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At least 973 records · Page 54Linked to original sources

A U.S.-China EcoPartnership study of disturbed wetland vegetation in West Dongting Lake, China

West Dongting Lake in China is important for human livelihoods and habitat of migratory waterfowl and other wildlife. The waterway re-engineering and agriculture intensification have contributed to changes in hydrology, sediment, and vegetation on the floodplain. This paper describes an EcoPartnership program conducted by the U.S. Geological Survey, Wetland and Aquatic Research Center, and Beijing Forestry University. It focused on the development of a wetland ecosystem network in West Dongting Lake with technical support from the U.S. partner using a number of related studies to examine wetland vegetation dynamics from upstream to downstream along the tributaries. The results of U.S. studies showed that the regeneration potential of species might be altered by changes in climate and local environment, and seed bank depletion by germination may be a major conservation threat in a future with recurring droughts in swamps of the southeastern United States. In the monsoonal wetlands of West Dongting Lake, the soil seed bank could be used as a seed source for revegetation after hydrologic restoration with the introduction of certain foundational species and the removal of poplar plantations. Also, West Dongting Lake is at high ecological risk of mercury pollution. Wetland ecosystem monitoring may allow managers to use the information to predict effects of climate change, water level and flow changes on sedimentation, and to manage for desired vegetation to support waterfowl and ecosystem services. The cooperation of two countries through the EcoPartnership program is now well established and poised for extensive research projects in the future.

West Dongting Lake↗

The role of remote sensing observations and models in hydrology: The science of evapotranspiration

Over 15 years ago, Morton (1994) summarized the state of evapotranspiration (ET) research pessimistically: ‘There have been few significant advances in our knowledge of evaporation on an environmental scale over the past four decades, a state of affairs linked to the current sterility of hydrology and related environmental sciences. Furthermore, almost none of the advances have been used successfully in practice.’ He did not foresee the rapid progress in the ensuing years. These advances can be attributed largely to three convergent themes: 1) technical innovation; 2) synergy between disciplines; and 3) expressed need. The papers in this special issue address all of these three themes on remote sensing methods for ET estimation.

Hydrological Processes↗

Book review: Inside the Equal Access to Justice Act: Environmental litigation and the crippling battle over America's lands, endangered species, and critical habitats

Inside the Equal Access to Justice Act is authored by Lowell E. Baier, an attorney, political scientist, and historian whose conservation portfolio includes the J. N. “Ding” Darling Conservation Award from the National Wildlife Federation (2016), Citizen Conservationist Award from the Association of Fish and Wildlife Agencies (2013), Conservationist of the Year Award from Outdoor Life magazine (2010), and Conservationist of the Year Award from the National Fish and Wildlife Foundation (2008). In the book, Baier stresses the need to reform the Equal Access to Justice Act (EAJA) because of unintended provisions that incentivize and reward environmental litigants for filing suit against federal regulatory and land management agencies, consequentially hindering pro-active, cooperative, conservation efforts. The book is the culmination of several years of legal research, case history analyses, and personal interviews with several key individuals from congress, conservation management agencies, and non-government organizations. Review info: Inside the equal access to justice act: Environmental litigation and the crippling battle over America's lands, endangered species, and critical habitats. By Lowell E. Baier, 2016. ISBN: 978-1442257443, 678 pp.

Journal of Wildlife Management↗

Semiautomated process for enumeration of fishes from recreational-grade side-scan sonar imagery

The use of hydroacoustic techniques is increasing as scientists search for less invasive ways to monitor fish populations, and using recreational side‐scan sonar (SSS) imagery for monitoring has become more common in aquatic resource management over the last 15 years due in part to its low cost and user‐friendly interface. The time‐consuming nature of manually counting fish targets has limited the use of the data that is collected by these systems in research or management contexts. To reduce the time and effort that is required to enumerate acoustic targets that are presumed to be fish, we developed a semiautomated process that rapidly quantifies targets from recreational SSS imagery by using an open‐source image processing software. Perceived fish targets were enumerated using a set of macroinstructions that performed similarly to manual enumeration by three experienced assessors. This method reduced variation that arises from individual assessors and eliminated the prohibitive time constraints that are associated with manual processing. Herein, we describe how our semiautomated process could be used in fisheries management contexts after further research and development of sampling methods. Future research will focus on field validation, quantifying relative abundance, testing across a broader range of environmental conditions, and exploring other applications for fisheries management.N

