SEARCH · USGS Science

Results for “Community Science”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources

USGS2024

Improving ecosystem health in highly altered river basins: A generalized framework and its application to the Mississippi-Atchafalaya River Basin

Continued large-scale public investment in declining ecosystems depends on demonstrations of “success”. While the public conception of “success” often focuses on restoration to a pre-disturbance condition, the scientific community is more likely to measure success in terms of improved ecosystem health. Using a combination of literature review, workshops and expert solicitation we propose a generalized framework to improve ecosystem health in highly altered river basins by reducing ecosystem stressors, enhancing ecosystem processes and increasing ecosystem resilience. We illustrate the use of this framework in the Mississippi-Atchafalaya River Basin (MARB) of the central United States (U.S.), by (i) identifying key stressors related to human activities, and (ii) creating a conceptual ecosystem model relating those stressors to effects on ecosystem structure and processes. As a result of our analysis, we identify a set of landscape-level indicators of ecosystem health, emphasizing leading indicators of stressor removal (e.g., reduced anthropogenic nutrient inputs), increased ecosystem function (e.g., increased water storage in the landscape) and increased resilience (e.g., changes in the percentage of perennial vegetative cover). We suggest that by including these indicators, along with lagging indicators such as direct measurements of water quality, stakeholders will be better able to assess the effectiveness of management actions. For example, if both leading and lagging indicators show improvement over time, then management actions are on track to attain desired ecosystem condition. If, however, leading indicators are not improving or even declining, then fundamental challenges to ecosystem health remain to be addressed and failure to address these will ultimately lead to declines in lagging indicators such as water quality. Although our model and indicators are specific to the MARB, we believe that the generalized framework and the process of model and indicator development will be valuable in an array of altered river basins.

Mississippi-Atchafalaya River Basin↗

USGS2012

A brief history and summary of the effects of river engineering and dams on the Mississippi River system and delta

The U.S. Geological Survey Forecast Mekong project is providing technical assistance and information to aid management decisions and build science capacity of institutions in the Mekong River Basin. A component of this effort is to produce a synthesis of the effects of dams and other engineering structures on large-river hydrology, sediment transport, geomorphology, ecology, water quality, and deltaic systems. The Mississippi River Basin (MRB) of the United States was used as the backdrop and context for this synthesis because it is a continental scale river system with a total annual water discharge proportional to the Mekong River, has been highly engineered over the past two centuries, and the effects of engineering have been widely studied and documented by scientists and engineers. The MRB is controlled and regulated by dams and river-engineering structures. These modifications have resulted in multiple benefits including navigation, flood control, hydropower, bank stabilization, and recreation. Dams and other river-engineering structures in the MRB have afforded the United States substantial socioeconomic benefits; however, these benefits also have transformed the hydrologic, sediment transport, geomorphic, water-quality, and ecologic characteristics of the river and its delta. Large dams on the middle Missouri River have substantially reduced the magnitude of peak floods, increased base discharges, and reduced the overall variability of intraannual discharges. The extensive system of levees and wing dikes throughout the MRB, although providing protection from intermediate magnitude floods, have reduced overall channel capacity and increased flood stage by up to 4 meters for higher magnitude floods. Prior to major river engineering, the estimated average annual sediment yield of the Mississippi River Basin was approximately 400 million metric tons. The construction of large main-channel reservoirs on the Missouri and Arkansas Rivers, sedimentation in dike fields, and protection of channel banks by revetments throughout the basin, have reduced the overall sediment yield of the MRB by more than 60 percent. The primary alterations to channel morphology by dams and other engineering projects have been (1) channel simplification and reduced dynamism; (2) lowering of channel-bed elevation; and (3) disconnection of the river channel from the flood plain, except during extreme flood events. Freshwater discharge from the Mississippi River and its associated sediment and nutrient loads strongly influence the physical and biological components in the northern Gulf of Mexico. Ninety percent of the nitrogen load reaching the Gulf of Mexico is from nonpoint sources with about 60 percent coming from fertilizer and mineralized soil nitrogen. Much of the phosphorus is from animal manure from pasture and rangelands followed by fertilizer applied to corn and soybeans. Increased nutrient enrichment in the northern Gulf of Mexico has resulted in the degradation of water quality as more phytoplankton grow, which increases turbidity and depletes oxygen in the lower depths creating what is known as the "dead zone." In 2002, the dead zone was 22,000 square kilometers (km2), an area similar to the size of the State of Massachusetts. Changes in the flow regime from engineered structures have had direct and indirect effects on the fish communities. The navigation pools in the upper Mississippi River have aged, and these overwintering habitats, which were created when the pools filled, have declined as sedimentation reduces water depth. Reproduction of paddlefish may have been adversely affected by dams, which impede access to suitable spawning habitats. Fishes that inhabit swift-current habitats in the unimpounded lower Mississippi River have not declined as much as in the upper Mississippi River. The decline of the pallid sturgeon may be attributable to channelization of the Missouri River above St. Louis, Missouri. The Missouri River supports a rich fish community and remains relatively intact. Nevertheless, the widespread and long history of human intervention in river discharge has contributed to the declines of about 25 percent of the species. The Mississippi River Delta Plain is built from six delta complexes composed of a massive area of coastal wetlands that support the largest commercial fishery in the conterminous United States. Since the early 20th century, approximately 4,900 km2 of coastal lands have been lost in Louisiana. One of the primary mechanisms of wetland loss on the Plaquemines-Balize complex is believed to be the disconnection of the river distributary network from the delta plain by the massive system of levees on the delta top, which prevent overbank flooding and replenishment of the delta top by sediment and nutrient deliveries. Efforts by Federal and State agencies to conserve and restore the Mississippi River Delta Plain began over three decades ago and have accelerated over the past decade. Regardless of these efforts, however, land losses are expected to continue because the reduced upstream sediment supplies are not sufficient to keep up with the projected depositional space being created by the combined forces of delta plain subsidence and global sea-level rise.

