Deposition of mercury in forests across a montane elevation gradient: Elevational and seasonal patterns in methylmercury inputs and production
Jacqueline R. Gerson, Charles T. Driscoll, Jason D. Demers, Amy K. Sauer, Bradley D. Blackwell, Mario R. Montesdeoca, James B. Shanley, Donald S. Ross
2017, Journal of Geophysical Research G: Biogeosciences (122) 1922-1939
Global mercury contamination largely results from direct primary atmospheric and secondary legacy emissions, which can be deposited to ecosystems, converted to methylmercury, and bioaccumulated along food chains. We examined organic horizon soil samples collected across an elevational gradient on Whiteface Mountain in the Adirondack region of New York State, USA...
A validation of 11 body-condition indices in a giant snake species that exhibits positive allometry
Bryan Falk, Ray W. Snow, Robert N. Reed
2017, PLoS ONE (12) 1-20
Body condition is a gauge of the energy stores of an animal, and though it has important implications for fitness, survival, competition, and disease, it is difficult to measure directly. Instead, body condition is frequently estimated as a body condition index (BCI) using length and mass measurements. A desirable BCI...
An assessment of food habits, prey availability, and nesting success of golden eagles within the Desert Renewable Energy Conservation Plan Area
Kathleen M. Longshore, Todd Esque, Kenneth Nussear, Diego R. Johnson, Matthew Simes, Richard D. Inman
2017, Report
Within the Desert Renewable Energy Conservation Plan area, which encompasses California’s Mojave Desert, development and operation of renewable energy facilities has the potential to impact golden eagle (Aquila chrysaetos) populations through loss of habitat and prey base. Developing an effective conservation strategy that aims to mitigate for such operations is necessary to...
Methodology for time-domain estimation of storm time geoelectric fields using the 3-D magnetotelluric response tensors
Anna Kelbert, Christopher Balch, Antti Pulkkinen, Gary D. Egbert, Jeffrey J. Love, E. Joshua Rigler, Ikuko Fujii
2017, Space Weather (15) 874-894
Geoelectric fields at the Earth's surface caused by magnetic storms constitute a hazard to the operation of electric power grids and related infrastructure. The ability to estimate these geoelectric fields in close to real time and provide local predictions would better equip the industry to mitigate negative impacts on their...
Geochemical characterization of groundwater discharging from springs north of the Grand Canyon, Arizona, 2009–2016
Kimberly R. Beisner, Fred D. Tillman, Jessica R. Anderson, Ronald C. Antweiler, Donald J. Bills
2017, Scientific Investigations Report 2017-5068
A geochemical study was conducted on 37 springs discharging from the Toroweap Formation, Coconino Sandstone, Hermit Formation, Supai Group, and Redwall Limestone north of the Grand Canyon near areas of breccia-pipe uranium mining. Baseline concentrations were established for the elements As, B, Li, Se, SiO2, Sr, Tl, U, and V....
Climate change and tree-line ecosystems in the Sierra Nevada: Habitat suitability modelling to inform high-elevation forest dynamics monitoring
Peggy E. Moore, Otto Alvarez, Shawn T. McKinney, Wenkai Li, Matthew L. Brooks, Qinghua Guo
2017, Natural Resource Report NPS/SIEN/NRR—2017/1476
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...
Spatial and temporal variability in benthic invertebrate assemblages in Upper Klamath Lake, Oregon
Natalie J. Stauffer-Olsen, James L. Carter, Steven V. Fend
2017, Northwest Science (91) 257-271
Upper Klamath Lake (UKL) in southern Oregon has experienced declines in water quality due to excessive nutrient loading. This has led to annual cyanobacterial blooms, primarily of Aphanizomenon flos-aquae (AFA). Benthic invertebrates are important food resources for benthic feeding fishes; however, they can increase autochthonous nutrient cycling in lakes and as a...
Mapping tree density in forests of the southwestern USA using Landsat 8 data
Kamal Humagain, Carlos Portillo-Quintero, Robert D. Cox, James W. Cain III
2017, Forests (8) 1-15
The increase of tree density in forests of the American Southwest promotes extreme fire events, understory biodiversity losses, and degraded habitat conditions for many wildlife species. To ameliorate these changes, managers and scientists have begun planning treatments aimed at reducing fuels and increasing understory biodiversity. However, spatial variability in tree...
