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At least 19 recordsLinked to original sources
USGS2021

Feather corticosterone reveals developmental challenges in a long-term study of juvenile northern spotted owls

Corticosterone is a steroid hormone integral to a variety of physiological pathways and is strongly associated with the vertebrate stress response. In avian species, circulating corticosterone is sequestered into developing feathers and is used as an indicator of energy allocation during feather growth and widely applied in conservation physiology. The northern spotted owl Strix occidentalis caurina is a federally threatened old-growth forest obligate of conservation concern endemic to the Pacific Northwest of the United States and Canada. The effects of landscape characteristics and individual variation on early development in spotted owls remain unstudied despite long recognition of this knowledge gap and its potential importance to species conservation. We quantified corticosterone concentrations in 4,720 feathers from 1,056 juvenile spotted owls across seven study areas between 2001 and 2017. We used an information-theoretic approach to examine the environmental and individual factors related to feather corticosterone in juvenile spotted owls as an indicator of challenges during early development. Feather corticosterone was positively related to temperature and precipitation, and negatively related to juvenile mass at banding. We found strong support for an interaction between mass and precipitation, with greater amounts of precipitation being associated with higher levels of feather corticosterone in lighter juveniles. The temperature and precipitation metric with the strongest relationship with feather corticosterone occurred during the fledging period, suggesting that this period presents an energetic challenge for juvenile spotted owls. Greater juvenile mass decreased the effect of precipitation, suggesting that greater mass was important for juveniles to maintain homeostasis during fledgling. Feather corticosterone in juvenile spotted owls provided insights to the challenges faced during early development, adding to our understanding of spotted owl life history and potential for population recovery.

Oregon, Washington↗
USGS2000

Tissue-specific induction of Hsp90 mRNA and plasma cortisol response in chinook salmon following heat shock, seawater challenge, and handling challenge

In studying the whole-body response of chinook salmon ( Oncorhynchus tshawytscha ) to various stressors, we found that 5-hour exposure to elevated temperature (mean 21.6°C; + 10.6°C over ambient) induced a marked increase in Hsp90 messenger RNA accumulation in heart, brain, gill, muscle, liver, kidney, and tail fin tissues. The most vital tissues (heart, brain, gill, and muscle) showed the greatest Hsp90-mRNA response, with heart tissue increasing approximately 35-fold. Heat shock induced no increase in plasma cortisol. In contrast, a standard handling challenge induced high plasma cortisol levels, but no elevation in Hsp90 mRNA in any tissue, clearly separating the physiological and cellular stress responses. We saw no increase either in tissue Hsp90 mRNA levels or in plasma cortisol concentrations after exposing the fish to seawater overnight.

Marine Biotechnology↗
USGS2013

Challenge theme 2: assuring water availability and quality in the 21st century: Chapter 4 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Along the United States–Mexican border, the health of communities, economies, and ecosystems is inextricably intertwined with the availability and quality of water, but effective water management in the Borderlands is complicated. Water users compete for resources, and their needs are increasing. Managers are faced with issues such as finding a balance between agriculture and rapidly growing cities or maintaining public supplies while ensuring sufficient resources for aquatic ecosystems. In addition to human factors, the dry climate of the Borderlands, as compared to more temperate regions, also increases the challenge of balancing water supplies between humans and ecosystems. Warmer, drier, and more variable conditions across the southwestern United States—the projected results of climate change (Seager and others, 2007)—would further stress water supplies.

United States-Mexico Borderlands↗
USGS2013

Challenge theme 6: Natural hazard risks in the Borderlands: Chapter 8 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Natural hazards such as earthquakes, landslides and debris flows, wildfires, hurricanes, and intense storm-induced flash floods threaten communities to varying degrees all along the United States–Mexican border. The U.S. Geological Survey (USGS) collaborates with Federal, State, and local agencies to minimize the effects of natural hazards by providing timely, unbiased science information to emergency response officials, resource managers, and the public to help reduce property damage, injury, and loss of life. The USGS often mobilizes response efforts during and after a natural hazard event to provide technical and scientific counsel on recovery and response, and it has a long history of deploying emergency response teams to major disasters in both domestic and international locations. This chapter describes the challenges of natural hazards in the United States–Mexican border region and the capabilities of the USGS in the fields of hazard research, monitoring, and assessment, as well as preventative mitigation and post-disaster response.

