Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Results

164 results.

Alternate formats: Download search results as RIS  |  CSV | TSV | Excel  |  RSS feed based on this search  |  JSON version of this page of results

Page 3, results 51 - 75

Show results on a map

Publication Extents

Not all publications have extents, not all extents are completely accurate
Investigating the mixing efficiencies of liquid-to-liquid chemical injection manifolds for aquatic invasive species management
Thomas J. Zolper, Aaron R. Cupp, David L. Smith
2018, Journal of Fluids Engineering (141) 1-14
Aquatic invasive species (AIS) have spread throughout the United States via major rivers and tributaries. Locks and dams positioned along affected waterways, specifically lock chambers, are being evaluated as potential management sites to prevent further expansion into new areas. Recent research has shown that infusion of chemicals (e.g., carbon dioxide)...
Implicit decision framing as an unrecognized source of confusion in endangered species classification
Jonathan Cummings, Sarah J. Converse, David R. Smith, Steve Morey, Michael C. Runge
2018, Conservation Biology (32) 1246-1254
Legal classification of species requires scientific and values‐based components, and how those components interact depends on how people frame the decision. Is classification a negotiation of trade‐offs, a decision on how to allocate conservation efforts, or simply a comparison of the biological status of a species to a legal standard?...
Using interviews and biological sign surveys to infer seasonal use of forested and agricultural portions of a human-dominated landscape by Asian elephants in Nepal
Babu Ram Lamichhane, Naresh Subedi, Chiranjibi Prasad Pokheral, Maheshwar Dhakal, Krishna Prasad Acharya, Narendra Man Babu Pradhan, James L. David Smith, Sabita Malla, Bishnu Singh Thakuri, Charles B. Yackulic
2018, Ethology Ecology and Evolution (30) 331-347
Understanding how wide-ranging animals use landscapes in which human use is highly heterogeneous is important for determining patterns of human–wildlife conflict and designing mitigation strategies. Here, we show how biological sign surveys in forested components of a human-dominated landscape can be combined with human interviews in agricultural portions of a...
Development of a species status assessment process for decisions under the U.S. Endangered Species Act
David R. Smith, Nathan L. Allan, Conor P. McGowan, Jennifer A. Szymankski, Susan R. Oetker, Heather M. Bell
2018, Journal of Fish and Wildlife Management (9) 302-320
Decisions under the U.S. Endangered Species Act (ESA) require scientific input on the risk that the species will become extinct. A series of critiques on the role of science in ESA decisions have called for improved consistency and transparency in species risk assessments and clear distinctions between science input and...
Chemical elements in the environment: multi-element geochemical datasets from continental to national scale surveys on four continents
Patrice de Caritat, Clemens Reimann, David B. Smith, Xueqiu Wang
2017, Applied Geochemistry (89) 150-159
During the last 10-20 years, Geological Surveys around the world have undertaken a major effort towards delivering fully harmonized and tightly quality-controlled low-density multi-element soil geochemical maps and datasets of vast regions including up to whole continents. Concentrations of between 45 and 60 elements commonly have been determined in a...
Productivity and CO2 exchange of Great Plains ecoregions. I. Shortgrass steppe: Flux tower estimates
Tagir G. Gilmanov, Jack A. Morgan, Niall P. Hanan, Bruce K. Wylie, Nithya Rajan, David P. Smith, Daniel M. Howard
2017, Rangeland Ecology and Management (70) 700-717
The shortgrass steppe (SGS) occupies the southwestern part of the Great Plains. Half of the land is cultivated, but significant areas remain under natural vegetation. Despite previous studies of the SGS carbon cycle, not all aspects have been completely addressed, including gross productivity, ecosystem respiration, and ecophysiological parameters. Our analysis...
A process to estimate net infiltration using a site-scale water-budget approach, Rainier Mesa, Nevada National Security Site, Nevada, 2002–05
David W. Smith, Michael T. Moreo, C. Amanda Garcia, Keith J. Halford, Joseph M. Fenelon
2017, Scientific Investigations Report 2017-5078
This report documents a process used to estimate net infiltration from precipitation, evapotranspiration (ET), and soil data acquired at two sites on Rainier Mesa. Rainier Mesa is a groundwater recharge area within the Nevada National Security Site where recharged water flows through bedrock fractures to a deep (450 meters)...
A projection of lesser prairie chicken (Tympanuchus pallidicinctus) populations range-wide
Jonathan W. Cummings, Sarah J. Converse, Clinton T. Moore, David R. Smith, Clay T. Nichols, Nathan L. Allan, Chris M. O'Meilia
2017, Open-File Report 2017-1071
