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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
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