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Publications recently added to the Pubs Warehouse

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Estimated hydrogeologic, spatial, and temporal distribution of self-supplied domestic groundwater withdrawals for aquifers of the Virginia Coastal Plain

Released June 17, 2025 10:40 EST

2025, Scientific Investigations Report 2025-5051

Matthew R. Kearns, Jason P. Pope

Water use from private-domestic wells accounts for nearly 40 percent of total groundwater withdrawals in the Virginia Coastal Plain Physiographic Province (henceforth called the Virginia Coastal Plain). However, because self-supplied domestic water use generally falls below the Virginia Department of Environmental Quality (VDEQ) reporting and management threshold of 300,000 gallons per month, quantifying these withdrawals is challenging. This report builds upon the foundation of previous U.S. Geological Survey investigations by providing revised techniques to improve estimates of the aquifer source, spatial distribution, and monthly magnitude of these groundwater withdrawals.

The aquifer sources of private-domestic wells in the Virginia Coastal Plain were estimated by cross-referencing 8,264 well records from the VDEQ and the Virginia Department of Health to a digital model of the Virginia Coastal Plain hydrogeologic framework. This analysis highlights the regional importance of the Yorktown-Eastover, Potomac, and surficial aquifers. Collectively, these three aquifers account for 80 percent of self-supplied domestic groundwater withdrawals.

The population using self-supplied domestic water was estimated using census blocks, well-use ratios, building footprints, and land-use and land-cover data to produce a high-resolution, disaggregated, raster-based dataset. This approach improves upon previous models at the census-block or road-network scale by reducing the low-density spread of the self-supplied domestic population across undeveloped areas and concentrating the population and its corresponding water use in the areas where it is most likely to occur. Results show that an estimated 475,332 people comprise the 2020 self-supplied domestic population of the Virginia Coastal Plain, an increase of 5.7 percent since 2010, and the greatest concentrations of self-supplied domestic population surround large cities. Estimates could be further refined with the addition of current and complete spatial data on public water-system service areas.

The quantity of water used by the self-supplied domestic population was estimated by modifying published state per-capita water-use coefficients with the corresponding monthly variability assessed from Virginia Coastal Plain public water-system withdrawal data. This analysis estimates an average increase of 12 percent from June through August and an average decrease of 8 percent from December through March from the baseline annual average of 80 gallons per day per capita, which generally matches similar studies in the eastern United States.

The application of these revised methodologies for the estimation of private-domestic wells and the self-supplied domestic population improves understanding of domestic groundwater use in the Virginia Coastal Plain across hydrogeologic, spatial, and temporal scales. These revisions help better inform water-resource managers and decision makers and support higher resolution groundwater modeling. Furthermore, these methods are transferrable to other areas where self-supplied domestic water withdrawals are important to the overall water budget.

Estimating daily public supply water use by drinking water service area in New Jersey

Released June 17, 2025 09:05 EST

2025, Scientific Investigations Report 2024-5061

Jennifer L. Shourds, Malia H. Scott

This report, prepared in cooperation with the New Jersey Department of Environmental Protection, presents a method for estimating daily public supply water use by drinking water service area systems for New Jersey. The ability to accurately estimate daily public supply water use could help water supply planners in New Jersey better understand and manage the state’s limited water resources and balance the competing needs for freshwater resources. Data sources for this work include daily public supply water-use data from 2016 through 2020 acquired from New Jersey American Water for 15 drinking water service areas and monthly data exported from the New Jersey Department of Environmental Protection’s online water transfer data model database (known as NJWaTr). The two datasets were compared by aggregating the daily data to a monthly timescale. Statistical regression analysis was applied to the daily data, along with climate data, to evaluate what factors are influential in estimating daily fluctuations and trends in daily public supply water use. Fifteen regression equations were developed, one for each of the 15 drinking water service area systems for which daily data were acquired. Regression equations for systems that had seasonal patterns performed better than equations for non-seasonal systems. For the test year (2020), the average adjusted coefficient of determination for the linear regression with autoregressive errors model among systems with seasonality was 0.78; the average adjusted coefficient of determination for the linear regression with autoregressive errors model among systems with little or no seasonality was 0.25. The effects of anomalous data in the regression analysis were examined by comparing adjusted coefficient of determination values when the atypical data points were removed versus when they were retained in the analysis. Overall, including the anomalous data did not have a large effect on the results, and thus the data were retained for this study. 

In addition to developing regression equations, all 589 unique drinking water service area systems in New Jersey were characterized based on socio-economic data and monthly water-use data from NJWaTr. Systems that are located near the New Jersey coast, serve populations larger than 1,970 people, or serve areas that have median property values over $256,250 tended to demonstrate seasonal water-use behaviors. Systems that have mostly urban residential land use tended to show little to no seasonal water-use behaviors. Finally, a method was developed to disaggregate monthly data to a daily timescale and was tested against systems for which daily data were not available. Two regression equation forms were developed to be applied to systems beyond the 15 systems from which the original equations were developed; one equation was developed for use when all drinking water service area systems showed little to no seasonality, and the other equation was developed for use when systems displayed seasonal behavior. 

To the extent possible, uncertainty and possible sources of error were identified and examined in relation to the regression model equations developed. Additional daily data from these 15 systems (over different years) and daily data from different systems could be used to further evaluate the results of the disaggregation through a comprehensive assessment of error. Further adjustments to the regression equations could be made, ultimately enhancing their accuracy. 

Drought and deluge— Opportunities for climate-change adaptation in US national parks

Released June 16, 2025 09:06 EST

2025, Frontiers in Ecology and the Environment

Meagan Ford Oldfather, Amber N. Runyon, Kyra Clark-Wolf, Wynne Emily Moss, Imtiaz Rangwala, Anthony Ciocco, Aparna Bamzai-Dodson, Helen Sofaer, Brian W. Miller

In a changing climate, resource management depends on anticipating changes and considering uncertainties. To facilitate effective decision making on public lands, we regionally summarized the magnitude and uncertainty of projected change in management-relevant climate variables for 332 national park units across the contiguous US. Temperature, frequency of extreme precipitation events, and drought exposure are all projected to increase within seven regions delineated in the US National Climate Assessment. In particular, the anticipated collective impacts of droughts and flooding events will lead to unique management challenges, including combinations of management actions that may seem inconsistent. Furthermore, uncertainty in the magnitude of change varied by region and climate variable considered, pointing to specific opportunities for prioritization, transferability, and innovation of climate adaptation regionally and at the park-unit scale.

Sustainability trade-offs across modeled floating solar waterscapes of the Northeastern United States

Released June 13, 2025 09:38 EST

2025, Cell Reports Sustainability

Adam Gallaher, Elizabeth L. Kalies, Steven Mark Grodsky

Expansion of floating photovoltaic (FPV) solar systems provides a low-conflict renewable energy option to help mitigate climate change while sparing land, but potential sustainability trade-offs remain unquantified. We compare the technical potential of maximum FPV deployment to address the climate crisis with FPV-buildout scenarios that prioritize biodiversity and social values across waterscapes. FPV deployment on all technically suitable waterbodies (3.5% of available sites) in the Northeastern US could generate nearly a quarter of the region’s solar energy while offsetting all the land required for solar by 2050, but trade-offs, including maintenance of freshwater biodiversity and recreational benefits, exist. Avoidance of socioenvironmental interactions yields FPV-electricity generation potential equal to a 5% increase in regional solar generation while sparing water for biodiversity and social values, though opportunities for co-location make this a conservative estimate. Our framework extends technical potential assessments to holistically inform FPV siting and support diverse Sustainable Development Goals.

Assessing nonpoint-source uranium pollution in an irrigated stream-aquifer system

Released June 13, 2025 09:30 EST

2025, Science of the Total Environment (989)

Ibraheem A. Qurban, Timothy K. Gates, Eric D. Morway, John T. Cox, Jeremy T. White, Ryan T. Bailey, Michael N. Fienen

Uranium (U) in rocks and soils of arid and semi-arid environments can be mobilized by irrigation and fertilization, posing environmental and health risks. Elevated U, along with selenium (Se) and nitrate (NO3) co-constituents, necessitates careful monitoring and management. We developed a distributed-parameter numerical model to assess U pollution in an irrigated stream-aquifer system, applying it to a 552 km2 region in Colorado's Lower Arkansas River Valley (LARV) over 14 years. A MODFLOW model, describing groundwater and stream flow, was coupled with an RT3D-OTIS model to portray reactive U transport. Calibration using the PESTPP-iES iterative ensemble smoother (iES) software indicated good agreement with observed U concentrations. The model revealed substantial and variable U levels across the LARV, highlighting potential hotspots and possible contributing factors, such as geological composition of the bedrock and near-surface shale and aquifer sediments derived from them, irrigation practices, and riparian landscape. U levels exceed the chronic standard (85th percentile = 30 μg/L, set by the US Environmental Protection Agency), which is the permissible regulatory threshold, in groundwater across 44 % of the region and along the river by an average factor of 2.9. Simulated average U concentrations in the non-riparian aquifer and river are 124 μg/L and 60 μg/L, respectively, compared with 112 μg/L and 62 μg/L for measured values. The average 85th percentile U concentration is 222 μg/L in the aquifer and 82 μg/L in the river. Average simulated U mass loading to the river is 0.17 kg/day per km, compared to an estimated 0.23 kg/day per km. Findings provide a baseline for comparing future simulated outcomes of alternative best management practices (BMPs) for U pollution mitigation and offer a methodology applicable to other irrigated regions.

Origins and fluxes of gas emissions from the Central Volcanic Zone of the Andes

Released June 13, 2025 09:19 EST

2025, Journal of Volcanology and Geothermal Research (466)

J. Maarten de Moor, Peter Barry, Alejandro Rodriguez, Felipe Aguilera, Mauricio Aguilera, Cristobal Gonzalez, Susana Layana, Agostina Chiodi, Fredy Apaza, Pablo Masias, Christoph Kern, Jaime D. Barnes, Jeffrey T. Cullen, Deborah Bastoni, Alessia Bastianoni, Martina Cascone, Christofer Jimenez, Jessica Salas-Navarro, Carlos Ramirez, Gerdhard Jessen, Donato Giovannelli, Karen Lloyd

We present geochemical data from gas samples from ∼1200 km of arc in the Central Volcanic Zone of the Andes (CVZA), the volcanic arc with the thickest (∼70 km) continental crust globally. The primary goals of this study are to characterize and understand how magmatic gases interact with hydrothermal systems, assess the origins of the major gas species, and constrain gas emission rates. To this end, we use gas chemistry, isotope compositions of H, O, He, C, and S, and SO2 fluxes from the CVZA. Gas and isotope ratios (CO2/ST, CO2/CH4, H2O/ST, δ13C, δ34S, 3He/4He) vary dramatically as magmatic gases are progressively affected by hydrothermal processes, reflecting removal and crustal sequestration of reactive species (e.g., S) and addition of less reactive meteoric and crustal components (e.g., He). The observed variations are similar in magnitude to those expected during the magmatic reactivation of volcanoes with hydrothermal systems. Carbon and sulfur isotope compositions of the highest temperature emissions (97–408 °C) are typical of arc magmatic gases. Helium isotope compositions reach values similar to upper mantle in some volcanic gases indicating that transcustal magma systems are effective conduits for volatiles, even through very thick continental crust. However, He isotopes are highly sensitive to even low degrees of hydrothermal interaction and radiogenic overprinting. Previous work has significantly underestimated volatile fluxes from the CVZA; however, emission rates from this study also appear to be lower than typical arcs, which may be related to crustal thickness.

Black abalone (Haliotis cracherodii) population density, recruitment, size structure, and population growth at Naval Base Ventura County, San Nicolas Island, California, 2013–22

Released June 13, 2025 08:54 EST

2025, Open-File Report 2025-1015

Michael C. Kenner, Julie L. Yee

The range of the endangered black abalone (Haliotis cracherodii) is divided into the North Central California region, the Central California region, the Southern California Mainland region, the Channel Islands region, and the Baja California region by the National Marine Fisheries Service for management purposes. San Nicolas Island is one of eight subregions of the Channel Islands region. The black abalone recovery plan establishes five demographic criteria for the possible delisting or downlisting of the species. The U.S. Geological Survey monitors nine long-term intertidal black abalone sites at San Nicolas Island, California, in cooperation with the U.S. Navy, which owns the island. This report uses data collected between 2013 and 2022 and the delisting criteria to analyze and describe the density, recruitment, size structure, and population trends at the nine U.S. Geological Survey monitoring sites at San Nicolas Island.

Multi-model comparison of salt marsh longevity under relative sea-level rise

Released June 13, 2025 08:52 EST

2025, Estuaries and Coasts (48)

Melinda Martinez, Kevin Buffington, Neil K. Ganju, Zafer Defne, Kate Ackerman, Karen M. Thorne, Glenn R. Guntenspergen, Joel A. Carr

Understanding salt marsh resilience under increasing sea levels can inform for management decisions. We compared temporal projections from various wetland process-based models and a geospatially derived metric (i.e., marsh lifespan) to understand key considerations and uncertainties about salt marsh resilience when using these products for decision-making. The influences of lidar topographic correction and marsh surface sediment accretion were explored across a suite of relative sea level rise (RSLR) projections to assess differences in the timing and amount of habitat change for each modeling approach. All models were run for a small coastal wetland site located in the Chesapeake Bay, Maryland, USA, to assess potential change in marsh habitat, and timing of marsh loss due to RSLR. All modeling results agreed that marsh longevity was threatened by RSLR but they varied in the time of predicted marsh submergence between the years 2070 and 2100 depending on the initial marsh surface elevation and accretion rates. Models with similar accretion rates predicted similar years until marsh submergence. Removing a positive elevation bias from lidar surveys in densely vegetated marsh areas for these models resulted in onset of submergence ~ 7 years earlier. Because there are many tradeoffs to each model type, end users need to evaluate management questions, overall goals, the amount of effort involved in model parameterization, and the amount of uncertainty in the model that they are willing to accept.

Not all spatially structured populations are metapopulations: Re-examining paradigms for a threatened shorebird

Released June 13, 2025 08:35 EST

2025, Ecological Applications (35)

Rose J. Swift, Michael J. Anteau, Kristen S. Ellis, Garrett J. MacDonald, Megan M. Ring, Mark H. Sherfy, Dustin L. Toy, David N. Koons

For at-risk species, understanding population vital rates is imperative for developing informed conservation strategies and population models. Managers often assume that species that are spatially distributed among patches of suitable habitat meet the criteria of a metapopulation. Metapopulation dynamics are determined not only by within-patch birth and death processes but also by between-patch dispersal movements of individuals that are infrequent but critical to maintaining population viability across space and time. To conserve and manage such species, an understanding of all these vital rates, including connectivity, is required. The degree to which the northern Great Plains piping plover (Charadrius melodus) breeding population functions as a metapopulation depends, in part, on the rate of movement among patchily distributed breeding areas. Here, we examined annual adult survival and breeding dispersal probabilities for 2582 individuals at two spatial scales within the northern Great Plains piping plover breeding population between 2014 and 2019. Inconsistent with a metapopulation structure, annual survival varied minimally among breeding regions but did vary across years. We also found that breeding dispersal probabilities were temporally variable, high, and unbalanced at both spatial scales examined, suggesting high connectivity in contrast to metapopulation dynamics. Further, we detected context-dependent effects of reproductive success on dispersal decisions. Individuals were more likely to disperse from the northern Missouri River to the US Alkali Wetlands following nest failure due to inundation or severe storms (including in the year prior to dispersal), whereas dispersal from the US Alkali Wetlands to the northern Missouri River decreased following successful nest attempts. Individuals also decreased dispersal from the US Alkali Wetlands to the northern Missouri River in response to renesting attempts in both the year of interest and the year prior to dispersal. Our results contradict the paradigm that northern Great Plains piping plovers are structured as a metapopulation and instead suggest a patchily distributed, likely panmictic, population. Our findings have implications for the conservation and management of this listed species and are also a general reminder that in the absence of robust knowledge of movement, spatial variation in birth and death processes across patches should not be conflated with a metapopulation structure.

Black abalone surveys at Naval Base Ventura County, San Nicolas Island, California—2022 annual report

Released June 13, 2025 07:39 EST

2025, Open-File Report 2025-1014

Michael C. Kenner, Julie L. Yee

The U.S. Geological Survey monitors a suite of intertidal black abalone (Haliotis cracherodii) sites at San Nicolas Island, California, in cooperation with the U.S. Navy, which owns the island. The nine rocky intertidal sites were established in 1980 to study the potential effect of translocated southern sea otters (Enhydra lutris nereis) on the intertidal black abalone population at San Nicolas Island. The sites were monitored, typically annually or biennially, from 1981 to 1997. Monitoring resumed in 2001 and has been completed annually thereafter. Since 2018, the monitoring has been carried out by the U.S. Geological Survey Western Ecological Research Center. The study sites became particularly important from a management perspective after a virulent disease decimated black abalone populations throughout southern California beginning in the mid-1980s. The disease, withering syndrome, was first observed on San Nicolas Island in 1992, and during the next few years, withering syndrome reduced the black abalone population on San Nicolas Island by more than 99 percent. The black abalone was subsequently listed as endangered under the Endangered Species Act in 2009.

The subject of this report is the 2022 survey of the sites and the status of the measured population of black abalone in comparison to long-term patterns (based on data collected since 1981) at San Nicolas Island. Between the years 2000 and 2022, the total monitored black abalone population on the island has grown from roughly 200 to more than 2,000, approximately a ten-fold increase following the disease-related decline. Since it was first consistently measured in 2005, the distance between adjacent black abalone has decreased substantially from approximately 50 centimeters to less than 15 centimeters, indicating that black abalone are sufficiently close together at several of the sites to reproduce successfully. The total black abalone count in 2022 was 2,156, which was 7.9 percent lower than the total count in 2020 but 6.6 percent higher than in 2021. There were increases and decreases among the sites and transects within each site in 2022, but six of the nine sites had higher counts than in the previous year. The 2022 count is one of the highest since 1993, second only to the 2020 count. In 2022, the annual recruitment rate, defined as the percentage of measured black abalone with a shell length of 3 centimeters or less, was the second highest recorded, only slightly less than in 2017.

Cascading consequences and interventions for hazards after wildfire in Okanogan County, Washington

Released June 12, 2025 17:30 EST

2025, Scientific Investigations Report 2025-5036

Briar H. Goldwyn, James R. Meldrum, Rudy M. Schuster

This report details the application of the chains of consequences method within the postfire hazard context after the 2021 Cedar Creek and Muckamuck Fires around Okanogan County, Washington. The U.S. Geological Survey Social and Economic Analysis branch convened 20 stakeholders with content- and context-specific knowledge related to these fires and their postfire hazards in an April 2023 Postfire Hazards Chains of Consequences Workshop. Guided by U.S. Geological Survey facilitators, workshop participants identified the cascading consequences of a specific postfire hazard scenario before brainstorming interventions to reduce the likelihood and severity of those consequences. The participants worked across disciplinary boundaries to identify gaps in understanding around cascading postfire hazard consequences and to brainstorm multidisciplinary interventions.

U.S. Geological Survey Pollinator Science Strategy, 2025–35—A Review and Look Forward

Released June 12, 2025 12:33 EST

2025, Circular 1556

Clint R.V. Otto, Tabitha A. Graves, Desi Robertson-Thompson, Ian Pearse, Wayne E. Thogmartin, Caroline Murphy, Lisa Webb, Sam Droege, Melanie Steinkamp, Ralph Grundel

This “U.S. Geological Survey Pollinator Science Strategy, 2025–35—A Review and Look Forward” (“Pollinator Science Strategy”) describes the science vision of the U.S. Geological Survey (USGS) to support management, conservation, and policy decisions on animal pollinators and their habitats. As the science arm of the Department of the Interior (DOI), the USGS has a primary role in providing scientific information to natural resource managers and policymakers across the United States. This “Pollinator Science Strategy” was drafted by a team of USGS pollinator researchers and was further developed through feedback from Federal, State, Tribal, nongovernmental organizations, and industry partners. This “Pollinator Science Strategy” highlights the USGS’s role in the research to promote healthy pollinator populations and address partner information gaps so they can make more informed management decisions. By outlining the importance of USGS science in addressing the information needs of other agencies, organizations, and the public, the “Pollinator Science Strategy” reaffirms the USGS’s commitment to pollinator research and showcases our research priorities for 2025–35.

With more than 300 research centers nationally, the USGS is equipped to address pollinator science across scales of complexity and geographic range. USGS pollinator science is organized according to the following five thematic areas:

  1. Assessing species ecology, distributions, and natural history requirements.
  2. Tracking species status and trends.
  3. Understanding species threats and stressors.
  4. Informing restoration and management actions.
  5. Developing novel methods for improving pollinator research, monitoring, and population outcomes that can benefit our Nation.

Our pollinator information products and associated data are made widely available to the public to ensure scientific transparency and accessibility. This “Pollinator Science Strategy” concludes with several research goals that the USGS will work towards from 2025 to 2035, representing our vision for USGS science. These research goals include synthesizing and modernizing the latest information on pollinator threats, developing research that assists managers with habitat design and restoration, providing training to partners on native bee identification and monitoring design, and developing new technologies for assessing the status and trends of our nation’s pollinators.

U.S. Geological Survey science strategy to address highly pathogenic avian influenza and its effects on wildlife health 2025–29

Released June 12, 2025 12:08 EST

2025, Circular 1558

Andrew M. Ramey, Diann J. Prosser, Laura E. Hubbard, Guelaguetza Vazquez-Meves, Amy George, M. Camille Hopkins

Executive Summary

Highly pathogenic avian influenza (HPAI) is an ecologically and economically important animal disease that can also directly affect humans (a “zoonotic” disease). HPAI was once limited almost exclusively to domestic poultry but has rapidly adapted to diverse animal hosts. Viruses causing HPAI now appear to be maintained and dispersed by wild birds largely independent of poultry, though HPAI continues to cause considerable economic losses and supply chain disruptions in the domestic poultry trade. Coincident with the adaptation of HPAI viruses to wild birds, particularly waterfowl and gulls, increasingly diverse wild bird hosts are becoming exposed to HPAI, often resulting in disease and death. More sporadically, HPAI has caused mass mortality events, particularly among seabirds. Furthermore, viral spillover to wild and domestic mammals has become more common. Spillover to wild mammals has resulted in mortality among diverse terrestrial and marine taxa, including episodic losses of such scale as to represent potential conservation challenges. Since approximately March 2024, HPAI has also affected dairy cows, which represents a new threat to the agricultural economy. Lastly, HPAI has increasingly affected humans through domestic animal exposures, exemplifying the considerable implications of this disease beyond animal health.

Rapid changes in the ecology of HPAI are currently outpacing research efforts. For example, it is not entirely clear which newly established hosts may become reservoirs for HPAI viruses (in other words, capable of maintaining HPAI viruses within a broad population indefinitely) and how this may influence viral evolution and dissemination. As a result, there are considerable information gaps regarding HPAI in wildlife that, if filled, would improve the ability of scientists, managers, agricultural industry representatives, and healthcare professionals to understand and to anticipate the effects of HPAI on wild animal, domestic animal, environmental, and human health (“One Health”).

The U.S. Geological Survey (USGS) is the lead Federal agency providing scientific research on avian influenza viruses (AIVs), including HPAI viruses, that affect wildlife for which the Department of the Interior (DOI) has management authority. States have jurisdiction over wildlife on Federal lands within their borders (43 CFR § 24.3), so the USGS Ecosystems Mission Area (EMA) coordinates with State natural resource management agencies. The EMA focuses its research on HPAI through priorities identified by the USGS Avian Influenza Science Team (app. 1). Priorities identified by the USGS Avian Influenza Science Team are based on Administration priorities, Congressional direction, and discussions with State, Federal, and Tribal natural resource management agencies that identify specific scientific gaps that need to be filled to inform sound wildlife management decisions. Notable non-DOI Federal partners include the U.S. Department of Agriculture, the lead for the HPAI regulatory response in poultry and livestock, and the Centers for Disease Control and Prevention (CDC), the lead agency for the HPAI response pertaining to human health.

