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At least 649 records · Page 36Linked to original sources
USGS2014

A new analysis of Mars "Special Regions": findings of the Second MEPAG Special Regions Science Analysis Group (SR-SAG2)

A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and updated the description of Special Regions on Mars as places where terrestrial organisms might replicate (per the COSPAR Planetary Protection Policy). This review and update was conducted by an international team (SR-SAG2) drawn from both the biological science and Mars exploration communities, focused on understanding when and where Special Regions could occur. The study applied recently available data about martian environments and about terrestrial organisms, building on a previous analysis of Mars Special Regions (2006) undertaken by a similar team. Since then, a new body of highly relevant information has been generated from the Mars Reconnaissance Orbiter (launched in 2005) and Phoenix (2007) and data from Mars Express and the twin Mars Exploration Rovers (all 2003). Results have also been gleaned from the Mars Science Laboratory (launched in 2011). In addition to Mars data, there is a considerable body of new data regarding the known environmental limits to life on Earth—including the potential for terrestrial microbial life to survive and replicate under martian environmental conditions. The SR-SAG2 analysis has included an examination of new Mars models relevant to natural environmental variation in water activity and temperature; a review and reconsideration of the current parameters used to define Special Regions; and updated maps and descriptions of the martian environments recommended for treatment as "Uncertain" or "Special" as natural features or those potentially formed by the influence of future landed spacecraft. Significant changes in our knowledge of the capabilities of terrestrial organisms and the existence of possibly habitable martian environments have led to a new appreciation of where Mars Special Regions may be identified and protected. The SR-SAG also considered the impact of Special Regions on potential future human missions to Mars, both as locations of potential resources and as places that should not be inadvertently contaminated by human activity.

Astrobiology↗
USGS2026

Harmonization of aggregated freshwater biotic data to support continental and global assessment

Biodiversity loss and conservation are increasingly coming into focus in global policy fora, requiring information and assessments at wider spatial and temporal scales than previously considered. However, the monitoring framework required to support such data collection and assessment is lacking in many countries and is not harmonized across countries, hampering these efforts. Aggregation of existing freshwater data offers a solution to the problem of assessing status and trends of ecosystems and biodiversity at large spatial scales in the absence of nationally coordinated monitoring efforts. Analysis of aggregated data from different sources, collected using different protocols and with varying levels of metadata and supporting data, can be challenging and requires decisions regarding data comparability. In this paper, we identify the challenges inherent in harmonizing aggregated freshwater data for analysis, including general concerns related to research goals, spatial and temporal scale, sample selection, sampling effort, and site integrity. We also discuss the challenges related to measured parameters, sampled habitats, sample collection and processing methods, and data integrity for phytoplankton, benthic algae, macrophytes, zooplankton, benthic macroinvertebrates, fish, and supporting variables such as water and sediment chemistry. We provide a workflow to evaluate each of these challenges and make decisions about how best to work with the data. Finally, we review a case study from a large-scale analysis of freshwater data from the circumpolar Arctic region that exemplifies the encountered challenges and the chosen solutions. Through the description of the case study, we provide practical solutions to support aggregation and analysis of existing freshwater data. As global conversations about biodiversity status and trends continue, the demand for large-scale analyses of data from different sources will only grow. In the absence of globally harmonized monitoring, we are faced with the need to ensure comparability of data, making expert judgements where needed to support sound conclusions.

PLOS Water↗
USGS2001

Acidic deposition in the northeastern United States: Sources and inputs, ecosystem effects, and management strategies: The effects of acidic deposition in the northeastern United States include the acidification of soil and water, which stresses terrestrial and aquatic biota

Acidic deposition is the transfer of strong acids and acid-forming substances from the atmosphere to the surface of the Earth. The composition of acidic deposition includes ions, gases, and particles derived from the following: gaseous emissions of sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), ammonia (NH 3 ), and particulate emissions of acidifying and neutralizing compounds. Over the past quarter century of study, acidic deposition has emerged as a critical environmental stress that affects forested landscapes and aquatic ecosystems in North America, Europe, and Asia. This complex problem is an example of a new class of environmental issues that are multiregional in scale and are not amenable to simple resolution by policymakers. Acidic deposition can originate from transboundary air pollution and can affect large geographic areas. It is highly variable across space and time, links air pollution to diverse terrestrial and aquatic ecosystems, and alters the interactions of many elements (e.g., sulfur [S], nitrogen [N], hydrogen ion [H + ], calcium [Ca 2+ ], magnesium [Mg 2+ ], and aluminum [Al]). It also contributes directly and indirectly to biological stress and to the degradation of ecosystems. Despite the complexity of the effects of acidic deposition, North American and European management actions directed toward the recovery of damaged natural resources have resulted in recent decreases in both emissions and deposition of acidic S compounds. Accordingly, acidic deposition presents an instructive case study for coordinating science and policy efforts aimed at resolving large-scale environmental problems.

