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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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Decoupling of species and plant communities of the U.S. Southwest: A CCSM4 climate scenario example Decoupling of species and plant communities of the U.S. Southwest: A CCSM4 climate scenario example
Climate change is predicted to alter the current climate suitability under which plant species and communities occur. Predictions of change have focused on individual species or entire communities, but theory indicates plants will not respond uniformly to climate change within or between communities. We developed models of the current climate suitability (the baseline) of 66 plant...
Authors
Kathryn A. Thomas, Brett A. Stauffer, Christopher J. Jarchow
A comparison of direct & indirect survey methods for estimating colonial nesting waterbird populations A comparison of direct & indirect survey methods for estimating colonial nesting waterbird populations
Population estimates derived from monitoring efforts can be sensitive to the survey method selected, potentially leading to biased estimates and low precision relative to true population size. While small unmanned aerial systems (UAS) present a unique opportunity to survey avian populations while limiting disturbance, relatively little is known about how this method compares with more...
Authors
Diann J. Prosser, Jeffery D. Sullivan, Christopher J. Gilbert, David F. Brinker, Peter C. McGowan, Carl R. Callahan, Ben Hutzell, Laurence E. Smith
Genetic diversity and IUCN Red List status Genetic diversity and IUCN Red List status
The International Union for Conservation of Nature (IUCN) Red List is an important and widely used tool for conservation assessment. The IUCN uses information about a species’ range, population size, habitat quality and fragmentation levels, and trends in abundance to assess extinction risk. Genetic diversity is not considered, although it affects extinction risk. Declining populations...
Authors
Chloe Schmidt, Sean M. Hoban, Margaret Hunter, Ivan Paz-Vinas, Colin J. Garroway
eDNA Metabarcoding Analyses of Diet in Yellow-Billed Loons of Northern Alaska eDNA Metabarcoding Analyses of Diet in Yellow-Billed Loons of Northern Alaska
Environmental DNA is a burgeoning tool used to address wide-ranging scientific questions, including determining diets of difficult-to-sample predators. Loons are large piscivorous diving birds that capture and consume prey underwater, making it nearly impossible to visually determine their diet via observation alone. Identifying species' diets is important for understanding basic life...
Authors
Damian M. Menning, Brian D. Uher-Koch, Melanie J. Flamme, Trey Simmons, Joel Schmutz, Sandra Talbot
Mapping ancient sedimentary organic matter molecular structure at nanoscales using optical photothermal infrared spectroscopy Mapping ancient sedimentary organic matter molecular structure at nanoscales using optical photothermal infrared spectroscopy
Elucidating the molecular structure of sedimentary organic matter (SOM) is key to understanding petroleum generation processes, as well as ancient sedimentary environments. SOM structure is primarily controlled by biogenic source material (e.g., marine vs. terrigenous), depositional conditions, and subsurface thermal history. Additional factors, e.g., strain, may also impact the...
Authors
Aaron M. Jubb, Martha Stokes, Ryan J. McAleer, Paul C. Hackley, Eoghan Dillion, Jing Qu
Peak Cenozoic warmth enabled deep-sea sand deposition Peak Cenozoic warmth enabled deep-sea sand deposition
The early Eocene (~ 56–48 million years ago) was marked by peak Cenozoic warmth and sea levels, high CO2, and largely ice-free conditions. This time has been described as a period of increased continental erosion and silicate weathering. However, these conclusions are based largely on geochemical investigation of marine mudstones and carbonates or study of intermontane Laramide basin...
Authors
Zachary FM Burton, Tim McHargue, Christopher H. Kremer, Richard B Bloch, Jared T. Gooley, Chayawan Jailka, Jake Harrington, Stephan A. Graham
Declines in body size of sockeye salmon associated with increased competition in the ocean Declines in body size of sockeye salmon associated with increased competition in the ocean
Declining body sizes have been documented for several species of Pacific salmon; however, whether size declines are caused mainly by ocean warming or other ecological factors, and whether they result primarily from trends in age at maturation or changing growth rates remain poorly understood. We quantified changes in mean body size and contributions from shifting size-at-age and age...
Authors
Jan Ohlberger, Timothy Joseph Cline, Daniel Schindler, Bert Lewis
The Volcanic Hazard Maps Database: An initiative of the IAVCEI Commission on Volcanic Hazards and Risk The Volcanic Hazard Maps Database: An initiative of the IAVCEI Commission on Volcanic Hazards and Risk
In this work we present the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) Commission on Volcanic Hazards and Risk (CVHR) Volcanic Hazard Maps Database and the accompanying volcanichazardmaps.org website. Using input from a series of IAVCEI CVHR Working Group on Hazard Mapping workshops, we developed a classification scheme and terminology...
Authors
Sarah E. Ogburn, Danielle Charlton, Diana Norgaard, Heather M. Wright, Eliza S. Calder, Jan Lindsay, John W. Ewert, Shinji Takarada, Yasuhisa Tajima
Applications of nonergodic site response models to ShakeAlert case studies in the Los Angeles area Applications of nonergodic site response models to ShakeAlert case studies in the Los Angeles area
In this study, we explore whether the Parker and Baltay (2022) site response models for the Los Angeles (LA) basin region can improve ground‐motion forecasts in the U.S. Geological Survey ShakeAlert earthquake early warning system (hereafter ShakeAlert). We implement the peak ground acceleration and peak ground velocity site response models of Parker and Baltay (2022) in ShakeAlert via...
Authors
Rongrong Lin, Grace Alexandra Parker, Jeffrey J. McGuire, Annemarie S. Baltay
Bluegill population demographics as related to abiotic and biotic factors in Florida lakes Bluegill population demographics as related to abiotic and biotic factors in Florida lakes
Research on Bluegills, Lepomis macrochirus R., is abundant but typically focuses on water bodies with similar environmental conditions. We assessed Bluegill density, relative abundance (catch per unit effort [CPUE] by electrofishing), growth, and size structure in 60 lakes with wide-ranging surface areas (2–12,412 ha), trophic states (oligotrophic–hypereutrophic), and macrophyte...
Authors
Andrew Kenneth Carlson, Mark V. Hoyer
An evaluation of multistate occupancy models for estimating relative abundance and population trends An evaluation of multistate occupancy models for estimating relative abundance and population trends
Detecting spatiotemporal changes in the abundances of organisms is key to effectively conserving species. While indices of abundance have long been used, there has been a shift toward model-based estimators that account for the detection process. Popular approaches including traditional occupancy models and N-mixture models entail tradeoffs. The traditional occupancy approach requires...
Authors
Valerie A. Steen, Adam Duarte, James T. Peterson
Support for the fasting endurance hypothesis of partial migration in a nearshore seabird Support for the fasting endurance hypothesis of partial migration in a nearshore seabird
Partial migration occurs when only a fraction of a population migrates instead of all individuals. Considered an evolutionary precursor to full migration, understanding why some individuals choose to undertake migration while others do not may serve to inform general migratory theory. While several hypotheses currently exist for explaining the maintenance of partial migration, empirical...
Authors
Bradley P. Wilkinson, Patrick G.R. Jodice