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Nonpoint source pollution is the leading cause of the U.S.’s water quality problems. One important component of nonpoint source pollution control is an understanding of what and how watershed-scale conditions influence ambient water quality. This paper investigated the use of spatial regression to evaluate the impacts of watershed characteristics on stream NO3NO2-N concentration in the Cedar River Watershed, Iowa. An Arc Hydro geodatabase was constructed to organize various datasets on the watershed. Spatial regression models were developed to evaluate the impacts of watershed characteristics on stream NO3NO2-N concentration and predict NO3NO2-N concentration at unmonitored locations. Unlike the traditional ordinary...
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1 Univariate, multivariate, and geostatistical techniques were used to quantify the scale and degree of soil variability around individual perennial sagebrush (Artemisia tridentata ssp. vaseyana) and bluebunch wheatgrass (Pseudoroegneria spicata ssp. spicata) plants. This variability was then compared to that found across the larger sagebrush-steppe site. Samples were taken every metre in a 10-m $\times$ 12-m grid and every 12.5 cm in nine nested 0.5-m $\times$ 0.5-m grids containing at least one Artemisia shrub or Pseudoroegneria tussock (362 total samples). The 11 soil properties measured were organic matter, pH, water content, live root mass, microbial respiration, net N mineralization, nitrification potential,...
Desert plants can influence the pattern of resources in soil resulting in small-scale enriched zones. Although conceptually simple, the shape, size, and orientation of these "resource islands" are difficult to study in detail using conventional sampling regimes. To demonstrate and alternative approach, we sampled soil under and around individual Artemisia tridentata (sagebrush), a dominant shrub of cool desert environments, and analyzed the samples with univariate statistics and geostatistics. Univariate Halvorson, Jonathan J, Harvey Bolton Jr, Jeffrey L Smith, and Richard E Rossi. ?Geostatistical analysis of resource islands under Artemisia tridentata in the shrub-steppe.? Western North American Naturalist 54,...
Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/joc.4127/abstract): Gridded topoclimatic datasets are increasingly used to drive many ecological and hydrological models and assess climate change impacts. The use of such datasets is ubiquitous, but their inherent limitations are largely unknown or overlooked particularly in regard to spatial uncertainty and climate trends. To address these limitations, we present a statistical framework for producing a 30-arcsec (∼800-m) resolution gridded dataset of daily minimum and maximum temperature and related uncertainty from 1948 to 2012 for the conterminous United States. Like other datasets, we use weather station data and elevation-based predictors of temperature,...
As the population and industrial infrastructure of the United States continue to grow, the demand for water and the need to forecast water resources accurately are intensifying. Hence, the National Weather Service maintains a set of conceptual, continuous, hydrologic simulation models used to generate extended streamflow predictions, water supply outlooks and flood forecasts that are the basis for major water management and disaster emergency services decisions for the United States. A vital component of the hydrologic simulation models is a snow accumulation and ablation model that uses observed temperature and precipitation data to simulate snow cover conditions. The simulated model states are updated throughout...
The R factor, an index of rainfall erosivity in the universal soil loss equation (USLE), fundamentally governs water related soil loss from agricultural plots and is based on well studied empirical relations. Soil particles and adsorbed contaminants from agricultural runoff inevitably end up in water-courses and ultimately the Great Lakes system, disturbing natural habitat, reducing water clarity and quality. We here use over 22 years of records containing hourly precipitation recordings for 453 meteorological-recording sites in Ontario, southwestern Quebec, Michigan, Ohio, Pennsylvania, and New York to estimate the R factor surrounding the lower Laurentian Great Lakes. We generate annual and monthly R factor maps...
Desert plants can influence the pattern of resources in soil resulting in small-scale enriched zones. Although conceptually simple, the shape, size, and orientation of these "resource islands" are difficult to study in detail using conventional sampling regimes. To demonstrate and alternative approach, we sampled soil under and around individual Artemisia tridentata (sagebrush), a dominant shrub of cool desert environments, and analyzed the samples with univariate statistics and geostatistics. Univariate statistics revealed that soil variables like total inorganic-N, soluble-C, and microbial biomass-C were distributed with highest mean values within about 25 cm of the plant axis and significantly lower mean values...
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Well construction data for 11,917 domestic and 2,390 public-supply wells in the Central Valley were compiled as part of the U.S. Geological Survey (USGS) National Water Quality Assessment Project (NAWQA) and California State Water Resources Control Board (SWRCB) Groundwater Ambient Monitoring and Assessment Program Priority Basin Project (GAMA-PBP). Data were compiled for wells reported in the USGS National Water Information System (NWIS) database and from well information reported to the SWRCB Department of Drinking Water (SWRCB-DDW). Driller’s log data were transcribed from scanned images of well completion reports filed with California Department of Water Resources (DWR). The wells reported in this data release...
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The grizzly bear distribution boundary delineates the estimated geographic extent of occupied range of the Yellowstone grizzly bear population for the period 2000-2014. The distribution boundary was generated to provide reliable estimations of grizzly bear occupancy throughout time and for use as a monitoring tool in grizzly bear management and conservation. The boundary was delineated by the Interagency Grizzly Bear Study Team (IGBST) using an interpolation method based on grizzly bear telemetry and GPS locations as well as verified observations and signs of grizzly bears inside the Greater Yellowstone ecosystem during 2000 to 2014.
Variability in atmospheric deposition across the Rocky Mountains is influenced by elevation, slope, aspect, and precipitation amount and by regional and local sources of air pollution. To improve estimates of deposition in mountainous regions, maps of average annual atmospheric deposition loadings of nitrate, sulfate, and acidity were developed for the Rocky Mountains by using spatial statistics. A parameter-elevation regressions on independent slopes model (PRISM) was incorporated to account for variations in precipitation amount over mountainous regions. Chemical data were obtained from the National Atmospheric Deposition Program/National Trends Network and from annual snowpack surveys conducted by the US Geological...
We demonstrate new multi-phase, multi-scale approaches for sampling and modeling native and exotic plant species to predict the spread of invasive species and aid in control efforts. Our test site is a 54,000-ha portion of Rocky Mountain National Park, Colorado, USA. This work is based on previous research wherein we developed vegetation sampling techniques to identify hot spots of diversity, important rare habitats, and locations of invasive plant species. Here we demonstrate statistical modeling tools to rapidly assess current patterns of native and exotic plant species to determine which habitats are most vulnerable to invasion by exotic species. We use stepwise multiple regression and modified residual kriging...
    map background search result map search result map Geostatistical Patterns of Soil Heterogeneity Around Individual Perennial Plants Spatial Point Data Sets and Interpolated Surfaces of Well Construction Characteristics for Domestic and Public Supply Wells in the Central Valley, California, USA Distribution of the Yellowstone Grizzly Bear (2000-2014) Geostatistical Patterns of Soil Heterogeneity Around Individual Perennial Plants Distribution of the Yellowstone Grizzly Bear (2000-2014) Spatial Point Data Sets and Interpolated Surfaces of Well Construction Characteristics for Domestic and Public Supply Wells in the Central Valley, California, USA