northeastern United States↗
USGS2024

The National Ocean Biodiversity Strategy

President Biden has been clear that the ocean is central to life on Earth. As he has proclaimed, “the ocean powers millions of jobs; feeds and sustains us; and is a rejuvenating source of inspiration, exploration, and recreation.” The Biden-Harris Administration has worked hard to fulfill the President’s goal to protect and conserve at least 30% of U.S. waters by 2030. The ocean faces increased threats from warming, overfishing, increased acidity, and loss of biodiversity. It is now more important than ever to sustain the many benefits that the ocean, coasts, and Great Lakes provide, including food, a favorable climate, recreation, physical and mental health, and for many, a sense of cultural identity. Ocean life represents an irreplaceable heritage, the foundation of a habitable planet, and a vast trove of resources. Keeping our ocean healthy requires reliable information on the changing status of these living organisms, the drivers of biodiversity change, and options for effectively addressing those drivers. Over 2 million species are estimated to live in the ocean, yet only about 240,000 species have been described by scientists. Most of the ocean’s benefits result from those diverse species interacting with one another and the environment they create. To protect and conserve the ocean, we as a nation need to make better use of existing knowledge and prioritize acquiring new biodiversity knowledge to enable better policy and management decisions. The ability to monitor ocean species and habitats has expanded dramatically over the past decade, with innovations in technology, genomics, taxonomy, big data management and sharing, artificial intelligence, and machine learning. Yet large fractions of the U.S. ocean remain almost unknown. The National Ocean Biodiversity Strategy (strategy) reflects the urgent need to leverage these advances. The goals of this strategy must be guided by the nation’s diverse voices and ways of knowing, in order to maximize effective and equitable stewardship of the ocean’s diverse life and its benefits to people. The strategy is intended as a guiding document for government to advance three overarching goals: ● Goal 1: Drive delivery of ocean biodiversity knowledge at the national scale. Objectives include developing an Implementation Plan for achieving the strategy’s three goals; establishing a coordination mechanism to manage the implementation; and documenting gaps in biodiversity knowledge and the benefits of ocean biodiversity to people and economies. ● Goal 2: Strengthen tools and institutions to deliver ocean biodiversity knowledge. Objectives include establishing a robust information pipeline to support indicators and dynamic maps of ocean biodiversity, from the coasts to the deep sea. This pipeline should include expanded observing systems and comprehensive data management; science and technology solutions to accelerate the availability of biodiversity information; and plans to leverage previous investments to rebuild and expand the nation’s human capital and infrastructure to sustain foundational taxonomy and biodiversity science. ● Goal 3: Protect, conserve, restore, and sustainably use ocean biodiversity. Objectives include expanding the collection, delivery, and use of biodiversity knowledge to inform actions that advance ocean protection, conservation, restoration, and sustainable development. Government should lead in establishing and incentivizing diverse partnerships across scales and sectors to implement those actions and should educate and involve the public to discover and value the nation’s diverse ocean life. Achieving these goals will require commitments across society: new federal and private investments, coordination across sectors to address climate and equity challenges, and engagement of Indigenous Knowledge holders and frontline communities as full partners throughout planning and implementation. The Subcommittee on Ocean Science and Technology (SOST) IWG-Biodiversity will begin developing an Implementation Plan to describe and direct specific actions to implement the strategy. Successful implementation of the strategy will harmonize and expand collection and delivery of timely knowledge on ocean life to all of society. The strategy will also enable evidence-based management and protection of the ocean. Advancing the strategy will build human and institutional capital and partnerships that support both existing mandates and new needs to rebuild and sustain biodiversity, achieve healthy ocean ecosystems, and manage living resources. Implementing the strategy will deliver knowledge for monitoring, modeling, forecasting, and assessments that support food security, public health, and cultural values, and that more effectively protect, conserve, and restore nature.

