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USGS2012

Predicting the likelihood of altered streamflows at ungauged rivers across the conterminous United States

An approach is presented in this study to aid water-resource managers in characterizing streamflow alteration at ungauged rivers. Such approaches can be used to take advantage of the substantial amounts of biological data collected at ungauged rivers to evaluate the potential ecological consequences of altered streamflows. National-scale random forest statistical models are developed to predict the likelihood that ungauged rivers have altered streamflows (relative to expected natural condition) for five hydrologic metrics (HMs) representing different aspects of the streamflow regime. The models use human disturbance variables, such as number of dams and road density, to predict the likelihood of streamflow alteration. For each HM, separate models are derived to predict the likelihood that the observed metric is greater than (‘inflated’) or less than (‘diminished’) natural conditions. The utility of these models is demonstrated by applying them to all river segments in the South Platte River in Colorado, USA, and for all 10-digit hydrologic units in the conterminous United States. In general, the models successfully predicted the likelihood of alteration to the five HMs at the national scale as well as in the South Platte River basin. However, the models predicting the likelihood of diminished HMs consistently outperformed models predicting inflated HMs, possibly because of fewer sites across the conterminous United States where HMs are inflated. The results of these analyses suggest that the primary predictors of altered streamflow regimes across the Nation are (i) the residence time of annual runoff held in storage in reservoirs, (ii) the degree of urbanization measured by road density and (iii) the extent of agricultural land cover in the river basin.

River Research and Applications↗

USGS2021

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↗

USGS2024

Atlas of microscopic images of biochar using reflected light microscopy in biochar characterization

Derived through the thermochemical conversion of biomass, biochar is a carbon-rich substance recognized for its significance in environmental applications and sustainable agriculture. As interest in its utilization continues to rise, it becomes crucial to comprehend how the source material and pyrolysis parameters influence the properties of biochar and, consequently, to research the suitability of various analytical methods for characterizing it. Despite the current utilization of numerous physical and chemical methods, the untapped potential of reflected light microscopy warrants further exploration. While a few recent studies suggest a correlation between certain microscopic characteristics and selected physical and chemical properties of biochar, the data are limited and difficult to compare. This is primarily due to variations in the types of original biomass used and lack of information about pyrolysis conditions. Moreover, because only a limited number of photographs taken under a reflected light microscope are publicly available to-date, it is difficult to evaluate morphological differences between various biochars and other organic materials such as inertinites from coal, charcoal, etc. To address limited availability of publicly available data, this “Atlas of Microscopic Images of Biochar” presents a collection of more than 300 images contributed by researchers from Poland, the United States, Canada, Australia, Brazil, and Denmark. These photomicrographs capture optical characteristics of a diverse array of biochar, demonstrating its unique morphological and structural features. This visual documentation can serve as a valuable resource for researchers, industry professionals, educators, and enthusiasts interested in investigating the complexities of biochar forms.

Indiana Journal of Earth Sciences↗

USGS2005

Early chromite mining and agricultural clearance: Opportunities for the investigation of agricultural sediment dynamics in the Eastern Piedmont (USA)

Many flood plains in the Eastern Piedmont (USA) are buried under deposits of sediment resulting from European agricultural clearance. Classic radioisotopic dating techniques cover temporal periods too short (137Cs, 210Pb) or too long (14C) to reliably date sediments deposited during periods of local European activity (1660-1900). Moreover, many potential biomarkers, such as pollen, degrade in oxic flood plain sediments. In the Baltimore, Maryland (USA) region, early chromite mining (1820 - 1880) occurred during periods of rapid agricultural clearance. Use of chromium (Cr) chemostratigraphic profiles in flood plain sediments tied to historical mining activity can provide improved precision in overbank accumulation rates and timing. Sediment cores were collected from the Red Run basin, which is part of the Baltimore Ecosystem Study, an urban Long-Term Ecological Research site. Trace metal chemostratigraphic profiles were measured and peaks in Cr concentration tied to historic mining activity. Dates from Cr chemostratigraphic profiles were combined with 137Cs dating to reconstruct flood plain sedimentation rates. Red Run early sedimentation rates (1820 - 1880) were higher (0.45 - 1.19 cm/yr) than more recent (1880 - 1963) rates (0.08 - 0.46 cm/yr). This indicates that Piedmont flood plain vertical sediment accumulation might have peaked before the peak in agricultural clearance, earlier than assumed by regional models. The Cr chemostratigraphy is applicable to a wider region including much of the Maryland and Pennsylvania (USA) Piedmont.

