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At least 829 records · Page 46Linked to original sources

USGS2026

Vulnerability of the petroleum sector to volcanic hazards: Application to multi-hazards at Taranaki Mounga volcano, Aotearoa New Zealand

Volcanic eruptions can cause substantial damage and disruption to infrastructure and communities. Contemporary societies typically depend on petroleum infrastructure. Volcanic unrest and eruptions can cause considerable operational and structural challenges for the petroleum sector. The vulnerability of this sector to volcanic hazards is understudied when compared to other potentially dangerous phenomena (e.g. earthquakes). In this paper, we present new volcanic physical vulnerability models for the four key asset classes of the petroleum sector: wells, pipelines, production facilities and storage tanks. The vulnerability models are developed based on a literature review and facilitated expert judgement in the form of workshops with petroleum engineers and volcanic risk experts. These models consider four hazard intensity metrics (burial thickness, static load, dynamic pressure and airborne ash concentration) and are thus applicable to multiple volcanic hazards. We apply these models to pre-existing multi-hazard eruption scenarios for Taranaki Mounga volcano in Aotearoa New Zealand, using an available impact assessment framework to demonstrate their usability in impact and risk modelling. Our impact assessment indicates that a future eruption of Taranaki Mounga volcano could cause widespread impacts to the petroleum sector, which would in turn create a prolonged national emergency due to energy supply shortages for major industries and consumers. These vulnerability models may be applied in other volcanic regions worldwide to inform risk reduction and readiness actions.

Taranaki Mounga volcano↗

USGS2026

System characterization report on Tanager

Executive Summary This report addresses the system characterization of the Tanager satellite hyperspectral sensor created by Planet Labs PBC and is part of a series of system characterization reports produced and delivered by the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence. These reports present and detail the methodology and procedures for characterization; present technical and operational information about the Tanager hyperspectral sensor; and provide a summary of test measurements, data retention practices, data analysis results, and conclusions. This report summarizes the sensor performance of the Tanager based on the U.S. Geological Survey Earth Resources Observation and Science Cal/Val Center of Excellence system characterization process. In summary, we determined that the Tanager exhibits a band- to- band geometric error ranging from −0.074 to 0.097 pixel. Compared to the Landsat Operational Land Imager, geometric offsets ranged from −5.980 meters (−0.20 pixel) to 11.348 meters (0.40 pixel). Radiometric comparisons showed offsets between −0.004 and 0.056 with slopes from 0.830 to 1.066. Spectral shifts are found between 0.65 and 0.75 nanometers. Finally, spatial performance evaluation yielded a point spread function full width at half maximum of 1.27 to 1.75 pixels, a relative edge response of 0.802 to 0.651, and a modulation transfer function at Nyquist of 0.488 to 0.253.

Open-File Report↗

USGS2026

ECCOE Landsat quarterly calibration and validation report—Quarter 4, 2025

Executive Summary The U.S. Geological Survey Earth Resources Observation and Science Calibration and Validation (Cal/Val) Center of Excellence (ECCOE) focuses on improving the accuracy, precision, calibration, and product quality of remote-sensing data, leveraging years of multiscale optical system geometric and radiometric calibration and characterization experience. The ECCOE Landsat Cal/Val Team continually monitors the geometric and radiometric performance of active Landsat missions and makes calibration adjustments, as needed, to maintain data quality at the highest level. This report provides observed geometric and radiometric analysis results for Landsats 8 and 9 for quarter 4 (October–December) of 2025. All data used to compile the Cal/Val analysis results presented in this report are freely available from the U.S. Geological Survey EarthExplorer website: https://earthexplorer.usgs.gov . One specific activity that the ECCOE Landsat Cal/Val Team closely monitored was a Landsat 9 safehold anomaly. On October 17, 2025, Landsat 9 experienced a Solar Array Drive Assembly potentiometer fault. The onboard fault response put both the Operational Land Imager sensor and the Thermal Infrared Sensor into safe mode. Additionally, the Thermal Infrared Sensor focal plane assembly was turned off, but the cryocooler remained on. On October 20, 2025, the Solar Array Drive Assembly recovery commanding was successfully performed to put the spacecraft into nadir viewing mode. The following day, Operational Land Imager activation and recovery started, including focal plane assembly warmup. After reaching nominal operational temperatures and achieving thermal stability, science imaging resumed on October 23, 2025. Additional information about the Landsat 9 safehold anomaly is here: https://www.usgs.gov/landsat-missions/news/landsat-9-returns-normal-operations-following-brief-safehold .