We built a population viability analysis (PVA) model to predict future population status of the lesser prairie-chicken (Tympanuchus pallidicinctus, LEPC) in four ecoregions across the species’ range. The model results will be used in the U.S. Fish and Wildlife Service's (FWS) Species Status Assessment (SSA) for the LEPC. Our...
Optimization of decision rules for hydroelectric operation to reduce both eel mortality and unnecessary turbine shutdown: A search for a win-win solution
David R. Smith, Paul L. Fackler, Sheila M. Eyler, Laura Villegas, Stuart A. Welsh
2017, Rivers Research and Applications (33) 1279-1285
Worldwide populations of freshwater eels have declined with one of the contributing causes related to mortality during passage through hydropower turbines. An inherent trade‐off underlies turbine management where the competing demand for more hydropower comes at the expense of eel survival. A win–win solution exists when an option performs better...
Group inverse sampling: An economical approach to inverse sampling
Bardia Panahbehagh, David R. Smith
2017, Environmetrics (28)
Inverse sampling is an adaptive design in the sense that the final sampling effort during a search for rare events will depend on what is found during the survey. Conventional inverse sampling (CIS) designs successively select individual sampling units to find, for example, the k th rare event. In real...
The interacting roles of climate, soils, and plant production on soil microbial communities at a continental scale
Mark P. Waldrop, JoAnn M. Holloway, David B. Smith, Martin B. Goldhaber, R. E. Drenovsky, K. M. Scow, R. Dick, Daniel M. Howard, Bruce K. Wylie, James B. Grace
2017, Ecology (98) 1957-1967
Soil microbial communities control critical ecosystem processes such as decomposition, nutrient cycling, and soil organic matter formation. Continental scale patterns in the composition and functioning of microbial communities are related to climatic, biotic, and edaphic factors such as temperature and precipitation, plant community composition, and soil carbon, nitrogen, and pH....
Developing a landscape‐scale, multi‐species, and cost‐efficient conservation strategy for imperilled aquatic species in the Upper Tennessee River Basin, USA
David R. Smith, Robert S. Butler, Jess W Jones, Catherine M Gatenby, Roberta Hylton, Mary Parkin, Cindy Schulz
2017, Aquatic Conservation: Marine and Freshwater Ecosystems (27) 1224-1239
Strategic conservation of imperilled species faces several major challenges including uncertainty in species response to management actions, budgetary constraints that limit options, and the need to scale expected conservation benefits from local to landscape levels and from single to multiple species.A structured decision‐making process was applied to address these...
Pyrogenic carbon distribution in mineral topsoils of the northeastern United States
Verena Jauss, Patrick J. Sullivan, Jonathan Sanderman, David B. Smith, Johannes Lehmann
2017, Geoderma (296) 69-78
Due to its slow turnover rates in soil, pyrogenic carbon (PyC) is considered an important C pool and relevant to climate change processes. Therefore, the amounts of soil PyC were compared to environmental covariates over an area of 327,757 km2 in the northeastern United States in order to understand the controls...
Conservation status of the American horseshoe crab, (Limulus polyphemus): A regional assessment
David R. Smith, H. Jane Brockmann, Mark A. Beekey, Tim L. King, Michael J. Millard, Jaime Zaldívar-Rae
2017, Reviews in Fish Biology and Fisheries (27) 135-175
Horseshoe crabs have persisted for more than 200 million years, and fossil forms date to 450 million years ago. The American horseshoe crab (Limulus polyphemus), one of four extant horseshoe crab species, is found along the Atlantic coastline of North America ranging from Alabama to Maine, USA with...
Nutrient processes at the stream-lake interface for a channelized versus unmodified stream mouth
Richard G. Niswonger, Ramon C. Naranjo, David Smith, James E. Constantz, Kip K. Allander, Donald O. Rosenberry, Bethany Neilson, Michael R. Rosen, David A. Stonestrom
2017, Water Resources Research (53) 237-256
Inorganic forms of nitrogen and phosphorous impact freshwater lakes by stimulating primary production and affecting water quality and ecosystem health. Communities around the world are motivated to sustain and restore freshwater resources and are interested in processes controlling nutrient inputs. We studied the environment where streams flow into lakes, referred...
Downstream passage and impact of turbine shutdowns on survival of silver American Eels at five hydroelectric dams on the Shenandoah River
Sheila Eyler, Stuart A. Welsh, David R. Smith, Mary Rockey
2016, Transactions of the American Fisheries Society (145) 964-976
Hydroelectric dams impact the downstream migrations of silver American Eels Anguilla rostrata via migratory delays and turbine mortality. A radiotelemetry study of American Eels was conducted to determine the impacts of five run-of-the-river hydroelectric dams located over a 195-km stretch of the Shenandoah River, Virginia–West Virginia, during fall 2007–summer 2010....