The USGS offers unique expertise and capacity pertaining to research on diseases affecting free-ranging wildlife populations. This expertise has been critical to interjurisdictional surveillance and capacity-building efforts, including programs administered by the U.S. Department of Agriculture and the CDC. The USGS also provides resources, guidance, and tools to inform surveillance and interventions conducted by natural resource management agencies. More specifically, the USGS EMA provides objective and rigorous scientific data for inferring (1) the utility of new methods to detect and characterize AIVs, including those maintained in wildlife and the environment; (2) effects of HPAI on wildlife; (3) spatiotemporal patterns of wildlife host and AIV dispersal; (4) the presence and persistence of AIVs in the environment; (5) how HPAI in wildlife influences consumptive and nonconsumptive utilization of wildlife; (6) how new tools and scientific methods may promote sound management decisions for HPAI-affected wildlife, particularly species of conservation concern; and (7) the combined effects of HPAI and other stressors on ecosystem health and resiliency.

This science strategy builds upon research outlined in a previous USGS science strategy for HPAI (2016–20) by Harris and others (2016). This strategy also details research priorities identified by the Administration (for example, U.S. Department of Agriculture, 2025) and others based on USGS Avian Influenza Science Team discussions with natural resource management agencies to address HPAI and wildlife health over the next 5 years (2025–29). This strategy presents 7 goals and 26 objectives that focus USGS and partner efforts on priorities that will fill data gaps regarding the effects of HPAI on wildlife managed by or co-managed with the U.S. Department of the Interior such that agencies and partners might anticipate or limit adverse effects on public resources. This strategy also identifies research priorities intended to address HPAI in wildlife and wildlife habitat that are anticipated to support interjurisdictional One Health efforts.

Applying the resist-accept-direct (RAD) framework to wildlife health management

Released June 12, 2025 10:11 EST

2025, BioScience

Wynne Emily Moss, Gregor W. Schuurman, Emily S. Almberg, Danielle Buttke, Nathan L. Galloway, Samantha E.J. Gibbs, Anne Hubbs, Katherine Richgels, C. LeAnn White, Paul C. Cross

Wildlife diseases can have substantial impacts on wildlife populations as well as on human and domestic animal health and well-being. Although many agencies and stakeholders share a goal of supporting wildlife health, reducing wildlife disease burden is complicated by a scarcity of effective interventions for wildlife, competition for funds, and conflicting priorities. As a result, agencies are unlikely to avoid the impacts of wildlife diseases in all contexts and need to evaluate where resisting disease is most feasible and beneficial. The resist–accept–direct (RAD) framework is a tool that assists natural resource managers in exploring and communicating about management interventions, including in situations where resisting ecological changes may not be possible. In the present article, we discuss how the RAD framework could be adapted to wildlife disease contexts to address several outstanding challenges in wildlife health management.

Evaluating the influence of constructed subtidal reefs on marsh shoreline erosion, sediment deposition, and wave energy

Released June 12, 2025 08:31 EST

2025, Estuaries and Coasts (48)

Kathryn Smith, Jonathan L. Pitchford, Eric L. Sparks, Michael J. Archer, Matthew Virden, Joseph Terrano, Christopher G. Smith

Salt marshes play a critical role in providing economic and ecological benefits but are susceptible to shoreline erosion. Natural and nature-based features (NNBF), such as breakwater reefs, are often used to reduce shoreline exposure to wave action and provide biogenic benefits. However, waves and water level are also responsible for the sediment supply necessary for marsh accretion, a critical component of marsh resilience to sea level rise. The goal of this study was to evaluate the effects of two subtidal breakwater reefs on wave energy, marsh shoreline erosion, and sediment deposition onto the marsh platform. As a restoration intervention, oyster shell and limestone gravel reefs were constructed within the nearshore zone of a high-energy shoreline where active shoreline erosion is causing marsh habitat loss. Although both sediment deposition and shoreline erosion were reduced after reef installation at all sites, the reefs demonstrated a statistically significant reduction in sediment deposition, whereas its effect on decreasing shoreline erosion was less pronounced. This variability in erosion reduction may be partly influenced by the physical dimensions of the reefs, affecting wave attenuation and leeward circulation. Wave measurements indicate that the reef reduced wave energy, particularly during south and southeast winds that could lead to the largest onshore waves. Given that these strong onshore winds are seasonal, extending the duration of data collection could provide deeper insights into the reef's influence on marsh shoreline erosion. This study is novel in that there are limited experimental or observational studies quantifying the wave reduction capacity and effects of subtidal reefs on marsh shoreline erosion and sediment dynamics. Studies such as these are critical to evaluate the capacity of subtidal reefs to protect marsh shorelines from erosion, but also to measure their impact on accretion processes necessary for the marsh to maintain elevation under future sea level rise.

Assessment of continuous oil and gas resources in the Upper Cretaceous Niobrara Formation in the Southwestern Wyoming Province, Wyoming and Colorado, 2024

Released June 11, 2025 11:40 EST

2025, Fact Sheet 2025-3025

Kira K. Timm, Christopher J. Schenk, Jane S. Hearon, Thomas M. Finn, Sarah E. Gelman, Cheryl A. Woodall, Tracey J. Mercier, Andrea D. Cicero, Ronald M. Drake II, Geoffrey S. Ellis, Michael H. Gardner, Benjamin G. Johnson, Jenny H. Lagesse, Phuong A. Le, Heidi M. Leathers-Miller, Scott S. Young

 Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean continuous resources of 703 million barrels of oil and 5.8 trillion cubic feet of gas in the Niobrara Formation in the Southwestern Wyoming Province, Wyoming and Colorado.

High-pass corner frequency selection and review tool for use in ground-motion processing

Released June 11, 2025 08:49 EST

2025, Seismological Research Letters

Maria E. Ramos-Sepulveda, Scott J. Brandenberg, Tristan E. Buckreis, Grace Alexandra Parker, Jonathan P. Stewart

Raw seismological waveform data contain noise from the instrument’s surroundings and the instrument itself that can dominate recordings at low and high frequencies. To use these data in ground‐motion modeling, the effects of noise on the signals must be reduced and the signals’ usable frequency range identified. We present automated procedures to efficiently reduce low‐frequency noise that are implemented in the software package gmprocess. These procedures check for, and as needed remove, low‐frequency artifacts in the displacement record using polynomial fits, which can be used in combination with existing signal‐to‐noise ratio (SNR)‐based corner‐frequency selection procedures. The automated selections are then efficiently verified and refined using a graphical user interface (GUI) that plots relevant ground‐motion time series and spectra and tracks modifications to signal processing parameters. We demonstrate these procedures using recordings from the 2020 M 5.1 Sparta, North Carolina, and the 2013 M 4.7 southern Ontario earthquakes. Data processed with the SNR‐only and polynomial criteria for these events contain displacement artifacts in 37% and 23% of processed traces, respectively. Records with remaining artifacts are corrected manually using the GUI. These processing steps illustrate the workflow for efficient data processing with quality control.

Bioaccumulation and trophic transfer of selenium in a large oligotrophic river

Released June 11, 2025 08:18 EST

2025, Environmental Toxicology and Chemistry

Christopher A. Mebane, A. Robin Stewart, Erin Murray, Terry M. Short, Veronika Alexis Kocen, Lauren M. Zinsser

In flowing waters with elevated selenium concentrations, fish are often considered to be at risk from selenium toxicity owing to dietary exposure and accumulation in ovary tissues and subsequent deformities in developing larvae. We studied selenium throughout components of the aquatic food webs at geomorphically distinct locations along the oligotrophic Kootenai River (Montana and Idaho, USA), a river with moderately elevated dissolved selenium concentrations (~ 1 µg/L). Components included water, sediment, freshly accrued biofilms, in-situ periphyton, sestonic detritus, aquatic invertebrates, and fish, with spring and fall sampling. Selenium concentrations were similar among the sediment, biofilm, periphyton, and detritus samples with most concentrations ranging between 0.5 to 2.0 (mg/kg dry weight (dw)). Among the aquatic invertebrates, the highest selenium concentrations were observed in Paraleptophlebia sp. mayflies (>15 mg/kg dw) and oligochaetes (>30 mg/kg dw). Selenium in chironomids was higher in the spring than fall, but otherwise, no consistent concentration patterns with season or feeding traits were observed. Fish tissue selenium concentrations were highly variable among species and tissue type. Selenium in fish tissues tended to be highest in livers of rainbow trout and mountain whitefish relative to egg/ovary, muscle, and carcass tissue. With northern pikeminnow, redside shiner, and slimy sculpin, selenium concentrations tended to be highest in ovary tissues. For example, selenium in rainbow trout livers ranged from an average (range) of 37 (4.5 to 151) compared to 8.7 (2.7 to 12.3) in northern pikeminnow livers. Egg/ovary concentrations ranged from a high of 26 (10.7 to 64) in redside shiner in contrast to 12.2 (6.9 to 17) mg/kg dw in slimy sculpin. A drawback of the fish-tissue approach to monitoring and managing selenium risks in freshwaters is the need to kill multiple fish per site and event. Potential alternative monitoring approaches are illustrated using aquatic invertebrates or using the food web monitoring results to derive monitoring targets for selenium in water or invertebrate tissue that could avoid the need to kill fish to assess whether fish protection guidelines are met.

Engineering and risk research—A strategic vision for extending USGS earthquake science to risk assessment and mitigation

Released June 10, 2025 14:30 EST

2025, Circular 1555

Kishor S. Jaiswal, Sanaz Rezaeian, Nicolas Luco, N. Simon Kwong, Andrew J. Makdisi, H. Benjamin Mason, Robert E. Chase, Zachary A. Kortum

As a part of the U.S. Geological Survey (USGS) Natural Hazards Mission Area, the Engineering and Risk Project (ERP) of the Geologic Hazards Science Center conducts civil engineering research to extend natural hazards science to risk assessments. The ERP includes predominantly, but not exclusively, staff funded by the USGS Earthquake Hazards Program. A major focus of the ERP is to deliver actionable information to decisionmakers that helps promote the safety, security, and economic well-being of the Nation. The report discusses briefly the ERP’s evolution and scope, its organization structure, describes key products and deliverables, their efforts to engage with external partners, and its strategy and vision in conducting range of engineering and risk research. The research topics outlined in this report, as developed by the ERP, may be used to facilitate project planning activities during the next 10 years and serve as a longer-term planning resource for the USGS Earthquake Hazards Program and Geologic Hazards Science Center.

Distribution, abundance, and breeding activities of the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California—2024 annual report

Released June 10, 2025 11:28 EST

2025, Open-File Report 2025-1023

Scarlett L. Howell, Barbara E. Kus

Executive Summary

The purpose of this report is to provide the Marine Corps with an annual summary of the distribution, abundance, and breeding activity of the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus; flycatcher) at Marine Corps Base Camp Pendleton (MCBCP or “Base”). Surveys for the flycatcher were conducted on Base between May 8 and July 24, 2024. All of MCBCP’s historically occupied riparian habitat (core survey area) was surveyed for flycatchers in 2024. None of the non-core survey areas were surveyed in 2024.

Three transient Willow Flycatchers of unknown subspecies were observed on two of the five drainages surveyed in 2024, the Santa Margarita River and San Mateo Creek. No Willow Flycatchers were detected at Fallbrook, Las Flores, or Pilgrim Creeks. Transients in 2024 occurred in riparian scrub habitat, dominated by mule fat (Baccharis salicifolia). Exotic vegetation, primarily poison hemlock (Conium maculatum), was present in all flycatcher locations. None of the transient flycatchers were banded.

In 2024, the resident Southwestern Willow Flycatcher population on Base consisted of one unpaired female occupying one territory in the Air Station breeding area along the Santa Margarita River. No territorial males were observed in 2024. The resident flycatcher territory was located in mixed willow riparian habitat, dominated by arroyo or red willow (Salix lasiolepis or S. laevigata). The female flycatcher was originally banded as a nestling in 2020 at MCBCP, making her 4 years old in 2024.

The resident female flycatcher returned to the same breeding area and territory she occupied in 2023. Nesting was initiated in late May and continued into early August. Three nesting attempts were documented; all were unsuccessful as a result of depredation and presumed infertile eggs. No instances of Brown-headed Cowbird (Molothrus ater) parasitism were observed. The flycatcher nests were placed in two native plants, sandbar willow (S. exigua) and stinging nettle (Urtica dioica).

Two measures were initiated in recent years to attract and retain breeding flycatchers on MCBCP: a conspecific attraction playback study (initiated in 2018) and an artificial seep study (initiated in 2019); both were repeated annually through 2024. The one resident flycatcher (female) detected in 2024 occupied a territory near an automated playback unit, and nested 5 meters from an artificial seep output.

Application of mercury stable isotopes to examine sources and hydrologic factors impacting mercury bioaccumulation and cycling in invertebrates of a model saline lake

Released June 10, 2025 09:24 EST

2025, Water Research (284)

Samuel Francisco Lopez, Sarah E. Janssen, Michael T. Tate, Frank J. Black, Hannah Erin McIlwain, Laura Elizabeth Flucke, Jacob M. Ogorek, William P. Johnson

Invertebrates, such as brine shrimp and brine flies, are key prey items for millions of resident and migratory birds that utilize saline lakes such as Great Salt Lake (GSL). Elevated methylmercury (MeHg) in invertebrate and waterfowl species of GSL has been assumed to be linked to elevated MeHg in GSL’s anoxic Deep Brine Layer (DBL) where aqueous concentrations can exceed 30 ng/L. Here, we leverage mercury (Hg) concentration and stable isotope measurements on brine flies (Ephydra hians and Ephydra cinerea), brine shrimp (Artemia franciscana), and spider (western spotted orbweaver [Neoscona oaxacensis]) to examine temporal changes in Hg concentrations and sources during periods of DBL presence and absence. Mercury concentrations in brine flies were inversely correlated with lake level and directly correlated with salinity, possibly resulting from factors such as enhanced Hg bioaccumulation due to osmoregulatory stress and stunted growth and/or elevated salinities impacting composition, abundance, and Hg concentrations of food sources. DBL presence did not correspond to higher invertebrate Hg concentrations, highlighting that the DBL is not the primary source of MeHg to biota. Hg stable isotope signatures (Δ199Hg and δ202Hg) in brine shrimp varied seasonally and indicated greater cumulative photochemical Hg loss from the water column in late summer and fall months. Co-located brine fly and western spotted orbweaver samples show equivalent Δ199Hg and δ202Hg signatures, supporting Hg transfer from the aquatic to terrestrial food webs. Furthermore, Hg isotope results (Δ200Hg) indicate that the majority of Hg accumulating in GSL invertebrates is of atmospheric origin. This study highlights temporal controls on Hg bioaccumulation within GSL, which will help assess Hg cycling within the system in response to management actions and declining lake levels.

First-year survival of Lake Sturgeon reintroduced to the Maumee River

Released June 10, 2025 07:50 EST

2025, North American Journal of Fisheries Management

Jorden R. McKenna, Justin A. Chiotti, Christopher Vandergoot, Richard Kraus, Matthew Faust, Eric Weimer, Matthew Cross, William D. Hintz

Objective

Lake Sturgeon Acipenser fulvescens have experienced large population declines due to overfishing, habitat degradation, and pollution. Due to these factors, Lake Sturgeon were extirpated from the Maumee River watershed (Ohio, United States). In 2018, a 20-year reintroduction program began that aims to establish a self-sustaining population in the Maumee River. To understand the potential success of the reintroduction program, our objectives were to estimate poststocking survival of reintroduced Lake Sturgeon from age 0 to age 1. We also wanted to understand whether survival differed between age-0 Lake Sturgeon reared in a streamside facility and those reared in a traditional hatchery.

Methods

Lake Sturgeon from the two facilities were surgically implanted with acoustic transmitters; tagged fish (n = 40 per year) were released into the Maumee River in 2018, 2019, and 2021, and their movements were monitored by the Great Lakes Acoustic Telemetry Observation System.

Results

Approximately 75% of Lake Sturgeon were detected at 100 d after release and 50% were detected at 200 d after release. We found no differences in tag attrition between the two rearing strategies. Monthly survival estimates for Lake Sturgeon were 0.87 (95% CI = 0.81–0.92) in 2018, 0.97 (95% CI = 0.89–0.99) in 2019, and 0.95 (95% CI = 0.90–0.97) in 2021. No differences in survival between rearing strategies within release years existed. Annual survival estimates ranged from 0.19 to 0.71 among the three release years.

Conclusions

Our results, along with known survival rates for adult Lake Sturgeon, suggest that achieving the goal of 1,500 naturally reproducing individuals in the Maumee River is possible if reintroduced fish return to the Maumee River to spawn as adults.

Preliminary field report of landslide hazards following Hurricane Helene

Released June 09, 2025 10:45 EST

2025, Open-File Report 2025-1028

Kate E. Allstadt, Sara K. McBride, Jonathan W. Godt, Stephen L. Slaughter, Kelli W. Baxstrom, Steven Sobieszczyk, Anna Stull

Executive Summary

This report reflects our knowledge regarding the widespread landslide activity associated with Hurricane Helene observed during the U.S. Geological Survey’s (USGS) mission assignment to North Carolina in October 2024. The material in this report was originally prepared for the Federal Emergency Management Agency under mission assignment DR-4827-NC. The data and commentary in this report are reflective of a report provided to the Federal Emergency Management Agency (FEMA) on October 18, 2024, as well as information provided in briefings at the Buncombe County Emergency Operations Center. The report has been modified for public dissemination.

This assessment was based on systematic visual examination and mapping of landslide locations from aerial and satellite imagery, visual and photographic observations from low-level helicopter overflights and conversations with local landslide experts from the North Carolina Geological Survey and Appalachian Landslide Consultants PLLC, and more than 50 years of combined landslide hazard professional experience of the mission-assigned field team. No systematic field investigations were done by the USGS.

While responding to the event, the USGS did not identify any landslides that posed an immediate major threat to recovery personnel in parts of nine counties in North Carolina (Avery, Buncombe, Henderson, McDowell, Mitchell, Polk, Rutherford, Watauga, and Yancey); however, threats from renewed landslide activity may remain heightened in localized areas for months or even years. Known areas of the most abundant landslide occurrence include Bat Cave, Lake Lure, Chimney Rock, Swannanoa, Black Mountain, Fairview, steep areas in Asheville, and the Blue Ridge Parkway. The USGS shared detailed locations of known landslides with the Emergency Operations Centers. The thousands of landslide scars on hillsides and landslide deposits on flatter ground may present some threat to recovery activities. Soil and rocks will continue to erode from newly exposed landslide scars and may pose a threat to people and infrastructure who are immediately nearby. In general, the steeper and taller the landslide scar, the greater the potential threat. This threat is heightened during periods of rainfall and increases with the duration and intensity of rainstorms. Very heavy rainfall, or repeated rainfall events during short periods, could also initiate new landslides on steep slopes. Excavation of landslide deposits, particularly excavation of those deposits directly adjacent to steep slopes, may also pose a threat to nearby people and equipment.

An interagency collaborative mapping effort led by the USGS that informed this assessment identified 1,155 landslide locations by the October 2024 briefings, but that number increased to 2,217 in a final reviewed version of the locations published in January 2025. Locations were mapped from satellite imagery, fixed-wing and helicopter surveys, media and social media, and field reports in the 3 weeks following the passage of the remnants of Hurricane Helene. USGS products outlined in this report are publicly available and include geotagged photographs from aerial reconnaissance, hazard models, an interactive view of mapped landslide locations, and landslide safety and education resources.

Wake Atoll: Evaluation of plant biosecurity

Released June 08, 2025 08:57 EST

2025, Report

Corie Yanger, James D. Jacobi, Stephanie G. Yelenik, Stacie A. Hathaway

Introduced organisms can cause substantial effects across most landscapes. Island ecosystems, especially tropical islands, are at elevated risk from introduced organisms. The risks are even higher for tropical islands with moderate or high levels of transit, yet this can be minimized by application of appropriate biosecurity requirements. In this study, we examined the potential for non-native plant species introductions, especially invasive plants, via shipping containers to be transported to Wake Atoll, one of the most remote terrestrial land masses in the Pacific Ocean. We sowed debris collected from 30 shipping containers in a greenhouse experiment to determine if any live plants could be germinated, identify any species that germinated, and ascertain if they posed a threat if they were to be transported to Wake Atoll and became established there. During this study 23 plant species were identified, including ferns, monocots, and dicots. Fifteen of these species reached reproductive maturity over the course of seven months. From previous plant surveys on the atoll, we know that 13 of the 23 identified species were not previously recorded, and four species are already known to be invasive on Wake Atoll. This study provides insight into the potential for debris found in shipping containers to contribute to the spread of non-native, possibly invasive species. This information may help with the refinement of biosecurity strategies to prevent the accidental introduction of invasive species into sensitive natural areas such as Wake Atoll.

Outwash events inhibit vegetation recovery and prolong coastal vulnerability

Released June 07, 2025 09:44 EST

2025, JGR Earth Surface (130)

Jin-Si R. Over, Christopher R. Sherwood

Overwash, when high ocean water levels and waves flood a coastline, is a common phenomenon that can lead to washover deposits and barrier rollover. Outwash, by contrast, involves seaward flow, often driven by high back-barrier water levels, and can produce washout channels and nearshore deposition. Our observations show that washout channels were quickly (days to weeks) filled and reshaped into beaches, berms, and washover deposits and ponds often formed at the landward ends. However, there was a significant delay in revegetation of former washout areas compared with washover areas. North Core Banks, North Carolina, was affected by repeat hurricanes in different ways: Hurricane Florence (2018) deposited large washover fans 0.5–1 m thick, and Hurricane Dorian (2019) removed 1–4 m of sediment from washout channels. Aerial surveys captured vegetation recolonization on the Florence washover fans within a year but, after Dorian, surveys showed that although the washout channels and ponds quickly filled with marine sand, the channel throats and new washover platforms remained mostly unvegetated for five years. New vegetation growth was associated with the washout ponds and was characteristic of low-elevation hydrophilic environments. We observed comparable outcomes at washout and washover locations on the coasts of Texas and New York and suggest that outwash interrupts the normal cycle of vegetation and dune growth that is key to rebuilding barrier islands after storms. The lack of vegetation in the former washout channels prolongs vulnerability to overwash, further delaying recovery. Our findings have implications for best-management practices and modeling of coastal geomorphic evolution.

Rainfall thresholds for postfire debris-flow initiation vary with short-duration rainfall climatology

Released June 07, 2025 09:26 EST

2025, JGR Earth Surface (130)

David B. Cavagnaro, Scott W. McCoy, Donald N. Lindsay, Luke A. McGuire, Jason W. Kean, Daniel T. Trugman

The size, frequency, and geographic scope of severe wildfires are expanding across the globe, including in the Western United States. Recently burned steeplands have an increased likelihood of debris flows, which pose hazards to downstream communities. The conditions for postfire debris-flow initiation are commonly expressed as rainfall intensity-duration thresholds, which can be estimated given sufficient observational history. However, the spread of wildfire across diverse climates poses a challenge for accurate threshold prediction in areas with limited observations. Studies of mass-movement processes in unburned areas indicate that thresholds vary with local climate, such that higher rainfall rates are required for initiation in climates characterized by frequent intense rainfall. Here, we use three independent methods to test whether initiation of postfire runoff-generated debris flows across the Western United States varies similarly with climate. Through the compilation of observed thresholds at various fires, analysis of the spatial density of observed debris flows, and quantification of feature importance at different spatial scales, we show that postfire debris-flow initiation thresholds vary systematically with short-duration rainfall-intensity climatology. The predictive power of climatological data sets that are readily available before a fire occurs offers a much-needed tool for hazard management in regions that are facing increased wildfire activity, have sparse observational history, and/or have limited resources for field-based hazard assessment. Furthermore, if the observed variation in thresholds reflects long-term adjustment of the landscape to local climate, rapid shifts in rainfall intensity related to climate change will likely induce spatially variable shifts in postfire debris-flow likelihood.

The δ13C signature of dissolved organic and inorganic carbon reveals complex carbon transformations within a salt marsh

Released June 07, 2025 08:44 EST

2025, JGR Biogeosciences (130)

Meagan J. Eagle, Kevin D. Kroeger, John Pohlman, J.J. Tamborski, Z.A. Wang, Thomas W. Brooks, Jennifer A. O'Keefe Suttles, Adrian G. Mann

Coastal wetlands have high rates of atmospheric CO2 uptake, which is subsequently respired back to the atmosphere, stored as organic matter within flooded, anoxic soils, or exported to the coastal ocean. Transformation of fixed carbon occurs through a variety of subsurface aerobic and anaerobic microbial processes, and results in a large inventory of dissolved carbon. Carbon source and the roles of aerobic respiration, sulfate reduction, and methane cycling were evaluated within salt marsh peat and the underlying sandy subterranean estuary. There is a large increase in dissolved inorganic carbon (DIC, 7,350 ± 3,900 μmol L−1), dissolved organic carbon (DOC, 1,040 ± 1,480 μmol L−1) and CH4 (14.5 ± 33.3 μmol L−1) within the marsh porewaters compared to creek waters. Alkalinity production (5,730 ± 2,170 μeq L−1) and sulfate removal (1,810 ± 1,970 μmol L−1) indicate anaerobic respiration, however, relative contributions from the various decomposition pathways cannot be identified due to overlapping geochemical signatures. The δ13C of the DOC (−29.0 ± 3.7‰) and DIC (−11.2 ± 1.1‰) produced within the marsh differed from the bulk soil organic matter δ13C (−14.5 ± 0.2‰). We explore a variety of mechanisms that could result in co-occurring depleted δ13C-DOC and enriched δ13C-DIC compared to the bulk soil organic carbon pool and salt marsh vegetation, including selective mineralization, production of δ13C-depleted bacterial biomass, and methane-derived DOC. While important questions remain about carbon cycling pathways, we found evidence of a cryptic methane cycle. Alteration of the δ13C of carbon species complicates source attribution in solid and dissolved phases and careful consideration should be used when carbon is partitioned between in situ salt marsh production and external marine and terrestrial sources.