Alabama;Alberta;Arkansas;Colorado;Georgia;Illinois↗

USGS2021

Impacts of a non-indigenous ecosystem engineer, the American beaver (Castor canadensis), in a biodiversity hotspot

Non-native species having high per capita impacts in invaded communities are those that modulate resource availability and alter disturbance regimes in ways that are biologically incompatible with the native biota. In areas where it has been introduced by humans, American beaver ( Castor canadensis ) is an iconic example of such species due to its capacity to alter trophic dynamics of entire ecosystems and create new invasional pathways for other non-native species. The species is problematic in several watersheds within the Southern California-Northern Baja California Coast Ecoregion, a recognized hotspot of biodiversity, due to its ability to modify habitat in ways that favor invasive predators and competitors over the region's native species and habitat. Beaver was deliberately introduced across California in the mid-1900s and generally accepted as non-native to the region up to the early 2000s; however, articles promoting the idea that beaver may be a natural resident have gained traction in recent years, due in large part to the species' charismatic nature rather than by presentation of sound evidence. Here, we discuss the problems associated with beaver disturbance and its effects on conserving the region's native fauna and flora. We refute arguments underlying the claim that beaver is native to the region, and review paleontological, zooarchaeological, and historical survey data from renowned field biologists and naturalists over the past ~160 years to show that no evidence exists that beaver arrived by any means other than deliberate human introduction. Managing this ecosystem engineer has potential to reduce the richness and abundance of other non-native species because the novel, engineered habitat now supporting these species would diminish in beaver-occupied watersheds. At the same time, hydrologic functionality would shift toward more natural, ephemeral conditions that favor the regions' native species while suppressing the dominance of the most insidious invaders.

California↗

USGS2016

Mercury in western North America: A synthesis of environmental contamination, fluxes, bioaccumulation, and risk to fish and wildlife

Western North America is a region defined by extreme gradients in geomorphology and climate, which support a diverse array of ecological communities and natural resources. The region also has extreme gradients in mercury (Hg) contamination due to a broad distribution of inorganic Hg sources. These diverse Hg sources and a varied landscape create a unique and complex mosaic of ecological risk from Hg impairment associated with differential methylmercury (MeHg) production and bioaccumulation. Understanding the landscape-scale variation in the magnitude and relative importance of processes associated with Hg transport, methylation, and MeHg bioaccumulation requires a multidisciplinary synthesis that transcends small-scale variability. The Western North America Mercury Synthesis compiled, analyzed, and interpreted spatial and temporal patterns and drivers of Hg and MeHg in air, soil, vegetation, sediments, fish, and wildlife across western North America. This collaboration evaluated the potential risk from Hg to fish, and wildlife health, human exposure, and examined resource management activities that influenced the risk of Hg contamination. This paper integrates the key information presented across the individual papers that comprise the synthesis. The compiled information indicates that Hg contamination is widespread, but heterogeneous, across western North America. The storage and transport of inorganic Hg across landscape gradients are largely regulated by climate and land-cover factors such as plant productivity and precipitation. Importantly, there was a striking lack of concordance between pools and sources of inorganic Hg, and MeHg in aquatic food webs. Additionally, water management had a widespread influence on MeHg bioaccumulation in aquatic ecosystems, whereas mining impacts where relatively localized. These results highlight the decoupling of inorganic Hg sources with MeHg production and bioaccumulation. Together the findings indicate that developing efforts to control MeHg production in the West may be particularly beneficial for reducing food web exposure instead of efforts to simply control inorganic Hg sources.

Science of the Total Environment↗

USGS2023

Contribution of arsenic and uranium in private wells and community water systems to urinary biomarkers in US adults: The Strong Heart Study and the Multi-Ethnic Study of Atherosclerosis

