Estimating abundance and simulating fertility control in feral burros
Jay V. Gedir, James W. Cain III, Bruce C. Lubow, Talesha Karish, David K. Delaney, Gary W. Roemer
2021, Journal of Wildlife Management (85) 1187-1199
Overabundant populations of feral equids are negatively impacting rangelands in the western United States. To effectively manage these populations, robust estimates of abundance and demography are necessary, as well as cost-effective methods of reducing abundance. We used a double-observer-sightability aerial survey method to estimate the number of feral burros (Equus...
Sediment transport, turbidity, and dissolved oxygen responses to annual streambed drawdowns for downstream fish passage in a flood control reservoir
Liam N. Schenk, Heather M. Bragg
2021, Journal of Environmental Management (295)
Sediment transport, turbidity, and dissolved oxygen were evaluated during six consecutive water years (2013–2018) of drawdowns of a flood control reservoir in the upper Willamette Valley, Oregon, USA. The drawdowns were conducted to allow volitional passage of endangered juvenile chinook salmon through the dam's regulating outlets by lowering the reservoir elevation...
New geochemical tools for investigating resource and energy functions at deep-sea cold seeps using amino-acid δ15N in chemosymbiotic mussels (Bathymodiolus childressi)
Natasha Vokhshoori, Matt McCarthy, Hilary G. Close, Amanda Demopoulos, Nancy G. Prouty
2021, Geobiology (19) 601-617
In order to reconstruct the ecosystem structure of chemosynthetic environments in the fossil record, geochemical proxies must be developed. Here, we present a suite of novel compound-specific isotope parameters for tracing chemosynthetic production with a focus on understanding nitrogen dynamics in deep-sea cold seep environments. We examined the chemosymbiotic bivalve Bathymodiolus...
The marine terraces of Santa Cruz Island, California: Implications for glacial isostatic adjustment models of last-interglacial sea-level history
Daniel R. Muhs, R. Randall Schumann, Lindsey T. Groves, Kathleen R. Simmons, Christopher R. Florian
2021, Geomorphology (389)
Glacial isostatic adjustment (GIA) models hypothesize that along coastal California, last interglacial (LIG, broadly from ~130 to ~115 ka) sea level could have been as high as +11 m to +13 m, relative to present, substantially higher than the commonly estimated elevation of +6 m....
Physiomorphic transformation in extreme endurance migrants: Revisiting the case of bar-tailed godwits preparing for trans-pacific flights
Theunis Piersma, Robert E. Gill Jr., Daniel R. Ruthrauff
2021, Frontiers in Ecology and Evolution (9)
In a 1998 paper entitled “Guts don’t fly: small digestive organs in obese bar-tailed godwits,” Piersma and Gill (1998) showed that the digestive organs were tiny and the fat loads huge in individuals suspected of embarking on a non-stop flight from Alaska to New Zealand. It was suggested that prior...
Assessment of a conservative mixing model for the evaluation of constituent behavior below river confluences, Elqui River Basin, Chile
Catalina Rossi, Jorge Oyarzun, Pablo Pasten, Robert L. Runkel, Jorge Núñez, Denisse Duhalde, Hugo Maturana, Eduardo Rojas, José L. Arumí, Daniela Castillo, Ricardo Oyarzun
2021, River Research and Applications (37) 967-978
Fate and transport modeling of water-borne contaminants is a data demanding and costly endeavor, requiring considerable expes such, it becomes important to know when a complex modeling approach is required, and when a simpler approach is adequate. This is the main objective herein, where a conservative mixing model is used...
Extensibility of U-net neural network model for hydrographic feature extraction and implications for hydrologic modeling
Larry V. Stanislawski, Ethan J. Shavers, Shaowen Wang, Zhe Jiang, E. Lynn Usery, Evan Moak, Alexander Duffy, Joel Schott
2021, Remote Sensing (13)
Accurate maps of regional surface water features are integral for advancing ecologic, atmospheric and land development studies. The only comprehensive surface water feature map of Alaska is the National Hydrography Dataset (NHD). NHD features are often digitized representations of historic topographic map blue lines and may be outdated. Here we...
Assessing habitat change and migration of barrier islands
Nicholas Enwright, Lei Wang, P. Soupy Dalyander, Hongqing Wang, Michael Osland, Rangley C. Mickey, Robert L. Jenkins III, Elizabeth Godsey
2021, Estuaries and Coasts (44) 2073-2086
Barrier islands are dynamic environments that experience gradual change from waves, tides, and currents, and rapid change from extreme storms. These islands are expected to change drastically over the coming century due to accelerated sea-level rise and changes in frequency and intensity of storm events. The dynamic nature of barrier...