Understanding the evolution of scoria cone morphology using multivariate models

Released June 06, 2025 10:11 EST

2025, Communications Earth & Environment (6)

Gabor Kereszturi, Pablo Grosse, Melody Whitehead, Marie-Noëlle Guilbaud, Drew T. Downs, Rina Noguchi, Matthieu Kervyn

Scoria cones are the most abundant type of volcano in the Solar System. They occur in every tectonic setting and often overlap with human populations, yet our ability to provide complete geochronology within volcanic fields remains limited. Appropriate geochronology underpins the reconstruction of size-frequency distribution and is a key input for robust volcanic hazard assessment. Morphometric data have long been used to estimate relative ages of scoria cones; however, they have only shown promise at single volcanic fields and simple cones with homogenous pyroclastics. Here, we present a new global inventory of dated scoria cones (n = 572) from 71 volcanic fields formed under diverse magmatic, tectonic and climatic regimes, and build data-driven age models for dating scoria cones using easily accessible morphometric, reflectance and climatic variables. Our models suggest chemical composition of ascending magma may influence the initial scoria cone morphology which is then gradually modified by erosion over time.

Resiliency of land change monitoring efforts to input data resampling

Released June 06, 2025 10:04 EST

2025, Frontiers in Remote Sensing (6)

Nathan C. Healey, Christopher Barber, Kelcy Smith, Rohan Mital, Jesslyn F. Brown, Charles Robison

The geometric transformation of remotely sensed imagery from one map projection to another necessitates a data resampling operation which alters the recorded values. The global Landsat archive is made available in the Universal Transverse Mercator (UTM) projection system which preserves geographic shape across small area but introduces small errors in distance and area. As remote sensing-based studies develop from local scales to regional and global, they need to adopt more appropriate map projections from which accurate area measurements can be made. While effects of resampling on recorded values have been studied in the past, the impacts on higher-level results such as land cover have not been widely reported. This study investigates an approach for monitoring land cover and land change using two input datasets derived from identical source Landsat data, where one input dataset is transformed to an equal-area map projection and thereby resampled. Recorded surface reflectance values are changed through the reprojection/resampling process, and our study highlights observed differences in derived land cover from these two different input datasets throughout the various stages of deriving land cover and related characteristics. Our findings suggest that large-scale analyses of land cover will not be substantially impacted by reprojection of input data, but small-scale analyses should exercise caution when interpreting timing and magnitude of pixel-level change and classification dynamics.

Autumn as an overlooked opportunity for limnology

Released June 06, 2025 09:56 EST

2025, PLOS Climate (4)

Faith R Ferrato, Sapna Sharma, Joshua A Culpepper, Ceara J Talbot, Michael Frederick Meyer, Stephanie E. Hampton

Ecological disciplines, from forestry to soil sciences and ornithology, recognize the critical role of autumn in an array of physical and biological processes. Terrestrial studies categorize autumn as the end of the growing season. Autumn weather conditions can disrupt plant-soil interactions, affecting nutrient cycling and soil fertility [1]; determine dormancy and freezing tolerance of trees during winter [2]; and create phenological mismatches that affect diet quality and predator-prey relationships [3]. In many lakes, autumn is marked by an important period of flux within the water column, affecting nutrient cycling, phytoplankton, and fish productivity [4]. Despite their importance, autumnal limnological processes remain understudied.

An empirical Green’s function approach for isolating directivity effects in earthquake ground-motion amplitudes

Released June 06, 2025 09:54 EST

2025, Bulletin of the Seismological Society of America

Grace Alexandra Parker, Annemarie S. Baltay Sundstrom, Evan Tyler Hirakawa

In this study, we apply an empirical Green’s function (eGf) method within a ground‐motion modeling framework to mitigate trade‐offs between source, path, and site effects. Many physical processes contribute to spatial variations in observed ground motions, including earthquake radiation pattern, directivity, variable path attenuation, and site effects. Current nonergodic ground‐motion models use spatially varying coefficients for path and site effects, but they do not address trade‐offs with complex earthquake source effects. To quantify the influence of directivity on ground‐motion amplitudes, we use records from multiple smaller earthquakes with epicenters near that of a larger event. We use these small magnitude events as eGfs and estimate repeatable path and site effects at individual stations, assuming that the average adjustments are not controlled by directivity. We adjust residuals from the larger earthquake using the eGf terms, isolating effects related to the rupture. This method clearly enhances the observed broadband directivity observed in the 2022 M 5.1 and 2007 M 5.4 Alum Rock earthquake ground motions, reinforcing the conclusion that their ruptures were unilateral. For the 2004 M 6.0 Parkfield earthquake, we find a bilateral rupture model better fits the data because variations in rupture velocity, slip rate, and slip distribution seem to have a stronger effect on the ground motions than rupture direction alone. Applying eGf adjustments reduces the standard deviation of the rupture models over the three earthquakes by 32% on average and by up to 57% for the 2022 Alum Rock earthquake, confirming we have effectively removed repeatable effects related to the wave propagation path and site response. We propose a novel measure of the frequency‐dependent directivity amplification strength as the reduction in ground‐motion residual variability gained by fitting a directivity model; for the three earthquakes considered, this parameter varies between 25% and 75%, indicating that directivity can strongly influence ground motions and should be considered in ground‐motion modeling.

The first instrumentally detected hydrothermal explosion in Yellowstone National Park

Released June 06, 2025 09:36 EST

2025, Geophysical Research Letters (52)

M. Poland, Alexandra M. Iezzi, Jamie Farrell, R. Greg Vaughan

Hydrothermal explosions are one of the geological hazards most likely to impact people in Yellowstone National Park, but their frequency is poorly known. Infrasound and seismic sensors identified an explosion in Norris Geyser Basin on 15 April 2024, at 14:56 MDT (20:56 UTC)—the first instrumentally detected hydrothermal explosion in the Yellowstone region. The event affected an area tens of meters across, resulting in fractured ground, a shallow explosion crater, and a field of ejecta. There were no immediate geophysical precursors, but in the preceding years elevated discharge of thermal water altered the color, temperature, and level of a nearby small lake. Expanded seismo-acoustic monitoring in Yellowstone National Park could be useful for detecting small hydrothermal explosions and constraining their frequency, magnitude, energy release, and locations—information that could be used to better assess and mitigate hazards for the millions of people that visit the park each year.

A metadata checklist and data formatting guidelines to make eDNA FAIR (Findable, Accessible, Interoperable and Reusable)

Released June 06, 2025 09:12 EST

2025, Environmental DNA (7)

Miwa Takahashi, Tobias Frøslev Guldberg, Joana Pauperio, Bettina Thalinger, Katy E. Klymus, Caren C. Helbing, Cecilia Villacorta-Rath, Katherine Silliman, Luke R. Thompson, Sean Jungbluth, Suk Yee Yong, Stephen Killfoile Formel, Gareth Jenkins, Martin Laporte, Bruce Deagle, Sachit Rajbhandari, Thomas Jeppesen Stjernegaard, Andrew Bissett, Christopher L. Jerde, Erin E. Hahn, Lynn M. Schriml, Christopher Hunter, Peggy Newman, Peter Woollard, Lynsey R. Harper, Nicholas Dunn, Katrina West, Rachel Haderlé, Shaun Wilkinson, Neha Acharya-Patel, Mark Louie D. Lopez, Guy Cochrane, Oliver Berry

The success of environmental DNA (eDNA) approaches for species detection has revolutionized biodiversity monitoring and distribution mapping. Targeted eDNA amplification approaches, such as quantitative PCR, have improved our understanding of species distribution, and metabarcoding-based approaches have enabled biodiversity assessment at unprecedented scales and taxonomic resolution. eDNA datasets, however, are often scattered across repositories with inconsistent formats, varying access restrictions, and inadequate metadata; this limits their interoperation, reuse, and overall impact. Adopting FAIR (Findable, Accessible, Interoperable, and Reusable) data practices with eDNA data can transform the monitoring of biodiversity and individual species and support data-driven biodiversity management across broad scales. FAIR practices remain underdeveloped in the eDNA community, partly due to gaps in adapting existing vocabularies, such as Darwin Core (DwC) and Minimum Information about any (x) Sequence (MIxS), to eDNA-specific needs and workflows. To address these challenges, we propose a comprehensive FAIR eDNA (FAIRe) Metadata Checklist, which integrates existing data standards and introduces new terms tailored to eDNA workflows. Metadata are systematically linked to both raw data (e.g., metabarcoding sequences, Ct/Cq values of targeted qPCR assays) and derived biological observations (e.g., Amplicon Sequence Variant (ASV)/Operational Taxonomic Unit (OTU) tables, species presence/absence). Along with formatting guidelines, tools, templates, and example datasets, we introduce a standardized, ready-to-use approach for FAIR eDNA practices. Through broad collaboration, we seek to integrate these guidelines into established biodiversity and molecular data standards, promote journal data policies, and foster user-driven improvements and uptake of FAIR practices among eDNA data producers. In proposing this standardized approach and developing a long-term plan with key databases and data standard organizations, the goal is to enhance accessibility, maximize reuse, and elevate the scientific impact of these valuable biodiversity data resources.

Land cover change within wetland complexes at Dixie Meadows, Churchill County, Nevada: 2015 – 2023

Released June 06, 2025 08:49 EST

2025, Report

Joshua J. Caster, Joel B. Sankey, Nathaniel D. Bransky

Dixie Meadows, Nevada, is a system of geothermal springs and seeps that feed a complex of marshes and wetland meadows that are located within lands managed by the Bureau of Land Management (BLM) and the Department of Defense (DOD). A previous U.S. Geological Survey report documented variability in satellite imagery-based land cover classifications for seven wetland complexes at near monthly time intervals between October 2015 and January 2022. This report presents additional data, extending analysis to November 2023. Land cover classifications between October 2015 and November 2023 demonstrated an association between vegetation cover characteristics and surface moisture, with Class 1 having dry, bare soil or sparse upland vegetation, Class 2 having moist, bare soil or sparse to small vegetation, Class 3 having dense green vegetation with potentially saturated soil conditions, Class 4 having a mix of shallow surface water, saturated soil, and dense green vegetation, and Class 5 having open surface water. Most of the wetland complexes occur close to spring outflows primarily within land managed by the DOD, though portions are also within BLM lands. The intervening and surrounding landscape outside of the wetland complexes assessed in this study are managed by the BLM. As a result, Class 1 land covers had the largest areal coverage for BLM managed lands. Classes 2 and 3 land covers were primarily mapped inside the wetland complexes and thus had the largest area coverage within DOD managed lands. Class 4 was almost exclusively mapped within the wetland complexes and thus was largely contained within DOD managed lands. Class 5 (open water) was exclusively mapped in and adjacent to a single wetland complex with catchment ponds on land managed by the BLM. The distribution of these land cover classes over the study period was seasonally and annually variable. Land cover areas of Classes 1 and 2 were larger during the spring months. Conversely, land cover areas of Classes 3 and 4 tended to be greatest during the summer or fall. These patterns might be influenced by differences in seasonal water sources and phenology.

The Grouse & Grazing Project: Effects of cattle grazing on demographic traits of greater sage-grouse

Released June 06, 2025 08:44 EST

2025, Cooperator Science Series 170-2025

Courtney J. Conway, Cody A. Tisdale, Karen L. Launchbaugh, Bryan S. Stevens, Grace E. Overlie, Sanford D. Eigenbrode, Paul D. Makela, Shane B. Roberts

Greater sage-grouse (Centrocercus urophasianus) were once widespread within sagebrush -grassland ecosystems of western North America, but populations have declined since the mid-1960s. Though sage-grouse were not listed as threatened or endangered under the Endangered Species Act (ESA), when examined in 2015, they remain a species of interest and concern. Roughly half of the sage-grouse’s remaining habitat is on federal land, most of it managed by the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS). Livestock grazing is the most extensive land use within sage-grouse habitat and the effects of livestock grazing on sage-grouse are often debated. The extensive decade-long research project summarized in this report was initiated to provide rigorous experimental research to inform the debate regarding the relationship between livestock grazing and sage-grouse. In 2012, the Idaho Grouse & Grazing Project was started with several partners including the University of Idaho, BLM, Idaho Department of Fish and Game (IDFG), and other partners to evaluate the effects of cattle grazing on sage-grouse vital rates. Many additional supporters have provided resources to this research effort including the Public Lands Council, Idaho Cattle Association, Idaho Governor’s Office of Species Conservation, Western Association of Fish & Wildlife Agencies, U.S. Fish and Wildlife Service, USFS, and numerous grazing associations and ranchers in Idaho. This 10-year research project was a scientifically rigorous and replicated experiment, occurring across five study sites in Idaho. This document is intended to provide a summary of the findings of this unprecedented study. Annual reports are available on the project’s website: https://idahogrousegrazing.org and scientific papers are being prepared and submitted to journals. The project focused on the influence of spring cattle grazing on sage-grouse vital rates across five study sites in Idaho including 21 BLM grazing pastures. From 2014-2023, we captured 1,343 grouse, documented the fate of 1,285 nests, and tracked 399 broods. Vegetation was characterized at 4,777 plots and grazing utilization levels were recorded at >30,000 locations. Because insects are an important food source for sage-grouse hens and their chicks, insect biomass and diversity were also examined in this study. We collected arthropods in 12,151 pitfall samples and 6,217 sweep-net samples across 786 plots within our five study sites. At each study site, three or four grazing treatments were implemented after two years of pre-treatment field investigations. These controlled cattle grazing treatments included spring-grazing in even years, spring-grazing in odd years, spring-and-fall grazing in alternating years, and a no grazing (or rested) control. Once grazing treatments were implemented at a study site, we measured sage-grouse demographic traits for 4-8 years post-treatment. Stocking rate (grazing intensity) was assessed across pastures each year and was influenced by vegetation communities, topography, and water sources. Grazed pastures exhibited lower grass cover and height compared to the no grazing pastures, and the extent of this difference varied based on annual precipitation levels. Rested pastures maintained higher grass cover and grass height, but the differences in habitat structure did not consistently translate to differences in sage-grouse demographic traits. Apparent nesting success varied annually and by site, ranging from 24% to 44% over the study period. Like some other studies, results from this research show that successful (i.e., hatched) sage-grouse nests have taller grass heights than failed nests. The average grass height surrounding successful nests in grazed pastures was shorter than that surrounding successful nests in non-grazed (i.e., rested) pastures. It is well documented that grazing reduces grass height, and these observations have led to widely held assumptions that livestock grazing reduces grass height which negatively affects sage-grouse nesting habitat. At the pasture scale, this study has found that sage-grouse nesting success is no greater in pastures that were rested for 4-8 years than those currently or recently grazed. This study gives no indication that removing cattle from pastures affected nesting success. We found some evidence that nest density varied among the grazing treatments, but we did not see compelling evidence of increases in density of nesting hens following cessation of grazing in the no grazing treatments. Brood survival varied by site and year but showed no strong effect of grazing treatment. Climatic conditions, particularly drought in 2021, had a greater effect on brood survival than grazing metrics. We also found no differences in hen survival among the grazing treatments. Results of this study suggest that hens nesting in spring and fall grazed pastures had similar or even slightly higher brood survival than hens in the rested pastures or the spring grazed pastures. Arthropod biomass and species diversity varied among our study sites and the differences between grazed and rested pastures also varied among study sites. Average biomass and diversity of arthropods was higher in the spring grazed pastures on two of three sites examined but higher in the rested pastures on the other site examined. Some taxa of arthropods were more abundant in grazed pastures while other taxa were more abundant in rested pastures. For example, Carabidae (Ground Beetles) and Formicidae (Ants) had higher biomass in grazed pastures, while Tenebrionidae (Darkling Beetles) and Acrididae (Grasshoppers) had higher biomass in non-grazed pastures. Results indicate that grazing effects on arthropod biomass and arthropod diversity are study site-dependent, suggesting a need to better quantify the most important prey taxa for sage-grouse chicks and to better control for other factors that influence arthropod abundance. Based on results of this research, livestock grazing, when properly managed, does not appear to negatively impact sage-grouse nest survival or brood success. This study provides critical insights for land managers balancing livestock production with sage-grouse conservation, supporting adaptive grazing strategies that maintain both economic and ecological objectives.

Countdown to Apophis close approach—Cascading hazards from asteroid impacts

Released June 05, 2025 13:58 EST

2025, Fact Sheet 2025-3028

Tim Titus, Lori Pigue, Lucienne Morton

Introduction

Apophis (officially 99942 Apophis, pronounced “uh-PAW-fiss”) is a Near-Earth Object. Primarily composed of the materials that make up the leftover building blocks of the solar system, Near-Earth Objects are small solar system bodies in an orbit around the Sun that brings them close to the Earth. Apophis has been classified as a “potentially hazardous object,” a Near-Earth Object that may be large enough to cause significant damage in the event of an impact. Apophis is not projected to hit the Earth, but it will come close. The U.S. Geological Survey (USGS) is working with other federal partners, industry, academic institutions, and international cooperators to characterize Apophis, prepare for the flyby on Friday, April 13, 2029, and develop investigative and mitigation strategies for potential impacts from other Near-Earth Objects.

Close approaches of objects the size of Apophis (approximately 340 meters in diameter) or larger are considered rare events, occurring every few thousand years or so. Although Apophis will not impact Earth, the Specific Action Team was convened and included USGS participation, to (1) identify and quantify effects on Apophis from its close flyby with Earth; (2) assess the importance of measuring these effects; (3) categorize these effects according to different tiers of detectable limits; and (4) assess the risk to Earth of a spacecraft rendezvous with Apophis.

Paleomagnetic correlation of surface and subsurface basalt flows in the central and southwestern part of the Idaho National Laboratory, Idaho

Released June 05, 2025 13:12 EST

2025, Scientific Investigations Report 2025-5020

Mary K.V. Hodges, Allison R. Trcka, Duane E. Champion

The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, used paleomagnetic data from 22 coreholes to construct 3 fence diagrams of subsurface basalt flows in the southern part of the Idaho National Laboratory. These diagrams provide comprehensive descriptions of the horizontal and vertical distribution of basalt flows and sediment layers beneath the surface, aiding geological studies and contributing valuable data to numerical models of groundwater flow and contaminant transport. The correlations established though these diagrams include spatial correlations between basalt flows found in multiple coreholes. Correlations were identified by matching average paleomagnetic inclinations and confirming or denying these correlations using petrology, geochemistry and radiometric ages.

The fence diagrams aid in identifying potential locations of subsurface vents, volcanic vents that have been buried by more recent volcanic activity, associated to subsurface basalt flows. By tracing the subsurface flows and analyzing where the greatest thickness occurs, the locations of buried vents can be inferred. Some subsurface flows exhibit correlations across several coreholes and may indicate yet unidentified surface or buried vents, thereby enhancing our understanding of the volcanic history and subsurface geology of the region.

"Snow to Flow" postcard

Released June 05, 2025 10:12 EST

2025, General Information Product 250

Andrea L. Creighton

The U.S. Geological Survey has ongoing snowpack monitoring initiatives to help improve water availability estimates and predictions of streamflow.

A multistate capture-recapture model to estimate reproduction of North Atlantic right whales

Released June 05, 2025 09:52 EST

2025, Endangered Species Research (57) 91-102

Daniel W. Linden, Richard M Pace III, Lance P. Garrison, Jeffrey A. Hostetler, Amy R. Knowlton, Veronique Lesage, Robert A. Williams, Michael C. Runge

The recent steep decline of the endangered North Atlantic right whale Eubalaena glacialis can be attributed to high mortality combined with low reproduction. While the former is a clear result of anthropogenic activity, the latter involves more complexity. Evidence suggests that both short-term fluctuations in prey availability and long-term decline in health are responsible for depressed right whale calving rates. To facilitate an assessment of extinction risk, we developed a multistate capture-recapture model that estimated the probability of calving using extensive sightings data from 1990-2019. The model estimated sub-lethal effects of severe injury on calving probability and modeled temporal variability in calving as related to indices of prey availability (Calanus spp. biomass) and an apparent regime shift. The average annual probability of calving for known-breeding females, given average prey conditions, decreased from 0.217 [95% CI: 0.162, 0.281] to 0.142 [95% CI: 0.067, 0.252] after the 2010 regime shift. The model indicated strong evidence of a relationship between calving probability and the prey index from the eastern Gulf of Maine, although this relationship effectively disappeared after 2010; moderate evidence for a relationship with prey from the southwest Gulf of St. Lawrence remained. Weak evidence of reduced calving probability due to severe injury resulted from low sample sizes, given increased mortality for individuals observed with severe injuries. The regime effect is hypothesized to be capturing a long-term decline in health due to a combination of decreasing habitat quality resulting from climate change and potentially chronic sublethal injuries (e.g. entanglements). Our reproduction model provides demographic parameter estimates that can be used in population projections for North Atlantic right whales, although uncertainty remains in the mechanisms responsible for recent declines in calving.

