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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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Mountain goat declines in a protected, interior, native population Mountain goat declines in a protected, interior, native population

A shifting climate poses threats to alpine-adapted species including mountain goats. We used long-term (12 years) citizen science monitoring data and Bayesian N-mixture modeling to estimate population trends and drivers of population metrics among mountain goats in Glacier National Park (GNP). Median goats per site (n = 37 sites) declined by 45% (95% credible interval [CRI] = 32%, 57%)...
Authors
Tabitha A. Graves, William Michael Janousek, Michael Yarnall, Jami Belt

Miocene evolution of the Humboldt Current Miocene evolution of the Humboldt Current

Diatom records from the East Pisco Basin (EPB) of southern Peru and offshore Ocean Drilling Program (ODP) Hole 682 A reveal stepwise increases in the primary productivity of the Humboldt Current during the middle and late Miocene. Although diatoms are present back through the late middle Eocene, successively enhanced diatom production occurs during the Miocene in four steps. The first...
Authors
John A. Barron, Thomas J. DeVries, Jason J. Coenen

Best practice guidelines for targeted environmental DNA-based proficiency testing in non-regulatory contexts Best practice guidelines for targeted environmental DNA-based proficiency testing in non-regulatory contexts

The effective use of environmental DNA (eDNA) tools is contingent on strict adherence to established and validated methods. Differences in eDNA methods and quality assurance protocols may contribute to variability in results. However, quality assurance measures such as proficiency testing can provide independent evaluation of laboratory performance against pre-established test criteria...
Authors
Margaret Hunter, Adam Sepulveda, Dianne M. Gleeson, Alejandro Trujillo-Gonzalez, Caren C. Helbing, Helen C. Rees, Devin Nicole Jones-Slobodian, Rachel C. Miliano, Toshifumi Minamoto, Susanna Theroux, Cecilia Villacorta Rath, Taylor Wilcox, Hiroki Yamanaka, Katy E. Klymus

Remote compositional analyses of space-weathered lunar maria Remote compositional analyses of space-weathered lunar maria

Visible-to-shortwave infrared (VSWIR) reflectance spectroscopy has revolutionized our understanding of planetary surface compositions. However, space-weathering processes on airless bodies complicate quantitative compositional analyses. Here, we present a framework to isolate the signatures of space weathering in VSWIR spectra of lunar maria by leveraging radiative transfer modeling...
Authors
Ji-In Jung, Matheiu G. Lapotre, Ralph E. Milliken, Sarah E. Minson

Compilation of a nationwide river image dataset for identifying river channels and river rapids via deep learning Compilation of a nationwide river image dataset for identifying river channels and river rapids via deep learning

Remote sensing enables large-scale, image-based assessments of river dynamics, offering new opportunities for hydrological monitoring. We present a publicly available dataset consisting of 281,024 satellite and aerial images of U.S. rivers, constructed using an Application Programming Interface (API) and the U.S. Geological Survey’s National Hydrography Dataset. The dataset includes...
Authors
Nicholas Brimhall, Kelvyn K. Bladen, Tom Kerby, Carl J. Legleiter, Cameron Swapp, Hannah Fluckiger, Julie E Bahr, Makenna Roberts, Kaden Hart, Christina L. Stegman, Brennan Bean, Kevin Moon

Estimating the power of a standardized monitoring program for sportfish in Georgia, USA Estimating the power of a standardized monitoring program for sportfish in Georgia, USA

Objective Biological monitoring is a major component of management decisions and operating budgets of many natural resource management agencies. Given the scientific and financial commitments to monitoring, it is critical to estimate the ability to detect trends through time (i.e., power). Methods The Georgia Department of Natural Resources has monitored reservoir sport fish populations...
Authors
Troy N. Simon, Kelly F. Robinson, Brian J. Irwin

Microtextural characteristics of adularia in banded quartz veins from the Midas low-sulfidation epithermal deposit, Nevada Microtextural characteristics of adularia in banded quartz veins from the Midas low-sulfidation epithermal deposit, Nevada

