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At least 1,351 records · Page 75Linked to original sources
USGS2009

Assessing the landscape context and conversion risk of protected areas using satellite data products

Since the establishment of the first national park (Yellowstone National Park in 1872) and the first wildlife refuge (Pelican Island in 1903), dramatic changes have occurred in both ecological and cultural landscapes across the U.S. The ability of these protected areas to maintain current levels of biodiversity depend, at least in part, on the integrity of the surrounding landscape. Our objective was to quantify and compare the extent and pattern of natural land cover, risk of conversion, and relationships with demographic and economic variables in counties near National Park Service units and U.S. Fish and Wildlife Service refuges with those counties distant from either type of protected area in the coterminous United States. Our results indicate that landscapes in counties within 10 km of both parks and refuges and those within 10 km of just parks were more natural, more intact, and more protected than those in counties within 10 km of just refuges and counties greater than 10 km from either protected area system. However, they also had greater human population density and change in population, indicating potential conversion risk since the percent of landscape protected averaged < 5% in both groups and human population dynamics are primary drivers of change in many landscapes. Conversion outweighed protection by at least two times (Conservation Risk Index > 2) in 76% of counties near both parks and refuges, 81% of counties near just parks, 91% of counties near just refuges, and 93% of distant counties. Thirteen percent of counties in the coterminous U.S. had moderate to high amounts of natural land cover (> 60%), low protection (< 20%), and the greatest change in population (> 20%). Although these areas are not the most critically endangered, they represent the greatest conservation opportunity, need, and urgency. Our approach is based on national level metrics that are simple, general, informative, and can be understood by broad audiences and by policy makers and managers to assess the health of lands surrounding parks and refuges. Regular monitoring of these metrics with satellite data products in counties surrounding protected areas provides a consistent, national level assessment of management opportunities and potentially adverse changes on adjacent lands.

Remote Sensing of Environment↗
USGS2010

Fluorine, fluorite, and fluorspar in central Colorado

Fluorine (F) is a widespread element that was deposited in a variety of rocks, minerals, and geologic environments in central Colorado. It occurs as a trace element, as a major component of the mineral fluorite (CaFs), and as a major economic source of fluorine in fluorspar deposits, which are massive concentrations of fluorite. This study has compiled available geochemical analyses of rocks, both unmineralized and mineralized, to determine the distribution of fluorine in specific age-lithologic categories, ranging from 1.8-giga-annum (Ga) metamorphic rocks to modern soils, throughout central Colorado. It also draws upon field studies of fluorine-rich mineral deposits, including fluorspar deposits, to decipher the nearly two-billion-year-long geologic history of fluorine in the study area, with implications for mineral-resource evaluations and exploration. The resulting compilation provides an important inventory of the naturally occurring levels and sources of fluorine that ultimately weather, erode, and become part of surface waters that are used for domestic water supplies in densely populated areas along the Colorado Front Range. Most commonly, fluorine is a trace element in virtually all rocks in the region. In the 3,798 unmineralized rocks that were analyzed for fluorine in the study area, the average fluorine content was 1,550 parts per million (ppm). The median was 640 ppm, nearly identical to the average crustal abundance of 650 ppm, and some high-fluorine rocks in the Pikes Peak area skewed the average to a value much greater than the median. Most unmineralized age-lithologic rock suites, including Proterozoic metamorphic rocks, 1.7- and 1.4-Ga granitic batholiths, Cambrian igneous rocks, Phanerozoic sedimentary rocks, and Laramide and Tertiary igneous rocks, had median fluorine values of 400 to 740 ppm fluorine. In all suites, however, a small number of analyzed samples contained more than 1 percent (10,000 ppm) fluorine. The 1.1-Ga plutonic rocks related to the Pikes Peak batholith had a mean fluorine content of 1,700 ppm, and primary magmatic fluorite and fluorite-bearing pegmatites are common throughout that igneous mass. Fluorine was deposited in many types of economic mineral deposits in central Colorado, and it currently is a significant trace element in some thermal springs. In the fluorspar deposits, fluorine contents were as high as 37 percent. Some fluorine-rich porphyry systems, such as Jamestown, had fluorine values that ranged from 200 ppm to nearly 37 percent fluorine, and veins in other deposits contained hydrothermal fluorite, although it was not ubiquitous. For the 495 samples from non-fluorspar mining districts (and excluding Jamestown), however, the median fluorine content was 990 ppm. This is above the crustal average but still relatively modest compared to the fluorspar deposits, and it indicates that the majority of the mineralizing systems in central Colorado did not deposit large amounts of fluorine. Nevertheless, the fluorine- and fluorite-rich mineral deposits could be used as guides for the evaluation and discovery of related but concealed porphyry and epithermal base- and precious-metal deposits. The Cenozoic geologic history of central Colorado included multiple periods during which fluorine-bearing rocks and mineral deposits were exposed, weathered, and eroded. This protracted history has released fluorine into soils and regoliths, and modern rainfall and snowmelt interact with these substrates to add fluorine to the hydrosphere. This study did not evaluate the fluorine contents of water or make any predictions about what areas might be major sources for dissolved fluorine. However, the abundant data that are available on fluorine in surface water and ground water can be coupled with the results of this study to provide additional insight into natural sources of fluorine in domestic drinking water.

