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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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Mortality thresholds of juvenile trees to drought and heatwaves: Implications for forest regeneration across a landscape gradient Mortality thresholds of juvenile trees to drought and heatwaves: Implications for forest regeneration across a landscape gradient

Tree loss is increasing rapidly due to drought- and heat-related mortality and intensifying fire activity. Consequently, the fate of many forests depends on the ability of juvenile trees to withstand heightened climate and disturbance anomalies. Extreme climatic events, such as droughts and heatwaves, are increasing in frequency and severity, and trees in mountainous regions must contend...
Authors
Alexadra Lalor, Darin J. Law, David D. Breshears, Donald A. Falk, Jason P. Field, Rachel A. Loehman, Jack Triepke, Greg A. Barron-Gafford

Evaluation of portable Raman spectroscopic analysis for source-rock thermal maturity assessments on bulk crushed rock Evaluation of portable Raman spectroscopic analysis for source-rock thermal maturity assessments on bulk crushed rock

This study presents a simplified method and empirical relationships for determining organic matter thermal maturity using a portable Raman system equipped with a 785 nm laser, for analysis of crushed, whole-rock samples. Suites of rocks represented by shale and coal samples with various mineralogical composition, thermal maturity, and total organic carbon (TOC) were used to test the...
Authors
Martha Stokes, Aaron M. Jubb, Paul C. Hackley, Justin E. Birdwell, Elliott P. Barnhart, Clint Scott, Jenna L. Shelton, Margaret M. Sanders, Javin J. Hatcherian

Toward invasive mussel genetic biocontrol: Approaches, challenges, and perspectives Toward invasive mussel genetic biocontrol: Approaches, challenges, and perspectives

Invasive freshwater mussels, such as the zebra (Dreissena polymorpha), quagga (Dreissena rostriformis bugensis), and golden (Limnoperna fortunei) mussel have spread outside their native ranges throughout many regions of the North American, South American, and European continents in recent decades, damaging infrastructure and the environment. This review describes ongoing efforts by...
Authors
Victor H. Hernandez Elizarraga, Scott Ballantyne, Lindsey Gengelbach, Juliana A. Americo, Steven T. Suhr, Marie-Claude Senut, Ben Minerich, Christopher M. Merkes, Thea M. Edwards, Katy E. Klymus, Cathy A. Richter, Diane L. Waller, Yale J. Passamaneck, Mauro de F. Rebelo, Daryl M. Gohl

Using explainable machine learning methods to evaluate vulnerability and restoration potential of ecosystem state transitions Using explainable machine learning methods to evaluate vulnerability and restoration potential of ecosystem state transitions

Ecosystem state transitions can be ecologically devastating or be a restoration success. State transitions are common within aquatic systems worldwide, especially considering human-mediated changes to land use and water use. We created a transferable conceptual framework to enable multiscale assessments of state resilience and early warnings of state transitions that can inform strategic
Authors
John T. Delaney, Danelle M. Larson

Bioavailability and toxicity models of copper to freshwater life: The state of regulatory science Bioavailability and toxicity models of copper to freshwater life: The state of regulatory science

Efforts to incorporate bioavailability adjustments into regulatory water quality criteria in the United States have included four major procedures: hardness-based single-linear regression equations, water-effect ratios (WERs), biotic ligand models (BLMs), and multiple-linear regression models (MLRs) that use dissolved organic carbon, hardness, and pH. The performance of each with copper...
Authors
Christopher A. Mebane

Recent, widespread nitrate decreases may be linked to persistent dissolved organic carbon increases in headwater streams recovering from past acidic deposition Recent, widespread nitrate decreases may be linked to persistent dissolved organic carbon increases in headwater streams recovering from past acidic deposition

Long-term monitoring of water quality responses to natural and anthropogenic perturbation of watersheds informs policies for managing natural resources. Dissolved organic carbon (DOC) and nitrate (NO3−) in streams draining forested landscapes provide valuable information on ecosystem function due to their biogeochemical reactivity and solubility in water. Here we evaluate a 20-year...
Authors
Kevin Alexander Ryan, Gregory B. Lawrence

Leveraging the strengths of citizen science and structured surveys to achieve scalable inference on population size Leveraging the strengths of citizen science and structured surveys to achieve scalable inference on population size

Population size is a key metric for management and policy decisions, yet wildlife monitoring programmes are often limited by the spatial and temporal scope of surveys. In these cases, citizen science data may provide complementary information at higher resolution and greater extent.We present a case study demonstrating how data from the eBird citizen science programme can be combined...
Authors
Andrew N. Stillman, Paige E. Howell, Guthrie S. Zimmerman, Emily R. Bjerre, Brian A. Millsap, Orin J. Robinson, Daniel Fink, Erica Francis Stuber, Viviana Ruiz-Gutierrez

Assay validation of saliva glucocorticoids in Columbia spotted frogs and effects of handling and marking Assay validation of saliva glucocorticoids in Columbia spotted frogs and effects of handling and marking

Non-invasive methods are important to the field of conservation physiology to reduce negative effects on organisms being studied. Glucocorticoid (GC) hormones are often used to assess health of individuals, but collection methods can be invasive. Many amphibians are imperiled worldwide, and saliva is a non- or semi-invasive matrix to measure GCs that has been partially validated for only...
Authors
Brian J. Tornabene, Blake R. Hossack, Creagh W. Breuner

Combining resilience and resistance with threat-based approaches for prioritizing management actions in sagebrush ecosystems Combining resilience and resistance with threat-based approaches for prioritizing management actions in sagebrush ecosystems

The sagebrush biome is a dryland region in the western United States experiencing rapid transformations to novel ecological states. Threat-based approaches for managing anthropogenic and ecosystem threats have recently become prominent, but successfully mitigating threats depends on the ecological resilience of ecosystems. We used a spatially explicit approach for prioritizing management...
Authors
Jeanne C. Chambers, Jessi L. Brown, John B. Bradford, Kevin Doherty, Michele R. Crist, Daniel Rodolphe Schlaepfer, Alexandra K. Urza, Karen Short

Social vulnerability and geographic access barriers to earthquake early warning education in museums and other free choice learning environments Social vulnerability and geographic access barriers to earthquake early warning education in museums and other free choice learning environments

Given the earthquake risk on the West Coast of the United States, individuals and communities require a basic understanding of ShakeAlert earthquake early warning technology, which may provide crucial seconds of warning. Free choice learning environments (FCLEs), such as museums, public libraries, and national parks, are uniquely positioned to expand the reach of earthquake early warning...
Authors
Danielle F. Sumy, Oronde Oliver Drakes, Sara McBride, Mariah R. Jenkins

Assessment of lesser prairie-chicken translocation through survival and lek surveys Assessment of lesser prairie-chicken translocation through survival and lek surveys

Translocation is a management tool used to restore or augment wildlife populations, but outcomes of translocations are often poorly documented and can have varying levels of success for improving wildlife population declines. The lesser prairie-chicken (Tympanuchus pallidicinctus) is a prairie grouse endemic to the southern Great Plains. In response to declining abundance and...
Authors
Elisabeth C. Teige, Liam A. Berigan, Carly S. H. Aulicky, Jonathan H. Reitz, David A. Haukos, Daniel S. Sullins, Kent A. Fricke, Kraig A. Schultz, Liza G. Rossi
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