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At least 649 records · Page 36Linked to original sources
USGS2026

Dietary composition and diversity in an endemic island bat, the Hawaiian hoary bat (Lasiurus semotus)

Due to the importance of sufficient diets, conservation practices for endangered bats often involve protection and restoration of foraging resources. For insectivorous (or arthropodivorous) bats, detailed knowledge of prey consumption can inform effective management. In this study, we used metabarcoding techniques to investigate the diet of Lasiurus semotus , a primarily insectivorous, solitary foliage-roosting endangered bat endemic to the Hawaiian Islands. To determine diet composition and how it relates to sex, reproductive condition, and habitat, we analyzed 141 guano samples collected from across the Hawaiian archipelago between 2010–2021. We detected 424 arthropod prey items, with Lepidoptera — the most common order (found in 100% of all samples), followed by Blattodea (85%), Coleoptera (42%), Orthoptera (47%), Diptera (33%), and Hemiptera (25%). Coleoptera were more frequent in guano collected from females. Prey richness and evenness at the family-level were similar across sex, reproductive condition, elevation, and land cover type. High variability among samples, and the dominance of Lepidoptera and Kalotermitidae (Blattodea), indicates that local prey abundance may influence L. semotus diet more strongly than prey richness and evenness. Lasiurus semotus consumed both native and non-native arthropods, including several invasive agricultural pests. Our study demonstrates that hoary bats in the Hawaiian Islands consume a wide variety of prey types, likely sought over an extensive range of habitats.

Hawaii↗
USGS2026

Comparative genomics reveals potential mechanisms of invasion in Phragmites australis (common reed)

Biological invasions are transforming ecosystems worldwide, yet the genomic bases enabling certain species to dominate new environments remain poorly understood. Phragmites australis , a widespread wetland grass with invasive and native subspecies co-occurring in North America, provides a powerful system to investigate genomic mechanisms of invasiveness. We generated independent chromosome-scale genome assemblies for invasive P. australis ssp. australis and co-occurring native ssp. americanus and used comparative genomic and transcriptomic analyses to identify lineage-specific innovations associated with invasive success. The invasive subspecies exhibits genomic novelties through functionally-biased single-copy orthologs, intronless genes, and subgenome expression asymmetry, along with a stress-ready basal transcriptome relative to the native subspecies. Following the removal of aboveground shoots (“cutback”), which measures the ability to recover from damage, the invasive subspecies undergoes stronger transcriptional reprogramming, increased shoot production, and higher biomass accumulation compared to the native. It also displays expansion of gene families and coordinately expressed gene modules that support resource mobilization, growth responses to light, and stress tolerance. Beyond Phragmites , comparative analyses across multiple grass genomes, including eight invasive species with related non-invasive species, revealed repeated expansion of gene families associated with abiotic stress tolerance and developmental regulation, suggesting convergent adaptive strategies in the grass family for invasive success. Together, these results demonstrate genomic architecture linked to invasion success and highlight potential targets for managing invasive grasses.

BioRxiv↗
USGS2026

Morphodynamic controls on the performance of dune-based coastal flood mitigation under sea-level rise

Dune-based adaptation is increasingly used as a nature-based solution for coastal flood mitigation, yet many assessments rely on hydrodynamic-only approaches that treat beach and dune morphology as static, neglecting storm-driven erosion that can degrade dune performance during extreme events. This study develops a process-based modeling framework coupling extreme value analysis of regional wave climate with XBeach surfbeat simulations to evaluate coastal flooding, erosion, and dune performance across three time horizons (2025, 2055, 2085) and four storm return periods (5, 20, 50, and 100 years) at two contrasting sites in Santa Cruz County, California. At Santa Cruz Beach, flood extent increases at an accelerating rate with sea-level rise (SLR) for a given return period, while higher return period storms exhibit diminishing incremental increases under fixed SLR conditions. Storm-scale morphodynamic feedbacks reduce predicted flood extent by up to 32.4% through profile adjustment and nearshore bar formation. Dune effectiveness is strongly regime-dependent, reducing flooding by up to 60% under collision-regime conditions but declining rapidly as the system transitions toward overwash and inundation under stronger storms and late-century SLR. Comparison of static and erodible dune representations shows that flood estimates are not consistently conservative, with differences reaching up to 54.3% depending on storm intensity and time horizon. At Capitola Beach, limited accommodation space and water-level-dominated dynamics collectively constrain morphodynamic adjustment, render the site near its inundation capacity under present-day conditions, and result in near-complete dune collapse and limited flood mitigation across all scenarios. These findings highlight the importance of site-specific regime evaluation, process-based morphodynamic modeling, and adaptive management when assessing dune-based adaptation under rising sea levels.