Scientific Investigations Report↗
USGS2023

Using the gut microbiome to assess stocking efforts of the endangered Pallid Sturgeon, Scaphirhynchus albus

The endangered Pallid Sturgeon, Scaphirhynchus albus , has been actively managed to prevent population declines, including stocking of hatchery-raised fish. The gut microbiome plays an innate role in an organism’s absorption of nutrients by increasing nutrient availability and can provide new insights for Pallid Sturgeon management. In this study, the Pallid Sturgeon’s microbiome is dominated by the phyla Proteobacteria, Firmicutes, Actinobacteria and Fusobacteria. It was also determined that the gut bacterial diversity in hatchery-raised Pallid Sturgeon was not significantly different from wild Pallid Sturgeon, supporting that hatchery-raised Pallid Sturgeon are transitioning effectively to wild diets. There is also a high degree of intraspecific variation in the bacterial and eukaryotic sequences amongst individual Pallid Sturgeon microbiomes, suggesting the Pallid Sturgeon may be omnivorous. This study demonstrated that genetic markers may be used to effectively describe the dietary requirements for wild Pallid Sturgeon and provides the first genetic evidence that Pallid Sturgeons are effectively transitioning from hatchery-raised environments to the wild.

Missouri↗
USGS2014

Fathead minnow and bluegill sunfish life-stage responses to 17β-estradiol exposure in outdoor mesocosms

Developmental and reproductive effects of 17β-estradiol (E2) exposure on two generations of fathead minnows and one generation of bluegill sunfish were assessed. Fish were exposed to E2 for six continuous weeks in outdoor mesocosms simulating natural lake environments. First generation fish were exposed while sexually mature. Second generation fathead minnows were exposed either during early development, sexual maturity, or both stages. Multiple endpoints were measured to assess effects of E2 exposure on fecundity and fish health and development. Plasma vitellogenin concentrations were highly variable in all fish. Differences in egg production timing for both species indicate differences in fecundity between females exposed to E2 and controls. First generation fathead minnows exposed to E2 had lower body condition factors and reduced secondary sexual characteristic expression by males. Only a difference in relative liver weight was observed in second generation fathead minnows. First generation bluegill males exposed to E2 had significantly smaller testes compared to controls. Although fish response was highly variable, results indicate that exposure to E2 at environmentally relevant concentrations affect fathead minnow and bluegill sunfish health and development, which may have implications for the health and sustainability of fish populations. Furthermore, exposure timing and environmental factors affect fish response to E2 exposure.

Journal of the American Water Resources Associatio↗
USGS2014

Anthropogenic organic compounds in source water of select community water systems in the United States, 2002-10

