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At least 1,585 records · Page 88Linked to original sources
USGS2026

Assessment of the fish tumors or other deformities beneficial use impairment and associated risks at two Lake Michigan Areas of Concern

The U.S. Great Lakes Areas of Concern (AOCs) have been designated due to significant environmental degradation, with multiple Beneficial Use Impairments (BUIs) requiring remediation before delisting. The “fish tumors or other deformities” BUI remains at the Sheboygan River and the Lower Green Bay and Fox River AOCs, necessitating evaluation in white sucker ( Catostomus commersonii ), a sentinel species. This study documented the prevalence of skin and liver neoplastic and preneoplastic lesions at these AOCs, assessed temporal trends at the Sheboygan River AOC from 2012 to 2021, and investigated potential risk factors influencing liver neoplasm development using histological and molecular approaches. Histopathological analyses revealed that skin neoplasms were present in 15.5% of fish from the Green Bay AOC and 21.5% from the Sheboygan River AOC, while liver neoplasms were detected in 7.0% and 6.0% of fish, respectively. At the Sheboygan River AOC, the prevalence of skin tumors declined from 32.6% in 2012 to 21.5% in 2021, and liver tumor prevalence decreased from 8.3% in 2012 to 6.0% in 2021. Hepatic transcript analyses identified significant expression of genes associated with contaminant exposure, oxidative stress, and immune response, suggesting ongoing exposure to environmental stressors. The presence of white sucker hepatitis B-like virus (WSHBV) in hepatocytes was confirmed, though no direct correlation between viral transcript abundance and neoplastic lesions was found. Findings indicate tumor prevalence has declined over time, however rates remain elevated compared to previous reference site assessments. The study underscores the potential multifactorial nature of carcinogenesis in wild fish populations, involving both chemical and biological stressors.

Lake Michigan↗
USGS2026

Subsurface structure across the Tacoma Basin, Washington State, using trans-dimensional Bayesian inversion of fundamental mode spatial autocorrelation data

Spatial autocorrelation (SPAC), the azimuthal average of the normalized cross-correlation between equidistant station pairs deployed in a 2-D array, is widely used to image the subsurface structure. However, the rigorous estimate of subsurface structure and its uncertainties as a function of depth using SPAC data is challenging due to the nonlinear relation between the SPAC data and Earth structure as well as the trade-off between depth and velocity. Additionally, data noise is strongly correlated due to data processing (e.g. filtering, stacking from multiple time segments and azimuthal averaging). Most studies do not account for the correlated noise and fix the ratio of compressional-wave velocity ( V P ) to shear-wave velocity ( V s ) (i.e. V P / V s ratio) and the number of layers, both of which are typically unknown. To address these challenges, we develop a hierarchical trans-dimensional Bayesian inversion of fundamental mode of SPAC data that properly accounts for the correlated data noise, samples the V P / V s ratio and relaxes the number of layers (i.e. model parametrization) to be unknown in the inversion. We further examine the limitation of using only fundamental modes in the inversion. Our synthetic experiments show that the inversion recovers an incorrect model unless we sample the correlated noise and V P / V s ratio in the inversion. The inversion is then applied to SPAC data acquired at 19 sites across the Tacoma basin in Washington State to characterize the V s and the time-averaged V s over 30-m depth ( V s 30 ). Our results show that the V s 30 varies from ∼200 to 800 m s −1 . The V s 30 within the basin is higher in the middle and lower on the east and west sides. We find that these V s 30 values vary with geologic unit. The uncertainties for V s 30 are within 20 m s −1 in average except for the most eastern site TB28. Additionally, the uncertainties are greater for deeper depths beneath most of the sites as the sensitivity decreases as a function of depth. The Vs structure as a function of depth is also complex beneath some sites, possibly because the SPAC curves are affected by higher order Rayleigh modes that are not considered in the inversion. To better constrain the deeper V s structure, V s 30 and/or other average measures of V s over depth, additional constraints from complementary data, such as ellipticity or geologic data are needed. Moreover, our synthetic experiments show that higher order modes can have significant effect in the inversion results, particularly when there is a low-velocity layer.

