Search USGS⌕ Search

SEARCH · Search USGS

Results for “Environmental Conservation”

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

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

At least 397 records · Page 22Linked to original sources
USGS2014

Supplemental feeding alters migration of a temperate ungulate

Conservation of migration requires information on behavior and environmental determinants. The spatial distribution of forage resources, which migration exploits, often are altered and may have subtle, unintended consequences. Supplemental feeding is a common management practice, particularly for ungulates in North America and Europe, and carryover effects on behavior of this anthropogenic manipulation of forage are expected in theory, but have received limited empirical evaluation, particularly regarding effects on migration. We used global positioning system (GPS) data to evaluate the influence of winter feeding on migration behavior of 219 adult female elk (Cervus elaphus) from 18 fed ranges and 4 unfed ranges in western Wyoming. Principal component analysis revealed that the migratory behavior of fed and unfed elk differed in distance migrated, and the timing of arrival to, duration on, and departure from summer range. Fed elk migrated 19.2 km less, spent 11 more days on stopover sites, arrived to summer range 5 days later, resided on summer range 26 fewer days, and departed in the autumn 10 days earlier than unfed elk. Time-to-event models indicated that differences in migratory behavior between fed and unfed elk were caused by altered sensitivity to the environmental drivers of migration. In spring, unfed elk migrated following plant green-up closely, whereas fed elk departed the feedground but lingered on transitional range, thereby delaying their arrival to summer range. In autumn, fed elk were more responsive to low temperatures and precipitation events, causing earlier departure from summer range than unfed elk. Overall, supplemental feeding disconnected migration by fed elk from spring green-up and decreased time spent on summer range, thereby reducing access to quality forage. Our findings suggest that ungulate migration can be substantially altered by changes to the spatial distribution of resources, including those of anthropogenic origin, and that management practices applied in one season may have unintended behavioral consequences in subsequent seasons.

Wyoming↗
USGS2023

Fishes of Harney Basin revisited: An assessment of the distribution of native and nonnative fishes over a half century

The Harney Basin is Oregon's largest internally draining basin and contains a unique native fish assemblage. The first and only comprehensive study of the origin and distribution of Harney Basin fishes occurred in 1971. Here, we update this study and identify potential threats to the basin's native fishes a half century later. Our assessment documents that all species of native fishes are still present, and with some exceptions distributed as originally reported. The distinctive fish assemblages in each of the 3 major subbasins within the Harney Basin (Silvies River, Silver Creek, and Donner und Blitzen River) support the hypothesis that terminal lakes in the Harney Basin (Malheur, Mud, and Harney Lakes) act as dispersal barriers, at least for native species. More than half of the fish species in the basin at present are introduced, primarily inhabiting low-elevation sites. We suggest that native non-salmonid species cohabiting these sites face the most immediate threats from climate change, water demands, and impacts from introduced fishes. Overall, our results show that native fish are still relatively widespread across the Harney Basin, but also face increasing threats despite the basin having experienced less development than many other areas in the Pacific Northwest. Improved understanding of the unique fishes of the Harney Basin, along with more detailed assessments of likely future trajectories of environmental risks are proactive measures that could improve conservation outcomes.

