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At least 181 records · Page 10Linked to original sources
USGS2023

Fish life-history traits predict abundance-occupancy patterns in artificial lakes

Life-history traits of a species have been postulated as a factor in abundance and occupancy patterns. Understanding how traits contribute to the ubiquity and rarity of taxa can facilitate the development of effective conservation policy by establishing a connection between species requirements and resource. The goal was to evaluate fish assemblages in artificial lakes for evidence of the abundance-occupancy patterns reported in natural environments and, if evident, to explore if observed patterns of abundance and occupancy could be attributed to species traits. Fish abundance and occupancy were estimated over 1990–2018 in 22 artificial lakes impounded within the Tennessee River basin, USA. Consistent with reports for many other taxonomic groups in natural environments, there was a positive association amidst 114 fish species between abundance and occupancy in artificial lakes ( R 2 = 0.78). This result indicates that the fish assemblages that develop in these anthropized environments follow the fundamental abundance-occupancy patterns uncovered in natural environments, despite assemblages having been disfigured by the dramatic rearrangement of habitats brought by impoundment. Moreover, a redundancy analysis focusing mostly on reproductive and habitat traits adequately predicted abundance-occupancy patterns of fish assemblages in artificial lakes ( R 2 = 0.69). Species abundance-occupancy is influenced by the interplay between life-history traits and habitat availability, even in artificial lakes, and by extension, possibly other artificial ecosystems.

Alabame, Georgia, Kentucky, Mississippi, North Car↗
USGS2009

Unearthing Secrets of the Forest

Forests are a defining feature for large areas of the Pacific northwestern United States from northern California to Alaska. Coniferous temperate rainforests in the western Cascade and coastal mountain ranges are appreciated for their aesthetic value and abundant natural resources. Few people recognize the riches beneath the forest floor; yet, soil is a key ecosystem component that makes each type of forest unique. Soils harbor immense biological diversity and control the release of water and nutrients that support life above ground. Understanding how carbon and nutrients cycle in forests, known as forest biogeochemistry, is crucial for evaluating forest productivity, composition, diversity, and change. At the U.S. Geological Survey (USGS) Forest and Rangeland Ecosystem Science Center, research in the Terrestrial Ecosystems Laboratory focuses on nutrient cycling in five themes: climate change, nutrition and sustainability, fire effects, restoration, and forest-stream linkages. This research is essential to understand the entire forest ecosystem and to use the best science available to make informed policy and management decisions.

Fact Sheet↗
USGS2011

The USA National Phenology Network; taking the pulse of our planet

People have tracked phenology for centuries and for the most practical reasons: it helped them know when to hunt and fish, when to plant and harvest crops, and when to navigate waterways. Now phenology is being used as a tool to assess climate change and its effects on both natural and modified ecosystems. How is the timing of events in plant and animal life cycles, like flowering or migration, responding to climate change? And how are those responses, in turn, affecting people and ecosystems? The USA National Phenology Network (the Network) is working to answer these questions for science and society by promoting a broad understanding of plant and animal phenology and their relationship to environmental change. The Network is a consortium of organizations and individuals that collect, share, and use phenology data, models, and related information to enable scientists, resource managers, and the public to adapt in response to changing climates and environments. In addition, the Network encourages people of all ages and backgrounds to observe and record phenology as a way to discover and explore the nature and pace of our dynamic world. The National Coordinating Office (NCO) of the Network is a resource center that facilitates and encourages widespread collection, integration, and sharing of phenology data and related information (for example, meteorological and hydrological data). The NCO develops and promotes standardized methods for field data collection and maintains several online user interfaces for data upload and download, as well as data exploration, visualization, and analysis. The NCO also facilitates basic and applied research related to phenology, the development of decision-support tools for resource managers and planners, and the design of educational and outreach materials

Fact Sheet↗
USGS2005

The life cycle of a mineral deposit: a teacher's guide for hands-on mineral education activities