Washington↗
USGS2026

Rapid characterization of the 2025 Mw 8.8 Kamchatka, Russia earthquake

The 29 July 2025 M w 8.8 Kamchatka, Russia, earthquake was the sixth largest instrumentally recorded earthquake. This event was seismically well observed at regional and teleseismic distances, but publicly available near‐source data were sparse at the time of the event, presenting unique challenges for rapid source and impact characterization. The U.S. Geological Survey (USGS) National Earthquake Information Center provides global real‐time monitoring for earthquakes, including rapid response information products that estimate source characteristics, shaking, and the resulting impacts. We describe the USGS rapid response earthquake information products following the Kamchatka event and discuss their implications for ongoing hazards in the region. We describe potential improvements to our response workflows motivated by this event, including more rapid constraints on source geometries and the automated selection of fault geometries for finite‐fault inversions. The rapid response products together support the interpretation of a unilateral southwestward rupture with significant slip on the southwestern end of the rupture extent. The M w 8.8–9.0 event in 1952, which ruptured a comparable extent of the Kuril–Kamchatka subduction interface, has many similarities to the 2025 rupture. This illustrates that slip deficits may remain following great earthquakes and highlights the usefulness of comparative studies between historic and modern events.

Kuril-Kamchatka subduction zone↗
USGS2026

Complex carbonate ore mineralogy in the Mountain Pass carbonatite rare earth element deposit, USA

Economic concentrations of rare earth element (REE) minerals are uncommon in the Earth’s crust, with most occurring in carbonatites. Unlike most igneous rocks composed of silicate minerals, carbonatites are dominated by carbonate minerals, some of which can incorporate significant light REEs (LREEs; La, Ce, Pr, Nd). Technological applications of REEs are numerous and they have been identified as some of the most critical mineral commodities to the global economy. The Mountain Pass carbonatite stock in the Mojave Desert of California is the most economically significant REE deposit in the USA and contains a few to tens of percent (by volume) of the carbonate REE ore mineral bastnäsite. Despite the economic significance of the Mountain Pass deposit, studies of its ore mineralogy are limited. Here we present new carbonate ore mineralogy data for a compositionally diverse suite of carbonatitic rocks from the Mountain Pass stock and related dikes. Whole-rock geochemical data are integrated with mineral-scale textural and chemical data obtained by scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and microRaman spectroscopy. Our results document a complex spectrum of REE-bearing carbonate minerals and intermediate mixed-layer structures. Mineral species include bastnäsite [REE(CO 3 )F], hydroxylbastnäsite [REE(CO 3 )OH], parisite [Ca(REE) 2 (CO 3 ) 3 F 2 ], synchysite [Ca(REE)(CO 3 ) 2 F], röntgenite [Ca 2 (Ce,La) 3 (CO 3 ) 5 F 3 ], and sahamalite [(Mg,Fe 2+ )(REE) 2 (CO 3 ) 4 ]. Carbonate ore mineralogy is heterogeneous within and between samples, including at the intracrystal scale. Complexly zoned crystals exhibit as many as five to six different compositional domains and syntaxial intergrowths, commonly with the more Ca-rich varieties (parisite, synchysite) forming crystal rims that surround relict bastnäsite cores. We attribute the phenocryst variability to changes in the chemistry and temperature of primary carbonatite magmas and evolved/exsolved fluids. Cross-cutting vein textures of calcite, celestine and various REE carbonate minerals, interstitial bastnäsite crystallization, breccia blocks lined by fine-grained bastnäsite, and the presence of hydroxylbastnäsite and partially hydroxylated bastnäsite point to the role of secondary hydrothermal processes in REE mineralization. Fluorcarbonate mineral compositions demonstrate that La and Ce are more structurally abundant in bastnäsite, whereas the more Ca-rich species (parisite, synchysite) contain a greater proportion of REE heavier than Pr (Nd, Sm, Eu, Gd) and Y. Atomic ratios of Pr/(Nd + Pr) are likewise variable, with the highest average value for bastnäsite (0.25) compared to parisite (0.22) and sychysite (0.21). This finding has geometallurgical implications, given that current mining operations are focused on recovery of Nd and Pr for high field strength permanent magnets and the Nd/Pr ratios are a critical factor in ore processing and magnet manufacture.