American Journal of Science↗

USGS2015

Response to "Comment on and Reinterpretation of Gabriel et al. (2014) "Fish Mercury and Surface Water Sulfate Relationships in the Everglades Protection Area""

The purpose of this forum is to respond to a rebuttal submitted by Julian et al., Environ Manag 55:1–5, 2015 where they outlined their overall disagreement with the data preparation, methods, and interpretation of results presented in Gabriel et al. (Environ Manag 53:583–593, 2014 ). Here, we provide background information on the research premise presented in Gabriel et al. (Environ Manag 53:583–593, 2014 ) and provide a defense for this work using five themes. In spite of what Julian et al. perceive as limitations in the sampling methods and analytical tools used for this work, the relationships found between fish total mercury and surface water sulfate concentrations in Gabriel et al. (Environ Manag 53:583–593, 2014 ) are comparable to relationships between pore water methylmercury (MeHg) and pore water sulfate found in past studies indicating that sulfate is important to MeHg production and bioaccumulation in the Everglades. Julian et al. state “…there is no way to justify any ecosystem-wide sulfur strategy as a management approach to reduce mercury risk in the (Everglades) as suggested by Gabriel et al. (Environ Manag 53:583–593, 2014 ), Corrales et al. (Sci Tot Environ 409:2156–2162, 2011 ) and Orem et al. (Rev Environ Sci Technol 41 (S1):249–288, 2011 ).” We disagree, and having stated why sulfate input reduction to the Everglades may be the most effective means of reducing mercury in Everglades fish, it is important that research on sulfur and mercury biogeochemistry continues. If further studies support the relationship between sulfate loading reduction and MeHg reduction, sulfur mass balance studies should commence to (1) better quantify agricultural and connate seawater sulfate inputs and (2) define opportunities to reduce sulfate inputs to the Everglades ecosystem.

Environmental Management↗

USGS2021

Landscape characterization of floral resources for pollinators in the Prairie Pothole Region of the United States

Across agricultural areas of the Prairie Pothole Region (PPR), floral resources are primarily found on public grasslands, roadsides, and private grasslands used as pasture or enrolled in federal conservation programs. Little research has characterized the availability of flowers across the region or identified the primary stakeholders managing lands supporting pollinators. We explored spatial and temporal variability in flower abundance and richness across multiple grassland categories (i.e. general grassland, conservation grassland, and engineered pollinator habitat) in the PPR from 2015 to 2018 and used these data to estimate the number of flowering stems present across the region on private and public land holdings. Both flowering plant abundance and richness were greatest on engineered pollinator habitat, but this land category encompassed <0.01% of the total grassland area in the PPR. There was a steady decrease in flower abundance over the growing season across all land categories. We detected considerable variation in flower abundance and richness across grassland categories, indicating that not all natural or semi-natural covers provide similar value to pollinators. At a landscape scale, large land holdings such as privately-owned grasslands and Conservation Reserve Program lands contributed the greatest number of flowers by an order of magnitude, though these lands collectively did not support the greatest abundance of flowers per unit area. Our research depicts spatial and temporal variation in pollinator resources across the region. Further, our research will assist managers and policy makers in understanding the role of public and private lands and conservation programs in supporting pollinators.

Minnesota, North Dakota, South Dakota↗

USGS2018

Environmental risks and challenges associated with neonicotinoid insecticides

Neonicotinoid use has increased rapidly in recent years, with a global shift towards insecticide applications as seed coatings rather than aerial spraying. While the use of seed coatings can lessen the amount of overspray and drift, the near universal and prophylactic use of neonicotinoid seed coatings on major agricultural crops has led to widespread detections in the environment (pollen, soil, water, honey). Pollinators and aquatic insects appear to be especially susceptible to the effects of neonicotinoids with current research suggesting that chronic sub-lethal effects are more prevalent than acute toxicity. Meanwhile, evidence of clear and consistent yield benefits from the use of neonicotinoids remains elusive for most crops. Future decisions on neonicotinoid use will benefit from weighing crop yield benefits versus environmental impacts to non-target organisms and considering whether there are more environmentally benign alternatives.