Report↗
USGS2012

Changing climate, changing forests: the impacts of climate change on forests of the northeastern United States and eastern Canada

Decades of study on climatic change and its direct and indirect effects on forest ecosystems provide important insights for forest science, management, and policy. A synthesis of recent research from the northeastern United States and eastern Canada shows that the climate of the region has become warmer and wetter over the past 100 years and that there are more extreme precipitation events. Greater change is projected in the future. The amount of projected future change depends on the emissions scenarios used. Tree species composition of northeast forests has shifted slowly in response to climate for thousands of years. However, current human-accelerated climate change is much more rapid and it is unclear how forests will respond to large changes in suitable habitat. Projections indicate significant declines in suitable habitat for spruce-fir forests and expansion of suitable habitat for oak-dominated forests. Productivity gains that might result from extended growing seasons and carbon dioxide and nitrogen fertilization may be offset by productivity losses associated with the disruption of species assemblages and concurrent stresses associated with potential increases in atmospheric deposition of pollutants, forest fragmentation, and nuisance species. Investigations of links to water and nutrient cycling suggest that changes in evapotranspiration, soil respiration, and mineralization rates could result in significant alterations of key ecosystem processes. Climate change affects the distribution and abundance of many wildlife species in the region through changes in habitat, food availability, thermal tolerances, species interactions such as competition, and susceptibility to parasites and disease. Birds are the most studied northeastern taxa. Twenty-seven of the 38 bird species for which we have adequate long-term records have expanded their ranges predominantly in a northward direction. There is some evidence to suggest that novel species, including pests and pathogens, may be more adept at adjusting to changing climatic conditions, enhancing their competitive ability relative to native species. With the accumulating evidence of climate change and its potential effects, forest stewardship efforts would benefit from integrating climate mitigation and adaptation options in conservation and management plans.

Connecticut;Labrador;Maine;Massachusetts;New Bruns↗
USGS2019

Managing effects of drought and other water resource challenges in Alaska and the Pacific Northwest

This is a Cooperator Report. As such, there is no specific abstract. The physical, ecological, and social environments of Alaska and the Pacific Northwest (PNW) region of the United States are extremely diverse. Alaska ranges from the Arctic Ocean and the very cold, dry environments of the North Slope to the cool and very rainy coastal North Pacific region of Southeast Alaska. Most precipitation falls as snow at higher elevations. In Arctic Alaska, average annual temperature is 14.6 F, and average annual precipitation is 11 inches. By contrast, in Southeast Alaska, average annual temperature is 35.8 F, and annual average precipitation is 143 inches. The PNW, defined here as Idaho, Oregon, and Washington, ranges from the Pacific Coast (annual precipitation of 200 inches) to interior semi-arid regions (annual precipitation of 8 inches). Precipitation patterns in the PNW are strongly governed by orographic phenomena, with high, persistent snowpack in the higher mountains (e.g., record annual snowfall of 1,130 in at Mount Baker, Washington in 1999-2000). Ecosystems in the PNW include productive temperate coniferous forests near the Pacific coast and along the (wet) west slope of the Cascade Range, less productive mixed-conifer forest along the (dry) east slope of the Cascades and in interior mountain ranges, and sagebrush-steppe and shrublands at lower elevations in much of the interior and mountain valleys. Large rivers and thousands of smaller tributaries form an extensive network of riparian, wetland, and estuarine systems that provide both critical hydrologic function and biological diversity at broad and fine spatial scales. Although Alaska and the Pacific Northwest differ in important physical, ecological, and social features, the importance of natural resources is evident in both regions. Water is important for wildlife and people. Water provides critical habitat for salmon, which are culturally and economically valuable species. Timber production has declined in recent decades. Recreation has emerged as a major revenue source.

Alaska, Oregon, Washington↗
USGS2014

Temporal variation in development of ecosystem services from oyster reef restoration

Restoration ecology relies heavily on ecosystem development theories that generally assume development of fully functioning natural systems over time, but often fail to identify the time-frame required for provision of desired functions, or acknowledge different pathways of functional development. In estuaries, a decline of overall habitat quality and functioning has led to significant efforts to restore critical ecosystem services, recently through the creation and restoration of oyster reefs. Oyster reef restoration generally occurs with goals of (1) increasing water quality via filtration through sustainable oyster recruitment, (2) stabilizing shorelines, and (3) creating and enhancing critical estuarine habitat for fish and invertebrates. We restored over 260 m 2 of oyster reef habitat in coastal Louisiana and followed the development and provision of these ecosystem services from 2009 through 2012. Oysters recruited to reefs immediately, with densities of oysters greater than 75 mm exceeding 80 ind m −2 after 3 years, and provision of filtration rates of 1002 ± 187 L h −1 m −2 ; shoreline stabilization effects of the created reefs were minimal over the three years of monitoring, with some evidence of positive shoreline stabilization during higher wind/energy events only; increased nekton abundance of resident, but not larger transient fish was immediately measurable at the reefs, however, this failed to increase through time. Our results provide critical insights into the development trajectories of ecosystem services provided by restored oyster reefs, as well as the mechanisms mediating these changes. This is critical both ecologically to understand how and where a reef thrives, and for policy and management to guide decision-making related to oyster reef restoration and the crediting and accounting of ecosystem services.