Drinking water delivered by community water systems (CWSs) comes from one or both of two sources: surface water and groundwater. Source water is raw, untreated water used by CWSs and is usually treated before distribution to consumers. Beginning in 2002, the U.S. Geological Survey’s (USGS) National Water-Quality Assessment Program initiated Source Water-Quality Assessments (SWQAs) at select CWSs across the United States, primarily to characterize the occurrence of a large number of anthropogenic organic compounds that are predominantly unregulated by the U.S. Environmental Protection Agency. Source-water samples from CWSs were collected during 2002–10 from 20 surface-water sites (river intakes) and during 2002–09 from 448 groundwater sites (supply wells). River intakes were sampled approximately 16 times during a 1-year sampling period, and supply wells were sampled once. Samples were monitored for 265 anthropogenic organic compounds. An additional 3 herbicides and 16 herbicide degradates were monitored in samples collected from 8 river intakes and 118 supply wells in areas where these compounds likely have been used. Thirty-seven compounds have an established U.S. Environmental Protection Agency (EPA) Maximum Contaminant Level (MCL) for drinking water, 123 have USGS Health-Based Screening Levels (HBSLs), and 29 are included on the EPA Contaminant Candidate List 3. All compounds detected in source water were evaluated both with and without an assessment level and were grouped into 13 categories (hereafter termed as “use groups”) based on their primary use or source. The CWS sites were characterized in a national context using an extract of the EPA Safe Drinking Water Information System to develop spatially derived and system-specific ancillary data. Community water system information is contained in the EPA Public Supply Database, which includes 2,016 active river intakes and 112,099 active supply wells. Ancillary variables including population served, watershed size, land use, population density, and recharge were characterized for each of the watersheds for river intakes and contributing areas for supply wells. A total of 313 samples were collected from 20 river intakes. Between the years of 2002 through 2010, samples were collected approximately 16 times over the course of a year. Seventy-one compounds from 12 of the 13 use groups commonly occurred (detected in greater than or equal to 1 percent of samples using an assessment level of 0.05 microgram per liter or when a compound was detected in greater than or equal to 10 percent of samples without an assessment level) indicating a wide variety of sources and pathways to these rivers and highlighting the importance of source-water protection strategies. A total of 448 supply wells were sampled once during 2002–10 as part of 30 independent groundwater studies. About 15 CWS supply wells were sampled for each independent groundwater study. Twenty-eight compounds from 7 of the 13 use groups commonly occurred indicating a wide variety of sources and pathways exist for these compounds to reach these wells and highlighting the importance of wellhead protection strategies. About one-half the 265 compounds monitored (122) were detected in both surface water and groundwater samples. A more diverse suite of compounds were detected in surface water in comparison to groundwater. However, herbicides and herbicide degradates were the most frequent group of compounds detected in both surface water and groundwater. Sixty-five of the most commonly occurring compounds were detected in one or more samples from both surface water and groundwater. Human-health benchmarks (MCLs for regulated compounds and HBSLs for unregulated compounds) were available for more than one-half the compounds (160 of the 265) monitored in this study. Fifty-eight percent (41 of 71) of the commonly occurring compounds in surface water have a human-health benchmark to which concentrations can be compared; 19 have MCLs and 22 have HBSLs. Eighty-three percent (24 of 28) of the most commonly occurring compounds in groundwater have a human-health benchmark for which concentrations can be compared; 14 have MCLs and 10 have HBSLs. To put results from this study into context with the national distribution of river intakes and supply wells used by CWSs, sites were grouped into the respective national population of land-use quartiles. The increase in compound occurrence with increasing urban and agricultural land use in the watershed or contributing area was more evident for rivers than for supply wells. The increase in detection frequency of herbicides and herbicide degradates with increasing agricultural land use was more evident for rivers than for supply wells. The occurrence of solvents did not change substantially with increasing urban land use for rivers or supply wells. Basic co-occurrence analyses were completed with and without an assessment level. Considering all detections in surface water without an assessment level, approximately 86 percent of source-water samples contained 2 or more compounds, and 50 percent of samples contained at least 14 compounds. Considering all detections in groundwater without an assessment level, 50 percent of samples contained at least three compounds. For the most part, the compounds detected most frequently as individual compounds in the environment often composed the most frequent unique mixtures. Five of the 10 most frequently co-occurring unique mixtures in both surface water and groundwater were the same: atrazine and deethylatrazine; atrazine and chloroform; deethylatrazine and simazine; atrazine and simazine; and deethylatrazine, atrazine, and simazine. Because similar mixtures were identified in both surface water and groundwater without an assessment level, future studies could be directed toward better understanding the toxicological importance of these unique mixtures. Summed concentrations of herbicide degradates were compared to concentrations of the parent herbicides in surface-water and groundwater samples collected from 8 river intakes and 118 CWS wells, from which samples were analyzed for an additional 3 herbicides and 16 degradates. The toxicity to humans for many of these degradate products is largely unknown and thus points to the importance of monitoring these compounds (both the parent and degradate) in the environment. This study highlights the importance of anthropogenic organic compounds in source water of select CWSs in the United States by characterizing their occurrence in surface-water and groundwater samples. Compound concentrations and occurrence are summarized and evaluated in a human-health context, when possible. Additionally, compounds found to co-occur as mixtures for both surface water and groundwater highlight the significance of low-level compound co-occurrence.

