró los mayores porcentaje de inhibición contra la actividad de las fosfolipasas A2(42,29 %, así como la mayor precipitación de las proteínas en un rango de masas moleculares de 28,2 y 94,43 KDa. Al fraccionar el extracto de E. bogotense se obtuvieron cinco fracciones, las cuales presentaron un porcentaje de inhibición de 36,6 ± 1,07 a 46,1 ± 13,6. Adicionalmente se detectaron por métodos cualitativos núcleos como, alcaloides, esteroides y/o triterpenos, taninos, cumarinas y leucoantocianidinas. En estudio se reporta la actividad antiofídica en ensayos in vitro de la especie E. bogotense contra el veneno de la especie B.asper. (DUAZARY 2012 No. 2, 140 - 150AbstractIn Colombia the species Bothrops asper and Bothrops atrox are responsible for 70 to 90% of the snakebite accidents. Around 60% of these injuries are initially treated by traditional healers; they

  3. Abundancia relativa y uso de microhábitat de la rana Geobatrachus walkeri (Anura: Strabomantidae en dos hábitats en Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Vera Martínez Baños

    2011-06-01

    Full Text Available La rana Geobatrachus walkeri pertenece a un género monotípico y endémico del área de San Lorenzo, Sierra Nevada de Santa Marta, Colombia. La especie habita en el bosque secundario natural y en una plantación de pino (dominada por Pinus patula. Para comparar la abundancia relativa y el uso del microhábitat en estos dos hábitat y durante los períodos de máxima y mínima precipitación, se distribuyeron aleatoriamente 30 cuadrantes en cada bosque sobre los que se registraron el número de individuos y los microhábitats ocupados. Además se reconocieron otros aspectos de la historia natural mediante muestreo por encuentros casuales (VES, se incluye en los dos hábitats áreas no muestreadas por los cuadrantes. La mayor abundancia de ranas se obtuvo en la plantación de pino y durante la época de lluvias. El microhábitat más usado fue la hojarasca de pino. Geobatrachus walkeri es una especie exitosa en las plantaciones de pino, asociada permanentemente a su hojarasca en donde parece desarrollar todo su ciclo de vida. Las claras modificaciones derivadas de la introducción de las plantaciones de pino en el suelo y el agua, parecen no haber afectado la supervivencia y mantenimiento exitoso de esta especie categorizada como en peligro de extinción.Relative abundance and microhabitat use by the frog Geobatrachus walkeri (Anura:Strabomantidae in two habitats of Sierra Nevada de Santa Marta, Colombia. Geobatrachus walkeri belongs to a monotypic frog genus endemic to the San Lorenzo area, Sierra Nevada de Santa Marta, Colombia. This species has been categorized as endangered because of its small distribution area and the decline in the extent and quality of its habitat. It inhabits two forest types with different composition and structure, the native secondary forest and a pine plantation (dominated by Pinus patula. To compare the relative abundance and microhabitat use of this species in these habitat types, 30 quadrants/environment were

  4. Natural responses to Quaternary climatic change in the Nevada Test Site region

    International Nuclear Information System (INIS)

    Gibson, J.D.

    1993-01-01

    Migration of hazardous contaminants within geologic settings depends on natural processes. Climatic fluctuations can affect the magnitudes and rates of many of these processes. In any long-term environmental evaluation of natural processes, responses to climatic change must be considered. Four generalized categories of natural responses to Quaternary climatic change are recognized for the Nevada Test Site (NTS) region of southwestern Nevada and adjacent California: (1) biologic, (2) geomorphic, (3) hydrologic (including surface and subsurface) and (4) pedologic/diagenetic. Specific examples that correspond to the four categories illustrate the broad range of complex natural processes the are affected by climatic change. These responses dictate the potential effects of climatic change on contaminant transport, effects that are being examined by existing and planned environmental-restoration and waste-management programs within the region. Regulatory requirements for many of these programs include long-term (>10,000-year) waste isolation because of radiologic components. The purpose here is not to be exhaustive in documenting all known natural responses to climatic change in the NTS region, but rather to give a flavor of the scope of interdisciplinary and interrelated fields of Quaternary science that must be considered in evaluating the possible effects of climatic change on long-term environmental programs

  5. Distance effects on regional discriminants along a seismic profile in Northwest Nevada; NPE and nuclear results

    Energy Technology Data Exchange (ETDEWEB)

    McCormack, D.A. [AWE Blacknest, Berkshire (United Kingdom); Priestley, K.F. [Univ. of Cambridge (United Kingdom); Patton, H.J. [Lawrence Livermore National Lab., CA (United States)

    1994-12-31

    To address questions of discriminant transportability, it is important to understand how discriminants based on regional seismic phases are affected by regional variations in velocity structure. To examine this issue, we have recorded two explosions, the nuclear explosion Kinibito and the Non-Proliferation Experiment along a 300 km-long profile through western Nevada. We use these data to investigate the stability with distance of several proposed seismic discriminants. In this study we first estimate the apparent attenuation of the regional phases. We compare attenuation corrected amplitude ratios for P{sub n}/L{sub g} and P{sub g}/L{sub g}, and spectral ratios for P{sub n}, P{sub g}, and L{sub g}, as a function of distance along the profile. We make these comparisons for the vertical component and for the total vector resultant using all three components of motion.

  6. AGRONOMIC MANAGEMENT PRACTICES FOR SUSTAINABILITY: CHARACTERISTICS AND MEASUREMENT IN Agave tequilana Weber IN THE SIERRA DE AMULA REGION, JALISCO

    Directory of Open Access Journals (Sweden)

    Arturo Moreno Hernández

    2010-10-01

    Full Text Available This article qualitative evaluation of the sustainable management in blue agave (Agave tequilana Weber agroecosystems, in Sierra Amula region of the Jalisco state, Mexico. Sixteen sites were evaluated in an altitudinal gradient ranging from 777 to 1345 masl. Six principles considered by Altieri (1999 as the basic elements of a sustainable management of the agroecosystem, were used to construct an Index of Agroecosystem Sustainable Management (IMSA. Four levels of this index were identified: values lower than 50 % were considered unsustainable management, 51 to 66.6 % scarcely sustainable management, 66.7 to 83.2 % mediumly sustainable management and 83.3 to 100 % highly sustainable management. Of the 16 sites evaluated, two were classified as unsustainable management, six was scarcely sustainable management, five as medially sustainable management and three as highly sustainable management.

  7. A hydrogeologic map of the Death Valley region, Nevada, and California, developed using GIS techniques

    International Nuclear Information System (INIS)

    Faunt, C.C.; D'Agnese, F.A.; Turner, A.K.

    1997-01-01

    In support of Yucca Mountain site characterization studies, a hydrogeologic framework was developed, and a hydrogeologic map was constructed for the Death Valley region. The region, covering approximately 100,000 km 2 along the Nevada-California border near Las Vegas, is characterized by isolated mountain ranges juxtaposed against broad, alluvium-filled valleys. Geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. The regional ground-water flow system can best be described as a series of connected intermontane basins in which ground-water flow occurs in basin-fill deposits, carbonate rocks, clastic rocks, and volcanic rocks. Previous investigations have developed more site-specific hydrogeologic relationships; however, few have described all the lithologies within the Death Valley regional ground-water flow system. Information required to characterize the hydrogeologic units in the region was obtained from regional geologic maps and reports. Map data were digitized from regional geologic maps and combined into a composite map using a geographic information system. This map was simplified to show 10 laterally extensive hydrogeologic units with distinct hydrologic properties. The hydraulic conductivity values for the hydrogeologic units range over 15 orders of magnitude due to the variability in burial depth and degree of fracturing

  8. 76 FR 34034 - Newspapers Used for Publication of Legal Notices by the Intermountain Region; Utah, Idaho, Nevada...

    Science.gov (United States)

    2011-06-10

    ... Press Humboldt-Toiyabe Forest Supervisor decisions for the Toiyabe portion: Reno Gazette-Journal Austin... decisions affecting National Forests in Nevada: Reno Gazette-Journal Regional Forester decisions affecting... for the Caribou portion: Idaho State Journal Caribou-Targhee Forest Supervisor decisions for the...

  9. 77 FR 33703 - Newspapers Used for Publication of Legal Notices by the Intermountain Region; Utah, Idaho, Nevada...

    Science.gov (United States)

    2012-06-07

    ... Press Humboldt-Toiyabe Forest Supervisor decisions for the Toiyabe portion: Reno Gazette-Journal Austin... Forester decisions affecting National Forests in Nevada: Reno Gazette-Journal Regional Forester decisions... for the Caribou portion: Idaho State Journal Caribou-Targhee Forest Supervisor decisions for the...

  10. 78 FR 33799 - Newspapers Used for Publication of Legal Notices by the Intermountain Region; Utah, Idaho, Nevada...

    Science.gov (United States)

    2013-06-05

    ... Forest Supervisor decisions for the Toiyabe portion: Reno Gazette-Journal Austin District Ranger... affecting National Forests in Nevada: Reno Gazette-Journal Regional Forester decisions affecting National... portion: Idaho State Journal Caribou-Targhee Forest Supervisor decisions for the Targhee portion: Post...

  11. Characterization of Quaternary and suspected Quaternary faults, regional studies, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.E.; Bucknam, R.C.; Crone, A.J.; Haller, K.M.; Machette, M.N.; Personius, S.F.; Barnhard, T.P.; Cecil, M.J.; Dart, R.L.

    1995-12-31

    This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies that resulted in the identification of 51 relevant and potentially relevant individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. Geologic data used to characterize the regional faults and fault zones as relevant or potentially relevant seismic sources includes age and displacement information, maximum fault lengths, and minimum distances between the fault and the Yucca Mountain site. For many of the regional faults, no paleoseismic field studies have previously been conducted, and age and displacement data are sparse to nonexistent. In November 1994, the Branch of Earthquake and Landslide Hazards entered into two Memoranda of Agreement with the Yucca Mountain Project Branch to conduct field reconnaissance, analysis, and interpretation of six relevant and six potentially relevant regional faults. This report describes the results of study of those faults exclusive of those in the Pahrump-Stewart Valley-Ash Meadows-Amargosa Valley areas. We also include results of a cursory study of faults on the west flank of the Specter Range and in the northern part of the Last Chance Range. A four-phase strategy was implemented for the field study.

  12. Regional and Seasonal Diet of the Western Burrowing Owl in South-Central Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Derek B. Hall, Paul D. Greger, Jeffrey R. Rosier

    2009-04-01

    We examined diets of Western Burrowing Owls (Athene cunicularia hypugaea) based on contents of pellets and large prey remains collected year-round at burrows in each of the 3 regions in south central Nevada (Mojave Desert, Great Basin Desert, and Transition region). The most common prey items, based on percent frequency of occurrence, were crickets and grasshoppers, beetles, rodents, sun spiders, and scorpions. The most common vertebrate prey was kangaroo rats (Dipodomys spp.). True bugs (Hemiptera), scorpions, and western harvest mice (Reithrodontomys megalotis) occurred most frequently in pellets from the Great Basin Desert region. Kangaroo rats (Dipodomys spp.) and pocket mice (Perognathinae) were the most important vertebrate prey items in the Transition and Mojave Desert regions, respectively. Frequency of occurrence of any invertebrate prey was high (>80%) in samples year-round but dropped in winter samples, with scorpions and sun spiders exhibiting the steepest declines. Frequency of occurrence of any vertebrate prey peaked in spring samples, was intermediate for winter and summer samples, and was lowest in fall samples. With the possible exception of selecting for western harvest mice in the Great Basin Desert region, Western Burrowing Owls in our study appeared to be opportunistic foragers with a generalist feeding strategy.

  13. Eficiencia de tres atrayentes alimenticios para la captura de Rhagoletis zoqui Bush, 1966 (Díptera: Tephritidae) y caracterización del sistema de producción del nogal de castilla (Juglans regia L.) en la Sierra Nevada de Puebla.

    OpenAIRE

    Aparicio del Moral, Yahana Michelle

    2014-01-01

    La mosca de la fruta Rhagoletis zoqui Bush, 1966 (Diptera: Tephritidae), es un insecto plaga asociado al nogal de Castilla (Juglans regia L.) que ocasiona pérdidas a los productores nogaleros en la Sierra Nevada de Puebla. En los últimos años se han incrementado las poblaciones de este insecto provocando daños importantes al fruto. No se dispone de información científica sobre los aspectos básicos para el control de este insecto en la región. En este trabajo, se evaluaron 3 atrayentes alimen...

  14. Array analysis of regional Pn and Pg wavefields from the Nevada Test Site

    International Nuclear Information System (INIS)

    Leonard, M.A.

    1991-06-01

    Small-aperture high-frequency seismic arrays with dimensions of a few kilometers or less, can improve our ability to seismically monitor compliance with a low-yield Threshold Test Ban Treaty. This work studies the characteristics and effectiveness of array processing of the regional Pn and Pg wavefields generated by underground nuclear explosions at the Nevada Test Site. Waveform data from the explosion HARDIN (m b = 5.5) is recorded at a temporary 12-element, 3-component, 1.5 km-aperture array sited in an area of northern Nevada. The explosions VILLE (m b = 4.4) and SALUT (m b = 5.5) are recorded at two arrays sited in the Mojave desert, one a 96-element vertical-component 7 km-aperture array and the other a 155-element vertical-component 4 km-aperture array. Among the mean spectra for the m b = 5.5 events there are significant differences in low-frequency spectral amplitudes between array sites. The spectra become nearly identical beyond about 6 Hz. Spectral ratios are used to examine seismic source properties and the partitioning of energy between Pn and Pg. Frequency-wavenumber analysis at the 12-element array is used to obtain estimates of signal gain, phase velocity, and source azimuth. This analysis reveals frequency-dependent biases in velocity and azimuth of the coherent Pn and Pg arrivals. Signal correlation, the principal factor governing array performance, is examined in terms of spatial coherence estimates. The coherence is found to vary between the three sites. In all cases the coherence of Pn is greater than that for Pg. 81 refs., 92 figs., 5 tabs

  15. Array analysis of regional Pn and Pg wavefields from the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, M.A. (California Univ., Berkeley, CA (United States). Dept. of Geology and Geophysics Lawrence Berkeley Lab., CA (United States))

    1991-06-01

    Small-aperture high-frequency seismic arrays with dimensions of a few kilometers or less, can improve our ability to seismically monitor compliance with a low-yield Threshold Test Ban Treaty. This work studies the characteristics and effectiveness of array processing of the regional Pn and Pg wavefields generated by underground nuclear explosions at the Nevada Test Site. Waveform data from the explosion HARDIN (m{sub b} = 5.5) is recorded at a temporary 12-element, 3-component, 1.5 km-aperture array sited in an area of northern Nevada. The explosions VILLE (m{sub b} = 4.4) and SALUT (m{sub b} = 5.5) are recorded at two arrays sited in the Mojave desert, one a 96-element vertical-component 7 km-aperture array and the other a 155-element vertical-component 4 km-aperture array. Among the mean spectra for the m{sub b} = 5.5 events there are significant differences in low-frequency spectral amplitudes between array sites. The spectra become nearly identical beyond about 6 Hz. Spectral ratios are used to examine seismic source properties and the partitioning of energy between Pn and Pg. Frequency-wavenumber analysis at the 12-element array is used to obtain estimates of signal gain, phase velocity, and source azimuth. This analysis reveals frequency-dependent biases in velocity and azimuth of the coherent Pn and Pg arrivals. Signal correlation, the principal factor governing array performance, is examined in terms of spatial coherence estimates. The coherence is found to vary between the three sites. In all cases the coherence of Pn is greater than that for Pg. 81 refs., 92 figs., 5 tabs.

  16. The role of volatile-saturation and adiabatic ascent of moderately hydrous melts on the formation of orbicules and comb layers in shallow subvolcanic conduits (Fisher Lake, Sierra Nevada).

    Science.gov (United States)

    McCarthy, A. J.; Müntener, O.

    2016-12-01

    Orbicules and comb layers are enigmatic features found sparsely distributed along plutonic contacts in a wide range of igneous environments. We provide new insights into the mechanisms responsible for the formation of these features by studying the spatial distribution, mineralogy and geochemistry of comb layers and orbicules from the Northern Sierra Nevada, Fisher Lake (USA). Over a range of studied comb textured layering, we show that the large majority of comb layers are cumulates formed by the initiation of plagioclase growth as a comb textured mineral. Plagioclase fractionation is followed by pyroxenes + oxides fractionation. Continuous crystal fractionation and conductive cooling from the host rock leads to amphibole saturation and the formation of late stage comb textured amphibole, leading to the formation of plagioclase- and plagioclase-amphibole comb textures. The lack of amphibole comb textures on orbicule rims as opposed to their widespread occurrence in comb layers, suggests that the presence of a thermal gradient plays an important role in diversifying comb textures. We propose that comb layers and orbicules are unique features which are controlled by the volatile content of ascending melts and ascent mechanisms. Thermodynamic calculations indicate that near-adiabatic decompression of water-undersaturated melts (ca. 4wt% H2O) through the crust will lead to superheating and dissolution of pre-existing minerals. Upon saturation of volatiles at shallow depth, degassing-induced undercooling of the decompressing melt will trigger heterogeneous nucleation of plagioclase on host rocks and remobilized xenoliths. The rarity of orbicules and comb layers in volcanic and plutonic rocks worldwide suggests that adiabatic decompression of moderately hydrous melts leading to superheating is a rare phenomena, with most arc melts ascending and cooling in small reservoirs throughout the crust, prior to emplacement at shallow depth as crystal-bearing magmas.

  17. Abundancia relativa y uso de microhábitat de la rana Geobatrachus walkeri (Anura: Strabomantidae en dos hábitats en Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Vera Martínez Baños

    2011-06-01

    Full Text Available La rana Geobatrachus walkeri pertenece a un género monotípico y endémico del área de San Lorenzo, Sierra Nevada de Santa Marta, Colombia. La especie habita en el bosque secundario natural y en una plantación de pino (dominada por Pinus patula. Para comparar la abundancia relativa y el uso del microhábitat en estos dos hábitat y durante los períodos de máxima y mínima precipitación, se distribuyeron aleatoriamente 30 cuadrantes en cada bosque sobre los que se registraron el número de individuos y los microhábitats ocupados. Además se reconocieron otros aspectos de la historia natural mediante muestreo por encuentros casuales (VES, se incluye en los dos hábitats áreas no muestreadas por los cuadrantes. La mayor abundancia de ranas se obtuvo en la plantación de pino y durante la época de lluvias. El microhábitat más usado fue la hojarasca de pino. Geobatrachus walkeri es una especie exitosa en las plantaciones de pino, asociada permanentemente a su hojarasca en donde parece desarrollar todo su ciclo de vida. Las claras modificaciones derivadas de la introducción de las plantaciones de pino en el suelo y el agua, parecen no haber afectado la supervivencia y mantenimiento exitoso de esta especie categorizada como en peligro de extinción.

  18. Demographic patterns of sedentary and non-sedentary populations: Jesuit missions in lowland South America and Franciscan Missions in the Sierra Gorda Region of Mexico

    Directory of Open Access Journals (Sweden)

    Robert H. Jackson

    2017-11-01

    Full Text Available This article discusses demographic patterns on Jesuit missions in lowlandSouth America (Chiquitos, Guaraní and the Sierra Gorda region of Mexico, including the effects of epidemics of highly contagious diseases such as smallpox and measles. It examines the differences in the demographic profile of sedentary and non-sedentary indigenous groups, as well as other factors that determined demographic patterns. It concludes that there were meaningful differences in demographic patterns.

  19. Source analysis using regional empirical Green's functions: The 2008 Wells, Nevada, earthquake

    Science.gov (United States)

    Mendoza, C.; Hartzell, S.

    2009-01-01

    We invert three-component, regional broadband waveforms recorded for the 21 February 2008 Wells, Nevada, earthquake using a finite-fault methodology that prescribes subfault responses using eight MW∼4 aftershocks as empirical Green's functions (EGFs) distributed within a 20-km by 21.6-km fault area. The inversion identifies a seismic moment of 6.2 x 1024 dyne-cm (5.8 MW) with slip concentrated in a compact 6.5-km by 4-km region updip from the hypocenter. The peak slip within this localized area is 88 cm and the stress drop is 72 bars, which is higher than expected for Basin and Range normal faults in the western United States. The EGF approach yields excellent fits to the complex regional waveforms, accounting for strong variations in wave propagation and site effects. This suggests that the procedure is useful for studying moderate-size earthquakes with limited teleseismic or strong-motion data and for examining uncertainties in slip models obtained using theoretical Green's functions.

  20. [Geographic distribution of birds in the Sierra Madre Oriental of San Luis Potosi, Mexico: a regional analysis of conservation status].

    Science.gov (United States)

    Sahagún Sánchez, Francisco Javier; Navarro, Jaime Castro; Reyes Hernández, Humberto

    2013-06-01

    The Sierra Madre Oriental region in the mexican state of San Luis Potosi is a relevant place for bird conservation at a country level. Therefore the main goal of this study was to analyze the geographic patterns of distribution and the conservation current state of the birds, to support the needs to expand the conservation areas in the future. Data was collected from various databases of zoological museums and collections, and field sampling methods conducted from January 2009 to May 2011. Potential distributions were modeled for 284 species using GARP software and then a map was developed to determine areas with favorable environmental characteristics for the distribution of species richness. Finally, the importance of conservation areas for the potential distribution of birds in the region was evaluated. A total of 359 species were recorded of which 71.4% are permanent residents, 19% are winter migrants and 4% are summer residents. From this total, 41 species were endemic, 47 were species at risk and 149 were neotropical migrants. The largest species richness correspond to oak forests, cloud forests, and tropical moist forests located at altitudes from 100m to 1 500m. Their potential distribution was concentrated towards the center and Southeast of the study area. Only 10% of areas with a high potential conservation was included in areas of priority for bird conservation (AICA) and just 3% of all potential areas were under some governmental category of protection. However, no conservation area has a management plan currently applied and monitored. The information generated is important for the development of management proposals for birds conservation in the region.

  1. REGIONAL HYDROLOGY OF THE NOPAL 1 SITE, SIERRA PENA BLANCA, CHIHUAHUA, MEXICO

    Energy Technology Data Exchange (ETDEWEB)

    J.A. Rodriguez-Pineda; P. Goodell; P. Dobson; J. Walton; R. Olver; R. de la Garza; S. Harder

    2005-10-01

    The objectives of this report are: (1) Determine the main source of the groundwater (GW) found within the DOE wells (PB-1, PB-2, and PB-3); and (2) Determine whether the Nopal I GW has any relationship to the connectivity between the regional Encinillas Aquifer to the west and the El Cuervo Aquifer to the east.

  2. Transporte de materia orgánica a lo largo de un río tropical de montaña en la Sierra Nevada de Santa Marta (Colombia

    Directory of Open Access Journals (Sweden)

    Cesar Enrique Tamaris Turizo

    2015-09-01

    Full Text Available En los ríos tropicales, la materia orgánica es la principal fuente de energía para las comunidades que allí habitan. Las principales proporciones de materia orgánica se encuentra la materia orgánica particulada gruesa (MOPG y  la materia orgánica particulada fina (MOPF. Por lo anterior, en este trabajo se evaluó el transporte de la MOPG,  la MOPF y su relación con algunas variables físicas y químicas en tres tramos de un gradiente altitudinal de los 50 msnm hasta los 1700 msnm durante un ciclo diario en el río Gaira (Sierra Nevada de Santa Marta. Para lo cual se realizaron muestreos mensuales entre los meses de marzo a junio del 2008. Se detectaron diferencias significativas en la deriva de MOPG entre las estaciones, siendo la estación 2 (parte media durante el primer muestreo, la que registró los valores más altos reportados para todo el estudio (474 kg m-3 y la estación 3 mostró la menor biomasa derivante (0,26 kg m-3. La MOPF registró valores similares durante todos los muestreos (0,58 – 6,34 g m-3. Sin embargo, se detectaron diferencias significativas en los muestreos tres y cuatro. Con el aumento de las lluvias, descendió el transporte de  MOPG. Una relación inversa entre la velocidad del agua y el transporte de MOPG (rs = -0,70; n = 12; p < 0,05 se registró, mientras que la MOPF, presentó valores constantes. Los resultados de este trabajo coinciden parcialmente con lo registrado en la literatura, lo cual indica que las dinámicas de transporte de MO están relacionadas con las variaciones ambientales locales.

  3. Wildland fire management and air quality in the southern Sierra Nevada: using the Lion Fire as a case study with a multi-year perspective on PM(2.5) impacts and fire policy.

    Science.gov (United States)

    Schweizer, Don; Cisneros, Ricardo

    2014-11-01

    allow additional burning in an area with severe anthropogenic air pollution and where frequent widespread fire is both beneficial and inevitable. The more extensive air quality impacts documented with large high intensity fire may be averted by embracing the use of fire to prevent unwanted high intensity burns. A widespread increase in the use of fire for ecological benefit may provide the resiliency needed in Sierra Nevada forests as well as be the most beneficial to public health through the reduction of single dose exposure to smoke and limiting impacts spatially. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. MESOZOIC MAGMATISM IN EAST URUGUAY: PETROLOGICAL CONSTRAINTS RELATED TO THE SIERRA SAN MIGUEL REGION

    Directory of Open Access Journals (Sweden)

    Conti Bruno

    2009-07-01

    Full Text Available This work presents new results of a detailed geological and structural investigation focusing the easternmost Uruguayan Mesozoic magmatic occurrences related to the south Atlantic opening. Lithological descriptions, their stratigraphic relationships and complimentary lithochemical characterizations carried out in the San Miguel region (East Uruguay are presented. Three volcanic/sub-volcanic units have been recognized. The felsic volcanic association is composed by rhyolitic - dacitic flows, mainly with porphyritic textures and sub-alkalinenature and related pyroclastic rocks. The felsic sub-volcanic association is characterized by granophyres of about 25 km2 of exposed area, cross- cut by mafic and felsic dykes. Finally, a mafic association has been identified characterized by dykes and a small intrusion of gabbroic composition.All these units are Mesozoic in age (130 - 127 Ma and according to their chemical nature they correspond tosub-alkaline to weak peralkaline magmas.

  5. Calibration and validation of the relative differenced Normalized Burn Ratio (RdNBR) to three measures of fire severity in the Sierra Nevada and Klamath Mountains, California, USA

    Science.gov (United States)

    Miller, J.D.; Knapp, E.E.; Key, C.H.; Skinner, C.N.; Isbell, C.J.; Creasy, R.M.; Sherlock, J.W.

    2009-01-01

    Multispectral satellite data have become a common tool used in the mapping of wildland fire effects. Fire severity, defined as the degree to which a site has been altered, is often the variable mapped. The Normalized Burn Ratio (NBR) used in an absolute difference change detection protocol (dNBR), has become the remote sensing method of choice for US Federal land management agencies to map fire severity due to wildland fire. However, absolute differenced vegetation indices are correlated to the pre-fire chlorophyll content of the vegetation occurring within the fire perimeter. Normalizing dNBR to produce a relativized dNBR (RdNBR) removes the biasing effect of the pre-fire condition. Employing RdNBR hypothetically allows creating categorical classifications using the same thresholds for fires occurring in similar vegetation types without acquiring additional calibration field data on each fire. In this paper we tested this hypothesis by developing thresholds on random training datasets, and then comparing accuracies for (1) fires that occurred within the same geographic region as the training dataset and in similar vegetation, and (2) fires from a different geographic region that is climatically and floristically similar to the training dataset region but supports more complex vegetation structure. We additionally compared map accuracies for three measures of fire severity: the composite burn index (CBI), percent change in tree canopy cover, and percent change in tree basal area. User's and producer's accuracies were highest for the most severe categories, ranging from 70.7% to 89.1%. Accuracies of the moderate fire severity category for measures describing effects only to trees (percent change in canopy cover and basal area) indicated that the classifications were generally not much better than random. Accuracies of the moderate category for the CBI classifications were somewhat better, averaging in the 50%-60% range. These results underscore the difficulty in

  6. 77 FR 25660 - State of Nevada; Regional Haze State and Federal Implementation Plans; BART Determination for...

