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USGS2018

Annotated bibliography of scientific research on greater sage-grouse published since January 2015

The greater sage-grouse ( Centrocercus urophasianus ; hereafter GRSG) has been a focus of scientific investigation and management action for the past two decades. The 2015 U.S. Fish and Wildlife Service listing determination of “not warranted” was in part due to a large-scale collaborative effort to develop strategies to conserve GRSG populations and their habitat and to reduce threats to both. New scientific information augments existing knowledge and can help inform updates or modifications to existing plans for managing GRSG and sagebrush ecosystems. However, the sheer number of scientific publications can be a challenge for managers tasked with evaluating and determining the need for potential updates to existing planning documents. To assist in this process, the U.S. Geological Survey (USGS) has reviewed and summarized the scientific literature published since January 1, 2015. To identify articles and reports published about GRSG, we first conducted a structured search of three reference databases (Web of Science, Scopus, and Google Scholar) using the search term “greater sage-grouse.” We refined the initial list of products by (1) removing duplicates, (2) excluding products that were not published as research or scientific review articles in peer-reviewed journals or as formal government technical reports, and (3) retaining only those products for which GRSG or their habitat was a research focus. We summarized the contents of each product by using a consistent structure (background, objectives, methods, location, findings, and implications) and assessed the content of each product relevant to a list of 31 management topics. These topics include GRSG biology and habitat characteristics along with potential management actions, land uses, and environmental factors related to GRSG management and conservation. We also noted which articles/reports created new geospatial data. The final search was conducted on January 6, 2018, and application of our criteria resulted in the inclusion of 169 published products (2 of these products were published corrections to journal articles). The management topics most commonly addressed were GRSG behavior or demographics and GRSG habitat selection or habitat characteristics at broad or site scales. Few products addressed captive breeding, recreation, wild horses and burros, and range management structures (including fences). We include in this annotated bibliography the full citation, product summary, and management topics addressed by each product. The online version of this bibliography ( https://apps.usgs.gov/gsgbib/index.php ) is searchable by topic and location and includes links to the original publications. A substantial body of literature has been compiled based on research explicitly related to the conservation, management, monitoring, and assessment of GRSG. These studies may inform planning and management actions that seek to balance conservation, economic, and social objectives and manage diverse resource uses and values across the western United States. The review process for this product included requesting input on each summary from one or more authors of the original peer-reviewed article or report and a formal review of the entire document by three independent reviewers and, subsequently, the USGS Bureau Approving Official. This process is consistent with USGS Fundamental Science Practices.

Open-File Report↗

USGS2022

Phenological variation in spring migration timing of adult alewife (Alosa pseudoharengus) in coastal Massachusetts

The timing of biological events in plants and animals, such as migration and reproduction, is shifting due to climate change. Anadromous fishes are particularly susceptible to these shifts as they are subject to strong seasonal cycles when transitioning between marine and freshwater habitats to spawn. We used linear models to determine the extent of phenological shifts in adult Alewife Alosa pseudoharengus as they migrated from ocean to freshwater environments during spring to spawn at 12 sites along the northeastern USA. We also evaluated broadscale oceanic and atmospheric drivers that trigger their movements from offshore to inland habitats, including sea surface temperature, North Atlantic Oscillation index, and Gulf Stream index. Run timing metrics of initiation, median (an indicator of peak run timing), end, and duration were found to vary among sites. Although most sites showed negligible shifts towards earlier timing, statistically significant changes were detected in three systems. Overall, winter sea surface temperature, spring and fall transition dates, and annual run size were the strongest predictors of run initiation and median dates, while a combination of within-season and seasonal-lag effects influenced run end and duration timing. Disparate results observed across the 12 spawning runs suggest that regional environmental processes were not consistent drivers of phenology and local environmental and ecological conditions may be more important. Additional years of data to extend time series and monitoring of Alewife timing and movements in nearshore habitats may provide important information about staging behaviors just before adults transition between ocean and freshwater habitats.

Massachusetts↗

USGS2007

Is there a risk associated with the insect repellent DEET (N,N-diethyl-m-toluamide) commonly found in aquatic environments?