Background Chronic exposure to inorganic arsenic (As) and uranium (U) in the United States (US) occurs from unregulated private wells and federally regulated community water systems (CWSs). The contribution of water to total exposure is assumed to be low when water As and U concentrations are low. Objective We examined the contribution of water As and U to urinary biomarkers in the Strong Heart Family Study (SHFS), a prospective study of American Indian communities, and the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective study of racially/ethnically diverse urban U.S. communities. Methods We assigned residential zip code-level estimates in CWSs (µg/L) and private wells (90th percentile probability of As >10 µg/L) to up to 1485 and 6722 participants with dietary information and urinary biomarkers in the SHFS (2001–2003) and MESA (2000–2002; 2010–2011), respectively. Urine As was estimated as the sum of inorganic and methylated species, and urine U was total uranium. We used linear mixed-effects models to account for participant clustering and removed the effect of dietary sources via regression adjustment. Results The median (interquartile range) urine As was 5.32 (3.29, 8.53) and 6.32 (3.34, 12.48) µg/L for SHFS and MESA, respectively, and urine U was 0.037 (0.014, 0.071) and 0.007 (0.003, 0.018) µg/L. In a meta-analysis across both studies, urine As was 11% (95% CI: 3, 20%) higher and urine U was 35% (5, 73%) higher per twofold higher CWS As and U, respectively. In the SHFS, zip-code level factors such as private well and CWS As contributed 46% of variation in urine As, while in MESA, zip-code level factors, e.g., CWS As and U, contribute 30 and 49% of variation in urine As and U, respectively. Impact statement We found that water from unregulated private wells and regulated CWSs is a major contributor to urinary As and U (an estimated measure of internal dose) in both rural, American Indian populations and urban, racially/ethnically diverse populations nationwide, even at levels below the current regulatory standard. Our findings indicate that additional drinking water interventions, regulations, and policies can have a major impact on reducing total exposures to As and U, which are linked to adverse health effects even at low levels.

Journal of Exposure Science and Environmental Epid↗

USGS2020

Evaluation of EPT macroinvertebrate metrics in small streams located within the non-connected stormwater management region of Kansas City, Missouri, USA

During 2012-2014, we evaluated macroinvertebrate communities in streams draining the non-connected stormwater management region (Municipal Separate Storm Sewer System, or MS4) within the Kansas City metropolitan area utilizing the Missouri bioassessment protocols. Trends in aquatic life impairment status based on Missouri's Macroinvertebrate Stream Condition Index (MSCI), as well as richness and abundance of EPT indicator metrics (Ephemeroptera, Plecoptera, Trichoptera), were compared between rural control sites and both transitional and urban stream sites representing varying stages of land use conversion. As compared to non-urban control sites, EPT taxa richness was significantly lower at MS4 urban sites during all three years (p = 0.007 – 0.013) and MS4 transitional sites during one of three years (p=0.48). EPT abundance (%) was significantly lower at MS4 urban sites during all years (p = 0.008 – 0.013) and MS4 transitional sites during one of three years (p=0.34). Mean EPT abundances ranged between 0.6% - 10.3% at urban MS4 sites, and always exceeded 18% at control sites. Both EPT richness and abundance were lower at the MS4 control site but means for EPT and other core metrics at this site were most often similar to non-urban control sites based on analysis of variance (ANOVA). MS4 transitional sites with active development in their watersheds were partially-supporting in their impairment status, and EPT metrics had lower means and generally more variability than control sites. Temporal trends indicate non-urban control and MS4 control sites consistently meet fully-supporting impairment status based on overall MSCI scores, but no study sites currently meet regional expectations (as defined by state reference streams) for either of the EPT metrics. Results indicate that Missouri and Kansas biocriteria for both EPT metrics are not consistently being met at any stream sites in the Kansas City metro area, including fully-supporting control sites and MS4 streams that receive stormwater runoff in watersheds with urban development that is well-established or currently transitioning to urban or suburban land uses.

Missouri↗

USGS2020

Accurate bathymetric maps from underwater digital imagery without ground control

Structure-from-Motion (SfM) photogrammetry can be used with digital underwater photographs to generate high-resolution bathymetry and orthomosaics with millimeter-to-centimeter scale resolution at relatively low cost. Although these products are useful for assessing species diversity and health, they have additional utility for quantifying benthic community structure, such as coral growth and fine-scale elevation change over time, if accurate length scales and georeferencing are included. This georeferencing is commonly provided with “ground control,” such as pre-installed seafloor benchmarks or identifiable “static” features, which can be difficult and time consuming to install, survey, and maintain. To address these challenges, we developed the SfM Quantitative Underwater Imaging Device with Five Cameras (SQUID-5), a towed surface vehicle with an onboard survey-grade Global Navigation Satellite System (GNSS) and five rigidly mounted downward-looking cameras with overlapping views of the seafloor. The cameras are tightly synchronized with both the GNSS and each other to collect quintet photo sets and record the precise location of every collection event. The system was field tested in July 2019 in the U.S. Florida Keys, in water depths ranging from 3 to 9 m over a variety of bottom types. Surveying accuracy was assessed using pre-installed stations with known coordinates, machined scale bars, and two independent surveys of a site to evaluate repeatability. Under a range of sea conditions, ambient lighting, and water clarity, we were able to map living and senile coral reef habitats and sand waves at mm-scale resolution. Data were processed using best practice SfM techniques without ground control and local measurement errors of horizontal and vertical scales were consistently sub-millimeter, equivalent to 0.013% RMSE relative to water depth. Survey-to-survey repeatability RMSE was on the order of 3 cm without georeferencing but could be improved to several millimeters with the incorporation of one or more non-surveyed marker points. We demonstrate that the SQUID-5 platform can map complex coral reef and other seafloor habitats and measure mm-to-cm scale changes in the morphology and location of seafloor features over time without pre-existing ground control.