    Science.gov (United States)

    2012-05-01

    ...), EPA announced a public hearing in Ron Dalley Theater at the Moapa Valley Empowerment High School on... 18, 2012, EPA announced a public hearing in Ron Dalley Theater at the Moapa Valley Empowerment High School on 2400 St. Joseph Street in Overton, Nevada from 6:30 p.m. to 8:30 p.m. on May 3, 2012, with an...

  7. The diffuse seismicity of the Sierra Nevada of Santa Marta, the Perijá Range, and south of the La Guajira peninsula, Colombia and Venezuela: Result of the convergence between Caribbean plate and the South American margin during the Late Neogene?

    Science.gov (United States)

    Chicangana, G.; Pedraza, P.; Mora-paez, H.; Ordonez Aristizabal, C. O.; Vargas-Jimenez, C. A.; Kammer, A.

    2012-12-01

    A diffuse low deep microseismicity located overall between the Guajira peninsula and the Sierra Nevada de Santa Marta (SNSM) was registered with the recent installation (2008 to Present) of three seismological stations in northeastern Colombia by the Colombian Seismological Network (RSNC), but mainly with the Uribia station in (the) central region of La Guajira peninsula, The microseismicity is characterized by a great population of events with 1.2 Oca fault because with the GPS displacement analysis, neotectonics evidence found in faults traces associated to the Oca fault and the historical earthquake that affected the Colombian city of Santa Marta in 1834, lead us to conclude this. This is a big cortical fault that sets the limit between La Guajira peninsula and the SNSM. Its cortical characteristics were verified from geological data together with gravimetric and seismic exploration. The SNSM limits toward the southeast with the Cesar - Ranchería basin, and this basin in turn limits with the Perijá Range that is localized in the Colombia - Venezuela border. The SNSM, Cesar - Ranchería basin and Perijá Range limit toward the southwest with the Bucaramanga - Santa Marta fault (BSMF), the Oca fault toward the north, and Perijá - El Tigre fault toward the southeast defining a pyramidal orogenic complex. Using remote sensing images data with geological and regional geophysical information, we proposed that this orogenic complex was originated as a result of the Panama arc with the northwestern South America accretion. The final adjustment of the Caribbean plate (CP) between North America and South America during the Late Neogene produced the big cortical faults systems activation like Oca - Moron - El Pilar in Colombia and Venezuela toward the south of the Caribbean Plate (CP), and Motegua - Walton - Enriquillo - Plantain Garden toward the north of the CP. This situation was originated of a new subduction development of the Nazca - Cocos plates toward the south

  8. Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

    Science.gov (United States)

    Rowley, Peter D.; Dixon, Gary L.; Watrus , James M.; Burns, Andrews G.; Mankinen, Edward A.; McKee, Edwin H.; Pari, Keith T.; Ekren, E. Bartlett; Patrick , William G.; Comer, John B.; Inkenbrandt, Paul C.; Krahulec, K.A.; Pinnell, Michael L.

    2016-01-01

    The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle

  9. The vectoral role of several blackfly species (Diptera: Simuliidae) in relation to human onchocerciasis in the Sierra Parima and Upper Orinoco regions of Venezuela.

    Science.gov (United States)

    Basáñez, M G; Yarzábal, L; Takaoka, H; Suzuki, H; Noda, S; Tada, I

    1988-12-01

    Experimental and natural infections with Onchocerca volvulus were studied in several anthropophilic blackfly species present in the endemic area of the Upper Orinoco region of Venezuela. When fed on four different Yanomami volunteers in the Sierra Parima, the total infection rate was 31.4% for Simulium guianense in comparison with 7.5% for S. limbatum. The proportion of ingested microfilariae that entered the thorax during the first 24 hours and completed development to the infective stage was also much lower in the latter than in the former species. There was no larval development of O. volvulus in S. antillarum, but one female harboured in its head six infective larvae of a zoonotic filaria. When S. oyapokense s.l. was fed on an infected volunteer in the Upper Orinoco most flies ingested few microfilariae, and further development reached only the L1 stage. Natural infection and infectivity rates for S. guianense in two localities of the Sierra Parima were 0.2-4.0% and 1.3-10.2%, respectively, more than 50% of the L3 larvae being in the head. The corresponding data for S. oyapockense s.l. in the Upper Orinoco were 0.1-0.5%, although the only L3 larva found did not correspond to O. volvulus. It is suggested that S. guianense is the main vector of onchocerciasis in the Sierra Parima and that S. limbatum could play a secondary role. Simulium oyapockense s.l. replaces them in the Upper Orinoco and may maintain a degree of transmission, but its epidemiological importance remains to be assessed.

  10. Using hydrological modelling for a preliminary assessment of under-catch of precipitation in some Alpine Catchments of Sierra Nevada (Spain). Sensitivity to different conceptual approaches and spatio-temporal scale

    Science.gov (United States)

    Jimeno-Saez, Patricia; Pulido-Velazquez, David; Pegalajar-Cuellar, Manuel; Collados-Lara, Antonio-Juan; Pardo-Iguzquiza, Eulogio

    2017-04-01

    Precipitation (P) measurements show important biases due to under-catch, especially in windy conditions. Gauges modify the wind fields, producing important under-catch in solid P. In this work we intent to perform a global assessment of the under-catch phenomenon in some alpine catchments of Sierra Nevada Mountain Range (Spain) by using different conceptual hydrological models. They are based on the available information about daily natural streamflow and daily fields of P and temperature (T) in each catchment. We want to analyse long time periods (more than 20 years at daily scale) in order to obtain conclusions taking into account the stochastic behaviour of the natural streamflow and P and T variables. The natural streamflowin each basin has been obtained from the streamflow measurements in the gauges by making some simple mathematical operations to eliminate the anthropic influences. The daily climatic fieldswere estimated with spatial resolution of 1kmx1km by applying geostatistic techniques using data coming from 119climatic gauges existing in the area.We have considered to model options: Monthly and yearly variogram to characterize the spatial data correlation. The Elevation has been considered as secondary variable for the estimation. The analysis of the experimental data showed a linear relationhip between mean T and elevation. Therefore, we decided to apply a kriging with linear external drift to estimate the P and T fields. The mean daily P data show a quadratic relationship with the elevation. Different hypothesis have been considered to approach these P fields by applying kriging with linear drift, with quadratic drift, and regression kriging. A cross-validation analysis showed that the best approximation to the data is obtained with the kriging with linear drift. The P and T fields obtained with this technique were employed to feed different hydrological models in which different conceptual approaches of the hydrological processes related with the

  11. Gardening guide for high-desert urban landscapes of Great Basin regions in Nevada and Utah

    Science.gov (United States)

    Heidi Kratsch; Rick Heflebower

    2013-01-01

    Some Great Basin urban areas in Utah and Nevada exhibit climatic conditions that make it difficult for all but the toughest landscape plants to thrive without providing supplemental water. These areas are found at elevations from 4,000 feet to 6,000 feet in USDA cold-hardiness zones 6 and 7. Soils are often poor and gravelly, containing less than 1 percent organic...

  12. Sensitivity study on the parameters of the regional hydrology model for the Nevada nuclear waste storage investigations

    International Nuclear Information System (INIS)

    Iman, R.L.; Davenport, J.M.; Waddell, R.K.; Stephens, H.P.; Leap, D.I.

    1979-01-01

    Statistical methodology has been applied to the investigation of the regional hydrologic systems of a large area encompassing the Nevada Test Site (NTS) as a part of the overall evaluation of the NTS for deep geologic disposal of nuclear waste. Statistical techniques including Latin hypercube sampling were used to perform a sensitivity analysis on a two-dimensional finite-element code of 16 geohydrologic zones used to model the regional ground-water flow system. The Latin hypercube sample has been modified to include correlations between corresponding variables from zone to zone. From the results of sensitivity analysis it was found that: (1) the ranking of the relative importance of input variables between locations within the same geohydrologic zone were similar, but not identical; and (2) inclusion of a correlation structure for input variables had a significant effect on the ranking of their relative importance. The significance of these results is discussed with respect to the hydrology of the region

  13. Riparian Birds - Sierra Nevada Foothill [ds303

    Data.gov (United States)

    California Natural Resource Agency — These data are summary statistics of abundances of birds counted within 100-m radius circles with 10-minute point counts at multiple sample points along 36 randomly...

  14. Plant endemism in the Sierras of Córdoba and San Luis (Argentina): understanding links between phylogeny and regional biogeographical patterns1

    Science.gov (United States)

    Chiapella, Jorge O.; Demaio, Pablo H.

    2015-01-01

    Abstract We compiled a checklist with all known endemic plants occurring in the Sierras of Córdoba and San Luis, an isolated mountainous range located in central Argentina. In order to obtain a better understanding of the evolutionary history, relationships and age of the regional flora, we gathered basic information on the biogeographical and floristic affinities of the endemics, and documented the inclusion of each taxon in molecular phylogenies. We listed 89 taxa (including 69 species and 20 infraspecific taxa) belonging to 53 genera and 29 families. The endemics are not distributed evenly, being more abundant in the lower than in the middle and upper vegetation belts. Thirty-two genera (60.3%) have been included in phylogenetic analyses, but only ten (18.8%) included local endemic taxa. A total of 28 endemic taxa of the Sierras CSL have a clear relationship with a widespread species of the same genus, or with one found close to the area. Available phylogenies for some taxa show divergence times between 7.0 – 1.8 Ma; all endemic taxa are most probably neoendemics sensu Stebbins and Major. Our analysis was specifically aimed at a particular geographic area, but the approach of analyzing phylogenetic patterns together with floristic or biogeographical relationships of the endemic taxa of an area, delimited by clear geomorphological features, could reveal evolutionary trends shaping the area. PMID:25878555

  15. Plant endemism in the Sierras of Córdoba and San Luis (Argentina): understanding links between phylogeny and regional biogeographical patterns.

    Science.gov (United States)

    Chiapella, Jorge O; Demaio, Pablo H

    2015-01-01

    We compiled a checklist with all known endemic plants occurring in the Sierras of Córdoba and San Luis, an isolated mountainous range located in central Argentina. In order to obtain a better understanding of the evolutionary history, relationships and age of the regional flora, we gathered basic information on the biogeographical and floristic affinities of the endemics, and documented the inclusion of each taxon in molecular phylogenies. We listed 89 taxa (including 69 species and 20 infraspecific taxa) belonging to 53 genera and 29 families. The endemics are not distributed evenly, being more abundant in the lower than in the middle and upper vegetation belts. Thirty-two genera (60.3%) have been included in phylogenetic analyses, but only ten (18.8%) included local endemic taxa. A total of 28 endemic taxa of the Sierras CSL have a clear relationship with a widespread species of the same genus, or with one found close to the area. Available phylogenies for some taxa show divergence times between 7.0 - 1.8 Ma; all endemic taxa are most probably neoendemics sensu Stebbins and Major. Our analysis was specifically aimed at a particular geographic area, but the approach of analyzing phylogenetic patterns together with floristic or biogeographical relationships of the endemic taxa of an area, delimited by clear geomorphological features, could reveal evolutionary trends shaping the area.

  16. Does the Walker Lane extend through the Nevada test site region?

    International Nuclear Information System (INIS)

    Fridrich, C.; O'Leary, D.

    1993-01-01

    The southeastern terminus of the Walker Lane is poorly defined and poorly understood. Recent work in and around the Nevada Test Site (NTS) suggests the presence of a structural zone that may be an extension of the Walker Lane, and that may be continuous with the Las Vegas valley shear zone farther to the southeast. Unlike the Walker Lane, large through-going strike-slip faults have not been found in the NTS zone. Instead, the strike-slip faults present are few, are relatively short, commonly consist of diffuse fault zones, are interconnected poorly if at all, and largely appear to represent zones of accommodation between domains in which extension occurred at different times and to different degrees. However, the majority of these right-slip and left-slip faults are northwest-trending and northeast-trending, respectively, suggesting that plate motions may have played a role in the creation of these accommodation zones. An obstacle to understanding the NTS zone is that major ignimbrite sheets and calderas of the southwestern Nevada volcanic field (SNVF) formed in this zone at the height of late Tertiary tectonic activity, possibly burying much of the structural evidence. The NTS zone could represent an intersection of the Walker Lane with another major structural feature, a significant bend in the Walker Lane, or a transtensional tear that localized accommodation structures as well as the prominent late Miocene calderas of the SNVF. Ongoing field work is aimed at determining which of these and competing interpretations is best

  17. Estimates of carbon stored in harvested wood products from United States Forest Service's Sierra Nevada Bio-Regional Assessment Area of the Pacific Southwest Region, 1909-2012

    Science.gov (United States)

    Keith Stockmann; Nathaniel Anderson; Jesse Young; Ken Skog; Sean Healey; Dan Loeffler; Edward Butler; J. Greg Jones; James Morrison

    2014-01-01

    Global forests capture and store significant amounts of carbon through photosynthesis. When carbon is removed from forests through harvest, a portion of the harvested carbon is stored in wood products, often for many decades. The United States Forest Service (USFS) and other agencies are interested in accurately accounting for carbon flux associated with harvested wood...

  18. Investigating the Influence of Regional Stress on Fault and Fracture Permeability at Pahute Mesa, Nevada National Security Site

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Donald M. [Desert Research Inst. (DRI), Reno, NV (United States); Smith, Kenneth D. [Univ. of Nevada, Reno, NV (United States); Parashar, Rishi [Desert Research Inst. (DRI), Reno, NV (United States); Collins, Cheryl [Desert Research Inst. (DRI), Las Vegas, NV (United States); Heintz, Kevin M. [Desert Research Inst. (DRI), Las Vegas, NV (United States)

    2017-05-24

    Regional stress may exert considerable control on the permeability and hydraulic function (i.e., barrier to and/or conduit for fluid flow) of faults and fractures at Pahute Mesa, Nevada National Security Site (NNSS). In-situ measurements of the stress field are sparse in this area, and short period earthquake focal mechanisms are used to delineate principal horizontal stress orientations. Stress field inversion solutions to earthquake focal mechanisms indicate that Pahute Mesa is located within a transtensional faulting regime, represented by oblique slip on steeply dipping normal fault structures, with maximum horizontal stress ranging from N29°E to N63°E and average of N42°E. Average horizontal stress directions are in general agreement with large diameter borehole breakouts from Pahute Mesa analyzed in this study and with stress measurements from other locations on the NNSS.

  19. Hydraulic fracturing stress measurements at Yucca Mountain, Nevada, and relationship to the regional stress field

    International Nuclear Information System (INIS)

    Stock, J.M.; Healy, J.H.; Hickman, S.H.; Zoback, M.D.

    1985-01-01

    Hydraulic fracturing stress measurements and acoustic borehole televiewer logs were run in holes USW G-1 and USW G-2 at Yucca Mountain as part of the Nevada Nuclear Waste Storage Investigations for the U. S. Department of Energy. Eight tests in the saturated zone, at depths from 646 to 1288 m, yielded values of the least horizontal stress S/sub h/ that are considerably lower than the vertical principal stress S/sub v/. In tests for which the greatest horizontal principal stress S/sub H/ could be determined, it was found to be less than S/sub v/, indicating a normal faulting stress regime. The borehole televiewer logs showed the presence of long (in excess of 10 m), vertical, drilling-induced fractures in the first 300 m below the water table. These are believed to form by the propagation of small preexisting cracks under the excess downhole fluid pressures (up to 5.2 MPa) applied during drilling. The presence of these drilling-induced hydrofractures provides further confirmation of the low value of the least horizontal stresses. A least horizontal principal stress direction of N60 0 W--N65 0 W is indicated by the orientation of the drilling-induced hydrofractures (N25 0 E--N30 0 E), and the orientation of stress-induced well bore breakouts in the lower part of USW G-2 (N65 0 W). This direction is in good agreement with indicators of stress direction from elsewhere at the Nevada Test Site. The observed stress magnitudes and directions were examined for the possibility of slip on preexisting faults. Using these data, the Coulomb criterion for frictional sliding suggests that for coefficients of friction close to 0.6, movement on favorably oriented faults could be expected

  20. Alpine Plant Monitoring for Global Climate Change; Analysis of the Four California GLORIA Target Regions

    Science.gov (United States)

    Dennis, A.; Westfall, R. D.; Millar, C. I.

    2007-12-01

    The Global Observation Research Initiative in Alpine Environments (GLORIA) is an international research project with the goal to assess climate-change impacts on vegetation in alpine environments worldwide. Standardized protocols direct selection of each node in the network, called a Target Region (TR), which consists of a set of four geographically proximal mountain summits at elevations extending from treeline to the nival zone. For each summit, GLORIA specifies a rigorous mapping and sampling design for data collection, with re-measurement intervals of five years. Whereas TRs have been installed in six continents, prior to 2004 none was completed in North America. In cooperation with the Consortium for Integrated Climate Research in Western Mountains (CIRMOUNT), California Native Plant Society, and the White Mountain Research Station, four TRs have been installed in California: two in the Sierra Nevada and two in the White Mountains. We present comparative results from analyses of baseline data across these four TRs. The number of species occurring in the northern Sierra (Tahoe) TR was 35 (16 not found in other TRs); in the central Sierra (Dunderberg) TR 65 species were found. In the White Mountains, 54 species were found on the granitic/volcanic soils TR and 46 (19 not found in other TRs) on the dolomitic soils TR. In all, we observed 83 species in the Sierra Nevada range TRs and 75 in the White Mountain TRs. Using a mixed model ANOVA of percent cover from summit-area-sections and quadrat data, we found primary differences to be among mountain ranges. Major soil differences (dolomite versus non-dolomite) also contribute to floristic differentiation. Aspect did not seem to contribute significantly to diversity either among or within target regions. Summit floras in each target region comprised groups of two distinct types of species: those with notably broad elevational ranges and those with narrow elevational ranges. The former we propose to be species that

  1. Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The three study units are located in the Sierra Nevada region of California in parts of Nevada, Placer, El Dorado, Madera, Tulare, and Kern Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board, in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The project was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems used for drinking water. The primary aquifer systems (hereinafter, primary aquifers) for each study unit are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for municipal and community drinking-water supply. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to contamination from the surface. The assessments for the Tahoe-Martis, Central Sierra, and Southern Sierra study units were based on water-quality and ancillary data collected by the USGS from 132 wells in the three study units during 2006 and 2007 and water-quality data reported in the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of the natural and human factors affecting groundwater quality. The assessments characterize untreated groundwater quality, not the quality of treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentrations divided by benchmark concentrations) were used for evaluating groundwater quality for those

  2. Preliminary estimates of spatially distributed net infiltration and recharge for the Death Valley region, Nevada-California

    International Nuclear Information System (INIS)

    Hevesi, J.A.; Flint, A.L.; Flint, L.E.

    2002-01-01

    A three-dimensional ground-water flow model has been developed to evaluate the Death Valley regional flow system, which includes ground water beneath the Nevada Test Site. Estimates of spatially distributed net infiltration and recharge are needed to define upper boundary conditions. This study presents a preliminary application of a conceptual and numerical model of net infiltration. The model was developed in studies at Yucca Mountain, Nevada, which is located in the approximate center of the Death Valley ground-water flow system. The conceptual model describes the effects of precipitation, runoff, evapotranspiration, and redistribution of water in the shallow unsaturated zone on predicted rates of net infiltration; precipitation and soil depth are the two most significant variables. The conceptual model was tested using a preliminary numerical model based on energy- and water-balance calculations. Daily precipitation for 1980 through 1995, averaging 202 millimeters per year over the 39,556 square kilometers area of the ground-water flow model, was input to the numerical model to simulate net infiltration ranging from zero for a soil thickness greater than 6 meters to over 350 millimeters per year for thin soils at high elevations in the Spring Mountains overlying permeable bedrock. Estimated average net infiltration over the entire ground-water flow model domain is 7.8 millimeters per year. To evaluate the application of the net-infiltration model developed on a local scale at Yucca Mountain, to net-infiltration estimates representing the magnitude and distribution of recharge on a regional scale, the net-infiltration results were compared with recharge estimates obtained using empirical methods. Comparison of model results with previous estimates of basinwide recharge suggests that the net-infiltration estimates obtained using this model may overestimate recharge because of uncertainty in modeled precipitation, bedrock permeability, and soil properties for

  3. Death Valley regional ground-water flow system, Nevada and California -- hydrogeologic framework and transient ground-water flow model

    Science.gov (United States)

    Belcher, Wayne R.

    2004-01-01

    A numerical three-dimensional (3D) transient ground-water flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the ground-water flow system and previous less extensive ground-water flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect ground-water flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley Regional Ground-Water Flow System (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the ground-water flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural ground-water discharge occurring through evapotranspiration and spring flow; the history of ground-water pumping from 1913 through 1998; ground-water recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were

  4. Death Valley regional groundwater flow system, Nevada and California-Hydrogeologic framework and transient groundwater flow model

    Science.gov (United States)

    Belcher, Wayne R.; Sweetkind, Donald S.

    2010-01-01

    A numerical three-dimensional (3D) transient groundwater flow model of the Death Valley region was developed by the U.S. Geological Survey for the U.S. Department of Energy programs at the Nevada Test Site and at Yucca Mountain, Nevada. Decades of study of aspects of the groundwater flow system and previous less extensive groundwater flow models were incorporated and reevaluated together with new data to provide greater detail for the complex, digital model. A 3D digital hydrogeologic framework model (HFM) was developed from digital elevation models, geologic maps, borehole information, geologic and hydrogeologic cross sections, and other 3D models to represent the geometry of the hydrogeologic units (HGUs). Structural features, such as faults and fractures, that affect groundwater flow also were added. The HFM represents Precambrian and Paleozoic crystalline and sedimentary rocks, Mesozoic sedimentary rocks, Mesozoic to Cenozoic intrusive rocks, Cenozoic volcanic tuffs and lavas, and late Cenozoic sedimentary deposits of the Death Valley regional groundwater flow system (DVRFS) region in 27 HGUs. Information from a series of investigations was compiled to conceptualize and quantify hydrologic components of the groundwater flow system within the DVRFS model domain and to provide hydraulic-property and head-observation data used in the calibration of the transient-flow model. These studies reevaluated natural groundwater discharge occurring through evapotranspiration (ET) and spring flow; the history of groundwater pumping from 1913 through 1998; groundwater recharge simulated as net infiltration; model boundary inflows and outflows based on regional hydraulic gradients and water budgets of surrounding areas; hydraulic conductivity and its relation to depth; and water levels appropriate for regional simulation of prepumped and pumped conditions within the DVRFS model domain. Simulation results appropriate for the regional extent and scale of the model were provided

  5. Environmental overview of geothermal development: northern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Slemmons, D.B.; Stroh, J.M.; Whitney, R.A. (eds.)

    1980-08-01

    Regional environmental problems and issues associated with geothermal development in northern Nevada are studied to facilitate environmental assessment of potential geothermal resources. The various issues discussed are: environmental geology, seismicity of northern Nevada, hydrology and water quality, air quality, Nevada ecosystems, noise effects, socio-economic impacts, and cultural resources and archeological values. (MHR)

  6. Geothermal direct heat use: market potential/penetration analysis for Federal Region IX (Arizona, California, Hawaii, Nevada)

    Energy Technology Data Exchange (ETDEWEB)

    Powell, W.; Tang, K. (eds.)

    1980-05-01

    A preliminary study was made of the potential for geothermal direct heat use in Arizona, California, Hawaii, and Nevada (Federal Region IX). The analysis for each state was performed by a different team, located in that state. For each state, the study team was asked to: (1) define the resource, based on the latest available data; (2) assess the potential market growth for geothermal energy; and (3) estimate the market penetration, projected to 2020. Each of the four states of interest in this study is unique in its own way. Rather than impose the same assumptions as to growth rates, capture rates, etc. on all of the study teams, each team was asked to use the most appropriate set of assumptions for its state. The results, therefore, should reflect the currently accepted views within each state. The four state reports comprise the main portion of this document. A brief regional overview section was prepared by the Jet Propulsion Laboratory, following completion of the state reports.

  7. Archaeological obsidian from La Sierra Gorda Mexico, by PIXE

    International Nuclear Information System (INIS)

    Juarez-Cossio, D.; Terreros, E.; Quiroz-Moreno, J.; Romero-Sanchez, S.; Calligaro, T.F.; Tenorio, D.; Jimenez-Reyes, M.; Los Rios, M. de

    2009-01-01

    The chemical compositions of 42 obsidian pre-Hispanic artifacts from Tancama and Purisima, both archaeological sites of La Sierra Gorda Valleys, Mexico, were analyzed by PIXE technique. These obsidians came from four sources: Sierra de Pachuca Hidalgo, Paraiso Queretaro, Ucareo Michoacan and mainly from Zacualtipan/Metzquititlan Hidalgo. According to archaeological evidences, La Sierra Gorda valleys participated in commercial exchange with other regional sites, from Classic to Post-classic periods (A.D. 300-1500).

  8. Nevada Southwest Regional Geothermal Development Operations Research Project. Appendix 8 of regional operations research program for development of geothermal energy in the Southwest United States. Final technical report, June 1977--August 1978

    Energy Technology Data Exchange (ETDEWEB)

    Clark, Noel A.; Booth, G. Martin, III; Weber, Dorismae; Helseth, Barbara K.

    1979-01-01

    By the end of the first year of the Southwest Regional Geothermal Project, the Nevada State Team has defined over 300 geothermal sites. Because of the multitude of sites and data, scenarios for this first project-year have been completed for the twenty-six Nevada Geothermal Areas, which include all the specific sites. It is not improbable that fully one-third of the sites will eventually prove to be of high to intermediate temperature (i.e. > 150 C and 90-150 C) resources. Low temperature sites are also prominent, not only in number, but also in their distribution--each of Nevada's 17 counties has several such sites.

  9. La participación como base del turismo comunitario y el manejo de los recursos de uso común. Sendero de Ritakuwas, Sierra Nevada de El Cocuy, Güicán y / o Chita. Boyacá, Colombia

    Directory of Open Access Journals (Sweden)

    Daniel Calderón Ramírez

    2014-11-01

    Full Text Available El objetivo principal de este estudio fue analizar el sendero que conduce al Ritakuwa Blanco, montaña de 5.330 m. s. n. m. ubicada en la Sierra Nevada de El Cocuy, Güicán y / o Chita, como un recurso de uso común (ruc. A través de este ruc se han establecido servicios turísticos y se han dado diferentes formas de participación por parte de las comunidades locales rurales, quienes lo usan y aprovechan. Por tanto, es necesaria una acción colectiva de los usuarios capaz de formular acuerdos o crear instituciones para el autogobierno y el uso sostenible del ruc, con el fin de evitar la tragedia de los bienes comunes2. Los prestadores de servicios turísticos decidieron participar en la planificación del ecoturismo debido a los estímulos y beneficios que pudieran llegar a recibir, como el fortalecimiento de la acción colectiva, la mayor autonomía y autogobierno para la sostenibilidad del sendero, la formalidad en la cadena de valor del turismo y la diversificación de los atractivos turísticos.