United States-Mexico Borderlands↗
USGS2013

Challenge theme 7: Information support for management of border security and environmental protection: Chapter 9 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Historically, international borders were located far from the major political and economic capitals of their countries and rarely received adequate planning or infrastructure development. Today, as a result of global economics and increased movement of goods between nations, border regions play a much greater role in commerce, tourism, and transportation. For example, Mexico is the second largest destination for United States exports (Woodrow Wilson Center Mexico Institute, 2009). The rapid population and economic growth along the United States–Mexican border, undocumented human border crossings, and the unique natural diversity of resources in the Borderlands present challenges for border security and environmental protection. Assessing risks and implementing sustainable growth policies to protect the environment and quality of life greatly increase in complexity when the issues cross an international border, where social services, environmental regulations, lifestyles, and cultural beliefs are unique for each country. Shared airsheds, water and biological resources, national security issues, and disaster management needs require an integrated binational approach to assess risks and develop binational management strategies.

United States-Mexico Borderlands↗
USGS2013

Challenge theme 1: Understanding and preserving ecological resources: Chapter 3 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

The notable biodiversity within the United States–Mexican border region is driven by the wide variety of natural landscapes in the area and its biologically unique transition zone of habitats for xeric, temperate, and subtropical species. Six diverse ecoregions cover the length of the border (fig. 3–1): California Coastal Sage, Chaparral, and Oak Woodlands; Sonoran Desert; Madrean Archipelago; Chihuahuan Desert; Southern Texas Plains; and Western Gulf Coastal Plain. The unique geology and many of the distinctive geographic features and climatic conditions that have given rise to the diverse populations of plants and animals found in the Borderlands also attract human populations. The number of people living in the Borderlands has increased dramatically over recent years, from about 7 million in 1980 to almost 12 million in 2003; the population is estimated to be more than 18 million by 2020 (Peach and Williams, 2003). The human population increase and associated change in land use have contributed to habitat fragmentation and habitat loss for native species, thus threatening their survival. Some ways in which humans negatively affect plants and animals in the Borderlands include dewatering of aquatic ecosystems, water pollution, introduction and spread of invasive species, outdoor lighting, military and border enforcement activity, and energy development and transmission.

United States-Mexico Borderlands↗
USGS2013

Challenge theme 3: Protecting the environment and safeguarding human health: Chapter 5 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Many of the diverse, fragile ecosystems of the United States–Mexican border region are reaching unsustainable levels because of rapid population growth and changes in land use. Water shortages and pollution, poor air quality, increased soil salinities, and pesticides and heavy metal contaminants are some of the many stressors that are degrading the quality of life in the Borderlands. Lack of water treatment and wastewater infrastructure on both sides of the United States–Mexican border contributes to elevated rates of various communicable diseases most commonly found in developing countries: tuberculosis, intestinal infections, and hepatitis. Chronic diseases (diabetes, cancer, and heart disease) also prevail at high rates along the border, resembling trends observed in developed countries. In addition, the subtropical climate of the Borderlands is particularly suited for vectors of tropical diseases, such as malaria and dengue fever.