Detecting subtle change from dense landsat time series: Case studies of mountain pine beetle and spruce beetle disturbance
Su Ye, John Rogan, Zhe Zhu, Todd Hawbaker, Sarah J. Hart, Robert A. Andrus, Arjan J.H. Meddens, Jeffery A. Hicke, J. Ronald Eastman, Dominik Kulakowski
2021, Remote Sensing of Environment (263)
In contrast to abrupt changes caused by land cover conversion, subtle changes driven by a shift in the condition, structure, or other biological attributes of land often lead to minimal and slower alterations of the terrestrial surface. Accurate mapping and monitoring of subtle change are crucial for an early warning...
Permeable groundwater pathways and tritium migration patterns from the HANDLEY underground nuclear test, Pahute Mesa, Nevada
Tracie R. Jackson
2021, Scientific Investigations Report 2021-5032
The HANDLEY nuclear test was detonated at about 2,700 feet below the water table on March 26, 1970, in Pahute Mesa, south-central Nevada. Measured tritium concentrations in boreholes ER-20-12 and PM-3 indicate that a shallow tritium plume has migrated more than 1 mile (mi) downgradient from the HANDLEY test...
Incorporating water quality analysis into navigation assessments as demonstrated in the Mississippi River Basin
Barbara Kleiss, Jennifer C. Murphy, Casey M. Mayne, Jake P. Allgeier, Amanda B. Edmondson, Katrina C. Ginsberg, Keaton E. Jones, Timothy J. Lauth, Emily L. Moe, Julie W. Murphy, Mead Allison
2021, Journal of Waterway, Port, Coastal, and Ocean Engineering (147)
A description of historical and ambient water quality conditions is often required as part of navigational studies. This paper describes a series of tools developed by the USGS that can aid navigation managers in developing water quality assessments. The tools use R, a statistical software program, and...
Evaluation of techniques for mitigating snowmelt infiltration-induced landsliding in a highway embankment
Eric Hinds, Ning Lu, Benjamin B. Mirus, Jonathan W. Godt, Alexandra Wayllace
2021, Engineering Geology (291)
Infiltration-induced landslides threaten transportation infrastructure around the world, and impose both direct costs through repair and remediation work and indirect costs through lost economic activity. Therefore, finding the most cost-effective techniques to mitigate slope failures that can impact critical infrastructure links is desirable. The Straight Creek landslide, which affects a...
When Wyoming became Superior: Oblique convergence along the southern Trans-Hudson orogen
Paul A. Bedrosian, Carol A. Finn
2021, Geophysical Research Letters (48)
The Trans-Hudson orogen (THO) is one of the best-preserved Proterozoic orogens on Earth, largely unaffected by subsequent tectonism, yet its southern extent lies concealed beneath the North American Central Plains. A new 3D resistivity model over the southern orogen is developed and interpreted alongside borehole, potential field,...
Surface-mining modeling for USGS coal assessments
Paul E. Pierce
2021, Open-File Report 2021-1059
The value of national coal deposits is determined for the Solid Fuel Energy Resources Assessment and Research Project through economic evaluations using hypothetical mining models. Deposits near the surface are evaluated with the U.S. Geological Survey (USGS) surface-mining model, which is patterned after the standard mining techniques and infrastructures of...
Decision analysis of barrier placement and targeted removal to control invasive carp in the Tennessee River Basin
Max Post van der Burg, David R. Smith, Aaron R. Cupp, Mark W. Rogers, Duane Chapman
2021, Open-File Report 2021-1068
Controlling range expansion of invasive carp (specifically Hypophthalmichthys spp.) on the Tennessee River is important to conserve the ecological and economic benefits provided by the river. We collaborated with State and Federal agencies (the stakeholder group) to develop a decision framework and decision support model to evaluate strategies to control...
Movement of sediment through a burned landscape: Sediment volume observations and model comparisons in the San Gabriel Mountains, California, USA
Francis K. Rengers, Luke A. McGuire, Jason W. Kean, Dennis M. Staley, Mariana Dobre, Peter R. Robichaud, Tyson Swetnam
2021, Journal of Geophysical Research (126)
Post-wildfire changes to hydrologic and geomorphic systems can lead to widespread sediment redistribution. Understanding how sediment moves through a watershed is crucial for assessing hazards, developing debris flow inundation models, engineering sediment retention solutions, and quantifying the role that disturbances play in landscape evolution. In this study,...
Is there an urban pesticide signature? Urban streams in five U.S. regions share common dissolved-phase pesticides but differ in predicted aquatic toxicity
Lisa H. Nowell, Patrick W. Moran, Laura M. Bexfield, Barbara Mahler, Peter C. Van Metre, Paul M. Bradley, Travis S. Schmidt, Daniel T. Button, Sharon L. Qi
2021, Science of the Total Environment (793)
Pesticides occur in urban streams globally, but the relation of occurrence to urbanization can be obscured by regional differences. In studies of five regions of the United States, we investigated the effect of region and urbanization on the occurrence and potential toxicity of dissolved...