Global tracking of marine megafauna space use reveals how to achieve conservation targets

Released June 05, 2025 09:49 EST

2025, Science (388) 1086-1097

Ana M.M. Sequeira, Jorge P. Rodríguez, Sarah A. Marley, Hannah J. Calich, Mirjam van der Mheen, Michelle VanCompernolle, Lucy M. Arrowsmith, Lauren R. Peel, Nuno Queiroz, Marisa Vedor, Ivo da Costa, Gonzalo Mucientes, Ana Couto, Nicolas E. Humphries, Sara Abalo-Morla, Francisco J. Abascal, Debra L. Abercrombie, Katya Abrantes, F. Alberto Abreu-Grobois, André S. Afonso, Pedro Afonso, Heidi Ahonen, Susanne Åkesson, Joanna Alfaro-Shigueto, Russel D. Andrews, Frédéric Angelier, Marina Antonopoulou, Javier A. Arata, Gonzalo Araujo, Randall Arauz, José Manuel Arcos, Igor Arregui, Haritz Arrizabalaga, Marie Auger-Méthé, Steffen Bach, Fred Bailleul, Robin W. Baird, George H. Balazs, Susan G. Barco, Adam Barnett, Warren Baverstock, Alastair M.M. Baylis, Annalea Beard, Juan Bécares, Eduardo J. Belda, Ian Bell, Ashley Bennison, Scott R. Benson, Diego Bernal, Michael L. Berumen, Sandra Bessudo, Natalia P.A. Bezerra, Antonin V. Blaison, Gabriela S. Blanco, Barbara A. Block, Mark Bolton, Mark E. Bond, Ramón Bonfil, Camrin D. Braun, Annette C. Broderick, Michael de L. Brooke, Annabelle M.L. Brooks, Edward J. Brooks, Ignacio M. Bruno, Jennifer M. Burns, Michael E. Byrne, Steven E. Campana, Hamish A. Campbell, Richard A. Campbell, Aaron Carlisle, Ruth H. Carmichael, Gemma Carroll, Paolo Casale, Filipe R. Ceia, Demian D. Chapman, Taylor K. Chapple, Jean-Benoit Charrassin, Andre Chiaradia, John Chisholm, Christopher R. Clarke, Thomas A. Clay, Christophe Cleguer, Elizabeth Clingham, Eric E. G. Clua, Jesse E.M. Cochran, Rochelle Constantine, Robert W. Cooper, Estelle Crochelet, Michelle Cronin, Eduardo Cuevas, Kayla P. DaCosta, Laurent Dagorn, Ryan Daly, Randall W. Davis, Nico P. J. de Bruyn, Carlos Delgado-Trejo, Thomas Dellinger, Solène Derville, Stella Diamant, Andrew DiMatteo, Kara L. Dodge, Philip D. Doherty, Michael C. Double, Alistair D. M. Dove, Thomas K Doyle, Michael J. Drew, Lindsay L. Dubbs, Clinton A.J. Duffy, Peter H. Dutton, Ewan W.J. Edwards, Luke D. Einoder, Mark V. Erdmann, Eduardo Espinoza, Nicole Esteban, Ana Isabel Fagundes, Chris Feare, Steven H. Ferguson, Luciana C. Ferreira, Francesco Ferretti, John Filmalter, Brittany Finucci, G. Chris Fischer, Richard J. Fitzpatrick, Jorge Fontes, Angela Formia, Sabrina Fossette, Malcolm P. Francis, Ari S. Friedlaender, Miguel Furtado, Austin J. Gallagher, Claire Garrigue, Enrico Gennari, H. Grant Gilchrist, Brendan J. Godley, Simon D. Goldsworthy, Matthew Gollock, Victoria González Carman, W. James Grecian, Jonathan R. Green, Christophe Guinet, Johan Gustafson, Tristan L. Guttridge, Hector M. Guzman, Derek Hamer, Keith C. Hamer, Neil Hammerschlag, Mike O. Hammill, Luke Harman, Emma Harrison, Catherine E. Hart, A. Errol Harris, Gordon Hastie, Fabio H.V. Hazin, Matt Heard, Alex R. Hearn, Mads Peter Heide-Jørgensen, Leeann Henry, Robert William Henry III, Vicente Guzman Hernandez, Arturo E. Herrera, Mark A. Hindell, John C. Holdsworth, Bonnie J. Holmes, Lucy A. Howey, Edgar Mauricio Hoyos Padilla, Luis A. Huckstadt, Robert E. Hueter, Paulo H. Lara, Nigel E. Hussey, Charlie Huveneers, Kevin Hyland, Dylan T. Irion, David M.P. Jacoby, Audrey Jaeger, Mohammed Y. Jaidah, Mark Jessopp, Oliver J.D. Jewell, Ryan Johnson, Carl G. Jones, Ian D. Jonsen, Lance K.B. Jordan, Salvador J. Jorgensen, Akiko Kato, James T. Ketchum, Alexander S. Kitaysky, A. Peter Klimley, Alison A. Kock, Pieter Koen, Felipe Ladino Archila, Fernanda O. Lana, Jude V. Lane, Matthieu Le Corre, Mary-Anne Lea, Eliza H.K. Leat, Olivia A. Lee, J. Jacob Levenson, César P. Ley-Quiñonez, Fiona Llewellyn, Gwen Lockhart, Gustave G. Lopez, Milagros Lopez Mendilaharsu, Andrew D. Lowther, Paolo Luschi, Molly E. Lutcavage, Warrick S. Lyon, Bruno C.L. Macena, Alice I. Mackay, Christine A. Madden Hof, Mark L. Mallory, Jeffrey C. Mangel, Michael Manning, Kate L. Mansfield, David March, Adolfo Marco, Marianne Marcoux, David Acuña-Marrero, Helene Marsh, Heather Marshall, Bruce R Mate, Jaime D. McAllister, Rebecca L. McGuire, Jane McKenzie, Lachlan McLeay, Clive R. McMahon, Michelle Modest, John T Morris, Mônica M.C. Muelbert, Naveen Namboothri, Wallace J. Nichols, Malcolm A.C. Nicoll, Bradley M. Norman, Ken Norris, Erik Olsen, Steffen Oppel, Sabine Orlowski, Anthony M. Pagano, Brad Page, Vitor H. Paiva, Daniel M. Palacios, Yannis P. Papastamatiou, Denise M. Parker, Charitha B Pattiaratchi, Hoyt Peckham, Cesar R. Peñaherrera-Palma, Julian G. Pepperell, Richard A. Phillips, Simon J. Pierce, Stephen K. Pikesley, Nicolas J. Pilcher, Patrick Pinet, Matt Pinkerton, Enrico Pirotta, Virginie Plot, Abby Powell, Kevin D. Powers, Clare E.M. Prebble, Tiana J. Preston, Rui Prieto, Laura Prosdocimi, John L. Quinn, Lina Maria Quintero, Thierry Raclot, Iván Ramirez, Dení Ramírez-Macías, Jaime A. Ramos, Andrew J. Read, Rolf Ream, Alan F. Rees, Richard D. Reina, Ryan R. Reisinger, Ohiana Revuelta, Samantha D. Reynolds, Anthony J. Richardson, Leena Riekkola, Federico G. Riet-Sapriza, David P. Robinson, Patrick W. Robinson, Carlos F.D. Rocha, Tracey L. Rogers, Christoph A. Rohner, Yan Ropert-Coudert, Monica Ross, David R. L. Rowat, Kevin Ruhomaun, Paul M. Sagar, Melita A. Samoilys, Sonia Sanchez, Alejandra G. Sandoval-Lugo, Erik A.P. dos Santos, António M. Santos, Kylie L. Scales, Gail Schofield, Jayson M. Semmens, Edy Setyawan, Scott A. Shaffer, Kartik Shanker, Marcus Sheaves, George L. Shillinger, Mahmood S. Shivji, Abraham Sianipar, Janet R.D. Silk, Mónica A. Silva, Jolene Sim, Samantha J. Simpson, Gregory B. Skomal, David J. Slip, Malcolm J. Smale, German A. Soler, Marc Soria, Lara L. Sousa, Emily J. Southall, Jean-Claude Stahl, Kilian M. Stehfest, Jeremy T. Sterling, John D. Stevens, Guy M.W. Stevens, Joshua D. Stewart, Adhith Swaminathan, Akinori Takahashi, Vikash Tatayah, Jean-Baptiste Thiebot, Paul M. Thompson, Simon R. Thorrold, Michele Thums, Jesús Tomás, Leigh G. Torres, Alison Towner, Philip N. Trathan, John P. Tyminski, Ricardo Sagarminaga van Buiten, Robert P. van Dam, Frederic Vandeperre, Nuria Varo-Cruz, Jeremy J. Vaudo, Michel Vely, Stella Villegas-Amtmann, Cecile Vincent, David Waayers, Sarah Wanless, Yuuki Y. Watanabe, Cortney A. Watt, Sam B. Weber, Nicola Weber, Michael J. Weise, Linda Welch, Randall S. Wells, Jonathan M. Werry, Bradley M. Wetherbee, Timothy D. White, Scott D. Whiting, Andrea U. Whiting, Annelise Wiebkin, Barbara Wienecke, Natalie E. Wildermann, David N. Wiley, Alexis Will, Sean Williams, Marie Windstein, Saskia Wischnewski, Matthew J. Witt, Freya C. Womersley, Andrew G. Wood, Lucy J. Wright, José C. Xavier, Takashi Yamamoto, David J. Yurkowski, Patricia M. Zarate, Alan Zavala-Norzagaray, Alexandre N. Zerbini, Daniel P. Costa, Robert Harcourt, Mark G. Meekan, Graeme C. Hays, David W. Sims, Carlos M. Duarte, Víctor M. Eguíluz

The recent Kunming-Montreal Global Biodiversity Framework (GBF) sets ambitious goals but no clear pathway for how zero loss of important biodiversity areas and halting human-induced extinction of threatened species will be achieved. We assembled a multi-taxa tracking dataset (11 million geopositions from 15,845 tracked individuals across 121 species) to provide a global assessment of space use of highly mobile marine megafauna, showing that 63% of the area that they cover is used 80% of the time as important migratory corridors or residence areas. The GBF 30% threshold (Target 3) will be insufficient for marine megafauna’s effective conservation, leaving important areas exposed to major anthropogenic threats. Coupling area protection with mitigation strategies (e.g., fishing regulation, wildlife-traffic separation) will be essential to reach international goals and conserve biodiversity.

Multi-scale spectroscopy to map intertidal microbial biofilm community and trait diversity

Released June 05, 2025 09:42 EST

2025, JGR Biogeosciences (130)

Kristin B. Byrd, Sherry L. Palacios, Nicole Chin Taylor, Isa Woo, Stacy M Moskal, Raymond F. Kokaly, Todd M. Hoefen, John Chapman, Susan E.W. De La Cruz

Intertidal microbial biofilms, or microphytobenthos, support estuarine biogeochemical cycling, the physical stability of mudflats, and food webs, particularly those of migratory shorebirds. Photosynthetic biofilms dominated by diatoms, cyanobacteria, and chlorophytes represent a significant fraction of biofilm biomass and contain pigments that can be detected with remote sensing. These diverse biofilm community types vary in indicator pigments and functional traits related to biogeochemical cycling and nutritional quality. We modeled and mapped spatial variation in intertidal biofilm distribution, quantity, diversity, and functional traits using multi-scale spectroscopic data collected within southern San Francisco Bay, California, USA (South SFB). We developed a new biofilm index (B-index) from 5 mm HySpex spectra to detect biofilm presence. We developed single and multiple response partial least squares regression (PLS) models of chlorophyll-a (chl-a; biomass indicator), indicator pigments: fucoxanthin and diadinoxanthin (diatoms), zeaxanthin (cyanobacteria), and chl-b (chlorophytes), and functional traits: carbohydrates, lipids, and total organic carbon from paired in situ biofilm data and field spectra. The B-index and PLS models were scaled to South SFB with a 3.7 m AVIRIS-NG hyperspectral image. The model %RMSE calculated from AVIRIS-NG test samples ranged from 12.7% for chl-a to 49% for chl-b; for six of the eight models, %RMSE was 23% or below. Mapped community types differed in mapped traits, with average lipid concentrations three times higher in areas indicated as diatoms compared to other groups. Available maps depict for the first time the spatial variation of an important shorebird food resource and inform the contribution of intertidal biofilm in carbon and nutrient cycling.

Hydrogeology and groundwater quality in the Snake River alluvial aquifer at Jackson Hole Airport, Wyoming, 2011–20

Released June 05, 2025 07:42 EST

2025, Scientific Investigations Report 2025-5006

Peter R. Wright, Timothy T. Bartos

The Snake River alluvial aquifer underlying the Jackson Hole Airport (JHA) in northwest Wyoming is an important source of water used for domestic, commercial, and irrigation purposes by the airport and nearby residents. The U.S. Geological Survey, in response to previously identified water-quality concerns in the area, monitored and evaluated changes in hydrogeologic characteristics and groundwater-quality conditions of the alluvial aquifer during 2011–20. During that period, the Jackson Hole Airport made several changes that potentially improved water quality at and downgradient from the airport. Well, water level, and hydrogeologic data were collected from the alluvial aquifer to identify hydrogeologic characteristic and groundwater quality changes. Additionally, results of statistical tests were applied to water-quality results to evaluate trends in selected physical properties and constituent concentrations with time. The trends of those data show that water quality did improve overall during the study period compared to previously collected data. Presumably, these trends are in response to the changes in the aircraft deicing/anti-icing fluid (ADAF) formulation used by the JHA, the many JHA infrastructure improvements made during 2011–20, the degradation of existing ADAFs in subsurface soils and groundwater, or some combination of these possibilities.

Trends in richness and occupancy of Ugandan birds and relation to local tree cover

Released June 04, 2025 09:28 EST

2025, African Journal of Ecology (63)

Ryan C. Burner, Evan M. Adams, Derek Pomeroy, Herbert Tushabe, Micheal Kibuule, Lars Jørgen Rostad, Zander S. Venter, Douglas Sheil

Changes in vegetation cover are occurring across sub-Saharan Africa and can have substantial effects on ecological communities, but limited data make understanding status and trends difficult for many taxa. We surveyed birds for several decades across Uganda using point counts. Using time-to-detection analysis in a trait-informed Bayesian multi-species occupancy framework, we model bird species richness as a function of year and local tree cover across 28 sites. We test for trends in richness and occupancy, and for the relationship between these and local and landscape-scale tree cover. Species richness increased at 75% of sites through the study period, and generalist bird species were most likely to be increasing in occupancy. Forest specialist bird species, and to a lesser extent generalists, responded positively to tree cover. Woody cover is changing across Uganda, with declines most pronounced in areas with the highest tree cover. This is likely to be causing declines in forest specialist species while favouring generalists. When tree cover decline is caused by conversion to croplands, rather than transitions to grasslands, grassland specialists are unlikely to benefit. Effects of climate and land use change and population pressure are likely to continue to alter woody plant cover and thus affect East African bird communities.

Fomites could determine severity of SARS-CoV-2 outbreaks in low-density white-tailed deer (Odocoileus virginianus) populations

Released June 04, 2025 09:28 EST

2025, Transboundary and Emerging Diseases

Elias Rosenblatt, Jonathan D. Cook, Graziella Vittoria DiRenzo, Evan H. Campbell Grant, Michael C. Runge, Brittany Mosher

The establishment of a reservoir species for zoonotic diseases is concerning for both animal and human health. Severe acute respiratory syndrome coronavirus (SARS-CoV)-2, the coronavirus responsible for the COVID-19 pandemic, has been detected in white-tailed deer (Odocoileus virginianus) in the United States. Since its initial detection, various studies have documented circulation and evolution of SARS-CoV-2 in deer, with human cases suspected of spill-back from infectious deer. A priority for mitigating SARS-CoV-2 outbreaks in deer populations is determining the contribution of direct (via aerosols and physical contact) and indirect (via contaminated objects and media) transmission pathways. We expanded existing epidemiological models founded on direct transmission pathways to include three indirect transmission pathways of infection for simulated deer populations, including contaminated water, food waste, and feed piles. Despite lower infection probabilities and transmission hazards (measured by force-of-infection (FOI)) posed solely by these indirect pathways compared to direct transmission pathways, the addition of indirect transmission pathways increased FOI, which had ramifications for the severity of SARS-CoV-2 outbreaks in simulated deer populations, particularly in populations with low degrees of spread between deer (measured by basic reproductive number; R0). We used contact rate models to estimate SARS-CoV-2 spread across deer range in the United States and identified widespread potential for indirect transmission to increase the severity of outbreaks in low-density deer populations. These results indicate that indirect transmission pathways need to be considered in the management of white-tailed deer as a reservoir species for SARS-CoV-2.

Observing northern high-latitude river systems to understand changes in a warming Arctic

Released June 04, 2025 09:03 EST

2025, Current Climate Change Reports (11)

Joshua C. Koch, J.A. O'Donnell

Purpose of Review

Streams and rivers are undergoing rapid change as the Arctic warms and thaws. We review recent observations in Arctic stream systems to identify ubiquitous changes and the most useful tools for observing change and exploring the underlying processes.

Recent Findings

Recent literature indicates increasingly significant trends in river hydrology and chemistry due to persistent warming in the Arctic and longer observational records for analysis. However, regional differences in the magnitude and direction of these trends persist. We also observe thresholds in ground thaw and surface–groundwater interactions that can impact river hydrology and chemistry.

Summary

Warming and thaw are occurring rapidly at high latitudes, resulting in increasing, yet variable responses in stream systems across regions and scales. These differences highlight the need for long-term records and an interdisciplinary approach to explain trends and predict future states. Stream systems respond to multiple landscape changes related to hydrology (changing precipitation and subsurface flow), geology (ground thaw dynamics), and ecology (vegetation change).

U.S. Geological Survey monitoring milestones—Rio Grande at Embudo, NM (08279500)

Released June 03, 2025 12:13 EST

2025, General Information Product 253

Claire E. Bunch, Melissa L. Riskin

Located at the site of the first U.S. Geological Survey (USGS) training camp for hydrographers, the Rio Grande at Embudo, NM (08279500), streamgage has been collecting water data since January 1889. The development and adaptation of equipment and techniques at this location became the foundation of USGS streamgaging methods.

Assessing causes and consequences of winter surface water dynamics in California’s Central Valley using satellite remote sensing

Released June 03, 2025 10:23 EST

2025, Journal of Flood Risk Management (18)

Christine M. Albano, Christopher E. Soulard, Blake A. Minor, Jessica J. Walker, Britt Windsor Smith, Eric K. Waller, Michael D. Bartles, Tom Corringham, Anthony T. O'Geen, Melissa M. Rohde, Anne Wein

California's Central Valley is increasingly vulnerable to winter floods. A comprehensive spatial baseline of flood extents is critical for inundation analyses that can enhance future flood predictions, but cloud cover has prevented the regular observation of surface water extents with optical satellite imagery. In this study, we leveraged the daily resolution of Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data to create a continuous series of monthly Dynamic Surface Water Extent (DSWEmod) images across the Central Valley from January 2003 to January 2023. We used the timeseries to assess the climatic driving forces of winter (Oct–April) surface water variability at sub-basin and pixel scales. At the sub-basin scale, we evaluated the influences of winter precipitation, occurrence of atmospheric rivers, and antecedent soil moisture on monthly surface water extents and found that the greatest correspondence occurs in mid-winter (Dec–Feb); in contrast, non-precipitation drivers such as water management play a stronger role in autumn and spring. The pixel-level analysis identified the probabilities of precipitation-driven surface water occurrences in the Sacramento basin are highest along rivers, conveyance channels, and floodways, with higher probabilities under wetter antecedent soil moisture conditions. Precipitation-driven surface water occurrences are also common in leveed areas and outside flood boundaries designated by state and federal agencies where exposure of structures to inundation was larger in terms of their value. Finally, areas with more frequent precipitation-driven flooding have poor recharge potential but are commonly within 5 km of areas classified as having good potential. This study demonstrates a novel approach for exploring the utility of MODIS for understanding surface water dynamics in mid-winter, a period characterized by peak precipitation, flood risk, and surface water extent. This information can provide valuable insights for (1) assessing flood risks for infrastructure and populations, (2) identifying areas most suited to strategic water management investments to increase recharge, and (3) analyzing precipitation thresholds that trigger flooding to allow proactive water management strategies to minimize damage and maximize recharge.

Assessment of active sand volumes at Rockaway Beach and Fire Island in New York and Seven Mile Island in New Jersey

Released June 03, 2025 08:42 EST

2025, Data Report 1211

Noreen A. Buster, Jennifer L. Miselis, Emily A. Wei, Arnell S. Forde

Between 2018 and 2023, the U.S. Geological Survey assessed shoreface sediment availability at three Atlantic Coast barrier island study sites in support of a National Fish and Wildlife Foundation project entitled, “Monitoring Hurricane Sandy Beach and Marsh Resilience in New York and New Jersey.” The three study sites are Seven Mile Island, New Jersey, Rockaway Beach peninsula, New York, and Fire Island, N.Y. Previously interpreted geologic boundaries from shoreface geophysical surveys and data from repeat bathymetric surveys at each of the study sites were integrated to quantify the active sediment volume, or the volume of sediment that could contribute to beach and shoreline behavior over annual to decadal time scales. This report describes the methods used to calculate these volumes and the variability of active sediment volume for each survey at the three study sites. Our data show that when shoreface volumes account for varying alongshore extent of each study site, Seven Mile Island and Rockaway Beach peninsula have about 1.5 times the active sediment volume measured at Fire Island.

Legacies of a large flood and biological control on riparian vegetation successional trajectories along a dryland braided river

Released June 03, 2025 08:03 EST

2025, River Research and Applications (41) 1169-1185

Eduardo González-Sargas, Steven R. Lee, Laura G. Perry, Patrick B. Shafroth

The interplay of disturbance and stability drives vegetation dynamics. Disturbance reduces vegetation biomass, and stability fosters its development. In riparian systems, natural disturbance is largely manifested through flood-driven fluvial processes, but other forms of disturbance, such as herbivory or fire, may influence vegetation dynamics. We studied the successional trajectories of plant communities following a 40-year flood in 2010 that significantly changed floodplain vegetation along the lower Virgin River (southwestern USA). Shortly (0–2 years) after this flood, another large disturbance event of a different nature occurred: extensive defoliation and some mortality of alien Tamarix shrubs (which dominated vegetation cover at that time in the study area) by a biological control beetle. In 2021, we resampled vegetation and topography in 439 plots that we previously monitored in 2010, 2012, 2015, and 2017 along 23 transects across five river reaches. Between 2015 and 2021, stability predominated, with only small floods (1.5- to 3-year) and limited Tamarix defoliation. By 2021, plant communities were converging, but persistent divergences existed and were associated with legacy effects of fluvial disturbance and defoliation. Native Pluchea sericea shrubs had the highest cover across all fluvial landforms. Tamarix partially recovered from defoliation, but only reached similar cover to P. sericea in plots less affected by the 40-year flood. Native Populus fremontiiProsopis pubescens, and Salix gooddingii trees, and Salix exigua shrubs, remained subordinate. Our study illustrates how successional trajectories in riparian systems depend on the nature and regime of disturbance and its legacy effects on vegetation.

Evaluation of passive samplers for cyanotoxin detection by immunoassay and chromatographic-mass spectrometry

Released June 02, 2025 13:00 EST

2025, Scientific Investigations Report 2025-5046

Brett D. Johnston, Michael D.W. Stouder, Rebecca M. Gorney, Joshua J. Rosen, Kurt D. Carpenter, Bofan Wei, Gregory L. Boyer

Harmful algal blooms, particularly cyanobacterial harmful algal blooms, threaten aquatic ecosystems, drinking water supplies, and recreational resources. In 2019, the U.S. Geological Survey, in collaboration with the New York State Department of Environmental Conservation, deployed solid phase adsorption toxin tracking (SPATT) samplers in Seneca Lake, Owasco Lake, and Skaneateles Lake to monitor the cyanotoxins microcystins, cylindrospermopsins, anatoxins, and saxitoxins. SPATT samplers can passively adsorb dissolved cyanotoxins over time, providing time-integrated data capable of detecting low concentrations of cyanotoxins that traditional discrete sampling may miss. SPATT samples were analyzed using enzyme-linked immunosorbent assay (ELISA), liquid chromatography with mass spectrometry (LC–MS), and with tandem mass spectrometry (LC–MS/MS). The effects of ELISA-required preservative on measurements by mass spectrometry methods were also evaluated.

SPATT samplers consistently detected microcystins and anatoxins more frequently than concurrent discrete sampling. ELISA results often showed higher cyanotoxin concentrations than LC–MS/MS, likely due to interference from dissolved organic matter and the ability of ELISA to detect a broader range of congeners. The addition of preservative influenced results for some analytes, particularly microcystins, which showed higher concentrations in preserved samples. Limitations in ELISA methods for cylindrospermopsins and saxitoxins were identified, potentially related to cross-reactivity, low sensitivity, or other matrix interferences. This study demonstrates the utility of SPATT samplers in capturing cyanotoxin variability, especially in environments with low cyanotoxin levels or ephemeral blooms. Further research could help improve the reliability of ELISA and other analytical methods in freshwater ecosystems.

Validation of the geometric accuracy of airborne light detection and ranging data for eastern Iowa, 2019

Released June 02, 2025 10:54 EST

2025, Open-File Report 2025-1017

Aparajithan Sampath, Jeffrey Irwin, Travis Kropuenske

A geometric accuracy assessment of lidar data collected in eastern Iowa in 2019 as part of the 3D Elevation Program (3DEP) was conducted. The assessment involved evaluating interswath accuracy, same surface precision, point density, absolute accuracy, and consistency with adjacent 3DEP datasets. The results demonstrate that the data meet or exceed the quality level 2 specifications outlined in the Lidar Base Specifications (LBS). Interswath and same surface precision values were within specified tolerances, with a root mean square difference of 0.03 meters for interswath vertical accuracy and 0.03 meters for same surface precision. Vertical accuracy in flat areas was excellent, with root mean square error values consistently below 0.10 meters. Horizontal accuracy assessments also showed good agreement between lidar and reference data. Point density generally exceeded the minimum requirement of 2 points per square meter, and the inter-project consistency assessment indicated good agreement between the Iowa lidar data and adjacent datasets.

Assessing gap-filled Landsat land surface temperature time-series data using different observational datasets

Released June 02, 2025 09:11 EST

2025, International Journal of Remote Sensing

Hua Shi, George Z. Xian

Landsat Analysis Ready Data (ARD)-based time-series present challenges in monitoring surface urban heat islands (SUHI) due to rapid changes in land surface temperature (LST) compared to cloud-free satellite observations. This research investigates the use of a spatiotemporal gap-filling model as a feasible and cost-effective solution to produce Landsat time-series LST products with both high spatial resolution and temporal frequency. The study identified and filled Landsat ARD thermal times-series data gaps due to missing data, cloud and shadow effects, and data quality. The accuracy of Landsat gap-filled products was assessed using randomly selected clear observations of Landsat and uncertainty products from the gap-filling model and was evaluated using various existing temperature datasets, including climate data from NOAA Global Historical Climate Network station observations, Daily Surface Weather and Climatological Summaries (DAYMET), and LST including MODIS, VIIRS and ECOSTRESS. The result suggests that the gap-filled Landsat LST has significant correlations with existing datasets including field observation and remote sensing data derived from other sensors that have similar monthly and seasonal variation patterns. The uncertainty maps show spatial distributions of uncertainty for gap-filled pixels that have high or low uncertainties. The Landsat gap-filled time-series datasets can be used to measure annual, seasonal, or even monthly landscape thermal conditions, which are useful for SUHI and relevant research, and to perform multi-decade time-series LST change analysis under climate change conditions.

