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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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Ten practical questions to improve data quality Ten practical questions to improve data quality

High-quality rangeland data are critical to supporting adaptive management. However, concrete, cost-saving steps to ensure data quality are often poorly defined and understood. Data quality is more than data management. Ensuring data quality requires 1) clear communication among team members; 2) appropriate sample design; 3) training of data collectors, data managers, and data users; 4)...
Authors
Sarah E. McCord, Justin L. Welty, Jennifer Courtwright, Catherine Dillon, Alexander Laurence-Traynor, Sarah H. Burnett, Ericha M. Courtright, Gene Fults, Jason W. Karl, Justin W. Van Zee, Nicholas P. Webb, Craig E. Tweedie

Possible anthropogenic enhancement of precipitation in the Sahel-Sudan Savanna by remote agricultural irrigation Possible anthropogenic enhancement of precipitation in the Sahel-Sudan Savanna by remote agricultural irrigation

The local climatic impacts of historical expansion of irrigation are substantial, but the distant impacts are poorly understood, and their governing mechanisms generally have not been rigorously analyzed. Our experiments with an earth-system model suggest that irrigation in the Middle East and South Asia may enhance rainfall in a large portion of the Sahel-Sudan Savanna (SSS) to an...
Authors
Yujin Zeng, Paul C. D. Milly, Elena Shevliakova, Sergey Malyshev, Marjolein von Huijgevoort, Krista A. Dunne

The Anthropocene as an event, not an epoch The Anthropocene as an event, not an epoch

Over the course of the last decade the concept of the Anthropocene has become widely established within and beyond the geoscientific literature but its boundaries remain undefined. Formal definition of the Anthropocene as a chronostratigraphical series and geochronological epoch following the Holocene, at a fixed horizon and with a precise global start date, has been proposed, but fails...
Authors
Philip Gibbard, Michael J.C. Walker, Andrew M Bauer, Matthew Edgeworth, Lucy E. Edwards, Erle C. Ellis, Stanley C. Finney, Jacqueline L Gill, Mark Maslin, Dorothy Merritts, William F Ruddiman

Greater than the sum of its parts: Computationally flexible Bayesian hierarchical modeling Greater than the sum of its parts: Computationally flexible Bayesian hierarchical modeling

We propose a multistage method for making inference at all levels of a Bayesian hierarchical model (BHM) using natural data partitions to increase efficiency by allowing computations to take place in parallel form using software that is most appropriate for each data partition. The full hierarchical model is then approximated by the product of independent normal distributions for the...
Authors
Devin S. Johnson, Brian M. Brost, Mevin Hooten

Nocturnal light-specific temporal partitioning facilitates coexistence for a small mesopredator, the eastern spotted skunk Nocturnal light-specific temporal partitioning facilitates coexistence for a small mesopredator, the eastern spotted skunk

Eastern spotted skunks are of conservation concern where competition and predation are a possible cause of their decline. Using camera traps at a food subsidy, we investigated nocturnal temporal overlap of spotted skunks with co-occurring predators. Spotted skunks were more active during dark nights, when their activity overlapped with the largest predator (coyotes), but not with other
Authors
Courtney J. Marneweck, Cameron R. Forehand, Charles D. Waggy, Stephen N. Harris, Todd E. Katzner, David S. Jachowski

Maximizing species distribution model performance when using historical occurrences and variables of varying persistency Maximizing species distribution model performance when using historical occurrences and variables of varying persistency

Occurrence data used to build species distribution models often include historical records from locations in which the species no longer exists. When these records are paired with contemporary environmental values that no longer represent the conditions the species experienced, the model creates false associations that hurt predictive performance. The extent of mismatching increases with...
Authors
Jason T. Bracken, Amelie Y. Davis, Katherine M. O’Donnell, William Barichivich, Susan C. Walls, Tereza Jezkova

Nitrogen enrichment during soil organic matter burning and molecular evidence of maillard reactions Nitrogen enrichment during soil organic matter burning and molecular evidence of maillard reactions