Oregon↗
USGS2011

Groundwater quality of the Gulf Coast aquifer system, Houston, Texas, 2010

During March–December 2010, the U.S. Geological Survey, in cooperation with the city of Houston, collected source-water samples from 60 municipal supply wells in the Houston area. These data were collected as part of an ongoing study to determine concentrations, spatial extent, and associated geochemical conditions that might be conducive for mobility and transport of selected naturally occurring contaminants (selected trace elements and radionuclides) in the Gulf Coast aquifer system in the Houston area. In the summers of 2007 and 2008, a reconnaissance-level survey of these constituents in untreated water from 28 municipal supply wells was completed in the Houston area. Included in this report are the complete analytical results for 47 of the 60 samples collected in 2010—those results which were received from the laboratories and reviewed by the authors as of December 31, 2010. All of the wells sampled were screened in the Gulf Coast aquifer system; 22 were screened entirely in the Evangeline aquifer, and the remaining 25 wells contained screened intervals that intersected both Evangeline and Chicot aquifers. The data documented in this report were collected as part of an ongoing study to characterize source-water-quality conditions in untreated groundwater prior to drinking-water treatment. An evaluation of contaminant occurrence in source water provides background information regarding the presence of a contaminant in the environment. Because source-water samples were collected prior to any treatment or blending that potentially could alter contaminant concentrations, the water-quality results documented by this report represent the quality of the source water, not the quality of finished drinking water provided to the public. Samples were analyzed for major ions (calcium, magnesium, potassium, sodium, bromide, chloride, fluoride, silica, and sulfate), residue on evaporation (dissolved solids), trace elements (arsenic, barium, boron, chromium, iron, lithium, manganese, molybdenum, selenium, strontium, and vanadium), and selected radionuclides (gross alpha- and beta-particle activity [at 72 hours and 30 days], carbon-14, radium-226, radon-222, and uranium). Field measurements were made of selected physicochemical (relating to both physical and chemical) properties (oxidation-reduction potential, turbidity, dissolved-oxygen concentration, pH, specific conductance, water temperature, and alkalinity) and unfiltered sulfides. Similar to the results from the reconnaissance survey, physicochemical properties, major ions, and trace elements varied considerably. The ranges of selected physicochemical properties were as follows: oxidation-reduction potential ranged from -173 to 466 millivolts, dissolved oxygen ranged from less than 0.1 to 4.4 milligrams per liter, pH ranged from 7.2 to 7.8, specific conductance ranged from 439 to 724 microsiemens per centimeter at 25 degrees Celsius, and alkalinity ranged from 159 to 276 milligrams per liter as calcium carbonate. The largest ranges in concentration for filtered major ion constituents were obtained for cations sodium and calcium and for anions chloride and sulfate. Arsenic concentrations measured in samples from the 47 wells ranged from 1.6 to 23.5 micrograms per liter. The maximum concentration of arsenic (23.5 micrograms per liter) was measured in the source-water sample from well LJ-65-12-328. Quantifiable concentrations of barium, boron, lithium, molybdenum, and strontium were measured in all 47 filtered, source-water samples. Quantifiable concentrations of manganese were measured in 46 source-water samples, and an estimated concentration of manganese was measured in 1 sample. Chromium, iron, selenium, and vanadium were detected in 24 or more of the 47 source-water samples. Gross alpha-particle activities and beta-particle activities for all 47 samples were analyzed at 72 hours after sample collection and again at 30 days after sample collection, allowing for the measurement of the activity of short-lived isotopes. Gross alpha-particle activities reported in this report were not adjusted for activity contributions by radon or uranium and, therefore, are conservatively high estimates if compared to the U.S. Environmental Protection Agency National Primary Drinking Water Regulation for adjusted gross alpha-particle activity. The gross alpha-particle activities at 30 days in the samples ranged from R0.60 to 25.5 picocuries per liter and at 72 hours ranged from 2.58 to 39.7 picocuries per liter, and the "R" preceding the value of 0.60 picocuries per liter refers to a nondetected result less than the sample-specific critical level. Gross beta-particle activities measured at 30 days ranged from 1.17 to 14.4 picocuries per liter and at 72 hours ranged from 1.97 to 4.4 picocuries per liter. Filtered uranium was detected in quantifiable amounts in all of the 47 wells sampled. The uranium concentrations ranged from 0.03 to 42.7 micrograms per liter. One sample was analyzed for carbon-14, and the amount of modern atmospheric carbon was reported as 0.2 percent. Six source-water samples collected from municipal supply wells were analyzed for radium-226, and all of the concentrations were considered detectable concentrations (greater than their associated sample-specific critical level). Three source-water samples collected were analyzed for radon-222, and all of the concentrations were substantially greater than the associated sample-specific critical level.

Texas↗
USGS2007

Remotely Sensed Data Collections: Offerings from EROS

The U.S. Geological Survey (USGS) Center for Earth Resources Observation and Science (EROS) maintains a wide variety of remotely sensed data collections that contain a wealth of information about the Earth’s land surfaces. Acquired by special sensors carried aboard civilian satellites and aircraft, the images and other data in these collections provide a unique perspective of the terrestrial environment. They represent invaluable resources for scientists, resource managers, policy makers, and educators to use in studying such things as natural hazards, conservation issues, land use and economic development, and environmental change at local, regional, and global levels. Different types of sensors record different types of information, resulting in diverse data products, each with its own particular strengths. Highlighted here are eight remotely sensed data collections that are currently available from EROS.