Occurrence, distribution, and volume of metals-contaminated sediment of selected streams draining the Tri-State Mining District, Missouri, Oklahoma, and Kansas, 2011–12
D. Charlie Smith
2016, Scientific Investigations Report 2016-5144
Lead and zinc were mined in the Tri-State Mining District (TSMD) of southwest Missouri, northeast Oklahoma, and southeast Kansas for more than 100 years. The effects of mining on the landscape are still evident, nearly 50 years after the last mine ceased operation. The legacies of mining are the mine...
Quantifying seepage using heat as a tracer in selected irrigation canals, Walker River Basin, Nevada, 2012 and 2013
Ramon C. Naranjo, David W. Smith
2016, Scientific Investigations Report 2016-5133
The Walker River is an important source of water for western Nevada. The river provides water for agriculture and recharge to local aquifers used by several communities. Farmers began diverting water from the Walker River in the 1860s to support growing agricultural development. Over time, the reduced inflows into...
Construction of a groundwater-flow model for the Big Sioux Aquifer using airborne electromagnetic methods, Sioux Falls, South Dakota
Joshua F. Valder, Gregory C. Delzer, Janet M. Carter, Bruce D. Smith, David V. Smith
2016, Fact Sheet 2016-3075
The city of Sioux Falls is the fastest growing community in South Dakota. In response to this continued growth and planning for future development, Sioux Falls requires a sustainable supply of municipal water. Planning and managing sustainable groundwater supplies requires a thorough understanding of local groundwater resources. The Big Sioux...
Groundwater-level change and evaluation of simulated water levels for irrigated areas in Lahontan Valley, Churchill County, west-central Nevada, 1992 to 2012
David W. Smith, Susan G. Buto, Toby L. Welborn
2016, Scientific Investigations Report 2016-5045
The acquisition and transfer of water rights to wetland areas of Lahontan Valley, Nevada, has caused concern over the potential effects on shallow aquifer water levels. In 1992, water levels in Lahontan Valley were measured to construct a water-table map of the shallow aquifer prior to the effects of...
Manual hierarchical clustering of regional geochemical data using a Bayesian finite mixture model
Karl J. Ellefsen, David Smith
2016, Applied Geochemistry (75) 200-210
Interpretation of regional scale, multivariate geochemical data is aided by a statistical technique called “clustering.” We investigate a particular clustering procedure by applying it to geochemical data collected in the State of Colorado, United States of America. The clustering procedure partitions the field samples for the entire survey area into...
Geologic and geophysical models for Osage County, Oklahoma, with implications for groundwater resources
Mark R. Hudson, David V. Smith, Michael P. Pantea, Carol Becker
2016, Scientific Investigations Report 2016-5067
This report summarizes a three-dimensional (3-D) geologic model that was constructed to provide a framework to investigate groundwater resources of the Osage Nation in northeastern Oklahoma. This report also presents an analysis of an airborne electromagnetic (AEM) survey that assessed the spatial variation of electrical resistivity to depths as great...
User’s guide for GcClust—An R package for clustering of regional geochemical data
Karl J. Ellefsen, David B. Smith
2016, Techniques and Methods 7-C13
GcClust is a software package developed by the U.S. Geological Survey for statistical clustering of regional geochemical data, and similar data such as regional mineralogical data. Functions within the software package are written in the R statistical programming language. These functions, their documentation, and a copy of the user’s guide...
Groundwater exchanges near a channelized versus unmodified stream mouth discharging to a subalpine lake
James Constantz, Ramon C. Naranjo, Richard G. Niswonger, Kip K. Allander, B. Neilson, Donald O. Rosenberry, David W. Smith, C. Rosecrans, David A. Stonestrom
2016, Water Resources Research (52) 2157-2177
The terminus of a stream flowing into a larger river, pond, lake, or reservoir is referred to as the stream-mouth reach or simply the stream mouth. The terminus is often characterized by rapidly changing thermal and hydraulic conditions that result in abrupt shifts in surface water/groundwater (sw/gw) exchange patterns, creating the potential for...
Surface-air mercury fluxes across Western North America: A synthesis of spatial trends and controlling variables
Chris S. Eckley, Michael T. Tate, Che-Jen Lin, Mae S. Gustin, Stephen Dent, Collin A. Eagles-Smith, Michelle A. Lutz, Kimberly Wickland, Bronwen Wang, John E. Gray, Grant Edwards, David P. Krabbenhoft, David B. Smith
2016, Science of the Total Environment (568) 651-665
Mercury (Hg) emission and deposition can occur to and from soils, and are an important component of the global atmospheric Hg budget. This paper focuses on synthesizing existing surface-air Hg flux data collected throughout the Western North American region and is part of a series of geographically focused Hg synthesis...