Louisiana↗
USGS2015

A conceptual framework and monitoring strategy for movement of saltwater in the coastal plain aquifer system of Virginia

A conceptual framework synthesizes previous studies to provide an understanding of conditions, processes, and relations of saltwater to groundwater withdrawal in the Virginia Coastal Plain aquifer system. A strategy for monitoring saltwater movement is based on spatial relations between the saltwater-transition zone and 612 groundwater-production wells that were regulated during 2013 by the Virginia Department of Environmental Quality. The vertical position and lateral distance and direction of the bottom of each production well’s screened interval was calculated relative to previously published groundwater chloride iso-concentration surfaces. Spatial analysis identified 81 production wells completed in the Yorktown-Eastover and Potomac aquifers that are positioned in closest proximity to the 250-milligrams-per-liter chloride surface, and from which chloride concentrations are most likely to increase above the U.S. Environmental Protection Agency’s 250-milligrams-per-liter secondary maximum-contaminant level. Observation wells are specified to distinguish vertical upconing from lateral intrusion among individual production wells. To monitor upconing, an observation well is to be collocated with each production well and completed at about the altitude of the 250-milligrams-per-liter chloride iso-concentration surface. To monitor lateral intrusion, a potential location of an observation well is projected from the bottom of each production well’s screened interval, in the lateral direction to the underlying chloride surface to a distance of 1 mile. Monitoring potential withdrawal-induced movement of saltwater in the Virginia Coastal Plain aquifer system is needed to detect increases in chloride concentration before groundwater-production wells become contaminated. An investigation was undertaken during 2014 by the U.S. Geological Survey in cooperation with the Virginia Department of Environmental Quality, to provide a sound scientific understanding of saltwater movement and guidance to implement a monitoring program. Previous studies have theorized that the saltwater originated primarily from seawater repeatedly emplaced within aquifer sediments during the past about 65 million years. Subsequent flushing by fresh groundwater has been impeded across sediments filling the Chesapeake Bay impact crater. The resulting saltwater-transition zone has been mapped to exhibit a warped and steeply mounded dome shape about centered on the impact crater, and flanked by a nearly level and shallow plateau shape to the southeast. Groundwater chloride concentrations have historically fluctuated during periods of weeks to months, probably as a result of localized vertical upconing beneath individual production wells. Lateral intrusion takes several decades or more to horizontally displace groundwater across distances of about 1 mile toward production wells. Upconing is relatively immediate, but reversible, whereas lateral intrusion under the regionally landward hydraulic gradient may slowly, but permanently reposition the saltwater-transition zone. Upconing coupled with lateral intrusion is theorized to produce composite chloride-concentration trends that vary widely over time in response to changing water demands, and evolve dynamically from hydraulic interactions among multiple neighboring production wells. Some aspects of observation-well construction and sampling are of particular importance to monitoring saltwater movement in the Virginia Coastal Plain aquifer system. Observation wells should feature screened intervals generally of no more than 10 feet that isolate distinct parts of the aquifer, and be thoroughly developed for removal of drilling fluid and introduced water. Presample purging should fully displace stratified saltwater in the well casing upward to the pump. Stable flow should be maintained as field parameters are measured and sample containers are filled with filtered water isolated from the atmosphere and unaffected by surface temperature. Groundwater samples from both upconing and lateral-intrusion observation wells should initially be collected four times per year when wells are newly established, but can be more optimally timed with withdrawal once responses in chloride concentrations can be reliably predicted. Concentrations of major ions (1) determine the dominant chemical composition of groundwater at each well, (2) establish the relative position of the well within the saltwater-transition zone, and (3) provide data quality control by calculation of sample charge balance. For these reasons, samples initially collected for the first year from newly established observation wells should be analyzed for calcium, magnesium, sodium, and potassium cations and chloride, bicarbonate, carbonate, sulfate, fluoride, and bromide anions. Inflection-point titration for alkalinity should be completed in the field. Analysis of chloride and field parameters may be adequate on a long-term basis once the dominant chemical composition at each well is established. Specific conductance may also provide a surrogate for chloride concentration depending on regulatory policy. The saltwater-movement monitoring strategy is limited and constrained. Relative monitoring needs among groundwater-production wells, and construction of observation wells, depend on the accuracy of previously mapped groundwater chloride iso-concentration surfaces. Production wells in similar proximity to saltwater can differ in aquifer hydraulic conductivity, rates of withdrawal, and screened-interval lengths. Only production wells making withdrawals reported to the Virginia Department of Environmental Quality have been accounted for; undocumented production wells can result in spurious changes in groundwater chloride concentration. Upconing observation wells should be as close as possible to corresponding production wells, so long as production wells are not damaged by borehole deviation. Projected locations of some lateral-intrusion observation wells may be precluded and require adjustment. Depths of upconing and lateral-intrusion observation wells may also require adjustment to be within the same aquifer as their corresponding production wells. Existing unused wells can be adapted as observation wells if differences from specified locations and construction are kept to a minimum and are accounted for. Where multiple production wells are in proximity, a modified monitoring approach may be needed to determine their net effect on changes in chloride concentration, and may require more than one lateral-intrusion observation well depending on the vertical positions of production-well screened intervals.