Municipal and industrial wastewater treatment plant effluent contributions to per- and polyfluoroalkyl substances in the Potomac River: A basin-scale measuring and modeling approach

Released June 02, 2025 09:01 EST

2025, Environmental Science and Technology

Larry B. Barber, Samuel Adam Miller, Lee Blaney, Paul M. Bradley, Kaycee E. Faunce, Jacob Fleck, Malinda Frick, Ke He, Ryan D. Hollins, Conor J. Lewellyn, Emily Majcher, Mitchell A. McAdoo, Kelly Smalling

Managing per- and polyfluoroalkyl substances (PFAS) in water resources requires a basin-scale approach. Predicted environmental concentrations (PEC) and stream-vulnerability scores for PFAS were determined for the Potomac River watershed in the eastern United States. Approximately 15% of stream reaches contained municipal and/or industrial wastewater treatment plant (WWTP) discharges that are presumptive PFAS sources, comprising from <1 to >90% of streamflow. Mean annual PEC, based on the summed concentrations of eight PFAS detected in WWTP effluents (ΣPFASPEC), for all stream reaches in the watershed was 3.8 ng L–1, and stream reaches impacted by WWTP had perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) PEC of 0.39 and 0.14 ng L–1. For locations where measured-environmental concentrations (MEC) were determined, municipal and industrial WWTP contributed 7.8% (0 to 65%) of the total annual streamflow and MEC were greater than PEC in 99% of the samples, indicating additional potential PFAS sources. The mean ΣPFASPEC was 9.1 ng L–1 compared to a mean sum of PFAS MEC of 34 ng L–1. Under mean-August low-flow, 17% and 9.4% of the water-supply intakes had maximum PFOA and PFOS PEC exceeding drinking water maximum contaminant levels.

Relations of groundwater quality to long-term surface disposal of produced water near the Midway-Sunset and Buena Vista Oil Fields, California, USA

Released June 02, 2025 08:22 EST

2025, Science of the Total Environment (987)

Riley Gannon, Matthew K. Landon, Justin T. Kulongoski, Michael J. Stephens, Lyndsay B. Ball, John G. Warden, Tracy Davis, Janice M. Gillespie, Isabelle M. Cozzarelli

Contamination of groundwater by oil-field fluids in proximity to oil and gas development has been an issue of concern to water users and regulators given long histories of development and legacy disposal practices. A robust set of geochemical tracers including petroleum hydrocarbon compounds, thermogenic gases, inorganic ion concentrations, stable isotopes, radioactive isotopes, and noble gases were used to assess if oil-field fluids mixed with groundwater near the Midway-Sunset and Buena Vista Oil Fields in California, USA. Results show evidence of mixing of oil-field fluids with groundwater within the study area from either anthropogenic or natural processes. Produced water plumes associated with modern surface disposal facilities, used since the late 1950s, extend up to 1.5 km and currently remain within the boundaries of the oil fields. Plumes associated with earlier routing of produced water down natural drainages and in large retention structures (Midway Basin and Sunset Basin) near the Buena Vista Lake Bed are present in groundwater east of the oil fields. Based on geochemical tracer evidence, aerial imagery, and aerial electromagnetic surveys, these legacy plumes reach the western portion of the Central Valley aquifer system, an important groundwater resource for agricultural and domestic supply. The legacy plume associated with Sunset Basin may further be detected downgradient in deeper groundwater beneath the southern extent of the Buena Vista Lake Bed based on the presence of thermogenic gases and petroleum hydrocarbon compounds.

Effects of climate change on midwestern ecosystems: North American bog and fen

Released June 01, 2025 08:54 EST

2025, Report

Hugh Ratcliffe, Katherine Charton, Taylor Siddons, Marta P. Lyons, Olivia E. LeDee

The North American Bog and Fen ecosystem may be increasingly vulnerable to climate stressors, particularly water deficits and warming temperatures. These peat-forming wetlands, found at the southern extent of their range in the Midwest, depend on relatively stable hydrological and thermal conditions. Climate change may disrupt these conditions through projected declines in summer precipitation, increases in summer vapor pressure deficit and temperature, and longer periods of warmth throughout the year. These changes could lower water tables, accelerate aerobic decomposition, and alter peat-accumulating processes that define bogs and fens. Water deficits, compounded by warmer conditions, may reduce moss and sedge productivity and promote peat subsidence and compaction. Collectively, these impacts may compromise the structural integrity of this ecosystem and reduce its capacity to store carbon, maintain unique microhabitats, and support moisture-dependent species.

U.S. national park units as breeding bird habitat: A comparison of species prevalence and land cover across the midwestern and central United States

Released June 01, 2025 08:47 EST

2025, Science Report NPS/SR—2025/317

Ryan C. Burner, Alan A Kirschbaum, Ted Gostomski, David G Peitz

The value of national parks as bird habitat depends not only on local conditions within the parks, but also on the landscape habitat matrices in which they are located. However, the influences of local and landscape habitat matrices on birds vary by species and have not been quantified. Similarly, the trends of land cover types through time have not been systematically quantified for Midwest Region national parks and the landscapes around them, despite evidence of ongoing habitat loss exacerbated by climate change and human population growth. Managers and policy makers can use this information to understand and sustain the contribution of parks to our Nation’s avifauna.
We developed models using North American Breeding Bird Survey (BBS) data collected on routes from across the central United States. The models were used to predict occupancy of bird species of concern in 32 national park units across nine Bird Conservation Regions in the Midwest based on land cover in and around those parks. We then compared these predictions with data collected through National Park Service (NPS) bird surveys at each park to determine if bird species of concern were more or less prevalent than expected.
In each park, the mean difference between observed species detections and mean predicted detections indicates that most species are less frequently detected in the parks than predicted. However, when the range of uncertainty of predictions is considered, only 21% of park-bird combinations showed strong evidence (95%) of differing from expectation. Of these, species were less common than expected in the park in all but two cases.
These results indicate that some bird species of concern occupy sites in Midwest Region national park units at a rate roughly comparable to sites with similar land cover in the Bird Conservation Region (BCR) in which they occur. However, for one in five species-park combinations, parks appear to be less occupied than comparable sites elsewhere.

Critical minerals in orogenic (gold) and Coeur d’Alene-type mineral systems of the United States

Released May 30, 2025 11:45 EST

2025, Data Report 1198

Ryan D. Taylor, Albert H. Hofstra

Orogenic and Coeur d’Alene-type mineral systems are produced by metamorphic devolatilization of thick volcanic or siliciclastic sedimentary rock sequences and the focused flow of hydrothermal fluids upwards along crustal-scale faults. Most orogenic systems are found along the Cordilleran orogen, stretching from California northwards into Alaska, whereas most Coeur d’Alene-type systems occur in the Proterozoic Belt Basin in Idaho and Montana. Although the deposit types in these systems are exploited for precious and base metals, potential exists for the production of critical minerals necessary for current (2025) societal needs in the United States. Publicly available geochemical data compiled for these mineral systems, coupled with mineralogical characteristics, indicate that several critical minerals could potentially be recovered from unmined resources and processed mine waste: arsenic, antimony, tellurium, cobalt, and tungsten from orogenic gold deposits and zinc, antimony, arsenic, and manganese from Coeur d’Alene-type systems. These critical minerals reside primarily in arsenopyrite (arsenic), scheelite (tungsten), siderite (manganese), sphalerite (zinc), tetrahedrite (antimony and arsenic), stibnite (antimony), and telluride (tellurium) minerals.

Evaluating per- and polyfluoroalkyl substance (PFAS) prevalence and potential for biological effects in Lake Superior tributaries

Released May 30, 2025 10:28 EST

2025, Environmental Toxicology and Chemistry (44) 1723-1741

Matthew A. Pronschinske, Steven R. Corsi, Sarah M. Elliott, Martin M. Shafer, Kristen Hannon, Kaitlyn Gruber, Christina K. Remucal

Several per- and polyfluoroalkyl substances (PFAS) are Great Lakes binational chemicals of mutual concern. Although known to be persistent, data gaps regarding PFAS prevalence and biological effects exist, especially within Lake Superior’s watershed. In this 2022 study of 27 United States tributaries to Lake Superior, water samples were collected during spring runoff, summer baseflow, and fall baseflow, and stream bed-sediment samples were collected during fall. PFAS were detected in 97% of water samples and 59% of sediment samples. Summed PFAS water sample concentrations (33 analytes) were generally low relative to other environmental studies (median = 6.5 ng/L), except at Newton, Miller, and Sargent Creeks (up to 391 ng/L). Maximum water concentrations were from perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonate (PFHxS); perfluorobutanoic acid (PFBA) had the greatest median concentration. PFBA and perfluorooctanoic acid (PFOA) were most frequently detected in water samples (>90%). Summed PFAS sediment sample concentrations (33 analytes) were also generally low (median = 19 ng/kg), except at Newton and Muggun Creeks (up to 797 ng/kg). In sediment, PFOS occurred most frequently and had the greatest concentrations. The most contaminated samples came from sites with documented aqueous film forming foam or wastewater contamination; summer baseflow samples exhibited elevated PFAS concentrations. Comparison of observed water concentrations to published and derived water-quality guidelines indicated PFOS and PFHxS pose the greatest potential ecological risks. Observed PFAS mixtures may affect lipid metabolism, growth, thyroid hormones, and survival of aquatic organisms. The observed concentrations and predicted biological effects are likely underestimates of the environmental impact of PFAS. Despite low anthropogenic influence in Lake Superior’s watershed, PFAS were ubiquitous and occurred at potentially harmful concentrations.

Integrated distribution modeling resolves asynchrony between bat population impacts and occupancy trends through latent abundance

Released May 30, 2025 09:51 EST

2025, Communications Biology (8)

Bradley James Udell, Christian Stratton, Kathryn Irvine, Bethany Straw, Jonathan D. Reichard, Sarah M. Gaulke, Jeremy. T.H. Coleman, Frank C Tousley, Andrea Nichole Schuhmann, Rich D. Inman, Melinda Turner, Sarah Nystrom, Brian Reichert

Monitoring populations is challenging for cryptic species with seasonal life cycles, where data from multiple field techniques are commonly collected and analyzed as multiple lines of evidence. Data integration can provide comprehensive inferences while improving accuracy, precision, and scope but faces challenges in modeling misaligned resolutions and observational uncertainties. We developed a multi-scale, integrated species distribution model (MS-iSDM) for North American bats to combine data across monitoring types and seasons using joint likelihood methods, observational models with false-negatives and false-positives, and seasonal migratory connectivity. We applied this model to 11 years of data for an imperiled bat species (tricolored bat, Perimyotis subflavus). Relative abundance and occupancy were linked with multi-scale predictors, revealing clear patterns of population declines, but with important differences in spatial trends (abundance: corresponded with white-nose syndrome impacts, occupancy: at the range periphery) and overall severity (abundance: -74.8%, 95% CRI: -79.7% to -69.3%; occupancy: -35.5%, 95% CRI: -41.1% to -30.2%). The asynchrony between occupancy trends and population impacts was explained as an emergent pattern of spatiotemporal variation in abundance in the integrated distribution model. Compared to multiple lines of evidence, the integrated model provided consensus-estimates, increased precision and spatiotemporal scope, and strengthened evidence of population declines.

Foundational uncertainties in terminal Ediacaran chronostratigraphy revealed by high-precision zircon U-Pb geochronology of the Nama Group, Namibia

Released May 30, 2025 09:42 EST

2025, Earth-Science Reviews (268)

Fred T. Bowyer, Fabio Messori, Rachel Wood, Ulf Linnemann, Esther Rojo-Perez, Mandy Zieger-Hofmann, Johannes Zieger, Junias Ndeunyema, Martin Shipanga, Bontle Mataboge, Dan Condon, Catherine V. Rose, Collen-Issia Uahengo, Sean Patrick Gaynor, Inigo A. Müller, Gerd Geyer, Torsten W. Vennemann, Joshua H.F.L. Davies, Maria Ovtcharova

The Nama Group of southern Namibia and northwestern South Africa hosts the best-dated mixed carbonate-siliciclastic foreland basin succession of the terminal Ediacaran [ca. 551 million years (Ma) ago to <538 Ma] and is key for resolving the chronology of early metazoan evolution. Numerous silicified volcanic tuff interbeds are present, but differing interpretations regarding the fidelity of their ages lead to different regional stratigraphic correlations, especially for the Urusis Formation of the Schwarzrand Subgroup. An expanded record of the Urusis Formation is found in the Swartpunt area of southern Namibia, which has yielded an important metazoan biota. But the succession in this area is preserved as a series of thrusts at the leading edge of the Gariep orogenic belt and zircon U-Pb data show systematic age repetition. We use regional stratigraphic and structural mapping, integrated with carbonate carbon isotope (δ13Ccarb) chemostratigraphy and high-precision radioisotope U-Pb zircon geochronology from outcrop and recently acquired drill core to develop a temporally calibrated basin-wide depositional model. This integrated dataset either reflects complex zircon reworking, inheritance, or potential analytical biases (Scenario 1) or the presence of a Gariep-related cryptic décollement within the Spitskop Member that has resulted in stratigraphic repetition (Scenario 2). We investigate the evidence for and against both scenarios and consider their implications for stratigraphic and δ13Ccarb correlations between the Swartpunt area and coeval exposures along the Orange River border with South Africa.
Given that these issues are in an area that hosts numerous silicified ash beds and extensive exposure, an inability to confidently discount either scenario highlights a level of compounding uncertainty in zircon U-Pb geochronology that must be considered when attempting to build global chronostratigraphic frameworks. Scenario 1 implies that some of the weighted mean ages and Bayesian eruption ages from the Swartpunt area may be >1 Myr older than the depositional age of their respective ash beds when assuming existing stratigraphic correlations. If this scenario is preferred, then a cautious approach would be to consider all weighted mean zircon U-Pb ages from ash beds to reflect maximum depositional ages. Both scenarios support deposition of the Huns Member >540 Ma in the Swartpunt area if the oldest weighted mean age reported here represents a near-depositional age, which has significant implications for the temporal calibration of important terminal Ediacaran ichnofossil assemblages and future cyclostratigraphic studies.
Stratigraphic correlations common to both scenarios allow us to temporally calibrate a basin evolution model for the Nama Group. Temporal trends in initial hafnium isotope (εHf) compositions of zircon grains from ash beds throughout the succession may support progressive crustal thickening associated with underplating of the Damara orogenic belt along the northern periphery of the Kalahari craton from ca. 547 Ma to ca. 538 Ma. The compilation of new and published zircon U-Pb ages may also imply that the locus of carbonate platform development migrated from north to south (present co-ordinates), tracking the migration of foredeep subsidence.

Tree swallow (Tachycineta bicolor) demographics and metal(loid) concentrations in egg contents from the Kootenai River basin, Montana nest box colonies

Released May 30, 2025 08:50 EST

2025, Environmental Monitoring and Assessment (197)

Brian C. Balmer, Joseph P. Skorupa, Katherine B. Adams, Bridger M. Creel, Gregory C. Hoffman, Megan A. Fylling, Stephanie Le, Jacob M. Martin, W. Scott McBride, Jacob T. Williams, Travis S. Schmidt

Selenium (Se) levels in water have been increasing in Lake Koocanusa and the Kootenai River below Libby Dam in Montana due to coal mining in the drainage basin of the Elk River, British Columbia. Aquatic monitoring of Se is ongoing to assess potential effects; however, exposure to terrestrial, aquatic-dependent wildlife has not been investigated. Tree swallows are a targeted receptor for evaluation of potential Se-related effects as this species is a mid-level consumer with aquatic-terrestrial food web linkages, is sensitive to Se, and reliably uses nest boxes. The goals of this project were to identify tree swallow demographics and metal(loid) concentrations to assess potential species and ecosystem-level effects within the Kootenai River basin study area. During 2022 and 2023, a total of 98 nest boxes were monitored across ~ 120 km of shoreline; 60 eggs were collected. Egg metal(loid) concentrations, including Se, were below levels identified to cause reproductive effects in avian species. However, nest box occupancy increased with distance from the US/Canada border (P < 0.001; R2 = 0.83), and Se concentrations were significantly higher (P = 0.014) in 2023 than 2022 (3.2 (3.0–3.4) and 2.8 (2.6–3.1), respectively; geometric mean, 95% CI; mg/kg, dw). With ongoing mining operations in the drainage basin of the Elk River, these results suggest that long-term monitoring of tree swallows will support assessment of spatiotemporal metal(loid) trends. Additional data, including tree swallow foraging patterns, will allow evaluation of differences in nest box occupancy and metal(loid) concentrations in the Kootenai River basin.

Wildfire risk information sources and the acceptability of fuels treatments near select WUI communities in the Western United States

Released May 30, 2025 08:10 EST

2025, Journal of Forest Policy and Economics (176)

Kelly Wallace, Hannah Brenkert-Smith, Patricia A. Champ, James R. Meldrum, Grant Webster, Christine Taniguchi, Julia B. Goolsby, Colleen Donovan, Carolyn Wagner, Christopher M. Barth, Josh Kuehn, Suzanne Wittenbrink

Fuels treatments intended to reduce fuel loads and improve forest health on public lands offer one way to reduce wildfire hazards in the wildland-urban interface (WUI), where the natural and built environments meet. However, for fuels treatment implementation to be successful, it must comply with regulatory and scientific standards and be supported by local communities, as lack of acceptance can lead to alterations, delays, or abandonment. To foster support, public land managers can engage directly with residents in communities near treatment areas through various communication channels or engage indirectly through trusted local partners. This research uses paired household survey and observed parcel-level wildfire risk assessment data to investigate wildfire risk information sources' role in the acceptability of fuels treatment approaches on public lands near select WUI communities in the Western United States. We find that information deemed useful from sources is often positively correlated with acceptability, while information deemed not useful is sometimes negatively correlated. Local sources of information tend to be widely received, perceived as useful, and have positive correlations with acceptability, while nonlocal sources vary in their receipt, perceived usefulness, and correlations with acceptability. Public land managers, particularly those from national organizations, may benefit from leveraging and aligning messaging with trusted local partners. Developing fuels treatment plans that consider existing local sentiments may facilitate public trust in managers and acceptability of treatments.

Critical minerals in mine waste

Released May 30, 2025 08:00 EST

2025, Fact Sheet 2025-3026

Nadine Piatak, Sarah Jane White, Sarah Hayes, Robert R. Seal, II

Introduction 

Critical minerals are commodities with vulnerable supply chains that play a vital role in supporting the United States’ economy, national defense and security, emerging technologies, and energy independence. The prosperity of our Nation depends on generating a resilient supply of domestic critical minerals; mine waste may be an untapped source of these commodities. Mine waste from centuries of legacy mining persist on the landscape and may contain critical minerals and other valuable commodities previously deemed uneconomic to recover. At modern mines, the financial viability of recovering byproduct critical minerals, which are not the primary target, may be marginal and can ultimately destine them to mine waste. Further, mine waste can be a liability for the mining company or, at legacy mines, the taxpayer because of its effect on the landscape. The U.S. Geological Survey (USGS) has several initiatives to evaluate critical mineral resources in various types of waste. This factsheet highlights studies of mine waste carried out by USGS scientists at the Geology, Energy & Minerals Science Center in collaboration with other science centers funded through the USGS Mineral Resources Program. Recovery of critical minerals from mine waste can aid in remediation efforts and increase domestic supply of vital mineral resources.

Spatial patterns and temporal trends in water quality in Idaho’s lower Boise River and its tributaries, 1994–2023

Released May 30, 2025 07:34 EST

2025, Scientific Investigations Report 2025-5033

Austin K. Baldwin, Tyler V. King

The lower Boise River in southwestern Idaho is a vital cultural, economic, and ecological resource, but some of its beneficial uses are impaired by excess algae, sediment, nutrients, and bacteria. In response, a variety of water quality improvement projects and regulations have been implemented in recent decades. A recent study showed that, from water years 2003 to 2021, concentrations of total phosphorus at the mouth of the Boise River near Parma decreased by 60 percent, indicating the success of the improvement projects and progress towards reaching the regulatory target. However, although the progress of the system as a whole towards reaching the total phosphorus target is well documented, quantifying contributions and trends in total phosphorus loading from individual tributaries and upstream mainstem locations is needed. Similarly, tributary contributions and trends of other constituents of concern are unknown or have not been evaluated in a decade. To evaluate the success of past water-quality improvement efforts and help prioritize future investments, this study characterized spatial and seasonal patterns in concentrations and loads of suspended sediment, total phosphorus, orthophosphate, total nitrogen, nitrate plus nitrite, Escherichia coli bacteria, and periphyton chlorophyll a (chl-a) at three mainstem and seven tributary sites of the lower Boise River during water years 2019–2023. For sites and constituents with adequate data, temporal trends over a 15-year and 30-year period were also evaluated.

Recent (in other words, water years 2019–2023) concentrations and loads of suspended sediment and total phosphorus were typically greatest during the irrigation season and often exceeded total maximum daily load targets. However, concentrations and loads of suspended sediment, total phosphorus, and orthophosphate have decreased over the past 15 to 30 years at many sites. In contrast, concentrations of total nitrogen and nitrate plus nitrite showed increasing trends at the Boise River near Parma, likely reflecting the effects of regional changes in agricultural practices in recent decades. Periphyton chl-a concentrations during October–November were highly likely increasing over the 30-year period at Boise River at Eckert, but were uncertain at Middleton and Parma. At Boise River at Middleton, periphyton chl-a concentrations exceeded the total maximum daily load target of 150 milligrams per square meter in 75 percent of samples during water years 2019–2023. Results therefore demonstrate that past watershed improvement efforts have been largely effective at reducing concentrations and loads of suspended sediment, total phosphorus, and orthophosphate in the lower Boise River watershed, but different strategies may be needed to reduce concentrations and loads of total nitrogen, nitrate plus nitrite, Escherichia coli, and periphyton chl-a.

Restoration of Gavia immer (common loon) in Minnesota—2024 annual report

Released May 29, 2025 12:45 EST

2025, Open-File Report 2025-1029

William S. Beatty, Kelly Amoth, Luke J. Fara, Brian R. Gray, Kristin Hall, Steven C. Houdek, Jayden Jech, Kevin P. Kenow, Mike J. Wellik, Steven Yang

In cooperation with the Minnesota Department of Natural Resources, the U.S. Geological Survey monitored 98 common loon (Gavia immer) focal territories and an additional 37 nonfocal territories in 2024 across 53 study lakes in Minnesota. Focal territories were those territories from which study inferences will be made, whereas nonfocal territories were observed to monitor common loon dynamics in territories adjacent to focal territories. In collaboration with lake associations and private citizens, we deployed 44 artificial nesting platforms within 44 treatment territories, and the remaining 54 focal territories were controls. We completed territorial surveys from April 29 to August 9, 2024, to evaluate occupancy, nest success, and chick survival. We attempted to visit each territory once a week. At least one nest attempt was observed in 41 of 54 control territories. Precisely one nest attempt was observed in 30 control territories, two nest attempts (first attempts failed) were observed in 9 control territories, and three nest attempts (first and second attempts failed) were observed in 2 control territories. At least one nest attempt was observed in 33 of 44 treatment territories. Precisely one nest attempt was observed in 25 treatment territories, two nest attempts (first attempts failed) were observed in 7 treatment territories, and three nest attempts (first and second attempts failed) were observed in 1 treatment territory. In treatment territories, 8 nests were on an artificial nesting platform; the remaining nest locations were natural. Chicks or other evidence of hatching were observed in 26 of 54 (48.1 percent) control territories and 21 of 44 (47.7 percent) treatment territories, with 7 of those successful treatment nests on an artificial nesting platform. This report includes no formal analysis, but we plan to analyze data after collection of all field data in subsequent years.