California↗
USGS2026

Evidence for a biological origin of uranium-rich carbon masses within the Ediacaran Salt Range Formation of Pakistan

Thucholites are unique organic structures found in igneous and sedimentary rocks composed of a U-C-rich interior enclosed by an organic outer shell. Their formation and occurrence have perplexed scientists for over 100 years. Typically, thucholites are sparse in sedimentary rocks but where found in abundance, they may be the result of rapid paleoecological disruptions, e.g., volcanic ashfall. Here, we evaluated thucholites from the Ediacaran Salt Range Formation of the Indus Basin in Pakistan using field emission scanning electron microscopy (FESEM) and nanoscale secondary ion mass spectroscopy (NanoSIMS) to propose a two-stage mechanism for thucholite development. NanoSIMS results suggest organic matter in thucholite cores formed by biological fractionation (represented by the presence of lighter 13 C/ 12 C and 34 S/ 32 S) while the outer organic mantle formed via radiolysis-induced polymerization. FESEM elemental analysis confirms compositional differences between the two thucholite components (core and mantle), further implying their contrasting origins. Dimensional comparison of thucholite cores and their U-bearing mineral morphologies to ancient and modern U-biomineralized microbes suggests that the thucholite cores formed from metal-biological interactions. The presence of volcanogenic biotite, alkali feldspar, and clay spherules (interpreted as devitrified volcanic glass) with thucholite suggests that the thucholite cores in the Salt Range Formation are biological responses to rapid paleoenvironmental change from volcanic eruption which preserved the fossilized morphologies of Proterozoic microorganisms.

Salt Range↗
USGS2026

Exploratory ecology of reintroduced elk in Virginia

Reintroductions of extirpated species are an important tool in wildlife conservation. Understanding how reintroduced populations acclimatize to novel environments can lend insight into social learning that in turn is valuable for assessing reintroduction success and maximizing efficacy of subsequent efforts. During 2012, 2013, and 2014, the Virginia Department of Wildlife Resources implemented soft releases of elk ( Cervus canadensis ) translocated to southwestern Virginia from eastern Kentucky. We investigated home range establishment and post-release movements of these reintroduced elk ( n = 60). We found adults moved farther from the release site than either yearlings or calves (F = 6.93, p = 0.001). Elk released in 2012 and 2013 took similar amounts of time to establish home ranges (median 181 days, range 108–214 days; and median 189 days, range 147–209 days, respectively), but individuals released in 2013 remained closer to the release site ( 𝑥 ̲ = 605.5 m, SD = 335.7 m, closer) presumably by joining established social groups. However, the 2014 cohort generally took longer to establish home ranges (median: 231 days; range: 56–258 days) and moved farthest from the release site ( 𝑥 ̲ = 1360.2 m, SD = 293.9 m, farther than 2012 individuals) possibly due to the larger cohort size and resulting intraspecific competition, or the earlier release date that year. Our findings suggest the number of consecutively released cohorts, the timing of the release, and the composition of age classes for released individuals are important considerations for reintroductions.

Virginia↗
USGS2026

Carryover effects across juvenile periods vary by species, cause-specific mortality, and stage-specific behavior

Conditions during one life-stage can carry over to influence fitness outcomes in later stages. How carryover effects manifest, however, may vary depending on the type and magnitude of risks that animals face in subsequent life-stages. The influence of carryover effects on cause-specific mortality remains largely unclear, particularly during vulnerable life-stages, including juvenile periods. We proposed and investigated the Cause-specific carryover hypothesis, that the relative influence of traits developed during a previous stage on mortality during the next vary by cause of mortality, using juvenile sagebrush songbirds (Brewer’s sparrow, Spizella breweri ; sagebrush sparrow, Artemisiospiza nevadensis ; sage thrasher, Oreoscoptes montanus ) as a focal system. We tracked birds during the post-fledging period (a juvenile period following the nestling period), identified the rates and causes of mortality, and tested the relative influence of different nestling traits (wing length, tarsus length, feather development, and body condition) on post-fledging mortality risk. Carryover effects varied across co-occurring species and differed by cause of mortality, and tarsus length had an unexpected and outsized impact on predation risk in the two sparrows. Although wing morphology typically is considered the most important trait for mobility in birds, most mortalities occurred during the first 5 days of the post-fledging period when altricial fledglings were incapable of flight and likely relied on running or scrambling ability to escape predators. Therefore, carryover effects were driven by stage-specific behavior during the period of highest risk. Developing animals may face investment trade-offs between morphological traits that influence different types of risk during different subsequent stages.

