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At least 361 records · Page 20Linked to original sources
USGS2020

Spatiotemporal variation in occurrence and co-occurrence of pesticides, hormones, and other organic contaminants in rivers in the Chesapeake Bay Watershed, United States

Investigating the spatiotemporal dynamics of contaminants in surface water is crucial to better understand how introduced chemicals are interacting with and potentially influencing aquatic organisms and environments. Within the Chesapeake Bay Watershed, USA, there are concerns about the potential role of contaminant exposure on fish health. Evidence suggests that exposure to contaminants in surface water is causing immunosuppression and intersex in freshwater fish species. Despite these concerns, there is a paucity of information regarding the complex dynamics of contaminant occurrence and co-occurrence in surface water across both space and time. To address these concerns, we applied a Bayesian hierarchical joint-contaminant model to describe the occurrence and co-occurrence patterns of 28 contaminants and total estrogenicity across six river sites and over three years. We found that seasonal occurrence patterns varied by contaminant, with the highest occurrence probabilities during the spring and summer months. Additionally, we found that the proportion of agricultural landcover in the immediate catchment, as well as stream discharge, did not have a significant effect on the occurrence probabilities of most compounds. Four pesticides (atrazine, metolachlor, fipronil and simazine) co-occurred across sites after accounting for environmental covariates. These results provide baseline information on the contaminant occurrence patterns of several classes of compounds within the Chesapeake Bay Watershed. Understanding the spatiotemporal dynamics of contaminants in surface water is the first step in investigating the effects of contaminant exposure on fisheries and aquatic environments.

Delaware, Maryland, New York, Pennsylvania, Virgin↗
USGS2013

2011 floods of the central United States

The Central United States experienced record-setting flooding during 2011, with floods that extended from headwater streams in the Rocky Mountains, to transboundary rivers in the upper Midwest and Northern Plains, to the deep and wide sand-bedded lower Mississippi River. The U.S. Geological Survey (USGS), as part of its mission, collected extensive information during and in the aftermath of the 2011 floods to support scientific analysis of the origins and consequences of extreme floods. The information collected for the 2011 floods, combined with decades of past data, enables scientists and engineers from the USGS to provide syntheses and scientific analyses to inform emergency managers, planners, and policy makers about life-safety, economic, and environmental-health issues surrounding flood hazards for the 2011 floods and future floods like it. USGS data, information, and scientific analyses provide context and understanding of the effect of floods on complex societal issues such as ecosystem and human health, flood-plain management, climate-change adaptation, economic security, and the associated policies enacted for mitigation. Among the largest societal questions is "How do we balance agricultural, economic, life-safety, and environmental needs in and along our rivers?" To address this issue, many scientific questions have to be answered including the following: * How do the 2011 weather and flood conditions compare to the past weather and flood conditions and what can we reasonably expect in the future for flood magnitudes? * What is the “natural” hydrology of these watersheds and how have they been changed? * How do rivers change during floods and what effects do they have on the natural and built environment: conversely, what effects do the natural and built environments have on rivers and floods? * Do floods contribute to the transport and fate of contaminants that affect human and ecosystem health? In an effort to help address these and other questions, USGS Professional Paper 1798 consists of independent but complementary chapters dealing with various scientific aspects of the 2011 floods in the Central United States.

Professional Paper↗
USGS2013

Mapping monkeypox transmission risk through time and space in the Congo Basin

Monkeypox is a major public health concern in the Congo Basin area, with changing patterns of human case occurrences reported in recent years. Whether this trend results from better surveillance and detection methods, reduced proportions of vaccinated vs. non-vaccinated human populations, or changing environmental conditions remains unclear. Our objective is to examine potential correlations between environment and transmission of monkeypox events in the Congo Basin. We created ecological niche models based on human cases reported in the Congo Basin by the World Health Organization at the end of the smallpox eradication campaign, in relation to remotely-sensed Normalized Difference Vegetation Index datasets from the same time period. These models predicted independent spatial subsets of monkeypox occurrences with high confidence; models were then projected onto parallel environmental datasets for the 2000s to create present-day monkeypox suitability maps. Recent trends in human monkeypox infection are associated with broad environmental changes across the Congo Basin. Our results demonstrate that ecological niche models provide useful tools for identification of areas suitable for transmission, even for poorly-known diseases like monkeypox.

