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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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Experimental evaluation of spatial capture–recapture study design Experimental evaluation of spatial capture–recapture study design
A principal challenge impeding strong inference in analyses of wild populations is the lack of robust and long-term data sets. Recent advancements in analytical tools used in wildlife science may increase our ability to integrate smaller data sets and enhance the statistical power of population estimates. One such advancement, the development of spatial capture–recapture (SCR) methods...
Authors
Jillian Elizabeth Fleming, Evan H. Campbell Grant, Sean C Sterrett, Chris Sutherland
Multicriteria decisions and portfolio analysis: Land acquisition for biological and social objectives Multicriteria decisions and portfolio analysis: Land acquisition for biological and social objectives
Resource allocation for land acquisition is a common multi-objective problem that involves complex trade-offs. The National Wildlife Refuge System (NWRS) of the U.S. Fish and Wildlife Service currently uses the Targeted Resource Acquisition Comparison Tool (TRACT) to allocate funds from the Migratory Bird Conservation Fund (MBCF; established through the Migratory Bird Hunting and...
Authors
Anastasia Ihorvina Krainyk, James E. Lyons, Mindy B. Rice, Kenneth A. Fowler, Gregory J. Soulliere, Michael G. Brasher, Dale D. Humburg, John M. Coluccy
The Chesapeake Bay program modeling system: Overview and recommendations for future development The Chesapeake Bay program modeling system: Overview and recommendations for future development
The Chesapeake Bay is the largest, most productive, and most biologically diverse estuary in the continental United States providing crucial habitat and natural resources for culturally and economically important species. Pressures from human population growth and associated development and agricultural intensification have led to excessive nutrient and sediment inputs entering the Bay...
Authors
Raleigh Hood, Gary W. Shenk, Rachel L Dixon, Sean M. C. Smith, William P. Ball, Jesse Bash, R. Batiuk, Kathy Boomer, Damian C Brady, Carl Cerco, Peter Claggett, Kim de Mutsert, Zachary M. Easton, Andrew J Elmore, Marjorie A. M. Friedrichs, Lora A. Harris, Thomas F. Ihde, Iara Lacher, Li Li, Lewis C. Linker, Andrew Miller, Julia Moriarty, Gregory B. Noe, George Onyullo, Kenneth A Rose, Katherine Skalak, Richard Tian, Tamie L Veith, Lisa A. Wainger, Donald E. Weller, Yinglong J. Zhang
Supporting cost-effective watershed management strategies for Chesapeake Bay using a modeling and optimization framework Supporting cost-effective watershed management strategies for Chesapeake Bay using a modeling and optimization framework
Extensive efforts to adaptively manage nutrient pollution rely on Chesapeake Bay Program's (Phase 6) Watershed Model, called Chesapeake Assessment Scenario Tool (CAST), which helps decision-makers plan and track implementation of Best Management Practices (BMPs). We describe mathematical characteristics of CAST and develop a constrained nonlinear BMP-subset model, software, and...
Authors
Daniel E Kaufman, Gary W. Shenk, Gopal Bhatt, Kevin Asplen, Olivia H. Devereux, Jessica Rigelman, J. Hugh Ellis, Benjamin F Hobbs, Darrell J Bosch, George L Van Houtven, Arthur E McGarity, Lewis C. Linker, William P. Ball
Plant growth and biocrust-fire interactions across five North American deserts Plant growth and biocrust-fire interactions across five North American deserts
Biological soil crusts (biocrusts) are communities predominately comprised of lichens, bryophytes, fungi, algae, and cyanobacteria that form at the soil surface in dryland ecosystems worldwide. Biocrusts can influence the vascular plant community by altering surface hydrology, nutrient cycling, and the availability of microsites suitable for germination. Fire frequency has increased in...
Authors
Ellie McCann, Sasha C. Reed, Pradip Saud, Robin H. Reibold, Armin J. Howell, Akasha M. Faist
An integrated path for spatial capture–recapture and animal movement modeling An integrated path for spatial capture–recapture and animal movement modeling
Ecologists and conservation biologists increasingly rely on spatial capture–recapture (SCR) and movement modeling to study animal populations. Historically, SCR has focused on population-level processes (e.g., vital rates, abundance, density, and distribution), whereas animal movement modeling has focused on the behavior of individuals (e.g., activity budgets, resource selection...