Florida↗

USGS2021

Improved wetland soil organic carbon stocks of the conterminous U.S. through data harmonization

Wetland soil stocks are important global repositories of carbon (C) but are difficult to quantify and model due to varying sampling protocols, and geomorphic/spatio-temporal discontinuity. Merging scales of soil-survey spatial extents with wetland-specific point-based data offers an explicit, empirical and updatable improvement for regional and continental scale soil C stock assessments. Agency-collected (U.S. Department of Agriculture, U.S. Environmental Protection Agency) and community-contributed soil datasets were compared for representativeness and bias, with the goal of producing a harmonized national map of wetland soil C stocks with error quantification for wetland areas of the conterminous United States (CONUS) identified by the USGS National Landcover Change Dataset (NLCD). This allowed application of an empirical predictive model of SOC density to be applied across the entire CONUS using relational %OC distribution alone. A broken-stick quantile-regression model identified %OC with its relatively high analytical confidence as a key predictor of SOC density in soil segments; soils less than 6%OC (hereafter, mineral wetland soils, 85% of the dataset) had a strong linear relationship of %OC to SOC density (RMSE = 0.0059, ~4% mean RMSE) and soils greater than 6%OC (organic wetland soils, 15% of the dataset) had virtually no predictive relationship of %OC to SOC density (RMSE = 0.0348 g C cm-3, ~56% mean RMSE). Disaggregation by vegetation type (woody v. emergent herbaceous), or region did not alter the breakpoint significantly (6% OC) nor improve model accuracies for inland and tidal wetlands. Similarly, SOC stocks in tidal wetlands were related to %OC, but without a mappable product for disaggregation to improve accuracy by soil class, region or depth. Our layered, harmonized CONUS wetland soil maps have now revised wetland SOC stock estimates downward by 24% (9.5 vs. 12.5Pg C) with the overestimation being entirely an issue of inland, organic wetland soils, (35% lower than SSURGO-derived SOC stocks). Further, SSURGO underestimated soil carbon stocks at depth, as modeled wetland SOC stocks for organic-rich soils showed significant preservation downcore in the NWCA dataset (<3% loss between 0-30 cm and 30-100 cm depths) in contrast to mineral-rich soils (37% downcore stock loss). Future CONUS wetland soil C assessments will benefit from focused attention on improved organic wetland soil measurements, land history, and spatial representativeness.

Frontiers in Soil Science↗

USGS2020

Simulated estuary-wide response of seagrass (Zostera marina) to future scenarios of temperature and sea level

Seagrass communities are a vital component of estuarine ecosystems, but are threatened by projected sea level rise (SLR) and temperature increases with climate change. To understand these potential effects, we developed a spatially explicit model that represents seagrass ( Zostera marina ) habitat and estuary-wide productivity for Barnegat Bay-Little Egg Harbor (BB-LEH) in New Jersey, United States. Our modeling approach included an offline coupling of a numerical seagrass biomass model with the spatially variable environmental conditions from a hydrodynamic model to calculate above and belowground biomass at each grid cell of the hydrodynamic model domain. Once calibrated to represent present day seagrass habitat and estuary-wide annual productivity, we applied combinations of increasing air temperature and sea level following regionally specific climate change projections, enabling analysis of the individual and combined impacts of these variables on seagrass biomass and spatial coverage. Under the SLR scenarios, the current model domain boundaries were maintained, as the land surrounding BB-LEH is unlikely to shift significantly in the future. SLR caused habitat extent to decrease dramatically, pushing seagrass beds toward the coastline with increasing depth, with a 100% loss of habitat by the maximum SLR scenario. The dramatic loss of seagrass habitat under SLR was in part due to the assumption that surrounding land would not be inundated, as the model did not allow for habitat expansion outside the current boundaries of the bay. Temperature increases slightly elevated the rate of summer die-off and decreased habitat area only under the highest temperature increase scenarios. In combined scenarios, the effects of SLR far outweighed the effects of temperature increase. Sensitivity analysis of the model revealed the greatest sensitivity to changes in parameters affecting light limitation and seagrass mortality, but no sensitivity to changes in nutrient limitation constants. The high vulnerability of seagrass in the bay to SLR exceeded that demonstrated for other systems, highlighting the importance of site- and region-specific assessments of estuaries under climate change.

New Jersey↗

USGS2015

Metagenomic analysis of planktonic microbial consortia from a non-tidal urban-impacted segment of James River