PLoS ONE↗
USGS2002

Worldwide occurrences of arsenic in ground water

Numerous aquifers worldwide carry soluble arsenic at concentrations greater than the World Health Organization--and U.S. Environmental Protection Agency--recommended drinking water standard of 10 mg per liter. Sources include both natural (black shales, young sediments with low flushing rates, gold mineralization, and geothermal environments) and anthropogenic (mining activities, livestock feed additives, pesticides, and arsenic trioxide wastes and stockpiles). Increased solubility and mobility of arsenic is promoted by high pH (>8.5), competing oxyanions, and reducing conditions. In this Policy Forum, Nordstrom argues that human health risks from arsenic in ground water can be minimized by incorporating hydrogeochemical knowledge into water management decisions and by more careful monitoring for arsenic in geologically high-risk areas.

Science↗
USGS2007

Biological conditions in streams of Johnson County, Kansas, and nearby Missouri, 2003 and 2004

Johnson County is one of the fastest growing and most populated counties in Kansas. Urban development affects streams by altering stream hydrology, geomorphology, water chemistry, and habitat, which then can lead to adverse effects on fish and macroinvertebrate communities. In addition, increasing sources of contaminants in urbanizing streams results in public-health concerns associated with exposure to and consumption of contaminated water. Biological assessments, or surveys of organisms living in aquatic environments, are crucial components of water-quality programs because they provide an indication of how well water bodies support aquatic life. This fact sheet describes current biological conditions of Johnson County streams and characterizes stream biology relative to urban development. Biological conditions were evaluated by collecting macroinvertebrate samples from 15 stream sites in Johnson County, Kansas, in 2003 and 2004 (fig. 1). Data from seven additional sites, collected as part of a separate study with similar objectives in Kansas and Missouri (Wilkison and others, 2005), were evaluated to provide a more comprehensive assessment of watersheds that cross State boundaries. Land-use and water- and streambed-sediment-quality data also were used to evaluate factors that may affect macroinvertebrate communities. Metrics are indices used to measure, or evaluate, macroinvertebrate response to various factors such as human disturbance. Multimetric scores, which integrated 10 different metrics that measure various aspects of macroinvertebrate communities, including organism diversity, composition, tolerance, and feeding characteristics, were used to evaluate and compare biological health of Johnson County streams. This information is useful to city and county officials for defining current biological conditions, evaluating conditions relative to State biological criteria, evaluating effects of urbanization, developing effective water-quality management plans, and documenting changes in biological conditions and water quality.

Kansas, Missouri↗
USGS2013

Pathways of coupled arsenic and iron cycling in high arsenic groundwater of the Hetao basin, Inner Mongolia, China: an iron isotope approach

High As groundwater is widely distributed all over the world, which has posed a significant health impact on millions of people. Iron isotopes have recently been used to characterize Fe cycling in aqueous environments, but there is no information on Fe isotope characteristics in the groundwater. Since groundwater As behavior is closely associated with Fe cycling in the aquifers, Fe isotope signatures may help to characterize geochemical processes controlling As concentrations of shallow groundwaters. This study provides the first observation of Fe isotope fractionation in high As groundwater and evaluation of Fe cycling and As behaviors in shallow aquifers in terms of Fe isotope signatures. Thirty groundwater samples were taken for chemical and isotopic analysis in the Hetao basin, Inner Mongolia. Thirty-two sediments were sampled as well from shallow aquifers for Fe isotope analysis. Results showed that groundwater was normally enriched in isotopically light Fe with δ 56 Fe values between −3.40‰ and 0.58‰ and median of −1.14‰, while heavier δ 56 Fe values were observed in the sediments (between −1.10‰ and 0.75‰, median +0.36‰). In reducing conditions, groundwaters generally had higher δ 56 Fe values, in comparison with oxic conditions. High As groundwaters, generally occurring in reducing conditions, had high δ 56 Fe values, while low As groundwaters normally had low δ 56 Fe values. Although sediment δ 56 Fe values were generally independent of lithological conditions, a large variation in sediment δ 56 Fe values was observed in the oxidation–reduction transition zone. Three pathways were identified for Fe cycling in shallow groundwater, including dissimilatory reduction of Fe(III) oxides, re-adsorption of Fe(II), and precipitation of pyrite and siderite. Dissimilatory reduction of Fe(III) oxides resulted in light δ 56 Fe values (around −1.0‰) and high As concentration (>50 μg/L) in groundwater in anoxic conditions. Re-adsorption of isotopically heavy Fe(II) produced by microbially mediated reduction of Fe(III) oxides led to further enrichment of isotopically light Fe in groundwater (up to −3.4‰ of δ 56 Fe) in anoxic–suboxic conditions. Arsenic re-adsorption was expected to occur along with Fe(II) re-adsorption, decreasing groundwater As concentrations. In strongly reducing conditions, precipitation of isotopically light Fe-pyrite and/or siderite increased groundwater δ 56 Fe values, reaching +0.58‰ δ 56 Fe, with a subsequent decrease in As concentrations via co-precipitation. The mixed effect of those pathways would regulate As and Fe cycling in most groundwaters.

