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At least 1,765 records · Page 98Linked to original sources

USGS2021

Demographic risk assessment for a harvested species threatened by climate change: Polar bears in the Chukchi Sea

Climate change threatens global biodiversity. Many species vulnerable to climate change are important to humans for nutritional, cultural, and economic reasons. Polar bears Ursus maritimus are threatened by sea-ice loss and represent a subsistence resource for Indigenous people. We applied a novel population modeling-management framework that is based on species life history and accounts for habitat loss to evaluate subsistence harvest for the Chukchi Sea (CS) polar bear subpopulation. Harvest strategies followed a state-dependent approach under which new data were used to update the harvest on a predetermined management interval. We found that a harvest strategy with a starting total harvest rate of 2.7% (˜85 bears/yr at current abundance), a 2:1 male-to-female ratio, and a 10-yr management interval would likely maintain subpopulation abundance above maximum net productivity level for the next 35 yr (approximately three polar bear generations), our primary criterion for sustainability. Plausible bounds on starting total harvest rate were 1.7–3.9%, where the range reflects uncertainty due to sampling variation, environmental variation, model selection, and differing levels of risk tolerance. The risk of undesired demographic outcomes (e.g., overharvest) was positively related to harvest rate, management interval, and projected declines in environmental carrying capacity; and negatively related to precision in population data. Results reflect several lines of evidence that the CS subpopulation has been productive in recent years, although it is uncertain how long this will last as sea-ice loss continues. Our methods provide a template for balancing trade-offs among protection, use, research investment, and other factors. Demographic risk assessment and state-dependent management will become increasingly important for harvested species, like polar bears, that exhibit spatiotemporal variation in their response to climate change.

Chukchi Sea↗

USGS2023

Review and development of best practices for toxicity tests with dreissenid mussels

Since their introduction to North America in the 1980s, research to develop effective control tools for invasive mussels ( Dreissena polymorpha and D. rostriformis bugensis ) has been ongoing across various research institutions using a range of testing methods. Inconsistencies in experimental methods and reporting present challenges for comparing data, repeating experiments, and applying results. The Invasive Mussel Collaborative established the Toxicity Testing Work Group (TTWG) in 2019 to identify “best practices” and guide development of a standard framework for dreissenid mussel toxicity testing protocols. We reviewed the literature related to laboratory-based dreissenid mussel toxicity tests and determined the degree to which standard guidelines have been used and their applicability to dreissenid mussel testing. We extracted detailed methodology from 99 studies from the peer-reviewed and gray literature and conducted a separate analysis for studies using presettlement and postsettlement mussels. We identified specific components of methods and approaches that could be refined or standardized for dreissenid mussels. These components included species identification, collection methods, size/age class distinction, maintenance practices, testing criteria, sample size, response measures, reporting parameters, exposure methods, and mortality criteria. We consulted experts in the field of aquatic toxicology and dreissenid mussel biology on our proposed. The final recommendations contained in the present review are based on published standard guidelines, methods reported in the published and gray literature, and the expertise of TTWG members and an external panel. In addition, our review identifies research needs for dreissenid mussel testing including improved methods for early–life stage testing, comparative data on life stages and between dreissenid mussel species, inclusion of a reference toxicant, and additional testing of nontarget species (i.e., other aquatic organisms). Environ Toxicol Chem 2023;42:1649–1666. © 2023 His Majesty the King in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Environmental Toxicology and Chemistry↗

USGS2017

Ecosystem features determine seagrass community response to sea otter foraging

Comparing sea otter recovery in California (CA) and British Columbia (BC) reveals key ecosystem properties that shape top-down effects in seagrass communities. We review potential ecosystem drivers of sea otter foraging in CA and BC seagrass beds, including the role of coastline complexity and environmental stress on sea otter effects. In BC, we find greater species richness across seagrass trophic assemblages. Furthermore, Cancer spp. crabs, an important link in the seagrass trophic cascade observed in CA, are less common. Additionally, the more recent reintroduction of sea otters, more complex coastline, and reduced environmental stress in BC seagrass habitats supports the hypotheses that sea otter foraging pressure is currently reduced there. In order to manage the ecosystem features that lead to regional differences in top predator effects in seagrass communities, we review our findings, their spatial and temporal constraints, and present a social-ecological framework for future research.