North American Journal of Fisheries Management↗

Subsidies from anadromous sea lamprey ( Petromyzon marinus ) carcasses function as a reciprocal nutrient exchange between marine and freshwaters

Nutrient and energy flows across ecosystem boundaries subsidize recipient communities and influence bottom‐up processes in food webs. Migratory fish such as anadromous sea lamprey provide a pulse of marine‐derived nutrients and energy to Atlantic coastal streams in spring when organisms would otherwise be subject to limiting resources. We conducted sea lamprey carcass addition experiments to characterize the role of subsidies on producer and consumer trophic pathways by manipulating subsidy quantity and light exposure. We demonstrated that producer and decomposer productivity is constrained by nutrients during spring; however, these limitations were reduced in producers as light limitations intensified through riparian shading. We observed no significant effects of increasing carcass subsidies on producer and decomposer biomass. Our results suggest that high densities of carcass subsidies may stimulate primary productivity; however, these effects are mediated by the degree of riparian shading, which demonstrated a onefold to fourfold difference in biomass accrual. In addition, sea lamprey carcass nutrients were captured by larval conspecifics. Stable isotopes analysis demonstrated that adult sea lamprey carcass tissue was relatively enriched in 15 N and 13 C isotopes compared with larvae. We observed significant enrichment in the 13 C isotope among larvae sampled after 2 and 4 weeks of exposure to adult carcass nutrients. Our work suggests that a portion of sea lamprey subsidies serve as a reciprocal exchange between freshwaters and the ocean. We highlight that this cross‐ecosystem linkage is likely influenced by subsidy quantity from donor systems and is mediated by environmental characteristics affecting the recipient system.

River Research and Applications↗

The use of boundary-spanning organizations to bridge the knowledge-action gap in North America

The goals of boundary-spanning organizations include communicating among researchers, stakeholders, and resource managers to improve decision-making. These efforts span public agencies, environmental non-governmental organizations, and private stakeholders and occur throughout Canada, the USA, and Mexico. We describe how the core philosophy of boundary-spanning organizations may help address conservation challenges in these countries. We profile a subset of the more than 100 boundary-spanning organizations, identifying some of their core accomplishments and the challenges they face. Scientific information generally is acknowledged as useful to resource management by recipients of the information. It is more difficult to infer whether the information transmitted by boundary-spanning organizations contributed to conservation decisions or whether the outcomes of those decisions differed from the potential outcomes in the absence of such information. Several examples of sustained enthusiasm for boundary-spanning efforts indicate that the organizations help to bridge the knowledge to action gap in North America.

Book chapter↗

Understanding environmental DNA detection probabilities: A case study using a stream-dwelling char Salvelinus fontinalis

Environmental DNA sampling (eDNA) has emerged as a powerful tool for detecting aquatic animals. Previous research suggests that eDNA methods are substantially more sensitive than traditional sampling. However, the factors influencing eDNA detection and the resulting sampling costs are still not well understood. Here we use multiple experiments to derive independent estimates of eDNA production rates and downstream persistence from brook trout ( Salvelinus fontinalis ) in streams. We use these estimates to parameterize models comparing the false negative detection rates of eDNA sampling and traditional backpack electrofishing. We find that using the protocols in this study eDNA had reasonable detection probabilities at extremely low animal densities (e.g., probability of detection 0.18 at densities of one fish per stream kilometer) and very high detection probabilities at population-level densities (e.g., probability of detection > 0.99 at densities of ≥ 3 fish per 100 m). This is substantially more sensitive than traditional electrofishing for determining the presence of brook trout and may translate into important cost savings when animals are rare. Our findings are consistent with a growing body of literature showing that eDNA sampling is a powerful tool for the detection of aquatic species, particularly those that are rare and difficult to sample using traditional methods.