Suitability of oyster restoration sites along the Louisiana coast: Examining site and stock × site interaction
Lindsay Schwarting Miller, Jerome F. La Peyre, Megan K. LaPeyre
2017, Journal of Shellfish Research (36) 341-351
Recognition of the global loss of subtidal oyster reefs has led to a rise in reef restoration efforts, including in the Gulf of Mexico. Created reef success depends entirely on selecting a location that supports long-term oyster growth and survival, including the recruitment and survival of on-reef oysters. Significant changes...
Rapid response for invasive waterweeds at the arctic invasion front: Assessment of collateral impacts from herbicide treatments
Suresh Sethi, Michael P. Carey, John M. Morton, Edgar Guerron-Orejuela, Robert Decino, Mark Willette, James Boersma, Jillian Jablonski, Cheryl Anderson
2017, Biological Conservation (212) 300-309
The remoteness of subarctic and arctic ecosystems no longer protects against invasive species introductions. Rather, the mix of urban hubs surrounded by undeveloped expanses creates a ratchet process whereby anthropogenic activity is sufficient to introduce and spread invaders, but for which the costs of monitoring and managing remote ecosystems is...
Incorporating Allee effects into the potential biological removal level
Humza Hadier, Sarah Oldfield, Tiffany Tu, Rosa Moreno, Jay E. Diffendorfer, Eric A. Eager, Richard A. Erickson
2017, Natural Resource Modeling (30) 1-16
Potential biological removal (PBR) is an approach used to calculate sustainable harvest and “take” limits for populations. PBR was originally derived assuming logistic growth while ignoring the effects of small population size (i.e., an Allee effect). We derived a version of PBR that includes an Allee effect (i.e., small population...
Celebrating ten years of collaboration
W. Matthew Cushing
2017, GEOSUR Newsletter (4) 4-5
Since the GEOSUR Program launched in 2007, the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center has had the honor of collaborating with CAF, PAIGH, and others supporting the Latin America GEOSUR Program. The catalyst for starting the program was the convergence of regional geospatial activities USGS,...
Intra‐annual variability of Silver Carp populations in the Des Moines River, USA
Christopher J. Sullivan, Carlos A. Camacho, Michael J. Weber, Clay Pierce
2017, North American Journal of Fisheries Management (37) 836-849
Since their introduction in the 1970s, Silver Carp Hypophthalmichthys molitrix have spread throughout the Mississippi River basin. Management of any species relies on an accurate understanding of population characteristics and dynamics. However, Silver Carp seasonal sampling variation is unknown. Sampling during periods of peak catch rates would facilitate Silver Carp assessment and...
Uncertainty, variability, and earthquake physics in ground‐motion prediction equations
Annemarie S. Baltay, Thomas C. Hanks, Norm A. Abrahamson
2017, Bulletin of the Seismological Society of America (107) 1754-1772
Residuals between ground‐motion data and ground‐motion prediction equations (GMPEs) can be decomposed into terms representing earthquake source, path, and site effects. These terms can be cast in terms of repeatable (epistemic) residuals and the random (aleatory) components. Identifying the repeatable residuals leads to a GMPE with reduced uncertainty for a...
Porosity and pore size distribution in a sedimentary rock: Implications for the distribution of chlorinated solvents
Allen M. Shapiro, Chrsitopher E. Evans, Erin C. Hayes
2017, Journal of Contaminant Hydrology (203) 70-84
Characterizing properties of the rock matrix that control retention and release of chlorinated solvents is essential in evaluating the extent of contamination and the application of remediation technologies in fractured rock. Core samples from seven closely spaced boreholes in a mudstone subject to trichloroethene (TCE) contamination were analyzed using Mercury...
How well do route survey areas represent landscapes at larger spatial extents? An analysis of land cover composition along Breeding Bird Survey routes
Joseph A. Veech, Keith L. Pardieck, David Ziolkowski
2017, Condor (119) 607-615
The occurrence of birds in a survey unit is partly determined by the habitat present. Moreover, some bird species preferentially avoid some land cover types and are attracted to others. As such, land cover composition within the 400 m survey areas along a Breeding Bird Survey (BBS) route clearly influences...
Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?
Darryl W. Hondorp, David Bennion, Edward F. Roseman, Christopher M. Holbrook, James C. Boase, Justin A. Chiotti, Michael V. Thomas, Todd C. Wills, Richard Drouin, Steven T. Kessel, Charles C. Krueger
2017, PLoS ONE (12)
Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens) into commercial navigation channels,...