Knowledge of the diversity and ecological function of the microbial consortia of James River in Virginia, USA, is essential to developing a more complete understanding of the ecology of this model river system. Metagenomic analysis of James River's planktonic microbial community was performed for the first time using an unamplified genomic library and a 16S rDNA amplicon library prepared and sequenced by Ion PGM and MiSeq, respectively. From the 0.46-Gb WGS library (GenBank:SRR1146621; MG-RAST:4532156.3), 4 × 10 6 reads revealed >3 × 10 6 genes, 240 families of prokaryotes, and 155 families of eukaryotes. From the 0.68-Gb 16S library (GenBank:SRR2124995; MG-RAST:4631271.3; EMB:2184), 4 × 10 6 reads revealed 259 families of eubacteria. Results of the WGS and 16S analyses were highly consistent and indicated that more than half of the bacterial sequences were Proteobacteria , predominantly Comamonadaceae . The most numerous genera in this group were Acidovorax (including iron oxidizers, nitrotolulene degraders, and plant pathogens), which accounted for 10 % of assigned bacterial reads. Polaromonas were another 6 % of all bacterial reads, with many assignments to groups capable of degrading polycyclic aromatic hydrocarbons. Albidiferax (iron reducers) and Variovorax (biodegraders of a variety of natural biogenic compounds as well as anthropogenic contaminants such as polycyclic aromatic hydrocarbons and endocrine disruptors) each accounted for an additional 3 % of bacterial reads. Comparison of these data to other publically-available aquatic metagenomes revealed that this stretch of James River is highly similar to the upper Mississippi River, and that these river systems are more similar to aquaculture and sludge ecosystems than they are to lakes or to a pristine section of the upper Amazon River. Taken together, these analyses exposed previously unknown aspects of microbial biodiversity, documented the ecological responses of microbes to urban effects, and revealed the noteworthy presence of 22 human-pathogenic bacterial genera (e.g., Enterobacteriaceae , pathogenic Pseudomonadaceae , and ‘ Vibrionales' ) and 6 pathogenic eukaryotic genera (e.g., Trypanosomatidae and Vahlkampfiidae). This information about pathogen diversity may be used to promote human epidemiological studies, enhance existing water quality monitoring efforts, and increase awareness of the possible health risks associated with recreational use of James River.

Virginia↗

USGS2022

Forecasting explosions at Sinabung Volcano, Indonesia, based on SO2 emission rates

Dome-building volcanic eruptions are often associated with frequent Vulcanian explosions, which constitute a substantial threat to proximal communities. One proposed mechanism driving such explosions is the sealing of the shallow volcanic system followed by pressurization due to gas accumulation beneath the seal. We investigate this hypothesis at Sinabung Volcano (Sumatra, Indonesia), which has been in a state of eruption since August 2010. In 2013, the volcano began erupting a lava dome and lava flow, and frequent explosions produced eruptive columns that rose many kilometers into the atmosphere and at times sent pyroclastic density currents down the southeast flanks. A network of scanning Differential Optical Absorption Spectrometers (DOAS) was installed on the volcano’s eastern flank in 2016 to continuously monitor SO 2 emission rates during daytime hours. Analysis of the DOAS data from October 2016 to September 2017 revealed that passive SO 2 emissions were generally lower in the 5 days leading up to explosive events (∼100 t/d) than was common in 5-day periods leading up to days on which no explosions occurred (∼200 t/d). The variability of passive SO 2 emissions, expressed as the standard deviation, also took on a slightly wider range of values before days with explosions (0–103 t/d at 1-sigma) than before days without explosions (43–117 t/d). These observations are consistent with the aforementioned seal-failure model, where the sealing of the volcanic conduit blocks gas emissions and leads to pressurization and potential Vulcanian explosions. We develop a forecasting methodology that allows calculation of a relative daily explosion probability based solely on measurements of the SO 2 emission rate in the preceding days. We then calculate forecast explosion probabilities for the remaining SO 2 emissions dataset (October 2017—September 2021). While the absolute accuracy of forecast explosion probabilities is variable, the method can inform the probability of an explosion occurring relative to that on other days in each test period. This information can be used operationally by volcano observatories to assess relative risk. The SO 2 emissions-based forecasting method is likely applicable to other open vent volcanoes experiencing dome-forming eruptions.

Frontiers in Earth Science↗

USGS2023

Global review reveals how disparate study motivations, analytical designs, and focal ions limit understanding of salinization effects on freshwater animals

Global salinization of freshwaters is adversely affecting biotic communities and ecosystem processes. We reviewed six decades (1960–2020) of literature published on animal responses to increased salinities across different taxonomic and ecological contexts and identified knowledge gaps. From 585 journal articles, we characterized 5924 responses of mollusks, crustaceans, zooplankton, non-arthropod invertebrates (NAI), insects, fishes, and amphibians to salinization. Insects and fishes were the most studied taxa; Na + and Cl − were the most studied ions − . Collectively, concentrations of the ions examined typically spanned five orders of magnitude. Species' invasiveness was a key motivation for studying mollusks, crustaceans, and fishes; threats of urbanization and road salts were key motivations for studying NAI, zooplankton, and amphibians. Laboratory studies were more common than field studies for most taxa. Focal life stages in laboratory studies varied widely but juveniles and adults were represented similarly in field studies. Studies of mollusks, NAI, and crustacean focused on adults; studies of zooplankton, insects, fishes, and amphibians focused on juveniles. Organismal- and population-level responses measuring solute uptake, internal chemistry, body condition, or ion concentrations predominated laboratory studies; population- and assemblage-level responses measuring abundance, spatial distribution, or assemblage composition predominated field studies. Negative responses to salinization predominated but positive and unimodal responses were apparent across all taxa and organizational levels. Key topics for further research include a) salinity responses by more taxa, b) responses to especially toxic ions (i.e., potassium, bicarbonate, sulfate, magnesium), c) mechanisms causing positive and unimodal responses, d) traits underpinning responses, e) effects transcending organizational levels, f) ion-specific response thresholds, and g) interactions between salinity and other stressors. Our review suggests inter-taxa variation in sensitivity to salinization reflects occurrence of certain biological traits, including gill-breathing, semi-permeable skin, multiple life stages, and limited mobility. We propose a traits-based framework to predict salinization sensitivity from shared traits. This evolutionary approach could inform management aimed at preventing or reducing adverse impacts of freshwater salinization.