Virginia↗
USGS2024

Prototyping structured decision making for water resource management in the San Francisco Bay-Delta

A structured decision making (SDM) approach can help evaluate tradeoffs between conservation and human-benefit objectives by fostering communication and knowledge transfer among stakeholders, decision makers, and the public. However, the process is iterative and completing the full process may take years. It can be difficult to initiate an SDM effort when problems seem insurmountable. Occasionally, SDM may not even be the best or correct approach for addressing the conservation problem at hand. We describe the implementation of an SDM process to help inform difficult decisions related to competing objectives. We convened a diverse stakeholder group from the largest estuary in the western United States; the San Francisco Bay and Sacramento-San Joaquin Delta (Bay-Delta). The stakeholder group consisted of representatives from local, state, and federal agencies, non-profit organizations, and recreational fishers. The stakeholder group agreed on a problem statement and identified four priority objectives related to Chinook salmon, delta smelt, water availability and reliability, and agricultural water use. Furthermore, they proposed 14 candidate management actions to achieve their objectives. The group then used existing quantitative models and data to evaluate trade-offs in proposed management actions to identify areas of agreement of proposed candidate actions. The clear communication of the problem statement and objectives among the stakeholder group, along with evaluation of tradeoffs and uncertainty via decision-support models suggest that a full SDM approach may work in the Bay-Delta. We further communicate lessons learned during our implementation of SDM to help guide future SDM efforts in the region and elsewhere.

California↗
USGS2019

Understanding conservation decisions of agriculture producers

Most land in the United States (US) is privately owned and used for agriculture. To address the effect of agriculture on wildlife, conservation professionals and organizations need to understand the land use decisions made by farmers and ranchers. We developed a tool for categorizing farmers and ranchers by their conservation land use values (LUVs) to understand how those values affect their land use motivations and resultant decisions. We defined land as the whole natural environment including soil, water, plants, fish, and wildlife. We used principal axis factoring and reliability analysis to identify statements representing human-centered values and nature-centered values of farmers and ranchers. We tested the validity of the combined statements with a survey of South Dakota’s private landowners (N = 4,000, [Jan through May 2016]) resulting in the LUV scale. Crossing the average scores on the human-centered and nature-centered statements identified 4 LUV types: humans first (20%), nature first (29%), interconnected (29%), and disconnected (22%). Analysis of variance and chi-square tests showed that, compared to the humans first and disconnected LUV types, the nature first and interconnected LUV types reported significantly greater importance of the following: most categories of types of wildlife in their land use decisions; conservation-related motivations for participating in a United States Farm Bill Conservation Program; conservation-related motivations for land use decisions; and participation in conservation-related behaviors. Conservation professionals and organizations may use the LUV scale to better understand landowners’ land use decisions to evaluate and inform conservation policy, programs, messaging, and improve conservation outcomes.