Open-File Report↗

USGS2026

Tracking Pacific salmon migrations with a prototype eDNA autosampler

Pacific salmon ( Oncorhynchus spp.) are keystone species that support commercial and recreational fisheries and play a significant role in Indigenous cultures. As a keystone species, they are commonly monitored to assess population metrics and adult and juvenile migration. Environmental DNA (eDNA) has been successfully applied to salmon monitoring, but these efforts have relied on manually collected samples which can limit temporal resolution and increase field effort. Here, we evaluated a prototype autonomous eDNA sampler for fine-scale tracking of adult salmon migrations in the Lake Washington Ship Canal (LWSC) in Washington state, USA. The autosampler was deployed approximately 3 km upstream of the Ballard Locks, where returning adult salmon are counted daily, for 4 months during the adult salmon return in 2022, and it collected eDNA samples twice daily (day and night) onto self-preserving filters. We tested eDNA samples for Chinook Salmon ( Oncorhynchus tshawytscha ), Sockeye Salmon ( O. nerka ) and Coho Salmon ( O. kisutch ) and results were compared with daily adult counts at the Ballard Locks. eDNA detection lagged visual counts by approximately 5 days for Sockeye and Coho salmon and approximately 23 days for Chinook Salmon. The extensive time lag in eDNA detection for Chinook Salmon was likely due to a thermal barrier, delaying their migration through the LWSC. We found no clear effect of day versus night sampling on eDNA detection probability. Two additional experiments were performed: one to assess eDNA degradation on used self-preserving filters stored in the autosampler and another to assess whether our 3 L system flush volume was sufficient to prevent residual eDNA from being carried over from one sample to the next. We found no apparent eDNA degradation but potential for sample-to-sample carry over at this flush volume. Our study highlights the need to consider strategic placement of the autosampler intake to optimize eDNA capture and testing of flush volumes to minimize sample-to-sample carryover. Autonomous eDNA sampling provided efficient, high-frequency, and fine-scale surveillance of salmon migrations and offers a scalable approach for a wide variety of monitoring applications.

Washington↗

USGS2026

Simulating past and future refugia for temperate trees in northern Italy

During the Quaternary, trees responded to the climatic changes of glacial–interglacial cycles with large-scale range shifts. Over cold glacials, temperate tree species contracted their ranges and survived in areas known as refugia. Several studies point to the Euganean Hills (Colli Euganei), in Veneto, northern Italy, as one of the northernmost European refugia of temperate tree species during the Last Glacial Maximum (LGM, ca 23 000–19 000 calibrated years BP). Using LandClim, a spatially explicit, dynamic forest landscape model, we demonstrate that climate conditions during the LGM likely allowed temperate tree species to persist in the Euganean Hills. The identified refugial locations lie at intermediate to high elevations and in sheltered valleys within the hilly complex. Therefore, the combined palaeoecological and modelling evidence suggests that today's temperate forests of the Euganean Hills have a full glacial legacy. Simulations under future climate conditions suggest a collapse of the sub-mediterranean and oro-mediterranean deciduous forests that are prevalent today and the expansion of thermo-mediterranean evergreen forests (with e.g. Quercus ilex , Q. suber , Olea europaea and Pinus sp.). Specifically, the extrazonal population of oro-mediterranean Fagus sylvatica , which is unique to the Po Plain and likely persisted locally through several glacial–interglacial cycles, is predicted to sharply decline and face local extinction, underscoring a conservation hazard.

Ecography↗

USGS2026

Feathers and flu: Identifying data gaps in avian influenza host dynamics to prioritize wildlife conservation