DEET ( N , N -diethyl- m -toluamide) is the active ingredient of most commercial insect repellents. This compound has commonly been detected in aquatic water samples from around the world indicating that DEET is both mobile and persistent, despite earlier assumptions that DEET was unlikely to enter aquatic ecosystems. DEET's registration category does not require an ecological risk assessment, thus information on the ecological toxicity of DEET is sparse. This paper reviews the presence of DEET in aqueous samples from around the world (e.g. drinking water, streams, open seawater, groundwater and treated effluent) with reported DEET concentrations ranging from 40–3000 ng L − 1 . In addition, new DEET data collected from 36 sites in coastal waterways from eastern Australia (detections ranging from 8 to 1500 ng L − 1 ) are examined. A summary of new and existing toxicity data are discussed with an emphasis on preparing a preliminary risk assessment for DEET in the aquatic environment. Collated information on DEET in the aquatic environment suggests risk to aquatic biota at observed environmental concentrations is minimal. However, the information available was not sufficient to conduct a full risk assessment due to data deficiencies in source characterisation, transport mechanisms, fate, and ecotoxicity studies. These risks warrant further investigation due to the high frequency that this organic contaminant is detected in aquatic environments around the world.

Science of the Total Environment↗

USGS2008

Chapter 31 Sensitivity and spin-up times of cohesive sediment transport models used to simulate bathymetric change

Bathymetric change in tidal environments is modulated by watershed sediment yield, hydrodynamic processes, benthic composition, and anthropogenic activities. These multiple forcings combine to complicate simple prediction of bathymetric change; therefore, numerical models are necessary to simulate sediment transport. Errors arise from these simulations, due to inaccurate initial conditions and model parameters. We investigated the response of bathymetric change to initial conditions and model parameters with a simplified zero-dimensional cohesive sediment transport model, a two-dimensional hydrodynamic/sediment transport model, and a tidally averaged box model. The zero-dimensional model consists of a well-mixed control volume subjected to a semidiurnal tide, with a cohesive sediment bed. Typical cohesive sediment parameters were utilized for both the bed and suspended sediment. The model was run until equilibrium in terms of bathymetric change was reached, where equilibrium is defined as less than the rate of sea level rise in San Francisco Bay (2.17 mm/year). Using this state as the initial condition, model parameters were perturbed 10% to favor deposition, and the model was resumed. Perturbed parameters included, but were not limited to, maximum tidal current, erosion rate constant, and critical shear stress for erosion. Bathymetric change was most sensitive to maximum tidal current, with a 10% perturbation resulting in an additional 1.4 m of deposition over 10 years. Re-establishing equilibrium in this model required 14 years. The next most sensitive parameter was the critical shear stress for erosion; when increased 10%, an additional 0.56 m of sediment was deposited and 13 years were required to re-establish equilibrium. The two-dimensional hydrodynamic/sediment transport model was calibrated to suspended-sediment concentration, and despite robust solution of hydrodynamic conditions it was unable to accurately hindcast bathymetric change. The tidally averaged box model was calibrated to bathymetric change data and shows rapidly evolving bathymetry in the first 10-20 years, though sediment supply and hydrodynamic forcing did not vary greatly. This initial burst of bathymetric change is believed to be model adjustment to initial conditions, and suggests a spin-up time of greater than 10 years. These three diverse modeling approaches reinforce the sensitivity of cohesive sediment transport models to initial conditions and model parameters, and highlight the importance of appropriate calibration data. Adequate spin-up time of the order of years is required to initialize models, otherwise the solution will contain bathymetric change that is not due to environmental forcings, but rather improper specification of initial conditions and model parameters. Temporally intensive bathymetric change data can assist in determining initial conditions and parameters, provided they are available. Computational effort may be reduced by selectively updating hydrodynamics and bathymetry, thereby allowing time for spin-up periods. reserved.

Proceedings in Marine Science↗

USGS2018

Evaluating spatial and temporal variability in growth and mortality for recreational fisheries with limited catch data

Understanding the spatial and temporal variability in life-history traits among populations is essential for the management of recreational fisheries. However, valuable freshwater recreational fish species often suffer from a lack of catch information. In this study, we demonstrated the use of an approach to estimate the spatial and temporal variability in growth and mortality in the absence of catch data and apply the method to riverine smallmouth bass ( Micropterus dolomieu ) populations in Pennsylvania, USA. Our approach included a growth analysis and a length-based analysis that estimates mortality. Using a hierarchical Bayesian approach, we examined spatial variability in growth and mortality by assuming parameters vary spatially but remain constant over time and temporal variability by assuming parameters vary spatially and temporally. The estimated growth and mortality of smallmouth bass showed substantial variability over time and across rivers. We explored the relationships of the estimated growth and mortality with spring water temperature and spring flow. Growth rate was likely to be positively correlated with these two factors, while young mortality was likely to be positively correlated with spring flow. The spatially and temporally varying growth and mortality suggest that smallmouth bass populations across rivers may respond differently to management plans and disturbance such as environmental contamination and land-use change. The analytical approach can be extended to other freshwater recreational species that also lack of catch data. The approach could also be useful in developing population assessments with erroneous catch data or be used as a model sensitivity scenario to verify traditional models even when catch data are available.