Authors
Brett T. McClintock, Briana Abrahms, Richard Chandler, Paul B. Conn, Sarah J. Converse, Robbie Emmet, Beth Gardner, Nathan J. Hostetter, Devin S. Johnson
Belowground productivity varies by assessment technique, vegetation type, and nutrient availability in tidal freshwater forested wetlands transitioning to marsh Belowground productivity varies by assessment technique, vegetation type, and nutrient availability in tidal freshwater forested wetlands transitioning to marsh
Wetlands along upper estuaries are characterized by dynamic transitions between forested and herbaceous communities (marsh) as salinity, hydroperiod, and nutrients change. The importance of belowground net primary productivity (BNPP) associated with fine and coarse root growth also changes but remains the dominant component of overall productivity in these important blue carbon wetlands
Authors
Andrew From, Ken Krauss, Gregory B. Noe, N. Cormier, Camille Stagg, Rebecca Moss, Julie L. Whitbeck
Global-scale changes to extreme ocean wave events due to anthropogenic warming Global-scale changes to extreme ocean wave events due to anthropogenic warming
Extreme surface ocean waves are often primary drivers of coastal flooding and erosion over various time scales. Hence, understanding future changes in extreme wave events owing to global warming is of socio-economic and environmental significance. However, our current knowledge of potential changes in high-frequency (defined here as having return periods of less than 1 year) extreme wave...
Authors
Joao Morim, Sean Vitousek, Mark Hemer, Borja Reguero, Li H. Erikson, Merce Casas-Prat, Xiaolan L. Wang, Alvaro Semedo, Nobuhito Mori, Tomoya Shimura, Lorenzo Mentaschi, Ben Timmerman
A global dataset of inland fisheries expert knowledge A global dataset of inland fisheries expert knowledge
Inland fisheries and their freshwater habitats face intensifying effects from multiple natural and anthropogenic pressures. Fish harvest and biodiversity data remain largely disparate and severely deficient in many areas, which makes assessing and managing inland fisheries difficult. Expert knowledge is increasingly used to improve and inform biological or vulnerability assessments...
Authors
Gretchen L. Stokes, Abigail J. Lynch, Simon Funge-Smith, John Valbo-Jorgensen, Beard, Benjamin S. Lowe, Jesse P. Wong, Samuel J. Smidt
Regeneration trends along climate gradients in Taxodium distichum forests of the southeastern United States Regeneration trends along climate gradients in Taxodium distichum forests of the southeastern United States
The development of relict vegetation at the edges of some ecosystems has taken place particularly in environments where the regeneration of foundational species is declining. As an important stage of regeneration in the Taxodium distichum, this study explored the relationship of cone volume and seed number across environmental gradients in the Mississippi River Alluvial Valley (MRAV) and...
Authors
Beth Middleton, Ting Lei, Omag Villegas, Xiaohui Liu
Using fission-track radiography coupled with scanning electron microscopy for efficient identification of solid-phase uranium mineralogy at a former uranium pilot mill (Grand Junction, Colorado) Using fission-track radiography coupled with scanning electron microscopy for efficient identification of solid-phase uranium mineralogy at a former uranium pilot mill (Grand Junction, Colorado)
At a former uranium pilot mill in Grand Junction, Colorado, mine tailings and some subpile sediments were excavated to various depths to meet surface radiological standards, but residual solid-phase uranium below these excavation depths still occurs at concentrations above background. The combination of fission-track radiography and scanning electron microscope energy-dispersive X-ray...
Authors
Raymond H. Johnson, Susan Hall, Aaron Tigar
Timing of iceberg scours and massive ice-rafting events in the subtropical North Atlantic Timing of iceberg scours and massive ice-rafting events in the subtropical North Atlantic
High resolution seafloor mapping shows extraordinary evidence that massive (>300 m thick) icebergs once drifted >5,000 km south along the eastern United States, with >700 iceberg scours now identified south of Cape Hatteras. Here we report on sediment cores collected from several buried scours that show multiple plow marks align with Heinrich Event 3 (H3), ~31,000 years ago. Numerical...
Authors
Alan Condron, Jenna C. Hill