United States-Mexico Borderlands↗
USGS2013

Challenge theme 4: People in the Borderlands: Chapter 6 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

The management of shared resources in the United States–Mexican border region requires cooperation from the people of both countries to assess and understand their relation to the environment. Society is dependent on the long-term healthy functioning of ecosystems and their ability to supply food and raw materials. Likewise, resources and services obtained from nature could be used efficiently within the society. A more equitable distribution of costs and benefits related to goods and services can lead to fewer tensions and a higher quality of life for all the people in the Borderlands. Urban development, background contamination from mineral ore deposits, irrigation, sewage effluent, and even global climate change all have the potential to alter the stability of the fragile systems in the Borderlands (Brady and others, 2001, 2002; Norman, 2007, 2010; Gu and others, 2008; Norman, Gray, and others, 2008; Norman, Hirsch, and Ward, 2008; Norman, Callegary, and others, 2010; Norman, Huth, and others, 2010; Norman, Levick, and others, 2010; Norman, Tallent-Halsell, and others, 2010; Norman, Villarreal, and others 2012). Social efficiency means that because resources should be used where they are needed most, they should be distributed proportionally among human societies and individuals (Azar and others, 1996). Despite the critical role natural resources play in maintaining human and environmental health, current knowledge of the manner in which natural and human-caused forces interact to limit these resources—including their quality and quantity (such as through spatiotemporal changes in precipitation, evapotranspiration, pumping of groundwater, and release of contaminants)—is inadequate. The U.S. Geological Survey (USGS) is trying to understand the relation between changing landscapes, changing demographics, and a changing climate in the Borderlands while the environmental, economic, and societal issues continue to be intertwined between the two nations.

United States-Mexico Borderlands↗
USGS2013

Challenge theme 5: Current and future needs of energy and mineral resources in the Borderlands and the effects of their development: Chapter 7 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Exploration and extraction activities related to energy and mineral resources in the Borderlands—such as coal-fired power plants, offshore drilling, and mining—can create issues that have potentially major economic and environmental implications. Resource assessments and development projects, environmental studies, and other related evaluations help to understand some of these issues, such as power plant emissions and the erosion/denudation of abandoned mine lands. Information from predictive modeling, monitoring, and environmental assessments are necessary to understand the full effects of energy and mineral exploration, development, and utilization. The exploitation of these resources can negatively affect human health and the environment, its natural resources, and its ecological services (air, water, soil, recreation, wildlife, etc.). This chapter describes the major energy and mineral issues of the Borderlands and how geologic frameworks, integrated interdisciplinary (geobiologic) investigations, and other related studies can address the anticipated increases in demands on natural resources in the region.

United States-Mexico Borderlands↗
USGS2013

United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

Along the nearly 3,200 kilometers (almost 2,000 miles) of the United States–Mexican border, in an area known as the Borderlands, we are witnessing the expression of the challenges of the 21st century. This circular identifies several challenge themes and issues associated with life and the environment in the Borderlands, listed below. The challenges are not one-sided; they do not originate in one country only to become problems for the other. The issues and concerns of each challenge theme flow in both directions across the border, and both nations feel their effects throughout the Borderlands and beyond. The clear message is that our two nations, the United States and Mexico, face the issues in these challenge themes together, and the U.S. Geological Survey (USGS) understands it must work with its counterparts, partners, and customers in both countries. Though the mission of the USGS is not to serve as land manager, law enforcer, or code regulator, its innovation and creativity and the scientific and technical depth of its capabilities can be directly applied to monitoring the conditions of the landscape. The ability of USGS scientists to critically analyze the monitored data in search of signals and trends, whether they lead to negative or positive results, allows us to reach significant conclusions—from providing factual conclusions to decisionmakers, to estimating how much of a natural resource exists in a particular locale, to predicting how a natural hazard phenomenon will unfold, to forecasting on a scale from hours to millennia how ecosystems will behave. None of these challenge themes can be addressed strictly by one or two science disciplines; all require well-integrated, cross-discipline thinking, data collection, and analyses. The multidisciplinary science themes that have become the focus of the USGS mission parallel the major challenges in the border region between Mexico and the United States. Because of this multidisciplinary approach, the USGS possesses a unique set of capabilities that can address these challenges. The USGS can apply geographical, geospatial, biological, hydrological, and geological sciences to these complex issues and thereby provide insight into the area’s natural systems and their relation to human activity. As we come to better understand the complexities of the components of these challenge themes, we discover that each part is inextricably intertwined with other overarching issues. Because of the complex interactions of the human, ecological, political, and economic exigencies associated with this area, the status of the Borderlands has become an ever-present concern for most American citizens and for Mexican and United States Federal, State, and local governments. This circular is intended to provide you - citizen, local decisionmaker, government leader, or private entrepreneur—an overview of what the USGS considers the current and future challenges in the United States–Mexican border region and examples of how the USGS can make a difference in understanding and addressing these issues.