This teacher's guide defines what a mineral deposit is and how a mineral deposit is identified and measured, how the mineral resources are extracted, and how the mining site is reclaimed; how minerals and mineral resources are processed; and how we use mineral resources in our every day lives. Included are 10 activitybased learning exercises that educate students on basic geologic concepts; the processes of finding, identifying, and extracting the resources from a mineral deposit; and the uses of minerals. The guide is intended for K through 12 Earth science teachers and students and is designed to meet the National Science Content Standards as defined by the National Research Council (1996). To assist in the understanding of some of the geology and mineral terms, see the Glossary (appendix 1) and Minerals and Their Uses (appendix 2). The process of finding or exploring for a mineral deposit, extracting or mining the resource, recovering the resource, also known as beneficiation, and reclaiming the land mined can be described as the “life cycle” of a mineral deposit. The complete process is time consuming and expensive, requiring the use of modern technology and equipment, and may take many years to complete. Sometimes one entity or company completes the entire process from discovery to reclamation, but often it requires multiple groups with specialized experience working together. Mineral deposits are the source of many important commodities, such as copper and gold, used by our society, but it is important to realize that mineral deposits are a nonrenewable resource. Once mined, they are exhausted, and another source must be found. New mineral deposits are being continuously created by the Earth but may take millions of years to form. Mineral deposits differ from renewable resources, such as agricultural and timber products, which may be replenished within a few months to several years.

General Information Product↗
USGS2013

Landscape factors and hydrology influence mercury concentrations in wading birds breeding in the Florida Everglades, USA

The hydrology of wetland ecosystems is a key driver of both mercury (Hg) methylation and waterbird foraging ecology, and hence may play a fundamental role in waterbird exposure and risk to Hg contamination. However, few studies have investigated hydrological factors that influence waterbird Hg exposure. We examined how several landscape-level hydrological variables influenced Hg concentrations in great egret and white ibis adults and chicks in the Florida Everglades. The great egret is a visual “exploiter” species that tolerates lower prey densities and is less sensitive to hydrological conditions than is the white ibis, which is a tactile “searcher” species that pursues higher prey densities in shallow water. Mercury concentrations in adult great egrets were most influenced by the spatial region that they occupied in the Everglades (higher in the southern region); whereas the number of days a site was dry during the previous dry season was the most important factor influencing Hg concentrations in adult ibis (Hg concentrations increased with the number of days dry). In contrast, Hg concentrations in egret chicks were most influenced by calendar date (increasing with date), whereas Hg concentrations in ibis chicks were most influenced by chick age, region, and water recession rate (Hg concentrations decreased with age, were higher in the southern regions, and increased with positive water recession rates). Our results indicate that both recent (preceding two weeks) hydrological conditions, and those of the prior year, influence Hg concentrations in wading birds. Further, these results suggest that Hg exposure in wading birds is driven by complex relationships between wading bird behavior and life stage, landscape hydrologic patterns, and biogeochemical processes.

Florida↗
USGS2018

Juvenile coho salmon growth and health in streams across an urbanization gradient

Expanding human population and urbanization alters freshwater systems through structural changes to habitat, temperature effects from increased runoff and reduced canopy cover, altered flows, and increased toxicants. Current stream assessments stop short of measuring health or condition of species utilizing these freshwater habitats and fail to link specific stressors mechanistically to the health of organisms in the stream. Juvenile fish growth integrates both external and internal conditions providing a useful indicator of habitat quality and ecosystem health. Thus, there is a need to account for ecological and environmental influences on fish growth accurately. Bioenergetics models can simulate changes in growth and consumption in response to environmental conditions and food availability to account for interactions between an organism's environmental experience and utilization of available resources. The bioenergetics approach accounts for how thermal regime, food supply, and food quality affect fish growth. This study used a bioenergetics modeling approach to evaluate the environmental factors influencing juvenile coho salmon growth among ten Pacific Northwest streams spanning an urban gradient. Urban streams tended to be warmer, have earlier emergence dates and stronger early season growth. However, fish in urban streams experienced increased stress through lower growth efficiencies, especially later in the summer as temperatures warmed, with as much as a 16.6% reduction when compared to fish from other streams. Bioenergetics modeling successfully characterized salmonid growth in small perennial streams as part of a more extensive monitoring program and provides a powerful assessment tool for characterizing mixed life-stage specific responses in urban streams.