  10. Ground magnetic studies along a regional seismic-reflection profile across Bare Mountain, Crater Flat and Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Langenheim, V.E.; Ponce, D.A.

    1995-01-01

    Ground magnetic data were collected along a 26-km-long regional seismic-reflection profile in southwest Nevada that starts in the Amargosa Desert, crosses Bare Mountain, Crater Flat and Yucca Mountain, and ends in Midway Valley. Parallel ground magnetic profiles were also collected about 100 m to either side of the western half of the seismic-reflection line. The magnetic data indicate that the eastern half of Crater Flat is characterized by closely-spaced faulting (1--2 km) in contrast to the western half of Crater Flat. Modeling of the data indicates that the Topopah Spring Tuff is offset about 250 m on the Solitario Canyon fault and about 50 m on the Ghost Dance fault. These estimates of fault offset are consistent with seismic-reflection data and geologic mapping. A broad magnetic high of about 500--600 nT is centered over Crater Flat. Modeling of the magnetic data indicates that the source of this high is not thickening and doming of the Bullfrog Tuff, but more likely lies below the Bullfrog Tuff. Possible source lithologies for this magnetic high include altered argillite of the Eleana Formation, Cretaceous or Tertiary intrusions, and mafic sills

  11. SIERRA-Flux: Measuring Regional Surface Fluxes of Carbon Dioxide, Methane, and Water Vapor from an Unmanned Aircraft System

    Science.gov (United States)

    Fladeland; Yates, Emma Louise; Bui, Thaopaul Van; Dean-Day, Jonathan; Kolyer, Richard

    2011-01-01

    The Eddy-Covariance Method for quantifying surface-atmosphere fluxes is a foundational technique for measuring net ecosystem exchange and validating regional-to-global carbon cycle models. While towers or ships are the most frequent platform for measuring surface-atmosphere exchange, experiments using aircraft for flux measurements have yielded contributions to several large-scale studies including BOREAS, SMACEX, RECAB by providing local-to-regional coverage beyond towers. The low-altitude flight requirements make airborne flux measurements particularly dangerous and well suited for unmanned aircraft.

  12. A Guide for Using the Transient Ground-Water Flow Model of the Death Valley Regional Ground-Water Flow System, Nevada and California

    Energy Technology Data Exchange (ETDEWEB)

    Joan B. Blainey; Claudia C. Faunt, and Mary C. Hill

    2006-05-16

    This report is a guide for executing numerical simulations with the transient ground-water flow model of the Death Valley regional ground-water flow system, Nevada and California using the U.S. Geological Survey modular finite-difference ground-water flow model, MODFLOW-2000. Model inputs, including observations of hydraulic head, discharge, and boundary flows, are summarized. Modification of the DVRFS transient ground-water model is discussed for two common uses of the Death Valley regional ground-water flow system model: predictive pumping scenarios that extend beyond the end of the model simulation period (1998), and model simulations with only steady-state conditions.

  13. Active deformation in the northern Sierra de Valle Fértil, Sierras Pampeanas, Argentina

    Science.gov (United States)

    Ortiz, Gustavo; Alvarado, Patricia; Fosdick, Julie C.; Perucca, Laura; Saez, Mauro; Venerdini, Agostina

    2015-12-01

    The Western Sierras Pampeanas region in the San Juan Province is characterized by thick-skinned deformation with approximately N-S trending ranges of average heights of 2500 m and a high frequency occurrence of seismic activity. Its location to the east of the mainly thin-skinned tectonics of the Argentine Precordillera fold-and-thrust belt suggests that at 30°S, deformation is concentrated in a narrow zone involving these two morphostructural units. In this paper, we present new apatite (U-Th)/He results (AHe) across the northern part of the Sierra de Valle Fértil (around 30°S) and analyze them in a framework of thermochronologic available datasets. We found Pliocene AHe results for Carboniferous and Triassic strata in the northern Sierra de Valle Fértil consistent with the hypothesis of recent cooling and inferred erosional denudation concentrated along the northern end of this mountain range. Our analysis shows that this northern region may have evolved under different conditions than the central part of the Sierra de Valle Fértil. Previous studies have observed AHe ages consistent with Permian through Cretaceous cooling, indicating the middle part of the Sierra de Valle Fértil remained near surface before the Pampean slab subduction flattening process. Those studies also obtained ˜5 My cooling ages in the southern part of the Sierra de Valle Fértil, which are similar to our results in the northern end of the range. Taken together, these results suggest a pattern of young deformation in the northern and southern low elevation ends of the Sierra de Valle Fértil consistent with regions of high seismic activity, and Quaternary active faulting along the western-bounding thrust fault of the Sierra de Valle Fértil.

  14. Effect of faulting on ground-water movement in the Death Valley region, Nevada and California

    International Nuclear Information System (INIS)

    Faunt, C.C.

    1997-01-01

    This study characterizes the hydrogeologic system of the Death Valley region, an area covering approximately 100,000 square kilometers. The study also characterizes the effects of faults on ground-water movement in the Death Valley region by synthesizing crustal stress, fracture mechanics,a nd structural geologic data. The geologic conditions are typical of the Basin and Range Province; a variety of sedimentary and igneous intrusive and extrusive rocks have been subjected to both compressional and extensional deformation. Faulting and associated fracturing is pervasive and greatly affects ground-water flow patterns. Faults may become preferred conduits or barriers to flow depending on whether they are in relative tension, compression, or shear and other factors such as the degree of dislocations of geologic units caused by faulting, the rock types involved, the fault zone materials, and the depth below the surface. The current crustal stress field was combined with fault orientations to predict potential effects of faults on the regional ground-water flow regime. Numerous examples of fault-controlled ground-water flow exist within the study area. Hydrologic data provided an independent method for checking some of the assumptions concerning preferential flow paths. 97 refs., 20 figs., 5 tabs

  15. Regional groundwater modeling of the saturated zone in the vicinity of Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Ahola, M.; Sagar, B.

    1992-10-01

    Results of groundwater modeling of the saturated zone in the vicinity of Yucca Mountain are presented. Both a regional (200 x 200 km) and subregional (50 x 50 km) model were used in the analyses. Simulations were conducted to determine the impact of various disruptive that might take place over the life span of a proposed Yucca Mountain geologic conditions repository on the groundwater flow field, as well as changes in the water-table elevations. These conditions included increases in precipitation and groundwater recharge within the regional model, changes in permeability of existing hydrogeologic barriers, a:nd the vertical intrusion of volcanic dikes at various orientations through the saturated zone. Based on the regional analysis, the rise in the water-table under Yucca Mountain due to various postulated conditions ranged from only a few meters to 275 meters. Results of the subregional model analysis, which was used to simulate intrusive dikes approximately 4 kilometers in length in the vicinity of Yucca Mountain, showed water-table rises ranging from a few meters to as much as 103 meters. Dikes oriented approximately north-south beneath Yucca Mountain produced the highest water-table rises. The conclusions drawn from this analysis are likely to change as more site-specific data become available and as the assumptions in the model are improved

  16. Conserving the Greater Sage-grouse: A social-ecological systems case study from the California-Nevada region

    Science.gov (United States)

    Duvall, Alison L; Metcalf, Alexander L.; Coates, Peter S.

    2016-01-01

    The Endangered Species Act (ESA) continues to serve as one of the most powerful and contested federal legislative mandates for conservation. In the midst of heated debates, researchers, policy makers, and conservation practitioners champion the importance of cooperative conservation and social-ecological systems approaches, which forge partnerships at multiple levels and scales to address complex ecosystem challenges. However, few real-world examples exist to demonstrate how multifaceted collaborations among stakeholders who share a common goal of conserving at-risk species may be nested within a systems framework to achieve social and ecological goals. Here, we present a case study of Greater Sage-grouse (Centrocercus urophasianus) conservation efforts in the “Bi-State” region of California and Nevada, United States. Using key-informant interviews, we explored dimensions and drivers of this landscape-scale conservation effort. Three themes emerged from the interviews, including 1) ESA action was transformed into opportunity for system-wide conservation; 2) a diverse, locally based partnership anchored collaboration and engagement across multiple levels and scales; and 3) best-available science combined with local knowledge led to “certainty of effectiveness and implementation”—the criteria used by the US Fish and Wildlife Service to evaluate conservation efforts when making listing decisions. Ultimately, collaborative conservation through multistakeholder engagement at various levels and scales led to proactive planning and implementation of conservation measures and precluded the need for an ESA listing of the Bi-State population of Greater Sage-grouse. This article presents a potent example of how a systems approach integrating policy, management, and learning can be used to successfully overcome the conflict-laden and “wicked” challenges that surround at-risk species conservation.

  17. Guide to Using Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Ryan Phillip [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Agelastos, Anthony Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Miller, Joel D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Sierra is an engineering mechanics simulation code suite supporting the Nation's Nuclear Weapons mission as well as other customers. It has explicit ties to Sandia National Labs' workfow, including geometry and meshing, design and optimization, and visualization. Dis- tinguishing strengths include "application aware" development, scalability, SQA and V&V, multiple scales, and multi-physics coupling. This document is intended to help new and existing users of Sierra as a user manual and troubleshooting guide.

  18. Guide to Using Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Ryan Phillip; Agelastos, Anthony Michael; Miller, Joel D.

    2017-04-01

    Sierra is an engineering mechanics simulation code suite supporting the Nation's Nuclear Weapons mission as well as other customers. It has explicit ties to Sandia National Labs' workfow, including geometry and meshing, design and optimization, and visualization. Dis- tinguishing strengths include "application aware" development, scalability, SQA and V&V, multiple scales, and multi-physics coupling. This document is intended to help new and existing users of Sierra as a user manual and troubleshooting guide.

  19. Species of conservation concern and environmental stressors: local regional and global effects: Chapter 6 in The Southern Nevada Agency Partnership science and research synthesis: science to support land management in southern Nevada

    Science.gov (United States)

    Ostoja, Steven M.; Brooks, Matthew L.; Chambers, Jeanne C.; Pendleton, Burton

    2013-01-01

    Species conservation has traditionally been based on individual species within the context of their requisite habitat, which is generally defined as the communities and ecosystems deemed necessary for their presence. Conservation decisions are hampered by the fact that environmental stressors that poetically threaten the persistence of species can operate at organizational levels larger than the habitat or home range of a focal species. Resource managers must therefore simultaneously consider local, regional, and/or global scale stressors for effective conservation and management of species of concern. The wide ranging effects associated with global stressors such as climate change may exceed or exacerbate the effects of local or regional stressors, they still need to understand the direct and interactive effects of global stressors and ultimately how they affect the lands they manage. Conservation of species in southern Nevada is further complication by the fact that the region includes one of the largest and fastest growing urban centers in North America. To accomplish the goal of species conservation, resource managers must identify actionable management options that mitigate the effects of local and regional stressor in the context of the effects of global stressors that are beyond their control. Species conservation is typically focused on a subset often referred to as species of conservation concern that have either demonstrated considerable decline or are naturally rare or have limited distributions. Stressors can directly and indirectly impact species in a variety of ways and through a diversity of mechanisms. Some stressors have been more intense in the past (e.g., livestock grazing) whereas other are now only emerging as new stressors (e.g., solar energy development, climate change). The primary stressors affecting southern Nevada ecosystems are listed in table 2.1 and reviewed in detail in Chapter 2. This chapter addresses Dub-goal 1.4 in the SNAP

  20. Digital Elevation Model (DEM) file of topographic elevations for the Death Valley region of southern Nevada and southeastern California processed from US Geological Survey 1-degree Digital Elevation Model data files

    International Nuclear Information System (INIS)

    Turner, A.K.; D'Agnese, F.A.; Faunt, C.C.

    1996-01-01

    Elevation data have been compiled into a digital data base for an ∼100,000-km 2 area of the southern Great Basin, the Death Valley region of southern Nevada, and SE Calif., located between lat 35 degree N, long 115 degree W, and lat 38 degree N, long 118 degree W. This region includes the Nevada Test Site, Yucca Mountain, and adjacent parts of southern Nevada and eastern California and encompasses the Death Valley regional ground-water system. Because digital maps are often useful for applications other than that for which they were originally intended, and because the area corresponds to a region under continuing investigation by several groups, these digital files are being released by USGS

  1. A tale of 10 plutons - Revisited: Age of granitic rocks in the White Mountains, California and Nevada

    Science.gov (United States)

    McKee, E.H.; Conrad, J.E.

    1996-01-01

    40Ar/39Ar incremental heating analysis and conventional K-Ar age determinations on plutonic rocks of the White Mountains define two stages of magmatic emplacement: Late Cretaceous, between ca. 90 Ma and 75 Ma, and Middle-Late Jurassic, between ca. 180 and 140 Ma. The Jurassic stage can be divided into two substages, 180-165 Ma and 150-140 Ma. Thermal effects of the younger plutons on the older granitoids partially to completely reset ages, making it difficult to determine the age of emplacement and cooling of several of the plutons even by 40Ar/39Ar incremental heating analyses. New data together with published ages and regional geochronological synthesis of the Sierra Nevada batholith indicate that regions within the batholith have coherent periods or episodes of magmatic activity. In the White Mountains and Sierra Nevada directly to the west there was little or no activity in Early Jurassic and Early Cretaceous time; magmatism took place during relatively short intervals of 15 m.y. or less in the Middle and Late Jurassic and Late Cretaceous periods. The new K-Ar and 40Ar/39Ar analyses of granitoids from the White Mountains help, but do not completely clarify the complex history of emplacement, cooling, and reheating of the batholith.

  2. Demography of the California spotted owl in the Sierra National Forest and Sequoia/Kings Canyon National Parks

    Science.gov (United States)

    George N. Steger; Thomas E. Munton; Kenneth D. Johnson; Gary P. Eberlein

    2002-01-01

    Nine years (1990–1998) of demographic data on California spotted owls (Strix occidentalis occidentalis) in two study areas on the western slopes of the Sierra Nevada—one in the Sierra National Forest (SNF), the other in Sequoia/Kings Canyon National Parks (SNP)—are summarized. Numbers of territorial owls fluctuated from 85 to 50 in SNF and 80 to 58...

  3. Ecosystem stressors in southern Nevada [Chapter 2] (Executive Summary)

    Science.gov (United States)

    Burton K. Pendleton; Jeanne C. Chambers; Matthew L. Brooks; Steven M. Ostoja

    2013-01-01

    Southern Nevada ecosystems are subject to a number of stressors that range in scope from local to regional to global. At the regional scale, human population growth and related activities constitute a major stressor. Nevada has undergone significant change due to unprecedented population growth and ongoing global change processes. Nevada’s growth rate has been the...

  4. Sistemas de flujo subterráneo regional en el acuífero carbonatado mesozoico de la sierra de Cameros. Sector oriental

    Directory of Open Access Journals (Sweden)

    Martínez Gíl, F. J.

    1997-08-01

    Full Text Available The hydrogeologic conceptual model of the thermal springs of Baños de Fitero (Navarra and Arnedillo (La Rioja is studied. These springs are located in the eastern part of the Cameros Chain, in the contact among the Iberian Chain and the Ebro Basin materials, in the basins of the Alhama and Cidacos rivers respectively. These springs have their origin in regional groundwater flows through the materials of the marine Jurassic (especially of the lower Lías that constitute a karstified carbonate aquifer. The main discharges of this aquifer take place in the contact among these materials -included in the Cameros unit- and the Ebro Basin materials in the points in which the river crosses the cited contact. The annual mean resources have been evaluated in 5.41 hm3/year for the Cidacos river and 3.52 hm3/year in the case of the Alhama river, that include thermal as not thermal contributions. These springs have fixed chemical composition, predominantly characterized by sodium chloride content, associated with high contents in ions, constant and high emergency temperature and low content in tritium, overall indicative of the presence of a regional groundwater flow. In the regional context is evidenced a regional groundwater flow system, from calcium bicarbonate of low mineralization water to calcium-sulphate water and to sodium- chloride, very mineralized and thermal water. The topography and the contrast of permeabilities (aquitard/aquifer imply the existence of local flow systems in the aquitard and a regional system through lower aquifer that acts as «main drain» of the upper materials. The geothermal gradient in the discharge zones is more high than the mean geothermal gradient.Se estudia el funcionamiento hidrogeológico de los manantiales termales de Baños de Fitero (Navarra y Arnedillo (La Rioja, que se ubican en la parte oriental de la Sierra de Cameros, en el contacto entre esta unidad de la Cordillera Ibérica y los materiales terciarios

  5. Aeromagnetic maps of the Colorado River region including the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degrees quadrangles, California, Arizona, and Nevada

    Science.gov (United States)

    Mariano, John; Grauch, V.J.

    1988-01-01

    Aeromagnetic data for the Colorado river region have been compiled as part of the Pacific to Arizona Crustal Experiment (PACE) Project. The data are presented here in a series of six compilations for the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degree quadrangles, California, Arizona, and Nevada, at scales of 1:250,000 and 1:750,000. The scales and map areas are identical to those used by Mariano and others (1986) to display the Bouguer and isotatic residual gravity for this region. Data were compiled separately for the Kingman quadrangle, the Needles quadrangle, and an area covering the Salton Sea quadrangle and part of the El Centro quadrangle.

  6. Nature and origin of the nonsulfide zinc deposits in the Sierra Mojada District, Coahuila, Mexico: constraints from regional geology, petrography, and isotope analyses

    Science.gov (United States)

    Kyle, J. Richard; Ahn, Hyein; Gilg, H. Albert

    2018-02-01

    The Sierra Mojada District comprises multiple types of near-surface mineral concentrations ranging from polymetallic sulfide zones, "nonsulfide Zn" (NSZ) deposits, and a silver-rich Pb carbonate deposit hosted by lower Cretaceous carbonate strata. Hypogene concentrations of Fe-Zn-Pb-Cu-Ag sulfides and sulfosalts are locally preserved and are associated with hydrothermal dolomite and silica. Alteration mineralogy and sulfur isotope data suggest primary Zn-Pb-Ag mineralization from circa 200 °C hydrothermal fluids. The NSZ deposits dominantly consist of smithsonite and hemimorphite associated with local Mn-Fe oxides. The Red Zinc Zone consists of strata-bound zones dominantly of hemimorphite that fills pores in residual and resedimented Fe oxides. The White Zinc Zone shows local dissolution features, including internal sediments interbanded with and cemented by smithsonite. Similar Pb isotopic compositions of smithsonite, hemimorphite, and cerussite to Sierra Mojada galena document that the NSZ deposits originated from polymetallic carbonate-replacement sulfide deposits, with flow of metal-bearing groundwater being controlled by local topography and structural features in this extensional terrane. Oxygen isotope values for Sierra Mojada smithsonite are relatively constant (δ18OVSMOW = 20.9 to 23.3‰) but are unusually low compared to other supergene smithsonites. Using δ18OVSMOW (- 8‰) of modern groundwater at nearby Cuatrociénegas, smithsonite formational temperatures are calculated to have been between 26 to 35 °C. Smithsonite precipitation was favored by near-neutral conditions typical of carbonate terranes, whereas hemimorphite precipitated by reaction with wallrock silica and locally, or episodically, more acidic conditions resulting from sulfide oxidation. Transition to, and stabilization of, the modern desert climate over the past 9000 years from the Late Pleistocene wetter, cooler climate of northern Mexico resulted in episodic drawdown of the water

  7. A regional soil and sediment geochemical study in northern California

    International Nuclear Information System (INIS)

    Goldhaber, Martin B.; Morrison, Jean M.; Holloway, JoAnn M.; Wanty, Richard B.; Helsel, Dennis R.; Smith, David B.

    2009-01-01

    Regional-scale variations in soil geochemistry were investigated in a 20,000-km 2 study area in northern California that includes the western slope of the Sierra Nevada, the southern Sacramento Valley and the northern Coast Ranges. Over 1300 archival soil samples collected from the late 1970s to 1980 in El Dorado, Placer, Sutter, Sacramento, Yolo and Solano counties were analyzed for 42 elements by inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry following a near-total dissolution. These data were supplemented by analysis of more than 500 stream-sediment samples from higher elevations in the Sierra Nevada from the same study site. The relatively high-density data (1 sample per 15 km 2 for much of the study area) allows the delineation of regional geochemical patterns and the identification of processes that produced these patterns. The geochemical results segregate broadly into distinct element groupings whose distribution reflects the interplay of geologic, hydrologic, geomorphic and anthropogenic factors. One such group includes elements associated with mafic and ultramafic rocks including Cr, Ni, V, Co, Cu and Mg. Using Cr as an example, elevated concentrations occur in soils overlying ultramafic rocks in the foothills of the Sierra Nevada (median Cr = 160 mg/kg) as well as in the northern Coast Ranges. Low concentrations of these elements occur in soils located further upslope in the Sierra Nevada overlying Tertiary volcanic, metasedimentary and plutonic rocks (granodiorite and diorite). Eastern Sacramento Valley soil samples, defined as those located east of the Sacramento River, are lower in Cr (median Cr = 84 mg/kg), and are systematically lower in this suite compared to soils from the west side of the Sacramento Valley (median Cr = 130 mg/kg). A second group of elements showing a coherent pattern, including Ca, K, Sr and REE, is derived from relatively silicic rocks types. This group occurs at elevated

  8. A regional soil and sediment geochemical study in northern California

    Science.gov (United States)

    Goldhaber, M.B.; Morrison, J.M.; Holloway, J.M.; Wanty, R.B.; Helsel, D.R.; Smith, D.B.

    2009-01-01

    Regional-scale variations in soil geochemistry were investigated in a 20,000-km2 study area in northern California that includes the western slope of the Sierra Nevada, the southern Sacramento Valley and the northern Coast Ranges. Over 1300 archival soil samples collected from the late 1970s to 1980 in El Dorado, Placer, Sutter, Sacramento, Yolo and Solano counties were analyzed for 42 elements by inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry following a near-total dissolution. These data were supplemented by analysis of more than 500 stream-sediment samples from higher elevations in the Sierra Nevada from the same study site. The relatively high-density data (1 sample per 15 km2 for much of the study area) allows the delineation of regional geochemical patterns and the identification of processes that produced these patterns. The geochemical results segregate broadly into distinct element groupings whose distribution reflects the interplay of geologic, hydrologic, geomorphic and anthropogenic factors. One such group includes elements associated with mafic and ultramafic rocks including Cr, Ni, V, Co, Cu and Mg. Using Cr as an example, elevated concentrations occur in soils overlying ultramafic rocks in the foothills of the Sierra Nevada (median Cr = 160 mg/kg) as well as in the northern Coast Ranges. Low concentrations of these elements occur in soils located further upslope in the Sierra Nevada overlying Tertiary volcanic, metasedimentary and plutonic rocks (granodiorite and diorite). Eastern Sacramento Valley soil samples, defined as those located east of the Sacramento River, are lower in Cr (median Cr = 84 mg/kg), and are systematically lower in this suite compared to soils from the west side of the Sacramento Valley (median Cr = 130 mg/kg). A second group of elements showing a coherent pattern, including Ca, K, Sr and REE, is derived from relatively silicic rocks types. This group occurs at elevated

  9. Regional geochemical maps of the Tonopah 1 degree by 2 degrees Quadrangle, Nevada, based on samples of stream sediment and nonmagnetic heavy-mineral concentrate

    Science.gov (United States)

    Nash, J.T.; Siems, D.F.

    1988-01-01

    This report is part of a series of geologic, geochemical, and geophysical maps of the Tonopah 1° x 2° quadrangle, Nevada, prepared during studies of the area for the Conterminous United States Mineral Assessment Program (CUSMAP). Included here are 21 maps showing the distributions of selected elements or combinations of elements. These regional geochemical maps are based on chemical analyses of the minus-60 mesh (0.25 mm) fraction of stream-sediment samples and the nonmagnetic heavy-mineral concentrate derived from stream sediment. Stream sediments were collected at 1,217 sites. Our geochemical studies of mineralized rock samples provide a framework for evaluating the results from stream sediments.

  10. Sierra Leone Journal of Biomedical Research

    African Journals Online (AJOL)

    MHRL

    Sierra Leone Journal of Biomedical Research. (A publication of the College of Medicine and Allied Health Sciences, University of Sierra Leone). ©Sierra Leone Journal .... was used to. She seemed to have had a change of mind after ingesting.

  11. Sierra Structural Dynamics Theory Manual

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-19

    Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Sierra/SD. For a more detailed description of how to use Sierra/SD , we refer the reader to Sierra/SD, User's Notes . Many of the constructs in Sierra/SD are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Sierra/SD are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature. This page intentionally left blank.

  12. Birds of Sierra de Vallejo, Nayarit, Mexico

    OpenAIRE

    Figueroa-Esquivel, E.M.; Puebla-Olivares, F

    2014-01-01

    Sierra de Vallejo, is considered a priority region for conservation, and is strongly affected by anthropogenic pressures. The inventory of birds are refers to studies in near areas. This study is a concrete contribution of the birds of the mountain chain and north of it. We considered bibliographic records and databases available on the web with records of ocurrence and specimens of scientific collections. Also we perform point counts in different localities inside the...

  13. Distribución geográfica de la avifauna en la Sierra Madre Oriental de San Luis Potosí, México: un análisis regional de su estado de conservación Geographic distribution of birds in the Sierra Madre Oriental of San Luis Potosí, México: a regional analysis of conservation status

    Directory of Open Access Journals (Sweden)

    Francisco Javier Sahagún Sánchez

    2013-06-01

    aves en la región.The Sierra Madre Oriental region in the mexican state of San Luis Potosí is a relevant place for bird conservation at a country level. Therefore the main goal of this study was to analyze the geographic patterns of distribution and the conservation current state of the birds, to support the needs to expand the conservation areas in the future. Data was collected from various databases of zoological museums and collections, and field sampling methods conducted from January 2009 to May 2011. Potential distributions were modeled for 284 species using GARP software and then a map was developed to determine areas with favorable environmental characteristics for the distribution of species richness. Finally, the importance of conservation areas for the potential distribution of birds in the region was evaluated. A total of 359 species were recorded of which 71.4% are permanent residents, 19% are winter migrants and 4% are summer residents. From this total, 41 species were endemic, 47 were species at risk and 149 were neotropical migrants. The largest species richness correspond to oak forests, cloud forests, and tropical moist forests located at altitudes from 100m to 1 500m. Their potential distribution was concentrated towards the center and Southeast of the study area. Only 10% of areas with a high potential conservation was included in areas of priority for bird conservation (AICA and just 3% of all potential areas were under some governmental category of protection. However, no conservation area has a management plan currently applied and monitored. The information generated is important for the development of management proposals for birds conservation in the region.

  14. Climate Resiliency Planning: Making Extreme Event Science Useful for Managers and Planners in Northern Nevada

    Science.gov (United States)

    McCarthy, M.; Kenneston, A.; Wall, T. U.; Brown, T. J.; Redmond, K. T.