Inner Mongolia↗
USGS2002

Interspecific interactions in trematode communities

This chapter reviews the behavioural ecology of trematodes, focusing on intramolluscular stages. Interspecific competitive interactions, their frequency, dominance hierarchies and resolutions are discussed. Strategies employed by larval trematode species to adapt to a hostile, competitive environment, how these adaptations shape larval trematode communities, and how altered trematode communities can affect ecosystems and human health are reviewed.

Book chapter↗
USGS2010

Groundwater flow systems at the Nevada Test Site, Nevada: A synthesis of potentiometric contours, hydrostratigraphy, and geologic structures

Contaminants introduced into the subsurface of the Nevada Test Site by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a series of contour maps developed to represent the hydraulic-head distribution within each of the major aquifers underlying the area. Aquifers were identified and their extents delineated by merging and analyzing multiple hydrostratigraphic framework models developed by other investigators from existing geologic information. A map of the hydraulic-head distribution in each major aquifer was developed from a detailed evaluation and assessment of available water-level measurements. Multiple spreadsheets that accompany this report provide pertinent water-level and geologic data by well or drill hole. Aquifers are mapped and discussed in general terms as being one of two types: alluvial–volcanic, or carbonate. Both aquifer types are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater-flow directions, approximated from potentiometric contours that were developed from the hydraulic-head distribution, are indicated on the maps and discussed for each of the regional aquifers and for selected local aquifers. Hydraulic heads vary across the study area and are interpreted to range in altitude from greater than 5,000 feet in a regional alluvial–volcanic aquifer beneath a recharge area in the northern part of the study area to less than 2,300 feet in regional alluvial–volcanic and carbonate aquifers in the southwestern part of the study area. Flow directions throughout the study area are dominantly south-southwest with some local deviations. Vertical hydraulic gradients between aquifer types are downward throughout most of the study area; however, flow from the alluvial–volcanic aquifer into the underlying carbonate aquifer, where both aquifers are present, is believed to be minor because of an intervening confining unit. Limited exchange of water between aquifer types occurs by diffuse flow through the confining unit, by focused flow along fault planes, or by direct flow where the confining unit is locally absent. Interflow between regional aquifers is evaluated and mapped to define major flow paths. These flow paths delineate tributary flow systems, which converge to form intermediate and regional flow systems. The implications of these flow systems in controlling transport of radionuclides away from the underground test areas at the Nevada Test Site are briefly discussed. Additionally, uncertainties in the delineation of aquifers, the development of potentiometric contours, and the identification of flow systems are identified and evaluated. Eleven tributary flow systems and three larger flow systems are mapped in the Nevada Test Site area. Flow systems within the alluvial–volcanic aquifer dominate the western half of the study area, whereas flow systems within the carbonate aquifer are most prevalent in the southeastern half of the study area. Most of the flow in the regional alluvial–volcanic aquifer that moves through the underground testing area on Pahute Mesa is discharged to the land surface at springs and seeps in Oasis Valley. Flow in the regional carbonate aquifer is internally compartmentalized by major geologic structures, primarily thrust faults, which constrain flow into separate corridors. Contaminants that reach the regional carbonate aquifer from testing areas in Yucca and Frenchman Flats flow toward downgradient discharge areas through the Alkali Flat–Furnace Creek Ranch or Ash Meadows flow systems and their tributaries.