Photographic guide to the leaf litter arthropod community of the lowland wet forest ecosystem of the Island of Hawaiʻi

Released May 29, 2025 10:09 EST

2025, Hawaii Cooperative Studies Unit Technical Report HCSU-116

Trebor Hall, Robert W. Peck, Anuhea Robins, Maya Munstermann, Rebecca Ostertag, Esther Sebastian Gonzalez, Nicole DiManno, Susan Cordell, Paul C. Banko

Leaf litter arthropods are important components of the food web in forests, and their presence and diversity can provide information on forest health. There has been very little documentation of the leaf litter arthropods in Hawaiian forest ecosystems. This technical report is a photographic guide to some common arthropods collected from forest leaf litter at the Liko Nā Pilina Hybrid Ecosystems Project study site, a lowland wet forest in Hilo, Island of Hawaiʻi, USA. Leaf litter samples were collected from plots of invaded and experimental restoration communities using two complementary methods (litterbags and quadrats), and arthropods were extracted using Berlese funnels. The field site contained many morphospecies that were rare and locally distributed across plots, and only a few that were very common and widely distributed. The majority of the morphospecies identified were mites. This photoguide is designed to help identify arthropods found in plant litter in Hawaiian lowland forests and it may assist with research and education efforts concerned with the diversity, ecology, or conservation of litter arthropods across the Hawaiian archipelago and other Pacific islands.

Hydrogeologic mapping and three-dimensional geologic modeling of glacial deposits in a multicounty area of southeastern Michigan, northeastern Indiana, and northwestern Ohio

Released May 29, 2025 09:30 EST

2025, Scientific Investigations Report 2025-5008

Alexander D. Riddle, Leslie D. Arihood, Shawn Naylor, David C. Lampe

The glacial deposits underlying southeastern Michigan, northeastern Indiana, and northwestern Ohio are a substantial source of water to communities, agriculture, and industry in the region. Previous efforts to characterize aquifer materials in the area cited a need for additional information about the underlying hydrogeologic characteristics and related groundwater availability as well as improved mapping of the extent and properties of the glacial deposits.

Recent U.S. Geological Survey multi-State compilations of water-well drilling records have greatly increased access to high-resolution geologic data, particularly in glacial depositional environments. This study by the U.S. Geological Survey, in cooperation with the Ohio Environmental Protection Agency, uses processed data from the State-managed collections of well records to characterize the glacial deposits in the study area using two methods. The first method creates two-dimensional maps of basic hydrogeologic information commonly required for assessments of groundwater availability, including (1) total thickness of glacial deposits, (2) total thickness of coarse-grained deposits, (3) specific-capacity-based transmissivity and hydraulic conductivity, and (4) texture-based estimated equivalent horizontal and vertical hydraulic conductivity and transmissivity. The second method builds a hydrogeologic framework of the complex glacial aquifer through construction of a volumetric geologic model by using three-dimensional kriging.

Results of the volumetric model indicate that aquifer materials are primarily concentrated in the western parts of the study area near the Indiana-Ohio border. Coarse-grained sediments are also present as surficial deposits in the north of the study area where intermixing glacial advances created complex distributions of unconsolidated deposits. Two-dimensional maps of hydrogeologic properties support the volumetric model, showing thicknesses of coarse-grained deposits that reach up to 250 feet in the western sections of the study area and progressively thin to near absence in the east. Visualization of the aquifer materials with a volumetric model generally shows a highly discontinuous distribution of coarse- and fine-grained materials, with no clearly defined boundaries to delineate the extent of the aquifer. Comparisons of cross sections derived from the volumetric model with existing published maps support previous near-surface hydrogeologic interpretations while filling gaps where data are sparse, particularly in deeper parts of the aquifer. Both the two-dimensional maps and the volumetric model provide data that can directly inform assessments of groundwater availability, in addition to having future applications to studies of groundwater flow and transport.

Magmatic volatiles in the Yellowstone Plateau volcanic field: The knowns, the unknowns, and the uncertainties

Released May 29, 2025 09:03 EST

2025, Conference Paper, Proceedings of the 3rd IAGC international conference: Water rock interaction-18 & applied isotope geochemistry-15

Shaul Hurwitz, Jacob B. Lowenstern

The Yellowstone Plateau volcanic field has a large magmatic system supplying heat and mass into the overlying hydrothermal system. To interpret changes in the composition and/or emission rates of hydrothermal fluids as possible indicators of volcanic unrest requires discriminating between magmatic, crustal, hydrothermal, and hybrid sources and processes. Significant progress in characterizing the composition and rates of hydrothermal fluid discharge has been made over the past two decades but many uncertainties about sources and processes remain.

Pysochron: A Python-based solution for calculating cosmogenic 26Al/10Be isochron burial ages

Released May 29, 2025 08:06 EST

2025, Quaternary Geochronology (89)

William Elijah Odom

Cosmogenic 26Al/10Be isochron burial dating is a powerful tool for dating sediment burial over the past several million years. By measuring in-situ 26Al and 10Be in a suite of samples from the same depth in a buried deposit, it is possible to quantify the inventory of cosmogenic nuclides produced after burial, date the burial of shallow sediments, identify sediment reworking, and calculate paleo-erosion rates. While this approach has been used to date materials around the world for over a decade, few published codes exist for performing 26Al/10Be isochron calculations. The isochron calculation options that are available typically rely on numerous files and libraries, rendering modification and troubleshooting difficult. Moreover, the widespread use of proprietary programming languages – and their associated addon packages – can place an additional financial burden on an already costly endeavor.

Pysochron (https://code.usgs.gov/recon/pysochron) provides a solution to these issues. In its base form, it exists as a single script that can be easily modified, upgraded, and shared. Because it was developed in an open-source environment, all required computational packages are available free of charge. A user-friendly interface allows rapid modification of calculation parameters, and an automated commentary on isochron results provides insights and recommendations. Pysochron has been validated with 40 published cosmogenic 26Al/10Be burial isochrons around the world, with burial ages ranging from ∼5 Ma to ∼180 ka. As such, it is a promising option for members of the cosmogenic nuclide community seeking a straightforward, cost-effective, and flexible solution to isochron burial dating challenges.

Estimating the magnitude and frequency of floods at ungaged locations on streams in Tennessee through the 2013 water year

Released May 29, 2025 08:00 EST

2025, Scientific Investigations Report 2024-5130

David Ladd, Paul A. Ensminger

To improve estimates of the frequency of annual peak flows for ungaged locations on non-urban, unregulated streams in Tennessee, generalized least-squares multiple linear-regression techniques were used to relate annual peak flows from streamgages operated by the U.S. Geological Survey to physical, climatic, and land-use characteristics of their drainage basins. Geospatial data acquired since the previous study in 2003, annual peak-streamflow data through the 2013 water year, and Bulletin 17C methods for frequency analysis of annual peak-streamflow data were used in the study. Generalized least-squares regression equations were developed for four hydrologic areas with distinct hydrologic, geologic, and topographic characteristics. Drainage area was used as an explanatory variable in equations developed for each hydrologic area. In addition to drainage area, a 2-year recurrence-interval climate factor was used for hydrologic area 1, a 10–85 channel slope was used for hydrologic area 2, and percent imperviousness was used for hydrologic area 4. The regression equations can be used to estimate annual exceedance probability streamflows for ungaged locations on non-urban, unregulated streams in Tennessee. The term “unregulated” indicates that streamflow is not appreciably influenced by regulation from reservoirs or other impoundments. Average standard errors of prediction for the regression equations ranged from 44.4 to 51.4 percent for hydrologic area 1; 30.4 to 42.9 percent for hydrologic area 2; 35.7 to 42.6 percent for hydrologic area 3; and 32.5 to 47.4 percent for hydrologic area 4.

On the importance and practical conservation of nongame fishes.

Released May 28, 2025 10:20 EST

2025, Fisheries

Niall G. Clancy, Frank J. Rahel, Brandon K. Peoples, Annika W. Walters, John Lyons, Nicholas E. Mandrak, Phaedra E. Budy, Emmanuel A Frimpong, Wyatt F. Cross

Fisheries management has historically focused conservation efforts on game or sport species. However, most species are nongame—those not traditionally captured for sport or harvest in countries where recreational fisheries predominate. Greater conservation of nongame species could help ensure that population declines do not go unnoticed. Unfortunately, fisheries managers already manage complex ecosystems with limited resources, and they frequently are directed to focus on game fishes. However, game fish populations can also be tightly coupled to nongame fishes, so nongame management can sometimes also benefit game species. We reviewed functional roles of freshwater nongame fishes and suggest categories that may be especially important for conservation. Of note, nongame fishes are more imperiled than game fishes and fill largely distinct functional roles. These roles include food-web impacts, ecosystem engineering, and mussel hosting. Management priorities could include nongame piscivores and species with high biomass, especially herbivores, nest builders, and imperiled mussel hosts. We provide practical options for including nongame fishes in current management, many of which require little additional funding. These include recognizing when sport fish funding and conservation can also benefit nongame species, whole-community sampling at some monitoring locations, collecting catch data for select species observed during game fish surveys, embracing environmental DNA sampling, and making presence–absence record keeping the default option.

Distribution, abundance, and breeding activities of Southwestern Willow Flycatchers (Empidonax traillii extimus) at select locations on the San Luis Rey River, San Diego County, California—2024 data summary

Released May 28, 2025 07:34 EST

2025, Data Report 1212

Scarlett L. Howell, Barbara E. Kus

We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) at select locations along the San Luis Rey River, including along the middle San Luis Rey River near Bonsall and the upper San Luis Rey River near Santa Ysabel, California, in 2024. Surveys were completed at six locations: two along the middle San Luis Rey River (Bonsall [BO] and Rincon), which were last surveyed in 2021, and four along the upper San Luis Rey River, including three downstream from Lake Henshaw that have been surveyed annually since 2015 (Rey River Ranch, Cleveland National Forest [CNF], Vista Irrigation District [VID]), and one upstream at VID Lake Henshaw (VLH) that has been surveyed annually since 2018. There were a minimum of 47 territorial flycatchers (26 male, 21 female) detected at 1 location (VLH) and 6 transient flycatchers of unknown subspecies detected at 3 locations (BO, CNF, and VLH). In total, 30 territories were established, containing 21 pairs and 9 flycatchers of undetermined breeding status. Of the 21 pairs, 13 pairs were monogamous (1 male and 1 female), and 8 pairs were polygynous (1 male paired with more than 1 female). No territorial flycatchers were detected downstream from Lake Henshaw or along the middle San Luis Rey River. Brown-headed Cowbirds (Molothrus ater; cowbird) were detected at all six survey locations. No banded flycatchers were detected during surveys.

Flycatchers used four habitat types in the survey area: (1) mixed willow riparian, (2) willow-cottonwood, (3) willow-oak, and (4) willow-sycamore. Of the flycatcher locations, 86 percent were in habitat characterized as mixed willow riparian, and 97 percent were in habitat with greater than 95-percent native plant cover.

We monitored flycatcher nests at VLH to collect baseline data on nest success, productivity, and parasitism rate. There were 22 nests monitored in 13 territories; 9 were successful. Of the 13 failed nests, 8 were depredated, 3 failed for unknown reasons, and 2 failed because of cowbird parasitism. We confirmed 26 juvenile flycatchers in 2024, which included 22 from monitored nests, and an additional 4 juveniles detected in unmonitored territories. Based on 19 nests in which the contents were observed during the egg stage, 16 percent of nests in 2024 were parasitized.

2023 Earthquake Ground-Motion Workshop for the Central and Eastern United States, with a focus on the Gulf and Atlantic Coastal Plains—Agenda and abstracts

Released May 27, 2025 17:30 EST

2025, Scientific Investigations Report 2025-5025

Oliver S. Boyd, Julie A. Herrick, Ashly Cabas, Sean K. Ahdi

The U.S. Geological Survey held a virtual workshop December 7–8, 2023, to share research and ideas about earthquake ground motions in the Central and Eastern United States, with a focus on the Atlantic and Gulf Coastal Plains. The workshop was organized to learn about potential regionalization of ground-motion characteristics (source, path, and site), consider new explanatory variables for site response, and hear and discuss updates on ground-motion research on the Atlantic and Gulf Coastal Plains. The workshop was organized into a series of contributed presentations and three panel discussions held during 2 days. This report documents the agenda, contributed abstracts, and panel summaries.

The 3D Elevation Program—Supporting Connecticut's economy

Released May 27, 2025 12:20 EST

2025, Fact Sheet 2025-3030

Laura Harrington, Dan Walters

Introduction 

Connecticut has a diverse, largely forested landscape characterized by hills and low mountains in the Western Upland, hills in the Eastern Upland, ridges and broad valleys in the Central Lowland, and many beaches and harbors along the coast of Long Island Sound. Connecticut is manufacturing and service focused, ranking almost highest among the 50 States in the United States in personal income per capita. Due to Connecticut’s dense population, many people, especially the approximately 60 percent living near the coast, may be affected by climate-driven disasters. High-quality elevation data can inform the activities of many nongovernmental organizations and municipal and academic entities statewide, resulting in substantial economic impact. Government at the State and local levels relies on these data to support regulatory permitting, resource and infrastructure management, and various engineering and planning-level analyses. Critical applications that meet the State’s management needs depend on light detection and ranging (lidar) data that provide a highly detailed three-dimensional (3D) model of the Earth’s surface and aboveground features.

The 3D Elevation Program (3DEP) is managed by the U.S. Geological Survey in partnership with Federal, State, Tribal, U.S. territorial, and local agencies to acquire consistent lidar coverage at quality level 2 or better to meet the many needs of the Nation and Connecticut. The status of available and in-progress 3DEP baseline lidar data in Connecticut is shown. 3DEP baseline lidar data include quality level 2 or better, 1-meter or better digital elevation models, and lidar point clouds, and must meet the Lidar Base Specification version 1.2 or newer requirements. The National Enhanced Elevation Assessment identified user requirements and conservatively estimated that availability of lidar data would result in at least $4.40 million in new benefits annually to the State. The top 10 Connecticut business uses for 3D elevation data, which are based on the estimated annual conservative benefits of 3DEP, are shown.

Coexistence beyond disciplinary silos: Five dimensions of analysis for more convivial human-predator interactions

Released May 27, 2025 09:03 EST

2025, Biological Conservation (308)

Judith E. Krauss, Valentina Fiasco, Silvio Marchini, Michael McInturff, Laila T. Sandroni, Peter S. Alagona, Dan Brockington, Bram Büscher, Rosaleen Duffy, Katia Maria P.M. de Barros Ferraz, Rob Fletcher, Wilhelm Andrew Kiwango, Sanna Komi, Mathew Bukhi Mabele, Kate Massarella, Anja Nygren

Understanding human-predator interactions has been a central goal of conservation for decades, yet many previous efforts have approached this challenge from disciplinary perspectives focused on single case studies. There is a need for more transdisciplinary and multi-sited research to enrich our understandings of the complexity of human-nonhuman interactions and to design ways to make them more convivial. The multi-year CONVIVA “convivial conservation” research project addressed this gap, involving scholars from natural sciences, social sciences and humanities to promote coexistence, biodiversity and justice in conservation across four diverse case studies of apex predators: jaguars in Brazil, wolves in Finland, lions in Tanzania, and brown bears in California, United States. In this article, we set out two key contributions. First, we highlight how our project created iterative, dialogue-based reflections amongst different disciplines and perspectives to inform research questions, methods and units of analysis, fulfilling what we see as a key need in the literature. Second, we operationalise our collaboration beyond disciplinary silos into a novel framework of five interconnected dimensions of analysis, that characterise human-predator interactions, drawing on a range of lenses and including a series of guiding questions. We also showcase empirical material from our cases across wildlife, environment, interactions, institutions and justice dimensions. We present our approach, framework and findings with collective reflections and an invitation for adaptation and further research on their suitability to other contexts and species.

Combining acoustic telemetry and side-scan sonar to estimate abundance of endangered shortnose sturgeon in the Hudson River, New York

Released May 26, 2025 09:53 EST

2025, Canadian Journal of Fisheries and Aquatic Sciences

Amanda Higgs, Shannon L. White, John Madsen, David C. Kazyak, Dewayne Fox, Richard Pendleton, Adam Bonemery, Tomasz Smolinski, Amanda Simmonds, Patrick Sullivan

For endangered shortnose sturgeon (Acipenser brevirostrum), the ability to estimate and monitor population size is critical for tracking species’ recovery. Yet, contemporary abundance estimates have not been completed for many shortnose sturgeon populations, largely owing to the difficulty in using traditional abundance estimators for sturgeons. Here, we estimate the adult shortnose sturgeon population size of the Hudson River, NY by integrating data from two largely passive sampling methods – acoustic telemetry and side-scan sonar – into a Bayesian hierarchical model of abundance. We estimated the adult abundance to be 69,798 individuals (95% CI = 9,207-185,666), making the Hudson River the largest extant shortnose sturgeon population. Despite this, the population remains vulnerable to localized disturbances, as over 40% of the population congregated in a small overwintering habitat that coincides with an area of high anthropogenic activity. Accordingly, recurrent demographic surveys may be beneficial for gaining insight into the relative effects of anthropogenic and naturally stochastic processes shaping shortnose sturgeon demography. Our modeling framework provides a relatively low-cost alternative for future demographic monitoring of species of conservation concern.

Visioning and conceptual framework for coordinating Great Lakes connecting waters research and monitoring

Released May 26, 2025 09:34 EST

2025, Journal of Great Lakes Research

Robin L. DeBruyne, Edward F. Roseman, Ashley H. Moerke, Lauren M Fry, Michael R. Twiss, Samantha N. Tank

The Laurentian Great Lakes are connected via naturally occurring straits and rivers: St. Marys River, Straits of Mackinac, St. Clair-Detroit River System, Niagara River, and the St. Lawrence River. Despite the historical ecological and economic importance of these waters, international agreements (e.g., Great Lakes Water Quality Agreement) only recently explicitly named the Great Lakes Connecting Waters (GLCWs), requiring governments to address the challenges of adequate restoration and protection from historical use and degradation. Standardized research and monitoring activities are needed; however, there is no established mechanism for coordination across the GLCWs. A three-day summit in 2023 convened experts to form the initial framework for a GLCWs Collaborative to increase standardizations and knowledge transfer. Participants drafted a governance structure and priorities following the principles of collective impact but allowed for place-based specificity for local connecting water organizations. Priorities and suggestions for success included: 1) co-development of the collaborative with all rights holders, stakeholders, and surrounding communities; 2) investment in research and technology specific to GLCWs; 3) investment in information transfer and training; 4) increased communication; and 5) better integration into existing Great Lakes research, monitoring, and funding programs. Expanding participation in all local GLCWs organizations with principles of inclusivity was identified as a larger collaborative goal. Next steps in the development of a GLCWs Collaborative include increased communication and formation of working groups and obtaining funding for a dedicated organization to begin supporting activities (communication, facilitation, logistics). By using a deliberate process for establishment, the potentially slower time frame for establishment may result in increased participation and success.

Mobile radar provides insights into hydrologic responses in burn areas

Released May 26, 2025 09:21 EST

2025, International Journal of Wildland Fire (34)

Jonathan J. Gourley, Yagmur Derin, Pierre-Emmanuel Kirstetter, John Fulton, Laura A. Hempel, Braden White

Background

Wildfires often occur in mountainous terrain, regions that pose substantial challenges to operational meteorological and hydrologic observing networks.

Aims

A mobile, post-fire hydrometeorological observatory comprising remote-sensing and in situ instrumentation was developed and deployed in a burnt area to provide unique insights into rainfall-induced post-fire hazards.

Methods

Mobile radar-based rainfall estimates were produced throughout the burn area at 75-m resolution and compared with rain gauge accumulations and basin response variables.

Key results

The mobile radar was capable of resolving details in intra-basin rain fields as well as detecting storms approaching the burn area with accuracy equivalent to rain gauges. Runoff responses were complex and dependent on spatiotemporal patterns and magnitude of rainfall intensity over the burn area.

Conclusions

The complement of the mobile radar with the near-field, non-contact instruments measuring the hydrologic response provided valuable information in regions that are difficult to access and are not routinely monitored by conventional observing networks.

Implications

Post-fire observatories equipped with mobile radars deployed on burn areas provide real-time data, early alerting capabilities and visualizations to potentially guide impact-based decision support for local authorities.

The perspective of youth: Envisioning transformative pathways and desirable futures for people and nature

Released May 26, 2025 08:14 EST

2025, Sustainability Science

Thomas M. Schmitt, Juliette Aminian–Biquet, Polina Blinova, Yohana G. Jimenez, Lider Sinav, Hana Vašková, Ana Sofia Lorda Dumont, Pham Trung Kien, Vinamra Mathur, Brenda Mwale, Deign Frolley Soriano, Nopparat Anantaprayoon, Abdul Wahid Arimiyaw, Sheila Koech, Kantuta Conde Choque, HyeJin Kim, Jan J. Kuiper, Laura M. Pereira, Brian W. Miller

This paper examines the pathways to desirable nature futures as envisioned by 22 young people from all United Nations regions and diverse cultural backgrounds who participated in the second edition of the IPBES Youth workshop (2022). The workshop employed the Three Horizons framework and the Nature Futures Framework (NFF) to describe the plurality of youth visions for desirable nature futures and transformative pathways to achieve these visions. Based on the outcomes of the workshop, we conducted a qualitative content analysis categorizing the ideas and quantitatively assessed commonalities and differences among workshop groups, which were based on the NFF perspectives (nature for nature, nature for society, nature as culture, and a group in between perspectives). There were important differences in the visions and pathways articulated by the groups, but also commonalities, such as the importance of governance, community-based approaches, and education for achieving desirable nature futures. We also discuss the importance of flexibility in the NFF to accommodate diverse perspectives and involvement of youth in shaping global sustainability agendas. While many ideas raised by young people during this workshop align with existing conservation narratives, the study reveals the need to foster new and innovative ideas to drive transformative change that is sensitive to diverse contexts, histories, and experiences.

Insights from megacryst-included zircon dates on the spatial extent of magma mixing in the Tuolumne Intrusive Suite, California, USA

Released May 24, 2025 09:41 EST

2025, Geochemistry, Geophysics, Geosystems (26)

Elena Watts, Julia Ye, Sean Patrick Gaynor, Valbone Memeti, Blair Schoene

The spatial extent of mixing between separately emplaced batches of magma is a key component in understanding the incremental assembly of plutons. Potassium feldspar megacrysts (>3 cm length) in granodioritic rocks are hypothesized to record magma mixing and transport over hundred kyr timescales. CA-ID-TIMS U-Pb dates from zircon inclusions within 11 new megacryst samples and their surrounding matrix from the Tuolumne Intrusive Suite are presented as a means of evaluating the extent of mixing across a less than two km wide gradational contact. Megacrysts from within the gradational contact yielded zircon dates consistent with mixing or transport from the older porphyritic Half Dome Granodiorite, but the zircon included in megacrysts from the younger Cathedral Peak Granodiorite show no evidence of interaction with the porphyritic Half Dome. These results, along with the trace element geochemistry of the zircon, suggest that the porphyritic Half Dome and Cathedral Peak magmas where we sampled were not comagmatic, which constrains the width of a mixing front to the kilometer scale gradational contact between these units. From within this gradational contact, we do find evidence of mixing consistent with prior studies. Differences between the core- and rim-included zircon date spectra also suggest that protracted growth is recorded in some K-feldspar megacrysts but may not be a requirement for forming them.

Ecological scenarios: Embracing ecological uncertainty in an era of global change

Released May 24, 2025 08:26 EST

2025, Ecosphere (16)

Kyra Clark-Wolf, Wynne Emily Moss, Brian W. Miller, Imtiaz Rangwala, Helen Sofaer, Gregor W. Schuurman, Dawn Magness, Amy Symstad, Jonathan Coop, Dominique M. Bachelet, Joseph Barsugli, A. Ciocco, Shelley D. Crausbay, Tyler Hoecker, Jena Lewinsohn, Meagan Ford Oldfather, Orien Richmond, Renee Rondeau, A. Runyon, Robin Russell, Jennifer L. Wilkening

Scenarios, or plausible characterizations of the future, can help natural resource stewards plan and act under uncertainty. Current methods for developing scenarios for climate change adaptation planning are often focused on exploring uncertainties in future climate, but new approaches are needed to better represent uncertainties in ecological responses. Scenarios that characterize how ecological changes may unfold in response to climate and describe divergent and surprising ecological outcomes can help natural resource stewards recognize signs of nascent ecological transformation and identify opportunities to intervene. Here, we offer principles and approaches for more fully integrating ecological uncertainties into the development of future scenarios. We provide examples of how specific qualitative and quantitative methods can be used to explore variation in ecological responses to a given climate future. We further highlight opportunities for ecological researchers to generate actionable projections that capture uncertainty in both climatic and ecological change in meaningful and manageable ways to support climate change adaptation decision making.