British Columbia, California↗

USGS2022

Ecological and socioeconomic factors associated with the human burden of environmentally mediated pathogens: A global analysis

Background Billions of people living in poverty are at risk of environmentally mediated infectious diseases—that is, pathogens with environmental reservoirs that affect disease persistence and control and where environmental control of pathogens can reduce human risk. The complex ecology of these diseases creates a global health problem not easily solved with medical treatment alone. Methods We quantified the current global disease burden caused by environmentally mediated infectious diseases and used a structural equation model to explore environmental and socioeconomic factors associated with the human burden of environmentally mediated pathogens across all countries. Findings We found that around 80% (455 of 560) of WHO-tracked pathogen species known to infect humans are environmentally mediated, causing about 40% (129 488 of 359 341 disability-adjusted life years) of contemporary infectious disease burden (global loss of 130 million years of healthy life annually). The majority of this environmentally mediated disease burden occurs in tropical countries, and the poorest countries carry the highest burdens across all latitudes. We found weak associations between disease burden and biodiversity or agricultural land use at the global scale. In contrast, the proportion of people with rural poor livelihoods in a country was a strong proximate indicator of environmentally mediated infectious disease burden. Political stability and wealth were associated with improved sanitation, better health care, and lower proportions of rural poverty, indirectly resulting in lower burdens of environmentally mediated infections. Rarely, environmentally mediated pathogens can evolve into global pandemics (eg, HIV, COVID-19) affecting even the wealthiest communities. Interpretation The high and uneven burden of environmentally mediated infections highlights the need for innovative social and ecological interventions to complement biomedical advances in the pursuit of global health and sustainability goals. Funding Bill & Melinda Gates Foundation, National Institutes of Health, National Science Foundation, Alfred P. Sloan Foundation, National Institute for Mathematical and Biological Synthesis, Stanford University, and the US Defense Advanced Research Projects Agency.

The Lancet Planetary Health↗

USGS2014

Successes and challenges from formation to implementation of eleven broad-extent conservation programs

Integration of conservation partnerships across geographic, biological, and administrative boundaries is increasingly relevant because drivers of change, such as climate shifts, transcend these boundaries. We explored successes and challenges of established conservation programs that span multiple watersheds and consider both social and ecological concerns. We asked representatives from a diverse set of 11 broadextent conservation partnerships in 29 countries 17 questions that pertained to launching and maintaining partnerships for broad-extent conservation, specifying ultimate management objectives, and implementation and learning. Partnerships invested more funds in implementing conservation actions than any other aspect of conservation, and a program’s context (geographic extent, United States vs. other countries, developed vs. developing nation) appeared to substantially affect program approach. Despite early successes of these organizations and benefits of broad-extent conservation, specific challenges related to uncertainties in scaling up information and to coordination in the face of diverse partner governance structures, conflicting objectives, and vast uncertainties regarding future system dynamics hindered long-term success, as demonstrated by the focal organizations. Engaging stakeholders, developing conservation measures, and implementing adaptive management were dominant challenges. To inform future research on broad-extent conservation, we considered several challenges when we developed detailed questions, such as what qualities of broad-extent partnerships ensure they complement, integrate, and strengthen, rather than replace, local conservation efforts and which adaptive management processes yield actionable conservation strategies that account explicitly for dynamics and uncertainties regarding multiscale governance, environmental conditions, and knowledge of the system?