Science of the Total Environment↗
USGS2024

Evidence of long-range transport of selenium downstream of coal mining operations in the Elk River Valley, Canada

Expanding coal-mining operations in the Elk River Valley (British Columbia, Canada) have increased total selenium (Se) concentrations in the transboundary Lake Koocanusa (Canada and United States), but the spatial extent of Se transport from the Elk River Mines is unknown. We evaluated multiple lines of evidence of long-range transport of Se at five sites downstream of the mines relative to a site unaffected by the mines. First, all mine-affected sites had increasing trends in flow-normalized Se concentrations between 2005 and 2021 (35–89%), while no trend was observed at the unaffected site between 2005 and 2017. Second, all mine-affected sites had elevated annual mean Se concentrations and 5-year mean annual loads (2013–2017) by up to an order of magnitude relative to the unaffected site. Third, Se concentrations and the magnitude of the concentration trend generally decreased with distance downstream from the mines while loads increased, which is consistent with the downstream transport of the bulk of the Se load from the mines with smaller contributions from other sources. These results provide multiple lines of evidence that Se from the Elk River Mines is transported over 575 river kilometers and may pose risks to aquatic life in the transboundary Columbia River.

Elk River Valley↗
USGS2019

The NASA Roadmap to Ocean Worlds

In this article, we summarize the work of the NASA Outer Planets Assessment Group (OPAG) Roadmaps to Ocean Worlds (ROW) group. The aim of this group is to assemble the scientific framework that will guide the exploration of ocean worlds, and to identify and prioritize science objectives for ocean worlds over the next several decades. The overarching goal of an Ocean Worlds exploration program as defined by ROW is to “identify ocean worlds, characterize their oceans, evaluate their habitability, search for life, and ultimately understand any life we find.” The ROW team supports the creation of an exploration program that studies the full spectrum of ocean worlds, that is, not just the exploration of known ocean worlds such as Europa but candidate ocean worlds such as Triton as well. The ROW team finds that the confirmed ocean worlds Enceladus, Titan, and Europa are the highest priority bodies to target in the near term to address ROW goals. Triton is the highest priority candidate ocean world to target in the near term. A major finding of this study is that, to map out a coherent Ocean Worlds Program, significant input is required from studies here on Earth; rigorous Research and Analysis studies are called for to enable some future ocean worlds missions to be thoughtfully planned and undertaken. A second finding is that progress needs to be made in the area of collaborations between Earth ocean scientists and extraterrestrial ocean scientists.

Astrobiology↗
USGS2019

Daily estimates reveal fine-scale temporal and spatial variation in fish survival across a stream network

Environmental drivers of population vital rates, such as temperature and precipitation, often vary at short time scales, and these fluctuations can have important impacts on population dynamics. However, relationships between survival and environmental conditions are typically modeled at coarse temporal scales, ignoring the role of daily environmental variation in survival. Our goal was to determine the importance of fine-scale temporal variation in survival to population dynamics of stream salmonids. We extended the Cormack–Jolly–Seber model to estimate daily survival rates from seasonal samples of individually marked brook trout ( Salvelinus fontinalis ) in a stream network. Daily variation in temperature and flow were strongly associated with survival, but relationships varied between juvenile and adult trout and among streams. In all streams, juveniles had higher mortality in warm, low-flow conditions, but in the two larger streams, cold, high-flow conditions also reduced juvenile survival. Adult survival decreased during low flows, particularly in the fall spawning period. Differing survival responses among stream network components to short-term environmental events created shifts in optimal location for maximum survival across life stages, seasons, and years.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2024