Highly pathogenic avian influenza viruses (HPAIV) have had disastrous, worldwide effects on wild birds and domestic poultry since the emergence of the A/goose/Guangdong/1/1996 (Gs/GD/96) lineage. The currently circulating H5N1 clade 2.3.4.4b has an expanded set of susceptible hosts, including many migratory wild birds, and is associated with higher transmission rates, increased susceptibility among wild bird hosts, and a greater number of wildlife reservoirs. Certain wild bird life-history strategies and behaviors have been suggested to explain avian hosts’ susceptibility and exposure to HPAIV. These biological traits include gregariousness, such as colonial nesting and mixed flock foraging, predation or scavenging on wild birds, and association with aquatic habitats. Variation in host infection responses (e.g., infectability, shedding rates and duration, mortality rate, antibody development) informs the overall infection risk across avian species, yet the specific role of biological traits is often inconsistent and unclear across taxa. Moreover, the interactions and potential compounding effects among these biological traits remain largely unknown. To develop a more holistic understanding of cumulative risk across bird species, we integrate existing information on infection risk factors (i.e., susceptibility, immunological response, and behavioral traits) into a qualitative multivariate analysis. This approach enabled us to examine how infection risk factors relate to biological traits (e.g., phylogeny, physiology, behavior, species range) and to begin disentangling their complex interactions. We quantified and summarized these risk factors across host species and qualitatively ranked species by their viral responses along a proposed HPAIV response continuum, guided by expectations of traits and metrics associated with competence or vulnerability to HPAIV. In doing so, we aimed to better understand how viral responses and biological traits synergistically interact to influence cumulative risk across wild bird species. This work broadly expands on the previous avian influenza literature, which has focused on Anseriformes and Charadriiformes as primary viral reservoirs. We tie our findings to effective disease management responses with links to risk components, including descriptions of potential surveillance strategies applied to research and One Health goals, as well as a fuller understanding of how resources may be better deployed for rapid response when spillovers do inevitably occur. Additionally, we identified numerous areas where vital epidemiological information is lacking to best characterize the spread of these viruses. Ultimately, this improved understanding will help identify and inform disease management needs and decision making.

Wildlife Monographs↗

USGS2026

Spawning habitat suitability models for Lake Erie cisco (Coregonus artedi) during the historical period of pre- and post-population declines 1877–1957

Coregonine fishes play a key role in the food webs and fisheries of the Laurentian Great Lakes and are a major focus of basin-wide conservation efforts. In Lake Erie, management goals prioritize rebuilding spawning populations of cisco ( Coregonus artedi ). However, the historical distribution of cisco spawning habitat and the environmental conditions that influence early life-stage success remain poorly defined. We used a novel database of historical coregonine spawning observations as well as novel habitat variables to describe historical conditions to model and determine where and what habitat was historically most suitable for spawning cisco in Lake Erie. The environmental predictors that produced the best model included reefs, distance to rivers, historical substrate, coefficient of variation of ice duration, fetch, and circulation. The highest suitability occurred in areas of high reef probability, near river mouths, in rocky and sandy substrate, and in areas of low variability in historical ice, fetch, and circulation. Suitable spawning habitat is predicted mostly around reefs in the western basin as well as along the coast and near rivers lake-wide. Our model identifies important habitat features and allows managers to envision relevant scales and locations at which to focus restoration efforts.

Lake Erie↗

USGS2026

Dynamic coupling between faulting, rifting and magmatism during 2021-2025 unrest on Reykjanes Peninsula, Iceland

Interactions among faulting, earthquakes, and eruptions are fundamental to plate tectonics and hazard forecasting yet rarely observed along mid-ocean ridges. On Iceland's Reykjanes Peninsula, seismotectonic–volcanic unrest resumed after nearly 800-year hiatus, providing an opportunity to observe these interactions during 2021–2025 activity. By integrating high-resolution seismicity, focal mechanisms, satellite geodesy, surface deformation, and eruption data, we document ∼4 m of total extension accommodated through 14 rifting episodes. The largest, in 2023, involved graben reactivation and diking, with seismic swarms and earthquake faulting that matched the surface ruptures, where strike-slip faulting preceded normal-faulting earthquakes and extension. The accrued extension was released by extension fractures triggered by magma accumulation. Long-term observations show no correlation between erupted magma volume, seismicity, and crustal extension. This highlights dynamic relation between rifting, faulting, and magmatism in transtensional settings and their implications for hazard assessment.