Pennsylvania↗

USGS2023

State of the science and decision support for measuring suspended sediment with acoustic instrumentation

Acoustic instrumentation can be used to provide time-series and discrete estimates of suspended-sediment concentration, load, and sediment particle sizes in fluvial systems, which are essential for creating informed solutions to many sediment-related environmental, engineering, and land management concerns. Historically, scientists have developed relations between suspended sediment characteristics and other parameters, most commonly streamflow, to estimate sediment information when physical sediment samples cannot be collected. Approaches using streamflow can have substantial accuracy limitations because of hysteresis effects, giving rise to the use of more direct surrogate approaches such as acoustic methods. Interagency efforts in recent years have advanced the testing, methods development, operational guidelines, and training on acoustic methods for measuring suspended sediment. Scientists interested in using these methods are faced with many decisions on the type of application and deployment: horizontal profiling, vertical profiling, or point acoustic instruments; single or multifrequency instruments; continuous or discrete sediment measurements; and fixed or mobile instrument deployments. To promote cost-effective, accurate, and high-resolution fluvial sediment data for the Nation, the interagency Sediment Acoustic Leadership Team (SALT) develops technical guidance and training for using acoustic instruments to measure aquatic sediment. Even though acoustic instrumentation has been used successfully to measure suspended-sediment characteristics throughout the world, some deployments have been unsuccessful because of limited technical guidance and selection of an inappropriate method. To guide decisions on method selection, the SALT has compiled the state of the science for the main types of acoustics-based suspended-sediment measurement methods in development, testing, and use, and has created a flowchart to guide method selection.

Conference Paper↗

USGS2026

Guidelines for producing integrated 210Pb and 14C age-models

Accurate reconstructions of past environmental changes are crucial in paleoecological research and require reliable chronologies of sedimentary archives. Establishing robust age-models and obtaining the most appropriate proxies for analysis is a complex scientific endeavor, requiring extensive resources and collaboration among specialists, including radiochronologists. Radiometric dating methods, such as 210 Pb and radiocarbon ( 14 C), are frequently employed to establish chronologies in aquatic sedimentary deposits and peat bogs. In this study, we review key aspects of sampling, analysis, and the principles underlying 210 Pb and 14 C age-models, focusing on methods for developing robust joint chronologies for paleoenvironmental research. Drawing largely from the authors' experiences and group discussions during and after a scientific workshop in 2022, we discuss important considerations for site selection, sampling strategies, and radiometric dating to construct integrated 210 Pb and 14 C age-models. Using expert consensus, this group – called Paleostats – aims to provide a set of best practices for other geochronologists with this methods paper. Among our conclusions, we emphasize the importance of accounting for site-specific factors such as prior information on sedimentation rates to establish appropriate sampling and analytical strategies. The use of appropriate coring devices can minimize disturbance to sediments and ensure the core surface remains intact and preserved until sectioning. Where excess 210 Pb is expected, sectioning at intervals of ≤1 cm provides an adequate sampling resolution for 210 Pb dating. Exceptions are possible, allowing for ~2–3 cm sections in areas with confirmed high sedimentation rates (e.g., > 1 cm yr −1 ). Recovering deeper core sections for 14 C dating with sufficient overlap allows for accounting errors in depth estimates made in the field. Special attention is advised during time intervals where validation proxies, such as the human-made radionuclides 137 Cs or post-bomb 14 C, are expected, and to determine the depth of secular equilibrium between 210 Pb and 226 Ra. Radiocarbon analyses are commonly performed by accelerator mass spectrometry, and age models are constructed mainly using Bayesian statistics with Markov Chain Monte Carlo techniques (e.g., Bacon ). A Bayesian approach ( Plum ) is now available for producing 210 Pb age-models, which infers the 210 Pb ex flux, eliminates the need for selecting an equilibrium depth, and allows dating cores with incomplete 210 Pb ex inventory. Plum offers improved chronologies by integrating raw 210 Pb and 14 C data, and these age-models can be enriched with other dating methodologies, such as identifying tephras and other well-recorded historical events. Harmonized reporting would contribute to making radiometric age-models reproducible, which would benefit from an international effort. Using 210 Pb and 14 C to produce integrated age-models may yield better insights into the interplay between natural and recent anthropogenic forcings on ecosystems. This can enhance our understanding of environmental processes and their impacts on climate change, ultimately supporting science-based assessments and decisions.