Environmental Science & Technology↗

USGS2022

Elevated nitrogen deposition to fire-prone forests adjacent to urban and agricultural areas, Colorado front range, USA

As humans increasingly dominate the nitrogen cycle, deposition of reactive nitrogen (Nr) will continue to have adverse consequences for ecosystems. In the Rocky Mountains, Nr deposition remains elevated and has become increasingly dominated by ammonium, despite efforts to reduce emissions. Currently, spatial models of Nr deposition do not fully account for urban and agricultural emissions, sources that contribute to the observed high rates of ammonium deposition in adjacent ecosystems. To address this gap in the Colorado Front Range, we measured Nr deposition along a transect from urban and agricultural plains to subalpine forests. We found elevated values of wet Nr deposition at the urban and foothill sites (4.7 and 4.4 kg N ha −1 yr −1 , respectively), and lower values at the montane and subalpine sites (2.5–2.8 kg N ha −1 yr −1 ). Ammonium dominated wet and bulk Nr deposition, accounting for approximately 69% of bulk Nr deposition. Seasonally, bulk Nr deposition was highest in the spring months, when air masses from the plains are transported west into the mountains. Previous work has demonstrated that high elevations of the Colorado Front Range are especially sensitive to Nr deposition due to thin soil and minimal vegetation. Our results indicate that despite lower precipitation, the fire-prone forested foothills receive even greater Nr deposition than higher elevations, due to proximity to urban and agricultural Nr sources. The interaction between elevated Nr deposition and wildfire in this region may pose a risk to water supplies and ecosystems, and is an important topic for future research.

Colorado↗

USGS2010

Data Used in Analyses of Trends, and Nutrient and Suspended-Sediment Loads for Streams in the Southeastern United States, 1973-2005

Water-quality data from selected surface-water monitoring sites in the Southeastern United States were assessed for trends in concentrations of nutrients, suspended sediment, and major constituents and for in-stream nutrient and suspended-sediment loads for the period 1973-2005. The area of interest includes river basins draining into the southern Atlantic Ocean, the Gulf of Mexico, and the Tennessee River-drainage basins in Hydrologic Regions 03 (South Atlantic - Gulf) and 06 (Tennessee). This data assessment is related to studies of several major river basins as part of the U.S. Geological Survey National Water-Quality Assessment Program, which was designed to assess national water-quality trends during a common time period (1993-2004). Included in this report are data on which trend tests could be performed from 44 U.S. Geological Survey National Water Information System (NWIS) sampling sites. The constituents examined include major ions, nutrients, and suspended sediment; the physical properties examined include pH, specific conductance, dissolved oxygen, and streamflow. Also included are data that were tested for trends from an additional 290 sites from the U.S. Environmental Protection Agency Storage and Retrieval (STORET) database. The trend analyses of the STORET data were limited to total nitrogen and total phosphorus concentrations. Data from 48 U.S. Geological Survey NWIS sampling sites with sufficient water-quality and continuous streamflow data for estimating nutrient and sediment loads are included. The methods of data compilation and modification used prior to performing trend tests and load estimation are described. Results of the seasonal Kendall trend test and the Tobit trend test are given for the 334 monitoring sites, and in-stream load estimates are given for the 48 monitoring sites. Basin characteristics are provided, including regional landscape variables and agricultural nutrient sources (annual variations in cropping and fertilizer use). The data and results presented in this report are in tabular format and can be downloaded and used by environmental researchers and water managers, particularly in the Southeast.