Scientific Investigations Report↗
USGS1996

Assessment of saltwater intrusion in southern coastal Broward County, Florida

Of the counties in southeastern Florida, Broward County has experienced some of the most severe effects of saltwater intrusion into the surficial Biscayne aquifer because, before 1950, most public water-supply well fields in the county were constructed near the principal early population centers located less than 5 miles from the Atlantic Ocean. The construction of major regional drainage canals in the early 20th century caused a lowering of the water table and a gradual inland movement of the saltwater front toward the well fields. The U.S. Geological Survey began field investigations of saltwater intrusion in the Biscayne aquifer of southeastern Broward County in 1939. As part of the present study, the positions of the saltwater front in 1945, 1969, and 1993 were estimated using chloride concentrations of water samples collected between 1939 and 1994 from various monitoring and exploratory wells. The data indicate that, between 1945 and 1993, the saltwater front has moved as much as 0.5 mile inland in parts of the study area. The position and movement of the saltwater front were simulated numerically to help determine which of the various hydrologic factors and water-management features characterizing the coastal subsurface environment and its alteration by man are of significance in increasing or decreasing the degree of saltwater intrusion. Two representational methods were applied by the selection and use of appropriate model codes. The SHARP code simulates the position of the saltwater front as a sharp interface, which implies that no transition zone (a zone in which a gradational change between freshwater and saltwater occurs) separates freshwater and saltwater. The Subsurface Waste Injection Program (SWIP) code simulates a two-fluid, variable-density system using a convective-diffusion approach that includes a representation of the transition zone that occurs between the freshwater and saltwater bodies. The models were applied to: (1) approximately replicate predevelopment and current positions of the interface in the study area; and (2) study the relative importance of various factors affecting the interface position. The model analyses assumed a conceptual model of uniform easterly flow in the aquifer toward points of offshore discharge to tidewater. Measurements of water-table altitude and the depth to the interface in the study area exhibit an interrelation that differes substantially from the classical Ghyben-Herzberg relation. However, both model codes simulated water-table altitudes and interface positions that were generally consistent with the Ghyben-Herzberg relation but differed substantially from observed data. The simulate interface positions were inland of the known positions, and simulate water-table altitudes were higher than measured ones. The SHARP and SWIP simulations were in general agreement with each other when a low value of longitudinal dispersivity was specified in the SWIP simulation and also for higher values of longitudinal dispersivity when modified dispersion algorithms were used in SWIP that greatly reduced the simulated degree of vertical dispersion. Sensitivity analyses performed using the SHARP code indicated simulation results to be relatively insensitive to a substantial change in the specified slope of the base of the aquifer and moderately sensitive to a 150-percent change in net atmospheric recharge to the aquifer (rainfall minus evapotranspiration). Representing well-field pumping by the City of hallandale had only a minor, localized influence on the simulated regional interface position. Using various cross-sectional grid designs in applications of the SWIP code, near convergence of all lines of equal concentrations in the transition zone was achieved within a simulation time of 10 years. The simulated equilibrium interface location was sensitive to substantial spatial variations in the specified hydraulic conductivity values, but was relatively insensitive to seasonal varying

Florida↗
USGS2018

At-sea observations of marine birds and their habitats before and after the 2008 eruption of Kasatochi volcano, Alaska

Kasatochi volcano, an island volcano in the Aleutian chain, erupted on 7-8 August 2008. The resulting ash and pyroclastic flows blanketed the island, covering terrestrial habitats. We surveyed the marine environment surrounding Kasatochi Island in June and July of 2009 to document changes in abundance or distribution of nutrients, fish, and marine birds near the island when compared to patterns observed on earlier surveys conducted in 1996 and 2003. Analysis of SeaWiFS satellite imagery indicated that a large chlorophyll-a anomaly may have been the result of ash fertilization during the eruption. We found no evidence of continuing marine fertilization from terrestrial runoff 10 months after the eruption. At-sea surveys in June 2009 established that the most common species of seabirds at Kasatochi prior to the eruption, namely crested auklets (Aethia cristatella) and least auklets (Aethia pusilla) had returned to Kasatochi in relatively high numbers. Densities from more extensive surveys in July 2009 were compared with pre-eruption densities around Kasatochi and neighboring Ulak and Koniuji islands, but we found no evidence of an eruption effect. Crested and least auklet populations were not significantly reduced by the initial explosion and they returned to attempt breeding in 2009, even though nesting habitat had been rendered unusable. Maps of pre- and post-eruption seabird distribution anomalies indicated considerable variation, but we found no evidence that observed distributions were affected by the 2008 eruption. ?? 2010 Regents of the University of Colorado.

Arctic, Antarctic, and Alpine Research↗
USGS2007

The roles of physical habitat in reproduction and survival of pallid sturgeon and shovelnose sturgeon in the Lower Missouri River, progress 2005–06: Chapter D in Factors affecting the reproduction, recruitment, habitat, and population dynamics of pallid sturgeon and shovelnose sturgeon in the Missouri River