Science of the Total Environment↗

USGS2020

Book review: Proceedings of the First International Snakehead Symposium

Snakehead fishes (family Channidae) are among the most maligned aquatic invasive species in the USA and some other countries where they have been introduced outside of their native range in Asia and Africa. Nevertheless, snakeheads continue to be widely exploited in the live‐food trade in aquaculture and wild‐capture fisheries, are highly sought by anglers, and are also popular in the aquarium trade (Courtenay and Williams 2004). The Northern Snakehead Channa argus is the most widespread of the three channid species that are currently naturalized in the USA. This species has generated much concern and controversy, a situation that is partly fueled by sensational media coverage and B‐grade science fiction horror films, such as “Frankenfish,” “Snakehead Terror,” and “Snakehead Swamp.” Media reports of snakehead introductions are often replete with provocative terms, such as “vicious,” “villain,” “voracious,” “monster,” “diabolical,” and even “ecological Armageddon.” When snakeheads first appeared in natural waters of the USA, fisheries professionals became increasingly interested in their status. Established populations rapidly expanded in the mid‐Atlantic region and Arkansas, with scattered reports of introduced snakeheads from isolated locations in Hawaii, California, North Carolina, Florida, the Upper Midwest, and New England. In 2002, snakeheads were added to the list of injurious fishes under the Lacey Act, thereby prohibiting their importation or transport across state lines without a permit. This symposium was conceived by the editors and other concerned fisheries professionals of the Mississippi River Basin Panel on Aquatic Invasive Species. The mission of the symposium, held in Alexandria, Virginia, in July 2018, was to bring together experts on snakehead biology and ecology and to synthesize existing information into summary papers. In this book, 35 authors contributed to 15 peer‐reviewed articles that detail the current state of knowledge about snakehead introductions in the USA. Additionally, 16 abstracts are included from meeting presentations that were not accompanied by full‐length manuscripts. Also included is a summary of a facilitated symposium panel discussion featuring eight experts representing state and federal natural resource agencies and private fishing organizations. The book is organized into six sections. In the first section (Distribution), three papers provide an overview of the Channa species introduced into the USA and historical accounts of occurrence and dispersal of the Northern Snakehead in the mid‐Atlantic region and Arkansas. The second section (Biology/Ecology) consists of two articles that examine growth and energetics of Northern Snakehead populations and two papers that investigate diet, diel feeding activity, and movement of this species in the Potomac River drainage. The third section (Monitoring/Response) includes a paper that models range expansion of the Northern Snakehead in the southeastern USA based on occurrence data and environmental conditions. Also included in this section is a paper summarizing an environmental DNA study to assess the status and range of the Bullseye Snakehead C. marulius in southern Florida. The fourth section (Management/Control) is comprised of four papers that address harvest, age and growth, and development of a stock–recruitment model to inform management decisions regarding control and mitigation for Northern Snakehead populations in the greater Chesapeake Bay area. The fifth section (Perspectives) includes a paper on the history of snakehead introductions in Japan and a thought‐provoking social commentary on the human dimensions of Northern Snakehead management. Abstracts in the final section provide brief summaries of a diversity of snakehead studies, including aspects of distribution, ecology, behavior, control and monitoring efforts, public outreach, and pathology. The summary of the panel discussion is an engaging dialogue about the challenges of snakehead management in the context of conflicts regarding snakeheads as injurious versus their value as game and food species. Most of this book is focused on the Northern Snakehead. Much has been done to document snakehead distributions and certain aspects of snakehead biology, such as diets, age, and growth. Less research has been devoted to understanding the ecological impacts of snakeheads to native aquatic communities and ecosystems. This book would have benefited from a chapter summarizing the current systematics and diversity of the Channidae to inform fisheries biologists about the morphological characteristics of the family, approximate numbers of genera and species, and taxonomic instability. Exemplifying the latter, recent molecular and morphological evidence indicates uncertainty regarding identification of the feral snakehead population in Florida (Adamson and Britz 2019). Those authors suggest that this population may have originated from western Thailand, a possibility that could have implications for understanding historical pathways of snakehead introductions into the USA. In comparison with many published AFS symposia, this volume is relatively narrow in scope and lacks cohesive integration. It will primarily be of interest to those fisheries professionals engaged in the study of snakeheads as well as other nonnative species for which there are contrasting social values regarding their management: whether to monitor and attempt control or eradication efforts or to maintain populations for harvest as game or food species. The book should serve to identify information gaps and guide future research.