Earth-Science Reviews↗

USGS2002

Identification of lithofacies using Kohonen self-organizing maps

Lithofacies identification is a primary task in reservoir characterization. Traditional techniques of lithofacies identification from core data are costly, and it is difficult to extrapolate to non-cored wells. We present a low-cost automated technique using Kohonen self-organizing maps (SOMs) to identify systematically and objectively lithofacies from well log data. SOMs are unsupervised artificial neural networks that map the input space into clusters in a topological form whose organization is related to trends in the input data. A case study used five wells located in Appleton Field, Escambia County, Alabama (Smackover Formation, limestone and dolomite, Oxfordian, Jurassic). A five-input, one-dimensional output approach is employed, assuming the lithofacies are in ascending/descending order with respect to paleoenvironmental energy levels. To consider the possible appearance of new logfacies not seen in training mode, which may potentially appear in test wells, the maximum number of outputs is set to 20 instead of four, the designated number of lithosfacies in the study area. This study found eleven major clusters. The clusters were compared to depositional lithofacies identified by manual core examination. The clusters were ordered by the SOM in a pattern consistent with environmental gradients inferred from core examination: bind/boundstone, grainstone, packstone, and wackestone. This new approach predicted lithofacies identity from well log data with 78.8% accuracy which is more accurate than using a backpropagation neural network (57.3%). The clusters produced by the SOM are ordered with respect to paleoenvironmental energy levels. This energy-related clustering provides geologists and petroleum engineers with valuable geologic information about the logfacies and their interrelationships. This advantage is not obtained in backpropagation neural networks and adaptive resonance theory neural networks. ?? 2002 Elsevier Science Ltd. All rights reserved.

Computers & Geosciences↗

USGS2011

Partially melted granodiorite and related rocks ejected from Crater Lake caldera, Oregon

Blocks of medium-grained granodiorite to 4 m, and minor diabase, quartz diorite, granite, aplite and granophyre, are common in ejecta of the ∼6,900 yrBP calderaforming eruption of Mount Mazama. The blocks show degrees of melting from 0–50 vol%. Because very few have adhering juvenile magma, it is thought that the blocks are fragments of the Holocene magma chamber's walls. Primary crystallisation of granodiorite produced phenocrystic pl + hyp + aug + mt + il + ap + zc, followed by qz + hb + bt + alkali feldspar (af). Presence of fluid inclusions in all samples implies complete crystallisation before melting. Subsolidus exchange with meteoric hydrothermal fluids before melting is evident in δ 18 O values of −3·4+4·9‰ for quartz and plagioclase in partially melted granodiorites (fresh lavas from the region have δ 18 O values of +5·8−+7·0‰); δ 18 O values of unmelted granodiorites from preclimatic eruptive units suggest hydrothermal exchange began between ∼70 and 24 ka. Before eruption, the granitic rocks equilibrated at temperatures, estimated from Fe-Ti oxide compositions, of up to ∼1000°C for c. 10 2 –10 4 years at a minimum pressure of 100-180 MPa. Heating caused progressive breakdown or dissolution of hb, af, bt, and qz, so that samples with the highest melt fractions have residual pl + qz and new or re-equilibrated af + hyp + aug + mt + il in high-silica rhyolitic glass (75-77% SiO 2 ). Mineral compositions vary systematically with increasing temperature. Hornblende is absent in rocks with Fe-Ti oxide temperatures >870°C, and bt above 970°C. Oxygen isotope fractionation between qz, pl, and glass in partially fused granodiorite also is consistent with equilibration at T≥900°C (Δ 18 O qz.pl = +0·7 ± 0·5‰). Element partitioning between glass and crystals reflects the large fraction of refractory pl, re-equilibration of af and isolation or incomplete dissolution of accessory phases. Ba and REE contents of analysed glass separates can be successfully modelled by observed degrees of partial melting of granodiorite, but Rb, Sr and Sc concentrations cannot. Several samples have veins of microlite-free glass 1–5 mm thick that are compositionally and physically continuous with intergranular melt and which apparently formed after the climactic eruption began. Whole-rock H 2 O content, microprobe glass analysis sums near 100% and evidence for high temperature suggest liquids in the hotter samples were nearly anhydrous. The occurrence of similar granodiorite blocks at all azimuths around the 8 × 10 km caldera implies derivation from one pluton. Compositional similarity between granodiorite and pre-Mazama rhyodacites suggests that the pluton may have crystallised as recently as 0·4 Ma; compositional data preclude crystallisation from the Holocene chamber. The history of crystallisation, hydrothermal alteration, and remelting of the granitic rocks may be characteristic of shallow igneous systems in which the balance between hydrothermal cooling and magmatic input changes repeatedly over intervals of 10 4 -10 6 years.