California↗
USGS2026

Inventory of bat activity at Pearl Harbor National Memorial to inform historic preservation and compliance

We examined ‘ōpe‘ape‘a, or Hawaiian hoary bat ( Lasiurus semotus ; Chiroptera: Vespertilionidae), acoustic activity and surveyed potential roost trees at the Ford Island Chief Petty Officer’s (CPO) Bungalows Neighborhood of Pearl Harbor National Memorial (PERL) on the island of O‘ahu. We established four acoustic monitoring stations (PERL1–PERL4) that operated nightly to survey for ‘ōpe‘ape‘a echolocation activity from June to December 2024. Tree physiognomy data were collected at 12 potential roost trees and included tree species, tree height, diameter at breast height (DBH), percent canopy cover, distance to nearest tree, elevation, and canopy geometry. We collected 357,802 acoustic files over 672 station-nights across the four acoustic monitoring stations. ‘Ōpe‘ape‘a echolocation activity was detected over a total of 26 (4%) station-nights and during each month of the survey period except June. Echolocation activity peaked in September and October 2024, which is during the post-lactation and fledging period. These results represent a baseline for assessing ‘ōpe‘ape‘a acoustic activity and potential roosting resources in PERL.

Hawaii↗
USGS2026

Helping California get ready for when the mud hits the fan

With frequent wildfires, powerful rainstorms, steep terrain, and dense population, California is particularly vulnerable to postfire hazards like flooding and debris flow. Major postfire flooding and debris-flow events can be more costly than the fire itself, causing dozens of fatalities and widespread damage (Chawner, 1934; Lancaster et al., 2021). Smaller events occur nearly every year in California and can locally damage structures and roads, affect water quality and storage, and result in injury or loss of life (e.g., Dow et al., 2024; Rodriguez, 2025; Swanson et al., 2024; Figure 1). To mitigate these threats, the U.S. Geological Survey (USGS) has developed tools to assist local, state, and federal agencies in rapidly assessing postfire debris-flow risk across California’s diverse geology and geography. This article summarizes that effort and describes ongoing work by the USGS and partners to advance these methods and help California better prepare for future wildfires.

Caliornia↗
USGS2026

Effects of 6PPD, 6PPD-quinone, and potential alternatives on freshwater mussels.

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) is an antioxidant and antiozonant widely used in tires. When 6PPD reacts with ozone, it transforms into a breakdown product called 6PPD-quinone (6PPDQ). Both compounds are currently being studied because of their high aquatic toxicity to fish, particularly coho salmon ( Oncorhynchus kisutch ). The Washington State Legislature directed Ecology to perform an Alternatives Assessment on 6PPD in motor vehicle tires. The goal is to identify and evaluate potential replacement compounds for these products. As part of this work, Ecology is studying how potential alternatives interact with species of concern and compare those effects with what is already known about 6PPD and 6PPDQ. One of those species of concern is freshwater mussels. Freshwater mussels are an imperiled group of organisms with high cultural and ecological significance. However, there are major data gaps concerning how 6PPD affects aquatic species other than salmonids. Mussels are of particular concern due to their unique parasitic life cycle where a fish host is required to fully develop into a juvenile. If their fish host is sensitive to 6PPD, mussel populations could also be at risk. This project aims to determine lethal and sublethal toxicity of 6PPD, 6PPDQ, and any potential alternatives to freshwater mussels. This objective will be accomplished by conducting acute toxicity tests with the compounds to determine median lethal concentrations (LC 50 s) of the tested compounds to freshwater mussels. Sublethal toxicity will be studied by then determining if the presence of 6PPD, 6PPDQ, and potential alternatives impacts the mussel’s ability to use a fish host for the important parasitic stage of its life cycle.