Spatial heterogeneity of within-stream methane concentrations
John T. Crawford, Luke C. Loken, William E. West, Benjamin Crary, Seth A. Spawn, Nicholas Gubbins, Stuart E. Jones, Robert G. Striegl, Emily H. Stanley
2017, Journal of Geophysical Research G: Biogeosciences (122) 1036-1048
Streams, rivers, and other freshwater features may be significant sources of CH4 to the atmosphere. However, high spatial and temporal variabilities hinder our ability to understand the underlying processes of CH4 production and delivery to streams and also challenge the use of scaling approaches across large areas. We studied a stream having...
Field-trip guide to a volcanic transect of the Pacific Northwest
Dennis Geist, John A. Wolff, Karen Harpp
2017, Scientific Investigations Report 2017-5022-M
The Pacific Northwest region of the United States provides world-class and historically important examples of a wide variety of volcanic features. This guide is designed to give a broad overview of the region’s diverse volcanism rather than focusing on the results of detailed studies; the reader should consult the...
Temporal changes in nitrogen and phosphorus concentrations with comparisons to conservation practices and agricultural activities in the Lower Grand River, Missouri and Iowa, and selected watersheds, 1969–2015
Heather M. Krempa, Allison K. Flickinger
2017, Scientific Investigations Report 2017-5067
This report presents the results of a cooperative study by the U.S. Geological Survey and Missouri Department of Natural Resources to estimate total nitrogen (TN) and total phosphorus (TP) concentrations at monitoring sites within and near the Lower Grand River hydrological unit. The primary objectives of the study were to...
Effects of deep basins on structural collapse during large subduction earthquakes
Nasser A. Marafi, Marc O. Eberhard, Jeffrey W. Berman, Erin A. Wirth, Arthur D. Frankel
2017, Earthquake Spectra (33) 963-997
Deep sedimentary basins are known to increase the intensity of ground motions, but this effect is implicitly considered in seismic hazard maps used in U.S. building codes. The basin amplification of ground motions from subduction earthquakes is particularly important in the Pacific Northwest, where the hazard at long periods is...
Winter habitat associations of eastern spotted skunks in Virginia
Emily D. Thorne, Charles Waggy, David S. Jachowski, Marcella J. Kelly, W. Mark Ford
2017, Journal of Wildlife Management (81) 1042-1050
Eastern spotted skunk (Spilogale putorius) populations have declined throughout much of their range in the eastern United States over recent decades. Declines have been attributed to habitat loss or change, increased competition with sympatric mesocarnivore species, or disease. To better understand the extant distribution of spotted skunks in the Appalachian...
Variation and plasticity and their interaction with urbanization in Guadalupe Bass populations on and off the Edwards Plateau
Jessica E. Pease, Timothy B. Grabowski, Allison A. Pease
2017, Report
The Colorado River Basin in Texas has experienced major alterations to its hydrologic regime due to changing land and water use patterns. These anthropogenic influences on hydrologic variability have had major implications for riparian and aquatic ecosystems and the species dependent upon them. However, impacts are often assessed at a...
Paltry past-precipitation: Predisposing prairie dogs to plague?
David Eads, Dean E. Biggins
2017, Journal of Wildlife Management (81) 990-998
The plague bacterium Yersinia pestis was introduced to California in 1900 and spread rapidly as a sylvatic disease of mammalian hosts and flea vectors, invading the Great Plains in the United States by the 1930s to 1940s. In grassland ecosystems, plague causes periodic, devastating epizootics in colonies of black-tailed prairie dogs (Cynomys...
Relative sampling efficiency and movements of subadult Lake Sturgeon in the Lower Wolf River, Wisconsin
Zachary R. Snobl, Daniel A. Isermann, Ryan P. Koenigs, Joshua K. Raabe
2017, Transactions of the American Fisheries Society (146) 1070-1080
Understanding sampling efficiency and movements of subadult Lake Sturgeon Acipenser fulvescens is necessary to facilitate population rehabilitation and recruitment monitoring in large systems with extensive riverine and lacustrine habitats. We used a variety of sampling methods to capture subadult Lake Sturgeon (i.e., fish between 75 and 130 cm TL that had not...