This report documents progress on three related components of habitat assessments in the Lower Missouri River during 2005–06. The habitat-use component links this research directly to sturgeon ecology research described in other chapters. The habitat availability and habitat dynamics assessments provide physical context for the ecological research. Results from 2005 to 2006 indicate that the methods developed to assess habitat use, quality, quantity, and dynamics are appropriate and sufficiently accurate to address critical questions about sturgeon habitat on the Lower Missouri River. Preliminary analysis of habitats occupied by adult female shovelnose sturgeon indicates that migrating sturgeon do not select for depth but seem to select for lower than reach-averaged velocities and higher than reach-averaged velocity gradients. Data collected to compile, calibrate, and validate multidimensional hydraulic models in probable spawning reaches appear to be sufficient to support the modeling objectives. Monitoring of selected channel cross sections and long profiles multiple times during the year showed little change at the upstreammost reach over the range of flows measured during 2006, likely because of channel stability associated with an armored bed. Geomorphic changes documented at monitoring cross sections increased with distance downstream. Hydroacoustic substrate-class parameters documented systematic changes with discharge and with hydraulic environment across the channel. Similarly, bed velocity varied predictably with discharge and hydraulic environment, indicating its potential as an indicator of bedload sediment transport. Longitudinal profiles showed substantial downstream movement of dunes over the monitored discharges, as well as substantial within-year variability in dune size. Observations of geomorphic change during the moderate flow range of 2006 support the hypothesis that the magnitude of flow modifications under consideration on the Lower Missouri River will be sufficient to transport sediment and potentially modify spawning habitats.

Lower Missouri River↗
USGS2021

Biotic and abiotic determinants of finescale dace distribution at the southern edge of their range

Aim The factors that set range limits for animal populations can inform management plans aimed at maintaining regional biodiversity. We examine abiotic and biotic drivers of the distribution of finescale dace ( Chrosomus neogaeus ) in two Great Plains basins to identify limiting factors for a threatened freshwater fish population at the edge of their range. Location Great Plains, Nebraska, South Dakota and Wyoming, USA. Methods We investigated abiotic and biotic factors influencing the contemporary distribution of finescale dace in the Belle Fourche and Niobrara River basins with Random Forests classification models using fish surveys from multiple agencies spanning 2008–2019 and GIS-derived environmental data. Results In both basins, finescale dace occurrence exhibited a nonlinear response to mean August water temperature. Abiotic covariates, including streamflow, water temperature and channel slope, were important limiting factors in the final model fit with Belle Fourche River basin surveys ( n = 131). In contrast, a biotic covariate, native minnow richness, was the most important predictor of finescale dace occurrence in the Niobrara River basin model ( n = 27). In the Niobrara River, native minnow richness was lower at sites with non-native northern pike ( Esox lucius ). Main conclusions Basin-specific analyses revealed context dependencies for species–environment relationships, which can inform targeted restoration actions. Similar relationships between water temperature and finescale dace occurrence across both basins suggest summer thermal habitat as a regional limiting factor. The importance of biotic interactions in the Niobrara River highlights an emergent threat from invasive predators to a distinct assemblage of native prairie fishes.

Nebraska, South Dakota, Wyoming↗
USGS2007

Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

Geochemical Transactions↗
USGS2018

Non‐linear effect of sea ice: Spectacled Eider survival declines at both extremes of the ice spectrum

Understanding the relationship between environmental factors and vital rates is an important step in predicting a species’ response to environmental change. Species associated with sea ice are of particular concern because sea ice is projected to decrease rapidly in polar environments with continued levels of greenhouse gas emissions. The relationship between sea ice and the vital rates of the Spectacled Eider, a threatened species that breeds in Alaska and Russia and winters in the Bering Sea, appears to be complex. While severe ice can impede foraging for benthic prey, ice also suppresses wave action and provides a platform on which eiders roost, thereby reducing thermoregulation costs. We analyzed a 23‐year mark‐recapture dataset for Spectacled Eiders nesting on Kigigak Island in western Alaska, and tested survival models containing different ice and weather‐related covariates. We found that much of the variation in eider survival could be explained by the number of days per year with >95% sea ice concentration at the Bering Sea core wintering area. Furthermore, the data supported a quadratic relationship with sea ice rather than a linear one, indicating that intermediate sea ice concentrations were optimal for survival. We then used matrix population models to project population trajectories using General Circulation Model (GCM) outputs of daily sea ice cover. GCMs projected reduced sea ice at the wintering area by year 2100 under a moderated emissions scenario (RCP 4.5) and nearly ice‐free conditions under an unabated emissions scenario (RCP 8.5). Under RCP 4.5, stochastic models projected an increase in population size until 2069 coincident with moderate ice conditions, followed by a decline in population size as ice conditions shifted from intermediate to mostly ice‐free. Under RCP 8.5, eider abundance increased until 2040 and then decreased to near extirpation toward the end of the century as the Bering Sea became ice‐free. Considerable uncertainty around parameter estimates for survival in years with minimal sea ice contributed to variation in stochastic projections of future population size, and this uncertainty could be reduced with additional survival data from low‐ice winters.