Broad scale community-level larval fish survey of southern Lake Erie

The early-life history stages of fish are sensitive to environmental change and therefore can indicate habitat quality as well as help predict recruitment of resident and transient fishes. In 2019, as part of the Lake Erie Cooperative Science and Monitoring Initiative, we conducted a lake-wide assessment of the ichthyoplankton community in U.S. nearshore waters and international offshore waters. The goal of this work was to characterize the larval fish community across the lake and assess species composition, phenology, and distribution of larvae. Ichthyoplankton were sampled weekly using bongo nets at ports beginning at the Detroit River and along the southern shore of Lake Erie to Dunkirk, NY, and less frequently in the Niagara River and offshore areas. Larval fish were present from March 26 through August 29, 2019. The first taxon to emerge was Lake Whitefish in all basins, followed by Walleye, Yellow Perch, and catostomids, depending on port. Mean total density peaked in mid-June due to high catches of Gizzard Shad, Morone spp., and Freshwater Drum in the western basin. Few fish were collected in the offshore sites. Taxa richness, diversity, and larval density were higher in the western basin and lower in the central and eastern basins, generally following the productivity gradient. This was the first study to provide a comprehensive community assessment of the ichthyoplankton community of Lake Erie and can provide a baseline to assess future change, especially in community composition or phenology, of larvae which are likely to respond to climate and habitat change.

Lake Erie↗
USGS2017

Metamorphosis affects metal concentrations and isotopic signatures in a mayfly ( Baetis tricaudatus ): Implications for the aquatic-terrestrial transfer of metals

Insect metamorphosis often results in substantial chemical changes that can alter contaminant concentrations and fractionate isotopes. We exposed larval mayflies ( Baetis tricaudatus ) and their food (periphyton) to an aqueous zinc gradient (3-340 µg Zn/l) and measured zinc concentrations at different stages of metamorphosis: larval, subimago, and imago. We also measured changes in stable isotopes (δ 15 N and δ 13 C) in unexposed mayflies. Larval zinc concentrations were positively related to aqueous zinc, increasing 9-fold across the exposure gradient. Adult zinc concentrations were also positively related to aqueous zinc, but were 7-fold lower than larvae. This relationship varied according to adult substage and sex. Tissue concentrations in female imagoes were not related to exposure concentrations, but the converse was true for all other stage-by-sex combinations. Metamorphosis also increased δ 15 N by ~0.8‰, but not δ 13 C. Thus, the main effects of metamorphosis on insect chemistry were large declines in zinc concentrations coupled with increased δ 15 N signatures. For zinc, this change was largely consistent across the aqueous exposure gradient. However, differences among sexes and stages suggest that caution is warranted when using nitrogen isotopes or metal concentrations measured in one insect stage (e.g. larvae) to assess risk to wildlife that feed on subsequent life stages (e.g. adults).

Environmental Science & Technology↗
USGS2013

U.S. Geological Survey environmental health science strategy — Providing environmental health science for a changing world