Washington↗
USGS2026

Integrating climate and anthropogenic dynamics can inform multifaceted management for declining mule deer populations

Wildlife and their habitats face profound challenges from climate and landscape-scale changes that extend beyond the influence and time horizon of most biologists and land managers. In this changing environment, long-term datasets can enhance assessments of how demographic trends respond to interactions among local (e.g., habitat restoration decisions) and broad extent drivers, including energy development, to shape wildlife populations. Although many studies evaluate habitat selection or demographics for a single population, our multipopulation, multiscale study quantifies the influence of local management actions given broader environmental forces using both immediate and lagged effects. This approach may be particularly important for species with high site fidelity that may have less adaptive capacity, including mule deer ( Odocoileus hemionus ), which are experiencing widespread population declines. We analyzed a 40-year (1980–2019) dataset for 37 mule deer populations across Wyoming, USA, to test hypotheses about and quantify the relative influence of conditions within winter use areas on annual rates of juvenile recruitment. Recruitment has been strongly affected by multiple factors largely beyond the control of managers. Land cover (agriculture and shrubland) had the largest positive effects on recruitment, with estimates more than twice the magnitude of other variables, but also had limited presence in some winter use areas. The next strongest effect sizes were shared by energy developments (including oil/gas and wind energy) and climatic conditions, which, except for wind turbines, had broad distributions across winter use areas. Recruitment increased with higher mean winter temperatures and summer precipitation, but declined with wind, oil and gas developments, cumulative drought, and wildfire. Expected increases in drought and decreases in summer precipitation may constrain options to sustain mule deer populations. Although mule deer recruitment may sometimes be enhanced through habitat restoration, effects varied with treatment type, habitat type, and time since treatment. Given large constraining effects of temperature and drought, supporting drought resiliency for important habitat may be useful. Our results can be used to weigh the relative strength of threats and the value of restoration actions, interpret historic demographic change, prioritize populations for conservation, and optimize options for wildlife habitat management.

Wyoming↗
USGS2026

Reservoir cascades as directional invasion corridors

Reservoir cascades in large river systems impose directional pathways that can structure biological invasions, yet how these pathways interact with propagule supply and lock-mediated passage opportunity to influence arrival timing remains poorly understood. We used interval- and right-censored time-to-event models to evaluate spread dynamics of silver carp ( Hypophthalmichthys molitrix ) across the Tennessee River and Cumberland River reservoir cascades and test whether the timing of first detection was explained by position within the cascade, annual water locked, or accumulated propagule exposure from downstream source populations. The timing of first detection was related to distance from the invasion source, but cumulative exposure metrics offered no supplementary model support, suggesting that arrival timing was mostly associated with position within the cascade. Models incorporating annual water locked offered modest supplementary support, suggesting that lock-mediated passage opportunity may partially influence the progression of the invasion front. Spread progressed directionally but was not complete in the Tennessee River cascade, indicating that pathway structure alone does not guarantee arrival. Patterns were consistent across both rivers, suggesting that spread through reservoir cascades can follow repeatable patterns in which arrivals are constrained by downstream source populations and lock-mediated connectivity. From a management perspective, our results suggest distinct leverage points across spatial and temporal scales, including early detection and containment at downstream reservoirs, suppression of source populations to slow spread, and interventions at invasion fronts or key connectivity points to limit further expansion. Recognizing reservoir cascades as directional dispersal pathways provides a simple and transferable basis for anticipating and managing invasions in large river networks.

Tennessee↗
USGS2026

Hazards related to man-made structures: Buildings, noise, electric power

Many man-made structures can form a hazard to avian wildlife. The most common hazard is one of collision, and this paper will look at problems with glass in buildings, power lines, and wind turbines all as sources of collision and trauma to avian wildlife. However, other anthropogenic factors that can adversely affect avian wildlife can be those that effectively eliminate suitable habitat for avian wildlife. These can include noise factors associated with such things as wind turbines and construction areas and the loss of habitat to large solar arrays, not to mention strip mining for coal and oil-sands. All these factors can contribute to the estimated loss of 3 billion birds in the last five decades.