Oregon↗

USGS2024

A meta-analysis of mercury biomagnification in freshwater predatory invertebrates: Community diversity and dietary exposure drive variability

Accurate estimates of methylmercury (MeHg) exposure are valuable to actionably assess risk and protect wildlife and human health. MeHg trophic transfer is a critical driver of risk: MeHg is generally biomagnified by a factor of 8.3 ± 7.5 from one trophic level to the next, averaged across freshwater communities (mean ± standard deviation). This variability can produce disparate risks even where basal MeHg concentrations are similar. Taxonomy may be one driver of this variability: physiologically diverse groups, like vertebrates and invertebrates, may assimilate MeHg differently. To determine whether taxonomy affects trophic transfer efficiency, we conducted a meta-analysis characterizing predatory invertebrate MeHg biomagnification. Our analyses estimated that freshwater predatory invertebrates biomagnify MeHg by factors of 2.1 ± 0.2 to 4.3 ± 0.3, with a 98.9 ± 0.4% posterior probability that factors are below 5 (mean ± standard error). When vertebrates or primary producers were included, a site’s trophic magnification factor was 18.6 ± 6.2 to 54.1 ± 7.7% higher than estimates for invertebrates alone. Biomagnification was inversely correlated to prey MeHg concentration and varied among systematic and functional groups. These data suggest that predatory invertebrates biomagnify MeHg less efficiently than vertebrates and that a community’s diversity and structure determine its biomagnification efficiency. Incorporating organismal variation in trophic transfer estimates may improve the assessment, communication, and management of MeHg risk.

Environmental Science & Technology↗

USGS2018

Water stress from high-volume hydraulic fracturing potentially threatens aquatic biodiversity and ecosystem services in Arkansas, United States

Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and “frack” ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7–51% of catchments from June–November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.

Arkansas↗

USGS2020

Septic systems and rainfall influence human fecal markers and indicator organisms occurrence in private wells in southeastern Pennsylvania

In the United States approximately 48 million people are served by private wells. Unlike public water systems, private well water quality is not monitored and there are few studies on the extent and sources of contamination of private wells. We extensively investigated five private wells to understand the variability in microbial contamination, the role of septic systems as sources of contamination, and the effect of rainfall on well water quality. From 2016-2017, weekly or biweekly samples (n= 105) were collected from 5 private wells in rural Pennsylvania. Samples were tested for general water quality parameters, conventional and sewage-associated microbial indicators, and human pathogens. Total coliforms, human Bacteroides (HF183), and pepper mild mottle virus were detected at least once in all wells. Regression revealed significant relationships between HF183 and rainfall 8-14 days prior to sampling and between total coliforms and rainfall 8-14 or 0-14 days prior to sampling. Dye tracer studies at 3 wells confirmed the impact of household septic systems on well contamination. Microbiological measurements, chemical water quality data, and dye tracer tests provide evidence of human fecal contamination in the private wells studied, suggesting that household septic systems are the source of this contamination.

Pennsylvania↗

USGS2021

National Park Service Vegetation Mapping Inventory Program: Great Smoky Mountains National Park vegetation mapping project