United States-Mexico Borderlands↗
USGS2017

Grand challenges for integrated USGS science — A workshop report

Executive Summary The U.S. Geological Survey (USGS) has a long history of advancing the traditional Earth science disciplines and identifying opportunities to integrate USGS science across disciplines to address complex societal problems. The USGS science strategy for 2007–2017 laid out key challenges in disciplinary and interdisciplinary arenas, culminating in a call for increased focus on a number of crosscutting science directions. Ten years on, to further the goal of integrated science and at the request of the Executive Leadership Team (ELT), a workshop with three dozen invited scientists spanning different disciplines and career stages in the Bureau convened on February 7–10, 2017, at the USGS John Wesley Powell Center for Analysis and Synthesis in Fort Collins, Colorado. The workshop focused on identifying “grand challenges” for integrated USGS science. Individual participants identified nearly 70 potential grand challenges before the workshop and through workshop discussions. After discussion, four overarching grand challenges emerged: Natural resource security, Societal risk from existing and emerging threats, Smart infrastructure development, and Anticipatory science for changing landscapes. Participants also identified a “comprehensive science challenge” that highlights the development of integrative science, data, models, and tools—all interacting in a modular framework—that can be used to address these and other future grand challenges: Earth Monitoring, Analyses, and Projections (EarthMAP) EarthMAP is our long-term vision for an integrated scientific framework that spans traditional scientific boundaries and disciplines, and integrates the full portfolio of USGS science: research, monitoring, assessment, analysis, and information delivery. The Department of Interior, and the Nation in general, have a vast array of information needs. The USGS meets these needs by having a broadly trained and agile scientific workforce. Encouraging and supporting cross-discipline engagement would position the USGS to tackle complex and multifaceted scientific and societal challenges in the 21st Century.

Open-File Report↗
USGS2015

Computational fluid dynamics-habitat suitability index (CFD-HSI) modelling as an exploratory tool for assessing passability of riverine migratory challenge zones for fish

We developed two-dimensional computational fluid hydraulics-habitat suitability index (CFD-HSI) models to identify and qualitatively assess potential zones of shallow water depth and high water velocity that may present passage challenges for five major anadromous fish species in a 2.63-km reach of the main stem Penobscot River, Maine, as a result of a dam removal downstream of the reach. Suitability parameters were based on distribution of fish lengths and body depths and transformed to cruising, maximum sustained and sprint swimming speeds. Zones of potential depth and velocity challenges were calculated based on the hydraulic models; ability of fish to pass a challenge zone was based on the percent of river channel that the contiguous zone spanned and its maximum along-current length. Three river flows (low: 99.1 m 3 sec -1 ; normal: 344.9 m 3 sec -1 ; and high: 792.9 m 3 sec -1 ) were modelled to simulate existing hydraulic conditions and hydraulic conditions simulating removal of a dam at the downstream boundary of the reach. Potential depth challenge zones were nonexistent for all low-flow simulations of existing conditions for deeper-bodied fishes. Increasing flows for existing conditions and removal of the dam under all flow conditions increased the number and size of potential velocity challenge zones, with the effects of zones being more pronounced for smaller species. The two-dimensional CFD-HSI model has utility in demonstrating gross effects of flow and hydraulic alteration, but may not be as precise a predictive tool as a three-dimensional model. Passability of the potential challenge zones cannot be precisely quantified for two-dimensional or three-dimensional models due to untested assumptions and incomplete data on fish swimming performance and behaviours.

