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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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A new method for bioassessment of ecosystems with complex communities and environmental gradients A new method for bioassessment of ecosystems with complex communities and environmental gradients
Bioassessment of complex and heterogeneous ecosystems is a challenge when there are multiple, strong, natural environmental gradients; unknown, or spatially varying, mixtures of stressors; and large numbers of taxa with unknown responses to both the environmental gradients and the stressors. Current methods of bioassessment are not designed for use under this set of constraints. To...
Authors
Donald R. Schoolmaster, Valerie A. Partridge
PCB concentrations in riparian spiders (Tetragnathidae) consistently reflect concentrations in water and aquatic macroinvertebrates, but not sediment: Analysis of a seven-year field study PCB concentrations in riparian spiders (Tetragnathidae) consistently reflect concentrations in water and aquatic macroinvertebrates, but not sediment: Analysis of a seven-year field study
Tetragnathid spiders have been used as sentinels to study the biotransport of contaminants between aquatic and terrestrial environments because a significant proportion of their diet consists of adult aquatic insects. A key knowledge gap in assessing tetragnathid spiders as sentinels is understanding the consistency of the year-to-year relationship between contaminant concentrations in...
Authors
Ryan R. Otter, Marc A. Mills, Ken M. Fritz, James M. Lazorchak, Dalon P. White, Gale B. Beaubien, David M. Walters
Elevated temperature and nutrients lead to increased N2O emissions from salt marsh soils from cold and warm climates Elevated temperature and nutrients lead to increased N2O emissions from salt marsh soils from cold and warm climates
Salt marshes can attenuate nutrient pollution and store large amounts of ‘blue carbon’ in their soils, however, the value of sequestered carbon may be partially offset by nitrous oxide (N2O) emissions. Global climate and land use changes result in higher temperatures and inputs of reactive nitrogen (Nr) into coastal zones. Here, we investigated the combined effects of elevated...
Authors
Sophie A. Comer-Warner, Sami Ullah, Arunabha Dey, Camille L. Stagg, Tracy Elsey-Quirk, Christopher M. Swarzenski, Fotis Sgouridis, Stefan Krause, Gail L. Chmura
Inundation tolerance, rather than drought tolerance, predicts riparian plant distributions along a local hydrologic gradient Inundation tolerance, rather than drought tolerance, predicts riparian plant distributions along a local hydrologic gradient
Riparian vegetation varies along hydrologic gradients, along which inundation and drought tend to be inversely correlated. Differentiating effects of inundation and drought on plant distributions is critical for predicting impacts of changes to baseflows and designing flow patterns to achieve vegetation objectives in regulated river systems. To this end, we conducted a greenhouse...
Authors
Bradley J. Butterfield, Emily C. Palmquist
Forest age is a primary trait filter for saproxylic beetles in the southeastern United States Forest age is a primary trait filter for saproxylic beetles in the southeastern United States
Many forests throughout the world consist of regenerating mature stands. Although these forests differ in many respects from old-growth (with a history of minimal human disturbance), they typically develop similar structural attributes over time. As a result, older mature forests may be of particular conservation value if they contain resources and microhabitats benefitting saproxylic...
Authors
Clayton Richard Traylor, Michael D. Ulyshen, Joseph V. McHugh, Ryan C. Burner
Unprecedented distribution data for Joshua trees (Yucca brevifolia and Y. jaegeriana) reveal contemporary climate associations of a Mojave Desert icon Unprecedented distribution data for Joshua trees (Yucca brevifolia and Y. jaegeriana) reveal contemporary climate associations of a Mojave Desert icon
Introduction: Forecasting range shifts in response to climate change requires accurate species distribution models (SDMs), particularly at the margins of species' ranges. However, most studies producing SDMs rely on sparse species occurrence datasets from herbarium records and public databases, along with random pseudoabsences. While environmental covariates used to fit SDMS are...
Authors
Todd Esque, Daniel F. Shryock, Gabrielle A. Berr, Felicia Chen, Lesley A. DeFalco, Sabrina Mae Lewicki, Brent Lee Cunningham, Eddie J. Gaylord, Caitlin Shannon Poage, Gretchen Elizabeth Gantz, Ross Adrian Van Gaalen, Benjamin O Gottsacker, Amanda Marie Mcdonald, J.B. Yoder, C.I. Smith, K.E. Nussear
Identifying invasive species threats, pathways, and impacts to improve biosecurity Identifying invasive species threats, pathways, and impacts to improve biosecurity
Managing invasive species with prevention and early-detection strategies can avert severe ecological and economic impacts. Horizon scanning, an evidence-based process combining risk screening and consensus building to identify threats, has become a valuable tool for prioritizing invasive species management and prevention. We assembled a working group of experts from academic, government...