Reykjanes Peninsula↗

USGS2026

Enduring cultural legacies affect Euro-American wildlife values

Social values shape biodiversity conservation success. Yet information is lacking on how values form, change and adapt people to their environment. Our 33-nation survey in 2021–2023 ( n = 18,477) explored the effect of the institutions of European colonization on present-day values towards wildlife in the Americas. Here we found mutualism values (seeing wildlife as part of one’s social community) prevail in Iberian-origin Latin American countries, whereas domination values (seeing wildlife as a resource for human use) are more prevalent in British-origin North American countries. Multilevel analysis showed significant country-level effects of colonial institution (for example, colonial origin, Protestant versus Catholic religious cultures) and endowment (for example, pre-colonial population density, Indigenous ancestry, settler mortality) factors on wildlife values in the Americas. The strong mutualism emphasis in Latin America appears to be consistent with acculturation between the compatible ideologies of Indigenous peoples and the Iberian colonizers. The effectiveness of wildlife institutions and policies will depend on their congruence with the social values of publics being served.

Nature Sustainability↗

USGS2026

Baseflow and snowmelt sustained streamflow in the Upper Colorado River Basin, 1986-2020

The Upper Colorado River Basin (UCRB) faces substantial water availability limitations. Although most streamflow originates as snowmelt, the partitioning of snowmelt between surface runoff and groundwater recharge and subsequent groundwater discharge to streams is highly uncertain. On average, over half of the streamflow in the UCRB is estimated to originate from groundwater discharge to streams, highlighting the importance of baseflow in sustaining surface water. However, the historical patterns of baseflow and streamflow, along with their variability over space and time and their specific sources, remain unknown at the basin scale. This study addresses those gaps by characterizing the sources and transport pathways of both baseflow and streamflow in the UCRB at a seasonal timestep from 1986 to 2020, including the lagged delivery of subsurface water to streams beyond the current season, using coupled models of baseflow and streamflow. Between 1986 and 2020, on average 63% of UCRB streamflow originated from baseflow. About half of this baseflow took longer than one season to reach streams, and outside the snowmelt season, baseflow was the dominant source of streamflow. Snowmelt was a key source of both baseflow and streamflow. Current season snowmelt contributed 33% of streamflow via runoff, and 22% of the 29% of streamflow that originated as current season baseflow via subsurface flow to streams. Over the study period, baseflow index (BFI) declined in headwaters and increased at mid-elevations. Springtime increases in BFI demonstrate the increasingly important role baseflow plays in water supply. Identifying the sources, locations, and timing of water that contributed to the UCRB outlet can inform management of water resources in the basin.

Arizona, Colorado, New Mexico, Utah, Wyoming↗

USGS2026

Multi-proxy thermal history of basin heating during Cordilleran orogenesis in the Magallanes-Austral retroarc foreland basin, Patagonian Andes

Resolving thermal histories in sedimentary basins is crucial for interpreting orogenic growth, basin burial, and tectonic processes during Cordilleran orogenesis. In the Magallanes–Austral Basin, Patagonian Andes, we integrate new (U-Th)/He thermochronology, vitrinite reflectance (%R o ), calcite-cement clumped isotope data and thermal history modelling to resolve the origin of the regionally extensive Paleogene unconformity (51°S–50°S). Thermal history modelling results require post-depositional heating of Palaeocene (Danian–Selandian) strata below the unconformity and suggest maximum burial temperatures of 87°C–101°C (55–52 Ma) and 89°C–92°C (18–16 Ma). For lower Eocene strata above the unconformity, Miocene burial temperatures (89°C–92°C) are consistent with calcite cement formation temperatures (~62°C–92°C) from carbonate clumped isotopes. Our results indicate that basin burial and heating between ca. 60 and 52 Ma were likely driven by shallowing of the subducting Farallon plate and enhanced plate coupling preceding arrival of the Farallon–Phoenix mid-ocean ridge. Subsequent basin inversion and cooling from ca. 52 to 44 Ma correspond with subduction of this mid-ocean ridge. Refined thermal models, constrained by expanded thermochronometric and organic maturation datasets, indicate that up to ~1.7–2.0 km of proximal foreland basin strata were removed during uplift and erosion across the Paleogene basin margin. A return to basin subsidence beginning ca. 44 Ma may reflect dynamic subsidence after passage of the mid-ocean ridge and renewed coupling between the fold-thrust belt and foreland basin system. Neogene thermal histories document continued subsidence, localized hot orogenic fluid flow along stratigraphic boundaries, followed by a final phase of basin inversion and cooling at ca. 18–16 Ma, which we attribute to regional uplift associated with Chile ridge subduction. Altogether, this study demonstrates that multiple thermal indices when analysed and modelled can provide clarity for tectonic and stratigraphic events that affect foreland basins.