Montana↗

The added value of time-variable microgravimetry to the understanding of how volcanoes work

During the past few decades, time-variable volcano gravimetry has shown great potential for imaging subsurface processes at active volcanoes (including some processes that might otherwise remain “hidden”), especially when combined with other methods (e.g., ground deformation, seismicity, and gas emissions). By supplying information on changes in the distribution of bulk mass over time, gravimetry can provide information regarding processes such as magma accumulation in void space, gas segregation at shallow depths, and mechanisms driving volcanic uplift and subsidence. Despite its potential, time-variable volcano gravimetry is an underexploited method, not widely adopted by volcano researchers or observatories. The cost of instrumentation and the difficulty in using it under harsh environmental conditions is a significant impediment to the exploitation of gravimetry at many volcanoes. In addition, retrieving useful information from gravity changes in noisy volcanic environments is a major challenge. While these difficulties are not trivial, neither are they insurmountable; indeed, creative efforts in a variety of volcanic settings highlight the value of time-variable gravimetry for understanding hazards as well as revealing fundamental insights into how volcanoes work. Building on previous work, we provide a comprehensive review of time-variable volcano gravimetry, including discussions of instrumentation, modeling and analysis techniques, and case studies that emphasize what can be learned from campaign, continuous, and hybrid gravity observations. We are hopeful that this exploration of time-variable volcano gravimetry will excite more scientists about the potential of the method, spurring further application, development, and innovation.

Earth-Science Reviews↗

Modeling areal measures of campsite impacts on the Appalachian National Scenic Trail to enhance ecological sustainability

Campsite impacts in protected natural areas are most effectively minimized by a containment strategy that focuses use on a limited number of sustainable campsites that spatially concentrate camping activities. This research employs spatial autoregressive (SAR) modeling to evaluate the relative influence of use-related, environmental, and managerial factors on two salient measures of campsite impact. Relational analyses examined numerous field-collected and GIS-derived indicators, including several new indicators calculated using high-resolution Light Detection and Ranging (LiDAR) topographic data to evaluate the influence of terrain characteristics on the dependent variables. Chosen variables in the best SAR models explained 35% and 30% of the variation in campsite size and area of vegetation loss on campsites. Results identified three key indicators that managers can manipulate to enhance the sustainability of campsites: campsite type, and terrain characteristics relating to landform slope and topographic roughness. Results support indirect management methods that rely on the location, design, construction, and maintenance of campsites, instead of direct regulations that restrict visitation or visitor freedoms. As visitation pressures continue to increase, this knowledge can be applied to select and promote the use of more ecologically sustainable campsites.

Connecticut, Georgia, Maine, Maryland, Massachuset↗

A multi-decadal geochemical record from Rano Aroi (Easter Island/Rapa Nui): Implications for the environment, climate and humans during the last two millennia

The small and remote Easter Island (Rapa Nui) has a complex and still partially unknown history of human colonization and interactions with the environment. Previous research from sedimentary archives collected in the three freshwater bodies of Rapa Nui document dramatic environmental changes over the last two millennia. Yet, the characteristics of sediments and paleoenvironmental records are challenging to interpret, mainly due to poor temporal resolution, hiatuses and sediment mixing. In this study, we reconstruct past changes in lithogenic inputs, weathering processes, redox conditions, productivity and water levels in the Rano Aroi wetland over the last 2000 years through the determination of major, trace and rare earth elements in a new peat core collected in 2017. The chronology is based on 8 14 C AMS dates for the upper 1.5 m and provides decadal to multi-decadal resolution which is unprecedented for the island of Rapa Nui. The multielemental proxies depict seven distinct chronological phases marked by well-defined geochemical transitions. With only a few minor fluctuations, climate conditions were dry and the mire was mildly anoxic during the first millennium (0–1000 CE) to the arrival of the first Polynesians in Rapa Nui (800–1300 CE) and until ∼1400 CE, followed by wetter conditions afterwards. The record documents with unprecedented accuracy and resolution intense droughts occurring during the middle Little Ice Age between 1520 and 1710 CE, which may have been exacerbated by human activities and triggered dramatic cultural shifts. During the interval of first contact between the Rapanuis and Europeans, the climate changed to wetter conditions, followed by intense precipitations between 1790 and 1900 CE.