Wyoming↗
USGS2026

Osmium isotope constraints on Mauna Loa–Kilauea magmatic connectivity, Island of Hawai‘i

The Hawaiian volcanic chain exhibits a long-recognized double track of volcanism defined by the Loa and Kea trends, which erupt chemically and isotopically distinct lavas. Mauna Loa and Kīlauea, the two most frequently active volcanoes of the Loa and Kea trends, produce distinct endmember compositions. However, historical periods of compositional convergence have prompted debate regarding a potential magmatic connection between the two adjacent volcanoes. Proposed links include a shallow edifice-level plumbing system, a common magma source at ∼40 km depth, or a deeper asthenospheric source. In the latter scenario, based on correlated Sr–Nd–Pb isotopes and trace-element systematics, a “shared” mantle source supplies melt alternately to both volcanoes on multi-decadal timescales. Here, we use Os isotopes to evaluate the proposed connections. We measured Os isotopes in eight historical Mauna Loa tholeiites along with three Kīlauea tholeiites (1832 summit eruption; Uēkahuna Bluff; 2000 Pu‘u‘ō‘ō eruption) previously identified as isotopically intermediate between Mauna Loa and Kīlauea endmembers. We found that the acidic bromide leachates of all samples yield more radiogenic 187 Os/ 188 Os than corresponding bulk residues, with the labile Os-bearing phase comprising ∼0.4–27% of bulk Os. Mauna Loa tholeiites display nearly constant 187 Os/ 188 Os over the past ∼200 years (0.134–0.136; mean = 0.1357 ± 0.0013, n = 8, 2SD), despite large variations in total [Os] ranging from ∼30 pg/g (2022 tholeiite) to ∼966 pg/g (1868 picrite). The Kīlauea 1832 sample has 187 Os/ 188 Os = 0.1302 ± 0.0008, slightly higher than the Kīlauea endmember (0.1285 ± 0.0008), whereas the Uēkahuna Bluff and Pu‘u‘ō‘ō samples exhibit more elevated ratios (0.1314 ± 0.0008 and 0.1327 ± 0.0008, respectively). We conclude that the “shared” mantle source exerts negligible control on Mauna Loa Os isotope systematics. In contrast, the Kīlauea mantle source is more heterogeneous, with contributions from small-scale recycled domains with variable time-integrated Re/Os ratios.

Hawaii↗
USGS2026

Bayesian belief network model to predict human-wildlife conflict in protected areas

Human-wildlife conflict (HWC) poses a pervasive global challenge, affecting livelihoods and threatening biodiversity. To better anticipate and mitigate HWC risk, we developed a large-scale predictive model using a Bayesian Belief Network (BBN). We surveyed 1,011 park rangers across 135 terrestrial protected areas in three Andean countries, documenting recent HWC incidents involving wildlife persecution or killing, livestock depredation, crop damage, or threats to human safety and property. We identified key drivers of HWC risk, including governance, wildlife acceptance, participation, and habitat quality. A sensitivity analysis revealed that enhancing governance and improving wildlife acceptance could reduce HWC risk by > 85%. The BBN model demonstrated scalability, effectively identifying strategies to reduce HWC risk at multiple scales, from individual protected areas to national networks. Our findings highlight the importance of strengthening governance, increasing wildlife acceptance, and enhancing community participation in conservation efforts. BBNs provide a flexible, cost-effective, and data-driven tool to guide protected areas and wildlife managers in monitoring, anticipating, and making informed decisions to mitigate conflict and promote coexistence.

Scientific Reports↗
USGS2026

Cultural benefits knowledge and social learning in Elwha River dam removal and ecosystem decision-making

In a retrospective case study of the seminal Elwha River dam removal in Washington State, USA, we explore pathways through which ecosystem services (ES) knowledge can inform environmental decision-making. We specifically investigate how knowledge of cultural benefits linked to the Elwha River ecosystem was made available. Through interviews and historical document review we identify diverse forms of cultural benefits knowledge (i.e., how individuals or groups know the contributions of an ecosystem to their identities, experiences, and capabilities), including both knowledge in the form of practices – embodied or enacted forms of knowledge, and knowledge in the form of products – quantitative or written documentation. Recognizing and learning from the diverse forms in which benefits knowledges are conveyed can support more accurate and equitable consideration of the diverse values, well-beings, and human-nature relationships linked to ecosystems. With this case study, we illuminate pathways for meaningful consideration of multiple knowledge forms, and the plural ecosystem values they convey, with relevance for environmental decision processes in the Puget Sound and beyond.