Executive Summary America has an abundance of natural resources. We have bountiful clean water, fertile soil, and unrivaled national parks, wildlife refuges, and public lands. These resources enrich our lives and preserve our health and wellbeing. These resources have been maintained because of our history of respect for their value and an enduring commitment to their vigilant protection. Awareness of the social, economic, and personal value of the health of our environment is increasing. The emergence of environmentally driven diseases caused by exposure to contaminants and pathogens is a growing concern worldwide. New health threats and patterns of established threats are affected by both natural and anthropogenic changes to the environment. Human activities are key drivers of emerging (new and re-emerging) health threats. Societal demands for land and natural resources, quality of life, and economic prosperity lead to environmental change. Natural earth processes, climate trends, and related climatic events will compound the environmental impact of human activities. These environmental drivers will influence exposure to disease agents, including viral, bacterial, prion, and fungal pathogens, parasites, synthetic chemicals and substances, natural earth materials, toxins, and other biogenic compounds. The U.S. Geological Survey (USGS) defines environmental health science broadly as the interdisciplinary study of relations among the quality of the physical environment, the health of the living environment, and human health. The interactions among these three spheres are driven by human activities, ecological processes, and natural earth processes; the interactions affect exposure to contaminants and pathogens and the severity of environmentally driven diseases in animals and people. This definition provides USGS with a framework for synthesizing natural science information from across the Bureau and providing it to environmental, natural resource, agricultural, and public health managers. USGS specializes in science at the environment-health interface, by characterizing the processes that affect the interaction among the physical environment, the living environment, and people, and the resulting factors that affect ecological and human exposure to disease agents. The USGS is a Federal science agency with a broad range of natural science expertise relevant to environmental health. USGS provides scientific information and tools as a scientific basis for management and policy decisionmaking. This report describes a 10-year strategy that encompasses the portfolio of USGS environmental health science. It summarizes national environmental health priorities that USGS is best suited to address, and will serve as a strategic framework for USGS environmental health science goals, actions, and outcomes for the next decade. Implementation of this strategy is intended to aid coordination of USGS environmental health activities and to provide a focal point for disseminating information to stakeholders. The “One Health” paradigm advocated by the World Health Organization (WHO; World Health Organization, 2011), and the American Veterinary Medical Association (AVMA; American Veterinary Medical Association, 2008), among others, is based on a general recognition that the health of humans, animals, and the environment are inextricably linked. Thus, successful efforts to protect that health will require increased interdisciplinary research and increased communication and collaboration among the broader scientific and health community. This strategy is built upon that paradigm.

Circular↗
USGS2020

Short-term forecasts of insect phenology inform pest management

Insect pests cost billions of dollars per year globally, negatively impacting food crops and infrastructure, and contributing to the spread of disease. Timely information regarding developmental stages of pests can facilitate early detection and control, increasing efficiency and effectiveness. In 2018, the U.S. National Phenology Network (USA-NPN) released a suite of ‘Pheno Forecast’ map products relevant to science and management. The Pheno Forecasts include real-time maps and short-term forecasts of insect pest activity at management-relevant spatial and temporal resolutions and are based on accumulated temperature thresholds associated with critical life-cycle stages of economically important pests. Pheno Forecasts indicate, for a specified day, the status of the insect’s target life-cycle stage in real time across the contiguous United States. The maps are available for 12 pest species including the invasive emerald ash borer ( Agrilus planipennis Fairmaire [Coleoptera: Buprestidae]), hemlock woolly adelgid ( Adelges tsugae Annand), and gypsy moth ( Lymantria dispar Linnaeus [Lepidoptera: Erebidae]). Preliminary validation based on in-situ observations for hemlock woolly adelgid egg and nymph stages in 2018 indicated the maps to be ≥93% accurate depending on phenophase. Since their release in early 2018, these maps have been adopted by tree care specialists and foresters across the United States. Using a consultative mode of engagement, USA-NPN staff have continuously sought input and critique of the maps and delivery from end users. Based on feedback received, maps have been expanded and modified to include additional species, improved descriptions of the phenophase event of interest, and e-mail-based notifications to support management decisions.

Annals of the Entomological Society of America↗
USGS2016

The logic of comparative life history studies for estimating key parameters, with a focus on natural mortality rate

There are a number of key parameters in population dynamics that are difficult to estimate, such as natural mortality rate, intrinsic rate of population growth, and stock-recruitment relationships. Often, these parameters of a stock are, or can be, estimated indirectly on the basis of comparative life history studies. That is, the relationship between a difficult to estimate parameter and life history correlates is examined over a wide variety of species in order to develop predictive equations. The form of these equations may be derived from life history theory or simply be suggested by exploratory data analysis. Similarly, population characteristics such as potential yield can be estimated by making use of a relationship between the population parameter and bio-chemico–physical characteristics of the ecosystem. Surprisingly, little work has been done to evaluate how well these indirect estimators work and, in fact, there is little guidance on how to conduct comparative life history studies and how to evaluate them. We consider five issues arising in such studies: (i) the parameters of interest may be ill-defined idealizations of the real world, (ii) true values of the parameters are not known for any species, (iii) selecting data based on the quality of the estimates can introduce a host of problems, (iv) the estimates that are available for comparison constitute a non-random sample of species from an ill-defined population of species of interest, and (v) the hierarchical nature of the data (e.g. stocks within species within genera within families, etc., with multiple observations at each level) warrants consideration. We discuss how these issues can be handled and how they shape the kinds of questions that can be asked of a database of life history studies.