Fact Sheet↗
USGS2014

The National Map hydrography data stewardship: what is it and why is it important?

The National Hydrography Dataset (NHD) and Watershed Boundary Dataset (WBD) were designed and populated by a large consortium of agencies involved in hydrography across the United States. The effort was led by the U.S. Geological Survey (USGS), the U.S. Environmental Protection Agency (EPA), and the Natural Resources Conservation Service (NRCS). The high-resolution NHD dataset, completed in 2007, is based on the USGS 7.5-minute series topographic maps at a scale of 1:24,000. There are now 26 million features in the NHD representing a 7.5 million mile stream network with over 6.5 million waterbodies. The six-level WBD, completed in 2010, is based on 1:24,000 scale data and contains over 23,000 watershed polygons. The NHD’s flow network, attribution, and linear referencing are used to conduct extensive scientific analyses. The NHD is ideal for cartographic applications such as the US Topo topographic map series, and also is available on the Geospatial Platform, which provides shared and trusted geospatial data, services, and applications for use by government agencies, their partners, and the public. The WBD watersheds are used by scientists and managers to identify discrete drainage areas. The ongoing maintenance of the NHD and WBD is essential for improving these datasets to meet the ever increasing demand for currency, additional detail, and more significant attribution. The best source of information about changes in local hydrography are users closest to the data, such as State and local governments, as well as Federal land management agencies, and other users of the data. The need for local knowledge has led to the creation of a collaborative data stewardship process to revise and maintain the NHD.

Fact Sheet↗
USGS2021

A river of change—The Rio Grande in the Big Bend region

The Big Bend region is located within the heart of the Chihuahan Desert of North America. Within this region, the Rio Grande, referred to as the Rio Bravo in Mexico, is the international border between the United States and Mexico. The area known as the Big Bend is named after the large northerly bend that the river makes before flowing southeast to the Gulf of Mexico. This region is environmentally protected by both countries. Although large binational conservation efforts exist, the physical and ecological characteristics of the river have been substantially altered. Changes in Rio Grande hydrology (the seasonality, magnitude, duration, and variability in streamflow) have resulted in the widespread physical transformation of the river, resulting in the loss of important habitat for native and endangered fish and increased flood risk. U.S. Geological Survey (USGS) scientists, in cooperation with many other government agencies, universities, and non-governmental organizations (NGOs), are working to better understand these changes to inform management of the Rio Grande.

Texas↗
USGS1996

Hydrogeology and ground-water quality of the chromic acid pit site, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation, in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was certified closed in 1989 and the Texas Natural Resources Conservation Commission issued Permit Number HW-50296 (U.S. Environmental Protection Agency Permit Number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in evaluating hydrogeologic conditions and ground- water quality at the site. One upgradient and two downgradient ground-water monitoring wells were installed adjacent to the chromic acid pit by a private contractor. Quarterly ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The Chromic Acid Pit site is situated in the Hueco Bolson intermontane valley. The Hueco Bolson is a primary source of ground water in the El Paso area. City of El Paso and U.S. Army water-supply wells are located on all sides of the study area and are completed 600 to more than 1,200 feet below land surface. The ground-water level in the area of the Chromic Acid Pit site has declined about 25 feet from 1982 to 1993. Depth to water at the Chromic Acid Pit site in September 1994 was about 284 feet below land surface; ground-water flow is to the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site contained dissolved-solids concentrations of 442 to 564 milligrams per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.7 milligrams per liter; nitrite plus nitrate as nitrogen concentrations ranged from 2.3 to 3.0 milligrams per liter. Nitrate concentrations are abnormally high in the Old Mesa well field located about 5,000 feet southwest of the Chromic Acid Pit site. Volatile and semivolatile organic compounds in water samples were analyzed for the first sampling round; no confirmed volatile or semivolatile organic compounds were detected above the laboratory reporting limits. Total chromium concentrations ranged from 0.0099 to 0.092 milligram per liter; dissolved chromium concentrations ranged from 0.0068 to 0.0094 milligram per liter. Overall, water-quality characteristics in water from the chromic acid pit ground-water monitoring wells are similar to those in the surrounding area. Detected chemical concentrations in water from the chromic acid pit monitoring wells during the four sampling periods were below U.S. Environmental Protection Agency-established maximum contaminant levels for public drinking water supplies. Statistical analyses were performed on 39 of the chemical constituents analyzed for in ground water from the chromic acid pit monitoring wells. Concentrations of chloride and fluoride were significantly less in water from the downgradient wells than in water from the upgradient well, whereas concentrations of nitrate as nitrogen, nitrite plus nitrate as nitrogen, and dissolved solids were significantly greater in water from the downgradient wells than in water from the upgradient well. Concentrations of nitrate as nitrogen were significantly different in water from the two downgradient wells. Differences detected through statistical analysis of chemical constituents of water in the chromic acid pit monitoring wells did not appear to indicate a release of hazardous chemicals from the chromic acid pit. There was no indication of ground-water contamination in either downgradient well.