Book chapter↗
USGS2026

Archean to Mesozoic–Cenozoic seismic crustal structure: Implications for geological and biological evolution

We use >4500 measurements of crustal structure to investigate the seismic structure of continental crust, Archean to Mesozoic–Cenozoic. The mean crustal thickness of continents, including their margins, is 36.5 km. We find that Archean, Paleoproterozoic, and Mesoproterozoic crust have similar mean crustal thickness (41 km), seismic velocities, Vp/Vs ratio, and density. Crusts of these ages span 3 Ga, from 4.0 to 1.0 Ga, and their similarity of physical properties (thickness, density, and seismic velocities) suggests that the process of crustal formation may have been similar during this time period, which covers 66% of Earth's history. Neoproterozoic crustal properties differ significantly from Mesoproterozoic and older crusts. The mean thickness of Neoproterozoic crust is 32 km, some 9 km thinner than the mean thickness of Archean, Paleoproterozoic, and Mesoproterozoic crust. A lithospheric root with a thickness of 150–200 km underlies Archean, Paleoproterozoic, and Mesoproterozoic crusts, and this root resists lithospheric rifting and crustal extension and thinning. Based on these observations, particularly the lithospheric thickness, we conclude that Archean, Paleoproterozoic, and Mesoproterozoic lithosphere are unique and together form the stable cratonic nuclei, defined as the thick (150–250 km), long-lived cores of continents. Higher mantle temperatures during the Archean, Paleoproterozoic, and Mesoproterozoic may have played a key role in the formation of the thick lithospheric roots. The second key finding is that the similarities of mean seismic properties indicate that the process of crustal formation operating in the Archean continued during the Paleoproterozoic and Mesoproterozoic. The thin (mean value < 135 km) lithospheric root beneath Neoproterozoic and younger crust may be related to the steady decrease in mantle temperature through time. Neoproterozoic and Paleozoic crust have similar physical properties, and these eras are characterized by pronounced biodiversification, including the renowned Garden of Ediacara, the Cambrian Explosion, and the Great Ordovician Biodiversification. Mesozoic–Cenozoic crust is the most diverse and reflects the current tectonic and magmatic processes of crustal formation.

Book chapter↗
USGS2026

Using quantitative polymerase chain reaction to assess phytoplankton and indicate eutrophication in freshwater rivers: A multiyear nationwide study across the United States

Phytoplankton are essential primary producers in fresh surface water that are critical to the health of ecosystems. However, phytoplankton overgrowth due to eutrophication threatens ecological, economic, and public health. Therefore, assessing phytoplankton is fundamental for understanding the productivity, health, and trophic status of freshwater ecosystems. Light microscopy and chlorophyll a assessment are common approaches for studying phytoplankton. They are easy to use, cost-effective, and reliable but have significant limitations. Microscopy has a low throughput and is time-consuming and labor-intensive. Chlorophyll a assessment does not reveal phytoplankton community composition and structure. For comparison, quantitative polymerase chain reaction (qPCR) is widely applied in quantifying microorganisms, offering multiple advantages, including high throughput, sensitivity, accuracy, and robustness. However, a research gap remains regarding the feasibility of using qPCR to assess phytoplankton and indicate trophic status of freshwater bodies. We conducted a nationwide, multiyear study in the United States to compare the performance of qPCR, microscopy, and chlorophyll a assessment in assessing phytoplankton and trophic statuses of multiple freshwater rivers. From early summer to late fall in 2017, 2018, and 2019, we assessed phytoplankton, chlorophyll a , pheophytin a , and the overall Trophic Level Index ( TLI Overall ) at the sampling sites in 12 large freshwater rivers in three regions (western, midcontinent, and eastern) across the United States. The seasonal summed abundance of four major phytoplankton taxa [Bacillariophyta (diatoms), Cyanobacteria (blue-green algae), Chlorophyta (green algae), and Dinoflagellates (Dinophyta)] ranged from 6.88 log 10 (GCN·L –1 ) (the Connecticut River, 2017) to 9.29 log 10 (GCN·L –1 ) (the Kansas River, 2019) (GCN: gene or genome copy number). qPCR- and microscopy-based phytoplankton abundance of eight phytoplankton taxa had a significant positive allometric or log-linear correlation (adjusted R 2 = 0.836, p -value < 0.001, n = 815). In addition, qPCR-based phytoplankton abundance had positive allometric or log-linear correlations with chlorophyll a (adjusted R 2 = 0.5437, p -value < 0.001, n = 164), pheophytin a (adjusted R 2 = 0.3378, p -value < 0.001, n = 164), and TLI Overall (adjusted R 2 = 0.4789, p -value < 0.001, n = 164). Therefore, qPCR is a promising alternative to microscopy and chlorophyll a for studying phytoplankton and trophic status in freshwater rivers. Moreover, phytoplankton abundance had limited temporal variation within each sampling season and over the three sampling seasons in 2017, 2018, and 2019 but showed clear spatial variation. The midcontinent sites had significantly higher phytoplankton abundance, chlorophyll a concentrations, pheophytin a concentrations, and TLI Overall values than those in the eastern and western rivers, reflecting the higher trophic statuses of the midcontinent rivers. This work also provides the thresholds of qPCR-based phytoplankton abundance for delineating trophic statuses in freshwater rivers. Overall, this work demonstrates that qPCR is a promising tool for studying phytoplankton and characterizing the trophic status of freshwater rivers.