Journal of Wildlife Management↗
USGS2023

Blue carbon in a changing climate and a changing context

Blue carbon, a convenient term to encompass the climate mitigation value of coastal carbon dynamics, has received global policy attention and growing datasets to support management actions. Carbon stock assessments in mangroves, seagrass, and tidal marshes document significant carbon storage in soils. Models illustrate significant downward fluxes of carbon dioxide and limited methane emissions, making tidal wetland preservation and restoration notably potent for carbon dioxide removal (CDR). Natural variation in different carbon stocks and fluxes has led to prioritization efforts to characterize coastal lands across physical and biological gradients. However, a larger concern beyond upscaling carbon dynamics is the resilience of these stocks and fluxes with global changes. Data-informed models have greatly improved our assessments of the vulnerability of soil and biomass stocks, greenhouse gas (GHG) balance, and spatial extents. Accelerated sea-level rise is increasingly concerning, but its impacts vary by resilience context, as very few coastal lands are without direct human impact. As the landscape context has changed, blue carbon fluxes have also shifted in terms of importance and distribution. New incentives for tidal ecosystem management are expanding boundaries to include algal carbon and tidal transport of alkalinity, which bring additional co-benefits to coastal waters. Using examples from the conterminous USA on blue carbon stocks, radiative balance, and extent, this chapter explores timelines of physical and biogeochemical stressors and their application to past, current, and future climate mitigation functions of coastal ecosystems.

Book chapter↗
USGS2012

Ecosystem services from converted land: the importance of tree cover in Amazonian pastures

Deforestation is responsible for a substantial fraction of global carbon emissions and changes in surface energy budgets that affect climate. Deforestation losses include wildlife and human habitat, and myriad forest products on which rural and urban societies depend for food, fiber, fuel, fresh water, medicine, and recreation. Ecosystem services gained in the transition from forests to pasture and croplands, however, are often ignored in assessments of the impact of land cover change. The role of converted lands in tropical areas in terms of carbon uptake and storage is largely unknown. Pastures represent the fastest-growing form of converted land use in the tropics, even in some areas of rapid urban expansion. Tree biomass stored in these areas spans a broad range, depending on tree cover. Trees in pasture increase carbon storage, provide shade for cattle, and increase productivity of forage material. As a result, increasing fractional tree cover can provide benefits land managers as well as important ecosystem services such as reducing conversion pressure on forests adjacent to pastures. This study presents an estimation of fractional tree cover in pasture in a dynamic region on the verge of large-scale land use change. An appropriate sampling interval is established for similar studies, one that balances the need for independent samples of sufficient number to characterize a pasture in terms of fractional tree cover. This information represents a useful policy tool for government organizations and NGOs interested in encouraging ecosystem services on converted lands. Using high spatial resolution remotely sensed imagery, fractional tree cover in pasture is quantified for the municipality of Rio Branco, Brazil. A semivariogram and devolving spatial resolution are employed to determine the coarsest sampling interval that may be used, minimizing effects of spatial autocorrelation. The coarsest sampling interval that minimizes spatial dependence was about 22 m. The area-weighted fractional tree cover for the study area was 1.85 %, corrected for a slight bias associated with the coarser sampling resolution. The pastures sampled for fractional tree cover were divided between ‘high’ and ‘low’ tree cover, which may be the result of intentional incorporation of arboreal species in pasture. Further research involving those ranchers that have a higher fractional tree cover may indicate ways to promote the practice on a broader scale in the region.

Urban Ecosystems↗
USGS1977

Conversion factors: SI metric and U.S. customary units

The policy of the U.S. Geological Survey is to foster use of the International System of Units (SI) which was defined by the 11th General Conference of Weights and Measures in 1960. This modernized metric system constitutes an international "language" by means of which communications throughout the world's scientific and economic communities may be improved. This publication is designed to familiarize the reader with the SI units of measurement that correspond to the common units frequently used in programs of the Geological Survey. In the near future, SI units will be used exclusively in most publications of the Survey; the conversion factors provided herein will help readers to obtain a "feel" for each unit and to "think metric."

General Information Product↗
USGS2012

Climate change and human health: Spatial modeling of water availability, malnutrition, and livelihoods in Mali, Africa

This study develops a novel approach for projecting climate trends in the Sahel in relation to shifting livelihood zones and health outcomes. Focusing on Mali, we explore baseline relationships between temperature, precipitation, livelihood, and malnutrition in 407 Demographic and Health Survey (DHS) clusters with a total of 14,238 children, resulting in a thorough spatial analysis of coupled climate-health dynamics. Results suggest links between livelihoods and each measure of malnutrition, as well as a link between climate and stunting. A ‘front-line’ of vulnerability, related to the transition between agricultural and pastoral livelihoods, is identified as an area where mitigation efforts might be usefully targeted. Additionally, climate is projected to 2025 for the Sahel, and demographic trends are introduced to explore how the intersection of climate and demographics may shift the vulnerability ‘front-line’, potentially exposing an additional 6 million people in Mali, up to a million of them children, to heightened risk of malnutrition from climate and livelihood changes. Results indicate that, holding constant morbidity levels, approximately one quarter of a million children will suffer stunting, nearly two hundred thousand will be malnourished, and over one hundred thousand will become anemic in this expanding arid zone by 2025. Climate and health research conducted at finer spatial scales and within shorter projected time lines can identify vulnerability hot spots that are of the highest priority for adaptation interventions; such an analysis can also identify areas with similar characteristics that may be at heightened risk. Such meso-scale coupled human-environment research may facilitate appropriate policy interventions strategically located beyond today’s vulnerability front-line.