Data Series↗

USGS2007

Bathymetry of Walker Lake, West-Central Nevada

Walker Lake lies within a topographically closed basin in west-central Nevada and is the terminus of the Walker River. Much of the streamflow in the Walker River is diverted for irrigation, which has contributed to a decline in lake-surface altitude of about 150 feet and an increase in dissolved solids from 2,500 to 16,000 milligrams per liter in Walker Lake since 1882. The increase in salinity threatens the fresh-water ecosystem and survival of the Lahontan cutthroat trout, a species listed as threatened under the Endangered Species Act. Accurately determining the bathymetry and relations between lake-surface altitude, surface area, and storage volume are part of a study to improve the water budget for Walker Lake. This report describes the updated bathymetry of Walker Lake, a comparison of results from this study and a study by Rush in 1970, and an estimate of the 1882 lake-surface altitude. Bathymetry was measured using a single-beam echosounder coupled to a differentially-corrected global positioning system. Lake depth was subtracted from the lake-surface altitude to calculate the altitude of the lake bottom. A Lidar (light detection and ranging) survey and high resolution aerial imagery were used to create digital elevation models around Walker Lake. The altitude of the lake bottom and digital elevation models were merged together to create a single map showing land-surface altitude contours delineating areas that are currently or that were submerged by Walker Lake. Surface area and storage volume for lake-surface altitudes of 3,851.5-4,120 feet were calculated with 3-D surface-analysis software. Walker Lake is oval shaped with a north-south trending long axis. On June 28, 2005, the lake-surface altitude was 3,935.6 feet, maximum depth was 86.3 feet, and the surface area was 32,190 acres. The minimum altitude of the lake bottom from discrete point depths is 3,849.3 feet near the center of Walker Lake. The lake bottom is remarkably smooth except for mounds near the shore and river mouth that could be boulders, tree stumps, logs, or other submerged objects. The echosounder detected what appeared to be mounds in the deepest parts of Walker Lake, miles from the shore and river mouth. However, side-scan sonar and divers did not confirm the presence of mounds. Anomalies occur in two northwest trending groups in northern and southern Walker Lake. It is hypothesized that some anomalies indicate spring discharge along faults based on tufa-like rocks that were observed and the northwest trend parallel to and in proximity of mapped faults. Also, evaporation measured from Walker Lake is about 50 percent more than the previous estimate, indicating more water is flowing into the lake from sources other than the Walker River. Additional studies need to be done to determine what the anomalies are and whether they are related to the hydrology of Walker Lake. Most differences in surface area and storage volume between this study and a study by Rush in 1970 were less than 1 percent. The largest differences occur at lake-surface altitudes less than 3,916 feet. In general, relations between lake-surface altitude, surface area, and storage volume from Rush's study and this study are nearly identical throughout most of the range in lake-surface altitude. The lake-surface altitude in 1882 was estimated to be between 4,080 feet and 4,086 feet with a probable altitude of 4,082 feet. This estimate compares well with two previous estimates of 4,083 feet and 4,086 feet. Researchers believe the historic highstand of Walker Lake occurred in 1868 and estimated the highstand was between 4,089 feet and 4,108 feet. By 1882, Mason Valley was predominantly agricultural. The 7-26 feet decline in lake-surface altitude between 1868 and 1882 could partially be due to irrigation diversions during this time.

Scientific Investigations Report↗

USGS2017

U.S. Geological Survey—Energy and wildlife research annual report for 2017

Introduction Terrestrial and aquatic ecosystems provide valuable services to humans and are a source of clean water, energy, raw materials, and productive soils. The Nation’s food supply is more secure because of wildlife. For example, native pollinators enhance agricultural crops, and insect-eating bats provide pest control services worth billions of dollars to farmers annually. Fish and wildlife are also vital to a vibrant outdoor recreation and tourism industry. Recreational activities, such as hunting, shooting, boating, and angling, generated \$1.1 billion in excise taxes paid to State wildlife agencies in 2017. National parks, wildlife refuges, and monuments accounted for $35 billion in economic output and 318,000 jobs nationwide in 2016. Additional economic benefits are generated from the use and enjoyment of wildlife in State-owned lands and waters. Although the United States is rich in natural resources, human activity continues to place new pressures on fish and wildlife and the habitats they rely on. The United States became the world’s top producer of petroleum and natural gas products in 2012, surpassing Russia’s natural gas production levels in 2009 and Saudi Arabia’s petroleum production in 2013. The U.S. Energy Information Administration projects that the demand for liquid fuel, natural gas, and renewable energy will show strong growth in the next 20 years. Wind energy has demonstrated consistent growth since 2007 with now more than 53,000 wind turbines contributing to power grids in 41 States, Guam, and Puerto Rico. Solar energy has seen rapid growth since 2013 and made up nearly one-third of the total electricity generation additions in 2016. Yet as our Nation works to advance energy security and sustain wildlife, some conflicts have surfaced. Impacts of an expanding energy infrastructure include fragmentation and loss of habitat as well as mortality of birds, bats, fish, and other animals from interactions with energy generation facilities. Because energy development can often occur in wildlife habitats, ecological science can help guide project siting and operational decisions to areas that present the lowest risk to wildlife and energy developers. To address these challenges and make the most of new opportunities, the U.S. Geological Survey is producing innovative science to develop workable solutions that can help sustain wildlife and the habitat they rely upon, while allowing informed development.