Reliability of satellite-based vegetation maps for planning wildfire-fuel treatments in shrub steppe: Inferences from two contrasting national parks

Released May 24, 2025 07:58 EST

2025, Journal of Environmental Management (387)

Samuel J. Price, Chad Raymond Kluender, Matthew J. Germino, Thomas Rodhouse

Protecting habitat threatened by increasing wildfire size and frequency requires identifying the spatial intersection of wildfire behavior and ecological conditions that favor positive management outcomes. In the perennial sagebrush steppe of Western North America, invasions by fire-prone annual grasses are a key concern, and management of them requires reliable maps of vegetation cover, fuels, and wildfire behavior. We compared commonly used, publicly available vegetation cover and fuels maps, specifically the Rangeland Analysis Platform (RAP) and LANDFIRE, with field-based assessments at two U.S. National Parks dominated by sagebrush steppe: City of Rocks National Reserve and Craters of the Moon National Monument and Preserve. Plant-community composition and fuels measured at ∼1700 field locations spanning ∼300,000 ha revealed that 1) RAP generally underestimated each vegetation cover type where the cover was actually abundant, and conversely overestimated cover types where they were actually scarce, and 2) there was considerable disagreement in fuel-bed maps derived from LANDFIRE compared to field observations. As a result, there were substantial discrepancies in the spatial patterning of wildfire behavior estimated from the fire-spread model FLAMMAP when parameterized with LANDFIRE compared to field-based fuel-bed maps created from Random Forests models. Reliable maps of vegetation cover and fuel conditions are needed to help guide fuels and invasive species management, especially given recent increases in pre- and post-fire treatments in arid and semiarid landscapes. The costs associated with poorly informed fuel reduction may greatly exceed the costs of field-based vegetation and fuels inventory to inform effective design of vegetative fuels treatments.

Using subducting plate motion to constrain Cascadia slab geometry and interface strength

Released May 23, 2025 09:17 EST

2025, Geochemistry, Geophysics, Geosystems (26)

Menno Fraters, Magali Billen, John Naliboff, Lydia M. Staisch, Janet Watt, Haoyuan Li

Subduction zones are home to multiple geohazards driven by the evolution of the regional tectonics, including earthquakes, volcanic eruptions and landslides. Past evolution builds the present-day structure of the margin, while the present-day configuration of the system determines the state-of-stress in which individual hazardous events manifest. Regional simulations of subduction zones provide a tool to synthesize the tectonic history of a region and investigate how geologic features lead to variations in the state of stress across the subduction system. However, it is challenging to design regional models that provide a force-balance that is consistent with the large-scale motion of surrounding tectonic plates while also not over-constraining the solution. Here, we present new models for the Cascadia subduction zone that meet these criteria and demonstrate how the motion of the subducting Juan de Fuca plate can be used to determine the along-strike variations in the viscous (long-term) coupling across the plate boundary. All successful models require lower viscous coupling in the northern section of the trench compared to the central and southern sections. However, due to uncertainties in the geometry of the Cascadia slab, we find that there is a trade-off between along-strike variation in viscous coupling and slab shape. Better constraints on the slab shape, and/or use of other observations are needed to resolve this trade-off. The approach presented here provides a framework for further exploring how geologic features in the overriding plate and the properties of the plate boundary region affect the state-of-stress across this and other subduction zones.

Modeling individual-level and population-level nest success of California Condors from movement data

Released May 23, 2025 08:44 EST

2025, Journal of Raptor Research (59)

Andrea Blackburn, Joseph Michael Eisaguirre, Joseph C. Brandt, Arianna Punzalan, Laura McMahon, Molly Astell, Nadya E. Seal Faith, David J. Meyer, Estelle A. Sandhaus

The California Condor (Gymnogyps californianus) is a critically endangered species with populations that are not currently self-sustaining. Although understanding nest success is key to understanding trends in their populations, field monitoring of condor nests has become increasingly challenging as the number of nesting condors has increased and their range has expanded. We investigated whether California Condor nest fate could be accurately estimated from telemetry data with limited field observations. Our study focused on the southern California population of California Condors (2015–2022), and we used a recently published Bayesian hierarchical modeling framework that combines movement data and occasional field observations to estimate individual-level and population-level nest success. The model detected shifts in space use to categorize if each nest failed or if a young fledged. Estimated model parameters suggested that after nest failure, condors shifted toward more expansive space use. Additional field observations, not included as data in the model, provided evidence that we accurately categorized nest fate for 63 out of 65 California Condor nesting attempts. Finally, we scaled individual-level reproductive success to estimate annual population-level nesting success. These methods offer managers a way to reduce field monitoring efforts while still allowing for estimation of nest success, which will be key as the breeding populations of California Condors continue to grow and become more widely spread across the landscape.

Optimizing the effectiveness of connectivity modifiers to reduce dryland degradation

Released May 23, 2025 08:05 EST

2025, Restoration Ecology

Kristina E. Young, Brandon L. Edwards, Michael C. Duniway, Nicholas Webb

Dryland degradation from unsustainable land use and increasing aridity often manifests as bare, interconnected areas that facilitate the loss or redistribution of resources (soil, seeds, and nutrients) through wind and run-off. Physical structures like branches and stick bundles, which disrupt these pathways and retain resources, are crucial for rehabilitation and restoration. Connectivity modifiers or ConMods, which are galvanized mesh structures that mimic low stature vegetation, are tools specifically designed to interrupt connected pathways and help reinforce overall site stability. Yet, how to effectively and consistently use ConMods to achieve site stability has not been thoroughly tested. Here, we used the Aeolian EROsion model to investigate the combined effects of ConMod height, porosity, and spacing on simulated horizontal sediment flux, a key indicator of site stability. We assessed ConMod performance as percent reduction in predicted sediment flux versus a bare, unvegetated 10,000 m2 area for a range of horizontal sediment flux. Additionally, in a field experiment, ConMods increased litter retention by up to 15.6 mm compared to bare ground plots, demonstrating their potential to enhance both soil stabilization and resource retention. These findings underscore the potential of ConMods as flexible, cost-effective tools that interrupt positive feedbacks to degradation and provide measurable benchmarks for restoration success.

Cooperative Fish and Wildlife Research Units Program—2023 Year-in-Review

Released May 22, 2025 16:25 EST

2025, Circular 1545

Elise R. Irwin, Caroline Murphy, Dawn E. Childs, Donald E. Dennerline, Jonathan R. Mawdsley

Introduction 

Established in 1935, the U.S. Geological Survey (USGS) Cooperative Fish and Wildlife Research Units Program is a unique cooperative partnership among State fish and wildlife agencies, host universities, the Wildlife Management Institute, USGS, and the U.S. Fish and Wildlife Service. Designed to meet the scientific needs of natural resource management agencies and to produce trained wildlife management professionals, the program has grown from the original nine wildlife-only Units to a program that, as of 2024, includes 43 Units located on university campuses in 41 States.

Using high-resolution geospatial imagery and data to document the evolution of the Wilderness Breach that was created by Hurricane Sandy in 2012 at Fire Island National Seashore, New York

Released May 22, 2025 13:55 EST

2025, Open-File Report 2025-1020

Gary B. Fisher

The U.S. Geological Survey’s National Civil Applications Center obtained remote sensing data and imagery collected from 1939 through 2023 to monitor changes at Fire Island National Seashore, New York. On October 29, 2012, an inlet was created during Hurricane Sandy on Fire Island that remained open for 10 years. This inlet, named the “Wilderness Breach,” formed at the same location where an inlet had previously existed and remained open from 1763 to 1825. This report documents the morphological changes that occurred at the Wilderness Breach during the 10-year existence of this feature.

Effects of nonmotorized recreation on ungulates in the western United States—A science synthesis to inform National Environmental Policy Act analyses

Released May 22, 2025 13:20 EST

2025, Scientific Investigations Report 2025-5014

Samuel E. Jordan, Taylor R. Ganz, Tait K. Rutherford, Matthew J. Blocker, Christopher T. Domschke, Frederick L. Klasner, Elroy H. Masters, Tye A. Morgan, Daryl R. Ratajczak, Elisabeth C. Teige, Sarah K. Carter

The U.S. Geological Survey is working with Federal land management agencies to develop a series of science syntheses to support National Environmental Policy Act (NEPA) analyses. This report synthesizes science information about the potential effects of nonmotorized recreation on ungulates in the western United States. We conducted a structured literature search to find published science, data, and analysis methods about the characteristics of nonmotorized recreation, ungulate exposure and response to nonmotorized recreation, and approaches to mitigate negative effects of nonmotorized recreation on ungulates. The sections of the report align with standard elements of the NEPA analysis process. We found that timing, intensity, duration, and spatial distribution of nonmotorized recreation are important factors to understand when assessing effects of recreation on ungulates. Several aspects of ungulate biology, which vary by species, population, and individual, affect ungulate susceptibility to effects from recreation, including diet, migration and movement, and seasonal biology. Techniques for assessing effects include basic spatial analyses based on buffers around trails and recreation sites and more technical analytical methods based on displacement or avoidance of recreation sites. Options for mitigating negative effects of nonmotorized recreation on ungulates include timing and type-of-use restrictions, recreator education, and project design features to avoid human-ungulate conflicts. Public land managers can use this report by incorporating it by reference in NEPA analyses or as a general reference to find literature or identify gaps in the literature about the effects of noise from nonmotorized recreation on ungulates.

The Volcano letter: A weekly news leaflet of the Hawaiian Volcano Research Association - 1925

Released May 22, 2025 11:48 EST

1925, Report

The Volcano Letter was an informal publication issued at irregular intervals by the Hawaiian Volcano Observatory (HVO) during the years 1925 to 1955. Individual issues contain information on volcanic activity, volcano research, and volcano monitoring in Hawaii. Information on volcanic activity at other locations is also occasionally included.

The Volcano Letter was published by HVO through multiple changes in administration, including the Hawaiian Volcano Research Association (1925 to 1932), the U.S. Geological Survey (1932 to 1935), the Department of the Interior (1935 to 1938), and the University of Hawai‘i (1938 to 1955). Issues 1-262 were published weekly from January 1, 1925, to January 2, 1930, and consisted of a single page of text. Issues 263-384, also published weekly, from January 9, 1930, to May 5, 1932, were generally longer—four pages— and provided more detail on volcanic activity, including photographs, maps, and plots. Weekly issues 385-387, published May 12-26, 1932, were a single page of text due to budget reductions brought on by the Great Depression. Budget restrictions reduced the publishing frequency to monthly for issues 388-428, covering the period of June 1932 to October 1935; these issues were generally shorter, 1-2 pages, and sometimes featured figures. From November 1935 to July 1938, issues 429-461 remained monthly but increased in length (generally eight pages) and featured figures frequently. Issues 462-530, published over the period of August 1938 to December 1955, varied in length from 2-15 pages, but were published quarterly, rather than monthly.

Six of the Volcano Letters are misnumbered:
Jan. 21, 1926 number is 55 though it should 56
July 29, 1926 number is 82 though it should be 83
Feb. 16, 1928 number is 161 though it should be 164
May 31, 1928 number is 197 though it should be 179
Nov. 29, 1928 number is 204 though it should be 205

Monitoring visitor activity and informal trail disturbance in Yosemite Valley meadows to assess temporal changes in use and impacts

Released May 22, 2025 08:47 EST

2025, Journal of Outdoor Recreation and Tourism (50)

Sheri A. Shiflett, Jeffery S. Jenkins, Rachel F. Mattos, Kai Thiry, Peter Christian Ibsen, Melissa Booher, Angela Tricomi, Nicole D. Athearn

Montane meadows provide vital habitat that supports ecosystems, regulate hydrological processes, and offer valuable recreational opportunities. Meadows account for 3 % of Yosemite National Park's area, including Yosemite Valley, and are particularly susceptible to human impacts such as formation of informal trails. We collected observational data on visitor activity and quantified social trail disturbance to compare with resource monitoring datasets and through similar parameters to Walden-Schreiner and Leung (2013) who studied visitor use and behavior in three Yosemite Valley meadows in 2011. We documented change in number of visitors per hour and primary activity pursued. We also compared trends of meadow disturbance (informal trail length and disturbed area) from the early 2000s - 2023. Informal trail length at El Capitan Meadow decreased from 2004 to 2018, followed by recent increases. Disturbed area for Cooks A, Sentinel A, Slaughterhouse B, Stoneman A, and Stoneman B sub-meadows increased from 2006 to 2023. Between 2011 and 2023, the proportion of those engaged in active versus stationary pursuits showed that visitors engaged in more active pursuits in two of three meadows. Moreover, there were >3.5 times more visitors per hour in Cooks, El Capitan, and Leidig meadows in 2023 compared to 2011, yet, most visitors utilized designated trails. Meadow locational context was linked to activity preference and types of impacts. Management strategies, such as fencing and signage have been effective at minimizing impacts in several meadows. Parsing nuances of informal trail use and drivers of disturbance for various meadows is crucial for informed park management decisions and actions.

Enhanced geothermal systems electric-resource assessment for the Great Basin, southwestern United States

Released May 22, 2025 08:17 EST

2025, Fact Sheet 2025-3027

Erick R. Burns, Colin F. Williams, Jacob DeAngelo

The U.S. Geological Survey recently (2025) completed a provisional assessment of the geothermal-electric resources associated with high-temperature, low-permeability rock formations of the Great Basin, Southwestern United States. If sufficient technological advances to commercialize enhanced geothermal systems occur, then a current best provisional estimate for electric-power generation capacity of 135 gigawatts electric are available from the upper 6 kilometers of the Earth’s crust. This estimate is a potential substantial increase of the installed geothermal electricity-generating capacity from <1 to 10 percent of current total U.S. power production capacity.

Histological progression and bacterial load dynamics of Renibacterium salmoninarum in Chinook salmon Oncorhynchus tshawytscha

Released May 22, 2025 08:00 EST

2025, Diseases of Aquatic Organisms (162) 85-97

Riley E. Dils, Tawni B.R. Firestone, Paula A. Schaffer, Dana L. Winkelman, Eric R. Fetherman

Renibacterium salmoninarum, the cause of bacterial kidney disease (BKD), severely impacts salmonid populations. Much of our understanding of the BKD pathology in salmonids comes from evaluating fatal infections in wild populations or spawning Pacific Northwest salmonids. Our study investigated the histological progression and bacterial load dynamics of R. salmoninarum infection in Chinook salmon following intraperitoneal injection to enhance understanding of the disease’s dynamics. Seventy presmolt salmon were injected with the ATCC-33209 isolate of R. salmoninarum and monitored over 10 wk. Histological signs of disease were observed in spleen and liver tissues at 1 wk post-injection and in kidney tissues at 4 wk post-injection, with signs of disease increasing over time. Additionally, histopathological analysis revealed splenic and hepatic capsulitis (coelomitis), individual hepatocyte necrosis, progressive granulomatous hepatitis, splenitis, and nephritis with necrosis. Gram staining confirmed the presence of Gram-positive bacteria within macrophages and extracellularly in infected tissues. Quantitative PCR revealed significant increases in bacterial loads in both kidney and liver tissues over the study period, with higher bacterial loads observed in the kidney tissue. Bacterial load was strongly correlated with disease stage, with peak bacterial burdens coinciding with the most severe histological changes. Our study provides a comprehensive account of R. salmoninarum infection and disease progression in Chinook salmon after intraperitoneal injection.

Assessment of conventional and continuous oil and gas resources in the Mowry Composite Total Petroleum System in the Southwestern Wyoming Province, Wyoming, Colorado, and Utah, 2024

Released May 21, 2025 11:45 EST

2025, Fact Sheet 2025-3023

Jane S. Hearon, Christopher J. Schenk, Sarah E. Gelman, Benjamin G. Johnson, Jenny H. Lagesse, Tracey J. Mercier, Heidi M. Leathers-Miller, Kira K. Timm, Ronald M. Drake II, Andrea D. Cicero, Phuong A. Le

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional and continuous resources of 473 million barrels of oil and 27 trillion cubic feet of gas in the Mowry Composite Total Petroleum System in the Southwestern Wyoming Province, Wyoming, Colorado, and Utah.

Bedrock geologic map of the Bellows Falls 7.5- x 15-minute quadrangle, Windham and Windsor Counties, Vermont, and Sullivan and Cheshire Counties, New Hampshire

Released May 21, 2025 10:30 EST

2025, Scientific Investigations Map 3535

Arthur J. Merschat, Gregory J. Walsh, Peter M. Valley, Ryan J. McAleer, Thomas R. Armstrong

Introduction 

The bedrock geology of the Bellows Falls 7.5- x 15-minute quadrangle, Vermont and New Hampshire, consists of polydeformed Ordovician to Devonian metasedimentary, metavolcanic, and metaplutonic rocks of the Connecticut Valley trough, Bronson Hill anticlinorium (or Bronson Hill terrane), and the Central Maine terrane. Previous work in this area includes a 1:62,500-scale published map and text (1946), State geologic maps of New Hampshire (1997) and Vermont (2011), and various maps and reports presented largely as parts of field trip guidebooks. A provisional open-file map of the geology of the Vermont part of the Bellows Falls 7.5- x 15-minute quadrangle, completed in 1997, is incorporated and revised on this map based on additional fieldwork.

This study recognizes three major structural levels from west to east and from lowest to highest: (1) autochthonous rocks of the Connecticut Valley trough; (2) allochthonous rocks of the New Hampshire sequence and Bronson Hill arc in the Monroe thrust sheet (or nappe), including the Skitchewaug nappe; and (3) allochthonous rocks of the Fall Mountain thrust sheet or nappe.

Bayesian ETAS modeling for the Pacific Northwest: Uncovering effects of tectonic regimes, regional differences, and swarms on aftershock parameters

Released May 21, 2025 09:23 EST

2025, Bulletin of the Seismological Society of America

Max Schneider, Michael Barall, Peter Guttorp, Jeanne L. Hardebeck, Andrew J. Michael, Morgan T. Page, Nicholas van der Elst

The Pacific Northwest (PNW) of North America has high seismic hazard due to numerous earthquake sources under populated areas. It hosts several tectonic regimes and subregional seismic zones that are hypothesized to have different patterns of earthquake and aftershock occurrence. It is also predisposed to earthquake swarms, which can complicate the statistical modeling of these patterns. We present the first statistical seismicity model of the PNW catalog using the epidemic‐type aftershock sequence (ETAS) framework. We develop a Bayesian inference procedure that provides a stable estimation of both ETAS parameters and their uncertainties for different sets of PNW earthquakes, even those with very sparse catalogs. The Bayesian approach allows us to investigate how parameter estimates change between the intraslab and crustal tectonic regimes, the northern and southern PNW, and when swarms are included and excluded from the catalog. We also utilize our Bayesian framework to calculate parameter estimates under different prior beliefs about PNW seismicity, as well as to propagate catalog measurement errors into ETAS parameter estimates. We discuss the implications of parameter differences across the region for aftershock forecasting for the PNW.

Linking fire radiative power to land cover, fire history, and environmental setting in Alaska, 2003–2022

Released May 21, 2025 09:06 EST

2025, International Journal of Wildland Fire (34)

Jessica J. Walker, Rachel A. Loehman, Britt Windsor Smith, Christopher E. Soulard

Background

Fire radiative power (FRP) shows promise as a diagnostic and predictive indicator of fire behavior and post-fire effects in Alaska, USA.

Aims

To investigate relationships between FRP, vegetation functional groups, and environmental settings in Alaska (2003–2022) under various fire history conditions.

Methods

We tested for distinctness of MODIS FRP distributions associated with vegetation classes and fire legacies (frequency and number of previous burns). We used a random forest model to examine relative importance of vegetation class for FRP versus bottom-up biophysical and temporal parameters.

Key results

FRP distributions are statistically distinct among vegetation functional groups with contrasting fuel biomass, or within functional groups with contrasting burn characteristics. Location and topography, which constrain vegetation class, strongly determine FRP, and fire history is of lesser importance over the 19-year analysis period.

Conclusions

FRP can be used to identify wildfire consumption in dissimilar vegetation classes but is highly conditioned by geographic location. The complex and evolving vegetation composition of post-fire boreal landscapes precludes a clear association of expected FRP at distinct stages of recovery.

Implications

These results can inform further study of FRP as an indicator of fire behavior and fuel consumption and for informing dynamics of post-fire recovery across Alaska.

Flood-inundation maps for 14.8 miles of Little and Big Papillion Creeks in Omaha, Nebraska, 2023

Released May 21, 2025 08:56 EST

2025, Scientific Investigations Report 2025-5032

Kellan R. Strauch, Bradley R. Hoefer

Digital flood-inundation map libraries for two reaches that constitute 14.8 miles of Little and Big Papillion Creeks in Omaha, Nebraska, were created by the U.S. Geological Survey (USGS) in cooperation with the Papio-Missouri River Natural Resource District. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Program website at https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-mapping-fim-program, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at Little Papillion Creek at Irvington, Nebr. (USGS station 06610750), Little Papillion Creek at Ak-Sar-Ben at Omaha, Nebr. (USGS station 06610765), and Big Papillion Creek at Q Street at Omaha, Nebr. (USGS station 06610770) streamgages. Near-real-time stages at these streamgages may be obtained from the USGS National Water Information System database at https://doi.org/10.5066/F7P55KJN or from the National Weather Service Advanced Hydrologic Prediction Service at https://water.weather.gov/ahps/.

Flood profiles were computed for two different reaches that constitute 14.8 miles of stream length in the study area by using hydraulic models. The models were calibrated by adjusting roughness coefficients to best represent the current (2022) stage-streamflow relation at the streamgages within the study reach.

The hydraulic models were then used to compute water-surface profiles at 1-foot stage intervals for selected stage ranges to represent various flooding scenarios at the streamgages in each reach. The simulated water-surface profiles then were combined with a digital elevation model using a geographic information system, which had a 10-foot grid spacing to delineate the flooding extents and water depths for each stage. The availability of these flood-inundation maps, along with information regarding current stage from the USGS streamgages, can provide emergency management personnel and residents with information that is critical for flood response activities and post flood recovery efforts.

Framework for assessing intranational risk of critical mineral sectors: Case study of India

Released May 20, 2025 10:39 EST

2025, Resources Policy (106)

Keita Federico Decarlo

Recent geopolitical actions regarding the supply of critical minerals have highlighted both the threats posed by countries dominating a critical mineral supply chain, and the potential mitigations served by alternative supplier countries. However, no systematic quantification exists for the intranational factors that determine such threats or mitigations. This study outlines a methodological framework for quantifying the intranational risk profile of critical mineral sectors and compares them with the sector's international potential for leverage. The four intranational factors of concentration, synchronization, private sector involvement, and regulatory obstacles were analyzed across multiple scales in order to determine an intranational risk score that quantifies the resilience or fragility of the critical mineral sector in question. Network analysis was also separately conducted to identify the most important entities operating across all critical mineral sectors. Finally, this study assessed the critical mineral sector's global share of reserves and production to determine an international risk score that quantifies the country's critical mineral sector's leverage potential. A case study of India showed that two critical mineral sectors with high leverage potential, chromite and barite, were respectively intranationally resilient and fragile. Of the remaining sectors with minimal leverage, five sectors such as aluminum were intranationally resilient and may serve as viable mitigation options for future critical mineral supply. Three sectors such as titanium were intranationally fragile, but recent regulatory developments may both decrease intranational risk and increase international risk, potentially making them major critical mineral sectors in the future.

Clarifying the role of the resist–accept–direct framework in supporting resource management planning processes

Released May 20, 2025 09:22 EST

2025, Conservation Biology

Gregor W. Schuurman, Wylie Carr, Cat Hawkins Hoffman, David J. Lawrence, Brian W. Miller, Erik A. Beever, Jean Brennan, Katherine R. Clifford, Scott Covington, Shelley D. Crausbay, Amanda E. Cravens, John E. Gross, Linh Hoang, Stephen Jackson, Abraham J. Miller-Rushing, Wendy Morrison, Elizabeth A. Nelson, Robin O'Malley, Jay O. Peterson, Mark T. Porath, Karen Prentice, Joel H. Reynolds, Suresh A. Sethi, Helen Sofaer, Jennifer L. Wilkening

No abstract available.