    2014-12-01

    Effective climate resiliency planning at the regional level requires extensive interactive dialogue among climate scientists, emergency managers, public health officials, urban planners, social scientists, and policy makers. Engaging federal, tribal, state, local governments and private sector business and infrastructure owners/operators in defining, assessing and characterizing the impacts of extreme events allows communities to understand how different events "break the system" forcing local communities to seek support and resources from state/federal governments and/or the private sector and what actions can be taken proactively to mitigate consequences and accelerate recovery. The Washoe County Regional Resiliency Study was prepared in response to potential climate variability related impacts specific to the Northern Nevada Region. The last several decades have seen dramatic growth in the region, coupled with increased resource demands that have forced local governments to consider how those impacts will affect the region and may, in turn, impact the region's ability to provide essential services. The Western Regional Climate Center of the Desert Research Institute provided a synthesis of climate studies with predictions regarding plausible changes in the local climate of Northern California and Nevada for the next 50 years. In general, these predictions indicate that the region's climate is undergoing a gradual shift, which will primarily affect the frequency, amount, and form of precipitation in the Sierra Nevada and Great Basin. Changes in water availability and other extreme events may have serious and long lasting effects in the Northern Nevada Region, and create a variety of social, environmental and economic concerns. A range of extreme events were considered including Adverse Air Quality, Droughts, Floods, Heat Waves, High Wind, Structure Fires, Wildland Fires, and Major Winter Storms. Due to the complexity of our climate systems, and the difficulty in

  15. African Journals Online: Sierra Leone

    African Journals Online (AJOL)

    Sierra Leone Journal of Biomedical Research. The Sierra Leone Journal of Biomedical Research publishes papers in all fields of Medicine and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular Biology, Pharmaceutical ...

  16. Associations between Mental Health and Ebola-Related Health Behaviors: A Regionally Representative Cross-sectional Survey in Post-conflict Sierra Leone.

    Directory of Open Access Journals (Sweden)

    Theresa S Betancourt

    2016-08-01

    Full Text Available Little attention has been paid to potential relationships between mental health, trauma, and personal exposures to Ebola virus disease (EVD and health behaviors in post-conflict West Africa. We tested a conceptual model linking mental health and trauma to EVD risk behaviors and EVD prevention behaviors.Using survey data from a representative sample in the Western Urban and Western Rural districts of Sierra Leone, this study examines associations between war exposures, post-traumatic stress disorder (PTSD symptoms, depression, anxiety, and personal EVD exposure (e.g., having family members or friends diagnosed with EVD and EVD-related health behaviors among 1,008 adults (98% response rate from 63 census enumeration areas of the Western Rural and Western Urban districts randomly sampled at the height of the EVD epidemic (January-April 2015. Primary outcomes were EVD risk behaviors (14 items, Cronbach's α = 0.84 and EVD prevention behaviors (16 items, Cronbach's α = 0.88. Main predictors comprised war exposures (8 items, Cronbach's α = 0.85, anxiety (10 items, Cronbach's α = 0.93, depression (15 items, Cronbach's α = 0.91, and PTSD symptoms (16 items, Cronbach's α = 0.93. Data were analyzed using two-level, population-weighted hierarchical linear models with 20 multiply imputed datasets. EVD risk behaviors were associated with intensity of depression symptoms (b = 0.05; 95% CI 0.00, 0.10; p = 0.037, PTSD symptoms (b = 0.10; 95% CI 0.03, 0.17; p = 0.008, having a friend diagnosed with EVD (b = -0.04; 95% CI -0.08, -0.00; p = 0.036, and war exposures (b = -0.09; 95% CI -0.17, -0.02; p = 0.013. EVD prevention behaviors were associated with higher anxiety (b = 0.23; 95% CI 0.06, 0.40; p = 0.008, having a friend diagnosed with EVD (b = 0.15; 95% CI 0.04, 0.27; p = 0.011, and higher levels of war exposure (b = 0.45; 95% CI 0.16, 0.74; p = 0.003, independent of mental health. PTSD symptoms were associated with lower levels of EVD prevention behavior

  17. P- and S-body wave tomography of the state of Nevada.

    Energy Technology Data Exchange (ETDEWEB)

    Preston, Leiph

    2010-04-01

    P- and S-body wave travel times collected from stations in and near the state of Nevada were inverted for P-wave velocity and the Vp/Vs ratio. These waves consist of Pn, Pg, Sn and Sg, but only the first arriving P and S waves were used in the inversion. Travel times were picked by University of Nevada Reno colleagues and were culled for inclusion in the tomographic inversion. The resulting tomographic model covers the entire state of Nevada to a depth of {approx}90 km; however, only the upper 40 km indicate relatively good resolution. Several features of interest are imaged including the Sierra Nevada, basin structures, and low velocities at depth below Yucca Mountain. These velocity structure images provide valuable information to aide in the interpretation of geothermal resource areas throughout the state on Nevada.

  18. Ash-flow tuff distribution and fault patterns as indicators of rotation of late-tertiary regional extension, Nevada test site

    International Nuclear Information System (INIS)

    Ander, H.D.

    1983-01-01

    Isopach and structure contour maps generated for Yucca Flat as well as fault pattern analyses of the Nevada Test Site (NTS) can aid in more efficient site selection and site characterization necessary for containment. Furthermore, these geologic studies indicate that most of the alluvial deposition in Yucca Flat was controlled by north-trending faults responding to a regional extension direction oriented approximately 20 0 to 30 0 west of the N50 0 W direction observed today. The Yucca Flat basin-forming Carpetbag and Yucca fault systems seem to be deflected at their southern ends into the northeast-trending Cane Spring and Mine Mountain fault systems. Left-lateral strike-slip displacement of approx. 1.4 km found on these northeasterly faults requires that most of the displacement on the combined fault systems occurred in an extension field oriented approximately N80 0 W. Fault movement in this extensional field postdates the Ammonia Tanks tuff (approx. 11 My) and was strongly active during deposition of some 1100 meters of alluvium in Yucca Flat. Time of rotation of regional extension to the presently active N50 0 W direction is unknown; however, it occurred so recently that it has not greatly modified fault displacement patterns extant at the NTS

  19. An estimated potentiometric surface of the Death Valley region, Nevada and California, developed using geographic information system and automated interpolation techniques

    International Nuclear Information System (INIS)

    D'Agnese, F.A.; Faunt, C.C.; Turner, A.K.

    1998-01-01

    An estimated potentiometric surface was constructed for the Death Valley region, Nevada and California, from numerous, disparate data sets. The potentiometric surface was required for conceptualization of the ground-water flow system and for construction of a numerical model to aid in the regional characterization for the Yucca Mountain repository. Because accurate, manual extrapolation of potentiometric levels over large distances is difficult, a geographic-information-system method was developed to incorporate available data and apply hydrogeologic rules during contour construction. Altitudes of lakes, springs, and wetlands, interpreted as areas where the potentiometric surface intercepts the land surface, were combined with water levels from well data. Because interpreted ground-water recharge and discharge areas commonly coincide with groundwater basin boundaries, these areas also were used to constrain a gridding algorithm and to appropriately place local maxima and minima in the potentiometric-surface map. The resulting initial potentiometric surface was examined to define areas where the algorithm incorrectly extrapolated the potentiometric surface above the land surface. A map of low-permeability rocks overlaid on the potentiometric surface also indicated areas that required editing based on hydrogeologic reasoning. An interactive editor was used to adjust generated contours to better represent the natural water table conditions, such as large hydraulic gradients and troughs, or ''vees''. The resulting estimated potentiometric-surface map agreed well with previously constructed maps. Potentiometric-surface characteristics including potentiometric-surface mounds and depressions, surface troughs, and large hydraulic gradients were described

  20. Fire history of coniferous riparian forests in the Sierra Nevada

    Science.gov (United States)

    K. Van de Water; M. North

    2010-01-01

    Fire is an important ecological process in many western U.S. coniferous forests, yet high fuel loads, rural home construction and other factors have encouraged the suppression of most wildfires. Using mechanical thinning and prescribed burning, land managers often try to reduce fuels in strategic areas with the highest fuel loads. Riparian forests, however, are often...

  1. Charcoal Increases Microbial Activity in Eastern Sierra Nevada Forest Soils

    Directory of Open Access Journals (Sweden)

    Zachary W. Carter

    2018-02-01

    Full Text Available Fire is an important component of forests in the western United States. Not only are forests subjected to wildfires, but fire is also an important management tool to reduce fuels loads. Charcoal, a product of fire, can have major impacts on carbon (C and nitrogen (N cycling in forest soils, but it is unclear how these effects vary by dominant vegetation. In this study, soils collected from Jeffrey pine (JP or lodgepole pine (LP dominated areas and amended with charcoal derived from JP or LP were incubated to assess the importance of charcoal on microbial respiration and potential nitrification. In addition, polyphenol sorption was measured in unamended and charcoal-amended soils. In general, microbial respiration was highest at the 1% and 2.5% charcoal additions, but charcoal amendment had limited effects on potential nitrification rates throughout the incubation. Microbial respiration rates decreased but potential nitrification rates increased over time across most treatments. Increased microbial respiration may have been caused by priming of native organic matter rather than the decomposition of charcoal itself. Charcoal had a larger stimulatory effect on microbial respiration in LP soils than JP soils. Charcoal type had little effect on microbial processes, but polyphenol sorption was higher on LP-derived than JP-derived charcoal at higher amendment levels despite surface area being similar for both charcoal types. The results from our study suggest that the presence of charcoal can increase microbial activity in soils, but the exact mechanisms are still unclear.

  2. Vulnerability of birds to climate change in California's Sierra Nevada

    OpenAIRE

    Rodney B. Siegel; Peter Pyle; James H. Thorne; Andrew J. Holguin; Christine A. Howell; Sarah Stock; Morgan W. Tingley

    2014-01-01

    In a rapidly changing climate, effective bird conservation requires not only reliable information about the current vulnerability of species of conservation concern, but also credible projections of their future vulnerability. Such projections may enable managers to preempt or reduce emerging climate-related threats through appropriate habitat management. We used NatureServe's Climate Change Vulnerability Index (CCVI) to predict vulnerability to climate change of 168 bird species that breed i...

  3. Lower crustal xenoliths, Chinese Peak lava flow, central Sierra Nevada.

    Science.gov (United States)

    Dodge, F.C.W.; Calk, L.C.; Kistler, R.W.

    1986-01-01

    This assemblage of pyroxenite, peridotite and mafic granulite xenoliths in the toe of a 10 m.y. trachybasalt flow remnant overlying late Cretaceous granitic rocks, indicates the presence of a mafic-ultramafic complex beneath this part of central California; orthopyroxenites, websterites and clinopyroxenites are dominant. A few of the xenoliths contain ovoid opaque patches that are apparently pseudomorphs after garnet and have pyralspite garnet compositions; using a garnet-orthopyroxene geobarometer, they indicate a lower crustal depth of approx 40 km. Abundant mafic granulites can be subdivided into those with Al2O3 = or 15% and showing considerable scatter on oxide variation diagrams. The high-alumina granulite xenoliths have relatively low 87Rb/86Sr but high 87Sr/86Sr, whereas the low-alumina and ultramafic xenoliths have a wide range of 87Rb/86Sr, but lower 87Sr/86Sr; the isotopic data indicate roughly the same age as that of overlying granitic plutons (approx 100 m.y.). However, the granitic rocks have initial 87Sr/86Sr ratios intermediate between those of the high-alumina and ultramafic xenoliths, suggesting that they result from the mixing of basaltic magma (represented by the ultramafic rocks) and crustal materials, with subsequent crystal fractionation.-R.A.H.

  4. Characteristics and clinical management of patients admitted to cholera wards in a regional referral hospital during the 2012 epidemic in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Alexander Blacklock

    2015-01-01

    Full Text Available Background and objectives: In 2012, Sierra Leone suffered a nationwide cholera epidemic which affected the capital Freetown and also the provinces. This study aims to describe the characteristics and clinical management of patients admitted to cholera isolation wards of the main referral hospital in the Northern Province and compare management with standard guidelines. Design: All available clinical records of patients from the cholera isolation wards were reviewed retrospectively. There was no active case finding. The following data were collected from the clinical records after patients had left the ward: date of admission, demographics, symptoms, dehydration status, diagnoses, tests and treatments given, length of stay, and outcomes. Results: A total of 798 patients were admitted, of whom 443 (55.5% were female. There were 18 deaths (2.3%. Assessment of dehydration status was recorded in 517 (64.8% of clinical records. An alternative or additional diagnosis was made for 214 patients (26.8%. Intravenous (IV fluids were prescribed to 767 patients (96.1%, including 95% of 141 patients who had documentation of being not severely dehydrated. A history of vomiting was documented in 92.1% of all patients. Oral rehydration solution (ORS was given to 629 (78.8% patients. Doxycycline was given to 380 (47.6% patients, erythromycin to 34 (4.3%, and other antibiotics were used on 247 occasions. Zinc was given to 209 (26.2%. Discussion: This retrospective study highlights the need for efforts to improve the quality of triage, adherence to clinical guidance, and record keeping. Conclusions: Data collection and analysis of clinical practices during an epidemic situation would enable faster identification of those areas requiring intervention and improvement.

  5. Hydrogeologic evaluation and numerical simulation of the Death Valley regional ground-water flow system, Nevada and California

    International Nuclear Information System (INIS)

    D'Agnese, F.A.; Faunt, C.C.; Turner, A.K.; Hill, M.C.

    1997-01-01

    Yucca Mountain is being studied as a potential site for a high-level radioactive waste repository. In cooperation with the U.S. Department of Energy, the U.S. Geological Survey is evaluating the geologic and hydrologic characteristics of the ground-water system. The study area covers approximately 100,000 square kilometers between lat 35 degrees N., long 115 degrees W and lat 38 degrees N., long 118 degrees W and encompasses the Death Valley regional ground-water flow system. Hydrology in the region is a result of both the and climatic conditions and the complex described as dominated by interbasinal flow and may be conceptualized as having two main components: a series of relatively shallow and localized flow paths that are superimposed on deeper regional flow paths. A significant component of the regional ground-water flow is through a thick Paleozoic carbonate rock sequence. Throughout the regional flow system, ground-water flow is probably controlled by extensive and prevalent structural features that result from regional faulting and fracturing. Hydrogeologic investigations over a large and hydrogeologically complex area impose severe demands on data management. This study utilized geographic information systems and geoscientific information systems to develop, store, manipulate, and analyze regional hydrogeologic data sets describing various components of the ground-water flow system

  6. Simulated effects of climate change on the Death Valley regional ground-water flow system, Nevada and California

    International Nuclear Information System (INIS)

    D'Agnese, F.A.; O'Brien, G.M.; Faunt, C.C.; San Juan, C.A.

    1999-01-01

    The US Geological Survey, in cooperation with the US Department of Energy, is evaluating the geologic and hydrologic characteristics of the Death Valley regional flow system as part of the Yucca Mountain Project. As part of the hydrologic investigation, regional, three-dimensional conceptual and numerical ground-water-flow models have been developed to assess the potential effects of past and future climates on the regional flow system. A simulation that is based on climatic conditions 21,000 years ago was evaluated by comparing the simulated results to observation of paleodischarge sites. Following acceptable simulation of a past climate, a possible future ground-water-flow system, with climatic conditions that represent a doubling of atmospheric carbon dioxide, was simulated. The steady-state simulations were based on the present-day, steady-state, regional ground-water-flow model. The finite-difference model consisted of 163 rows, 153 columns, and 3 layers and was simulated using MODFLOWP. Climate changes were implemented in the regional ground-water-flow model by changing the distribution of ground-water recharge. Global-scale, average-annual, simulated precipitation for both past- and future-climate conditions developed elsewhere were resampled to the model-grid resolution. A polynomial function that represents the Maxey-Eakin method for estimating recharge from precipitation was used to develop recharge distributions for simulation

  7. Annotated bibliography for biologic overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada

    International Nuclear Information System (INIS)

    Collins, E.; O'Farrell, T.P.; Rhoads, W.A.

    1981-12-01

    This annotated bibliography was compiled to accompany the Biologic Overview for the Nevada Nuclear Waste Storage Investigations, Nevada Test Site, Nye County, Nevada, EG and G, Santa Barbara Operations Report No. EGG 1183-2443, which documents and synthesizes important biotic information related to Nevada Nuclear Waste Storage Investigations (NNWSI). As such, it is an important part of the NNWSI screening process that was designed to include a systematic, traceable, defensible, and documented basis for a decision to proceed or not with site-specific phases on NTS. Included are all published, and available but unpublished, baseline information on life histories, habitat requirements, distributions, and ecological relationships of the flora and fauna of the region. Special effort was made to include information on endangered, threatened, or sensitive species. 131 references

  8. Studies of geology and hydrology in the Basin and Range province, southwestern United States, for isolation of high-level radioactive waste-characterization of the Death Valley region, Nevada and California

    International Nuclear Information System (INIS)

    Bedinger, M.S.; Sargent, K.A.; Langer, W.H.

    1989-01-01

    The Death Valley region, Nevada and California, in the Basin and Range province, is an area of about 80,200 sq km located in southern Nevada and southeastern California. Precambrian metamorphic and intrusive basement rocks are overlain by a thick section of Paleozoic clastic and evaporitic sedimentary rocks. Mesozoic and Cenozoic rocks include extrusive and intrusive rocks and clastic sedimentary rocks. Structural features within the Death Valley indicate a long and complex tectonic evolution from late Precambrian to the present. Potential repository host media in the region include granite and other coarse-grained plutonic rocks, ashflow tuff, basaltic and andesitic lava flows, and basin fill. The Death Valley region is composed largely of closed topographic basins that are apparently coincident with closed groundwater flow systems. In these systems, recharge occurs sparingly at higher altitudes by infiltration of precipitation or by infiltration of ephemeral runoff. Discharge occurs largely by spring flow and by evaporation and transpiration in the playas. Death Valley proper, for which the region was named, is the ultimate discharge area for a large, complex system of groundwater aquifers that occupy the northeastern part of the region. The deepest part of the system consists of carbonate aquifers that connect closed topographic basins at depth. The discharge from the system occurs in several intermediate areas that are geomorphically, stratigraphically, and structurally controlled. Ultimately, most groundwater flow terminates by discharge to Death Valley; groundwater is discharged to the Colorado River from a small part of the region

  9. Quelques observations sur la dynamique géomorphologique actuelle et passée de deux régions colombiennes: le haut bassin du rio Lebrija et le piemont nord-occidental de la Sierra Nevada de Santa Marta

    Directory of Open Access Journals (Sweden)

    1972-01-01

    áfico, que se hizo venir por fuerza al Perú más de 80,000 chinos. En esa segunda mitad del siglo XIX, el Perú sufría justamente de una escasez muy aguda de mano de obra situación agravada por la liberación de los esclavos negros de una parte y por otra parte a causa de la expansión de las haciendas azucareras, de la construcción de las primeras líneas férreas y de la extracción del guano. Así por ejemplo, introdujeron entre 1860 y 1870 más de 30,000 culies que llegaron sólo al puerto del Callao. En 1876, en Aucallama -provincia de Chancay- trabajaban 1,225 asiáticos o sea más del 66% de la población local. A fines del siglo XIX, muchos habían muerto, algunos lograron volver a China pero otros se habían quedado, instalándose definitivamente en el Perú. A estos últimos se agregó una segunda ola de chinos comerciantes atraídos por el desarrollo del Perú. La mayoría de los chinos se establecieron en la costa donde habían llegado primero, así como en los centros urbanos importantes. Aunque muchos habían trabajado en la sierra en las líneas férreas, pocos de ellos se instalaron en las regiones mineras de altitud. En Acos, pequeña comunidad (de 300 a 400 habitantes del valle de Chancay, implantada en los fundos calientes o 'quebrada de yunga', se encuentra una microcolonia china. ¿Cuáles fueron las circunstancias en que llegaron a ese pueblo de sierra (1,650 m.? ¿Cómo se integraron y cuál fue su papel económico? Este artículo así como el siguiente que tratará específicamente del papel que tuvieron en el desarrollo del pueblo, intentarán contestar a esas preguntas. Para terminar, tenemos que subrayar el hecho de que a la llegada de los chinos, el pueblo de Acos estaba dominado por un conjunto de familias llamadas 'legítimas', cuyo poder se basaba en la propiedad de bienes raíces y la tenencia de la tierra. Contribuyendo a promover la economía de mercado, los chinos se encontraron en conflicto con esas familias de propietarios pero despu

  10. Peruvian Rural School Construction System. SERP 71: Sierra Type.

    Science.gov (United States)

    Cangiano, Miguel

    Based on cooperative action of the government and local communities, the Peruvian Rural School System (SERP 71) evolved from the necessity to reconstruct Peruvian schools of the Sierra region after the earthquake of 1970, and from Peru's new educational reform law (1970) which called for an active-dynamic pupil attitude, continuous updating of…

  11. Geology of Sierra de San Miguel area Rocha department (Uruguay)

    International Nuclear Information System (INIS)

    Muzio, R.; Veroslavsky, G.; Morales, E. . E mail: rossana@fcien.edu.uy

    2004-01-01

    This paper is part of a regional study about Mesozoic magmatism, tectonics and sedimentation in Uruguay. As a result of the geological studies carried out in Sierra de San Miguel area (Rocha department), lithological descriptions, their stratigraphic relationships and their petrographic characterization are presented [es

  12. Ecosystems and diversity of the Sierra Madre Occidental

    Science.gov (United States)

    M. S. Gonzalez-Elizondo; M. Gonzalez-Elizondo; L. Ruacho Gonzalez; I. L. Lopez Enriquez; F. I . Retana Renteria; J. A. Tena Flores

    2013-01-01

    The Sierra Madre Occidental (SMO) is the largest continuous ignimbrite plate on Earth. Despite its high biological and cultural diversity and enormous environmental and economical importance, it is yet not well known. We describe the vegetation and present a preliminary regionalization based on physiographic, climatic, and floristic criteria. A confluence of three main...

  13. Simulation of net infiltration and potential recharge using a distributed-parameter watershed model of the Death Valley region, Nevada and California

    Science.gov (United States)

    Hevesi, Joseph A.; Flint, Alan L.; Flint, Lorraine E.

    2003-01-01

    This report presents the development and application of the distributed-parameter watershed model, INFILv3, for estimating the temporal and spatial distribution of net infiltration and potential recharge in the Death Valley region, Nevada and California. The estimates of net infiltration quantify the downward drainage of water across the lower boundary of the root zone and are used to indicate potential recharge under variable climate conditions and drainage basin characteristics. Spatial variability in recharge in the Death Valley region likely is high owing to large differences in precipitation, potential evapotranspiration, bedrock permeability, soil thickness, vegetation characteristics, and contributions to recharge along active stream channels. The quantity and spatial distribution of recharge representing the effects of variable climatic conditions and drainage basin characteristics on recharge are needed to reduce uncertainty in modeling ground-water flow. The U.S. Geological Survey, in cooperation with the Department of Energy, developed a regional saturated-zone ground-water flow model of the Death Valley regional ground-water flow system to help evaluate the current hydrogeologic system and the potential effects of natural or human-induced changes. Although previous estimates of recharge have been made for most areas of the Death Valley region, including the area defined by the boundary of the Death Valley regional ground-water flow system, the uncertainty of these estimates is high, and the spatial and temporal variability of the recharge in these basins has not been quantified. To estimate the magnitude and distribution of potential recharge in response to variable climate and spatially varying drainage basin characteristics, the INFILv3 model uses a daily water-balance model of the root zone with a primarily deterministic representation of the processes controlling net infiltration and potential recharge. The daily water balance includes precipitation

  14. Selected ground-water data for Yucca Mountain Region, southern Nevada and eastern California, through December 22

    International Nuclear Information System (INIS)

    La Camera, R.J.; Westenburg, C.L.

    1994-01-01

    The U.S. Geological Survey, in support of the U.S. Department of Energy, Yucca Mountain Site-Characterization Project, collects, compiles, and summarizes hydrologic data in the Yucca Mountain region. The data are collected to allow assessments of ground-water resources during studies to determine the potential suitability of Yucca Mountain for storing high-level nuclear waste. Data on ground-water levels at 36 sites, ground-water discharge at 6 sites, ground-water quality at 19 sites, and ground-water withdrawals within Crater Flat, Jackass Flats, Mercury Valley, and the Amargosa Desert are presented. Data on ground-water levels, discharges, and withdrawals collected by other agencies (or as part of other programs) are included to further indicate variations through time at selected monitoring locations. Data are included in this report from 1910 through 1992

  15. Sierra Pacific Power Company Alturas Transmission Line Project, Final Environmental Impact Report/Environmental Impact Statement. Volume 3: Appendices

    International Nuclear Information System (INIS)

    1995-11-01

    Sierra Pacific Power Company has proposed the construction and operation of a 345,000 volt overhead electric power transmission line from Alturas, California to Reno, Nevada. This Environmental Impact Report/Environmental Impact Statement will assess the potential environmental impacts of the proposed project and alternatives. This report contains Appendices A--I which contain the following: glossary/abbreviations; scoping report; structure coordinate summary; air quality; biological resources; geology; noise; visual contrast rating forms; and cultural resources

  16. Mercury Bioaccumulation in Fish in a Region Affected by Historic Gold Morning: The South Yuba River, Deer Creek, and Bear River Watersheds, California, 1999

    National Research Council Canada - National Science Library

    May, Jason T; Hothem, Roger L; Alpers, Charles N; Law, Matthew A

    2000-01-01

    Mercury that was used historically for gold recovery in mining areas of the Sierra Nevada continues to enter local and downstream water bodies, including the Sacramento-San Joaquin Delta and the San...

  17. Southern Nevada ecosystem stressors [Chapter 2

    Science.gov (United States)

    Burton K. Pendleton; Jeanne C. Chambers; Mathew L. Brooks; Steven M. Ostoja

    2013-01-01

    Southern Nevada ecosystems and their associated resources are subject to a number of global and regional/local stressors that are affecting the sustainability of the region. Global stressors include elevated carbon dioxide (CO2) concentrations and associated changes in temperature and precipitation patterns and amounts, solar radiation, and nutrient cycles (Smith and...

  18. One hundred and fifty years of Coulomb stress history along the California-Nevada border, USA

    Science.gov (United States)

    Verdecchia, Alessandro; Carena, Sara

    2015-02-01

    The region north of the Garlock Fault between the Sierra Nevada and Death Valley has experienced at least eight Mw ≥ 6 earthquakes in historical times, beginning with the 1872, Mw 7.5, Owens Valley earthquake. Furthermore, since 1978, the Long Valley Caldera has been undergoing periods of unrest, with earthquake swarms and resurgence. Our goal is to determine whether the 1872 Owens Valley earthquake and the caldera unrest have influenced the evolution of seismicity in the area. We model the evolution of coseismic, postseismic, and interseismic Coulomb stress change (Coulomb failure stress (ΔCFS)) in the region due to both Mw ≥ 6 earthquakes and caldera inflation in the last 150 years. Our results show that the 1872 Owens Valley earthquake has an important influence on subsequent events, strongly encouraging faulting in northern Owens Valley while inhibiting it elsewhere. There is also a correlation between caldera inflation and seismicity in northern Owens Valley, evidenced by the west-to-east migration of earthquakes from the Long Valley Caldera toward the White Mountains immediately following the 1978 caldera inflation event. Finally, we show that a total ΔCFS increase of up to 30 bars in the last 150 years has occurred on part of the White Mountains fault, making it a possible candidate for the next major earthquake in this region.

  19. Modeling interfacial fracture in Sierra.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Arthur A.; Ohashi, Yuki; Lu, Wei-Yang; Nelson, Stacy A. C.; Foulk, James W.,; Reedy, Earl David,; Austin, Kevin N.; Margolis, Stephen B.