Patagonian Andes↗

USGS2026

Melanoma and other melanistic lesions in brown bullhead Ameiurus nebulosus from waterbodies in the northeastern United States and Canada: Identification of risk factors

Melanistic lesions, including non-raised black areas due to proliferations of melanocytes and melanomacrophages in the dermis and epidermis, as well as raised black areas consistent with melanoma, are described in brown bullhead (BBH) Ameiurus nebulosus from three water bodies in the northeastern United States and Quebec, Canada. First observed in the Vermont portion of Lake Memphremagog, Vermont, USA and Quebec, Canada, the prevalence of melanistic lesions during 2014–2020 was greater than 30% in BBH 200 mm and longer. In 2023, seven sites throughout the lake were assessed, and prevalence ranged from 18% to 42%. In Hermon Pond, Maine, the prevalence was 29% in 2024, and in Village Pond, New Hampshire, lesions occurred in 22% of BBH in 2025. Compared to skin from visibly normal BBH, skin with melanistic lesions had significantly higher concentrations of seven metals, including arsenic, a known carcinogen and zinc. Lesions associated with oxidative damage, such as the accumulation of ceroid/lipofuscin, were also observed in the gill, spleen and kidney tissue of both affected and visibly normal BBH. The progression of lesions, observed by histopathology, ranged from inflammation, signs of oxidative damage, proliferation and necrosis of club cells, and the presence of melanomacrophages and melanocytes in the epidermis to invasive melanoma and suggests chronic exposure of BBH to environmental initiators and promoters of carcinogenesis.

New Hampshire, New York, Quebec, Vermont↗

USGS2026

Quantifying southern sea otter (Enhydra lutris nereis) reactions to a quadcopter drone in central California

Drones are useful for wildlife research and management, but they can cause disturbance and harassment to wildlife. Sea otters ( Enhydra lutris ) are candidates for drone-based observation and monitoring but are vulnerable to disturbance. No studies have evaluated drone effects on sea otter behavior, but based on prior disturbance studies, we hypothesized: (1) sea otters would exhibit behaviors indicating higher reactivity in the presence of drones than when drones were absent and (2) drone disturbance to sea otters would be greater when drones were closer. At two sites in Monterey Bay, CA, we conducted 37 observational sessions, recording behavior codes for focal sea otters during a baseline (no drone) period and three consecutive drone flights. Data were analyzed using ANOVA and ordinal logistic regression models. At both locations, focal sea otters had higher behavior codes during drone trials compared to baseline, and behavior codes increased with descending drone altitude. Pup presence, group size, flight trial number, and gull presence were significant covariables. We calculated multipliers to predict drone-mediated behavioral responses at a range of drone altitudes. Our findings can inform best practices for a variety of uses of drones around sea otters, including population monitoring, oil spill response, and drone photography/videography.

California↗

USGS2026

Unraveling protracted modification of Archean and Paleoproterozoic crust in central Laurentia, Penokean orogen, with garnet and accessory mineral geochronology and microstructural analysis

Proterozoic metamorphism and deformation of the southern margin of the Superior craton in the Lake Superior region is attributed to the Penokean orogeny (1890−1830 Ma). This model includes a period of crustal inversion in which Archean basement blocks were exhumed through overlying Paleoproterozoic strata, producing the corridor of gneiss domes that parallels the trend of the Penokean orogen across the northern Midcontinent, USA. However, recent geologic mapping and 40 Ar/ 39 Ar geochronology challenge this interpretation, suggesting instead that the gneiss dome structures reflect younger episodes of tectonic activity along the southern margin of Laurentia. In absence of integrated pressure-temperature-time-deformation constraints for these rocks, interpretations are largely limited to their final cooling history, making it difficult to both identify the tectonic forces that shaped the architecture of the Penokean orogenic belt and assess the extent to which later Proterozoic tectonism modified the southern Superior craton. We address this problem with an approach joining thermodynamic modeling, garnet and accessory mineral geochronology, and microstructural analysis for several metamorphic rocks across the gneiss dome corridor. The U-Pb ages of titanite reveal that the Proterozoic geometries of exhumed basement gneiss domes are governed by preexisting Archean structures. Garnet Lu-Hf geochronology constrains the timing of prograde-to-peak metamorphism in the Penokean orogenic belt. Granulite facies metamorphism is related to the final stages of the Penokean orogeny at 1837 Ma and localized in a belt of high-grade rocks near a major Penokean suture. Garnet Lu-Hf ages of samples adjacent to gneiss domes reflect regional metamorphism following the accretionary phase of the Penokean orogeny, between 1825 Ma and 1782 Ma, which we suggest reflects continued crustal thickening related to convergence farther south during this time interval. Combination of garnet microstructures and Sm-Nd ages reflects later exhumation of gneiss domes and buried metasedimentary rocks by ca. 1750 Ma, consistent with previously published 40 Ar/ 39 Ar cooling ages across the region. Reset Lu-Hf and Sm-Nd garnet ages and U-Pb ages of syn-kinematic titanite reflect reactivation of primary Penokean structures during this period of basement uplift. These data document significant modification of the Penokean orogen and the Archean crust of the southern Superior province between 1800 Ma and 1700 Ma. Tectonic activity during this interval coincides with collisional events recognized in western Laurentia, suggesting that the period immediately following the Penokean orogeny may be a broadly important time for crustal growth and modification in proto-North America.