Book chapter↗
USGS2026

Quantifying the subfield heterogeneity in winter cereal cover crop biomass across farms in the Mid-Atlantic Coastal Plain

Winter cover crops can reduce erosion and improve water quality. Ecosystem services generally increase with higher cover crop biomass, but they are known to be variable within the field. We generated a large remotely-sensed biomass dataset from more than 8,000 fields enrolled in a cover crop cost share program to study biomass heterogeneity from fields in the Choptank and Chester-Sassafras watersheds in the Delmarva Peninsula, across four years. We also used soil and topography data to determine drivers of subfield heterogeneity in cover crop biomass. We found that winter cover crop biomass heterogeneity is higher in fields with large cover crops, and that low-lying or poorly-drained positions on the landscape often had lower biomass in the most variable fields. Random forest model performance at predicting subfield cover crop biomass was slightly improved at 9 m compared to 3 m spatial resolution. We demonstrate that remotely-sensed normalized difference vegetation index, soil, and topography data can be used to quantify variation in cover crop biomass at a watershed scale.

Maryland↗
USGS2026

Erosion and transport of sediments in watersheds of southwest Puerto Rico determined from strontium isotopes and mixing models

Sediment outflow from streams to coastal regions can adversely affect water quality and the health of ecosystems including Puerto Rico's southwestern carbonate platform with shallow marine communities. Knowledge of sediment provenance and erosional areas would aid effective restoration to reduce excessive sedimentation. Strontium (Sr) isotopic ratios ( 87 Sr/ 86 Sr) can be used to differentiate between sediment eroded into streams from different lithologies, or rock types, and used in mixing models to estimate proportions of source materials in downstream mixtures. The goal of this study was to use Sr isotopes to differentiate between river sediments in drainages with distinct geologies and present a case study where Sr isotope mixing models are used to identify sediment sourcing to Río Loco and Bahía de Guánica, a priority watershed of the U.S. Coral Reefs Task Force. For the Río Loco watershed, model results indicate that serpentinites in the uplands contributed approximately 71 % of sediment to Bahía de Guánica. About 21 % of sediment was from trachy-andesitic basalts in the foothills, and the remaining 8 % originated from sources on the coastal plain. Neither the uppermost headwater region of Río Loco, the Canal Principal De Riego Valle De Lajas, nor the tributary Quebrada Susúa appeared to be significant sources of sediment to Río Loco's mainstem or Bahía de Guánica at the time of the study. Our results demonstrate that sediment from the serpentinite-bearing areas of Río Loco watershed was effectively transported to the lowlands, which then discharge into Guánica Bay, and highlight the potential use of Sr isotopes as tracers of sediment provenance. This will, in turn, enable better science-based restoration efforts aimed at reducing terrestrial sediment erosion and impacts to marine ecosystems.