    2013-09-01

    This report summarizes computational efforts to model interfacial fracture using cohesive zone models in the SIERRA/SolidMechanics (SIERRA/SM) finite element code. Cohesive surface elements were used to model crack initiation and propagation along predefined paths. Mesh convergence was observed with SIERRA/SM for numerous geometries. As the funding for this project came from the Advanced Simulation and Computing Verification and Validation (ASC V&V) focus area, considerable effort was spent performing verification and validation. Code verification was performed to compare code predictions to analytical solutions for simple three-element simulations as well as a higher-fidelity simulation of a double-cantilever beam. Parameter identification was conducted with Dakota using experimental results on asymmetric double-cantilever beam (ADCB) and end-notched-flexure (ENF) experiments conducted under Campaign-6 funding. Discretization convergence studies were also performed with respect to mesh size and time step and an optimization study was completed for mode II delamination using the ENF geometry. Throughout this verification process, numerous SIERRA/SM bugs were found and reported, all of which have been fixed, leading to over a 10-fold increase in convergence rates. Finally, mixed-mode flexure experiments were performed for validation. One of the unexplained issues encountered was material property variability for ostensibly the same composite material. Since the variability is not fully understood, it is difficult to accurately assess uncertainty when performing predictions.

  20. Birds of Sierra de Vallejo, Nayarit, Mexico

    Directory of Open Access Journals (Sweden)

    Figueroa-Esquivel, E.M.

    2014-01-01

    Full Text Available Sierra de Vallejo, is considered a priority region for conservation, and is strongly affected by anthropogenic pressures. The inventory of birds are refers to studies in near areas. This study is a concrete contribution of the birds of the mountain chain and north of it. We considered bibliographic records and databases available on the web with records of ocurrence and specimens of scientific collections. Also we perform point counts in different localities inside the reserve. We observed a richness of 261 birds species, the family Tyrannidae is the best represented. Of the species recorded, 177 are permanent residents (31 are endemic and 15 are quasi-endemics to Mexico and 73 are migratory; the remaining eleven records have other status. Also 43 species are in endangered categories. We include species that have not been recorded in the lists of the area and records of species expand their ranges at Nayarit. Due to the great diversity of birds observed, it is necesary to continue the research work about habitat use, abundance and monitoring, it will provides the basis for the conservation of birds of Sierra de Vallejo.

  1. Subduction controls on Miocene back-arc lavas from Sierra de Huantraico and La Matancilla, Argentina and new 40Ar/39Ar dating from the Mendoza Region, Argentina

    DEFF Research Database (Denmark)

    Dyhr, Charlotte Thorup; Holm, Paul Martin; Llambias, Eduardo J.

    2013-01-01

    Back-arc volcanism in the western Argentinian provinces of Mendoza and Neuquén has been widespread from the Miocene to historic times. We present a detailed investigation of profiles through two of the major Miocene volcanic areas of the region, the neighboring Huantraico and LaMatancilla plateaus......, including new 40Ar/39Ar age results of major and trace elements as well as Nd, Sr and Pb isotopic data. Four million years of eruptions from 24.4 ± 0.3 Ma (2σ) of alkali olivine basalts with OIB-type incompatible trace element enrichments at La Matancilla (~36.50°S) provide evidence for the presence of back......-arc mantle devoid of subduction-related components. In contrast, the lower Huantraico lavas (~37.30°S) require an atypical back-arc mantle, almost devoid of arc-like components (e.g. low La/Ta = 15–18 and Ba/La = 12–18), but with a more depleted isotopic signature (e.g. 87Sr/86Sr, 0.7033–0.7037) than...

  2. Anfibios y reptiles de la sierra de Cuatro Venados, Oaxaca, México

    OpenAIRE

    Martín-Regalado, N.; Lavariega, M. C.; Gómez-Ugalde, R. M.; Rodríguez-Pérez, C.

    2016-01-01

    Amphibians and reptiles of the Sierra de Cuatro Venados, Oaxaca, Mexico We surveyed amphibian and reptile communities in temperate forest in the Sierra de Cuatro Venados to increase knowledge of the Oaxacan herpetofauna. We obtained 193 visual and 106 voucher records during 38 days of fieldwork. During the study, we recorded 36 of the 40 species predicted to occur in this mountain range: nine amphibians and 27 reptiles, five of which represent new records at the regional scale. Pine-o...

  3. Health complications of female genital mutilation in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Bjälkander O

    2012-07-01

    Full Text Available Owolabi Bjälkander,1 Laurel Bangura,2 Bailah Leigh,3 Vanja Berggren,1 Staffan Bergström,1 Lars Almroth11Division of Global Health, Department of Public Health, Karolinska Institutet, Stockholm, Sweden; 2Inter Africa Committee, Sierra Leone; 3Department of Community Health, College of Medicine and Allied Health Sciences, University of Sierra Leone, Sierra LeoneAbstract: Sierra Leone has one of the highest rates of female genital mutilation (FGM in the world, and yet little is known about the health consequences of the practice.Purpose: To explore whether and what kind of FGM-related health complications girls and women in Sierra Leone experience, and to elucidate their health care-seeking behaviors.Patients and methods: A feasibility study was conducted to test and refine questionnaires and methods used for this study. Thereafter, a cross-section of girls and women (n = 258 attending antenatal care and Well Women Clinics in Bo Town, Bo District, in the southern region and in Makeni Town, Bombali District, in the northern region of Sierra Leone were randomly selected. Participants answered interview-administrated pretested structured questionnaires with open-ended-questions, administrated by trained female personnel.Results: All respondents had undergone FGM, most between 10 and 14 years of age. Complications were reported by 218 respondents (84.5%, the most common ones being excessive bleeding, delay in or incomplete healing, and tenderness. Fever was significantly more often reported by girls who had undergone FGM before 10 years of age compared with those who had undergone the procedure later. Out of those who reported complications, 187 (85.8% sought treatment, with 89 of them visiting a traditional healer, 75 a Sowei (traditional circumciser, and 16 a health professional.Conclusion: The high prevalence rate of FGM and the proportion of medical complications show that FGM is a matter for public health concern in Sierra Leone. Girls who

  4. Mineral potential modelling of gold and silver mineralization in the Nevada Great Basin - a GIS-based analysis using weights of evidence

    Science.gov (United States)

    Mihalasky, Mark J.

    2001-01-01

    segment of the Roberts Mountain thrust front, which bridges the southern ends of the trends. This pattern appears to delineate two well-defined, sub-parallel, northwest?southeast-trending crustal-scale structural zones. These features, here termed the ?Carlin? and ?Cortez? structural zones, are believed to control the regional-scale distribution of the sedimentary rock-hosted occurrences. Mineralizing processes were focused along these structural zones and significant ore deposits exist where they intersect other tectonic zones, favorable host rock-types, and (or) where appropriate physio-chemical conditions were present. The origin and age of the Carlin and Cortez structural zones are not well constrained, however, they are considered to be transcurrent features representing a long-lived, deep-crustal or mantle-rooted zone of weakness. Areas of elevated volcanic rock-hosted mineral potential are principally distributed along two broad and diffuse belts that trend (1) northwest-southeast across southwestern Nevada, parallel to the Sierra Nevada, and (2) northeast-southwest across northern Nevada, extending diagonally from the Sierra Nevada to southern Idaho. The first belt corresponds to the Walker Lane shear zone, a wide region of complex strike-slip faulting. The second, here termed the ?Humboldt shear(?) zone?, may represent a structural zone of transcurrent movement. Together, the Walker Lane and Humboldt shear(?) zones are believed to control the regional-scale distribution of volcanic rock-hosted occurrences. Volcanic rock-hosted mineralization was closely tied to the southward and westward migration of Tertiary magmatism across the region (which may have been mantle plume-driven). Both magmatic and mineralizing processes were localized and concentrated along these structural zones. The Humboldt shear(?) zone may have also affected the distribution of sedimentary rock-hosted mineralization along the Battle Mountain?Eureka (C

  5. Growth of plutons by incremental emplacement of sheets in crystal-rich host: Evidence from Miocene intrusions of the Colorado River region, Nevada, USA

    Science.gov (United States)

    Miller, C.F.; Furbish, D.J.; Walker, B.A.; Claiborne, L.L.; Koteas, G.C.; Bleick, H.A.; Miller, J.S.

    2011-01-01

    Growing evidence supports the notion that plutons are constructed incrementally, commonly over long periods of time, yet field evidence for the multiple injections that seem to be required is commonly sparse or absent. Timescales of up to several million years, among other arguments, indicate that the dominant volume does not remain largely molten, yet if growing plutons are constructed from rapidly solidifying increments it is unlikely that intrusive contacts would escape notice. A model wherein magma increments are emplaced into melt-bearing but crystal-rich host, rather than either solid or crystal-poor material, provides a plausible explanation for this apparent conundrum. A partially solidified intrusion undoubtedly comprises zones with contrasting melt fraction and therefore strength. Depending on whether these zones behave elastically or ductilely in response to dike emplacement, intruding magma may spread to form sheets by either of two mechanisms. If the melt-bearing host is elastic on the relevant timescale, magma spreads rather than continuing to propagate upward, where it encounters a zone of higher rigidity (higher crystal fraction). Similarly, if the dike at first ascends through rigid, melt-poor material and then encounters a zone that is weak enough (poor enough in crystals) to respond ductilely, the ascending material will also spread because the dike tip ceases to propagate as in rigid material. We propose that ascending magma is thus in essence trapped, by either mechanism, within relatively crystal-poor zones. Contacts will commonly be obscure from the start because the contrast between intruding material (crystal-poorer magma) and host (crystal-richer material) is subtle, and they may be obscured even further by subsequent destabilization of the crystal-melt framework. Field evidence and zircon zoning stratigraphy in plutons of the Colorado River region of southern Nevada support the hypothesis that emplacement of magma replenishments into a

  6. Regional potentiometric-surface map of the Great Basin carbonate and alluvial aquifer system in Snake Valley and surrounding areas, Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada

    Science.gov (United States)

    Gardner, Philip M.; Masbruch, Melissa D.; Plume, Russell W.; Buto, Susan G.

    2011-01-01

    Water-level measurements from 190 wells were used to develop a potentiometric-surface map of the east-central portion of the regional Great Basin carbonate and alluvial aquifer system in and around Snake Valley, eastern Nevada and western Utah. The map area covers approximately 9,000 square miles in Juab, Millard, and Beaver Counties, Utah, and White Pine and Lincoln Counties, Nevada. Recent (2007-2010) drilling by the Utah Geological Survey and U.S. Geological Survey has provided new data for areas where water-level measurements were previously unavailable. New water-level data were used to refine mapping of the pathways of intrabasin and interbasin groundwater flow. At 20 of these locations, nested observation wells provide vertical hydraulic gradient data and information related to the degree of connection between basin-fill aquifers and consolidated-rock aquifers. Multiple-year water-level hydrographs are also presented for 32 wells to illustrate the aquifer system's response to interannual climate variations and well withdrawals.

  7. Magmatism, ash-flow tuffs, and calderas of the ignimbrite flareup in the western Nevada volcanic field, Great Basin, USA

    Science.gov (United States)

    Christopher D. Henry,; John, David A.

    2013-01-01

    Sierra Nevada, which was not a barrier to westward flow of ash flows at that time. At least three tuffs flowed eastward across a north-south paleodivide through central Nevada. That tuffs could flow significant distances apparently uphill raises questions about the absolute elevation of the region and the elevation, relief, and location of the paleodivide.Calderas are equant to slightly elongate, at least 12 km in diameter, and as much as 35 km in longest dimension. Exceptional exposure of two caldera complexes that resulted from extensional faulting and tilting show that calderas subsided as much as 5 km as large piston-like blocks; caldera walls were vertical to steeply inward dipping to depths ≥4–5 km, and topographic walls formed by slumping of wall rock into the caldera were only slightly outboard (≤1 km) of structural margins.Most calderas show abundant post-collapse magmatism expressed as resurgent intrusions, ring-fracture intrusions, or intracaldera lavas that are closely related temporally (∼0–0.5 Ma younger) to caldera formation. Granitoid intrusions, which were emplaced at paleodepths ranging from Mountain epithermal gold deposit, few known caldera-related hydrothermal systems are strongly mineralized. Major middle Cenozoic precious and base metal mineral deposits in and along the margins of the western Nevada volcanic field are mostly related to intrusive rocks that preceded caldera-forming eruptions.

  8. Nevada Operations overview

    International Nuclear Information System (INIS)

    Church, B.W.

    1981-01-01

    A brief overview is given of weapon test site decontamination activities carried out by Nevada Operations Office. Tabulated data is given of event name, date, location, year of cleanup, and radioisotopes that were present, activity levels, and cost of cleanup

  9. Special Nevada report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1991-09-23

    This report is submitted to Congress by the Secretary of the Air Force, the Secretary of the Navy, and the Secretary of the Interior pursuant to Section 6 of the Military Lands Withdrawal Act of 1986. It contains an analysis and evaluation of the effects on public health and safety resulting from DOD and Department of Energy (DOE) military and defense-related uses on withdrawn public lands in the State of Nevada and in airspace overlying the State. This report describes the cumulative impacts of those activities on public and private property in Nevada and on plants, fish and wildlife, cultural, historic, scientific, recreational, wilderness and other resources of the public lands of Nevada. An analysis and evaluation of possible measures to mitigate the cumulative effects of the withdrawal of lands and the use of airspace in Nevada for defense-related purposes was conducted, and those considered practical are listed.

  10. Rural migration in southern Nevada

    International Nuclear Information System (INIS)

    Mosser, D.; Soden, D.L.

    1993-01-01

    This study reviews the history of migration in two rural counties in Southern Nevada. It is part of a larger study about the impact of a proposed high-level nuclear waste repository on, in and out-migration patterns in the state. The historical record suggests a boom and bust economic cycle has predominated in the region for the past century creating conditions that should be taken into account, by decision makers, when ascertaining the long-term impacts of the proposed repository

  11. Nevada state revenues analysis

    International Nuclear Information System (INIS)

    1988-06-01

    This report analyzes the major sources of revenue to the Nevada State General Fund for purposes of estimating impacts associated with the siting of a nuclear waste repository at Yucca Mountain in Nye County, Nevada. Each major revenue source is analyzed to identify relationships among the economic or demographic base, the revenue base, and the revenues generated. Trends and changes in the rates and/or base are highlighted. A model is developed for each revenue source to allow impact estimation

  12. Multiple episodes of hydrothermal activity and epithermal mineralization in the southwestern Nevada volcanic field and their relations to magmatic activity, volcanism and regional extension

    International Nuclear Information System (INIS)

    Weiss, S.I.; Noble, D.C.; Jackson, M.C.

    1994-01-01

    Volcanic rocks of middle Miocene age and underlying pre-Mesozoic sedimentary rocks host widely distributed zones of hydrothermal alteration and epithermal precious metal, fluorite and mercury deposits within and peripheral to major volcanic and intrusive centers of the southwestern Nevada volcanic field (SWNVF) in southern Nevada, near the southwestern margin of the Great Basin of the western United States. Radiometric ages indicate that episodes of hydrothermal activity mainly coincided with and closely followed major magmatic pulses during the development of the field and together spanned more than 4.5 m.y. Rocks of the SWNVF consist largely of rhyolitic ash-flow sheets and intercalated silicic lava domes, flows and near-vent pyroclastic deposits erupted between 15.2 and 10 Ma from vent areas in the vicinity of the Timber Mountain calderas, and between about 9.5 and 7 Ma from the outlying Black Mountain and Stonewall Mountain centers. Three magmatic stages can be recognized: the main magmatic stage, Mountain magmatic stage (11.7 to 10.0 Ma), and the late magmatic stage (9.4 to 7.5 Ma)

  13. EMPHASIS(TM)/Nevada Unstructured FEM Implementation Version 2.1.1.

    Energy Technology Data Exchange (ETDEWEB)

    Turner, C. David; Pointon, Timothy D.; Cartwright, Keith

    2014-08-01

    EMPHASIS TM /NEVADA is the SIERRA/NEVADA toolkit implementation of portions of the EMP HASIS TM code suite. The purpose of the toolkit i m- plementation is to facilitate coupling to other physics drivers such as radi a- tion transport as well as to better manage code design, implementation, co m- plexity, and important verification and validation processes. This document describes the theory and implementation of the unstructured finite - element method solver , associated algorithms, and selected verification and valid a- tion . Acknowledgement The author would like to recognize all of the ALEGRA team members for their gracious and willing support through this initial Nevada toolkit - implementation process. Although much of the knowledge needed was gleaned from document a- tion and code context, they were always willing to consult personally on some of the less obvious issues and enhancements necessary.

  14. Reading Comprehension Instruction Practices in Sierra Leone

    NARCIS (Netherlands)

    Hersbach, S.; Denessen, E.J.P.G.; Droop, W.

    2014-01-01

    Aim: In this study an attempt was made to give insight in the way reading comprehension is taught in Sierra Leone. Attention was paid to the didactical strategies and the materials used during reading comprehension instruction. Methodology: Primary school teachers in Sierra Leone (N=43) were

  15. Paleozoic subduction complex and Paleozoic-Mesozoic island-arc volcano-plutonic assemblages in the northern Sierra terrane

    Science.gov (United States)

    Hanson, Richard E.; Girty, Gary H.; Harwood, David S.; Schweickert, Richard A.

    2000-01-01

    This field trip provides an overview of the stratigraphic and structural evolution of the northern Sierra terrane, which forms a significant part of the wall rocks on the western side of the later Mesozoic Sierra Nevada batholith in California. The terrane consists of a pre-Late Devonian subduction complex (Shoo Fly Complex) overlain by submarine arc-related deposits that record the evolution of three separate island-arc systems in the Late Sevonian-Early Mississippian, Permian, and Late Triassic-Jurassic. The two Paleozoic are packages and the underlying Shoo Fly Complex have an important bearing on plate-tectonic processes affecting the convergent margin outboard of the Paleozoic Cordilleran miogeocline, although their original paleogeographic relations to North America are controversial. The third arc package represents an overlap assemblage that ties the terrane to North America by the Late Triassic and helps constrain the nature and timing of Mesozoic orogenesis. Several of the field-trip stops examine the record of pre-Late Devonian subduction contained in the Shoo Fly Complex, as well as the paleovolcanology of the overlying Devonian to Jurassic arc rocks. Excellent glaciated exposures provide the opportunity to study a cross section through a tilted Devonian volcano-plutonic association. Additional stops focus on plutonic rocks emplaced during the Middle Jurassic arc magmatism in the terrane, and during the main pulse of Cretaceous magmatism in the Sierra Nevada batholith to the east.

  16. Sierra Pacific Power Company Alturas Transmission Line Project, Final Environmental Impact Report/Environmental Impact Statement. Volume 2: Comments and responses

    International Nuclear Information System (INIS)

    1995-11-01

    Sierra Pacific Power Company has proposed the construction and operation of a 345,000 volt overhead electric power transmission line from Alturas, California to Reno, Nevada. This Environmental Impact Report/Environmental Impact Statement will assess the potential environmental impacts of the proposed project and alternatives. This report contains public comments which were received on the Draft EIR/S. Significant issues may be identified through public and agency comments

  17. Tritium activities in selected wells on the Nevada Test Site

    International Nuclear Information System (INIS)

    Lyles, B.F.

    1993-05-01

    Literature and data were reviewed related to radionuclides in groundwater on and near the Nevada Test Site. No elevated tritium activities have been reported outside of the major testing regions of the Nevada Test Site. Three wells were identified as having water with above-background (>50 pCi/l) tritium activities: UE-15d Water Well; USGS Water Well A; and USGS Test Well B Ex. Although none of these wells have tritium activities greater than the Nevada State Drinking Water standard (20,000 pCi/l), their time-series tritium trends may be indicative to potential on-site radionuclide migration

  18. Sierra/SM theory manual.

    Energy Technology Data Exchange (ETDEWEB)

    Crane, Nathan Karl

    2013-07-01

    Presented in this document are the theoretical aspects of capabilities contained in the Sierra/SM code. This manuscript serves as an ideal starting point for understanding the theoretical foundations of the code. For a comprehensive study of these capabilities, the reader is encouraged to explore the many references to scientific articles and textbooks contained in this manual. It is important to point out that some capabilities are still in development and may not be presented in this document. Further updates to this manuscript will be made as these capabilites come closer to production level.

  19. 150 Years of Coulomb Stress History Along the California-Nevada Border, USA.

    Science.gov (United States)

    Carena, S.; Verdecchia, A.

    2014-12-01

    The temporal and spatial correlation among earthquakes in diffuse plate boundary zones is not well understood yet. The region north of the Garlock fault between the Sierra Nevada and Death Valley is part of a diffuse plate boundary zone, which absorbs a significant fraction of the plate motion between Pacific and North America. This area has experienced at least eight Mw ≥ 6 earthquakes in historical times, beginning with the 1872 Mw 7.5 Owens Valley earthquake. Furthermore, since 1978 Long Valley caldera has been undergoing periods of unrest, with earthquake swarms and resurgence. Our goal is to determine whether the 1872 Owens Valley earthquake has influenced the seismicity and volcanic activity in the area. We model the evolution of coseismic, interseismic and postseismic Coulomb stress (ΔCFS) in the region due to both earthquakes and caldera activity in the last 150 years. Our results show that the 1872 Owens Valley earthquake strongly encourages faulting in northern Owens Valley. In addition, there is a correlation among smaller events, in the form of a west-to-east migration of earthquakes from Long Valley caldera toward the White Mountains immediately following the 1978 caldera inflation event. The last event in this sequence, the 1986 Mw 6.3 Chalfant Valley earthquake, controls the location of over 80% of its own aftershocks, which occur in areas of positive ΔCFS and reach Mw 5.7. We also calculate the cumulative ΔCFS on several major active faults in the region. Stresses up to 30 bars and 10 bars respectively have accumulated on the White Mountains (Central section) and Deep Springs faults, comparable to the expected stress drop in an average earthquake. Because no surface ruptures more recent than 1.8 ka have been identified on these faults [dePolo, 1989; Lee et al., 2001], we consider them as likely candidates for the next major earthquake in the region.

  20. Nevada Isostatic Gravity Grid

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A 2 kilometer Isostatic anomaly grid for the state of Nevada. Number of columns is 269 and number of rows is 394. The order of the data is from the lower left to the...

  1. Running Parallel Discrete Event Simulators on Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jefferson, D. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-12-03

    In this proposal we consider porting the ROSS/Charm++ simulator and the discrete event models that run under its control so that they run on the Sierra architecture and make efficient use of the Volta GPUs.

  2. Aspen Delineation - Sierra State Parks [ds380

    Data.gov (United States)

    California Natural Resource Agency — The database represents delineations of aspen stands associated with stand assessment data (SIERRA_SP_PTS) collected in aspen stands on lands administered by the...

  3. Three-dimensional hydrogeologic framework model for use with a steady-state numerical ground-water flow model of the Death Valley regional flow system, Nevada and California

    International Nuclear Information System (INIS)

    Belcher, W.R.; Faunt, C.C.; D'Agnese, F.A.

    2002-01-01

    The U.S. Geological Survey, in cooperation with the Department of Energy and other Federal, State, and local agencies, is evaluating the hydrogeologic characteristics of the Death Valley regional ground-water flow system. The ground-water flow system covers and area of about 100,000 square kilometers from latitude 35 degrees to 38 degrees 15 minutes North to longitude 115 degrees to 118 degrees West, with the flow system proper comprising about 45,000 square kilometers. The Death Valley regional ground-water flow system is one of the larger flow systems within the Southwestern United States and includes in its boundaries the Nevada Test Site, Yucca Mountain, and much of Death Valley. Part of this study includes the construction of a three-dimensional hydrogeologic framework model to serve as the foundation for the development of a steady-state regional ground-water flow model. The digital framework model provides a computer-based description of the geometry and composition of the hydro geologic units that control regional flow. The framework model of the region was constructed by merging two previous framework models constructed for the Yucca Mountain Project and the Environmental Restoration Program Underground Test Area studies at the Nevada Test Site. The hydrologic characteristics of the region result from a currently arid climate and complex geology. Interbasinal regional ground-water flow occurs through a thick carbonate-rock sequence of Paleozoic age, a locally thick volcanic-rock sequence of Tertiary age, and basin-fill alluvium of Tertiary and Quaternary age. Throughout the system, deep and shallow ground-water flow may be controlled by extensive and pervasive regional and local faults and fractures. The framework model was constructed using data from several sources to define the geometry of the regional hydrogeologic units. These data sources include (1) a 1:250,000-scale hydrogeologic-map compilation of the region; (2) regional-scale geologic cross

  4. South African Ebola diagnostic response in Sierra Leone: A modular high biosafety field laboratory.

    Directory of Open Access Journals (Sweden)

    Janusz T Paweska

    2017-06-01

    Full Text Available In August 2014, the National Institute for Communicable Diseases (NICD in South Africa established a modular high-biosafety field Ebola diagnostic laboratory (SA FEDL near Freetown, Sierra Leone in response to the rapidly increasing number of Ebola virus disease (EVD cases.The SA FEDL operated in the Western Area of Sierra Leone, which remained a "hotspot" of the EVD epidemic for months. The FEDL was the only diagnostic capacity available to respond to the overwhelming demand for rapid EVD laboratory diagnosis for several weeks in the initial stages of the EVD crisis in the capital of Sierra Leone. Furthermore, the NICD set out to establish local capacity amongst Sierra Leonean nationals in all aspects of the FEDL functions from the outset. This led to the successful hand-over of the FEDL to the Sierra Leone Ministry of Health and Sanitation in March 2015. Between 25 August 2014 and 22 June 2016, the laboratory tested 11,250 specimens mostly from the Western Urban and Western Rural regions of Sierra Leone, of which 2,379 (21.14% tested positive for Ebola virus RNA.The bio-safety standards and the portability of the SA FEDL, offered a cost-effective and practical alternative for the rapid deployment of a field-operated high biocontainment facility. The SA FEDL teams demonstrated that it is highly beneficial to train the national staff in the course of formidable disease outbreak and accomplished their full integration into all operational and diagnostic aspects of the laboratory. This initiative contributed to the international efforts in bringing the EVD outbreak under control in Sierra Leone, as well as capacitating local African scientists and technologists to respond to diagnostic needs that might be required in future outbreaks of highly contagious pathogens.