Alaska↗
USGS2013

Ecosystem services: developing sustainable management paradigms based on wetland functions and processes

In the late nineteenth century and twentieth century, there was considerable interest and activity to develop the United States for agricultural, mining, and many other purposes to improve the quality of human life standards and prosperity. Most of the work to support this development was focused along disciplinary lines with little attention focused on ecosystem service trade-offs or synergisms, especially those that transcended boundaries of scientific disciplines and specific interest groups. Concurrently, human population size has increased substantially and its use of ecosystem services has increased more than five-fold over just the past century. Consequently, the contemporary landscape has been highly modified for human use, leaving behind a fragmented landscape where basic ecosystem functions and processes have been broadly altered. Over this period, climate change also interacted with other anthropogenic effects, resulting in modern environmental problems having a complexity that is without historical precedent. The challenge before the scientific community is to develop new science paradigms that integrate relevant scientific disciplines to properly frame and evaluate modern environmental problems in a systems-type approach to better inform the decision-making process. Wetland science is a relatively new discipline that grew out of the conservation movement of the early twentieth century. In the United States, most of the conservation attention in the earlier days was on wildlife, but a growing human awareness of the importance of the environment led to the passage of the National Environmental Policy Act in 1969. Concurrently, there was a broadening interest in conservation science, and the scientific study of wetlands gradually gained acceptance as a scientific discipline. Pioneering wetland scientists became formally organized when they formed The Society of Wetland Scientists in 1980 and established a publication outlet to share wetland research findings. In comparison to older and more traditional scientific disciplines, the wetland sciences may be better equipped to tackle today’s complex problems. Since its emergence as a scientific discipline, the study of wetlands has frequently required interdisciplinary and integrated approaches. This interdisciplinary/integrated approach is largely the result of the fact that wetlands cannot be studied in isolation of upland areas that contribute surface and subsurface water, solutes, sediments, and nutrients into wetland basins. However, challenges still remain in thoroughly integrating the wetland sciences with scientific disciplines involved in upland studies, especially those involved with agriculture, development, and other land-conversion activities that influence wetland hydrology, chemistry, and sedimentation. One way to facilitate this integration is to develop an understanding of how human activities affect wetland ecosystem services, especially the trade-offs and synergisms that occur when land-use changes are made. Used in this context, an understanding of the real costs of managing for a particular ecosystem service or groups of services can be determined and quantified in terms of reduced delivery of other services and in overall sustainability of the wetland and the landscapes that support them. In this chapter, we discuss some of the more salient aspects of a few common wetland types to give the reader some background on the diversity of functions that wetlands perform and the specific ecosystem services they provide to society. Wetlands are among the most complex ecosystems on the planet, and it is often difficult to communicate to a diverse public all of the positive services wetlands provide to mankind. Our goal is to help the reader develop an understanding that management options can be approached as societal choices where decisions can be made within a spatial and temporal context to identify trade-offs, synergies, and effects on long-term sustainability of wetland ecosystems. This will be especially relevant as we move into alternate climate futures where our portfolio of management options for mitigating damage to ecosystem function or detrimental cascading effects must be diverse and effective.