Citizen science data collection for integrated wildlife population analyses
Catherine C. Sun, Jeremy E. Hurst, Angela K. Fuller
2021, Frontiers in Ecology and Evolution (9)
Citizen science, or community science, has emerged as a cost-efficient method to collect data for wildlife monitoring. To inform research and conservation, citizen science sampling designs should collect data that match the robust statistical analyses needed to quantify species and population patterns. Further increasing the contributions of citizen...
A new species of tree hyrax (Procaviidae: Dendrohyrax) from West Africa and the significance of the Niger–Volta interfluvium in mammalian biogeography
John F. Oates, Neal Woodman, Philippe Gaubert, Eric J. Sargis, Edward D. Wiafe, Emilie Lecompte, Francoise Dowsett-Lemaire, Robert J. Dowsett, Sery Gonedele Bi, Rachel A. Ikemeh, Chabi Djagoun, Louise Tomsett, Simon K. Bearder
2021, Zoological Journal of the Linnean Society
Tree hyraxes (Dendrohyrax) are one of only three genera currently recognized in Procaviidae, the only extant family in the mammalian order Hyracoidea. Their taxonomy and natural history have received little attention in recent decades. All tree hyrax populations of Guineo-Congolian forests of Africa are currently treated as a single species, Dendrohyrax...
Effects of tidally varying river flow on entrainment of juvenile salmon into Sutter and Steamboat Sloughs
Jason G. Romine, Russell Perry, Paul Stumpner, Aaron R. Blake, Jon R. Burau
2021, San Francisco Estuary and Watershed Science (19) 1-17
Survival of juvenile salmonids in the Sacramento–San Joaquin Delta (Delta) varies by migration route, and thus the proportion of fish that use each route affects overall survival through the Delta. Understanding factors that drive routing at channel junctions along the Sacramento River...
Hippopotamus movements structure the spatiotemporal dynamics of an active anthrax outbreak
Keenan Stears, Melissa H. Schmitt, Wendy Christine Turner, Douglas J. McCauley, Epaphras A. Muse, Halima Kiwango, Daniel Matheyo, Benezeth M. Mutayoba
2021, Ecosphere (12)
Globally, anthrax outbreaks pose a serious threat to people, livestock, and wildlife. Furthermore, environmental change can exacerbate these outbreak dynamics by altering the host–pathogen relationship. However, little is known about how the quantitative spatial dynamics of host movement and environmental change may affect the spread of Bacillus anthracis, the causative agent...
Spatial Gaussian processes improve multi-species occupancy models when range boundaries are uncertain and nonoverlapping
Wilson Wright, Kathryn M. Irvine, Tom Rodhouse, Andrea R. Litt
2021, Ecology and Evolution (11) 8516-8527
Species distribution models enable practitioners to analyze large datasets of encounter records and make predictions about species occurrence at unsurveyed locations. In omnibus surveys that record data on multiple species simultaneously, species ranges are often nonoverlapping and misaligned with the administrative unit defining the spatial domain of interest (e.g.,...
Use of the MODFLOW 6 water mover package to represent natural and managed hydrologic connections
Eric D. Morway, Christian D. Langevin, Joseph D. Hughes
2021, Groundwater (59) 913-924
The latest release of MODFLOW 6, the current core version of the MODFLOW groundwater modeling software, debuted a new package dubbed the “mover” (MVR). Using a generalized approach, MVR facilitates the transfer of water among any arbitrary combination of simulated features (i.e., pumping wells, stream, drains,...
Advancing estuarine ecological forecasts: Seasonal hypoxia in Chesapeake Bay
Donald Scavia, Isabella Bertani, Jeremy M. Testa, Aaron J. Bever, Joel D. Blomquist, Marjorie A. M. Friedrichs, Lewis C. Linker, Bruce Michael, Rebecca Murphy, Gary W. Shenk
2021, Ecological Applications (31)
Ecological forecasts are quantitative tools that can guide ecosystem management. The coemergence of extensive environmental monitoring and quantitative frameworks allows for widespread development and continued improvement of ecological forecasting systems. We use a relatively simple estuarine hypoxia model to demonstrate advances in addressing some of the...
Effects of climate and land-use change on thermal springs recharge—A system-based coupled surface-water and groundwater-flow model for Hot Springs National Park, Arkansas
Rheannon M. Hart, Scott J. Ikard, Phillip D. Hays, Brian R. Clark
2021, Scientific Investigations Report 2021-5045
A three-dimensional hydrogeologic framework of the Hot Springs anticlinorium beneath Hot Springs National Park, Arkansas, was constructed to represent the complex hydrogeology of the park and surrounding areas to depths exceeding 9,000 feet below ground surface. The framework, composed of 6 rock formations and 1 vertical fault emplaced beneath the...