  5. South African Ebola diagnostic response in Sierra Leone: A modular high biosafety field laboratory.

    Science.gov (United States)

    Paweska, Janusz T; Jansen van Vuren, Petrus; Meier, Gunther H; le Roux, Chantel; Conteh, Ousman S; Kemp, Alan; Fourie, Cardia; Naidoo, Prabha; Naicker, Serisha; Ohaebosim, Phumza; Storm, Nadia; Hellferscee, Orienka; Ming Sun, Lisa K; Mogodi, Busisiwe; Prabdial-Sing, Nishi; du Plessis, Desiree; Greyling, Deidre; Loubser, Shayne; Goosen, Mark; McCulloch, Stewart D; Scott, Terence P; Moerdyk, Alexandra; Dlamini, Wesley; Konneh, Kelfala; Kamara, Idrissa L; Sowa, Dauda; Sorie, Samuel; Kargbo, Brima; Madhi, Shabir A

    2017-06-01

    In August 2014, the National Institute for Communicable Diseases (NICD) in South Africa established a modular high-biosafety field Ebola diagnostic laboratory (SA FEDL) near Freetown, Sierra Leone in response to the rapidly increasing number of Ebola virus disease (EVD) cases. The SA FEDL operated in the Western Area of Sierra Leone, which remained a "hotspot" of the EVD epidemic for months. The FEDL was the only diagnostic capacity available to respond to the overwhelming demand for rapid EVD laboratory diagnosis for several weeks in the initial stages of the EVD crisis in the capital of Sierra Leone. Furthermore, the NICD set out to establish local capacity amongst Sierra Leonean nationals in all aspects of the FEDL functions from the outset. This led to the successful hand-over of the FEDL to the Sierra Leone Ministry of Health and Sanitation in March 2015. Between 25 August 2014 and 22 June 2016, the laboratory tested 11,250 specimens mostly from the Western Urban and Western Rural regions of Sierra Leone, of which 2,379 (21.14%) tested positive for Ebola virus RNA. The bio-safety standards and the portability of the SA FEDL, offered a cost-effective and practical alternative for the rapid deployment of a field-operated high biocontainment facility. The SA FEDL teams demonstrated that it is highly beneficial to train the national staff in the course of formidable disease outbreak and accomplished their full integration into all operational and diagnostic aspects of the laboratory. This initiative contributed to the international efforts in bringing the EVD outbreak under control in Sierra Leone, as well as capacitating local African scientists and technologists to respond to diagnostic needs that might be required in future outbreaks of highly contagious pathogens.

  6. Stratigraphy and Mesozoic–Cenozoic tectonic history of northern Sierra Los Ajos and adjacent areas, Sonora, Mexico

    Science.gov (United States)

    Page, William R.; Gray, Floyd; Iriondo, Alexander; Miggins, Daniel P.; Blodgett, Robert B.; Maldonado, Florian; Miller, Robert J.

    2010-01-01

    Geologic mapping in the northern Sierra Los Ajos reveals new stratigraphic and structural data relevant to deciphering the Mesozoic–Cenozoic tectonic evolution of the range. The northern Sierra Los Ajos is cored by Proterozoic, Cambrian, Devonian, Mississippian, and Pennsylvanian strata, equivalent respectively to the Pinal Schist, Bolsa Quartzite and Abrigo Limestone, Martin Formation, Escabrosa Limestone, and Horquilla Limestone. The Proterozoic–Paleozoic sequence is mantled by Upper Cretaceous rocks partly equivalent to the Fort Crittenden and Salero Formations in Arizona, and the Cabullona Group in Sonora, Mexico.Absence of the Upper Jurassic–Lower Cretaceous Bisbee Group below the Upper Cretaceous rocks and above the Proterozoic–Paleozoic rocks indicates that the Sierra Los Ajos was part of the Cananea high, a topographic highland during the Late Jurassic and Early Cretaceous. Deposition of Upper Cretaceous rocks directly on Paleozoic and Proterozoic rocks indicates that the Sierra Los Ajos area had subsided as part of the Laramide Cabullona basin during Late Cretaceous time. Basal beds of the Upper Cretaceous sequence are clast-supported conglomerate composed locally of basement (Paleozoic) clasts. The conglomerate represents erosion of Paleozoic basement in the Sierra Los Ajos area coincident with development of the Cabullona basin.The present-day Sierra Los Ajos reaches elevations of greater than 2600 m, and was uplifted during Tertiary basin-and-range extension. Upper Cretaceous rocks are exposed at higher elevations in the northern Sierra Los Ajos and represent an uplifted part of the inverted Cabullona basin. Tertiary uplift of the Sierra Los Ajos was largely accommodated by vertical movement along the north-to-northwest-striking Sierra Los Ajos fault zone flanking the west side of the range. This fault zone structurally controls the configuration of the headwaters of the San Pedro River basin, an important bi-national water resource in the US

  7. Implications of seismic reflection and potential field geophysical data on the structural framework of the Yucca Mountain--Crater Flat region, Nevada

    International Nuclear Information System (INIS)

    Brocher, T.M.; Langenheim, V.E.; Hunter, W.C.

    1998-01-01

    Seismic reflection and gravity profiles collected across Yucca Mountain, Nevada, together with geologic data, provide evidence against proposed active detachment faults at shallow depth along the pre-Tertiary-Tertiary contact beneath this potential repository for high-level nuclear waste. The new geophysical data show that the inferred pre-Tertiary-Tertiary contact is offset by moderate-to-high-angle faults beneath Crater Flat and Yucca Mountain, and thus this shallow surface cannot represent an active detachment surface. The reflection lines reveal that the Amargosa Desert rift zone is an asymmetric half-graben having a maximum depth of about 4 km and a width of about 25 km. The east-dipping Bare Mountain fault that bounds this graben to the west can be traced by seismic reflection data to a depth of at least 3.5 km and possibly as deep as 6 km, with a constant dip of 64 degree ± 5 degree. Along the profile the transition from east- to west-dipping faults occurs at or just west of the Solitario Canyon fault, which bounds the western side of Yucca Mountain. The interaction at depth of these east- and west-dipping faults, having up to hundreds of meters offset, is not imaged by the seismic reflection profile. Understanding potential seismic hazards at Yucca Mountain requires knowledge of the subsurface geometry of the faults near Yucca Mountain, since earthquakes generally nucleate and release the greatest amount of their seismic energy at depth. The geophysical data indicate that many fault planes near the potential nuclear waste facility dip toward Yucca Mountain, including the Bare Mountain range-front fault and several west-dipping faults east of Yucca Mountain. Thus, earthquake ruptures along these faults would lie closer to Yucca Mountain than is often estimated from their surface locations and could therefore be more damaging

  8. Paleomagnetism and Anisotropy of Magnetic Susceptibility study of the Miocene Jack Springs Tuff (Nevada, USA)

    Science.gov (United States)

    Shields, S.; Petronis, M. S.; Pluhar, C. J.; Gordon, L.

    2014-12-01

    The mid-Miocene Jack Springs Tuff (JST) outcrops across the western Mina Deflection accommodation zone, west-central Nevada and into eastern California. Previously, the source location for the JST was unknown, yet recent studies northwest of Mono Lake, CA have identified a relatively un-rotated structural block in which to reference the paleomagnetic data. Although new studies have indicated that this block may be rotated up to 13º, we argue that the probable source area is located near the Bodie Hills, CA. At this site, the paleomagnetic reference direction is D = 353°, I = 43°, α95 = 7.7° (Carlson et al, 2013). Based on these data, the JST can be used to measure absolute vertical-axis rotation as well as enable reconstruction of the paleo-topography using the corrected anisotropy of magnetic susceptibility (AMS) data. A total of 19 sites were sampled to constrain Cenozoic to recent vertical axis rotation within the region and AMS experiments were conducted to determine the flow direction of the JST. Curie point estimates indicate that the JST ranges in titanium concentration from 0.042 to 1.10, indicating a low to moderate titanomagnetite phase (Akimoto, 1962). Demagnetization experiments reveal mean destructive fields of the NRM ranging between 15mT and 40mT suggesting that both multi-domain to pseudo-single domain grains are the dominant ferromagnetic phases that carry the remanence and AMS fabric. Preliminary paleomagnetic data yield stable single component demagnetization behavior for most sites that, after structural correction, indicate clockwise vertical axis rotation ranging from +20°± 10° to +60°± 11° between multiple fault blocks. The uncorrected AMS data yield oblate magnetic fabrics that can be used to infer the transport direction, source region, and paleovalley geometry of the JST. These data are tentatively interpreted to indicate west to east transport of the JST across the Mono Basin region into the Mina Deflection that was erupted and

  9. PROBLEMS IN THE ADMISSION TO HIGHER EDUCATION IN THE LOWER SIERRA DE SONORA, CASE: UNIVERSITY OF SIERRA

    Directory of Open Access Journals (Sweden)

    Rubén Ángel Vásquez-Navarro

    2011-05-01

    Full Text Available The aim of this paper is to clarify the issues and find solutions to align somewhat academic models of institutions of higher average level and above found in the central highlands of the state of Sonora, as are the University of Sierra, and the CBTA 53 and confront the culture of the people of the importance of young people studying a degree in that region.The above educational institutions are located in the geographical catchment area and education, in fact, in the same population, in the northeastern state of Sonora. The mountains of Sonora had always intended to have a school of higher education. To justify the town of Montezuma as a geographically strategic point, and thanks to the efforts made by the governor in turn was as the University of Sierra opens its doors to students on the mountain in August 2002.For the analysis of the functioning of an educational institution in the rural sector, should take into account a wide range of factors, however, this work will be key to analyze the dislocation and inconsistency of educational models from an institution of higher average level in relationship to another level, which serve as a unique educational opportunities for the people of Sonora and surrounding Montezuma. In addition, the cultural aspect, which reflects a regional behavior of the inhabitants of the region. La Sierra University is located in the mountainous region of the state of Sonora, in the town of Montezuma, with a catchment area of more than 30 municipalities in this area, which lacked a college until recently time.

  10. Genotypic anomaly in ebola virus strains circulating in magazine wharf Area, Freetown, Sierra Leone, 2015

    NARCIS (Netherlands)

    S.L. Smits (Saskia); S.D. Pas (Suzan); C.B.E.M. Reusken (Chantal); B.L. Haagmans (Bart); P. Pertile; C. Cancedda; K. Dierberg; I. Wurie; A. Kamara; D. Kargbo; S.L. Caddy; A. Arias; L. Thorne; J. Lu; U. Jah; I. Goodfellow; M.P.G. Koopmans D.V.M. (Marion)

    2015-01-01

    textabstractThe Magazine Wharf area, Freetown, Sierra Leone was a focus of ongoing Ebola virus transmission from late June 2015. Viral genomes linked to this area contain a series of 13 T to C substitutions in a 150 base pair intergenic region downstream of viral protein 40 open reading frame,

  11. Evidence and theory for the prediction of tectonic activity in the Basin and Range Province of Nevada and Utah for the next one million years

    International Nuclear Information System (INIS)

    Lovejoy, E.M.P.

    1979-01-01

    Major conclusions of the report are: Important seismic activity in the next one million years will be restricted to the Intermountain Seismic Belt. Minor seismic activity in the same period will be restricted to the Nevada Seismic Belt, Sierra Nevada front, and Reno-Yellowstone lineament. There will be seismic inactivity in the same period in the rest of the Basin and Range Province except locally along high mountain frontal fault zones. In these zones, isostatic unloading will produce slow, secular, mild seismic activity for many millions of years to come

  12. Tectonic Setting of the Gravity Fault and Implications for Ground-Water Resources in the Death Valley Region, Nevada and California

    Science.gov (United States)

    Blakely, R. J.; Sweetkind, D. S.; Faunt, C. C.; Jansen, J. R.; McPhee, D. K.; Morin, R. L.

    2007-12-01

    The Amargosa trough, extending south from Crater Flat basin to the California-Nevada state line, is believed to be a transtensional basin accommodated in part by strike-slip displacement on the northwest-striking State Line fault and normal displacement on the north-striking Gravity fault. The Gravity fault, lying along the eastern margin of the Amargosa trough, was first recognized in the 1970s on the basis of correlations between gravity anomalies and a prominent spring line in Amargosa Valley. The Gravity fault causes an inflection in water-table levels, similar to other (but not all) normal faults in the area. Pools along the spring line, some of which lie within Death Valley National Park and Ash Meadows Wildlife Refuge, include endemic species potentially threatened by increasing agricultural activities in Amargosa Valley immediately to the west, where water tables are declining. Most of the springs and pools lie east of the Gravity fault, however, and it is important to understand the role that the Gravity fault plays in controlling ground-water flow. We have conducted a variety of geophysical investigations at various scales to better understand the tectonic framework of the Amargosa Desert and support new ground-water-flow models. Much of our focus has been on the tectonic interplay of the State Line, Gravity, and other faults in the area using gravity, ground-magnetic, audiomagnetotelluric (AMT), and time-domain electromagnetic (TEM) surveys. With 1250 new gravity measurements from Ash Meadows and Stewart Valley, we have developed a revised three-dimensional crustal model of the Amargosa trough constrained by well information and geologic mapping. The model predicts approximately 2 km of vertical offset on the Gravity fault but also suggests a complex structural framework. The fault is conventionally seen as a simple, down-to-the-west normal fault juxtaposing permeable pre-Tertiary carbonate rocks to the east against less permeable Tertiary sediments to

  13. Sierra/SolidMechanics 4.46 Example Problems Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Plews, Julia A.; Crane, Nathan K; de Frias, Gabriel Jose; Le, San; Littlewood, David John; Merewether, Mark Thomas; Mosby, Matthew David; Pierson, Kendall H.; Porter, Vicki L.; Shelton, Timothy; Thomas, Jesse David; Tupek, Michael R.; Veilleux, Michael

    2018-03-01

    Presented in this document are tests that exist in the Sierra/SolidMechanics example problem suite, which is a subset of the Sierra/SM regression and performance test suite. These examples showcase common and advanced code capabilities. A wide variety of other regression and verification tests exist in the Sierra/SM test suite that are not included in this manual.

  14. The Sierra de Cabral range: a restraining bend related to the Sierra Ballena shear zone in Dom Feliciano belt

    International Nuclear Information System (INIS)

    Masquelin, H.

    2010-01-01

    Restraining and releasing bends occurring in all crustal environments are common but enigmatic features of strike-slip fault systems. They can be reported in all scales of observation. Regional-scale restraining bends are sites of mountain building, transpressional deformation and basement exhumation. Releasing bends are sites of subsidence, transtensional deformation and pull-apart basins. The Dom Feliciano Belt of Southern Uruguay has two main structures observed from the outer space: (i) the Sierra Ballena Shear Zone and (ii) the Sierra de Cabral flexure located to the SW of the former. Although a transpressional regime is commonly accepted for the Dom Feliciano Belt, the available tectonic models do not provide satisfactory explanations for its building mechanism. A restraining bend is proposed at the SW termination of Sierra Ballena strike-slip ductile shear zone. In a key-area (Alvariza Range) the relationship between the Zanja del Tigre volcanic-detritic and the calcareous succession shows three en-échelon upright bends of the same quartzite hanging-wall between two sub-vertical strike-slip faults, suggesting the existence of a shortened strike-slip duplex operating in viscous-elastic rheology. The deformation partitioning includes strike-slip and dip-slip simple-shear components as well as one contractional pure-shear component. Because restraining bends were scarcely described in Neoproterozoic low-grade regional exhumation conditions, this structural framework would be a natural laboratory to study fault kinematics, fault dynamics, their associated deformation and the tectonic and erosion constraints related to the exhumation of many crystalline terrains

  15. The metamorphic basement of the southern Sierra de Aconquija, Eastern Sierras Pampeanas: Provenance and tectonic setting of a Neoproterozoic back-arc basin

    Science.gov (United States)

    Cisterna, Clara Eugenia; Altenberger, Uwe; Mon, Ricardo; Günter, Christina; Gutiérrez, Antonio

    2018-03-01

    (wackes, shales, Fe-shales and minor litharenites) are characteristic for turbidity currents deposits along tectonically active region. They are also commonly associated with calcareous clays (marbles), commonly observed in the evolution of basins with slope and shelf derived carbonate turbidites. The amphibolites members are probably derived from lava-flows synchronous with the sedimentation during the basin evolution. The basin was controlled by a continental island arc possible evolving to a back-arc setting, as indicated for the mixed nature of the inferred source. The metasedimentary sequence from the Cuesta de La Chilca have petrographic, structural and strong chemical similarities, building a north-south striking belt from the north of the Sierra de Aconquija and to the south along the Sierra de Ancasti (La Majada area). The observed similarities allow to present this portion of the Eastern Sierras Pampeanas as a crustal block that records the sedimentary sequences developed along the geodynamic context of the southwestern margin of Gondwana during the Neoproterozoic and Early Palaeozoic.

  16. Estudio de la biodegradación de bolsas oxo - biodegradables en agua dulce y salada, simulando condiciones ambientales de Costa, Sierra y Oriente Ecuatoriano.

    OpenAIRE

    Escobar Silva, Nelly Jacqueline

    2014-01-01

    This work allowed the study of biodegradation of four types of oxo-biodegradable bags by environmental conditions simulated in fresh and salt water of the Costa, Sierra and Oriente regions. El presente trabajo permitió el estudio de la biodegradación de cuatro tipos de bolsas oxo-biodegradables mediante condiciones ambientales simuladas en el agua dulce y salada de las regiones Costa, Sierra y Oriente ecuatoriano.

  17. Sierra toolkit computational mesh conceptual model

    International Nuclear Information System (INIS)

    Baur, David G.; Edwards, Harold Carter; Cochran, William K.; Williams, Alan B.; Sjaardema, Gregory D.

    2010-01-01

    The Sierra Toolkit computational mesh is a software library intended to support massively parallel multi-physics computations on dynamically changing unstructured meshes. This domain of intended use is inherently complex due to distributed memory parallelism, parallel scalability, heterogeneity of physics, heterogeneous discretization of an unstructured mesh, and runtime adaptation of the mesh. Management of this inherent complexity begins with a conceptual analysis and modeling of this domain of intended use; i.e., development of a domain model. The Sierra Toolkit computational mesh software library is designed and implemented based upon this domain model. Software developers using, maintaining, or extending the Sierra Toolkit computational mesh library must be familiar with the concepts/domain model presented in this report.

  18. Landsat-Derived Estimates of Mangrove Extents in the Sierra Leone Coastal Landscape Complex during 1990-2016.

    Science.gov (United States)

    Mondal, Pinki; Trzaska, Sylwia; de Sherbinin, Alex

    2017-12-21

    This study provides the first assessment of decadal changes in mangrove extents in Sierra Leone. While significant advances have been made in mangrove mapping using remote sensing, no study has documented long-term changes in mangrove extents in Sierra Leone-one of the most vulnerable countries in West Africa. Such understanding is critical for devising regional management strategies that can support local livelihoods. We utilize multi-date Landsat data and cloud computational techniques to quantify spatiotemporal changes in land cover, with focus on mangrove ecosystems, for 1990-2016 along the coast of Sierra Leone. We specifically focus on four estuaries-Scarcies, Sierra Leone, Yawri Bay, and Sherbro. We relied on the k-means approach for an unsupervised classification, and validated the classified map from 2016 using ground truth data collected from Sentinel-2 and high-resolution images and during field research (accuracy: 95%). Our findings indicate that the Scarcies river estuary witnessed the greatest mangrove loss since 1990 (45%), while the Sierra Leone river estuary experienced mangrove gain over the last 26 years (22%). Overall, the Sierra Leone coast lost 25% of its mangroves between 1990 and 2016, with the lowest coverage in 2000, during the period of civil war (1991-2002). However, natural mangrove dynamics, as supported by field observations, indicate the potential for regeneration and sustainability under carefully constructed management strategies.

  19. The Special Court for Sierra Leone

    DEFF Research Database (Denmark)

    Damgaard, Ciara Therése

    2004-01-01

    The focus of this article is the Special Court for Sierra Leone and the extent to which it can be said that the Special Court has already challenged, or will, in the future, challenge the tradition of impunity for gender-based crimes. In this regard, an analysis is undertaken of the Special Court......'s Statute, Rules of Procedure and Evidence and practice to date, in order to determine its treatment of gender-based crimes and whether it can be said that the Special Court for Sierra Leone challenges the tradition of impunity for gender-based crimes. Udgivelsesdato: december 2004...

  20. Geologic map of the Bodie Hills, California and Nevada

    Science.gov (United States)

    John, David A.; du Bray, Edward A.; Box, Stephen E.; Vikre, Peter G.; Rytuba, James J.; Fleck, Robert J.; Moring, Barry C.

    2015-01-01

    The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late Pleistocene Aurora volcanic field (John and others, 2012). Upper Miocene to Pliocene sedimentary deposits, mostly basin-filling sediments, gravel deposits, and fanglomerates, lap onto the west, north, and east sides of the Bodie Hills, where they cover older Miocene volcanic rocks. Quaternary surficial deposits, including extensive colluvial, fluvial, glacial, and lacustrine deposits, locally cover all older rocks. Miocene and younger rocks are tilted ≤30° in variable directions. These rocks are cut by several sets of high-angle faults that exhibit a temporal change from conjugate northeast-striking left-lateral and north-striking right-lateral oblique-slip faults in rocks older than about 9 Ma to north- and northwest-striking dip-slip faults in late Miocene rocks. The youngest faults are north-striking normal and northeast-striking left-lateral oblique-slip faults that cut Pliocene-Pleistocene rocks. Numerous hydrothermal systems were active during Miocene magmatism and formed extensive zones of hydrothermally altered rocks and several large mineral deposits, including gold- and silver-rich veins in the Bodie and Aurora mining districts (Vikre and others, in press).

  1. Late cenozoic evolution of Fortymile Wash: Major change in drainage pattern in the Yucca Mountain, Nevada region during late miocene volcanism

    International Nuclear Information System (INIS)

    Lundstrom, S.C.; Warren, R.G.

    1994-01-01

    The site characterization of Yucca Mountain, NV as a potential high level nuclear waste repository includes study of the surficial deposits as a record of the paleoenvironmental history of the Yucca Mountain region. An important aspect of this history is an understanding of the evolution of paleogeography leading to establishment of the present drainage pattern. Establishment of drainage basin evolution is needed before geomorphic response to paleoclimate and tectonics can be assessed, because a major change in drainage basin geometry can predominantly affect the sedimentary record. Because alluvial aquifers are significant to regional hydrology, a major change in surface drainage resulting in buried alluvium could have hydrogeologic significance. In this paper, we report on geologic evidence for a major modification in surface drainage pattern in the Yucca Mountain region, resulting in the probable establishment of the Fortymile Wash drainage basin by latest Miocene time

  2. Facies Analysis of Tertiary Basin-Filling Rocks of the Death Valley Regional Ground-Water System and Surrounding Areas, Nevada and California; TOPICAL

    International Nuclear Information System (INIS)

    Sweetkind, D.S.; Fridrich, C.J.; Taylor, Emily

    2002-01-01

    Existing hydrologic models of the Death Valley region typically have defined the Cenozoic basins as those areas that are covered by recent surficial deposits, and have treated the basin-fill deposits that are concealed under alluvium as a single unit with uniform hydrologic properties throughout the region, and with depth. Although this latter generalization was known to be flawed, it evidently was made because available geologic syntheses did not provide the basis for a more detailed characterization. As an initial attempt to address this problem, this report presents a compilation and synthesis of existing and new surface and subsurface data on the lithologic variations between and within the Cenozoic basin fills of this region. The most permeable lithologies in the Cenozoic basin fills are freshwater limestones, unaltered densely welded tuffs, and little-consolidated coarse alluvium. The least permeable lithologies are playa claystones, altered nonwelded tuffs, and tuffaceous and cl ay-matrix sediments of several types. In all but the youngest of the basin fills, permeability probably decreases strongly with depth owing to a typically increasing abundance of volcanic ash or clay in the matrices of the clastic sediments with increasing age (and therefore with increasing depth in general), and to increasing consolidation and alteration (both hydrothermal and diagenetic) with increasing depth and age. This report concludes with a categorization of the Cenozoic basins of the Death Valley region according to the predominant lithologies in the different basin fills and presents qualitative constraints on the hydrologic properties of these major lithologic categories

  3. Nevada Test Site Wetlands Assessment

    Energy Technology Data Exchange (ETDEWEB)

    D. J. Hansen

    1997-05-01

    This report identifies 16 Nevada Test Site (NTS) natural water sources that may be classified by the U.S. Army Corps of Engineers (USACE) as jurisdictional wetlands and identifies eight water sources that may be classified as waters of the United States. These water sources are rare, localized habitats on the NTS that are important to regional wildlife and to isolated populations of water tolerant plants and aquatic organisms. No field investigations on the NTS have been conducted in the past to identify those natural water sources which would be protected as rare habitats and which may fall under regulatory authority of the Clean Water Act (CWA) of 1997. This report identifies and summarizes previous studies of NTS natural water sources, and identifies the current DOE management practices related to the protection of NTS wetlands. This report also presents management goals specific for NTS wetlands that incorporate the intent of existing wetlands legislation, the principles of ecosystem management, and the interests of regional land managers and other stakeholders.

  4. Geology of the Yucca Mountain Region, Chapter in Stuckless, J.S., ED., Yucca Mountain, Nevada - A Proposed Geologic Repository for High-Level Radioactive Waste

    Energy Technology Data Exchange (ETDEWEB)

    J.S. Stuckless; D. O' Leary

    2006-09-25

    Yucca Mountain has been proposed as the site for the Nation's first geologic repository for high-level radioactive waste. This chapter provides the geologic framework for the Yucca Mountain region. The regional geologic units range in age from late Precambrian through Holocene, and these are described briefly. Yucca Mountain is composed dominantly of pyroclastic units that range in age from 11.4 to 15.2 Ma. The proposed repository would be constructed within the Topopah Spring Tuff, which is the lower of two major zoned and welded ash-flow tuffs within the Paintbrush Group. The two welded tuffs are separated by the partly to nonwelded Pah Canyon Tuff and Yucca Mountain Tuff, which together figure prominently in the hydrology of the unsaturated zone. The Quaternary deposits are primarily alluvial sediments with minor basaltic cinder cones and flows. Both have been studied extensively because of their importance in predicting the long-term performance of the proposed repository. Basaltic volcanism began about 10 Ma and continued as recently as about 80 ka with the eruption of cones and flows at Lathrop Wells, approximately 10 km south-southwest of Yucca Mountain. Geologic structure in the Yucca Mountain region is complex. During the latest Paleozoic and Mesozoic, strong compressional forces caused tight folding and thrust faulting. The present regional setting is one of extension, and normal faulting has been active from the Miocene through to the present. There are three major local tectonic domains: (1) Basin and Range, (2) Walker Lane, and (3) Inyo-Mono. Each domain has an effect on the stability of Yucca Mountain.

  5. Geology of the Yucca Mountain Region, Chapter in Stuckless, J.S., ED., Yucca Mountain, Nevada - A Proposed Geologic Repository for High-Level Radioactive Waste

    International Nuclear Information System (INIS)

    J.S. Stuckless; D. O'Leary

    2006-01-01

    Yucca Mountain has been proposed as the site for the Nation's first geologic repository for high-level radioactive waste. This chapter provides the geologic framework for the Yucca Mountain region. The regional geologic units range in age from late Precambrian through Holocene, and these are described briefly. Yucca Mountain is composed dominantly of pyroclastic units that range in age from 11.4 to 15.2 Ma. The proposed repository would be constructed within the Topopah Spring Tuff, which is the lower of two major zoned and welded ash-flow tuffs within the Paintbrush Group. The two welded tuffs are separated by the partly to nonwelded Pah Canyon Tuff and Yucca Mountain Tuff, which together figure prominently in the hydrology of the unsaturated zone. The Quaternary deposits are primarily alluvial sediments with minor basaltic cinder cones and flows. Both have been studied extensively because of their importance in predicting the long-term performance of the proposed repository. Basaltic volcanism began about 10 Ma and continued as recently as about 80 ka with the eruption of cones and flows at Lathrop Wells, approximately 10 km south-southwest of Yucca Mountain. Geologic structure in the Yucca Mountain region is complex. During the latest Paleozoic and Mesozoic, strong compressional forces caused tight folding and thrust faulting. The present regional setting is one of extension, and normal faulting has been active from the Miocene through to the present. There are three major local tectonic domains: (1) Basin and Range, (2) Walker Lane, and (3) Inyo-Mono. Each domain has an effect on the stability of Yucca Mountain

  6. Summary Report of Depleted Uranium (DU) Survey Actions at Nevada Test and Training Range (NTTR), Airspace Region 63B, Active Target Complex 10 (63-10)

    Science.gov (United States)

    2016-09-15

    Sep 2016. a. In October 1992, the former Armstrong Laboratory Health Physics Function, now USAFSAM/OEC, took air and radiation samples during...in primary drainage areas, evidenced by the lack of DU activity above background in soil samples . However, survey measurements revealed elevated DU...and soil sampling in the primary drainage regions south of the active targets. It was also recommended that access to another area (NTTR 63-08

  7. Explaining Violence in Sierra Leone's Civil War

    African Journals Online (AJOL)

    Explaining the violence of civil war is never a simple task for the scholar. In the case of the Sierra Leone, paradoxically, the task has in some ways been rendered more difficult by the sheer variety of compelling scholarship on the question. This paper seeks to identify the most useful of the explanations offered thus far, and ...