High-grade ores at the Miocene Midas low-sulfidation epithermal deposit in northern Nevada are confined to crustiform quartz veins containing abundant adularia. Micro-X-ray fluorescence elemental mapping reveals that adularia is a common gangue mineral occurring in colloform bands, bands showing bladed textures, and bands with dendritic terminations. The adularia aggregates have delicate...
Authors
Lauren R. Terry, Thomas Monecke, T. James Reynolds, Filip Kasprowicz, Katharina I. Pfaff

The biosphere in the Anthropocene The biosphere in the Anthropocene

Earth’s biosphere is in a period of rapid change, resulting from anthropogenic pressures such as climate change, habitat loss and species translocation and extinction. The extraordinary pace of change has led to the suggestion that we live in a new geological epoch of time called the Anthropocene. In this theme issue, we explore the major changes to the terrestrial and marine biospheres...
Authors
Mark Williams, Mary L. McGann, Moriaki Yasuhara, Chhaya Chaudhary, Lisa Barber, Kerry Allen

An energetic tradeoff best explains parturition timing in grizzly bears An energetic tradeoff best explains parturition timing in grizzly bears

Timing of grizzly bear (Ursus arctos) parturition during hibernation has been explained by ancestral traits (delayed implantation, altricial young, obligate maternal denning), but the ultimate driver underlying precise timing has not been fully explored. Capitalizing on an observed latitudinal increase in denning duration among four populations in interior North America, we tested two...
Authors
C. M. Costello, L. L. Roberts, D. D. Bjornlie, M. D. Cameron, J. G. Clapp, Mark Haroldson, G. V. Hilderbrand, K. Joly, W. Kasworm, J. M. Nicholson, T. Radandt, M. S. Sorum, J. E. Teisberg, Frank T. van Manen, M. A. Vinks

Revisiting the geochronology of late Quaternary marine terraces and uplift rates in coastal Santa Barbara County, California, USA Revisiting the geochronology of late Quaternary marine terraces and uplift rates in coastal Santa Barbara County, California, USA

In several early studies, central California marine terraces between Santa Barbara and Point Conception were interpreted to record sea-level high stands of the last interglacial complex, ∼80 ka to ∼120 ka (marine isotope stage [MIS] 5). These ages and their elevations (∼20 m to ∼45 m) indicate modest rates of tectonic uplift, similar to those from other localities in southern and central
Authors
Daniel R. Muhs, R. Randall Schumann, Jordon Bright, Helen M. Roberts, Lindsey T. Groves

Widespread terrestrial ecosystem disruption at the onset of the Paleocene–Eocene Thermal Maximum Widespread terrestrial ecosystem disruption at the onset of the Paleocene–Eocene Thermal Maximum

The Paleocene–Eocene Thermal Maximum (PETM, ~56 Mya) interval was marked by massive 13C-depleted carbon emissions into the ocean/atmosphere system, manifested as a negative carbon isotope excursion (CIE) in sedimentary components, and ~5 °C global average warming. Episodes of hydrological perturbations and soil-erosion have been widely documented for the PETM but their link with...
Authors
Mei Nelissen, Debra A. Willard, Han Konijnenburg-van Cittert, Gabriel J. Bowen, Teuntje Hollaar, Appy Sluijs, Joost Frieling, Henk Brinkhuis

Toxicity of anticoagulant rodenticides on Pacific salmon: Assessing lethal and sublethal effects Toxicity of anticoagulant rodenticides on Pacific salmon: Assessing lethal and sublethal effects

To restore native biodiversity on island ecosystems containing invasive rodents, partial- and whole-island eradications generally rely on broadcast baiting with anticoagulant rodenticides (ARs). This approach can result in bait pellets entering aquatic environments, raising concerns about effects to non-target fish. Salmonids are a dominant group of fishes on many temperate islands...
Authors
Lillian M. Pavord, Melissa K. Driessnack, Aaron B. Shiels, Steven Volker, Barnett A. Rattner, Jenifer McIntyre
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