Quaternary Science Reviews↗

Assessing conceptual models for subsurface reactive transport of inorganic contaminants

In many subsurface situations where human health and environmental quality are at risk (e.g., contaminant hydrogeology petroleum extraction, carbon sequestration, etc.),scientists and engineers are being asked by federal agency decision-makers to predict the fate of chemical species under conditions where both reactions and transport are processes of first-order importance. In 2002, a working group (WG) was formed by representatives of the U.S. Geological Survey, Environmental Protection Agency, Department of Energy Nuclear Regulatory Commission, Department of Agriculture, and Army Engineer Research and Development Center to assess the role of reactive transport modeling (RTM) in addressing these situations. Specifically the goals of the WG are to (1) evaluate the state of the art in conceptual model development and parameterization for RTM, as applied to soil,vadose zone, and groundwater systems, and (2) prioritize research directions that would enhance the practical utility of RTM.

Eos, Transactions, American Geophysical Union↗

Polar bears from space: Assessing satellite imagery as a tool to track Arctic wildlife

Development of efficient techniques for monitoring wildlife is a priority in the Arctic, where the impacts of climate change are acute and remoteness and logistical constraints hinder access. We evaluated high resolution satellite imagery as a tool to track the distribution and abundance of polar bears. We examined satellite images of a small island in Foxe Basin, Canada, occupied by a high density of bears during the summer ice-free season. Bears were distinguished from other light-colored spots by comparing images collected on different dates. A sample of ground-truthed points demonstrated that we accurately classified bears. Independent observers reviewed images and a population estimate was obtained using mark- recapture models. This estimate (N: 94; 95% Confidence Interval: 92-105) was remarkably similar to an abundance estimate derived from a line transect aerial survey conducted a few days earlier (N: 102; 95% CI: 69-152). Our findings suggest that satellite imagery is a promising tool for monitoring polar bears on land, with implications for use with other Arctic wildlife. Large scale applications may require development of automated detection processes to expedite review and analysis. Future research should assess the utility of multi-spectral imagery and examine sites with different environmental characteristics.

PLoS ONE↗

U.S. Geological Survey activities related to American Indians and Alaska Natives: Fiscal years 2007 and 2008

In the late 1800s, John Wesley Powell, the second director of the U.S. Geological Survey (USGS), followed his interest in the tribes of the Great Basin and Colorado Plateau and studied their cultures, languages, and surroundings. From that early time, the USGS has recognized the importance of Native knowledge and living in harmony with nature as complements to the USGS mission to better understand the Earth. Combining traditional ecological knowledge with empirical studies allows the USGS and Native American governments, organizations, and people to increase their mutual understanding and respect for this land. The USGS is the earth and natural science bureau within the U.S. Department of the Interior (DOI) and is not responsible for regulations or land management. Climate change is a major current issue affecting Native lives and traditions throughout the United States. Climate projections for the coming century indicate an increasing probability for more frequent and more severe droughts in the Southwest, including the Navajo Nation. Erosion has claimed Native homes in Alaska. Fish have become inedible due to diseases that turn their flesh mushy. Native people who rely on or who are culturally sustained by hunting, fishing, and using local plants are living with climate change now. The traditional knowledge of Native peoples enriches and confirms the work of USGS scientists. The results are truly synergistic-greater than the sum of their parts. Traditional ecological knowledge is respected and increasingly used in USGS studies-when the holders of that knowledge choose to share it. The USGS respects the rights of Native people to maintain their patrimony of traditional ecological knowledge. The USGS studies can help Tribes, Native organizations, and natural resource professionals manage Native lands and resources with the best available unbiased data and information that can be added to their traditional knowledge. Wise Native leaders have noted that traditional ecological knowledge includes the connections between Earth and her denizens. From this perspective, it is the connections among these ?relatives? that needs to be nurtured. This perspective on nature is finding new adherents among Natives and non-Natives as understanding of climate change and other environmental conditions deepens. Although this report uses the term ?resources,? the USGS, through its interdisciplinary research, acknowledges the interconnectedness of the Earth and the things that live upon it.