Nevada↗
USGS2012

Conceptualization of the predevelopment groundwater flow system and transient water-level responses in Yucca Flat, Nevada National Security Site, Nevada

Contaminants introduced into the subsurface of Yucca Flat, Nevada National Security Site, by underground nuclear testing are of concern to the U.S. Department of Energy and regulators responsible for protecting human health and safety. The potential for contaminant movement away from the underground test areas and into the accessible environment is greatest by groundwater transport. The primary hydrologic control on this transport is evaluated and examined through a set of contour maps developed to represent the hydraulic-head distribution within the two major aquifer systems underlying the area. Aquifers and confining units within these systems were identified and their extents delineated by merging and analyzing hydrostratigraphic framework models developed by other investigators from existing geologic information. Maps of the hydraulic-head distributions in the major aquifer systems were developed from a detailed evaluation and assessment of available water-level measurements. The maps, in conjunction with regional and detailed hydrogeologic cross sections, were used to conceptualize flow within and between aquifer systems. Aquifers and confining units are mapped and discussed in general terms as being one of two aquifer systems: alluvial-volcanic or carbonate. The carbonate aquifers are subdivided and mapped as independent regional and local aquifers, based on the continuity of their component rock. Groundwater flow directions, approximated from potentiometric contours, are indicated on the maps and sections and discussed for the alluvial-volcanic and regional carbonate aquifers. Flow in the alluvial-volcanic aquifer generally is constrained by the bounding volcanic confining unit, whereas flow in the regional carbonate aquifer is constrained by the siliceous confining unit. Hydraulic heads in the alluvial-volcanic aquifer typically range from 2,400 to 2,530 feet and commonly are elevated about 20-100 feet above heads in the underlying regional carbonate aquifer. Flow directions in the alluvial-volcanic aquifer are variable and are controlled by localized areas where small amounts of water can drain into the regional carbonate aquifer. These areas commonly are controlled by geologic structures, such as Yucca fault. Flow in the regional carbonate aquifer generally drains to the center of the basin; from there flow is to the south-southeast out of the study area toward downgradient discharge areas. Southward flow in the regional carbonate aquifer occurs in a prominent potentiometric trough that results from a faulted zone of enhanced permeability centered about Yucca fault. Vertical hydraulic gradients between the aquifer systems are downward throughout the study area; however, flow from the alluvial-volcanic aquifer into the underlying carbonate aquifer is believed to be minor because of the intervening confining unit. Transient water levels were identified and analyzed to understand hydraulic responses to stresses in Yucca Flat. Transient responses have only a minimal influence on the general predevelopment flow directions in the aquifers. The two primary anthropogenic stresses on the groundwater system since about 1950 are nuclear testing and pumping. Most of the potentiometric response in the aquifers to pumping or past nuclear testing is interim and localized. Persistent, long-lasting changes in hydraulic head caused by nuclear testing occur only in confining units where groundwater fluxes are negligible. A third stress on the groundwater system is natural recharge, which can cause minor, short- and long-term changes in water levels. Long-term hydrographs affected by natural recharge, grouped by similar trend, cluster in distinct areas of Yucca Flat and are controlled primarily by spatial differences in local recharge patterns.

Nevada↗
USGS2025

Identifying gaps in regulatory prevention measures for nonindigenous aquatic species in the United States

Nonindigenous aquatic species (NAS) present in trade can become costly invaders once introduced and established in a new environment. Preventing NAS introduction is considered the most effective strategy to avoid potential negative ecological, economic, and human health impacts associated with certain species. The United States government enacts regulatory prevention measures carried out by numerous federal agencies with designated authority over certain species, taxonomic groups, and pathways of introduction. We examined 18 case study species across eight taxonomic groups and eight pathways of introduction using a gap analysis approach to identify current gaps in regulatory prevention that may hinder the United States from achieving a more “ideal state” of management in which no NAS or pathways of introduction are unregulated. We found that outside of pathway regulations for ballast water and biofouling, the majority of amphibian, fish, reptile, crustacean, and mollusk species are subject to little to no regulation aside from a few specific species that are highly regulated. We also found large knowledge gaps surrounding the diversity of species and quantities of individual organisms introduced into the United States through the hitchhiking and cultural release pathways. We highlight that the current regulatory approach in the United States is a “blocklist” approach where a select list of species is disallowed as compared to an “allowlist” (approved list of species allowed only) or “conditional list” (between a “blocklist” and “allowlist”) used by Australia and New Zealand. Increased documentation of the diversity and quantities of NAS entering the United States and a better understanding of the contribution of the hitchhiking and cultural release pathways to NAS introductions could help inform regulatory prevention.