Authors
Deah Lieurance, Susan Canavan, Donald C. Behringer, Amy E. Kendig, Carey R. Minteer, Lindsey S. Reisinger, Christina M. Romagosa, S. Luke Flory, Julie L. Lockwood, Patti J. Anderson, Shirley M. Baker, Jamie Bojko, Kristen E. Bowers, Kim Canavan, Kelly Carruthers, Wesley M. Daniel, Doria R. Gordon, Jeffrey E. Hill, Jennifer G. Howeth, Basil V. Iannone, Lucas Jennings, Lyn A. Gettys, Eutychus M. Kariuki, John M. Kunzer, H. Dail Laughinghouse, Nicholas E. Mandrak, Sara McCann, Tolulope Morawo, Cayla R. Morningstar, Matthew Neilson, Tabitha Petri, Ian A. Pfingsten, Robert Reed, Linda J. Walters, Christian Wanamaker
Effect of straying, reproductive strategies, and ocean distribution on the structure of American shad populations Effect of straying, reproductive strategies, and ocean distribution on the structure of American shad populations
The use of species distribution models has proliferated, providing insights for sustainable management of migratory species in a globally changing environment. However, many of these models are based on statistical relationships developed from historical conditions that may not perform well under changing or even analogous conditions caused by climate change. In this paper, we used a...
Authors
Camille Poulet, Geraldine Lassalle, Adrian Jordaan, Karin E. Limburg, Christopher C. Nack, Janet A. Nye, Andrew O’Malley, Betsy O’Malley-Barber, Dan S. Stich, John R. Waldman, Joseph D. Zydlewski, Patrick Lambert
Examining the effect of environmental variability on the viability of endangered Steller sea lions using an integrated population model Examining the effect of environmental variability on the viability of endangered Steller sea lions using an integrated population model
Understanding spatio-temporal variability in demography and the influence of environmental conditions offers insight into the factors underlying population dynamics. This is particularly true for species with divergent demographic patterns across large geographic areas. The contrasting abundance trends observed across the range of Steller sea lions (Eumetopias jubatus) have been studied...
Authors
Amanda J. Warlick, Devin S. Johnson, Katie L. Sweeney, Tom S. Gelatt, Sarah J. Converse
Habitat selection by lake trout at reefs near Drummond Island, Lake Huron: An evaluation of physical characteristics used for spawning Habitat selection by lake trout at reefs near Drummond Island, Lake Huron: An evaluation of physical characteristics used for spawning
Continued dependence on stocking of hatchery-reared lake trout, Salvelinus namaycush, in the Laurentian Great Lakes indicates recruitment bottlenecks still exist between spawning and the juvenile life stage (age-1). Possible impediments include poor habitat quality and an inability of hatchery-origin adults to select substrates that support successful incubation. Understanding of...
Authors
Steven A. Farha, Thomas R. Binder, Daniel B. Hayes, Charles R. Bronte, John Janssen, Charles C. Krueger
Stream sediment geochemistry in mineral exploration: A review of fine-fraction, clay-fraction, bulk leach gold, heavy mineral concentrate and indicator mineral chemistry Stream sediment geochemistry in mineral exploration: A review of fine-fraction, clay-fraction, bulk leach gold, heavy mineral concentrate and indicator mineral chemistry
Stream sediment surveys support early-stage reconnaissance mineral exploration and regional assessment programmes, enhanced by recent improvements in analytical method detection limits, continuously improving mineral chemistry, and new approaches to the interpretation of geochemical data. Sediment surveys may be used to predict catchment basin lithology, mineralization type based on...
Authors
Mary E Doherty, Kiel Arndt, Zhaoshan Chang, Karen D. Kelley, Owen Lavin
Neogene faulting, basin development, and relief generation in the southern Klamath Mountains (USA) Neogene faulting, basin development, and relief generation in the southern Klamath Mountains (USA)
Development and evaluation of models for tectonic evolution in the Cascadia forearc require understanding of along-strike heterogeneity of strain distribution, uplift, and upper-plate characteristics. Here, we investigated the Neogene geologic record of the Klamath Mountains province in southernmost Cascadia and obtained apatite (U-Th)/He (AHe) thermochronology of Mesozoic plutons...
Authors
Melanie J. Michalak, Susan M. Cashman, Victoria Langenheim, Taylor C. Team, Dana J. Christensen