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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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High-precision 40Ar/39Ar dating of Quaternary basalts from Auckland Volcanic Field, New Zealand, with implications for eruption rates and paleomagnetic correlations High-precision 40Ar/39Ar dating of Quaternary basalts from Auckland Volcanic Field, New Zealand, with implications for eruption rates and paleomagnetic correlations

The Auckland Volcanic Field (AVF), which last erupted ca. 550 years ago, is a late Quaternary monogenetic basaltic volcanic field (ca. 500 km2) in the northern North Island of New Zealand. Prior to this study only 12 out of the 53 identified eruptive centres of the AVF had been reliably dated. Careful sample preparation and 40Ar/39Ar analysis has increased the number of well-dated...
Authors
Graham S. Leonard, Andrew T. Calvert, Jenni L Hopkins, Colin J.N. Wilson, Elaine R. Smid, Jan Lindsay, Duane E. Champion

Host vs. pathogen evolutionary arms race: Effects of exposure history on individual response to a genetically diverse pathogen Host vs. pathogen evolutionary arms race: Effects of exposure history on individual response to a genetically diverse pathogen

Introduction: Throughout their range, bighorn sheep (Ovis canadensis) populations have seen significant disease-associated declines. Unfortunately, understanding of the underlying epidemiological processes driving the disease dynamics in this species has hindered conservation efforts aimed at improving the health and long-term viability of these populations. Individual response to...
Authors
Daniel P. Walsh, Brandi L. Felts, E. Frances Cassirer, Thomas E. Besser, Jonathan A. Jenks

Identifying mismatches between conservation area networks and vulnerable populations using spatial randomization Identifying mismatches between conservation area networks and vulnerable populations using spatial randomization

Grassland birds are among the most globally threatened bird groups due to substantial degradation of native grassland habitats. However, the current network of grassland conservation areas may not be adequate for halting population declines and biodiversity loss. Here, we evaluate a network of grassland conservation areas within Wisconsin, U.S.A., that includes both large Focal...
Authors
Laura A. Nunes, Christine Ribic, Benjamin Zuckerberg

Mid-Atlantic big brown and eastern red bats: Relationships between acoustic activity and reproductive phenology Mid-Atlantic big brown and eastern red bats: Relationships between acoustic activity and reproductive phenology

Acoustic data are often used to describe bat activity, including habitat use within the summer reproductive period. These data inform management activities that potentially impact bats, currently a taxa of high conservation concern. To understand the relationship between acoustic and reproductive timing, we sampled big brown bats (Eptesicus fuscus) and eastern red bats (Lasiurus borealis...
Authors
Sabrina Deeley, W. Mark Ford, Nicholas Kalen, Samuel R. Freeze, Micheal St. Germain, Michael Muthersbaugh, Elaine Barr, Andrew Kniowski, Alexander Silvis, Jesse De La Cruz

Population estimates and land cover use of wintering Mountain Plovers in Texas Population estimates and land cover use of wintering Mountain Plovers in Texas

Conservation of migratory birds throughout the full annual cycle requires a comprehensive understanding of abundance and distribution in interconnected breeding, migration, and wintering habitats. The Mountain Plover (Anarhynchus montanus) is a rare endemic breeder of the Rocky Mountain and Great Plains regions that migrates to wintering grounds in the southwestern USA and northern...
Authors
James E. Lyons, Brad A. Andres, Kelli L. Stone, Allison K. Pierce, Kammie L. Kruse

Reconnaissance basement geology and tectonics of North Zealandia Reconnaissance basement geology and tectonics of North Zealandia

New rock dredge samples supply key information to establish the tectonic and geological framework of the northern two-thirds of the 95% submerged Zealandia continent. The R/V Investigator voyage IN2016T01 to the Fairway Ridge, Coral Sea, obtained poorly sorted poly-lithologic pebbly to cobbly sandstones, well sorted fine grained sandstones, mudstones, bioclastic limestones, and basaltic...
Authors
Nick Mortimer, Simon Williams, Maria Seton, Andrew T. Calvert, Tod Waight, Rose E. Turnbull, Demian Nelson, Mike Palin, Jahandar Ramezani, Matthew W. Sagar, Andy Tulloch, Wanda Stratford, Julien Collot, Samuel Etienne