  8. Rebellion and Agrarian Tensions in Sierra Leone

    NARCIS (Netherlands)

    Peters, K.; Richards, P.

    2011-01-01

    This paper assesses the extent to which customary governance in Sierra Leone can be held responsible for an increasingly unstable two-class agrarian society. A case is made for regarding the civil war (1991–2002) as being an eruption of long-term, entrenched agrarian tensions exacerbated by chiefly

  9. Sierra Leone Journal of Biomedical Research: Submissions

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... Sierra Leone Journal of Biomedical Research (SLJBR) publishes papers in all ... An original article should give sufficient detail of experimental procedures for .... For references cited in a paper which has been accepted for publication but not ...

  10. Rice genetic resources in postwar Sierra Leone

    NARCIS (Netherlands)

    Chakanda, R.T.M.

    2009-01-01

    This research presents the effect of the 10-year long civil war in Sierra Leone on rice genetic resources, using farmers and their seed systems in three selected districts as reference points. The war disrupted all forms of production and development in the country and like other sectors of the

  11. Sierra Leone Journal of Biomedical Research

    African Journals Online (AJOL)

    The Sierra Leone Journal of Biomedical Research publishes papers in all fields of Medicine and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular Biology, Pharmaceutical Sciences, Biotechnology in relation to Medicine, ...

  12. Nevada Transportation Options Study

    International Nuclear Information System (INIS)

    P. GEHNER; E.M. WEAVER; L. FOSSUM

    2006-01-01

    This study performs a cost and schedule analysis of three Nevada Transportation options that support waste receipt at the repository. Based on the U.S. Department of Energy preference for rail transportation in Nevada (given in the Final Environmental Impact Statement), it has been assumed that a branch rail line would be constructed to support waste receipt at the repository. However, due to potential funding constraints, it is uncertain when rail will be available. The three Nevada Transportation options have been developed to meet a varying degree of requirements for transportation and to provide cost variations used in meeting the funding constraints given in the Technical Direction Letter guidelines for this study. The options include combinations of legal-weight truck, heavy-haul truck, and rail. Option 1 uses a branch rail line that would support initial waste receipt at the repository in 2010. Rail transportation would be the primary mode, supplemented by legal weight trucks. This option provides the highest level of confidence in cost and schedule, lowest public visibility, greatest public acceptability, lowest public dose, and is the recommended option for support of waste receipt. The completion of rail by 2010 will require spending approximately $800 million prior to 2010. Option 2 uses a phased rail approach to address a constrained funding scenario. To meet funding constraints, Option 2 uses a phased approach to delay high cost activities (final design and construction) until after initial waste receipt in 2010. By doing this, approximately 95 percent of the cost associated with completion of a branch rail line is deferred until after 2010. To support waste receipt until a branch rail line is constructed in Nevada, additional legal-weight truck shipments and heavy-haul truck shipments (on a limited basis for naval spent nuclear fuel) would be used to meet the same initial waste receipt rates as in Option 1. Use of heavy-haul shipments in the absence

  13. Distribución geográfica de la avifauna en la Sierra Madre Oriental de San Luis Potosí, México: un análisis regional de su estado de conservación

    Directory of Open Access Journals (Sweden)

    Francisco Javier Sahagún Sánchez

    2013-06-01

    Full Text Available La región de la Sierra Madre Oriental (SMO en el estado de San Luis Potosí en México es considerada un sitio de relevancia para la conservación de la avifauna a nivel nacional. Por lo anterior, el objetivo de este estudio fue analizar la distribución geográfica de las aves en la zona para identificar las áreas con mayor concentración de la riqueza y evaluar su estado actual de conservación para fundamentar la necesidad de incrementar la superficie dedicada a las áreas naturales protegidas en el futuro. Se recolectó información proveniente de diversas bases de datos de colecciones y museos, además de realizar trabajo de campo en el periodo de enero 2009 a Mayo 2011. Se modelaron las distribuciones potenciales para 284 especies con el programa GARP y se elaboró un mapa de consenso para determinar la ubicación espacial de las áreas con condiciones ambientales para soportar el mayor número de especies. Finalmente, se evaluó la representatividad de las zonas dedicadas a la conservación para las aves. Se registraron 357 especies, de las cuales el 71.4% son residentes permanentes, 19% son migratorias de invierno y 3.9% residentes de verano. Del total, 41 especies son endémicas y 48 se encuentran en alguna categoría de riesgo; la mayor concentración de especies se presentó en las coberturas de bosques de encino, bosques mesófilos y selvas medianas y bajas caducifolias, en un intervalo altitudinal entre 100-1 500m con una más alta cantidad de nichos en la parte centro y hacia el sur y este de la región. Sólo el 10% de las zonas con alto potencial de número de especies está incluido como área de importancia para la conservación de las aves y el 3% del total de áreas potenciales está bajo alguna categoría estatal de protección; sin embargo, ninguna de las áreas tiene un plan de manejo que esté siendo aplicado y monitoreado. La información generada es importante para el desarrollo de propuestas de conservación para las

  14. Nevada Test Site, Nye County, Nevada. Final environmental impact statement

    International Nuclear Information System (INIS)

    1977-09-01

    This environmental statement for the Nevada Test Site (NTS) considers underground nuclear detonations with yields of one megaton or less, along with the preparations necessary for such detonations. The testing activities considered also include other continuing and intermittent activities, both nuclear and nonnuclear, which can best be conducted in the remote and controlled area of the Nevada Test Site. These activities are listed, with emphasis on weapons testing programs which do not remain static

  15. Nevada Test Site, Nye County, Nevada. Final environmental impact statement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1977-09-01

    This environmental statement for the Nevada Test Site (NTS) considers underground nuclear detonations with yields of one megaton or less, along with the preparations necessary for such detonations. The testing activities considered also include other continuing and intermittent activities, both nuclear and nonnuclear, which can best be conducted in the remote and controlled area of the Nevada Test Site. These activities are listed, with emphasis on weapons testing programs which do not remain static.

  16. Nevada`s role in the hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Vaeth, T. [Dept. of Energy, Las Vegas, NV (United States)

    1997-12-31

    The paper discusses the promise of hydrogen and its possible applications, barriers to its development, the role that the Nevada Test Site could play if it were made more available to public and private institutions for research, and the ``clean city`` concept being developed jointly with California, Utah, and Nevada. This concept would create a ``clean corridor`` along the route from Salt Lake City through Reno to Sacramento, Los Angeles, Las Vegas, and back to Salt Lake City.

  17. Preliminary evaluation of the importance of existing hydraulic-head observation locations to advective-transport predictions, Death Valley regional flow system, California and Nevada

    International Nuclear Information System (INIS)

    Hill, M.C.; Ely, D.M.; Tiedeman, C.R.; O'Brien, G.M.; D'Agnese, F.A.; Faunt, C.C.

    2001-01-01

    When a model is calibrated by nonlinear regression, calculated diagnostic statistics and measures of uncertainty provide a wealth of information about many aspects of the system. This report presents a method of ranking the likely importance of existing observation locations using measures of prediction uncertainty. It is suggested that continued monitoring is warranted at more important locations, and unwarranted or less warranted at less important locations. The report develops the methodology and then demonstrates it using the hydraulic-head observation locations of a three-layer model of the Death Valley regional flow system (DVRFS). The predictions of interest are subsurface transport from beneath Yucca Mountain and 14 underground Test Area (UGTA) sites. The advective component of transport is considered because it is the component most affected by the system dynamics represented by the regional-scale model being used. The problem is addressed using the capabilities of the U.S. Geological Survey computer program MODFLOW-2000, with its ADVective-Travel Observation (ADV) Package, and an additional computer program developed for this work

  18. Reestablishment of the Ancestral Cascades Arc in Western Nevada and Eastern California by Rollback of the Shallow Farallon Slab

    Science.gov (United States)

    Henry, C. D.; Cousens, B.; John, D. A.; Colgan, J. P.

    2009-12-01

    The character and even existence of an ancestral Tertiary Cascades arc in western Nevada and eastern California south of the modern arc are controversial. Based on extensive published and new data on the regional distribution, timing, style, and composition of magmatism, we conclude that an ancestral arc was established by WSW migration of magmatism into western NV and the northeastern Sierra Nevada in the Oligocene and Miocene as a result of progressive rollback of the shallow subducted slab. Magma migration started with the well-known southward sweep through NE NV and NW UT between ~46 and 36 Ma. By ~30 Ma, migration of the leading edge and central belt of activity was much more WSW, especially after removing younger ~E-W extension. Locally sourced, initially dispersed and small volume, intermediate to mafic lavas erupted in western NV and northeastern CA by ~30 Ma and the eastern Sierra Nevada by ~28 Ma, contemporaneous with the much more voluminous ignimbrite flare-up in central NV. As migration continued, the ignimbrite flare-up tapered off. A voluminous, NNW-trending, dominantly effusive volcanic belt developed by ~22-18 Ma in western NV and was continuous from the Bodie Hills (CA/NV) to the Warner Range (northeast CA) by ~16-15 Ma. The volcanic belt was dominated by intermediate to mafic magmas compositionally similar to those of the modern south Cascades arc but reflecting melting of an old, subduction-modified lithosphere (Cousens et al. 2008; Geosphere). Extensive middle Miocene bimodal rocks related to the Yellowstone hotspot cover these rocks in NW NV, NE CA, and SE OR, but 30-23 Ma, intermediate to mafic and lesser silicic rocks are voluminous wherever older rocks are exposed below the middle Miocene rocks. Between ~25 Ma and the present, magmatism migrated WSW at an average rate of ~8 km/Ma but was at least partly stepwise, as exemplified by an ~50 km westward step at 2 Ma in the Lassen area (Guffanti et al. 1990, JGR). The magmatic belt was as much

  19. Ground-water data for the Nevada Test Site and selected other areas in South-Central Nevada, 1992--1993

    International Nuclear Information System (INIS)

    1995-01-01

    The US Geological Survey, in support of the US Department of Energy Environmental Restoration and Hydrologic Resources Management Programs, collects and compiles hydrogeologic data to aid in characterizing the regional and local ground-water flow systems underlying the Nevada Test Site and vicinity. This report presents selected ground-water data collected from wells and test holes at and in the vicinity of the Nevada Test Site. Depth-to-water measurements were made during water year 1993 at 55 sites at the Nevada Test Site and 43 regional sites in the vicinity of the Nevada Test Site. Depth to water ranged from 87.7 to 674.6 meters below land surface at the Nevada Test Site and from 6.0 to 444.7 meters below land surface at sites in the vicinity of the Nevada Test Site. Depth-to-water measurements were obtained using the wire-line, electric-tape, air-line, and steel-tape devices. Total measured ground-water withdrawal from the Nevada Test Site during the 1993 calendar year was 1,888.04 million liters. Annual ground-water withdrawals from 14 wells ranged from 0.80 million to 417.20 million liters. Tritium concentrations from four samples at the Nevada Test Site and from three samples in the vicinity of the Nevada Test Site collected during water year 1993 ranged from near 0 to 27,676.0 becquerels per liter and from near 0 to 3.9 becquerels per liter, respectively

  20. Temporal constraints on the tectonic evolution of Sierra De Famatina, northwestern Argentina, using the fission-track method to date tuffs interbedded in synorogenic clastic sedimentary strata

    Energy Technology Data Exchange (ETDEWEB)

    Tabbutt, K.D. (Dartmouth College, Hanover, NH (USA))

    1990-07-01

    Fission-track dates from seven volcaniclastic units allow time constraints to be placed on synorogenic clastic strata exposed along the flanks of Sierra de Famatina, northwest Argentina. Four formations are exposed along the western margin of Sierra de Famatina. The El Abra conglomerate is composed of clasts eroded from the basement exposed just to the west of Cadena de Paiman. The El Buey Formation contains sediments probably derived from the Precordillera fold and thrust belt to the west. Fission-track dates give a maximum age of 6 Ma for the deposition of both of these formations. The El Durazno Formation, deposited between 6 and 4 Ma, contains proximal volcaniclastic and other clastic rocks derived from the core of Sierra de Famatina. The Santa Florentina conglomerate was derived from the rising Sierra de Famatina and deposited in the past 4 m.y. Sierra de Famatima probably became a positive topographic feature approximately 6 Ma. Prior to that time this region was receiving fine-grained sediments from a distal fold and thrust belt and conglomerates from local basement uplifts. Minor extrusive events (Mogote Formation) coincide both spatially and temporally with deformation along the major reverse faults that control the uplift of Sierra de Famatina. Minimum mean uplift rates calculated for Sierra de Famatina are 0.8 {plus minus} 0.1 mm/yr over a 6.8 m.y. interval.

  1. Nevada Thickness of Cenozoic Deposits

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This study of gravity data from Nevada is part of a statewide analysis of mineral resources. The main objective of the gravity study were: 1) to infer the structure...

  2. High-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region, California

    Science.gov (United States)

    Ponce, D. A.; Mangan, M.; McPhee, D.

    2013-12-01

    A new high-resolution aeromagnetic survey of the Mono Basin-Long Valley Caldera region greatly enhances previous magnetic interpretations that were based on older, low-resolution, and regional aeromagnetic data sets and provides new insights into volcano-tectonic processes. The surveyed area covers a 8,750 km2 NNW-trending swath situated between the Sierra Nevada to the west and the Basin and Range Province to the east. The surveyed area includes the volcanic centers of Mono Lake, Mono-Inyo Craters, Mammoth Mountain, Devils Postpile, and Long Valley Caldera. The NW-trending eastern Sierra frontal fault zone crosses through the study area, including the active Mono Lake, Silver Lake, Hartley Springs, Laurel Creek, and Hilton Creek faults. Over 6,000 line-kilometers of aeromagnetic data were collected at a constant terrain clearance of 150 m, a flight-line spacing of 400 m, and a tie-line spacing of 4 km. Data were collected via helicopter with an attached stinger housing a magnetic sensor using a Scintrex CS-3 cesium magnetometer. In the northern part of the survey area, data improve the magnetic resolution of the individual domes and coulees along Mono Craters and a circular shaped magnetic anomaly that coincides with a poorly defined ring fracture mapped by Kistler (1966). Here, aeromagnetic data combined with other geophysical data suggests that Mono Craters may have preferentially followed a pre-existing plutonic basement feature that may have controlled the sickle shape of the volcanic chain. In the northeastern part of the survey, aeromagnetic data reveal a linear magnetic anomaly that correlates with and extends a mapped fault. In the southern part of the survey, in the Sierra Nevada block just south of Long Valley Caldera, aeromagnetic anomalies correlate with NNW-trending Sierran frontal faults rather than to linear NNE-trends observed in recent seismicity over the last 30 years. These data provide an important framework for the further analysis of the

  3. Active basement uplift as seen with cosmogenic lenses: the Sierra Pie de Palo case (Western Argentina)

    Science.gov (United States)

    Siame, L. L.; Sébrier, M.; Costa, C. H.; Ahumada, E. A.; Bellier, O.

    2013-12-01

    The Andean foreland of western Argentina (28°S-33°S) corresponds to retroarc deformations associated with the ongoing flat subduction of the Nazca plate beneath the South American lithosphere, and associated with high levels of seismic activity and crustal active faulting. To improve earthquake source identification and characterization in the San Juan region, data from seismology, structural geology and quantitative geomorphology can be integrated and combined to provide a seismotectonic model. In this model, the Andean back-arc of western Argentina has to be regarded as an obliquely converging foreland where Plio-Quaternary deformations are partitioned between strike-slip and thrust motions that are localized on the E-verging, thin-skinned Argentine Precordillera, and the W-verging thick-skinned Sierras Pampeanas, respectively. In this domain, the Sierra Pie de Palo is a key structure playing a major role in the partitioning of the Plio-Quaternary deformations. Located in the westernmost Sierras Pampeanas, the Sierra Pie de Palo forms a NNE striking, 80 km-long and 35-40 km-wide, ellipsoid range that reaches elevation as high as 3162 m. This mountain range is an actively growing basement fold associated with a high level of seismic activity (e.g., the November 23, 1977, Caucete, Mw 7.4 earthquake). To evaluate the degree of tectonic activity around the Sierra Pie de Palo, we combined a detailed morphometric analysis of the topography together with in situ-produced cosmogenic 10Be concentrations measured in (1) bedrock outcrops corresponding to the exhumed erosional regional surface, (2) surface boulders abandoned on alluvial fans deformed by active faults, and (3) in fluvial sediments sampled at the outlets of selected watersheds that drains out from the Sierra Pie de Palo. All together, our results allows: (1) assessing quantitative constraints on the rate of tectonic and denudation processes that are responsible for the active growth and erosion of the Sierra

  4. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1983-05-01

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100 0 C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites

  5. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1983-05-01

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100{sup 0}C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites.

  6. Sierra/SolidMechanics 4.48 Verification Tests Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Plews, Julia A.; Crane, Nathan K; de Frias, Gabriel Jose; Le, San; Littlewood, David John; Merewether, Mark Thomas; Mosby, Matthew David; Pierson, Kendall H.; Porter, Vicki L.; Shelton, Timothy; Thomas, Jesse David; Tupek, Michael R.; Veilleux, Michael; Xavier, Patrick G.

    2018-03-01

    Presented in this document is a small portion of the tests that exist in the Sierra / SolidMechanics (Sierra / SM) verification test suite. Most of these tests are run nightly with the Sierra / SM code suite, and the results of the test are checked versus the correct analytical result. For each of the tests presented in this document, the test setup, a description of the analytic solution, and comparison of the Sierra / SM code results to the analytic solution is provided. Mesh convergence is also checked on a nightly basis for several of these tests. This document can be used to confirm that a given code capability is verified or referenced as a compilation of example problems. Additional example problems are provided in the Sierra / SM Example Problems Manual. Note, many other verification tests exist in the Sierra / SM test suite, but have not yet been included in this manual.

  7. Region 9 Tribal Lands

    Data.gov (United States)

    U.S. Environmental Protection Agency — Dataset of all Indian Reservations in US EPA Region 9 (California, Arizona and Nevada) with some reservation border areas of adjacent states included (adjacent areas...

  8. Nevada Test Site Waste Acceptance Criteria

    International Nuclear Information System (INIS)

    U.S. Department of Energy, Nevada Operations Office, Waste Acceptance Criteria

    1999-01-01

    This document provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive and mixed waste for disposal; and transuranic and transuranic mixed waste for interim storage at the Nevada Test Site

  9. Sierra Madre Oriental in Coahuila, Mexico

    Science.gov (United States)

    2002-01-01

    This desolate landscape is part of the Sierra Madre Oriental mountain range, on the border between the Coahuila and Nuevo Leon provinces of Mexico. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on November 28, 1999. This is a false-color composite image made using shortwave infrared, infrared, and green wavelengths. The image has also been sharpened using the sensor's panchromatic band. Image provided by the USGS EROS Data Center Satellite Systems Branch

  10. High Sierra Beef Progress Update

    OpenAIRE

    Ingram, Roger

    2004-01-01

    Research similar efforts in other regions Research was completed on similar efforts in other regions. There are over 300 grass-fed beef marketing operations across the United States. Here in California, there are approximately 10. Most are selling approximately 50-60 head per year. This appears to be a marketing limit for those who produce, process, market and distribute on their own. Additional labor and space requirements for marketing, storage for dry-aging, and distribution appea...

  11. Nevada Test Site Waste Acceptance Criteria (NTSWAC)

    Energy Technology Data Exchange (ETDEWEB)

    NNSA/NSO Waste Management Project

    2008-06-01

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, Nevada Test Site Waste Acceptance Criteria (NTSWAC). The NTSWAC provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive (LLW) and LLW Mixed Waste (MW) for disposal.

  12. Nevada Test Site Waste Acceptance Criteria (NTSWAC)

    International Nuclear Information System (INIS)

    NNSA/NSO Waste Management Project

    2008-01-01

    This document establishes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, Nevada Test Site Waste Acceptance Criteria (NTSWAC). The NTSWAC provides the requirements, terms, and conditions under which the Nevada Test Site will accept low-level radioactive (LLW) and LLW Mixed Waste (MW) for disposal

  13. Geologic studies in the Sierra de Pena Blanca, Chihuahua, Mexico

    Science.gov (United States)

    Reyes-Cortes, Ignacio Alfonso

    The Sierra del Cuervo has been endowed with uranium mineralization, which has attracted many geological studies, and recently the author was part of a team with the goal of selecting a site of a radioactive waste repository. The first part of the work adds to the regional framework of stratigraphy and tectonics of the area. It includes the idea of a pull apart basin development, which justifies the local great thickness of the Cuervo Formation. It includes the regional structural frame work and the composite stratigraphic column of the Chihuahua Trough and the equivalent Cretaceous Mexican Sea. The general geologic features of the NE part of the Sierra del Cuervo are described, which include the folded ignimbrites and limestones in that area; the irregular large thicknesses of the Cuervo Formation; and the western vergence of the main folding within the area. Sanidine phenocrystals gave ages of 54.2 Ma and 51.8 Ma ± 2.3 Ma. This is the first time these dates have been reported in print. This age indicates a time before the folded structures which outcrop in the area, and 44 Ma is a date after the Cuervo Formation was folded. The Hidalgoan orogeny cycle affected the rocks between this lapse of time. Since then the area has been partially affected by three tensional overlapped stages, which resulted in the actual Basin and Range physiography. The jarosite related to the tectonic activity mineralization has been dated by the Ar-Ar method and yields an age of 9.8 Ma. This is the first report of a date of mineralization timing at Pena Blanca Uranium District in the Sierra del Cuervo. These are some of the frame work features that justify the allocation of a radioactive waste repository in the Sierra del Cuervo. An alluvial fan system within the Boquilla Colorada microbasin was selected as the best target for more detailed site assessment. The study also included the measurement of the alluvium thicknesses by geoelectric soundings; studies of petrography and weathered

  14. EcoRegion Polygons, Nevada, 2007, ECOMAP

    Data.gov (United States)

    U.S. Environmental Protection Agency — Ecoregions denote areas of general similarity in ecosystems and in the type, quality, and quantity of environmental resources. They are designed to serve as a...

  15. Fault structure and kinematics of the Long Valley Caldera region, California, revealed by high-accuracy earthquake hypocenters and focal mechanism stress inversions

    Science.gov (United States)

    Prejean, Stephanie; Ellsworth, William L.; Zoback, Mark; Waldhauser, Felix

    2002-01-01

    We have determined high-resolution hypocenters for 45,000+ earthquakes that occurred between 1980 and 2000 in the Long Valley caldera area using a double-difference earthquake location algorithm and routinely determined arrival times. The locations reveal numerous discrete fault planes in the southern caldera and adjacent Sierra Nevada block (SNB). Intracaldera faults include a series of east/west-striking right-lateral strike-slip faults beneath the caldera's south moat and a series of more northerly striking strike-slip/normal faults beneath the caldera's resurgent dome. Seismicity in the SNB south of the caldera is confined to a crustal block bounded on the west by an east-dipping oblique normal fault and on the east by the Hilton Creek fault. Two NE-striking left-lateral strike-slip faults are responsible for most seismicity within this block. To understand better the stresses driving seismicity, we performed stress inversions using focal mechanisms with 50 or more first motions. This analysis reveals that the least principal stress direction systematically rotates across the studied region, from NE to SW in the caldera's south moat to WNW-ESE in Round Valley, 25 km to the SE. Because WNW-ESE extension is characteristic of the western boundary of the Basin and Range province, caldera area stresses appear to be locally perturbed. This stress perturbation does not seem to result from magma chamber inflation but may be related to the significant (???20 km) left step in the locus of extension along the Sierra Nevada/Basin and Range province boundary. This implies that regional-scale tectonic processes are driving seismic deformation in the Long Valley caldera.

  16. Experimental Repatriation of Mountain Yellow-legged Frogs (Rana muscosa) in the Sierra Nevada of California

    Science.gov (United States)

    Fellers, Gary M.; Bradford, David F.; Pratt, David; Wood, Leslie

    2008-01-01

    In the late 1970s, Rana muscosa (mountain yellow-legged frog) was common in the Tableland area of Sequoia National Park, California where it was possible to find hundreds of tadpoles and adults around many of the ponds and lakes. Surveys in 1993-1995 demonstrated that R. muscosa was absent from more than half of all suitable habitat within the park, including the Tableland area. At that same time, R. muscosa was still common at Sixty Lake Basin, Kings Canyon National Park, 30 km to the northeast. To evaluate the potential causes for the extirpation, we repatriated R. muscosa eggs, tadpoles, subadults, and adult frogs from Sixty Lake Basin to four sites in the Tableland area in 1994 and 1995. We subsequently surveyed each release site and the surrounding area 2 - 3 times per week in 1994-1995, and intermittently in 1996-1997, to monitor the survival of all life history stages, and to detect dispersal of adults and subadults. We also monitored predation, water quality, weather, and water temperature. Our techniques for capturing, holding, transporting, and releasing R. muscosa were refined during the study, and during 1995 resulted in high initial survival rates of all life history stages. Adult frogs were anaesthetized, weighed, measured, tagged, and held in plastic boxes with wet paper towels. Tadpoles were collected and held in fiberglass screen cages set in the water at the edge of a pond. This resulted in relatively natural conditions with less crowding and good water circulation. Frogs, tadpoles, and eggs were placed in Ziploc bags for transport to the Tableland by helicopter. Short-term survival of tadpoles, subadults, and adults was high at all four release sites, tadpoles reached metamorphosis, and adult frogs were still present. However, we detected no evidence of reproduction at three sites (e.g., no new eggs or small tadpoles) and nearly all life history stages disappeared within 12 months. At the fourth site, there was limited reproduction, but it was insufficient to maintain a population. It appears that the causal factors for the demise of R. muscosa in the Tableland during the 1970s were still operating in the 1990s or that a new limiting factor has developed. Dispersal, weather, water quality, and predation do not appear to be causative agents; since fish have never been present in the portions of the watershed where we were working, they were not a factor. Observations and data are consistent with the hypotheses that chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis, and/or exposure to airborne pesticides caused both declines. However, at the time of our study, chytridiomycosis had not been described and the potentially significant role of contaminants was largely undocumented.

  17. 78 FR 24471 - Endangered and Threatened Wildlife and Plants; Endangered Status for the Sierra Nevada Yellow...

    Science.gov (United States)

    2013-04-25

    ... patterned with dark spots (Jennings and Hayes 1994, p. 74; Stebbins 2003, p. 233). These spots may be large...). Mountain yellow-legged frogs have smoother skin, generally with heavier spotting and mottling dorsally...