Washington↗
USGS2026

An integrated drought early warning system to support coldwater fisheries management

Low streamflow resulting from drought and human water use is a threat to freshwater fisheries throughout western North America, creating a need for effective tools to aid management and fisheries use. We developed a drought early warning framework that forecasts river conditions that could result in temporary fishery closures and restrictions across Montana’s renowned trout fisheries. This tool provides reach-specific, probabilistic decision support for proactive management under drought conditions. We calibrated statistical models using historical streamflow and stream temperature data from U.S. Geological Survey (USGS) gauges to predict the likelihood of exceeding the low-flow and high-temperature thresholds for fisheries closure within 1- to 4-week outlooks during the warm season (May–October). These forecasts demonstrated consistently high model performance in predicting the criteria for low-flow fishing closure across all rivers (4-week outlook: mean R 2 = 0.96, IQR [interquartile range]: 0.94–0.97) and variable but often high model performance for temperature-based restriction criteria (mean R 2 = 0.80, IQR: 0.55–0.86), particularly at sites that frequently experience higher stream temperature conditions. This drought early warning system—available via the web-based tool TroutCast ( https://www.usgs.gov/apps/troutcast/ )—provides daily updated seasonal forecasts to help anticipate effects to recreational fishing opportunities. By quantifying forecast uncertainty and providing reach-specific probabilities, the system supports proactive management, improves coordination between fisheries and water managers, and provides stakeholders with actionable information on probable future effects on fishing access within a framework that is broadly applicable to other freshwater systems and water resource management challenges.

Montana↗
USGS2026

Preliminary geology of the North Meadow Creek Area, Tobacco Root Mountains, southwest Montana: The North Meadow Creek Fault

This report documents a previously unmapped fault, informally referred to herein as the North Meadow Creek fault, on the east flank of the Tobacco Mountains of southwestern Montana. This fault has an apparently long and complex history, including Quaternary offset of an older alluvial terrace, offset of a debris flow of presumed Pleistocene age, offset of rhyolite lava flows of presumed Tertiary age from their presumed source several kilometers east, on the opposite side of the fault, and offset and possible rotation of blocks of Archean gneiss on northeast side of the fault. The western part of the fault is covered by glacial moraines of two apparent ages, both Pleistocene.

Montana↗
USGS2026

Development of a two-dimensional hydraulic model for the Kalamazoo River between the Trowbridge and Allegan City Dams, Michigan

The U.S. Geological Survey developed a two-dimensional hydraulic model for a 9.2-mile reach of the Kalamazoo River between the Trowbridge and Allegan City Dams. The model simulates streamflow conditions with spatial coverage and resolution that would be difficult or dangerous to document with field measurements, enabling assessments of habitat connectivity and substrate stability to support dam removal and restoration planning. The model was calibrated with surveyed water surface elevation (WSE) profiles, streamgage WSE time series, and measured depth-average velocities. Modeled WSE profiles had root mean square error (RMSE) values of 0.20 and 0.32 foot. Cross-sectional average velocities were slightly underpredicted, with RMSE of 0.28 and 0.30 foot per second (ft/s). Channel roughness varied with stage, and the high-flow model reproduced streamgage WSE time series with an RMSE of 0.04 foot. Quasi-steady simulations at 4,000 cubic feet per second (ft 3 /s), about the 50-percent annual exceedance probability streamflow, indicated that cross-sectional average velocities within 3.4 miles downstream from Trowbridge Dam were commonly between 3 and 4 ft/s, occasionally exceeding 4 ft/s. Farther downstream, velocities seldom exceeded 3 ft/s. Simulated shear stresses were used to estimate substrate stability in the reach. At 4,000 ft 3 /s, the minimum stable grain size along most of the main channel was predicted to be in the pebble range (4–64 millimeters), and sands and silts were predicted to be stable in the floodplain and backwaters.