Texas↗
USGS1996

Ground-water quality, water year 1995, and statistical analysis of ground-water-quality data, water years 1994-95, at the chromic acid pit site, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso, Texas

The Chromic Acid Pit site is an inactive waste disposal site that is regulated by the Resource Conservation and Recovery Act of 1976. The 2.2-cubic-yard cement-lined pit was operated from 1980 to 1983 by a contractor to the U.S. Army Air Defense Artillery Center and Fort Bliss. The pit, located on the Fort Bliss military reservation in El Paso, Texas, was used for disposal and evaporation of chromic acid waste generated from chrome plating operations. The site was closed in 1989, and the Texas Natural Resources Conservation Commission issued permit number HW-50296 (U.S. Environmental Protection Agency number TX4213720101), which approved and implemented post-closure care for the Chromic Acid Pit site. In accordance with an approved post-closure plan, the U.S. Geological Survey is cooperating with the U.S. Army in monitoring and evaluating ground-water quality at the site. One upgradient ground-water monitoring well (MW1) and two downgradient ground-water monitoring wells (MW2 and MW3), installed adjacent to the chromic acid pit, are monitored on a quarterly basis. Ground-water sampling of these wells by the U.S. Geological Survey began in December 1993. The ground-water level, measured in a production well located approximately 1,700 feet southeast of the Chromic Acid Pit site, has declined about 29.43 feet from 1982 to 1995. Depth to water at the Chromic Acid Pit site in September 1995 was 284.2 to 286.5 feet below land surface; ground-water flow at the water table is assumed to be toward the southeast. Ground-water samples collected from monitoring wells at the Chromic Acid Pit site during water year 1995 contained dissolved- solids concentrations of 481 to 516 milligrams per liter. Total chromium concentrations detected above the laboratory reporting limit ranged from 0.0061 to 0.030 milligram per liter; dissolved chromium concentrations ranged from 0.0040 to 0.010 milligram per liter. Nitrate as nitrogen concentrations ranged from 2.1 to 2.8 milligrams per liter; nitrite plus nitrate as nitrogen concentrations ranged from 2.4 to 3.2 milligrams per liter. Water samples from wells MW1 and MW2 were analyzed for volatile organic compounds for the first quarter; no confirmed volatile organic compounds were detected above laboratory reporting limits. Detected chemical concentrations in water from the chromic acid pit monitoring wells during the four sampling periods were below U.S. Environmental Protection Agency-established maximum contaminant levels for public drinking-water supplies. Overall, water-quality characteristics of water from the chromic acid pit ground-water monitoring wells are similar to those of other wells in the surrounding area. Statistical analyses were performed on 56 of the chemical constituents analyzed for in ground water from the chromic acid pit monitoring wells. Concentrations of chloride, fluoride, sulfate, and potassium were significantly less in water from one or both downgradient wells than in water from the upgradient well. Concentrations of nitrate as nitrogen, nitrite plus nitrate as nitrogen, and dissolved solids were significantly greater in water from the downgradient wells than in water from the upgradient well. Concentrations of nitrate as nitrogen, chloride, and potassium were significantly different in water from the two downgradient wells. Statistical analysis of chemical constituents in water from the chromic acid pit monitoring wells did not appear to indicate a release of hazardous chemicals from the chromic acid pit. There was no indication of ground-water contamination in either downgradient well.