Book chapter↗
USGS1996

Holocene paleoenvironments of Northeast Iowa

This paper presents the biotic, sedimentary, geomorphic, and climatic history of the upper part of the Roberts Creek Basin, northeastern Iowa for the late—glacial and Holocene, and compares these records with a C—O isotopic sequence from Coldwater Cave, 60 km northwest of Roberts Creek. The biotic record (pollen, vascular plant and bryophyte macrofossils, and insects) is preserved in floodplain alluvium that underlies three constructional surfaces separated by low scarps. Each surface is underlain by a lithologically and temporally distinct alluvial fill. The highest surface is underlain by the Gunder Member of the Deforest Formation, dating from 11 000 to 4000 yr BP; beneath the intermediate level is the Roberts Creek Member, dating from 4000 to 400 yr BP; and the lowest level is underlain by the Camp Creek Member, deposited during the last 380 yr. Pollen and plant macrofossils in the alluvial fill show that a typical late—glacial spruce forest was replaced by Quercus and Ulmus in the early Holocene. This early—to—middle Holocene forest became dominated by mesic elements such as Acer saccharum, Tilia americana, Ostrya virginiana, and Carpinus caroliniana as late as 5500 yr BP; in contrast, the closest sites to the west and north were at their warmest and driest and were covered by prairie vegetation between 6500 and 5500 yr BP. After 5500 yr BP, the forest in the Roberts Creek area was replaced by prairie, as indicated by a rich assemblage of plant macrofossils, although only Ambrosia and Poaceae became abundant in the pollen record. The return of Quercus ≈ 3000 BP (while nonarboreal pollen percentages remained relatively high) indicates that oak savanna prevailed with little change until settlement time. The bryophyte assemblages strongly support the vascular plant record. Rich fen species characteristic of boreal habitats occur only in the late—glacial. They are replaced by a number of deciduous—forest elements when early—to—middle Holocene forests were present, but mosses of forest habitats completely disappear when prairie became dominant. A few deciduous—forest taxa return during the late—Holocene, when oak savanna prevailed. The C—O isotopic record from stalagmite s in Coldwater Cave indicates a relatively stable environment from ≈ 8000 to 5100 yr BP, when the δ 13 C values indicate a change in vegetation dominated by C 3 (predominantly forest) to C 4 (predominantly prairie) plants. About 4900 yr BP, the rise in 18 O values indicates a temperature increase of ≈ 1.5 ° C. The fact that the vegetational change suggested by the δ 13 C values preceded the temperature increase suggests that fire may have been an important factor in converting forest to prairie. Abundant charred seeds and other plant material at Roberts Creek 4830 yr BP support this hypothesis. The 18 O values remain constant from ≈ 5100 to ≈ 3000 yr BP, but the δ 13 C values gradually rise, indicating that soil formed under forest takes at least 2000 yr for its carbon to reach equilibrium after replacement by prairie vegetation. The return of oak to form savanna is reflected in the gradual decline of δ 13 C values in the last 3000 yr BP; O isotopic values drop sharply by ≈ 1 ° C ≈ 2800 yr BP and then were relatively stable. In contrast to the vegetational and isotopic records, the insect assemblages suggest little change in the local environments throughout most of the Holocene. All of the beetle taxa presently occur in eastern Iowa. The relative stability through the Holocene indicates that both open grassland and riparian woodland elements were present throughout. Settlement, land clearing, and land cultivation by EuroAmericans in the region caused rapid erosion of the upland landscape, the deposition of 1—2 m of sediment across the floodplain, a replacement of the native vegetation with ruderal species, a decimation of the native insect fauna, and a degradation of water quality in the stream. These changes in the landscape, vegetation, and insect faunas are as striking as those associated with glacial—interglacial transitions. The timing and direction of changes in the vegetation at Roberts Creek generally correlate well with the carbon and oxygen isotopic record in speleothems at nearby Coldwater Cave and indicate that climate was the main forcing function. However, the contrast between the vegetational change and the stability of the beetle population suggests that climatic changes were subtle. We hypothesize that the factors involved in the Holocene changes were seasonal changes in temperature and precipitation that may not have resulted in much mean annual change. Such changes may have affected the vegetation more than the insect fauna.

Iowa↗
USGS2023

Informing management of recovering predators and their prey with ecological diffusion models

The reintroduction and recovery of predators can be ecologically beneficial as well as socially and economically controversial. However, the growth and expansion of predator populations, and thus their ecological, social, and economic impacts, are not static but rather they vary in space and time. We propose a spatiotemporal statistical modeling framework based on ecological diffusion to better inform the ecology and management of recovering predators and their prey. We demonstrate its utility by applying it to a recovering sea otter ( Enhydra lutris ) population in Southeast Alaska, where sea otters were reintroduced in the late 1960s and have exhibited unprecedented population growth. Estimated parameters yield inferences about movement and population ecology, and our approach provides useful derived quantities, such as local abundance and carrying capacity as well as a quantity we term the equilibrium differential. We used our model to examine how density dependence and carrying capacity of sea otters vary spatially across a region. The diffusion modeling approach we present can be generalized for use in other instances of (re)colonization across taxa to inform management and conservation efforts.

Alaska↗
USGS2025

Implications of physics-based M9 ground motions on liquefaction-induced damage in the Cascadia Subduction Zone: Looking forward and backward

Given the likelihood of future M9 Cascadia Subduction Zone (CSZ) earthquakes, various estimates of the resulting, regional ground motions have been made, including a suite of 30 physics-based simulations that reflect key modeling uncertainties. However, because the last CSZ interface rupture occurred in 1700 CE, the shaking expected in such an event is especially uncertain, as are the impacts to the built and living environments. Like other coseismic impacts, soil liquefaction poses a significant threat and must be considered by any scenario study used to inform planning and response, or to focus mitigation resources. Liquefaction is also notable for its potential to “ground truth” ground-motion estimates, given that its presence or absence in the geologic record can provide constraint on the intensities of shaking in past events. It is thus an important phenomenon looking both forward and backward. Accordingly, using recent physics-based simulations, this study (1) predicts liquefaction in M9 CSZ ruptures at 400 locations in Oregon, Washington, and British Columbia (BC) using an array of cone-penetration-test based models and (2) uses paleoliquefaction evidence at ten sites spanning from Southern Oregon to Vancouver, BC to constrain possible ground-motion intensities experienced in the 1700 CE earthquake. The forward predictions indicate that liquefaction in M9 events could be pervasive in the region and affect numerous population hubs, with the potential for damage across hundreds of square kilometers. The backward analyses suggest that 1700 CE ground-motion intensities may have been less than expected from M9 simulations in some northern portions of the CSZ (e.g. Seattle), given the paucity of 1700 CE liquefaction evidence in these areas. Ultimately, further discovery and analysis of CSZ paleoliquefaction, or lack thereof, will confirm or modify this possibility and the conclusions drawn herein.