The National Park Service (NPS) Vegetation Mapping Inventory (VMI) Program is an effort to classify, describe, and map existing vegetation communities in national park units throughout the United States. The NPS VMI Program is managed by the NPS Natural Resource Stewardship and Science Inventory and Monitoring Program and provides baseline vegetation information to natural resource managers, researchers, and ecologists. The U.S. Geological Survey Upper Midwest Environmental Sciences Center, NatureServe, and NPS Great Smoky Mountains National Park (GRSM, also referred to as the “Park”) have completed vegetation classification and mapping of GRSM, including the Foothills Parkway, for the NPS VMI Program. Mappers, ecologists, and botanists collaborated to affirm vegetation types of GRSM and to determine how best to map the vegetation types by using aerial imagery. A vegetation classification developed in 2003 by NatureServe and the NPS served as a foundation to further classify and map the vegetation types of the Park. Data from an additional 10 vegetation plots supported vegetation types either rare or not documented in the 2003 classification. Data from 203 verification sites were collected to test the field key to vegetation types and the application of vegetation types to a sample set of map polygons. Furthermore, data from 972 accuracy assessment (AA) sites were collected (of which 966 were used to test accuracy of the vegetation map layer). This GRSM vegetation mapping project identified 112 vegetation types consisting of 105 association types in the U.S. National Vegetation Classification (USNVC), 2 “park-special” types, 1 “map-special” type, and 4 cultural types in the USNVC. To map the vegetation and land cover of GRSM, 52 map classes were developed. Of these 52 map classes, 46 represent natural (including ruderal) vegetation types, most of which types are recognized in the USNVC. For the remaining 6 of the 52 map classes, 4 represent USNVC cultural types for agricultural and developed areas, and 2 represent non-USNVC types for nonvegetated open water and nonvegetated rock. Features were interpreted from viewing four-band digital aerial imagery using digital onscreen three-dimensional stereoscopic workflow systems in geographic information systems; digital aerial imagery was collected during September 23–October 30, 2015. The interpreted data were digitally and spatially referenced, thus making the spatial-database layers usable in a geographic information system. Polygon units were mapped to either a 0.5- or 0.25- hectare (ha) minimum mapping unit, depending on vegetation type. A geodatabase containing several feature-class layers and tables provides the locations and data of USNVC vegetation types (vegetation map layer), vegetation plots, verification sites, AA sites, project boundary extent, and aerial image centers and flight lines. Covering 210,875 ha, the feature-class layer and related tables for the vegetation map layer provide 34,084 polygons of detailed attribute data when special modifiers are not considered (average polygon size of 6.2 ha) and 36,589 polygons of detailed attribute data when special modifiers are considered (average polygon size of 5.8 ha). Each map polygon is assigned a map-class code and name and, when applicable, are linked to USNVC classification tables within the geodatabase. The vegetation map extent includes the administrative boundary for GRSM and the Foothills Parkway. A summary report, generated from the vegetation map layer, concludes that the 46 map classes representing natural (including ruderal) vegetation types apply to 99.2% of polygons (33,797 polygons; average size of 6.2 ha) and cover 98.6% of the Park (207,971.4 ha). Further broken down, map classes representing natural vegetation types indicate that the Park is 97.7% forest and woodland (205,882.5 ha), 0.6% shrubland (1,174.6 ha), and 0.4% herbaceous (914.3 ha). Map classes representing cultural vegetation types apply to 0.8% of polygons (259 polygons; average size of 4.9 ha) and cover 0.6% of the Park (1,277.4 ha). Map classes representing nonvegetation open and flowing water and unvegetated rock apply to 0.08% of polygons (28 polygons; average size of 58.1 ha) and cover 0.8% of the Park (1,625.9 ha). A thematic AA study was completed of map classes representing the natural (including ruderal) vegetation types of the Park. Initial AA results were discussed with NPS staff from the Park. Following input from NPS staff on how to handle map classes that fell below accuracy standards, adjustments were made to the vegetation map layer. Final results indicate an overall accuracy of 80.64% (kappa index of 79.96% for chance agreements) based on data from 966 of the 972 AA sites. Most individual map-class themes exceed the NPS VMI Program standard of 80% with a 90% confidence interval. The GRSM vegetation mapping project delivers many geospatial and vegetation data products, including an in-depth project report discussing methods and results, which includes map classification and map-class descriptions. This suite of products also includes descriptions and a field key to vegetation types; a database of vegetation plots, verification sites, and AA sites; digital images of field sites; field data sheets; digital aerial imagery; hardcopy and digital maps; a geodatabase of vegetation and land cover (map layer), field sites (vegetation plots, verification sites, and AA sites), aerial imagery index, project boundary, and metadata; and a contingency table listing AA results. Geospatial products are projected in the Universal Transverse Mercator, Zone 17 North, by using the North American Datum of 1983. Information on the NPS VMI Program and completed mapping projects are on the internet at https://www.nps.gov/im/vegetation-inventory.htm.

North Carolina, Tennessee↗

USGS2017

A regional assessment of chemicals of concern in surface waters of four Midwestern United States national parks