Michigan, Wisconsin↗

USGS2026

Analyses of eye lens stable isotopes across ontogeny of trophically diverse freshwater salmonids

Ontogenetic niche shifts in fishes are nearly universal but remain poorly understood in many species despite being fundamentally important for the persistence, management, and conservation of fish populations, including those of vulnerable salmonids. Eye lens stable isotope analysis has proven useful in studying ontogeny in some marine species but has rarely been applied in freshwater fishes. We conducted among the first applications of eye lens stable isotope analysis in two salmonids, Arctic Charr ( Salvelinus alpinus ) and Brook Trout ( Salvelinus fontinalis ), in four North American lakes at the southern extent of the range of Arctic Charr (Maine, USA). Our goal was to determine if ontogenetic patterns varied between individuals and populations in ways that relate to differential vulnerability. Like studies in marine systems, we found patterns in lens isotopic values that agree with expected ontogenetic patterns to reach known adult trophic niches. Within lakes and individuals examined in this study, Arctic Charr appeared more dependent on pelagic resources than co-occurring Brook Trout through life. Using Bayesian hierarchical linear regressions, we found evidence that ontogenetic shifts in trophic position (measured by δ 15 N) of Arctic Charr may vary among lakes. Arctic Charr in some populations increased in trophic position through life (population lifetime δ 15 N posterior mean slope estimate = 1.01) while others showed no substantial changes (population lifetime δ 15 N posterior mean slope = 0.05), which may relate to differences in habitat and fish assemblage among our study lakes. Our study suggests that individual life stages and populations of salmonids are likely to respond to climate variability (e.g., basal resource shifts) differentially, which could warrant population and life-stage-specific management.

Maine↗

USGS2026

Continuous stream discharge, salinity, and associated data collected in the lower St. Johns River and its tributaries, Florida, 2023

The U.S. Army Corps of Engineers, Jacksonville District, deepened the St. Johns River channel in Jacksonville, Florida, to accommodate larger, fully loaded cargo vessels. The U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers, monitored stage, discharge, and (or) water temperature and salinity at 26 continuous data collection sites in the St. Johns River and its tributaries. This report contains information collected during the 2023 water year, from October 2022 to September 2023. Data at each site were compared for the length of the project, 8 years so far, and on a yearly basis to show the annual variability of discharge and salinity. The countywide annual rainfall for the 2023 water year was below the average yearly rainfall in four of the five counties. Annual mean discharge at 9 of the 10 tributary monitoring sites was lower for the 2023 water year than for the 2022 water year, and the annual mean flow at Broward River below Biscayne Boulevard near Jacksonville, Florida (USGS site number 02246751), was the lowest recorded at that site for the 8 years of data collection. The annual mean discharge for each of the main-stem sites was higher for the 2023 water year than for the 2022 water year and was above the average for the 8 years of data collected so far. Among the tributary sites, annual mean salinity was highest at Clapboard Creek above Buckhorn Bluff near Jacksonville, Fla. (USGS site number 302657081312400), the site closest to the Atlantic Ocean, and was lowest at Durbin Creek near Fruit Cove, Fla. (USGS site number 022462002), the site farthest from the ocean, for all years. Annual mean salinity data from the main-stem sites indicate that salinity decreased with distance upstream from the ocean, which was expected. Annual mean salinity for the 2023 water year was higher than or equal to that of the 2022 water year for all main-stem and tributary sites, except at St. Johns River at Dancy Point near Spuds, Fla. (USGS site number 294213081345300), which was lower. Three main-stem monitoring stations (USGS site numbers 295856081372301, 02245340, and 301057081414800) and six tributary monitoring stations (USGS site numbers 300803081354500, 022462002, 301204081434900, 02246459, 02246518, and 02246804) either had the highest annual mean salinities or tied with the highest annual mean salinities at their respective sites since data collection began.