Texas↗
USGS2018

Development of a species status assessment process for decisions under the U.S. Endangered Species Act

Decisions under the U.S. Endangered Species Act (ESA) require scientific input on the risk that the species will become extinct. A series of critiques on the role of science in ESA decisions have called for improved consistency and transparency in species risk assessments and clear distinctions between science input and policy application. To address the critiques and document the emerging practice of the U.S. Fish and Wildlife Service (USFWS), we outline an assessment process based on principles and practices of risk and decision analyses that results in a scientific report on species status. The species status assessment (SSA) process has three successive stages: 1) document the life history and ecological relationships of the species in question to provide the foundation for the assessment, 2) describe and hypothesize causes for the current condition of the species, and 3) forecast the species' future condition. The future condition refers to the ability of a species to sustain populations in the wild under plausible future scenarios. The scenarios help explore the species' response to future environmental stressors and to assess the potential for conservation to intervene to improve its status. The SSA process incorporates modeling and scenario planning for prediction of extinction risk and applies the conservation biology principles of representation, resiliency, and redundancy to evaluate the current and future condition. The SSA results in a scientific report distinct from policy application, which contributes to streamlined, transparent, and consistent decision-making and allows for greater technical participation by experts outside of the USFWS, for example, by state natural resource agencies. We present two case studies based on assessments of the eastern massasauga rattlesnake Sistrurus catenatus and the Sonoran Desert tortoise Gopherus morafkai to illustrate the process. The SSA builds upon the past threat-focused assessment by including systematic and explicit analyses of a species' future response to stressors and conservation, and as a result, we believe it provides an improved scientific analysis for ESA decisions.

Journal of Fish and Wildlife Management↗
USGS1986

Example evaluation of a permit application for a proposed hazardous-waste landfill in eastern Adams County, Colorado

A project was undertaken by the U.S. Geological Survey in cooperation with the U. S. Environmental Protection Agency to demonstrate methods by which RCRA (Resources Conservation and Recovery Act of 1976) Part B permit applications might be evaluated. The purpose of the project was to prepare a report that would supplement a series of case studies to be made available to permit writers in the U.S. Environmental Protection Agency. Four sites in the United States were chosen for their potential applicability to geologically similar sites. The Adams County, Colorado, site was chosen to be representative of sites in the Upper Cretaceous Pierre Shale. The intent of this report is to provide an example of how available earth-science information might be used in evaluating an application and not to evaluate the acceptability of the site. Because this study is an evaluation of a permit application, the data used are limited to the data supplied in the application and in published reports. Of the five criteria required by the U.S. Environmental Protection Agency to be addressed in the permit application considered in the case study, the application was evaluated to be inadequate in addressing three criteria: (1) Site characterization, (2) ability to monitor the location, and (3) flow paths and 100-foot time of travel. Details of the inadequacies and a description of the information needed to eliminate the inadequacies are included in the report. (USGS)

Water-Resources Investigations Report↗
USGS2010

Monitoring and Evaluation of Environmental Flow Prescriptions for Five Demonstration Sites of the Sustainable Rivers Project

The Nature Conservancy has been working with U.S. Army Corps of Engineers (Corps) through the Sustainable Rivers Project (SRP) to modify operations of dams to achieve ecological objectives in addition to meeting the authorized purposes of the dams. Modifications to dam operations are specified in terms of environmental flow prescriptions that quantify the magnitude, duration, frequency, and seasonal timing of releases to achieve specific ecological outcomes. Outcomes of environmental flow prescriptions implemented from 2002 to 2008 have been monitored and evaluated at demonstration sites in five rivers: Green River, Kentucky; Savannah River, Georgia/South Carolina; Bill Williams River, Arizona; Big Cypress Creek, Texas; and Middle Fork Willamette River, Oregon. Monitoring and evaluation have been accomplished through collaborative partnerships of federal and state agencies, universities, and nongovernmental organizations.