Management of Biological Invasions↗
USGS2021

Emergent biogeochemical risks from Arctic permafrost degradation

The Arctic cryosphere is collapsing, posing overlapping environmental risks. In particular, thawing permafrost threatens to release biological, chemical and radioactive materials that have been sequestered for tens to hundreds of thousands of years. As these constituents re-enter the environment, they have the potential to disrupt ecosystem function, reduce the populations of unique Arctic wildlife and endanger human health. Here, we review the current state of the science to identify potential hazards currently frozen in Arctic permafrost. We also consider the cascading natural and anthropogenic processes that may compound the impacts of these risks, as it is unclear whether the highly adapted Arctic ecosystems have the resilience to withstand new stresses. We conclude by recommending research priorities to address these underappreciated risks.

Nature Climate Change↗
USGS2012

Parasite invasion following host reintroduction: a case of Yellowstone’s wolves

Wildlife reintroductions select or treat individuals for good health with the expectation that these individuals will fare better than infected animals. However, these individuals, new to their environment, may also be particularly susceptible to circulating infections and this may result in high morbidity and mortality, potentially jeopardizing the goals of recovery. Here, using the reintroduction of the grey wolf (Canis lupus) into Yellowstone National Park as a case study, we address the question of how parasites invade a reintroduced population and consider the impact of these invasions on population performance. We find that several viral parasites rapidly invaded the population inside the park, likely via spillover from resident canid species, and we contrast these with the slower invasion of sarcoptic mange, caused by the mite Sarcoptes scabiei. The spatio-temporal patterns of mange invasion were largely consistent with patterns of host connectivity and density, and we demonstrate that the area of highest resource quality, supporting the greatest density of wolves, is also the region that appears most susceptible to repeated disease invasion and parasite-induced declines. The success of wolf reintroduction appears not to have been jeopardized by infectious disease, but now shows signs of regulation or limitation modulated by parasites.

Wyoming↗
USGS2022

Continuous water-quality and suspended-sediment transport monitoring in San Francisco Bay, California, water years 2020–21

The U.S. Geological Survey (USGS) has continuously monitored real-time water quality and suspended-sediment transport in San Francisco Bay (the Bay) since 1989 as part of a multi-agency effort (see “Acknowledgments” section) to address estuary management, water supply, and ecological concerns. The San Francisco Bay area is home to millions of people and biologically diverse marine and terrestrial flora and fauna. Freshwater mixes with saltwater in the Bay and is subject to riverine influences (floods, droughts, managed reservoir releases, and freshwater diversions) and marine influences (tides, waves, and effects of saltwater). Water temperature, salinity, suspended-sediment concentration (SSC), and turbidity, are used by State and Federal resources managers and are monitored at eight key locations throughout the Bay (fig. 1). Water temperature and salinity affect the density of water, which controls gravity-driven circulation patterns and stratification in the water column. Salinity indicates the relative mixing of fresh and ocean waters in the Bay and is derived from specific conductance measurements. Turbidity is a measure of light scattered from suspended particles in the water that is used to estimate suspended-sediment concentration. Suspended-sediment concentrations also are directly measured through depth-integrated water sampling. Suspended sediment affects Bay water quality in multiple ways. Suspended sediment affects phytoplankton growth by attenuating sunlight in the water column. Suspended sediment deposition on tidal marshes and intertidal mudflats helps to restore and sustain these habitats as sea level rises. Settling of suspended sediment in ports and shipping channels creates the need for more dredging. In addition, suspended sediment often carries adsorbed contaminants as it is transported in the water column, which affects the distributions and concentrations of adsorbed contaminants in the environment. Excessive concentrations of sediment-adsorbed contaminants in deposits on the bottom of the Bay can affect ecosystem health. External factors, such as tidal currents, waves, and wind can also affect water quality in the Bay. Tidal currents in the Bay change direction four times daily, and wind direction and intensity typically fluctuate on a daily cycle. Consequently, salinity, water temperature, and suspended-sediment concentration differ spatially and temporally throughout the Bay. Therefore, high-frequency measurements at multiple locations are needed to monitor these changes. Data collected at eight stations throughout the Bay are transmitted in near real-time using cellular telemetry and posted to the USGS National Water Information System (NWIS; https://waterdata.usgs.gov/usa/nwis ). The purposes of this fact sheet are to (1) provide information about the USGS San Francisco Bay water-quality monitoring network; (2) highlight various applications in which these data can be used; and (3) provide internet links to access the resulting continuous water-quality data collected by the USGS.