Circular↗

USGS2003

True metabolizable energy for wood ducks from acorns compared to other waterfowl foods

Acorns of bottomland red oaks (Quercus spp.) are an important food of North American wood ducks (Aix sponsa). Barras et al. (1996) demonstrated that female wood ducks selected willow oak (Q. phellos) acorns over other species. We measured true metabolizable energy (TME) derived by captive, wild-strain, adult female wood ducks from acorns of willow oak, water oak (Q. nigra), cherrybark oak (Q. pagoda), and pin oak (Q. palustris) to determine whether female wood ducks ' preference for willow oak acorns was related to TME. Estimates of TME within acorn species were relatively precise, yet we did not detect variation in TME among acorn species (P=0.31); hence, we estimated TME across species (2.76±0.033 [SE] kcal/g dry mass; n=34). We concluded that TME apparently did not explain female wood ducks ' preference for willow oak acorns and hypothesized that morphological characteristics of willow oak acorns may be proximate cues related to selection by wood ducks . We also summarized known TME estimates for acorns fed to wood ducks and mallards (Anas platyrhynchos), and natural and agricultural foods fed to mallards, northern pintails (A. acuta), blue-winged teal (A. discors), and Canada geese (Branta canadensis). We found that acorns and moist-soil plant seeds and tubers provided, on average, about 76% of the TME in agricultural seeds. Thus, bottomland-hardwood and moist-soil habitats have potential to provide significant amounts of dietary energy , as well as greater diversity of foods and nutrients than croplands. Researchers should continue to determine TME of common foods (plant and animal) of waterfowl , and use TME in estimating waterfowl habitat carrying capacity (e.g., Reinecke et al. 1989). Additionally, large-scale, reliable estimates of plant and animal food availability in bottomland-hardwood and moist-soil habitats are needed to evaluate carrying capacity of landscapes important to waterfowl , such as the Mississippi Alluvial Valley (MAV).

Journal of Wildlife Management↗

USGS2019

Point sources and agricultural practices control spatial-temporal patterns of orthophosphate in tributaries to Chesapeake Bay

Orthophosphate (PO 4 ) is the most bioavailable form of phosphorus (P). Excess PO 4 may cause harmful algal blooms in aquatic ecosystems. A major restoration effort is underway for Chesapeake Bay (CB) to reduce P, nitrogen, and sediment loading to CB. Although PO 4 cycling and delivery to streams has been characterized in small-scale studies, regional drivers of PO 4 patterns remain poorly understood because most water quality trend assessment focus on total P. Moreover, these trend assessments are usually at an annual timestep. To address this research gap, we analyzed PO 4 patterns over a 9-year period at 53 monitoring stations across the CB watershed to: 1) characterize the role of PO 4 in total P fluxes and trends; 2) describe spatial and temporal patterns of PO 4 concentrations across seasons and streamflow ; and 3) explore factors explaining these patterns. Agricultural watersheds exported the most total P compared with watersheds under different land uses (e.g., urban or forest), with PO 4 comprising up to 50% of those exports. Although PO 4 exports are declining at many sites, some agricultural regions are experiencing increasing trends at a rate sufficient to drive total P trends. Regression modeling results suggest that point source load reductions are likely responsible for decreasing PO 4 concentrations observed at many sites. Watersheds with more Conservation Reserve Program enrollment had lower summer PO 4 concentrations, highlighting the effectiveness of this practice. Manure inputs strongly predicted PO 4 concentrations at high flows across all seasons. Both manure applications and conservation tillage were correlated with changes in PO 4 concentrations at high flow, suggesting these activities could contribute to increasing PO 4 concentrations. This study highlights the effectiveness of point source control for reducing PO 4 exports and underscores the need for management strategies to target sources, practices, and landscape factors determining PO 4 loss from soils where manure inputs remain high.