Florida↗

USGS2026

Distribution, abundance, breeding activities, and restoration efforts for the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California—2025 Annual Report

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) and to present results of management actions implemented to attract flycatchers and enhance flycatcher habitat at Marine Corps Base Camp Pendleton (MCBCP, or Base). Surveys for the flycatcher were done on Base between May 6 and July 23, 2025. All MCBCP’s historically occupied riparian habitat (core survey area) was surveyed for flycatchers in 2025. None of the non-core survey areas were surveyed in 2025. No resident flycatchers were detected on Base in 2025. The one resident (female) present in 2024 did not return to the territory she occupied in 2024, and she was not detected within the historically occupied habitat surveyed in 2025. Eight transient Willow Flycatchers of unknown subspecies were observed on two of the five drainages surveyed in 2025: Las Flores Creek and the Santa Margarita River. No Willow Flycatchers were detected at Fallbrook, Pilgrim, or San Mateo Creeks. Transients in 2025 occurred in mixed willow and riparian scrub habitats, dominated by multiple willow species ( Salix spp. ). Exotic vegetation was recorded in most flycatcher locations and was dominant (cover of exotics greater than 50 percent) in more than half of all transient locations. The most common exotic plant in habitat used by flycatchers was poison hemlock ( Conium maculatum ). All six of the flycatchers that were observed closely enough to determine banding status were unbanded. Two measures were initiated in recent years to attract and retain resident breeding flycatchers on MCBCP: conspecific attraction using flycatcher song broadcasts and installation of artificial seeps to enhance flycatcher habitat. We surveyed plots with and without speakers that broadcast flycatcher vocalizations throughout the breeding season and detected two transient Willow Flycatchers within 20 meters of one speaker in 2025. We set up permanent vegetation sampling points surrounding artificial seeps and nearby sites without artificial seeps (Reference sites) to determine the effects of surface-water enhancement by seep pumps. Vegetation cover was highest near the ground and decreased with increasing height. Woody vegetation made up most of the cover at all height categories. Soil saturation in 2025 was higher at the sites near seeps than at the Reference sites and was associated with higher native herbaceous cover and lower non-native cover.

California↗

USGS2026

Using demographic estimation and power analysis to inform monitoring efforts and detect declines in freshwater mussels

Population assessments can be used to determine species' viability and inform conservation efforts; however, obtaining sufficient data quality and quantity can be challenging when monitoring resources are scarce. Brook Floater ( Alasmidonta varicosa ) is a freshwater mussel that is state listed in the United States as endangered or threatened in 10 of the 14 states it occupies. Despite the conservation concern, little is known about the size and demographics of most Brook Floater populations. The primary objective of this study was to determine demographic parameters (abundance and survival) for Brook Floater at five newly established, long-term monitoring sites in Maine and Massachusetts, United States. A secondary objective was to evaluate tradeoffs of potential future sampling strategies by state natural resource agencies at these monitoring sites. Mussels were sampled at each site using visual and tactile snorkel surveys twice each summer during 2018–2020 and marked with alphanumeric tags to distinguish individuals. We considered a candidate set of capture-recapture models that allowed parameters to vary depending on year, sampling occasion, and individual shell length. Abundance estimates among sites varied widely, from 29 individuals (range: 12–119) in the Nissitissit River in Massachusetts to 311 individuals (range: 307–320) in the East Branch of the Pleasant River in Maine. Annual survival was high across all sites (0.87–0.96). Given the differences in capture probability and abundance between states, we determined the statistical power available to detect given population declines in Massachusetts and explored alternative population abundance estimators in Maine. The power analysis suggested that the existing sampling regimen in Maine is likely adequate while sampling in Massachusetts may require additional occasions each year to realistically detect population declines with sufficient statistical power. This analysis demonstrates the utility of considering sampling frequency when designing capture-recapture studies for freshwater mussels and other taxa.

Maine, Massachusetts↗