Applied Geography↗
USGS1983

Evaluating environmental and economic consequences of alternative pest management strategies: results of modeling workshops

The U.S. Environmental Protection Agency (EPA) needs a comprehensive method to evaluate the human health and environmental effects of alternative agricultural pest management strategies. This project explored the utility of Adaptive Environmental Assessment (AEA) techniques for meeting this need. The project objectives were to produce models for environmental impact analysis, improve communications, identify research needs and data requirements, and demonstrate a process for resolving conflicts. The project was structured around the construction (in an initial 2 1/2-day workshop) and examination (in a second 2 1/2-day workshop) of a simulation model of a corn agroecosystem. The model conceptualized at the first workshop simulates the effect of corn agrecosystem decisions on crop production, economic returns, and environmental indicators. The model is composed of five interacting submodels: 1) a Production Strategies submodel which makes decisions concerning tillage, planting, fertilizer and pesticide applications, and harvest; 2) a Hydrology/Chemical Transport submodel which represents soil hydrology, erosion, and concentrations of fertilizers and pesticides in the soil, runoff, surface waters, and percolation; 3) a Vegetation submodel which simulates growth of agricultural crops (corns and soybeans) and weeds; 4) a Pests submodel which calculates pest population levels and resulting crop damage; and 5) an Environmental Effects submodel which calculates indicators of potential fish kills, human health effects, and wildlife habitat. The most persistent data gaps encountered in quantifying the model were coefficients to relate environmental consequences to alternative pest management strategies. While the model developed in the project is not yet accurate enough to be used for real-world decisions about the use of pesticides on corn, it does contain the basic structure upon which such a model could be built. More importantly at this stage of development, the project has shown that very complex systems can be modeled in short periods of time and that the process of building such models increases understanding among disciplinary specialists and between diverse institutional interests. This process can be useful to EPA as the agency cooperates with other institutions to meet its responsibilities in less costly ways. Activities at the second 2 1/2-day workshop included a review of the model, incorporation of necessary corrections, simulation of policy scenarios, and examination of techniques to address remaining institutional conflicts. Participants were divided into three groups representing environmental, production or industry, and regulatory interests. Each group developed scenarios that would be most appealing to their particular interest and the scenarios were simulated by the agroecosystem computer model. Negotiators from each of the interest groups decided whether a hypothetical herbicide should be relabeled and if certain restrictions should be imposed on its use. Other participants functioned as experts and consultants on caucus teams. A solution to the hypothetical problem was successfully negotiated. Workshop participants and project staff agreed that the model and processes developed during the project should be used in training students, extension specialists, farmers, researchers, and chemical producers in collaborative problem solving methods. More productive research can be planned, and more realistic models of complex systems can be built in this way. More importantly, greater trust of decisionmakers in computer models, better understanding by technical experts about disciplines other than their own, and improved cooperation between institutional interests can be achieved. This trust, understanding, and cooperation are critical ingredients in solving problems that are too complex to be resolved by independent disciplinary activity and unilateral decision authority.

Report↗
USGS2024

Need and vision for global medium-resolution Landsat and Sentinel-2 data products

Global changes in climate and land use are threatening natural ecosystems, biodiversity, and the ecosystem services people rely on. This is why it is necessary to track and monitor spatiotemporal change at a level of detail that can inform science, management, and policy development. The current constellation of multiple Landsat and Sentinel-2 satellites collecting imagery at predominantly ≤ "> ≤ 30-m spatial resolution affords an opportunity for the generation of global medium- resolution products every few days. Our goal is to both identify the information needs and provide direction towards the generation of a suite of global, high-level, systematically-generated, medium-resolution products designed for both management and science. Our vision builds on the success of the NASA MODIS/VIIRS product suite, while recognizing the unique strengths of medium-resolution satellite data given their higher spatial resolution and longer time series. We propose a suite of 13 essential products that enable the characterization of the current state and changes in the biosphere, cryosphere, and hydrosphere, and would fill information needs identified by the Committee on Earth Observation Satellites for the Global Climate Observing System and the Global Terrestrial Observing System, by the National Research Council of the US National Academies in the decadal survey, and by others. These products are: land cover, land cover change, burned area, forest loss, vegetation indices, phenology, dynamic habitat indices, albedo, land surface temperature, snow cover, ice extent, surface water extent, and evapotranspiration. Furthermore, we provide a list of desirable products poised for addition to the essential products (e.g., crop type, emissivity, and ice sheet velocity). Lastly, we suggest aspirational products requiring further algorithm development (e.g., forest structure and crop yield). For the identified essential products, algorithms are in place, making it feasible to begin generating products systematically. These products should be accompanied by quality and accuracy assessments undertaken following consensus protocols. Five decades after the first Landsat satellite, and two decades after the MODIS products were first produced, it is time now for readily available, standardized, and consistent high-level products built upon medium-resolution imagery, thereby fulfilling the promise and the vision that inspired the Landsat program since its inception.