Transactions of the American Fisheries Society↗

USGS1987

Recent changes in Lake Michigan's fish community and their probable causes, with emphasis on the role of the alewife (Alosa pseudoharengus)

Deepwater ciscoes ( Coregonus spp.) or "chubs" of Lake Michigan far surpassed those of Lake Huron in yield, population density, and resilience following severe depletion in the 1960s and 1970s, when the bloater ( C . hoyi ) composed more than 90% of the stocks. The population decline of bloaters in recent decades was mainly attributed to exploitation, to the depression of chub recruitment (e.g. from inferred predation on early life stages) by nonendemic alewives ( Alosa pseudoharengus ) and rainbow smelt ( Osmerus mordax ), and to complications arising from extreme female predominance that was best documented for Lake Michigan. The various interactions between bloaters and the nonendemic species, which were intensified after the loss of large predators to sea lamprey ( Petromyzon marinus ), would help to explain why a stock–recruitment relation was not shown for the Lake Michigan bloater. We hypothesize that reproductive inefficiency caused by a shift to strong female predominance in the bloater depresses recruitment and thus helps to regulate abundance. However, the low resilience that sex imbalance seems to impart makes the stock unstable when exploited. It should therefore be exploited conservatively during such periods. Also, the sex ratio and its direction of change appear to be important qualifiers when surplus production is estimated from stock size.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS1998

Paleoclimate simulations for North America over the past 21,000 years: Features of the simulated climate and comparisons with paleoenvironmental data

Maps of upper-level and surface winds and of surface temperature and precipitation illustrate the results of a sequence of global paleoclimatic simulations spanning the past 21,000 yr for North America. We review (a) the large-scale features of circulation, temperature, and precipitation that appear in the simulations from the NCAR Community Climate Model Version 1 (CCM 1), (b) the implications of the simulated climate for the past continental-scale distributions of three plant taxa ( Picea spp., Pseudotsuga menziesii , and Artemisia tridentata ), which are broadly representative of the vegetation across the continent, and (c) the potential explanations in terms of atmospheric circulation or surface energy- and water-balance processes for mismatches between the simulations and observations. Most of the broad-scale features of previous paleoclimatic simulations with the NCAR CCM 0 for North America are present in the current simulations. Many of the elements of a conceptual model (based on previous climate simulations) that describes the controls of paleoclimatic variations across North America during the past 21,000 yr are found in simulations reviewed here. These include (1) displacement of the jet stream by the Laurentide Ice Sheet to the south of its present position in both winter and summer, (2) generation of a ‘glacial anticyclone’ over the ice sheet at the LGM, and the consequent induction of large-scale sinking motions induced over eastern North America, (3) changes in the strength of surface atmospheric circulation features through time, including weakening of the Aleutian low in winter, and strengthening of the eastern Pacific and Bermuda high-pressure systems in summer as the ice sheet decreased in size, (4) development of a ‘heat low’ at the surface and a strengthened ridge in the upper-atmosphere over the continent at the time of the maximum summer insolation anomaly, (5) increases in summer temperature earlier in regions remote from the ice sheet (these increases appear earlier in the present (CCM 1) simulations than in the previous (CCM 0) ones, however), and (6) continuation of negative winter temperature anomalies into the middle Holocene. In general, simulated surface conditions that are discordant with paleoenvironmental observations can be attributed to the simulation of particular atmospheric circulation patterns (e.g. those that suppress precipitation or advect warm air into a region), with these mismatches amplified in Beringia and the southeastern United States by surface energy- and water-balance processes.

Quaternary Science Reviews↗

USGS2024

Rapid simulation of wave runup on morphologically diverse, reef-lined coasts with the BEWARE-2 (Broad-range Estimator of Wave Attack in Reef Environments) meta-process model

Low-lying, tropical, coral-reef-lined coastlines are becoming increasingly vulnerable to wave-driven flooding due to population growth, coral reef degradation, and sea-level rise. Early-warning systems (EWSs) are needed to enable coastal authorities to issue timely alerts and coordinate preparedness and evacuation measures for their coastal communities. At longer timescales, risk management and adaptation planning require robust assessments of future flooding hazard considering uncertainties. However, due to diversity in reef morphologies and complex reef hydrodynamics compared to sandy shorelines, there have been no robust analytical solutions for wave runup to allow for the development of large-scale coastal wave-driven flooding EWSs and risk assessment frameworks for reef-lined coasts. To address the need for fast, robust predictions of runup that account for the natural variability in coral reef morphologies, we constructed the BEWARE-2 (Broad-range Estimator of Wave Attack in Reef Environments) meta-process modeling system. We developed this meta-process model using a training dataset of hydrodynamics and wave runup computed by the XBeach Non-Hydrostatic process-based hydrodynamic model for 440 combinations of water level, wave height, and wave period with 195 representative reef profiles that encompass the natural diversity in real-world fringing coral reef systems. Through this innovation, BEWARE-2 can be applied in a larger range of coastal settings than meta-models that rely on a parametric description of the coral reef geometry. In the validation stage, the BEWARE-2 modeling system produced runup results that had a relative root mean square error of 13% and relative bias of 5% relative to runup simulated by XBeach Non-Hydrostatic for a large range of oceanographic forcing conditions and for diverse reef morphologies (root mean square error and bias 0.63 and 0.26 m, respectively, relative to mean simulated wave runup of 4.85 m). Incorporating parametric modifications in the modeling system to account for variations in reef roughness and beach slope allows for systematic errors (relative bias) in BEWARE-2 predictions to be reduced by a factor of 1.5–6.5 for relatively coarse or smooth reefs and mild or steep beach slopes. This prediction provided by the BEWARE-2 modeling system is faster by 4–5 orders of magnitude than the full, process-based hydrodynamic model and could therefore be integrated into large-scale EWSs for tropical, reef-lined coasts and used for large-scale flood risk assessments.