River Research and Applications↗
USGS2024

Glucocorticoid and glycemic responses to immune challenge in a viviparous snake afflicted with an emerging mycosis

Disease may be both a cause and consequence of stress, and physiological responses to infectious disease may involve stress coping mechanisms that have important fitness consequences. For example, glucocorticoid and glycemic responses may affect host fitness by altering resource allocation and use in hosts, and these responses may be affected by competing stressors. To better understand the factors that affect host responses to infection, we challenged the immune system of field acclimatized pygmy rattlesnakes, Sistrurus miliarius , with a sterile antigen, lipopolysaccharide (LPS), and measured the glucocorticoid and glycemic response in healthy non-reproductive snakes, snakes afflicted with an emerging mycosis (ophidiomycosis), and pregnant snakes. We hypothesized that LPS challenge would result in a glucocorticoid and glycemic response typical of the vertebrate acute phase response (APR), and therefore predicted that LPS challenge would result in an acute increase in plasma corticosterone (CORT) and a decline in plasma glucose in all individuals. Additionally, we hypothesized that the APR would be attenuated in individuals simultaneously coping with additional challenges to homeostasis (i.e., disease or reproduction). As predicted, immune challenge elicited an acute increase in plasma CORT and a decrease in plasma glucose. Snakes coping with ophidiomycosis and pregnant snakes were able to mount a robust glucocorticoid and hypoglycemic response to LPS challenge, which was contrary to our hypothesis. Our findings clarify directions of causality linking infection, glucocorticoids, and glucose, and emphasize the importance of future research examining the fitness consequences of interactions between stress and disease in wildlife threatened by emerging pathogens.

Journal of Experimental Biology↗
USGS1986

Infectious pancreatic necrosis virus: Protocol for a standard challenge to brook trout

A protocol for experimental challenge with infectious pancreatic necrosis (IPN) virus was defined with brook trout Salvelinus fontinalis as the model species. Fish were exposed by immersion for 5 h in water containing IPN virus at a concentration of 10 5 plaque‐forming units per milliliter. We propose the protocol as a standard challenge based on our studies of exposure methods and host response to virulent virus. Immersion challenge induced higher and more consistent mortality than did challenge by hyperosmotic infiltration. Challenge virus should be sequentially transferred no more than five times in cell culture because further transfers reduced the virulence of the virus. At 12°C, mortalities due to primary infection occurred 6–12 d after immersion challenge and were highest (≥70%) in fish 27–56 d old. Susceptibility to lethal infection was enhanced by nutritional stress.

Transactions of the American Fisheries Society↗
USGS2009

USGS Science: Addressing Our Nation's Challenges

With 6.6 billion people already living on Earth, and that number increasing every day, human influence on our planet is ever more apparent. Changes to the natural world combined with increasing human demands threaten our health and safety, our national security, our economy, and our quality of life. As a planet and a Nation, we face unprecedented challenges: loss of critical and unique ecosystems, the effects of climate change, increasing demand for limited energy and mineral resources, increasing vulnerability to natural hazards, the effects of emerging diseases on wildlife and human health, and growing needs for clean water. The time to respond to these challenges is now, but policymakers and decisionmakers face difficult choices. With competing priorities to balance, and potentially serious - perhaps irreversible - consequences at stake, our leaders need reliable scientific information to guide their decisions. As the Nation's earth and natural science agency, the USGS monitors and conducts scientific research on natural hazards and resources and how these elements and human activities influence our environment. Because the challenges we face are complex, the science needed to better understand and deal with these challenges must reflect the complex interplay among natural and human systems. With world-class expertise in biology, geology, geography, hydrology, geospatial information, and remote sensing, the USGS is uniquely capable of conducting the comprehensive scientific research needed to better understand the interdependent interactions of Earth's systems. Every day, the USGS helps decisionmakers to minimize loss of life and property, manage our natural resources, and protect and enhance our quality of life. This brochure provides examples of the challenges we face and how USGS science helps decisionmakers to address these challenges.