Open-File Report↗
USGS2011

Integrating estimates of ecosystem services from conservation programs and practices into models for decision makers

Most government agencies involved in land management are seeking consistent approaches to evaluate the effects of specific management actions on ecological processes and concurrent changes on ecosystem services. This is especially true within the context of anthropogenic influences, such as land use and climate change. The Conservation Effects Assessment Project—Wetlands National Component (CEAP–Wetlands) was developed by the U.S. Department of Agriculture (USDA) to evaluate effects of conservation practices on ecosystem services including carbon sequestration for climate stability, groundwater recharge, runoff and flood attenuation, water storage, nutrient and contaminant retention, and wildlife habitat. A primary purpose of CEAP–Wetlands is to provide science‐based information in an adaptive monitoring framework for use by the USDA to facilitate policy and management decisions, and to document effects of conservation programs and practices to the federal Office of Management and Budget. Herein, we propose a modeling framework to allow estimation of conservation practice and program effects on various ecosystem services at different temporal and spatial scales. This modeling approach provides the broad view needed by decision‐makers to avoid unintended negative environmental outcomes, and to communicate to society the positive effects of conservation actions on a broad suite of ecosystem services.

Ecological Applications↗
USGS2014

Where the bison roam: public-private partnership supports potential restoration

A little over one hundred years ago, plains bison were prolific in the Great American West. Reports describe herds containing thousands of animals migrating through the central and western states, totaling 20–30 million across their entire range. With commercial, unregulated hunting in the late 1800s came the rapid demise of bison to barely more than 1,000 by 18891. Recently, renewed interest in restoring these massive animals to at least some of their former range has grown. Efforts are being made to establish “conservation herds”—herds that are specifically managed in the public interest by governments and environmental organizations. For the plains bison native to the United States, there are approximately 19,000 animals comprising 54 known conservation herds.

Report↗
USGS2026

Keeping pace: Migrating sea lampreys adjust swim speed in response to shifting water velocity to maintain a constant ground speed

Upstream migrating fish must balance energetic costs with environmental and ecological constraints. Theoretical models predict that fish can conserve energy by adjusting swim speed in response to changing water velocity, but detailed field tests of these predictions remain rare. We used fine-scale acoustic telemetry and hydrodynamic modeling to track adult sea lamprey (Petromyzon marinus) migrating through a river and evaluated how movement speeds varied with environmental conditions and individual traits. Swim speed increased with faster water velocities, while ground speed remained constant, supporting the hypothesis that lampreys regulate swim effort to maintain a fixed migration pace. The average ground speed aligned with a predicted optimum of ∼1 body length per second. Both swim and ground speeds declined slightly in deeper water, suggesting a trade-off between movement efficiency and predator avoidance. These findings provide field-based support for a theoretical model of energy optimization and underscore how migratory fish adaptively adjust behavior to local hydrodynamic conditions. Our results highlight the value of using high-resolution tracking and environmental modeling to reveal behavioral tactics that underlie efficient migration strategies.

Michigan↗
USGS2024

A new era of genetic diversity conservation through novel tools and accessible data

As the foundation of biodiversity, genetic diversity is necessary for species to adapt to ecological changes, such as impacts from disease, invasive species, and climate change. Genetic diversity also supports ecosystem resilience and societal innovations. Unfortunately, declines in genetic diversity have been frequently observed in populations of wild and domestic species. Yet the field of population genetics is often neglected in national and global environmental policy and has been underutilized in biodiversity monitoring and conservation action.

Frontiers in Ecology and the Environment↗
USGS2025

How accurately does eDNA reflect the spatial distribution of cold-water fish? Field validation from a temperate lake