Conservation Biology↗

USGS2025

Bridging theory and practice to inform seed selection for restoration

Introduction Land managers often face the critical decision of what plant materials to select for ecological restoration. Selection depends on factors that span ecological conditions and human interventions in the restoration process, which can strongly influence the recovery of a degraded ecosystem. Objectives To improve the seed selection process, we compared scientific literature and guidance from five federal agencies to bridge seed selection “theory” and “practice” in the interior western and central United States. Methods We extracted recurring themes and keywords associated with abiotic, biotic, land management, and producer practices that influence seed selection and analyzed their proportional use between agency guidance and scientific literature. Results We identified significant overlap between key concepts in guidance and literature, highlighting the interconnectedness between science and management. However, nuanced patterns emerged across seed selection themes, including more focus in the literature on local adaptation and genetic structure, ramifications of introducing gene flow and artificial selection during plant production, and provenancing strategies to address changing climatic conditions. In contrast, agency guidance focused on genetically appropriate and environmentally suitable seed selection and practical concerns, including seed cost, availability, and diversity. Seed selection studies in the literature were concentrated in the Great Basin and Colorado Plateau, scattered in the Great Plains, and were largely experimental. Conclusions Our review suggests new opportunities for co-production of science and decision-making frameworks among researchers, land managers, and seed producers to inform seed selection guidance for restoration.

Restoration Ecology↗

USGS2022

Geoenvironmental model for roll-type uranium deposits in the Texas Gulf Coast

Geoenvironmental models were formulated by the U.S. Geological Survey in the 1990s to describe potential environmental effects of extracting different types of ore deposits in different geologic and climatic regions. This paper presents a geoenvironmental model for roll-front (roll-type) uranium deposits in the Texas Coastal Plain. The model reviews descriptive and quantitative information derived from environmental studies and existing databases to depict existing conditions and potential environmental concerns associated with mining this deposit type. This geoenvironmental model describes how features of the deposits including host rock; ore and gangue mineralogy; geologic, hydrologic, and climatic settings; and mining methods (legacy open-pit and in situ recovery [ISR]) influence potential environmental effects from mining. Element concentrations in soil and water are compared to regulatory thresholds to depict ambient surface water and groundwater conditions. Although most open-pit operations in this region have been reclaimed, concerns remain about groundwater quality at three of the four former mills that supported former open-pit mines and are undergoing closure activities. The primary environmental concerns with ISR mining are (1) radon gas at active ISR operations, (2) radiation or contaminant leakage during production and transport of ISR resin or yellowcake, (3) uranium excursions into groundwater surrounding active ISR operations, and (4) contamination of groundwater after ISR mining. Although existing regulations attempt to address these concerns, some problems remain. Researchers suggest that reactive transport modeling and a better understanding of geology, stratigraphy, and geochemistry of ISR production areas could minimize excursions into surrounding aquifers and improve results of groundwater restoration.

Texas↗

USGS2001

Dispersal

The ability of species to migrate and disperse is a trait that has interested ecologists for many years. Now that so many species and ecosystems face major environmental threats from habitat fragmentation and global climate change, the ability of species to adapt to these changes by dispersing, migrating, or moving between patches of habitat can be crucial to ensuring their survival. This book provides a timely and wide-ranging overview of the study of dispersal and incorporates much of the latest research. The causes, mechanisms, and consequences of dispersal at the individual, population, species and community levels are considered. The potential of new techniques and models for studying dispersal, drawn from molecular biology and demography, is also explored. Perspectives and insights are offered from the fields of evolution, conservation biology and genetics. Throughout the book, theoretical approaches are combined with empirical data, and care has been taken to include examples from as wide a range of species as possible.

Book↗

USGS2024

Monarch butterfly (Danaus plexippus) roost site-selection criteria and locations east of the Appalachian Mountains, U.S.A.

The monarch butterfly is a flagship species and pollinator whose populations have declined by 85% in the recent two decades. Their largest population overwinters in Mexico, then disperses across eastern North America during March to August. During September-December, they return south using two flyways, one that spans the central United States and another that follows the Atlantic coast. Migrating monarchs fly diurnally and roost in groups nocturnally. We sought to determine the criteria this species uses to select roost sites, and the landscape context where those sites are found. We developed species distribution models of the landscape context of Atlantic flyway roost sites via citizen scientist observations and environmental variables that affect monarchs in the adult stage prior to migration, using two algorithms (Maximum Entropy and Genetic Algorithm for Ruleset Prediction). We developed two model validation methods: a citizen scientist smartphone application and peer-informed comparisons with aerial imagery. Proximity to surface water, elevation, and vegetative cover were the most important criteria for monarch roost site selection. Our model predicted 2.6 million ha (2.9% of the study area) of suitable roosting habitat in the Atlantic flyway, with the greatest availability along the Atlantic coastal plain and Appalachian Mountain ridges. Conservation of this species is difficult, as monarchs range over both large areas and various habitat types, and most current monarch research and conservation efforts are focused on the breeding and overwintering periods. These models can serve to help prioritize surveys of roosting sites and conservation efforts during the monarchs’ fall migration.