California↗
USGS2012

The U.S. Geological Survey Ecosystem Science Strategy, 2012-2022 - Advancing discovery and application through collaboration

Ecosystem science is critical to making informed decisions about natural resources that can sustain our Nation’s economic and environmental well-being. Resource managers and policy-makers are faced with countless decisions each year at local, state, tribal, territorial, and national levels on issues as diverse as renewable and non-renewable energy development, agriculture, forestry, water supply, and resource allocations at the urban-rural interface. The urgency for sound decision-making is increasing dramatically as the world is being transformed at an unprecedented pace and in uncertain directions. Environmental changes are associated with natural hazards, greenhouse gas emissions, and increasing demands for water, land, food, energy, mineral, and living resources. At risk is the Nation’s environmental capital, the goods and services provided by resilient ecosystems that are vital to the health and well-being of human societies. Ecosystem science—the study of systems of organisms interacting with their environment and the consequences of natural and human-induced change on these systems—is necessary to inform decision-makers as they develop policies to adapt to these changes. This Ecosystems Science Strategy is built on a framework that includes basic and applied science. It highlights the critical roles that USGS scientists and partners can play in building scientific understanding and providing timely information to decision-makers. The strategy underscores the connection between scientific discoveries and the application of new knowledge. The strategy integrates ecosystem science and decision-making, producing new scientific outcomes to assist resource managers and providing public benefits. The USGS is uniquely positioned to play an important role in ecosystem science. With its wide range of expertise, the agency can bring holistic, cross-scale, interdisciplinary capabilities to the design and conduct of monitoring, research, and modeling and to new technologies for data collection, management, and visualization. Collectively, these capabilities can be used to reveal ecological patterns and processes, explain how and why ecosystems change, and forecast change over different spatial and temporal scales. USGS science can provide managers with options and decision-support tools to use resources sustainably. The USGS has long-standing, collaborative relationships with the DOI and other partners in the natural sciences, in both conducting science and its application. The USGS engages these partners in cooperative investigations that otherwise would lack the necessary support or be too expensive for a single bureau to conduct. The heart of this strategy is a framework and vision for USGS ecosystems science that focuses on five long-term goals, which are seen as interconnected and reinforcing components: • Improve understanding of ecosystem structure, function, and processes. The focus for this goal is an understanding of how ecosystems work, including the dynamics of species, their populations, interactions, and genetics, and how they change across spatial and temporal scales. • Advance understanding of how drivers influence ecosystem change. The challenges here are explaining the drivers of ecosystem change, their spatio-temporal patterns, their uncertainties and interactions, and their influence on ecosystem processes and dynamics. • Improve understanding of the services that ecosystems provide to society. Here the emphasis is on the measurement of environmental capital and ecosystem services, and the identification of sources and patterns of change in space and time. • Develop tools, technologies, and capacities to inform decision-making about ecosystems. This includes developing new technologies and approaches for conducting applications-oriented ecosystem science. A principal challenge will be how to quantify uncertainty and incorporate it in decision analysis. • Apply science to enhance strategies for management, conservation, and restoration of ecosystems. These challenges include development of novel approaches to monitoring, assessment, and restoration of ecosystems; new methods to address species of concern and communities at risk; and innovations in decision analysis and support to address imminent ecosystem changes or those that are underway. Closely integrated with the five goals are four strategic approaches that provide the path forward for the USGS Ecosystems Mission Area. These approaches cross-cut all of the goals and are seen as essential to the implementation of this strategy: • Assess information needs for ecosystem science through enhanced partnerships. Work with the DOI and other agencies and institutions to identify, design, and implement priority decision-driven ecological research. • Promote the use of interdisciplinary ecosystem science. Design and conduct interdisciplinary process-oriented research in ecosystem science. • Enhance modeling and forecasting. Build models to forecast ecosystem change, assess future management scenarios, and reduce uncertainties through an adaptive learning process. • Support decision-making. Use quantitative approaches to assess the vulnerabilities of ecosystems, habitats, and species, and evaluate strategies for adaptation, restoration, and sustainable management. Following the strategic approaches are a set of proposed actions that represent a sampling of specific activities that align with this strategy and that address the Nation’s most pressing environmental needs. The strategy emphasizes coordination of activities across the USGS mission areas pursuant to these goals. Ecosystem science is inherently interdisciplinary and requires a broad perspective that incorporates the biological and physical sciences, climate science, information technology, and scientific capacity in mission areas across the Bureau. With its emphasis on coordination, this strategy can provide a critical underpinning for integrated science efforts with scientists from multiple mission areas of the USGS working together. Of course, the USGS will continue to conduct both discipline-specific and interdisciplinary investigations, and both will continue to be vital parts of the ecosystem science portfolio. Finally, the strategy stresses the importance of coordination with other Federal agencies and organizations in the natural resources community. The USGS collaborates with resource agencies in the DOI and other organizations throughout the world to meet societal needs for species and ecosystem management. Working with these agencies and organizations, the USGS will play a key role over the next decade in advancing the scientific foundation for sustaining the natural resources that diverse, productive, resilient ecosystems provide.