Circular↗

Land-margin ecosystem hydrologic data for the coastal Everglades, Florida, water years 1996-2012

Mangrove forests and salt marshes dominate the landscape of the coastal Everglades (Odum and McIvor, 1990). However, the ecological effects from potential sea-level rise and increased water flows from planned freshwater Everglades restoration on these coastal systems are poorly understood. The National Park Service (NPS) proposed the South Florida Global Climate Change Project (SOFL-GCC) in 1990 to evaluate climate change and the effect from rising sea levels on the coastal Everglades, particularly at the marsh/mangrove interface or ecotone (Soukup and others, 1990). A primary objective of SOFL-GCC project was to monitor and synthesize the hydrodynamics of the coastal Everglades from the upstream freshwater marsh to the downstream estuary mangrove. Two related hypotheses were set forward (Nuttle and Cosby, 1993): 1. There exists hydrologic conditions (tide, local rainfall, and upstream water deliveries), which characterize the location of the marsh/mangrove ecotone along the marine and terrestrial hydrologic gradient; and 2. The marsh/mangrove ecotone is sensitive to fluctuations in sea level and freshwater inflow from inland areas. Hydrologic monitoring of the SOFL-GCC network began in 1995 after startup delays from Hurricane Andrew (August 1992) and organizational transfers from the NPS to the National Biological Survey (October 1993) and the merger with the U.S. Geological Survey (USGS) Biological Research Division in 1996 (Smith, 2004). As the SOFL-GCC project progressed, concern by environmental scientists and land managers over how the diversion of water from Everglades National Park would affect the restoration of the greater Everglades ecosystem. Everglades restoration scenarios were based on hydrodynamic models, none of which included the coastal zone (Fennema and others, 1994). Modeling efforts were expanded to include the Everglades coastal zone (Schaffranek and others, 2001) with SOFL-GCC hydrologic data assisting the ecological modeling needs. In 2002, as a response for a more interdisciplinary science approach to understanding the coastal Everglades ecological system, the SOFL-GCC hydrology project was integrated into the “Dynamics of Land-Margin Ecosystems: Historical Change, Hydrology, Vegetation, Sediment, and Climate” study (Smith and others, 2002). Data from the ongoing study has been useful in providing an empirical hydrologic baseline for the greater Everglades ecosystem restoration science and management needs. The hydrology network consisted of 13 hydrologic gaging stations installed in the southwestern coastal region of Everglades National Park along three transects: Shark River (Shark or SH) transect, Lostmans River (Lostmans or LO) transect, and Chatham River (Chatham or CH) transect (fig. 1). There were five paired surface-water/groundwater gaging stations on the Shark transect (SH1, SH2, SH3, SH4, and SH5) and one stage gaging station (BSC) in the Big Sable Creek; four paired surface-water/groundwater gaging stations on the Lostmans transect (LO1, LO2, LO3, and LO4); and three paired surface-water/groundwater gaging stations on the Chatham transect (CH1, CH2, and CH3). Both surface-water and groundwater levels, salinities, and temperatures were monitored at the paired gaging stations. Rainfall was recorded at marsh and open canopy gaging stations. This report details the study introduction, method, and description of data collected, which are accessible through the final instantaneous hydrologic dataset stored in the USGS South Florida Information Access (SOFIA) South Florida Hydrology Database website, http://sofia.usgs.gov/exchange/sfl_hydro_data/location.html#brdlandmargin .