Journal of Insect Behavior↗

USGS2024

Estimating lithium concentrations in groundwater used as drinking water for the conterminous United States

Lithium (Li) concentrations in drinking-water supplies are not regulated in the United States; however, Li is included in the 2022 U.S. Environmental Protection Agency list of unregulated contaminants for monitoring by public water systems. Li is used pharmaceutically to treat bipolar disorder, and studies have linked its occurrence in drinking water to human-health outcomes. An extreme gradient boosting model was developed to estimate geogenic Li in drinking-water supply wells throughout the conterminous United States. The model was trained using Li measurements from ∼13,500 wells and predictor variables related to its natural occurrence in groundwater. The model predicts the probability of Li in four concentration classifications, ≤4 μg/L, >4 to ≤10 μg/L, >10 to ≤30 μg/L, and >30 μg/L. Model predictions were evaluated using wells held out from model training and with new data and have an accuracy of 47–65%. Important predictor variables include average annual precipitation, well depth, and soil geochemistry. Model predictions were mapped at a spatial resolution of 1 km 2 and represent well depths associated with public- and private-supply wells. This model was developed by hydrologists and public-health researchers to estimate Li exposure from drinking water and compare to national-scale human-health data for a better understanding of dose–response to low (<30 μg/L) concentrations of Li.

conterminous United States↗

USGS2015

Spatial and temporal variability in growth of southern flounder ( Paralichthys lethostigma )

Delineation of stock structure is important for understanding the ecology and management of many fish populations, particularly those with wide-ranging distributions and high levels of harvest. Southern flounder ( Paralichthys lethostigma ) is a popular commercial and recreational species along the southeast Atlantic coast and Gulf of Mexico, USA. Recent studies have provided genetic and otolith morphology evidence that the Gulf of Mexico and Atlantic Ocean stocks differ. Using age and growth data from four states (Texas, Alabama, South Carolina, and North Carolina) we expanded upon the traditional von Bertalanffy model in order to compare growth rates of putative geographic stocks of southern flounder. We improved the model fitting process by adding a hierarchical Bayesian framework to allow each parameter to vary spatially or temporally as a random effect, as well as log transforming the three model parameters ( L ∞ , K , and t 0 ). Multiple comparisons of parameters showed that growth rates varied (even within states) for females, but less for males. Growth rates were also consistent through time, when long-term data were available. Since within-basin populations are thought to be genetically well-mixed, our results suggest that consistent small-scale environmental conditions (i.e., within estuaries) likely drive growth rates and should be considered when developing broader scale management plans.