Open-File Report↗
USGS2016

Changing levels of heavy metal accumulation in birds at Tumacacori National Historic Park along the Upper Santa Cruz River Watershed in southern Arizona

National Parks and other protected areas can be influenced by contamination from outside their boundaries. This is particularly true of smaller parks and those in riparian ecosystems, a habitat that in arid environments provides critical habitat for breeding, migratory, and wintering birds. Animals living in contaminated areas are susceptible to adverse health effects as a result of long-term exposure and bioaccumulation of heavy metals. We investigated the distribution and cascading extent of heavy metal accumulation in Song Sparrows (Melospiza melodia) at Tumacacori National Historic Park (TUMA) along the upper Santa Cruz River watershed in southern Arizona. This study had three goals: (1) quantify the concentrations and distributional patterns of heavy metals in blood and feathers of Song Sparrows at Tumacacori National Historic Park, (2) quantify hematocrit values, body conditions (that is, residual body mass), and immune conditions of Song Sparrows in the park (3) compare our findings with prior studies at the park to assess the extent of heavy metal accumulation in birds at downstream sites after the 2009 wastewater treatment plant upgrade, and (4) quantify concentrations and distributional patterns of heavy metals in blood and feathers of Song Sparrows among six study sites throughout the upper Santa Cruz River watershed. This study design would allow us to more accurately assess song sparrow condition and blood parameters among sites with differing potential sources of contamination exposure, and how each location could have contributed to heavy metal levels of birds in the park.

