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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
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No evidence hunting bait increases American black bear population growth in Maine, USA No evidence hunting bait increases American black bear population growth in Maine, USA
American black bear (Ursus americanus) populations are increasing throughout much of North America. Use of multiple harvest methods, including hunting over bait, is intended to increase harvest success rates to meet harvest and population management objectives. However, black bear population growth can be influenced by food availability, and some speculate the use of bait may...
Authors
Dana J. Morin, Jennifer H. Vashon, Matthew O’Neal, Nathan J. Hostetter, Elizabeth A. Flaherty
Leveraging extensive soil, vegetation, fire, and land treatment data to inform restoration across the sagebrush biome Leveraging extensive soil, vegetation, fire, and land treatment data to inform restoration across the sagebrush biome
Context
Authors
Bryan C. Tarbox, Adrian P. Monroe, Michelle I. Jeffries, Justin L. Welty, Michael S. O’Donnell, Robert Arkle, David S. Pilliod, Peter S. Coates, Julie A. Heinrichs, Daniel Manier, Cameron L. Aldridge
What do we know without the catalog? Eliciting prior beliefs from experts for aftershock models What do we know without the catalog? Eliciting prior beliefs from experts for aftershock models
Fitting parametric seismological models to earthquake catalogs often comes with numerical challenges, especially when catalogs are small. An alternative way to quantify parameter values for a seismic region is by eliciting expert opinions on the seismological characteristics that each parameter corresponds to. For instance, expert beliefs on aftershock patterns can be formulated into...
Authors
Max Schneider, Peter Guttorp
Produced water geochemistry from hydraulically stimulated Niobrara Formation petroleum wells: Origin of salinity and temporal perspectives on treatment and reuse Produced water geochemistry from hydraulically stimulated Niobrara Formation petroleum wells: Origin of salinity and temporal perspectives on treatment and reuse
Produced water (i.e., a mixture of returned injection fluids and geologic formation brines) represents the largest volumetric waste stream associated with petroleum production in the United States. As such, produced water has been the focus of intense study with emphasis on understanding the geologic origin of the fluids, environmental impacts of unintended or intentional release...
Authors
Aaron M. Jubb, Jenna L. Shelton, Bonnie McDevitt, Kaela K. Amundson, Amanda Sha Herzberg, Jessica Chenault, Andrew Laurence Masterson, Matthew S. Varonka, Glenn D. Jolly, Christina A. DeVera, Elliott P. Barnhart, Michael J. Wilkins, Madalyn S. Blondes
New occurrences of the rare, REE minerals daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite from the Sheep Creek area, Montana, USA New occurrences of the rare, REE minerals daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite from the Sheep Creek area, Montana, USA
Over 30 small, discontinuous, tabular carbonatite bodies are located in the Sheep Creek area, Ravalli County, southwest Montana. The age and origin of these REE-Nb-rich deposits are currently being investigated. The purpose of this paper is to document the occurrence of several rare minerals, including daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite, in two of the...
Authors
Chris Gammons, Sarah Risedorf, Gary Wyss, Heather A. Lowers
Testing spatial out-of-sample area of influence for grain forecasting models Testing spatial out-of-sample area of influence for grain forecasting models
We examine the factors that determine if a grain forecasting model fit to one region can be transferred to another region. Prior research has proposed examining the area of applicability (AoA) of a model based on structurally similar characteristics in the Earth Observation predictors and weights based on the model derived feature importance. We expand on and evaluate this approach in...
Authors
Frank Davenport, Donghoon Lee, Shraddhanand Shukla, Greg Husak, W. Chris Funk, Michael Budde, James Rowland
Glucocorticoid and glycemic responses to immune challenge in a viviparous snake afflicted with an emerging mycosis Glucocorticoid and glycemic responses to immune challenge in a viviparous snake afflicted with an emerging mycosis
Disease may be both a cause and consequence of stress, and physiological responses to infectious disease may involve stress coping mechanisms that have important fitness consequences. For example, glucocorticoid and glycemic responses may affect host fitness by altering resource allocation and use in hosts, and these responses may be affected by competing stressors. To better understand...
Authors
Craig M. Lind, Joseph Agugliaro, Jason Ortega, Jenna N. Palmisano, Jeffrey M. Lorch, Tran Truong, Terence M. Farrell
Vortex trapping of suspended sand grains over ripples Vortex trapping of suspended sand grains over ripples
Coastal hydrodynamics and morphodynamics integrate the effects of small-scale fluid-sediment interactions; yet, these small-scale processes are not well understood. To investigate sediment trapping by turbulent coherent structures or vortices, the transport of coarse sand over ripples was analyzed in a small-oscillatory flow tunnel with phase-separated Particle Image and Tracking...
Authors
Donya P. Frank-Gilchrist, Allison M. Penko, Margaret L. Palmsten, Joseph Calantoni
Detection and transport of environmental DNA from two federally endangered mussels Detection and transport of environmental DNA from two federally endangered mussels
Environmental DNA (eDNA) offers a novel approach to supplement traditional surveys and provide increased spatial and temporal information on species detection, and it can be especially beneficial for detecting at risk or threatened species with minimal impact on the target species. The transport of eDNA in lotic environments is an important component in providing more informed...
Authors
Brandon James Sansom, Dannise Vannesa Ruiz-Ramos, Nathan Thompson, Maura O Roberts, Zachary Taylor, Katie Ortiz, Jess W. Jones, Catherine A. Richter, Katy E. Klymus
Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly Reproductive ecology and egg parasitism of the Samoan swallowtail butterfly
We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly (Papilio godeffroyi), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During monthly surveys of its only known host plant, Micromelum minutum, across eight sites in 2013 and 2014...
Authors
Paul C. Banko, Mark A. Schmaedick, Robert W. Peck, Adam C. Miles, Niela Leifi
Egg size scales negatively with system size in a periodic fish species Egg size scales negatively with system size in a periodic fish species
Optimal egg size theory implies that female organisms balance between fecundity and individual offspring investment according to their environment. Past interspecific studies suggest that fishes in large marine systems generally produce smaller eggs than those in small freshwater systems. We tested whether intraspecific egg size variation reflected a similar pattern by comparing egg size...
Authors
Scott T. Koenigbauer, Zachary S. Feiner, Benjamin Dickinson, Stephanie L. Shaw, Zoe Almeida, Mark Richard Dufour, Alexander James Gatch, Claire Schraidt, Tomas O. Hook
Seasonally varying contributions of contemporaneous and lagged sources of instream total nitrogen and phosphorus load across the Illinois River basin Seasonally varying contributions of contemporaneous and lagged sources of instream total nitrogen and phosphorus load across the Illinois River basin
Quantifying nutrient sources in streams, their temporal and spatial variability, and drivers of that variability can support effective water resources management. Yet a lack of data and modeling capabilities has previously prevented comprehensive quantification across both space and time. Here a dynamic SPARROW (Spatially Referenced Regressions on Watershed attributes) model that...
Authors
Noah M. Schmadel, Olivia L. Miller, Scott Ator, Matthew P. Miller, Gregory E. Schwarz, Dale M. Robertson, Andrew J. Sekellick, Kenneth D. Skinner, David A. Saad