Remote Sensing of Environment↗
USGS2011

Natural resource mitigation, adaptation and research needs related to climate change in the Great Basin and Mojave Desert

This report synthesizes the knowledge, opinions, and concerns of many Federal and State land managers, scientists, stakeholders, and partners from a workshop, held at the University of Nevada, Las Vegas, on April 20-22, 2010. Land managers, research scientists, and resource specialists identified common concerns regarding the potential effects of climate change on public lands and natural resources in the Great Basin and Mojave Desert and developed recommendations for mitigation, adaptation, and research needs. Water and, conversely, the effects of drought emerged as a common theme in all breakout sessions on terrestrial and aquatic species at risk, managing across boundaries, monitoring, and ecosystem services. Climate change models for the southwestern deserts predict general warming and drying with increasing precipitation variability year to year. Scientists noted that under these changing conditions the past may no longer be a guide to the future in which managers envision increasing conflicts between human water uses and sustaining ecosystems. Increasing environmental stress also is expected as a consequence of shifting ecosystem boundaries and species distributions, expansion of non-native species, and decoupling of biotic mutualisms, leading to increasingly unstable biologic communities. Managers uniformly expressed a desire to work across management and agency boundaries at a landscape scale but conceded that conflicting agency missions and budgetary constraints often impede collaboration. More and better science is needed to cope with the effects of climate change but, perhaps even more important is the application of science to management issues using the methods of adaptive management based on long-term monitoring to assess the merits of management actions. Access to data is essential for science-based land management. Basic inventories, spatial databases, baseline condition assessments, data quality assurance, and data sharing were identified as top information priorities by all participants at this workshop. Optimizing the utility of ecosystem monitoring data will require standardizing monitoring protocols across agencies. Better communication among researchers and managers and cooperation through partnerships to manage resources across boundaries were emphasized as necessary for adapting to changing climatic conditions. However, even these strategies may be insufficient unless policy mandates, agency missions, and funding are coordinated at a high level.

Scientific Investigations Report↗
USGS2024

Life on land needs fresh water (SDG 15)

Terrestrial ecosystems, such as forests, and the inland waters within them, such as bogs, floodplains, lakes, rivers, springs, and wetlands, are foundational for life on earth. They provide critical ecosystem services such as carbon storage and sequestration, clean water, primary production, pollination, soil fertility, and erosion control. The human footprint on terrestrial and freshwater ecosystems continues to expand, imposing pressures from deforestation, invasive species, climate change, overexploitation of species, and land conversion for agricultural production. The United Nations’ Sustainable Development Goal (SDG) 15 (Life on Land) aims to address these changes by promoting the protection, restoration, and sustainable use of terrestrial ecosystems globally. Freshwater ecosystem services and freshwater biological diversity are inherently part of, and critical to, achieving SDG 15; yet they remain absent from the goal and largely hidden within the targets and indicators. Here, we aim to highlight the role and importance of freshwater ecosystems in achieving SDG 15. We identify the six major themes of SDG 15 in which freshwater ecosystems have a preeminent role: (1) increasing protected areas, (2) sustainably managing forests, (3) reducing land degradation, (4) protecting threatened and trafficked species, (5) reducing invasive species, and (6) mobilizing resources. For each theme, we detail (a) freshwater connections to the topic, (b) key opportunities in addressing freshwater components, and (c) a relevant case study highlighting cobenefits for terrestrial ecosystems from actions targeting freshwater ecosystems. We conclude with opportunities for integrative terrestrial–aquatic monitoring, management, and policy actions. Ultimately, achieving the targets of SDG 15 requires recognition of terrestrial–aquatic interdependencies and prioritization of freshwater ecosystems and biodiversity.

Book chapter↗