Delaware, Maryland, New York, Pennsylvania, Virgin↗

USGS2013

Selection of hyperspectral narrowbands (HNBs) and composition of hyperspectral twoband vegetation indices (HVIs) for biophysical characterization and discrimination of crop types using field reflectance and Hyperion/EO-1 data

The overarching goal of this study was to establish optimal hyperspectral vegetation indices (HVIs) and hyperspectral narrowbands (HNBs) that best characterize, classify, model, and map the world's main agricultural crops. The primary objectives were: (1) crop biophysical modeling through HNBs and HVIs, (2) accuracy assessment of crop type discrimination using Wilks' Lambda through a discriminant model, and (3) meta-analysis to select optimal HNBs and HVIs for applications related to agriculture. The study was conducted using two Earth Observing One (EO-1) Hyperion scenes and other surface hyperspectral data for the eight leading worldwide crops (wheat, corn, rice, barley, soybeans, pulses, cotton, and alfalfa) that occupy ~70% of all cropland areas globally. This study integrated data collected from multiple study areas in various agroecosystems of Africa, the Middle East, Central Asia, and India. Data were collected for the eight crop types in six distinct growth stages. These included (a) field spectroradiometer measurements (350-2500 nm) sampled at 1-nm discrete bandwidths, and (b) field biophysical variables (e.g., biomass, leaf area index) acquired to correspond with spectroradiometer measurements. The eight crops were described and classified using ~20 HNBs. The accuracy of classifying these 8 crops using HNBs was around 95%, which was ~ 25% better than the multi-spectral results possible from Landsat-7's Enhanced Thematic Mapper+ or EO-1's Advanced Land Imager. Further, based on this research and meta-analysis involving over 100 papers, the study established 33 optimal HNBs and an equal number of specific two-band normalized difference HVIs to best model and study specific biophysical and biochemical quantities of major agricultural crops of the world. Redundant bands identified in this study will help overcome the Hughes Phenomenon (or “the curse of high dimensionality”) in hyperspectral data for a particular application (e.g., biophysi- al characterization of crops). The findings of this study will make a significant contribution to future hyperspectral missions such as NASA's HyspIRI.

Africa;Central Asia;Middle East↗

USGS1998

Airborne pesticide residues along the Mississippi River

The occurrence, concentration, and geographical distribution of agricultural pesticides were determined in air over the Mississippi River from New Orleans, LA, to St. Paul, MN, during the first 10 days of June 1994. Air samples were collected from a research vessel by pulling air through polyurethane foam plugs at about 100 L/min for up to 24 h. Each sample was analyzed for 42 pesticides and 3 pesticide transformation products. Twenty-five compounds 15 herbicides, 7 insecticides, and 3 pesticide transformation products were detected in one or more samples with concentrations ranging from 0.05 to 80 ng/m 3 . Alachlor, chlorpyrifos, diazinon, fonofos, malathion, methyl parathion, metolachlor, metribuzin, pendimethalin, and trifluralin were detected in 80% or more of the samples. The highest concentrations for chlorpyrifos (1.6 ng/m 3 ), diazinon (0.36 ng/m 3 ), and malathion (4.6 ng/m 3 ) all occurred near major metropolitan areas. These samples represent a “snapshot in time”, a spatial and temporal integration of which pesticides were present in the air during each sampling period. The occurrence and atmospheric concentrations of the observed pesticides were most closely related to their use on cropland within 40 km of the river.

Mississippi River↗

USGS2016

New perspectives on a 140-year legacy of mining and abandoned mine cleanup in the San Juan Mountains, Colorado

The Gold King mine water release that occurred on 5 August 2015 near the historical mining community of Silverton, Colorado, highlights the environmental legacy that abandoned mines have on the environment. During reclamation efforts, a breach of collapsed workings at the Gold King mine sent 3 million gallons of acidic and metal-rich mine water into the upper Animas River, a tributary to the Colorado River basin. The Gold King mine is located in the scenic, western San Juan Mountains, a region renowned for its volcano-tectonic and gold-silver-base metal mineralization history. Prior to mining, acidic drainage from hydrothermally altered areas was a major source of metals and acidity to streams, and it continues to be so. In addition to abandoned hard rock metal mines, uranium mine waste poses a long-term storage and immobilization challenge in this area. Uranium resources are mined in the Colorado Plateau, which borders the San Juan Mountains on the west. Uranium processing and repository sites along the Animas River near Durango, Colorado, are a prime example of how the legacy of mining must be managed for the health and well-being of future generations. The San Juan Mountains are part of a geoenvironmental nexus where geology, mining, agriculture, recreation, and community issues converge. This trip will explore the geology, mining, and mine cleanup history in which a community-driven, watershed-based stakeholder process is an integral part. Research tools and historical data useful for understanding complex watersheds impacted by natural sources of metals and acidity overprinted by mining will also be discussed.