Anthropogenic chemicals and their potential for adverse biological effects raise concern for aquatic ecosystem health in protected areas. During 2013–15, surface waters of four Midwestern United States national parks were sampled and analyzed for wastewater indicators, pharmaceuticals, personal care products, and pesticides. More chemicals and higher concentrations were detected at the two parks with greater urban influences (Mississippi National River and Recreation Area and Indiana Dunes National Lakeshore) than at the two more remote parks (Apostle Islands National Lakeshore and Isle Royale National Park). Atrazine (10–15 ng/L) and N,N-diethyl-meta-toluamide (16–120 ng/L) were the only chemicals detected in inland lakes of a remote island national park (Isle Royale National Park). Bisphenol A and organophosphate flame retardants were commonly detected at the other sampled parks. Gabapentin and simazine had the highest observed concentrations (> 1000 ng/L) in three and two samples, respectively. At the two parks with urban influences, metolachlor and simazine concentrations were similar to those reported for other major urban rivers in the United States. Environmental concentrations of detected chemicals were often orders of magnitude less than standards or reference values with three exceptions: (1) hydrochlorothiazide exceeded a human health-based screening value in seven samples, (2) estrone exceeded a predicted critical environmental concentration for fish pharmacological effects in one sample, and (3) simazine was approaching the 4000 ng/L Maximum Contaminant Level in one sample even though this concentration is not expected to reflect peak pesticide use. Although few environmental concentrations were approaching or exceeded standards or reference values, concentrations were often in ranges reported to elicit effects in aquatic biota. Data from this study will assist in establishing a baseline for chemicals of concern in Midwestern national parks and highlight the need to better understand the sources, pathways, and potential adverse effects to aquatic systems in national parks.

Indiana, Michigan, Minnesota, Wisconsin↗

USGS2025

Triangulating habitat suitability for the locally extirpated California grizzly bear

Reintroducing locally extirpated wildlife species is often necessary to meet recovery goals. However, because current field data cannot be gathered about these species, efforts to identify suitable habitat are often complicated and controversial. Here we present a case study examining a novel approach for identifying suitable habitat for the locally extirpated brown bear, known as the “grizzly,” in California, USA. Once home to a large population of grizzlies, the last credible sighting of a grizzly in California was in 1924, but recent discussions have explored a reintroduction. To study potential grizzly bear habitat suitability in California, we use a multi-model approach in which we consider three indirect methods, or “analogies,” each of which incorporates both environmental and social variables. In the “historical analogy,” we used a unique record of human encounters and museum specimens to build a habitat model of grizzlies in California 150 years ago. In the “geographic analogy,” we used data about contemporary brown bears in Europe and North America to identify potential suitable habitat in California. In the “taxonomic analogy,” we examined data from other large carnivores currently extant in California to draw conclusions about grizzlies. Because these methods yield varying results, we adopt a process known in the social sciences as “triangulation” to compare them. We show that a triangulation approach can improve our understanding of potential suitable habitat, clarifying the strengths and weaknesses of various methods and producing robust yet conservative estimates. Our findings suggest that large areas of suitable habitat for grizzlies exist in California. However, we note that place-based social science research and long-term investment in co-existence would be necessary to maintain suitability. The “analogy and triangulation” approach demonstrates the value of multi-model approaches for habitat suitability, especially for reintroductions.

California↗

USGS2020

Simulation of discharge, water-surface elevations, and water temperatures for the St. Louis River estuary, Minnesota-Wisconsin, 2016–17

The St. Louis River estuary is a large freshwater estuary, next to Duluth, Minnesota, that encompasses the headwaters of Lake Superior. The St. Louis River estuary is one of the most complex and compromised near-shore systems in the upper Great Lakes with a long history of environmental contamination caused by logging, mining, paper mills, and other heavy industrial activities. Presently (2020), a widely available, science-based assessment tool capable of evaluating ecosystem-level responses to remediation and restoration projects has not existed for the estuary. To address this need, the U.S. Geological Survey (USGS) built a predictive, mechanistic, three-dimensional hydrodynamic model for the estuary using the Environmental Fluid Dynamics Code framework. In the current version, the model can simulate continuous discharge, water-surface elevations, water temperature, and flow velocity, although the modular framework allows for future additions of water-quality modeling. The model was calibrated using data collected from April 2016 through November 2016 and validated with data collected from April 2017 through November 2017. The four types of data used to evaluate model performance were water-surface elevations, discharge, water temperature, and flow velocities. Streamflow and temperature boundary condition data included a mixture of USGS streamgage data, Minnesota Department of Natural Resources gage data, and estimates derived from the gage data. The model was able to simulate the water-surface elevations with generally good agreement between the simulated and measured values for both years at the daily time step. Specifically, the model was able to demonstrate excellent agreement with the measured data with Nash-Sutcliffe efficiency coefficients greater than 0.8 for all three locations; however, the model was unable to produce hourly water-surface elevations with such accuracy for 2016–17. Discharge was more dynamic than the water-surface elevations, both for the measured and simulated data. Generally, most of the discharge ranged from −650 to 1,200 cubic meters per second, but the constantly changing flux exiting the estuary into Lake Superior (positive flows) and entering the estuary from Lake Superior (negative flows) occurred throughout the year. Even upstream at the St. Louis River at Oliver, Wisconsin, gage (USGS station 0402403250), the effect of flows into the estuary from Lake Superior did occur, demonstrating the strong effect of the Lake Superior seiche on flows for the estuary. From a performance standpoint, the model was able to simulate discharge with generally good agreement in both years, although the 2017 validation was better than the 2016 calibration period. For the daily Nash-Sutcliffe efficiency coefficients, the simulated values were 0.98, 0.62, 0.49, and 0.71 for the Oliver gage; the Superior Bay entry channel at Superior, Wisc., (USGS station 464226092005600); the Superior Bay Duluth Ship Canal at Duluth, Minn., (USGS station 464646092052900); and total entries (combination of the Superior entry and Duluth entry), respectively. For the hourly evaluation criteria, the model performed poorly, with Nash-Sutcliffe efficiency coefficients less than 0 for the two entries into Lake Superior; therefore, as a predictor of discharge at the hourly scale, the model performed worse than using the measured data average. Similar to discharge, the model was a good predictor of flow velocity at the daily time scale but had difficulty matching the measured data at the hourly scale. For discharge and flow velocity, matching at subdaily time steps for a system as complicated as the St. Louis River estuary is considered difficult because the match is highly sensitive to coordinating the exact measurement location to the simulated value. The final calibration target was water temperature, calibrated for the Oliver gage and the Duluth entry. For calibration purposes, the Duluth entry was the more important water temperature target because the Oliver gage was more of an internal check on the model. The Nash-Sutcliffe efficiency coefficients for the Duluth entry were high; hourly Nash-Sutcliffe efficiency coefficients at the Duluth entry were either at or greater than 0.7 for both years, and daily values were 0.84 and 0.82 for 2016 and 2017, respectively.