Applications of environmental DNA (eDNA) based detection technology to evaluate the distribution of aquatic organisms are increasing; yet field validations of eDNA are important to measure accuracy in study systems. To successfully apply this technology to species conservation, it is critical to understand how both species biology and environmental conditions affect the accuracy of inference from eDNA detection data. We implemented a field assessment of the accuracy and spatial resolution of eDNA-based species distributions for a native cold-water, schooling fish, cisco Coregonus artedi , that has been reintroduced to a deep temperate lake. We leveraged a combination of acoustic telemetry, providing known spatial locations of tagged fish, and lake-wide eDNA sampling to infer their distribution in Keuka Lake, New York, USA. Sub-surface (12 m and 18 m depths) eDNA samples were collected to accommodate the diel vertical migration behaviour of this fish species. The results of this study validated the accuracy of positive eDNA detections with the distribution of tagged fish to coarse spatial scales. Yet, several fine-scale locations revealed a mismatch between eDNA and acoustic telemetry detections; consistent with rapid transport of genetic material via lake currents. Empirical measurements of lake currents using drifters found cisco eDNA detections could deviate from specimens' source locations by as much as 3.3 km at 12 m depth or 1.5 km at 18 m depth over a 24 h transport period. Our study indicates that accurate species distributions estimated from eDNA sampling in lakes may require further understanding of transport mechanisms and persistence of environmental genetic material to relate point detections to source animal locations. Integrating eDNA sampling with additional data collection of species biology and environmental conditions will increase the spatial resolution of fish distribution assessments.

New York↗
USGS2023

The Government eDNA Working Group 6th Annual eDNA Technical Exchange Workshop

The 6th annual Environmental DNA (eDNA) Technical Exchange Workshop was a virtual workshop hosted and coordinated by the Government eDNA Working Group (GEDWG) on January 24–26, 2023. GEDWG is a no-cost consortium that focuses on bringing together stakeholders associated with federal, state, provincial, municipal, and other government and non-government agencies interested in eDNA and related fields, for the purposes of sharing technical expertise and experience during monthly discussion meetings and annual workshops. Over 400 participants registered for the virtual Workshop, which featured four keynote speakers, 23 platform talks, eight short-form poster presentations, and an extended discussion session. Workshop attendees represented a broad cross-section of disciplines and backgrounds, including research scientists, natural resource managers, and conservation policy experts, and many different government agencies, private environmental consulting firms, trade organizations, non-governmental organizations, and others in the environmental management sector. Key takeaways from the workshop included moving the application of eDNA into resource management and discovering ways to improve policy uptake in the development of nationwide biodiversity monitoring, some of which is happening in the development of eDNA networks and national strategies. Future research directions discussed include studies of fate and transport, autonomous sampling/sample processing, and reference library curation. Additionally, co-design of studies and improved engagement and communication among scientists and managers are needed to ensure clear expectations and outcomes.

Environmental DNA↗
USGS2025

Amphibian diversity of the western Colorado canyonlands including potential threats from nonnative bullfrogs and disease

Throughout the canyons of the Colorado and Uncompahgre Plateaus, water is a limited resource for wildlife, with patchy distribution and seasonal availability. Tributary creeks within these canyons drain into mainstem rivers, providing habitat and breeding sites for native amphibians. Yet, little is known about the diversity and distribution of amphibians that live in these harsh, dynamic environments. In addition, the rivers that border these canyon tributaries may serve as corridors for nonnative species and disease. The American Bullfrog ( Lithobates catesbeianus ) is a nonnative species in western Colorado known to prey on native amphibians and act as a reservoir for pathogens such as Batrachochytrium dendrobatidis ( Bd ). From 2019 to 2022, we surveyed for amphibians using visual encounter surveys (VES) and environmental DNA (eDNA) surveys throughout the McInnis Canyons National Conservation Area (MCNCA), the Dominguez–Escalante National Conservation Area (DENCA), and the Dolores River Canyon Wilderness Study Area (DRCWSA). Our primary goals were to document the diversity and distribution of native amphibians in the canyonlands and evaluate potential threats to these species from bullfrogs and Bd . We confirmed that sensitive species, such as the Great Basin Spadefoot ( Spea intermontana ) and the Northern Leopard Frog ( Lithobates pipiens ), inhabit these protected areas. In most cases, bullfrogs were not detected within ephemeral tributaries, but bullfrog DNA was detected in some tributaries at the confluence with the mainstem rivers. In Mee Canyon (MCNCA), however, bullfrogs were found within the tributary, up to 3 km from the Colorado River. A bullfrog individual removed from this canyon tested positive for Bd , and diet contents suggested that native amphibians are potential prey in this system. Nonnative predators and disease pose a threat to native amphibians, alongside environmental changes such as drought and hydrological shifts driven by ongoing climate change.

Colorado↗