Reevaluation of thermal maturity and stages of petroleum formation of the Mississippian Barnett Shale, Fort Worth Basin, Texas Reevaluation of thermal maturity and stages of petroleum formation of the Mississippian Barnett Shale, Fort Worth Basin, Texas

New data including measured reflectance (%Ro), programmed open-system pyrolysis data, and kerogen elemental analyses obtained on the Mississippian Barnett Shale in the Fort Worth Basin, Texas, indicate that secondary-gas generation starts at 1.5% Ro and not at the previously prescribed 1.1% Ro. Oil-cracking kinetic parameters derived from pyrolysis experiments in the presence and absence...
Authors
Michael Lewan, M.J. Pawlewicz

Remote sensing-based actual evapotranspiration assessment in a data-scarce area of Brazil: A case study of the Urucuia Aquifer System Remote sensing-based actual evapotranspiration assessment in a data-scarce area of Brazil: A case study of the Urucuia Aquifer System

The large groundwater reserves of the Urucuia Aquifer System (UAS) enabled agricultural development and economic growth in the western Bahia State, in northeastern Brazil. Over the last several years, concern has grown around the aquifer’s diminishing water levels, and water balance (WB) studies are in demand. Considering the lack of measured actual evapotranspiration (ETa), a major...
Authors
Bruno César Comini de Andrade, Eber José de Andrade Pinto, Anderson Ruhoff, Gabriel B. Senay

Seasonal spatial ecology of Lake Trout in Lake Erie Seasonal spatial ecology of Lake Trout in Lake Erie

Objective Lake Trout Salvelinus namaycush are native coldwater apex predators that play an important role in maintaining ecosystem functionality and diversity in the Laurentian Great Lakes. Following population collapses, rehabilitation efforts were widely initiated in the Great Lakes to reestablish self‐sustaining Lake Trout populations. Lake Erie may pose a challenge to these...
Authors
Tyler Funnell, Travis Brenden, Richard Kraus, Tom MacDougall, James Markham, Charles Richard Murray, Jason Robinson, Christopher S. Vandergoot

Strontium isotopes reveal diverse life history variations, migration patterns, and habitat use for Broad Whitefish (Coregonus nasus) in Arctic, Alaska Strontium isotopes reveal diverse life history variations, migration patterns, and habitat use for Broad Whitefish (Coregonus nasus) in Arctic, Alaska

Conservation of Arctic fish species is challenging partly due to our limited ability to track fish through time and space, which constrains our understanding of life history diversity and lifelong habitat use. Broad Whitefish (Coregonus nasus) is an important subsistence species for Alaska’s Arctic Indigenous communities, yet little is known about life history diversity, migration...
Authors
Jason C. Leppi, Daniel J. Rinella, Mark S. Wipfli, Randy J. Brown, Karen J. Spaleta, Matthew S. Whitman

Supporting the adaptive capacity of species through more effective knowledge exchange with conservation practitioners Supporting the adaptive capacity of species through more effective knowledge exchange with conservation practitioners

There is an imperative for conservation practitioners to facilitate the ability of biodiversity to adapt to accelerating environmental change. Evolutionary biologists are well-positioned to inform the development of evidence-based management strategies that will effectively support the adaptive capacity of species and ecosystems. Conservation practitioners increasingly accept that...
Authors
Carly N. Cook, Erik A. Beever, Lindsey Thurman, Laura Thompson, John E. Gross, Andrew R. Whiteley, Adrienne Nicotra, Jennifer A. Szymanski, Carlos Botero, Kimberley Hall, Ary A. Hoffmann, Gregor W. Schuurman, Carla Sgro

The diets of wild and reintroduced whooping cranes The diets of wild and reintroduced whooping cranes

Abstract: We characterized the diets of the recently established Eastern Migratory Population (EMP) and the extant Aransas Wood Buffalo population (AWBP). Starting in 2013, frozen proventriculus and ventriculus contents from previously collected dead whooping cranes from both populations were examined to identify dietary items and quantity. EMP whooping cranes (n = 29) consumed benthic...
Authors
Heather A. Neri, Glenn H. Olsen, Eric C. Kindahl, Susan L. Carney
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