Kiloyear cycles of carbonate and Mg-silicate replacement at Von Damm hydrothermal vent field

Released May 20, 2025 09:17 EST

2025, Geology

Amy Gartman, Terrence Blackburn, Kiana Frank, Susan Q. Lang, Jeffrey S. Seewald

The Von Damm vent field (VDVF) on the Mid-Cayman Rise in the Caribbean Sea is unique among modern hydrothermal systems in that the chimneys and mounds are almost entirely composed of talc. We analyzed samples collected in 2020 and report that in addition to disordered talc of variable crystallinity, carbonates are a major class of mineral at VDVF. The carbonate minerals include aragonite, calcite, magnesium-rich calcite, and dolomite. Talc and carbonate mineral textures indicate that, rather than replacing volcanic host rock, they precipitate from the mixing of hydrothermal fluids and seawater at the seafloor, occurring in chimneys and surrounding rubble. Alternating precipitation of this mineral assemblage is pervasive, with carbonate minerals typically being succeeded by talc, and with indications that in some cases talc and carbonate minerals replace one another. Stable carbon isotopic data indicate the carbonate minerals originate from the mixing of seawater and hydrothermal fluid, which is supported by U-Th data. Radiocarbon calcite ages and talc 234U-230Th isochron ages indicate mineral ages spanning over thousands to tens of thousands of years. Analyses of these samples illustrate a dynamic system that transitions from carbonate-dominated to Mg-silicate−dominated precipitation over time scales of thousands of years. Our observations raise questions regarding the eventual fate of seafloor precipitates and whether carbonate and silicate minerals in such settings are sequestered and represented in the rock record.

Flood of July 2023 in Vermont

Released May 19, 2025 14:50 EST

2025, Scientific Investigations Report 2025-5016

Travis L. Smith, Scott A. Olson, James M. LeNoir, Rena D. Kalmon, Elizabeth A. Ahearn

A major storm caused catastrophic flooding in many parts of Vermont on July 9–12, 2023, resulting in millions of dollars in damages. The high amount of rainfall caused several rivers to peak at record levels, in some cases exceeding records set during Tropical Storm Irene in 2011. The U.S. Geological Survey, in cooperation with the Federal Emergency Management Agency, collected and analyzed data that characterized the flood in Vermont. The data collected included peak water-surface elevations, taken from high-water marks at bridges, dams, and roads, and peak streamflow and annual exceedance probabilities (AEPs) at streamgages, lake gages, and selected ungaged locations. At 11 of the 80 streamgages with 12 to 94 years of record, the July 2023 peak streamflow was the peak of record. Ten streamgages recorded a peak streamflow with an AEP of less than or equal to 1 percent (greater than or equal to a 100-year recurrence interval).

The July 2023 flood affected many of the same communities as the historical flood caused by Tropical Storm Irene in 2011. Twenty of the 45 continuous-recording streamgages running during both events recorded greater peak streamflows during the July 2023 flood than during Tropical Storm Irene in 2011. Four of the 11 U.S. Geological Survey streamgages with period-of-record maximum peak streamflows observed during the July 2023 flood had previously recorded their maximum period-of-record peak streamflows during Tropical Storm Irene. There were 17 rivers in Vermont that were surveyed for high-water marks during both Tropical Storm Irene and the July 2023 flood. On those 17 rivers, a total of 103 sites contained surveyed high-water marks for both events. Thirty-two of these sites had higher surveyed elevations for the July 2023 flood than Tropical Storm Irene, including Black River in Newport, Black River in Springfield, Jewell Brook, Middlebury River, Missisquoi River, Ottauquechee River, Otter Creek, Wells River, Whetstone Brook, and Winooski River. Peak water-surface elevations were not collected on the Lamoille River in 2011.

Federal Emergency Management Agency flood insurance studies were evaluated in the context of the July 2023 flood. Peak streamflows at streamgages and nearby locations were assessed to determine the influence of the July 2023 flood on the AEPs used in past studies. Overall, 21 of 26 streamflow-computation locations in the flood insurance studies had more than a 10 percent difference in the 1-percent AEP streamflow. A hydraulic evaluation of surveyed water-surface elevations following the July 2023 flood was compared with the AEP profiles from past studies. Four of the 10 streamgages analyzed had poor alignment between the AEPs of the observed streamflows and the AEPs of the observed peak water-surface elevations as computed from flood insurance studies.

Peak streamflow trends in Montana and northern Wyoming and their relation to changes in climate, water years 1921–2020

Released May 19, 2025 13:20 EST

2025, Scientific Investigations Report 2023-5064-G

Steven K. Sando, Nancy A. Barth, Roy Sando, Katherine J. Chase

Frequency analysis on annual peak streamflow (hereinafter, peak flow) is essential to water-resources management applications, including critical structure design (for example, bridges and culverts) and floodplain mapping. Nonstationarity is a statistical property of a peak-flow series such that the distributional properties (the mean, variance, or skew) change either gradually (monotonic trend) or abruptly (shift, step change or change point) through time. Not incorporating or accounting for observed nonstationarity into peak-flow frequency analysis might result in a poor representation of the true probability of large floods and thus misrepresent the actual flood risks to life and property. This report summarizes how hydroclimatic variability might affect the temporal and spatial distributions of peak-flow data in the State of Montana (and northern Wyoming) and is part of a larger study to document peak-flow nonstationarity and hydroclimatic changes across a nine-State region consisting of Illinois, Iowa, Michigan, Minnesota, Missouri, Montana, North Dakota, South Dakota, and Wisconsin. A wide range of analyses and statistical approaches are applied to document the primary mechanisms controlling floods and characterize temporal changes in hydroclimatic variables and peak flows. This study was completed in cooperation with the Montana Department of Natural Resources and Conservation.

The purpose of this report is to characterize temporal and spatial patterns of nonstationarity in peak flows and hydroclimatology in Montana and northern Wyoming. In this evaluation, peak-flow, daily streamflow, and model-simulated gridded climatic data were examined for monotonic trends, change points, and other statistical properties that might indicate changing climatic and environmental conditions. This report includes background information on the study area, the history of U.S. Geological Survey peak-flow data collection and frequency analysis in Montana, and the review of research relating to hydroclimatic variability and change in Montana. This study might help provide a framework for addressing potential nonstationarity issues in peak-flow frequency updates that commonly are completed by the U.S. Geological Survey in cooperation with other agencies throughout the Nation.

The analytical structure of this study includes analyses of monotonic trends and change points in numerous hydroclimatic variables in assigned 30-, 50-, 75-, and 100-year analysis periods. For Montana and part of Wyoming, the 30-, 50-, 75, and 100-year analyses included 157, 70, 48, and 12 streamgages, respectively. For those streamgages, nonstationarities were analyzed in the following variables: (1) climatic variables, including annual and seasonal (winter, spring, summer, and fall) temperature and precipitation; (2) daily streamflow variables, including the annual center of volume duration, annual center of volume median, and peaks over threshold with a mean of four events per year; and (3) annual peak-flow variables, including peak-flow timing and magnitude. A likelihood approach was used to express statistical confidence and assign the nonstationarity results as likely upward or downward (highest statistical confidence), somewhat likely upward or downward (less statistical confidence), or about as likely as not (little statistical confidence; hereinafter, neutral). For the nonstationarity analyses of the climatic, daily streamflow, and peak-flow variables, the results are presented in detail and discussed with respect to statewide patterns and geographic variability. For each of the 30-, 50-, and 75-year analyses, peak-flow change-point and monotonic trend analyses were compiled for streamgages classified with likely downward or likely upward trends. For those streamgages, the associated basin characteristics and nonstationarity results for peak-flow timing, daily streamflow, and climatic variables were investigated and statistically compared to discern associations among other variables that might contribute to the peak-flow nonstationarity results.

The 50- and 75-year peak-flow nonstationarities identified in this study are mostly downward, in association with mostly upward temperature and potential evapotranspiration:precipitation monotonic trends. For the 50-, 75-, and 100-year analyses, the peak-flow change points are predominantly downward and are concentrated in the 1970s and 1980s, which indicates general consistency among the longer trend periods. These findings are in association with substantial research documenting globally rising temperature and atmospheric greenhouse gas concentrations that might be largely attributed to anthropogenic activities. Anthropogenic effects might represent long-term (on the order of several decades to more than a century) climate changes that might happen within highly variable natural climate fluctuations. Several paleo studies in the north-central United States have indicated that hydroclimatic extremes (that is, low- and high-streamflow conditions) before European settlement have been outside of extremes since the 1900s. Depending on the interactions of anthropogenic effects and natural climate variability, extreme high-streamflow conditions might occur in the future, even in the presence of long-term downward peak-flow trends.

Effects of riparian forest thinning on resident salmonid fishes in coastal northern California catchments

Released May 19, 2025 10:16 EST

2025, Freshwater Biology (70)

David A. Roon, Jason B. Dunham, Joseph R. Benjamin, Bret C. Harvey, James R Bellmore

  1. Resource managers are interested in whether thinning second-growth forests may be a viable restoration strategy for stream and riparian habitats, but may be concerned about the potential impacts that increases in stream temperature associated with riparian thinning treatments may have on cold-water salmonid fishes.
  2. We evaluated the effects of riparian forest thinning on resident populations of coastal cutthroat trout (Oncorhynchus clarkii clarkii) in coastal northern California catchments using a manipulative field experiment with a replicated before-after-control-impact design (pre-treatment data collected in 2016, thinning treatments occurred in 2017, and post-treatment data collected in 2018). Experimental thinning treatments reduced riparian shade by 20%–30% along five 150–200 m stream reaches. To provide a process-based evaluation of the implications of riparian thinning for coastal cutthroat trout, we combined seasonal observations of trout density, biomass, and growth with bioenergetics modelling.
  3. Cutthroat trout density increased by 8%–31% and biomass increased by 27%–111% in thinned reaches 1 year post-treatment, but responses varied widely across sites and seasons so did not always differ statistically. Growth rates of cutthroat trout varied more among seasons than among reach types (upstream reference, thinned, and downstream), peaking in spring and overwinter relative to summer.
  4. Bioenergetics modelling indicated that cutthroat trout responded to thinning-induced increases in stream temperature and shifts in prey energy density via higher consumption rates (i.e., fish fed more frequently) in thinned reaches. Additionally, reach-scale consumption estimates indicated that the energy intake of cutthroat trout increased at the population level in thinned reaches. However, thinned reaches exhibited relatively small changes in consumption, suggesting that riparian thinning was unlikely to enhance growth opportunities for cutthroat trout, supporting our empirical growth observations.
  5. Collectively, our field experiment suggests that salmonid fishes may be resilient to thinning second-growth riparian forests when treatments do not substantially increase water temperatures. Moreover, our results highlight that pairing empirical data with bioenergetics modelling can provide valuable insights into the mechanisms driving fish responses to riparian forest restoration.

Cave records reveal recent origin of North America’s deepest canyon

Released May 19, 2025 09:44 EST

2025, Proceedings of the National Academy of Sciences (122)

Matthew Morriss, Nate Mitchell, Brian Yanites, Lydia M. Staisch, Oliver Korup

We explore how and when Hells Canyon, North America’s deepest river gorge (~2,400 m deep), formed, addressing these fundamental questions first posed by W. Lindgren [The Gold Belt of the Blue Mountains of Oregon (1901)]. Existing hypotheses about the canyon’s formation and timing of incision remain speculative due to a lack of direct constraints and geomorphic analysis in the canyon. Herein, we combine cosmogenic nuclide dating of cave-bound river deposits, river profile analysis, and numerical modeling to provide the first direct age constraints and systematic analysis of incision processes at work in Hells Canyon. Our study reveals a significant drainage capture triggered rapid incision at ~2.1 ± 1.0 Ma, establishing the Snake River’s modern route into the Columbia River system. The increased drainage area and subsequent increase in stream power resulted in the rapid incision of Hells Canyon and the formation of tributary knickpoints (KPs) that decrease in elevation away from the capture location. Cosmogenic dating of cave deposits indicates incision rates increased from ~0.01 to ~0.16 mm y−1. Numerical modeling of the stream capture supports these observations, demonstrating how abrupt drainage area increase drives rapid river incision. Our findings from Hells Canyon provide a well-constrained example of how drainage capture can dramatically shape the evolution of a major river gorge.

Diagnostic success—A quick guide to quality carcass submissions for diagnostic services

Released May 19, 2025 09:21 EST

2025, Fact Sheet 2025-3024

Barbara L. Bodenstein, Shelby Jo Weidenkopf

The U.S. Geological Survey National Wildlife Health Center provides diagnostic services to determine causes of wildlife morbidity and mortality events to State, Federal, and Tribal partners. To accomplish this, we rely on the timely collection and evaluation of submitted carcasses and the epidemiologic information relayed from personnel in the field. Our current submission criteria can be found here: https://www.usgs.gov/centers/nwhc/science/ diagnostic-case-submission-guidelines. If the majority of carcasses found in the field are unsuitable for submission, then sick animals (birds, mammals, reptiles) that have been euthanized are acceptable specimens. Depending on the agency or affiliated institution, there may be additional requirements for submission. When applicable, always consult the organization’s wildlife health or veterinary staff.

Serological assessment of pathogen exposure among desert bighorn sheep in southwestern Arizona

Released May 19, 2025 08:50 EST

2025, The Southwestern Naturalist (68) 294-300

Colton J. Padilla, James W. Cain III, Matthew E. Gompper, Paul R. Krausman, JIM Devos

Bighorn sheep (Ovis canadensis) are influenced by infectious diseases. Although Mycoplasma ovipneumoniae has been the main focus of bighorn sheep managers since early 2010, other pathogens may also influence bighorn sheep populations. We sampled desert bighorn sheep (Ovis canadensis mexicana) captured for a study on the Cabeza Prieta National Wildlife Refuge in southwestern Arizona, USA, 2001–2005, for a suite of pathogens: bluetongue (BT), epizootic hemorrhagic disease (EHD), parainfluenza 3, bovine respiratory syncytial virus, Clamydia, seven Leptospira serovars, bovine herpesvirus 1 (causative agent of infectious bovine rhinotracheitis), bovine viral diarrhea virus, and bovine respiratory syncytial virus. We recorded evidence of exposure to seven of these pathogens, with two Leptospira serovars (hardjo and bratislava), five strains of BT, and two strains of EHD detected. Seroprevalence rates of detected pathogens varied between 12–49%. We observed high levels of co-occurrence for EHD and BT. These results highlight that multiple pathogens may influence desert bighorn sheep populations. These data also provide historical context to pathogen exposure for a region where few such data are available.

Cultivating reciprocity and supporting Indigenous lifeways through the cultural transformation of natural resource management in North America

Released May 19, 2025 08:47 EST

2025, People and Nature (7) 1171-1184

Jonathan Fisk, Richard E.W. Berl, Jonathan W. Long, Jacobs. Lara, Lily van Eeden, Melinda Adams, Álvaro Fernández-Llamazares, Jazmin Murphy, Michael C. Gavin, Chris K Williams, Jonathan Salerno, Bas Verschuuren, Nathan Bennett, Rodrigue Idohou, Alexander Mawyer

  1. Recent decades have seen increasing calls for implementing Indigenous Knowledges (IK) in natural resource management (NRM). However, efforts have been limited by the cultural incommensurabilities between (1) NRM institutions, which are rooted in worldviews that prioritize extraction for dominant cultures and assume dominance over nature and (2) Indigenous worldviews that prioritize kincentric reciprocity with the environment. This manuscript addresses how transforming NRM institutions enables management to better support Indigenous Knowledges and lifeways.
  2. This manuscript examines incommensurabilities between NRM institutional cultures and Indigenous cultures, with the value and lifeway of reciprocity as the focal point. Through synthesizing interdisciplinary scholarship and examples from author experiences, we explore how NRM institutions in North America can transform to honour and facilitate reciprocity, especially within efforts to implement IK and support Indigenous lifeways.
  3. NRM institutions are cultural products, and in North America were born of colonial histories and cultural roots connected to modern governance and power dynamics. These cultural foundations led to NRM approaches that prioritize maximizing economic growth while guarding against overexploitation. Kincentric reciprocal relations with the environment often emphasize interdependency with more-than-human kin, place-based holistic Knowledges grounded in cultural practices and communal responsibility to cultivate social-ecological abundance for present and future generations. Incommensurabilities between NRM institutional cultures and Indigenous cultures impede efforts to implement IK and support Indigenous lifeways as: (1) rigid institutional structures do not account for Indigenous worldviews and values but instead attempt to fit IK within dominant paradigms; (2) the siloing of NRM leads to the piecemealing and invalidation of IK at the expense of Knowledge Holders and (3) ineffective public engagement strategies limit the possibility of reciprocal relations between NRM institutions and communities throughout management processes.
  4. Incommensurabilities between NRM institutional cultures and Indigenous cultures impede efforts to implement IK and support Indigenous lifeways as: (1) rigid institutional structures do not account for Indigenous worldviews and values but instead attempt to fit IK within dominant paradigms; (2) the siloing of NRM leads to the piecemealing and invalidation of IK at the expense of Knowledge Holders and (3) ineffective public engagement strategies limit the possibility of reciprocal relations between NRM institutions and communities throughout management processes.
  5. Transforming NRM institutional cultures to better implement IK and support Indigenous lifeways is key for redressing long-standing issues and ensuring social-ecological resilience and abundance. Heavy investments of time, personnel and resources are necessary for transforming NRM institutions to appropriately cultivate reciprocal relations with Indigenous communities and lands. Strategies towards transformation include decentralization through decolonial frameworks, knowledge co-production and using place-based cultural evaluation processes to improve cultural alignment.

Are wildfire risk mitigators more prepared to evacuate? Insights from communities in the western United States

Released May 19, 2025 08:02 EST

2025, Ecological Economics (236)

Grant Webster, Hannah Brenkert-Smith, Patricia A. Champ, James R. Meldrum, Kelly Wallace, Colleen Donovan, Carolyn Wagner, Christopher M. Barth, Josh Kuehn, Suzanne Wittenbrink, Christine Taniguchi

As the realized experiences of wildfires threatening communities increase, the importance of proactive evacuation preparation and wildfire risk mitigation on private property to reduce the loss of lives and property is shaping wildfire policy and programs. To date, research has focused on pre-wildfire evacuation preparation and risk mitigation independently. This paper examines the substitutability or complementarity of these proactive risk-reducing actions. If mitigation and evacuation preparedness are substitutes, wildfire education programs may take a life-over-property approach. However, if proactive risk-reducing efforts are complements, wildfire education programs can confidently encourage residents to prepare for evacuation while also mitigating wildfire risk on their properties. This complementarity may also demonstrate that poorly mitigated households are less prepared to evacuate, compounding their risks. Using household survey data from 25 wildland-urban interface (WUI) communities across five Western states, we explore how wildfire risk mitigation actions affect evacuation preparedness. We find that improving household wildfire mitigation is associated with an improvement in wildfire evacuation preparedness. This complementary relationship between wildfire mitigation and evacuation preparedness actions highlights the potential benefits of a wildfire education approach that encourages residents to simultaneously prepare for evacuation and reduce wildfire risk on their properties before they are threatened by a wildfire.

Independent and interactive effects of disease and methylmercury on demographic rates across multiple amphibian populations

Released May 19, 2025 07:53 EST

2025, Scientific Reports (15)

Morgan P. Kain, Blake R. Hossack, Kelly Smalling, Brian J. Halstead, Daniel A. Grear, David A. Miller, Michael J. Adams, Adam R. Backlin, William Barichivich, Collin A. Eagles-Smith, Colleen Emery, Jillian Elizabeth Fleming, Robert N. Fisher, Elizabeth Gallegos, Duoa J. Lor, Patrick M. Kleeman, Erin L. Muths, Ty Pan, Christopher Pearl, Charles W. Robinson, Caitlin Teresa Rumrill, Brian J. Tornabene, J. Hardin Waddle, Susan Walls, Evan H. Campbell Grant

Disease, alone or combined with other stressors such as habitat loss and contaminants, affects wildlife populations worldwide. However, interactions among stressors and how they affect demography and populations remain poorly understood. The amphibian chytrid fungus (Batrachochytrium dendrobatidis; Bd) is a sometimes-lethal pathogen linked with population declines and extirpations of amphibians globally. Laboratory evidence shows ubiquitous contaminants like methylmercury (MeHg) can reduce vigor and survival of amphibians, but population-level effects remain unclear. We used non-lethal sampling to assess how Bd and MeHg affected survival of juvenile and adult amphibians in 20 populations across the USA. Survival of several species declined with increasing Bd loads, including some species previously considered resistant to Bd (e.g., eastern newt [Notophthalmus viridescens]). Although our sampling for MeHg was less intensive than for Bd, we found MeHg can both directly reduce survival and synergistically magnify the effects of Bd infection. For a population of foothill yellow-legged frogs (Rana boylii), the estimated reduction in survival from MeHg exceeded that from Bd. Although effects varied widely among populations and species, our results help clarify the potential for synergistic effects of disease and contaminants and emphasize the complexity of identifying and quantifying the population-level effects of interactions among stressors.

A review of standardization in Mississippi’s multidecadal inland fisheries monitoring program

Released May 18, 2025 09:27 EST

2025, Fishes (10)

Caleb A. Aldridge, Michael E. Colvin

Standardizing data collection, management, and analysis processes can improve the reliability and efficiency of fisheries monitoring programs, yet few studies have examined the operationalization of these tasks within agency settings. We reviewed the Mississippi Department of Wildlife, Fisheries, and Parks, Fisheries Bureau’s inland recreational fisheries monitoring program—a 30+-year effort to standardize field protocols, data handling procedures, and automated analyses through a custom-built computer application, the Fisheries Resources Analysis System (FRAS). Drawing on quantitative summaries of sampling trends and qualitative interviews with fisheries managers, we identified key benefits, challenges, and opportunities associated with the Bureau’s standardization efforts. Standardized procedures improved sampling consistency, data reliability, and operational efficiency, enabling the long-term tracking of fish population and angler metrics across more than 270 managed waterbodies. However, challenges related to analytical transparency and spatiotemporal comparisons persist. Simulations indicated that under current conditions, 5.8, 22.9, and 37.1 years would be required to sample (boat electrofishing) 50%, 75%, and 95% of the Bureau’s waterbodies at least once, respectively; these figures should translate to other agencies, assuming similar resource availability per waterbody. The monitoring program has reduced manual processing effort and enhanced staff capacity for waterbody-specific management, yet several opportunities remain to improve efficiency and utility. These include expanding FRAS functionalities for trend visualization, integrating mobile field data entry to reduce transcription errors, linking monitoring results with management objectives, and enhancing automated report generation for management support. Strengthening these elements could not only streamline workflows but better position agencies to apply standardized data in adaptive management embedded into the monitoring program.

A joint Gaussian process model of geochemistry, geophysics, and temperature for groundwater TDS in the San Ardo Oil Field, California, USA

Released May 18, 2025 09:08 EST

2025, Journal of Hydrology (661)

Michael J. Stephens, Will Chang, David H. Shimabukuro, Amanda Howery, Theron Sowers, Janice M. Gillespie

Decline in availability of fresh groundwater has expanded interest in brackish groundwater resources; however, the distribution of brackish groundwater is poorly understood. Water resources in sedimentary basins across the United States often overlie oil and gas development. Mapping of groundwater total dissolved solids (TDS) using data from oil well geophysical logs has become an important technique for identifying fresh and brackish groundwater.
Existing geophysical log analysis methods use porosity and temperature to relate formation resistivity to TDS. Typically, natural geothermal gradients are used to estimate temperature at the location of collected resistivity. However, in thermally enhanced oil fields, steam is injected into the subsurface to mobilize high viscosity oil, creating variable temperature distributions. Furthermore, TDS derived from resistivity also depends on the fractions of dominant ions. Typically, chloride and bicarbonate fractions must be determined. It is also necessary to model TDS across many geologic units with heterogenous porosity distributions. Collectively, each quantity used to estimate TDS (resistivity, porosity, temperature, bicarbonate fraction) varies in space and time, and available data points are rarely collocated.
Here, we present a new method of mapping groundwater TDS that continuously models each quantity together with a joint Gaussian process. This method enables mapping fresh and brackish water with practically available data. We apply this method to the San Ardo Oil Field in Monterey County, California, where steam injection occurs. In some areas of the aquifer system overlying the oil zone, the temperature is ∼75 °C, roughly twice the natural background value. Groundwater TDS is typically <1,500 mg/L in the aquifer and increases with depth to ∼9,000 mg/L in the oil-producing zone. A low-permeability clay layer delineates the fresh and brackish water, likely by inhibiting surface recharge from penetrating the deeper zones, allowing higher-TDS connate water to remain in place. Weaker lateral TDS trends may be controlled by recharge patterns associated with the Salinas River. Our model reveals with high certainty that groundwater has freshened in one localized part of the oil-producing zone and suggests with less certainty that more widespread freshening has also occurred. The lowering of TDS was possibly from decades of low-TDS steam injection and the associated fluid production and disposal operations.