  18. Clearcutting and natural regeneration: management implications for the northern Sierra Nevada

    Science.gov (United States)

    Philip M. McDonald

    1983-01-01

    In the young-mature mixed-conifer and hardwood forests of north-central California, a dense and persistent hardwood understory competes with the conifers for space, nutrients, and water. Clear-cutting with intensive site preparation often is the most appropriate silvicultural regeneration method. This report, the result of 20 years of research on the Challenge...

  19. A broadcast burn in secondgrowth clearcuttings in the north central Sierra Nevada

    Science.gov (United States)

    Philip M. McDonald; Harry E. Schimke

    1966-01-01

    At the Challenge Experimental Forest, 29 acres of slash were broadcast burned on five small clearcut plots (2 to 10 acres) at a cost of $57.00 per acre. Fuel-weight measurements showed reductions of 68 to 84 percent after the burn. Modifications to plot size, shape, and orientation could reduce this cost.

  20. A climate change primer for land managers: an example from the Sierra Nevada

    Science.gov (United States)

    Toni Lyn Morelli; Maureen C. McGlinchy; Ronald P. Neilson

    2011-01-01

    Interest in location-specific climate projections is growing. To facilitate the communication of these data, we provide here an example for how to present climate information relevant at the scale of a national forest. We summarize some of the latest data on climate change projections and impacts relevant to eastern California, from the global scale to the state level...

  1. Fuel treatment effects on modeled landscape level fire behavior in the northern Sierra Nevada

    Science.gov (United States)

    J.J. Moghaddas; B.M. Collins; K. Menning; E.E.Y. Moghaddas; S.L. Stephens

    2010-01-01

    Across the western United States, decades of fire exclusion combined with past management history have contributed to the current condition of extensive areas of high-density, shade-tolerant coniferous stands that are increasingly prone to high-severity fires. Here, we report the modeled effects of constructed defensible fuel profile zones and group selection...

  2. 76 FR 9595 - Notice of Public Meetings: Sierra Front Northwestern Basin Resource Advisory Council, Nevada

    Science.gov (United States)

    2011-02-18

    ... Plant, LiDAR (Optical Remote-Sensing Technology) Virtual Tour of Hidden Cave, Hidden Cave and Grimes... proposals and RAC-hosted public comment, landscape approach/land health assessment processes, impacts to...

  3. Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California

    Directory of Open Access Journals (Sweden)

    D. R. Worton

    2011-10-01

    Full Text Available In this paper we report chemically resolved measurements of organic aerosol (OA and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX at the Blodgett Forest Research Station, California from 15 August–10 October 2007. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA. The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In situ measurements of particle phase molecular markers were dominated by secondary compounds and along with gas phase compounds could be categorized into six factors or sources: (1 aged biomass burning emissions and oxidized urban emissions, (2 oxidized urban emissions (3 oxidation products of monoterpene emissions, (4 monoterpene emissions, (5 anthropogenic emissions and (6 local methyl chavicol emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g. temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher during the first half of the campaign (15 August–12 September due to more substantial emissions of isoprene and enhanced photochemistry. The oxidation of methyl chavicol, an oxygenated terpene emitted by ponderosa pine trees, contributed similarly to OA throughout the campaign. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during the cooler conditions in the latter half of the campaign (13 September–10 October, even though emissions of the precursors were lower, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO, consistent with previous observations, while being comprised of mostly non-fossil carbon (>75%. The correlation between OA and an anthropogenic tracer does not necessarily identify the source of the carbon as being anthropogenic but instead suggests a coupling between the anthropogenic and biogenic components in the air mass that might be related to the source of the oxidant and/or the aerosol sulfate. Observations of organosulfates of isoprene and α-pinene provided evidence for the likely importance of aerosol sulfate in spite of neutralized aerosol although acidic plumes might have played a role upwind of the site. This is in contrast to laboratory studies where strongly acidic seed aerosols were needed in order to form these compounds. These compounds together represented only a minor fraction (<1% of the total OA mass, which may be the result of the neutralized aerosol at the site or because only a small number of organosulfates were quantified. The low contribution of organosulfates to total OA suggests that other mechanisms, e.g. NOx enhancement of oxidant levels, are likely responsible for the majority of the anthropogenic enhancement of biogenic secondary organic aerosol observed at this site.

  4. ANNUAL OZONE DEPOSITION TO A PONDEROSA PINE PLANTATION IN THE SIERRA NEVADA MOUNTAINS. (R826601)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Population dynamics of dwarf mistletoe on young true firs in the central Sierra Nevada, California

    Science.gov (United States)

    Robert E Scharpf; J. R. Jr. Parmeter

    1982-01-01

    Young red firs (Abies magnifica A. Murr.) and white firs (A. concolor [Gord. & Glend.] Lindl. ex Hildebr.) on the Stanislaus National Forest, California, were inoculated with seeds of dwarf mistletoe (Arceuthobium abietinum) for 5 successive years. Only 3 to 4 percent of about 7000 seeds placed on branches...

  6. Impacts of Aerosols on the Retreat of the Sierra Nevada Glaciers in California

    Science.gov (United States)

    El-Askary, H. M.; Li, J.; Ta, T. N.; Jong, A.; Zhang, X.

    2015-12-01

    Natural dust aerosol is an active component of the climate system and plays multiple roles in physical climate and bio-geo-chemical exchanges between the atmosphere, land surface and ocean. Aerosol deposition on snow is amongst the different causes of glacier retreat around the world as well as the reduction of snow albedo. We have observed a long range transport of dust and pollution aerosols from China to the U.S. In this paper we compared summer and winter seasons glacier changes between 2000 and 2013, and how the dust aerosol change over this 13 years. Multiple images, acquired from Landsat-5 TM, Landsat-7 ETM+ and Landsat-8 OLI were used in the study. The change detection analysis was employed to identify the glacier changes for two seasons. The results suggest that the glacier decreased dramatically over 13 years in both seasons.

  7. Air Quality at Devils Postpile National Monument, Sierra Nevada Mountains, California, USA

    Science.gov (United States)

    Joel D. Burley; Andrzej Bytnerowicz; Monica Buhler; Barbara Zielinska; Donald Schweizer; Ricardo Cisneros; Susan Schilling; Jennifer Chapman Varela; Mark McDaniel; Michelle Horn; Deanna Dulen

    2016-01-01

    Ambient concentrations of O3, PM2.5, NH3, NO, NO2, HNO3, SO2 and VOCs were measured at Devils Postpile National Monument (DEPO) during the summer seasons of 2013 and 2014. The measurements were impacted by the Aspen and Rim Fires in...

  8. Conceptual model of sediment processes in the upper Yuba River watershed, Sierra Nevada, CA

    Science.gov (United States)

    Curtis, J.A.; Flint, L.E.; Alpers, Charles N.; Yarnell, S.M.

    2005-01-01

    This study examines the development of a conceptual model of sediment processes in the upper Yuba River watershed; and we hypothesize how components of the conceptual model may be spatially distributed using a geographical information system (GIS). The conceptual model illustrates key processes controlling sediment dynamics in the upper Yuba River watershed and was tested and revised using field measurements, aerial photography, and low elevation videography. Field reconnaissance included mass wasting and channel storage inventories, assessment of annual channel change in upland tributaries, and evaluation of the relative importance of sediment sources and transport processes. Hillslope erosion rates throughout the study area are relatively low when compared to more rapidly eroding landscapes such as the Pacific Northwest and notable hillslope sediment sources include highly erodible andesitic mudflows, serpentinized ultramafics, and unvegetated hydraulic mine pits. Mass wasting dominates surface erosion on the hillslopes; however, erosion of stored channel sediment is the primary contributor to annual sediment yield. We used GIS to spatially distribute the components of the conceptual model and created hillslope erosion potential and channel storage models. The GIS models exemplify the conceptual model in that landscapes with low potential evapotranspiration, sparse vegetation, steep slopes, erodible geology and soils, and high road densities display the greatest hillslope erosion potential and channel storage increases with increasing stream order. In-channel storage in upland tributaries impacted by hydraulic mining is an exception. Reworking of stored hydraulic mining sediment in low-order tributaries continues to elevate upper Yuba River sediment yields. Finally, we propose that spatially distributing the components of a conceptual model in a GIS framework provides a guide for developing more detailed sediment budgets or numerical models making it an inexpensive way to develop a roadmap for understanding sediment dynamics at a watershed scale.

  9. Soil carbon storages and erosional exports along a forested denudation gradient in the Sierra Nevada, California

    Science.gov (United States)

    Yoo, K.; Wang, X.; Mudd, S. M.; Weinman, B.; Gutknecht, J.; Gabet, E. J.

    2017-12-01

    Eroding uplands not only provide physically mixed soil zones where OC and minerals actively interact but also are the significant sources of suspended sediments and organic carbon (OC) to rivers. Here our goal is to quantify the extents that erosion affects soils' capacities to store OC in different degrees of mineral-association and to facilitate the exports of minerals that might capture OC on their reactive surfaces. We examined a tributary basin to the Middle Folk Feather River in California, where knickpoint migration has created a series of hillslopes with erosion rates varying from 35 to 250 mm kyr-1. Other than erosion rates, the studied hillslopes within the tributary basin shared similar environmental factors. Soil samples were collected from select hillslopes that differ in their relative positions to knikpoints and were subject to size and density fractionation. Despite the substantial difference in erosion rates, concentrations of particulate OC (POC) and mineral-associated OC (MOC) and soil thickness varied little. Instead, considerable increase in coarse rock contents positively associated with erosion rate was responsible for the reduction of soil OC inventories by 37% with increasing erosion rate. In contrast to consistent MOC concentrations across the erosion gradient, clay contents in soils are negatively correlated with erosion rates. This seemingly contradictory result, however, is consistent with BET mineral specific surface area that remains insensitive to erosion rates. OC coverage on mineral surface was found to be less than affects the soil carbon cycle.

  10. Predicted fire behavior and societal benefits in three eastern Sierra Nevada vegetation types

    Science.gov (United States)

    C.A. Dicus; K. Delfino; D.R. Weise

    2009-01-01

    We investigated potential fire behavior and various societal benefits (air pollution removal, carbon sequestration, and carbon storage) provided by woodlands of pinyon pine (Pinus monophylla) and juniper (Juniperus californica), shrublands of Great Basin sagebrush (Artemisia tridentata) and rabbitbrush (Ericameria nauseosa...

  11. Nonlocal Sediment Transport on Steep Lateral Moraines, Eastern Sierra Nevada, California, USA

    Science.gov (United States)

    Doane, Tyler H.; Furbish, David Jon; Roering, Joshua J.; Schumer, Rina; Morgan, Daniel J.

    2018-01-01

    Recent work has highlighted the significance of long-distance particle motions in hillslope sediment transport. Such motions imply that the flux at a given hillslope position is appropriately described as a weighted function of surrounding conditions that influence motions reaching the given position. Although the idea of nonlocal sediment transport is well grounded in theory, limited field evidence has been provided. We test local and nonlocal formulations of the flux and compare their ability to reproduce land surface profiles of steep moraines in California. We show that nonlocal and nonlinear models better reproduce evolved land surface profiles, notably the amount of lowering and concavity near the moraine crest and the lengthening and straightening of the depositional apron. The analysis provides the first estimates of key parameters that set sediment entrainment rates and travel distances in nonlocal formulations and highlights the importance of correctly specifying the entrainment rate when modeling land surface evolution. Moraine evolution associated with nonlocal and nonlinear transport formulations, when described in terms of the evolution of the Fourier transform of the moraine surface, displays a distinct behavior involving growth of certain wave numbers, in contrast to the decay of all wave numbers associated with linear transport. Nonlinear and nonlocal formulations share key mathematical elements yielding a nonlinear relation between the flux and the land surface slope.

  12. Historical and contemporary distributions of carnivores in forests of the Sierra Nevada, California, USA

    Science.gov (United States)

    William J Zielinski; Richard L Truex; Fredrick V. Schlexer; Lori A. Campbell; Carlos Caroll

    2005-01-01

    Malammalian carnivores are considered particularly sensitive indicators of environmental change. Information on the distribution of carnivores from the early 1900s provides a unique opportunity to evaluate changes in their distributions over a 75-year period during which the influence of human uses of forest resources in California greatly increased. We present...

  13. Soil moisture response to snowmelt and rainfall in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Roger C. Bales; Jan W. Hopmans; Anthony T. O’Geen; Matthew Meadows; Peter C. Hartsough; Peter Kirchner; Carolyn T. Hunsaker; Dylan. Beaudette

    2011-01-01

    Using data from a water-balance instrument cluster with spatially distributed sensors we determined the magnitude and within-catchment variability of components of the catchment-scale water balance, focusing on the relationship of seasonal evapotranspiration to changes in snowpack and soil moisture storage. Co-located, continuous snow depth and soil moisture...

  14. Accumulation of pesticides in pacific chorus frogs (Pseudacris regilla) from California's Sierra Nevada Mountains, USA

    Science.gov (United States)

    Smalling, Kelly L.; Fellers, Gary M.; Kleeman, Patrick M.; Kuivila, Kathryn

    2013-01-01

    Pesticides are receiving increasing attention as potential causes of amphibian declines, acting singly or in combination with other stressors, but limited information is available on the accumulation of current-use pesticides in tissue. The authors examined potential exposure and accumulation of currently used pesticides in pond-breeding frogs (Pseudacris regilla) collected from 7 high elevations sites in northern California. All sites sampled are located downwind of California's highly agricultural Central Valley and receive inputs of pesticides through precipitation and/or dry deposition. Whole frog tissue, water, and sediment were analyzed for more than 90 current-use pesticides and pesticide degradates using gas chromatography–mass spectrometry. Two fungicides, pyraclostrobin and tebuconazole, and one herbicide, simazine, were the most frequently detected pesticides in tissue samples. Median pesticide concentration ranged from 13 µg/kg to 235 µg/kg wet weight. Tebuconazole and pyraclostrobin were the only 2 compounds observed frequently in frog tissue and sediment. Significant spatial differences in tissue concentration were observed, which corresponded to pesticide use in the upwind counties. Data generated indicated that amphibians residing in remote locations are exposed to and capable of accumulating current-use pesticides. A comparison of P. regilla tissue concentrations with water and sediment data indicated that the frogs are accumulating pesticides and are potentially a more reliable indicator of exposure to this group of pesticides than either water or sediment.

  15. Restoring surface fire stabilizes forest carbon under extreme fire weather in the Sierra Nevada

    Science.gov (United States)

    Daniel J. Krofcheck; Matthew D. Hurteau; Robert M. Scheller; E. Louise Loudermilk

    2017-01-01

    Climate change in the western United States has increased the frequency of extreme fire weather events and is projected to increase the area burned by wildfire in the coming decades. This changing fire regime, coupled with increased high-severity fire risk from a legacy of fire exclusion, could destabilize forest carbon (C), decrease net ecosystem exchange (...

  16. Non-native fish introductions and the reversibility of amphibian declines in the Sierra Nevada

    Science.gov (United States)

    Roland A. Knapp

    2004-01-01

    Amphibians are declining worldwide for a variety of reasons, including habitat alteration, introduction of non-native species, disease, climate change, and environmental contaminants. Amphibians often play important roles in structuring ecosystems, and, as a result, amphibian population declines or extinctions are likely to affect other trophic levels (Matthews and...

  17. Forest biomass diversion in the Sierra Nevada: Energy, economics and emissions

    Science.gov (United States)

    Bruce Springsteen; Thomas Christofk; Robert A. York; Tad Mason; Stephen Baker; Emily Lincoln; Bruce Hartsough; Takuyuki Yoshioka

    2015-01-01

    As an alternative to open pile burning, use of forest wastes from fuel hazard reduction projects at Blodgett Forest Research Station for electricity production was shown to produce energy and emission benefits: energy (diesel fuel) expended for processing and transport was 2.5% of the biomass fuel (energy equivalent); based on measurements from a large pile...

  18. Agro-climatology of the Colombian Caribbean Region

    International Nuclear Information System (INIS)

    Claro Rizo, Francisco

    1997-01-01

    The agro-meteorology has for object the knowledge of the physical environment where the plants and the animals are developed, to make of him a better use, with the primordial purpose of optimizing the agricultural production. The climatology of the Caribbean Region, it is governed by the zonal processes of thermal and dynamic convection, together with the effect of the Inter-tropical Confluence Area (ITC) however, this extensive plain of the Colombian Caribbean, to be interrupted by the Sierra Nevada of Santa Marta and framed by the Caribbean Sea and the Andean mountain ranges, it makes that big differences are presented in their climatic regime. In this study, climatic elements are analyzed in the region, such as the precipitation, the temperature and the relative humidity of the air, the radiation and the solar shine, the speed of the wind and the potential evapo-perspiration, besides the calculation of the hydraulic balances, those which as integrative of the agriculture-climatic aspects, they serve as base to make the climatic classifications, to know the growth periods and to calculate the potential water demands, fundamental parameters in the planning of the agricultural activities. With these results they stand out the diverse climates in the region, represented in climatic areas from arid until per-humid offer a wide range for the requirements of the different species that are used in the agricultural exploitations

  19. Nevada local government revenues analysis

    International Nuclear Information System (INIS)

    1988-06-01

    This report analyzes the major sources of revenue for Nevada local government for purposes of estimating the impacts associated with the siting of a nuclear waste repository at Yucca Mountain. Each major revenue source is analyzed separately to identify relationships between the economic or demographic base, the revenue base and the revenues generated. Trends and changes in the rates and/or base are highlighted. A model is developed for each component to allow impact estimation. This report is a companion to the report Nevada State Revenues Analysis

  20. Discovery of the Sierra Pintada uranium district, Mendoza Province, Argentina

    International Nuclear Information System (INIS)

    Rodrigo, F.; Belluco, A.E.

    1981-01-01

    Since 1956, uranium-bearing minerals have been known to exist in Sierra Pintada, Mendoza Province, Argentina. Based on paragenetic considerations, a first radiometric prospection was carried out, leading to the discovery of two groups of anomalies (Puesto Agua del Toro and Cuesta de los Terneros), such as vein-type deposits, with uraninite and 'yellow minerals' and one sandstone-type deposit (Puesto La Josefa), related to sediments with carbon trash. Some recent geological research and surveys in the area, and a reduced drilling programme carried out on selected anomalies, led to reinterpretation of the potential of the area. Furthermore, and as a result of an airborne radiometric prospection performed in mid-1968, numerous anomalies have been discovered. The main constellation of anomalies, along the flanks of the El Tigre Brachyanticline, occurs in sandstones of Permian age. Explored by 80 000 m of drilling, they have shown the existence of several peneconcordant lens-shaped ore bodies of economic size, with uranophane on the surface and prevailing uraninite and some brannerite, coffinite and davidite below the water table. Reserves exceed 20 000 tonnes of U 3 O 8 . A new regional programme with a 4-km drill-grid initiated in 1978 led to the discovery of new ore bodies which are at present being evaluated. The alternatives and discontinuities during the development of the district, the prospecting and exploration techniques employed, and the results achieved in the different stages of the operation are discussed in detail. This case history attempts to illustrate the developing philosophy which was successfully applied in Sierra Pintada, with emphasis on the following points: (a) the need for adequate geological knowledge of the area; (b) the advantage of a massive survey (in this case, air survey); (c) the necessity for exploration (drilling) in order to define the anomalies and make their evaluation possible; and (d) the convenience of extending exploration

  1. A lineament analysis of Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Perry, J.J.

    1988-01-01

    The Nuclear Waste Policy Act of 1982 was signed into law on January 7, 1983. It specifies procedures for the Department of Energy in the selection of a high level nuclear waste repository. Federal Environmental Protection Agency standards require adequate isolation of waste from the biosphere for 10,000 years. The law considers such geologic factors as tectonic stability, igneous activity, hydrologic conditions and natural resources to be of primary concern. Yucca Mountain in southern Nevada is one of three sites selected for further consideration in the site characterization process. The Nuclear Waste Project Office (NWPO) within the Agency for Nuclear Projects of the State of Nevada is conducting an independent scientific assessment of the proposed site. The remote sensing technical assessment is one of seven task groups conducting review and research into the suitability of Yucca Mountain. The study undertaken by the Remote Sensing Group was that of a lineament analysis with regard to the site's structural relationship within a regional tectonic framework. Lineaments mapped from synoptic imagery may prove to represent structural zones of weakness. These zones may provide pathways for the infiltration of groundwater, conduits for the extrusion of magma or be reactivated as stress conditions change. This paper describes the methodology for a lineament analysis of the Yucca Mountain area

  2. Mixed waste disposal facility at the Nevada Test Site

    International Nuclear Information System (INIS)

    Dickman, P.T.; Kendall, E.W.

    1987-01-01

    In 1984, a law suit brought against DOE resulted in the requirement that DOE be subject to regulation by the state and US Environmental Protection Agency (EPA) for all hazardous wastes, including mixed wastes. Therefore, all DOE facilities generating, storing, treating, or disposing of mixed wastes will be regulated under the Resource Conservation and Recovery Act (RCTA). In FY 1985, DOE Headquarters requested DOE low-level waste (LLW) sites to apply for a RCRA Part B Permit to operate radioactive mixed waste facilities. An application for the Nevada Test Site (NTS) was prepared and submitted to the EPA, Region IX in November 1985 for review and approval. At that time, the state of Nevada had not yet received authorization for hazardous wastes nor had they applied for regulatory authority for mixed wastes. In October 1986, DOE Nevada Operations Office was informed by the Rocky Flats Plant that some past waste shipments to NTS contained trace quantities of hazardous substances. Under Colorado law, these wastes are defined as mixed. A DOE Headquarters task force was convened by the Under Secretary to investigate the situation. The task force concluded that DOE has a high priority need to develop a permitted mixed waste site and that DOE Nevada Operations Office should develop a fast track project to obtain this site and all necessary permits. The status and issues to be resolved on the permit for a mixed waste site are discussed

  3. Residential Energy Efficiency Potential: Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Eric J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-16

    Energy used by Nevada single-family homes that can be saved through cost-effective improvements. Prepared by Eric Wilson and Noel Merket, NREL, and Erin Boyd, U.S. Department of Energy Office of Energy Policy and Systems Analysis.

  4. Structure of the Alpujarrides on the southern and eastern border of the Sierra de Lújar

    Directory of Open Access Journals (Sweden)

    Tubía, J. M.

    1990-08-01

    Full Text Available The Alpujarride complex located to the South of the Sierra Nevada and extending between Motril and Adra is formed of five nappes, which in ascending order are: Lújar, Cástaras, Alcázar, Murtas and Adra. These five nappes display a structure that is the result of several overlapping events. Firstly, they reflect a process of ductile shearing associated with a mylonitic foliation and a mylonitic lineation with a N4üo E average orientation. Following this, an episode of translation towards the North has been recorded; this occurred under more superficial conditions and developed gouges and fault breccias. Associated with this episode are locally developed folds, which did not give rise to a mineral blastesis. Afterwards, the late deformations occurred, affecting the whole ofthe ensemble. Of these, the most important are those that originated folds with a N-S axis, verging towards the West and the normal faults. The extensional faults towards the South would be encompassed in this sectionEl Complejo Alpujárride situado al Sur de Sierra Nevada y comprendido entre Motril y Adra, está formado por cinco mantos que son, en orden ascendente: Lújar, Cástaras, Alcázar, Murtas y Adra. Estos cinco mantos presentan una estructuración que es el resultado de varios acontecimientos superpuestos. En primer lugar, reflejan un proceso de cizallamiento dúctil hacia el NE, que lleva asociado una foliación milonítica, de orientación media N4üo E. A continuación se ha registrado un episodio de traslaciones hacia el Norte, en condiciones más superficiales, que desarrolla brechas y harinas de falla. Asociado a este episodio se desarrollan localmente pliegues, que no dan lugar a una blastesis mineral. Con posterioridad se producen las deformaciones tardías, que afectan a todo el conjunto. De ellas, las más sobresalientes son las que originan pliegues de eje N-S, vergentes al Oeste y las fallas normales. Las fallas extensionales hacia el Sur quedar

  5. Final Scientific/Technical Report – DE-EE0002960 Recovery Act. Detachment faulting and Geothermal Resources - An Innovative Integrated Geological and Geophysical Investigation of Pearl Hot Spring, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Stockli, Daniel F. [Univ. of Texas, Austin, TX (United States)

    2015-11-30

    The Pearl Host Spring Geothermal Project funded by the DoE Geothermal Program was a joint academic (KU/UT & OU) and industry collaboration (Sierra and Ram Power) to investigate structural controls and the importance of low-angle normal faults on geothermal fluid flow through a multifaceted geological, geophysical, and geochemical investigation in west-central Nevada. The study clearly showed that the geothermal resources in Clayton Valley are controlled by the interplay between low-angle normal faults and active deformation related to the Walker Lane. The study not only identified potentially feasible blind geothermal resource plays in eastern Clayton Valley, but also provide a transportable template for exploration in the area of west-central Nevada and other regional and actively-deforming releasing fault bends. The study showed that deep-seated low-angle normal faults likely act as crustal scale permeability boundaries and could play an important role in geothermal circulation and funneling geothermal fluid into active fault zones. Not unique to this study, active deformation is viewed as an important gradient to rejuvenated fracture permeability aiding the long-term viability of blind geothermal resources. The technical approach for Phase I included the following components, (1) Structural and geological analysis of Pearl Hot Spring Resource, (2) (U-Th)/He thermochronometry and geothermometry, (3) detailed gravity data and modeling (plus some magnetic and resistivity), (4) Reflection and Refraction Seismic (Active Source), (5) Integration with existing and new geological/geophysical data, and (6) 3-D Earth Model, combining all data in an innovative approach combining classic work with new geochemical and geophysical methodology to detect blind geothermal resources in a cost-effective fashion.

  6. Finding Spectral Patterns in Bark Beetle Infestations in the Sierra National Forest Using Landsat and AVIRIS Imagery

    Science.gov (United States)

    Heck, M. D.; Roberts, D. A.; Miller, D. L.; Tane, Z.

    2016-12-01

    Under normal circumstances, the bark beetles of the Sierra Nevada conifer forests are vital to ecosystem health; by eliminating weak trees, they allow other plants to grow in the space left behind, provide homes for various animals, and enrich the soil. However, climate change is putting these ecosystems at risk: warmer winters allow bark beetles to be active and breed year-round, and the severe drought conditions currently present in California leave otherwise healthy trees unable to defend against attacks. In this study, we used Google Earth and Landsat-8 imagery of the Sierra National Forest to locate trees that had been damaged by bark beetles between the summers of 2015 and 2016. Additionally, we used an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) image from summer of 2015 to look for a difference in the spectra of consistently healthy trees compared to spectra of trees which appeared healthy in 2015 but died in 2016. We found that healthy trees were consistently brighter across the spectrum than dying trees. Comparisons using t-tests were made between elevations, slopes, aspects, and spectral indices of a form (Band 1 - Band 2)/(Band 1 + Band 2) on our AVIRIS data. While we were unable to find any specific indices which indicate beetle kills, wavelengths in the ranges of 400-500 and 2200-2500 nanometers showed the most sensitivity when the brightness difference was scaled and removed.

  7. Structural Evolution of the East Sierra Valley System (Owens Valley and Vicinity, California: A Geologic and Geophysical Synthesis

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    Richard J. Blakely

    2013-04-01

    Full Text Available The tectonically active East Sierra Valley System (ESVS, which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm, which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3–3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

  8. Structural evolution of the east Sierra Valley system (Owens Valley and vicinity), California: a geologic and geophysical synt