Oregon, Washington↗
USGS2011

Patterns of coral disease across the Hawaiian Archipelago: Relating disease to environment

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing a negative association, but no significant explanatory power was offered for PorTLS.

Hawaii↗
USGS1980

Toxicity of five forest insecticides to cutthroat trout and two species of aquatic invertebrates

The Northern Rocky Mountain region has had scattered infestation of the western spruce budworm Christoneura occidentalis since the early 1900's (U.S. DEPARTMENT OF AGRICULTURE (USDA) 1976b). On the basis of aerial surveys in 1975, TUNNOCK et al. (1976), estimated that budworm defoliation occurred on 2,278,804 acres of six National Forests in Montana. Since the use of DDT was banned in 1972, there has been a need to develop alternative insecticides with the efficacy of DDT but without its environmental risk. These insecticides must be effective in controlling the budworm, but should not persist in the environment or be toxic to other organisms. The organophosphate and carbamate insecticides are relatively nonpersistent and generally present only a moderate hazard to fish when applied according to label recommendations. The USDA Forest Service has been investigating the effectiveness of these two classes of insecticides against the budworm, and the Columbia National Fisheries Research Laboratory of the U.S. Fish and Wildlife Service has been cooperating with the Forest Service conducted pilot control projects in eastern Montana in 1975 and 1976 to determine the efficacy and environmental impact of acephate, carbaryl, and trichlorfon in controlling the western budworm (USDA 1976 b). In 1975, a similar type project was carried out in Maine with aminocarb, fenitrothion, and trichlorfon (USDA 1976 a). Acephate, fenitrothion, and trichlorfon (organophosphate insecticides) and aminocarb and carbaryl (carbamate insecticides) were selected for toxicity tests against cutthroat trout ( Salmo clarki ), a stonefly ( Pteronarcella badia ), and a freshwater amphipod ( Gammarus pseudolimnaeus ) edemic in streams of the northern Rocky Mountains. Populations of cutthroat trout inhabit lakes and streams in the Rocky Mountains which include some of the most pristine habitat and fisheries in North America. Pteronarcella and Gammarus provide forage for cutthroat trout and feed on decaying vegetation in riffle areas in streams and rivers. Stonefly naiads and amphipods were selected as test organisms because of their importance as trout food and their wide distribution in mountain stream communities. We determined the effect of various water types representing different biogeographical areas in the Intermountain West on the toxicity of these five forest insecticides.

Bulletin of Environmental Contamination and Toxico↗
USGS2006

An introduced predator alters Aleutian Island plant communities by thwarting nutrient subsidies

The ramifying effects of top predators on food webs traditionally have been studied within the framework of trophic cascades. Trophic cascades are compelling because they embody powerful indirect effects of predators on primary production. Although less studied, indirect effects of predators may occur via routes that are not exclusively trophic. We quantified how the introduction of foxes onto the Aleutian Islands transformed plant communities by reducing abundant seabird populations, thereby disrupting nutrient subsidies vectored by seabirds from sea to land. We compared soil and plant fertility, plant biomass and community composition, and stable isotopes of nitrogen in soil, plants, and other organisms on nine fox-infested and nine historically fox-free islands across the Aleutians. Additionally, we experimentally augmented nutrients on a fox-infested island to test whether differences in plant productivity and composition between fox-infested and fox-free islands could have arisen from differences in nutrient inputs between island types. Islands with historical fox infestations had soils low in phosphorus and nitrogen and plants low in tissue nitrogen. Soils, plants, slugs, flies, spiders, and bird droppings on these islands had low d15N values indicating that these organisms obtained nitrogen from internally derived sources. In contrast, soils, plants, and higher trophic level organisms on fox-free islands had elevated d15N signatures indicating that they utilized nutrients derived from the marine environment. Furthermore, soil phosphorus (but not nitrogen) and plant tissue nitrogen were higher on fox-free than fox-infested islands. Nutrient subsidized fox-free islands supported lush, high biomass plant communities dominated by graminoids. Fox-infested islands were less graminoid dominated and had higher cover and biomass of low-lying forbs and dwarf shrubs. While d15N profiles of soils and plants and graminoid biomass varied with island size and distance from shore, after accounting for these effects differences between fox-infested and fox-free islands still existed. Fertilization over four years caused a 24-fold increase in graminoid biomass and a shift toward a more graminoid dominated plant community typical of fox-free islands. These results indicate that apex predators can influence plant productivity and composition through complex interaction web pathways involving both top-down forcing and bottom-up nutrient exchanges across systems. ?? 2006 by the Ecological Society of America.

Ecological Monographs↗