Michigan↗
USGS2026

Method development and validation for microscopic measurement of the fluorescence spectrum of sedimentary organic matter in geologic samples

The goal of this study was to develop and validate a standard operating procedure for measuring the fluorescence emission of sedimentary organic matter (SOM), a proxy used to assess thermal maturity conditions in petroliferous basins. We tested the performance of a spectrometer integrated with an epi-fluorescence imaging microscope, and evaluated instrument calibration, dark-current correction, time duration for instrument stabilization, light delivery optimization, and the number of measurements necessary to optimize precision. These tests were used to guide instrument operation, ensure measurement accuracy, and characterize performance limitations of the system as SOM transitions to higher thermal maturity with accompanying signal deterioration. Adhering to these newly established guidelines enhances the reproducibility of fluorescence spectroscopy measurements. More importantly, this work endeavors to reach the overall objective of demonstrating the utility of fluorescence spectroscopy for evaluating the thermal maturity of SOM. Method for fluorescence spectroscopy of sedimentary organic matter. Internal calibration via diffuse halogen light reflected from polytetrafluoroethylene (PTFE). Evaluates emission response via λ max and red-green and blue-green quotients.

MethodsX↗
USGS2026

A review of extraction techniques for per- and polyfluoroalkyl substances in graminaceous plants

Per- and polyfluoroalkyl substances (PFAS) are a wide-ranging class of manufactured chemicals that are environmentally persistent. Due to their ubiquity and resistance to degradation, PFAS readily bioaccumulate in a variety of environmental matrices and elicit a range of toxicological impacts. Despite an increase in research into these compounds, there is a clear gap in consensus on extraction techniques to quantify many PFAS in certain environmental media, particularly at critical points in agricultural food systems such as pasture grasses and feedstocks. Developing methods for more comprehensive and accurate extraction of PFAS in plant tissues is crucial for the biomonitoring of PFAS contamination in these ecosystems. This review seeks to identify relevant information pertaining to the partitioning of PFAS in plant matrices and evaluate the performance of previously established methods for the extraction of PFAS in graminaceous plants. Evaluated methods varied widely in extraction techniques, limits of detection and accuracy. This review provides a framework for enhancing PFAS analysis by tailoring extraction and cleanup strategies to both complex plant matrices and diverse analyte properties. Standardizing these methodologies will provide the high-quality data essential for ecotoxicologists and policymakers to accurately map the metabolic fate and ecological risks of these pollutants across food webs.

Critical Reviews in Analytical Chemistry↗
USGS2026

Disease-associated mortality drives reduction in Yukon River Chinook salmon escapement: A novel method for quantifying the negative impacts of ‘misfit’ parasites to improve fisheries management

Parasites can suppress host populations through parasite-induced mortality. However, the negative effects of parasites are difficult to measure in wild populations and we have few tools for quantifying the magnitude of parasite-induced mortality. This is especially true for many ‘misfit’ parasites that do not fit into standard classifications (e.g. fungal-like parasites and myxozoans). As such, we are limited in our ability to include the effects of parasites in fish and wildlife management strategies. Chinook salmon ( Oncorhynchus tshawytscha ) are a species of immense cultural and ecological significance but populations are declining across much of their range. In the Yukon River, Alaska, USA, episodic outbreaks of the ichthyosporean parasite Ichthyophonus have been linked to declines, but population-level effects of Ichthyophonus on Yukon Chinook salmon remain largely unknown. We developed a novel model that leverages changes in parasite intensity distributions to quantify the magnitude of disease-induced mortality occurring in host populations. We used it to address two questions to inform management of Yukon Chinook salmon: (i) Is parasite-induced mortality occurring in Chinook salmon and at what magnitude? (ii) What are the drivers of spatio-temporal variability in parasite-induced mortality? Using 3 years of surveys, we quantified the evidence for the presence, magnitude, and variability in Ichthyophonus -induced mortality in Chinook salmon. Our model predicted that Ichthyophonus was responsible for between 8% and 15% mortality of the migrating Chinook salmon population prior to reaching the Canadian border and could describe nearly 35% of unaccounted for mortality at the border. The model predicted that variability in mortality among years could largely be explained by differences in parasite acquisition in the marine environment rather than differences in infection dynamics in the river. Synthesis and applications . Alaska Department of Fish and Game is implementing an annual monitoring program at the mouth of the Yukon River where our model will estimate the proportion of fish at risk from parasite-induced mortality to inform annual management. Moreover, the model is broadly applicable to other fungal-like and myxozoan parasites of conservation concern, where improved estimates of parasite-induced mortality could be used to predict parasite suppression of wild and managed host populations.

Alaska↗