Fisheries Research↗

USGS2020

Imprint of regional oceanography on foraminifera of eastern Pacific Coral Reefs

The marginal marine environments of the eastern tropical Pacific (ETP) serve as an ideal natural laboratory to study how oceanographic and climatic variability influence coral-reef ecosystems. Reefs along the Pacific coast of Panamá span a natural gradient of nutrients, pH, and temperature as a result of stronger seasonal upwelling in the Gulf of Panamá relative to the Gulf of Chiriquí. The ecosystems are not only influenced by spatial and seasonal variations in oceanography but are affected by the climatic variability of the El Niño-Southern Oscillation (ENSO). Foraminifera can be robust indicators of ecosystem condition because the composition of their assemblages and the geochemistry of their tests can change rapidly in response to environmental variability. We studied benthic foraminifera in sediment samples collected from 3 m below mean sea level in the Gulf of Panamá and the Gulf of Chiriquí. Temperature loggers deployed from 2016 to 2019 showed that average temperatures were lower and more variable in the Gulf of Panamá due to seasonal upwelling. All sites in both gulfs were dominated by heterotrophic foraminifera, which was likely the result of nutrient enrichment due to upwelling, combined with ENSO effects. However, the Gulf of Chiriquí was characterized by higher abundances of symbiont-bearing foraminifera than the Gulf of Panamá. The orders Miliolida and Rotaliida dominated the foraminiferal assemblages in both gulfs, with Quinqueloculina and Rosalina being the most abundant genera in the two orders, respectively. Miliolids were less abundant in the Gulf of Panamá than in the Gulf of Chiriquí, whereas rotaliid densities were not significantly different between the two gulfs. Lower pH in the Gulf of Panamá as a result of upwelling may have contributed to the lower abundance of miliolids, which secrete tests of high-magnesium calcite. Geochemical analysis of tests of the symbiont-bearing miliolid Sorites marginalis revealed that foraminiferal Mg/Ca ratios were lower in the Gulf of Panamá than in the Gulf of Chiriquí. The offset in foraminiferal Mg/Ca is consistent with the lower mean annual temperature observed in the Gulf of Panamá due to stronger seasonal upwelling. Because the geochemistry and assemblages of foraminifera reflect differences in environmental conditions, they could potentially be used in tandem with coral proxies to reconstruct past environmental change and project the future of coral-reef systems within the ETP.

Gulf of Chiriqui, Gulf of Panama↗

USGS2016

A science of integration: frameworks, processes, and products in a place-based, integrative study

Integrative research is increasingly a priority within the scientific community and is a central goal for the evolving field of sustainability science. While it is conceptually attractive, its successful implementation has been challenging and recent work suggests that the move towards interdisciplinarity and transdisciplinarity in sustainability science is being only partially realized. To address this from the perspective of social-ecological systems (SES) research, we examine the process of conducting a science of integration within the Southcentral Alaska Test Case (SCTC) of Alaska-EPSCoR as a test-bed for this approach. The SCTC is part of a large, 5 year, interdisciplinary study investigating changing environments and adaptations to those changes in Alaska. In this paper, we review progress toward a science of integration and present our efforts to confront the practical issues of applying proposed integration frameworks. We: (1) define our integration framework; (2) describe the collaborative processes, including the co-development of science through stakeholder engagement and partnerships; and (3) illustrate potential products of integrative, social-ecological systems research. The approaches we use can also be applied outside of this particular framework. We highlight challenges and propose improvements for integration in sustainability science by addressing the need for common frameworks and improved contextual understanding. These insights may be useful for capacity-building for interdisciplinary projects that address complex real-world social and environmental problems.

Sustainability Science↗

USGS2018

Toward a resilience-based conservation strategy for wetlands in Puerto Rico: Meeting challenges posed by environmental change

Designing conservation strategies in human-dominated landscapes is challenging, owing to complex human-natural systems and evolving societal values. To meet this challenge, a robust, adaptive strategy should have a process for flexible implementation of incremental actions. We describe a hypothetical example for the Rio Grande de Arecibo watershed and coastal wetlands in Puerto Rico to address the first component. The process begins by identifying shared stakeholder objectives. This process benefits from a review of foundational research and knowledge base that includes global forcings and vulnerability of resources of interest. Forcings include climate change and pervasive urban sprawl. We focus on two taxonomic groups with differing life histories but strong dependence on water resource dynamics, another resource valued by humans. We stipulate objectives and multiple actions, but focus on those pertaining to hydro-management as the common thread in our example. We advanced two decision contexts of contrasting complexity, illustrated links between objectives and actions, and highlighted trade-offs triggered by varying resource valuation. Our focus was to highlight various components necessary to frame a resilience-based strategy, but we cannot overemphasize the importance of accommodating institutional and stakeholder changing priorities and values to ensure its successful implementation.