General Information Product↗
USGS2025

Overcoming challenges in mapping hydrography and heterogeneity in urban landscapes

Understanding how water moves through a watershed is one of the most fundamental yet often complicated aspects of hydrology, especially in urban areas. Urban infrastructure and water management alter natural hydrological pathways in developed watersheds, which can violate assumptions of a watershed approach to ecosystem science. We focus on two aspects of urban landscapes that often create challenges to model watershed processes within and among urban areas: (1) accurate delineation of urban flow paths and (2) consistent characterisation of the urban landscape within and among cities. Here, we describe these challenges and identify how certain components of these challenges can be addressed, highlighting examples and lessons learned in a project that is assessing scales and drivers of variability in dissolved organic carbon across five urban centres in the United States. Our goal is to facilitate a dialogue that will advance the applications of watershed approaches in urban ecosystem science by recognising and addressing these challenges. Our examples focus on the United States but could be applicable to similar urban challenges in other locations globally.

Florida, Massachusetts, Utah↗
USGS2024

Considerations and challenges in support of science and communication of fish consumption advisories for per- and polyfluoroalkyl substances

Federal, state, tribal, or local entities in the United States issue fish consumption advisories (FCAs) as guidance for safer consumption of locally caught fish containing contaminants. Fish consumption advisories have been developed for commonly detected compounds such as mercury and polychlorinated biphenyls. The existing national guidance does not specifically address the unique challenges associated with bioaccumulation and consumption risk related to per- and polyfluoroalkyl substances (PFAS). As a result, several states have derived their own PFAS-related consumption guidelines, many of which focus on one frequently detected PFAS, known as perfluorooctane sulfonic acid (PFOS). However, there can be significant variation between tissue concentrations or trigger concentrations (TCs) of PFOS that support the individual state-issued FCAs. This variation in TCs can create challenges for risk assessors and risk communicators in their efforts to protect public health. The objective of this article is to review existing challenges, knowledge gaps, and needs related to issuing PFAS-related FCAs and to provide key considerations for the development of protective fish consumption guidance. The current state of the science and variability in FCA derivation, considerations for sampling and analytical methodologies, risk management, risk communication, and policy challenges are discussed. How to best address PFAS mixtures in the development of FCAs, in risk assessment, and establishment of effect thresholds remains a major challenge, as well as a source of uncertainty and scrutiny. This includes developments better elucidating toxicity factors, exposures to PFAS mixtures, community fish consumption behaviors, and evolving technology and analytical instrumentation, methods, and the associated detection limits. Given the evolving science and public interests informing PFAS-related FCAs, continued review and revision of FCA approaches and best practices are vital. Nonetheless, consistent, widely applicable, PFAS-specific approaches informing methods, critical concentration thresholds, and priority compounds may assist practitioners in PFAS-related FCA development and possibly reduce variability between states and jurisdictions. Integr Environ Assess Manag 2024;00:1–20. © 2024 SETAC

Integrated Environmental Assessment and Management↗
USGS2023

Challenges and solutions for automated avian recognition in aerial imagery

Remote aerial sensing provides a non-invasive, large geographical-scale technology for avian monitoring, but the manual processing of images limits its development and applications. Artificial Intelligence (AI) methods can be used to mitigate this manual image processing requirement. The implementation of AI methods, however, has several challenges: (1) imbalanced (i.e., long-tailed) data distribution, (2) annotation uncertainty in categorization, and (3) dataset discrepancies across different study sites. Here we use aerial imagery data of waterbirds around Cape Cod and Lake Michigan in the United States to examine how these challenges limit avian recognition performance. We review existing solutions and demonstrate as use cases how methods like Label Distribution Aware Marginal Loss with Deferred Re-Weighting, hierarchical classification, and FixMatch address the three challenges. We also present a new approach to tackle the annotation uncertainty challenge using a Soft-fine Pseudo-Label methodology. Finally, we aim with this paper to increase awareness in the ecological remote sensing community of these challenges and bridge the gap between ecological applications and state-of-the-art computer science, thereby opening new doors to future research.

Remote Sensing in Ecology and Conservation↗