Puerto Rico↗
USGS2026

PFAS exposure suppresses leaf litter decomposition in a stream ecosystem

Decomposition of organic matter is critical to the biogeochemical cycling of carbon and nutrients in all ecosystems. In streams, decomposition can be influenced by anthropogenic impacts, including contaminants. Per- and polyfluoroalkyl substances (PFAS) are resistant to degradation and widespread in freshwater ecosystems, yet little is known about their influence on organic matter processing in streams. We paired an observational field study of a PFAS-impacted stream via food processing wastewater with a 28-day laboratory experiment to investigate PFAS effects on leaf litter processing using multiple lines of evidence. Leaf litter decomposition rates and microbial respiration were significantly lower downstream of the PFAS point-source compared to the paired upstream site. We hypothesized that PFAS suppressed microbial activity thereby resulting in slower decomposition rates. To investigate further and better isolate PFAS, we dosed aquatic mesocosms containing leaf packs with differing concentrations of perfluorooctane sulfonate (PFOS). Over the 28-day incubation, decomposition rates did not differ, but we observed lower respiration rates on day 28 and higher dissolved organic carbon (DOC) in PFOS-dosed mesocosms, suggesting that PFAS may suppress microbial activity and inhibit carbon processing. These results underscore that concerns regarding PFAS contamination extend beyond organismal toxicity to ecosystem-level effects. Further research is needed to understand the scale, implications, and mechanisms responsible for these changes.

Upper Mississippi River Basin↗
USGS2026

Global change and threats to waterbirds in the Asian flyways

Avian migration represents one of nature’s most spectacular phenomena, providing critical ecological services and acting as an indicator of environmental change. Flyways are geographical ranges through which migrating bird species move, and the flyway concept has been used to identify countries that share species to highlight their collective responsibility for conservation. Of the nine recognized global waterbird flyways, the Central Asian Flyway (CAF) and the East Asian–Australasian Flyway (EAAF) are among the most important areas in Eurasia, supporting millions of waterbirds across a vast network of habitats. We proposed this special issue in Avian Research entitled “Global Change and Threats to Waterbirds in the Asian Flyways” to synthesize recent findings from 12 papers covering a wide range of topics. The CAF stretches from the Siberian tundra through Central Asia including Mongolia, the Qinghai-Tibet Plateau, the Trans-Caucasus, and the Himalayas, extending south to the Indian subcontinent and parts of the Middle East. The EAAF spans eastern Siberia and Alaska to Southeast Asia, Australia, and New Zealand, including China, Japan, the Korean Peninsula, and the Russian Far East. These two flyways include 47 countries comprising critical wetlands, river basins, and coastal areas, which are vital breeding, stopover, and wintering grounds for waterbirds. Seasonal migration in these flyways is fundamentally influenced by climate and weather conditions, land cover dynamics, and anthropogenic activities, and contributes significantly to ecological processes such as pest control, nutrient cycling, and organism dispersal. However, migratory waterbirds and their habitats are undergoing enormous challenges. Changes in climate, habitat availability and connectivity, and human activities are altering the phenology, distribution, population dynamics, and health of the migratory bird populations. As migratory waterbirds travel across international boundaries, understanding their movements and responses to environmental change requires collaborative, cross-border research efforts that promote knowledge sharing and interdisciplinary approaches.

Avian Research↗
USGS2026

Wildfire smoke reduces the vocal activity of imperiled grassland birds in New York State

Smoke from new fire regimes driven by climate change may affect biodiversity in new regions of the world. Wildfires that occurred in eastern Canada in 2023 burned nearly 7.8 million hectares of forest, sending smoke throughout the northeastern United States. We leveraged passive acoustic monitoring to investigate real-time effects of wildfire smoke on vocalization behavior of globally imperiled grassland birds during the breeding season in open land covers across New York State. We determined an overall negative effect of elevated smoke levels on breeding grassland bird vocal activity. We observed the strongest vocalization responses in Bobolink ( Dolichonyx oryzivorus ) – a colonial breeding, grassland-obligate species; Bobolink vocal activity sharply dropped during intense smoke early in the breeding season, yet increased during a milder smoke event later in the breeding season. Our results indicate that wildfire smoke can present an additive stressor to already imperiled grassland bird species via potential fitness reductions from decreased communication. While some aspects of smoke exposure may be uncontrollable, our results suggest that increased attention to conservation practices that promote grassland birds in the Northeast could be prioritized to offset negative effects of increased smoke associated with global change.

New York↗