Florida↗

Decision support system development at the Upper Midwest Environmental Sciences Center

A Decision Support System (DSS) can be defined in many ways. The working definition used by the U.S. Geological Survey Upper Midwest Environmental Sciences Center (UMESC) is, “A spatially based computer application or data that assists a researcher or manager in making decisions.” This is quite a broad definition—and it needs to be, because the possibilities for types of DSSs are limited only by the user group and the developer’s imagination. There is no one DSS; the types of DSSs are as diverse as the problems they help solve. This diversity requires that DSSs be built in a variety of ways, using the most appropriate methods and tools for the individual application. The skills of potential DSS users vary widely as well, further necessitating multiple approaches to DSS development. Some small, highly trained user groups may want a powerful modeling tool with extensive functionality at the expense of ease of use. Other user groups less familiar with geographic information system (GIS) and spatial data may want an easy-to-use application for a nontechnical audience. UMESC has been developing DSSs for almost 20 years. Our DSS developers offer our partners a wide variety of technical skills and development options, ranging from the most simple Web page or small application to complex modeling application development.

Upper Midwest↗

Overview of the National Water-Quality Assessment Program

The Nation's water resources are the basis for life and our economic vitality. These resources support a complex web of human activities and fishery and wildlife needs that depend upon clean water. Demands for good-quality water for drinking, recreation, farming, and industry are rising, and as a result, the American public is concerned about the condition and sustainability of our water resources. The American public is asking: Is it safe to swim in and drink water from our rivers or lakes? Can we eat the fish that come from them? Is our ground water polluted? Is water quality degrading with time, and if so, why? Has all the money we've spent to clean up our waters, done any good? The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program was designed to provide information that will help answer these questions. NAWQA is designed to assess historical, current, and future water-quality conditions in representative river basins and aquifers nationwide. One of the primary objectives of the program is to describe relations between natural factors, human activities, and water-quality conditions and to define those factors that most affect water quality in different parts of the Nation. The linkage of water quality to environmental processes is of fundamental importance to water-resource managers, planners, and policy makers. It provides a strong and unbiased basis for better decisionmaking by those responsible for making decisions that affect our water resources, including the United States Congress, Federal, State, and local agencies, environmental groups, and industry. Information from the NAWQA Program also will be useful for guiding research, monitoring, and regulatory activities in cost effective ways.

Open-File Report↗

Using enclosed Y-mazes to assess chemosensory behavior in reptiles

Reptiles utilize a variety of environmental cues to inform and drive animal behavior such as chemical scent trails produced by food or conspecifics. Decrypting the scent-trailing behavior of vertebrates, particularly invasive species, enables the discovery of cues that induce exploratory behavior and can aid in the development of valuable basic and applied biological tools. However, pinpointing behaviors dominantly driven by chemical cues versus other competing environmental cues can be challenging. Y-mazes are common tools used in animal behavior research that allow quantification of vertebrate chemosensory behavior across a range of taxa. By reducing external stimuli, Y-mazes remove confounding factors and present focal animals with a binary choice. In our Y-maze studies, a scenting animal is restricted to one arm of the maze to leave a scent trail and is removed once scent-laying parameters have been met. Then, depending on the trial type, either the focal animal is allowed into the maze, or a competing scent trail is created. The result is a record of the focal animal's choice and behavior while discriminating between the chemical cues presented. Here, two Y-maze apparatuses tailored to different invasive reptile species: Argentine black and white tegu lizards (Salvator merianae) and Burmese pythons (Python bivittatus) are described, outlining the operation and cleaning of these Y-mazes. Further, the variety of data produced, experimental drawbacks and solutions, and suggested data analysis frameworks have been summarized.

Journal of Visualized Experiments↗

GeoAI for science and the science of GeoAI

This paper reviews trends in GeoAI research and discusses cutting-edge ad- vances in GeoAI and its roles in accelerating environmental and social sciences. It ad- dresses ongoing attempts to improve the predictability of GeoAI models and recent re- search aimed at increasing model explainability and reproducibility to ensure trustworthy geospatial findings. The paper also provides reflections on the importance of defining the "science" of GeoAI in terms of its fundamental principles, theories, and methods to ensure scientific rigor, social responsibility, and lasting impacts.

Journal of Spatial Information Science↗