Wildfires in forested watersheds dramatically alter stored and labile soil organic matter (SOM) pools and the export of dissolved organic matter (DOM). Ecosystem recovery after wildfires depends on soil microbial communities and revegetation and therefore is limited by the availability of nutrients, such as nitrogen-containing and labile, water-soluble compounds. However, SOM byproducts...
Authors
William Bahureksa, Robert B. Young, Amy M. McKenna, Huan Chen, Kevin A. Thorn, Fernando L. Rosario-Ortiz, Thomas Borch

Linkages between land-use change and groundwater management foster long-term resilience of water supply in California Linkages between land-use change and groundwater management foster long-term resilience of water supply in California

Study Region We created a 270-m coupled model of land-use and groundwater conditions, LUCAS-W[ater], for California’s Central Coast. This groundwater-dependent region is undergoing a dramatic reorganization of groundwater management under California’s 2014 Sustainable Groundwater Management Act (SGMA).Study Focus Understanding land-use and land-cover change supports long-term sustainable...
Authors
Nathan D. Van Schmidt, Tamara Wilson, Ruth Langridge

Advanced distributed acoustic sensing vertical seismic profile imaging of an Alaska North Slope gas hydrate field Advanced distributed acoustic sensing vertical seismic profile imaging of an Alaska North Slope gas hydrate field

Gas hydrates are found in significant quantities on the North Slope of Alaska in subpermafrost sand units and intermixed in lower portions of permafrost within the hydrate stability window. While conventional surface seismic data and established imaging methods can indicate the presence of gas hydrate reservoirs, producing high-resolution images of (seismically) thin layers remains...
Authors
Cullen Young, Jeffrey Shragge, Whitney Shultz, Seth S. Haines, Can Oren, James Simmons, Timothy Collett

Geochemical and palaeomagnetic characteristics of the Vestfold Hills mafic dykes in the Prydz Bay region: implications of a Paleoproterozoic connection between East Antarctica and Proto-India Geochemical and palaeomagnetic characteristics of the Vestfold Hills mafic dykes in the Prydz Bay region: implications of a Paleoproterozoic connection between East Antarctica and Proto-India

The Archean age granite gneiss basement along the Prydz Bay coastline in East Antarctica hosts north–south-, east–west-, NE–SW- and NW–SE-trending mafic dyke swarms in the Vestfold Hills region that intruded between 2420 and 1250 Ma. The dyke trends do not show a direct correlation with the dyke geochemistry but can be broadly discriminated into high-Mg and Fe-rich tholeiites. The former...
Authors
Manoj K. Pandit, Anthony Francis Pivarunas, Joseph G Meert

Woody plant encroachment of grassland and the reversibility of shrub dominance: Erosion, fire, and feedback processes Woody plant encroachment of grassland and the reversibility of shrub dominance: Erosion, fire, and feedback processes

Many grass-dominated ecosystems in dryland regions have experienced increasing woody plant density and abundance during the past century. In many cases, this process has led to land degradation and declines in ecosystem functions. An example is the Chihuahuan Desert in the southwestern United States, which experienced different stages of shrub encroachment in the past 150 years. Among a...
Authors
Junran Li, Sujith Ravi, Guan Wang, R. Scott Van Pelt, Thomas E. Gill, Joel B. Sankey

Porewater chemistry of Louisiana marshes with contrasting salinities and its implications for coastal acidification Porewater chemistry of Louisiana marshes with contrasting salinities and its implications for coastal acidification

Dissolved inorganic carbon (DIC) and total alkalinity (TA) are fundamental components of carbonate systems that control pH and buffering capacity of the receiving water body. Three coastal marshes with contrasting salinities in Barataria Basin, Louisiana, USA, were sampled to understand seasonal changes in porewater carbonate chemistry and its impact on surrounding water bodies. Each...
Authors
Songjie He, Kanchan Maiti, Christopher Swarzenski, Tracy Elsey-Quirk, Gina Groseclose, Dubravko Justic
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