Puerto Rico↗

USGS2008

Environmental drivers in mangrove establishment and early development: A review

Mangroves have a global distribution within coastal tropical and subtropical climates, and have even expanded to some temperate locales. Where they do occur, mangroves provide a plethora of goods and services, ranging from coastal protection from storms and erosion to direct income for human societies. The mangrove literature has become rather voluminous, prompting many subdisciplines within a field that earlier in the 20th century received little focus. Much of this research has become diffuse by sheer numbers, requiring detailed syntheses to make research results widely available to resource managers. In this review, we take an inclusive approach in focusing on eco-physiological and growth constraints to the establishment and early development of mangrove seedlings in the intertidal zone. This is a critical life stage for mangroves, i.e., the period between dispersal and recruitment to the sapling stage. We begin with some of the research that has set the precedent for seedling-level eco-physiological research in mangroves, and then we focus on recent advances (circa. 1995 to present) in our understanding of temperature, carbon dioxide, salinity, light, nutrient, flooding, and specific biotic influences on seedling survival and growth. As such, we take a new approach in describing seedling response to global factors (e.g., temperature) along with site-specific factors (e.g., salinity). All variables will strongly influence the future of seedling dynamics in ways perhaps not yet documented in mature forests. Furthermore, understanding how different mangrove species can respond to global factors and regional influences is useful for diagnosing observed mortality within mangrove wetlands, managed or natural. This review provides an updated eco-physiological knowledge base for future research and reforestation activity, and for understanding important links among climate change, local physico-chemical condition, and establishment and early growth of mangrove seedlings.

Aquatic Botany↗

USGS2014

Correlation of gene expression and contaminat concentrations in wild largescale suckers: a field-based study

Toxic compounds such as organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ether flame retardants (PBDEs) have been detected in fish, birds, and aquatic mammals that live in the Columbia River or use food resources from within the river. We developed a custom microarray for largescale suckers (Catostomus macrocheilus) and used it to investigate the molecular effects of contaminant exposure on wild fish in the Columbia River. Using Significance Analysis of Microarrays (SAM) we identified 72 probes representing 69 unique genes with expression patterns that correlated with hepatic tissue levels of OCs, PCBs, or PBDEs. These genes were involved in many biological processes previously shown to respond to contaminant exposure, including drug and lipid metabolism, apoptosis, cellular transport, oxidative stress, and cellular chaperone function. The relation between gene expression and contaminant concentration suggests that these genes may respond to environmental contaminant exposure and are promising candidates for further field and laboratory studies to develop biomarkers for monitoring exposure of wild fish to contaminant mixtures found in the Columbia River Basin. The array developed in this study could also be a useful tool for studies involving endangered sucker species and other sucker species used in contaminant research.

Oregon;Washington↗

USGS2006

Environmental controls on denitrifying communities and denitrification rates: Insights from molecular methods

The advent of molecular techniques has improved our understanding of the microbial communities responsible for denitrification and is beginning to address their role in controlling denitrification processes. There is a large diversity of bacteria, archaea, and fungi capable of denitrification, and their community composition is structured by long-term environmental drivers. The range of temperature and moisture conditions, substrate availability, competition, and disturbances have long-lasting legacies on denitrifier community structure. These communities may differ in physiology, environmental tolerances to pH and O 2 , growth rate, and enzyme kinetics. Although factors such as O 2 , pH, C availability, and NO 3 − pools affect instantaneous rates, these drivers act through the biotic community. This review summarizes the results of molecular investigations of denitrifier communities in natural environments and provides a framework for developing future research for addressing connections between denitrifier community structure and function.

Ecological Applications↗

USGS2014

Strategic needs of water on the Yukon: An interdisciplinary approach to studying hydrology and climate change in the Lower Yukon River Basin

Strategic Needs of Water on the Yukon (SNOWY) is an interdisciplinary research project funded by the National Science Foundation (NSF; http://www.nsf.gov/ ). The SNOWY team is made up of a diverse group of researchers from different backgrounds and organizations. This partnership between scientists from different disciplines (hydrology, geography, and social science), government agencies, nonprofit organizations, universities, and Lower Yukon River Basin (LYRB) and Yukon-Kuskokwim (YK) Delta communities provided an opportunity to study the effects of climate change using a holistic approach. The Arctic and Subarctic are experiencing environmental change at a rate faster than the rest of the world, and the lack of historical baseline data in these often remote locations makes understanding and predicting regional climate change difficult. This project focused on collecting data to fill in these gaps by using both quantitative and qualitative methodologies to tell the story of environmental change in this region as told by the physical data and the people who rely on this landscape.

Alaska↗