Minnesota, Wisconsin↗

USGS2026

Assessment of groundwater quantity and quality contributions to Lake Huron

Lake Huron, one of the five Great Lakes, borders the United States and Canada, with Michigan as the only U.S. State on its shoreline. Like other freshwater lakes, it faces water-quality challenges from nutrients and chemicals applied across its drainage basin. Although past studies focused on surface-water sources, groundwater contributions remain less understood. To address this gap, the U.S. Geological Survey, as part of the Cooperative Science and Monitoring Initiative, classified drainage basins to Lake Huron into eight hydrogeologic zones based on bedrock rock type and glacial sediment transmissivity. Utilizing existing data and empirical field data, we quantified groundwater discharge and identified areas of concern for loading of chloride and nitrate to Lake Huron. Groundwater contributions, including indirect and shoreline discharge, ranged from 5.8 to 11.5 inches annually, totaling 1.9 cubic miles and 0.09 cubic mile, respectively. Hydrogeologic zones with higher glacial sediment transmissivity yielded greater indirect groundwater discharge. Chloride levels above the U.S. Environmental Protection Agency’s 250-mg/L recommendation were mainly in the Saginaw lowlands, whereas nitrate above the 10-mg/L standard was rare—found in only 11 wells. Together, the analysis of where groundwater discharge is occurring in the Lake Huron Basin and the identification of areas with potential groundwater-quality concerns can help prioritize areas that are critical to protecting the long-term health of Lake Huron.

Michigan↗

USGS2021

Inclusion of pesticide transformation products is key to estimating pesticide exposures and effects in small U.S. streams

Improved analytical methods can quantify hundreds of pesticide transformation products (TPs), but understanding of TP occurrence and potential toxicity in aquatic ecosystems remains limited. We quantified 108 parent pesticides and 116 TPs in more than 3 700 samples from 442 small streams in mostly urban basins across five major regions of the United States. TPs were detected nearly as frequently as parents (90 and 95% of streams, respectively); 102 TPs were detected at least once and 28 were detected in >20% samples in at least one region—TPs of 9 herbicides, 2 fungicides (chlorothalonil and thiophanate-methyl), and 1 insecticide (fipronil) were the most frequently detected. TPs occurred commonly during baseflow conditions, indicating chronic environmental TP exposures to aquatic organisms and the likely importance of groundwater as a TP source. Hazard quotients based on acute aquatic-life benchmarks for invertebrates and nonvascular plants and vertebrate-centric molecular endpoints (sublethal effects) quantify the range of the potential contribution of TPs to environmental risk and highlight several TP exposure–response data gaps. A precautionary approach using equimolar substitution of parent benchmarks or endpoints for missing TP benchmarks indicates that potential aquatic effects of pesticide TPs could be underestimated by an order of magnitude or more.

Environmental Science and Technology↗