Colorado↗

USGS1996

The relevance of the Mediterranean Region to colonial waterbird conservation

The Mediterranean Sea is the largest partially enclosed sea in the world and provides habitat to more than 100 species of waterbirds from the Palearctic-North African-Middle Eastern regions. Even though the Mediterranean suffers from pollution, has little tidal influence, and is oligotrophic, more than half of the western Palearctic populations of numerous waterfowl species winter in the region. Thirty-three species of colonial waterbirds breed along the 46,000 km Mediterranean coastline with nine species considered threatened or endangered, mostly because of wetland loss and degradation. The long history of human activity and scientific investigations in the region has taught some valuable lessons. In the area of colonial waterbird biology and conservation, we have learned important lessons about the value of long-term monitoring and research on selected populations. From marking studies of Greater Flamingos (Phoenicopterus ruber roseus) and Little Egrets (Egretta garzetta) results have been used to derive useful information about metapopulation dynamics. Involvement of both African and European biologists allowed year-round Studies of these species that yielded valuable spin-offs for training in avian and wetland conservation. We have also learned the value of man-made wetlands as feeding and nesting sites for some colonial waterbirds. Careful evaluations of the habitat quality of different types of wetlands are required, as in contaminant levels such as lead shot and pesticides. Wetland conservationists have also learned from some instructive mistakes. Dam construction and agricultural incentive programs sponsored by the European Community, the World Bank, and others from the past have largely ignored impacts on wetlands and wildlife. In some areas, economic ventures such as aquaculture operations and salt mining have not involved waterbird habitat needs in their planning. Research and conservation needs include: (1) establishing regional monitoring programs and data banks for seabirds, wading birds, ducks, and geese; (2) implementing a wetland inventory for many Countries with little quantitative data on wetlands; (3) improving habitat quality assessments; (4) improving relationships with industry, the private citizenry, and government officials to further an appreciation for the value of wetlands and waterbirds; (5) enhancing training efforts, especially in underdeveloped Countries; (6) evaluating the effects of hunting and other disturbances to nesting and feeding waterbirds in different regions; (7) setting up 'sister-reserve' (twinned) sites in Europe and Africa to foster international linkages and training; and (8) fostering local-regional conservation programs to preserve reed beds, wet woodlots, and other key habitats.

Book chapter↗

USGS2008

Wildlife values of North American ricelands

Ricelands have become an indispensable component of waterbird habitat and a leading example of integrating agricultural and natural resource management in the Mississippi Alluvial Valley, Gulf Coast, and Central California. Residual rice, weed seeds, and invertebrates provide food for many avian species during fall and winter. In North America, considerable information exists on the use of ricefields by wintering waterbirds, the value of ricelands as breeding habitat for birds, and the effects of organic chemicals on birds that- feed in ricefields. Recent research has also examined the influence of field management practices, such as winter flooding and post-harvest straw manipulation, on the suitability of ricefields for wildlife. Whereas early studies focused on detrimental effects of wildlife on rice production (e.g., crop depredation), it has become apparent that waterbirds may benefit producers by enhancing straw decomposition, reducing weed and pest pressure, and providing additional income through hunting and wildlife viewing opportunities. A comprehensive evaluation of agronomic and environmental issues is needed to meet the challenges of producing food and sustaining wildlife in twenty-first-century rice lands. Changes in agricultural markets, pressures of increased urban development, conflicting needs for limited resources such as water, endangered species constraints, and concerns over water quality must be addressed in developing a sustainable, mutually beneficial partnership among the rice industry, wildlife, and environmental interests. Research is also needed to evaluate potential reductions in the wildlife carrying capacity of ricelands resulting from new harvest and field management techniques, crop conversion, or loss of rice acreage. Key uncertainties include: (1) changes in waste grain abundance and availability due to various harvest and post-harvest management practices; (2) evaluating food depletion by birds feeding in rice6elds and derermining threshold food levels required to maintain bird use; (3) quantifying use of ricefields by nonwaterfowl species throughout the year; and (4) determining the amount and distribution of rice habitat needed to meet objectives of the North American Waterfowl Management Plan and the United States Shorebird Conservation Plan.

Book chapter↗