Conference Paper↗
USGS2018

Alaska

Alaska is the largest state in the Nation, almost one-fifth the size of the combined lower 48 United States, and is rich in natural capital resources. Alaska is often identified as being on the front lines of climate change since it is warming faster than any other state and faces a myriad of issues associated with a changing climate. The cost of infrastructure damage from a warming climate is projected to be very large, potentially ranging from $110 to $270 million per year, assuming timely repair and maintenance. Although climate change does and will continue to dramatically transform the climate and environment of the Arctic, proactive adaptation in Alaska has the potential to reduce costs associated with these impacts. This includes the dissemination of several tools, such as guidebooks to support adaptation planning, some of which focus on Indigenous communities. While many opportunities exist with a changing climate, economic prospects are not well captured in the literature at this time. As the climate continues to warm, there is likely to be a nearly sea ice-free Arctic during the summer by mid-century. Ocean acidification is an emerging global problem that will intensify with continued carbon dioxide (CO 2 ) emissions and negatively affects organisms. Climate change will likely affect management actions and economic drivers, including fisheries, in complex ways. The use of multiple alternative models to appropriately characterize uncertainty in future fisheries biomass trajectories and harvests could help manage these challenges. As temperature and precipitation increase across the Alaska landscape, physical and biological changes are also occurring throughout Alaska’s terrestrial ecosystems. Degradation of permafrost is expected to continue, with associated impacts to infrastructure, river and stream discharge, water quality, and fish and wildlife habitat. Longer sea ice-free seasons, higher ground temperatures, and relative sea level rise are expected to exacerbate flooding and accelerate erosion in many regions, leading to the loss of terrestrial habitat in the future and in some cases requiring entire communities or portions of communities to relocate to safer terrain. The influence of climate change on human health in Alaska can be traced to three sources: direct exposures, indirect effects, and social or psychological disruption. Each of these will have different manifestations for Alaskans when compared to residents elsewhere in the United States. Climate change exerts indirect effects on human health in Alaska through changes to water, air, and soil and through ecosystem changes affecting disease ecology and food security, especially in rural communities. Alaska’s rural communities are predominantly inhabited by Indigenous peoples who may be disproportionately vulnerable to socioeconomic and environmental change; however, they also have rich cultural traditions of resilience and adaptation. The impacts of climate change will likely affect all aspects of Alaska Native societies, from nutrition, infrastructure, economics, and health consequences to language, education, and the communities themselves. The profound and diverse climate-driven changes in Alaska’s physical environment and ecosystems generate economic impacts through their effects on environmental services. These services include positive benefits directly from ecosystems (for example, food, water, and other resources), as well as services provided directly from the physical environment (for example, temperature moderation, stable ground for supporting infrastructure, and smooth surface for overland transportation). Some of these effects are relatively assured and in some cases are already occurring. Other impacts are highly uncertain, due to their dependence on the structure of global and regional economies and future human alterations to the environment decades into the future, but they could be large. In Alaska, a range of adaptations to changing climate and related environmental conditions are underway and others have been proposed as potential actions, including measures to reduce vulnerability and risk, as well as more systemic institutional transformation.

Report↗
USGS2006

Parasitism and body condition in humpback chub from the Colorado and Little Colorado Rivers, Grand Canyon, Arizona

Glen Canyon Dam has greatly altered the Colorado River in Grand Canyon. The Little Colorado River (LCR) provides a small refuge of seasonally warm and turbid water that is thought to be more suitable than the Colorado River for endangered humpback chub Gila cypha. However, the LCR has low productivity and contains nonnative fishes and parasites, which pose a threat to humpback chub. The Colorado River hosts a different suite of nonnative fishes and is cold and clear but more productive. We compared condition factor (K), abdominal fat index (AFI), and presence and number of two introduced pathogenic parasites (Lernaea cyprinacea and Bothriocephalus acheilognathi) between juvenile (<150 mm total length) humpback chub from the LCR and those from the Colorado River during 1996a??1999. Both K and AFI were lower and L. cyprinacea prevalence and B. acheilognathi prevalence were higher in LCR fish than in Colorado River fish for all years. Mean K and AFI were 0.622 and 0.48, respectively, in the LCR and 0.735 and 2.02, respectively, in the Colorado River, indicating that fish in the Colorado River were more robust. Mean prevalence of L. cyprinacea was 23.9% and mean intensity was 1.73 L. cyprinacea/infected fish in the LCR, whereas prevalence was 3.2% and intensity was 1.0 L. cyprinacea/infected fish in the Colorado River. Mean prevalence of B. acheilognathi was 51.0% and mean intensity was 25.0 B. acheilognathi/infected fish in the LCR, whereas prevalence was 15.8% and intensity was 12.0 B. acheilognathi/infected fish in the Colorado River. Increased parasitism and poorer body condition in humpback chub from the LCR challenge the paradigm that warmer LCR waters are more suitable for humpback chub than the colder Colorado River and indicate the need to consider the importance and benefits of all available habitats, as well as biotic and abiotic factors, when managing endangered species and their environment.

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