ICES Journal of Marine Science↗
USGS2021

The roles of environmental variation and parasite survival in virulence–transmission relationships

Disease outbreaks are a consequence of interactions among the three components of a host–parasite system: the infectious agent, the host and the environment. While virulence and transmission are widely investigated, most studies of parasite life-history trade-offs are conducted with theoretical models or tractable experimental systems where transmission is standardized and the environment controlled. Yet, biotic and abiotic environmental factors can strongly affect disease dynamics, and ultimately, host–parasite coevolution. Here, we review research on how environmental context alters virulence–transmission relationships, focusing on the off-host portion of the parasite life cycle, and how variation in parasite survival affects the evolution of virulence and transmission. We review three inter-related ‘approaches’ that have dominated the study of the evolution of virulence and transmission for different host–parasite systems: (i) evolutionary trade-off theory, (ii) parasite local adaptation and (iii) parasite phylodynamics. These approaches consider the role of the environment in virulence and transmission evolution from different angles, which entail different advantages and potential biases. We suggest improvements to how to investigate virulence–transmission relationships, through conceptual and methodological developments and taking environmental context into consideration. By combining developments in life-history evolution, phylogenetics, adaptive dynamics and comparative genomics, we can improve our understanding of virulence–transmission relationships across a diversity of host–parasite systems that have eluded experimental study of parasite life history.

Royal Society Open Science↗
USGS2017

Characters in Arctostaphylos taxonomy

There is value in understanding the past and how it has affected the present. Science focuses on empirical findings, and we know that our prior experiences and those of our predecessors play important roles in determining how we interpret the present. We learn from accomplishments and foibles of predecessors and appreciate the real life experiences we have gone through. In our studies of the genus Arctostaphylos Adans. we have been struck by the fascinating stories surrounding taxonomists who have played roles in the development of our current understanding of the group. In addition to providing insights, they sometimes provide humor and lessons on the value of competition versus collaboration. We offer this history of the humans that forged the taxonomy behind Arctostaphylos classification in this light.

Madroño↗
USGS2021

A small proportion of breeders drive American bullfrog invasion of the Yellowstone River floodplain, Montana

The American bullfrog ( Lithobates catesbeianus ) is a non-native invader of aquatic habitats across the northwestern United States. It recently invaded the Yellowstone River, Montana, and has spread to over 140 km of floodplain habitat. We analyzed seven microsatellites in 528 tadpoles sampled across nearly the entire Yellowstone River invasion (about 140 river km) to characterize invasion genetics, compare our results with those of a recent mtDNA study ( Kamath et al. 2016 ), and to inform control efforts. Microsatellite variation supports the mtDNA-based hypothesis of at least two independent introductions to the floodplain from genetically divergent populations in the midwestern United States, followed by massive range expansion. One introduction is associated with the upstream extent of the invasion near Park City, Montana and the other more broadly with downstream populations. All sites were characterized by small effective numbers of breeders ( N b ; harmonic mean = 9.97), and therefore, a small proportion of highly successful adults may drive the invasion by producing large families. Microsatellites and mtDNA produced discordant estimates of genetic admixture between the upstream and downstream invasions, which may reflect small effective population size. Although we observed isolation by distance using both types of markers, microsatellites appear to reflect population structure resulting from secondary contact between the two introductions, as opposed to structure resulting from equilibrium between gene flow and genetic drift. Most sites showed evidence for genetic bottlenecks, which supports the recent history of invasion. Small N b paired with known high localized extinction rates following colonization suggests focused removal of post metamorphic life stages at sites less likely to go extinct on their own could help limit invasion by bullfrogs.

Montana↗