Natural Hazards and Earth System Sciences↗

USGS2020

Understanding the relationship between stream metabolism and biological assemblages

Biological assemblages are commonly used for assessing stream health, but there is increased interest among the freshwater research community in incorporating measures of stream function, such as metabolism, to strengthen stream-health assessments. Presently, there is limited information about the relationships between stream metabolism and biological assemblages, along with the measurement period required to relate metabolism with stream biota. Our study assessed which environmental factors explained stream metabolism and to what degree stream metabolism and minimum dissolved oxygen (DOmin) were related to invertebrate and fish metrics in streams distributed across several regions of the United States. Furthermore, we evaluated the number of metabolism monitoring days required for maximizing the ability to detect relationships between stream metabolism and biological assemblage metrics. We sampled 17 sites distributed among reference, agricultural, and urban areas for stream metabolism, nutrients, habitat, and biological assemblages (invertebrates and fishes). Overall, sites were heterotrophic with gross primary production (GPP) and ecosystem respiration (ER) related primarily to days since last high flow, canopy cover, maximum water temperature, and total phosphorus. DOmin was related to days since last high flow, canopy cover, and maximum water temperature. We were unable to determine a clear statistical relationship between invertebrate metrics (invertebrate richness; Ephemeroptera, Plecoptera, and Trichoptera richness; and scraper-taxa richness) and GPP, ER, or DOmin. In contrast, we found that 2 fish-assemblage metrics were associated with stream metabolism and DOmin. A fish multimetric index (FMMI) was negatively correlated with GPP ( r = −0.5, p = 0.048) and positively correlated with DOmin ( r = 0.47, p = 0.06). Percentage of omnivorous fish taxa was positively correlated with GPP ( r = 0.72, p = 0.001) and ER ( r = 0.55, p = 0.02) and negatively correlated with DOmin ( r = −0.67, p = 0.003). The lack of detected relationships for most of the biological-assemblage metrics with stream metabolism may be partially due to 1 or more factors, including high variability, low sample size, limited range in metabolism values, assemblage metrics used, and geographic distribution of sites. Comparing stream-metabolism measurement periods (in days) to biological-assemblage metrics indicated that optimum correlations occurred at 2 d for DOmin, 3 d for GPP, and 14 d for ER. Although our study found limited relationships of stream metabolism and DOmin with biological assemblages, future studies should consider a larger sample size (≥30), 14-d or longer metabolism measurement period, and assessment of other taxa-specific or assemblage metrics.

Freshwater Science↗

USGS2024

Probabilistic assessment of postfire debris-flow inundation in response to forecast rainfall

Communities downstream of burned steep lands face increases in debris-flow hazards due to fire effects on soil and vegetation. Rapid postfire hazard assessments have traditionally focused on quantifying spatial variations in debris-flow likelihood and volume in response to design rainstorms. However, a methodology that provides estimates of debris-flow inundation downstream of burned areas based on forecast rainfall would provide decision-makers with information that directly addresses the potential for downstream impacts. We introduce a framework that integrates a 24 h lead-time ensemble precipitation forecast with debris-flow likelihood, volume, and runout models to produce probabilistic maps of debris-flow inundation. We applied this framework to simulate debris-flow inundation associated with the 9 January 2018 debris-flow event in Montecito, California, USA. When the observed debris-flow volumes were used to drive the probabilistic forecast model, analysis of the simulated inundation probabilities demonstrates that the model is both reliable and sharp. In the fully predictive model, however, in which debris-flow likelihood and volume were computed from the atmospheric model ensemble's predictions of peak 15 min rainfall intensity, I 15 , the model generally under-forecasted the inundation area. The observed peak I 15 lies in the upper tail of the atmospheric model ensemble spread; thus a large fraction of ensemble members forecast lower I 15 than observed. Using these I 15 values as input to the inundation model resulted in lower-than-observed flow volumes which translated into under-forecasting of the inundation area. Even so, approximately 94 % of the observed inundated area was forecast to have an inundation probability greater than 1 %, demonstrating that the observed extent of inundation was generally captured within the range of outcomes predicted by the model. Sensitivity analyses indicate that debris-flow volume and two parameters associated with debris-flow mobility exert significant influence on inundation predictions, but reducing uncertainty in postfire debris-flow volume predictions will have the largest impact on reducing inundation outcome uncertainty. This study represents a first step toward a near-real-time hazard assessment product that includes probabilistic estimates of debris-flow inundation and provides guidance for future improvements to this and similar model frameworks by identifying key sources of uncertainty.

California↗