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At least 433 records · Page 24Linked to original sources
USGS2023

Selenium hazards in the Salton Sea environment—Summary of current knowledge to inform future wetland management

Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural, and energy production processes. The mobilization of selenium from shales through agricultural irrigation has been recognized since the 1930s; however, discovery of deformities in birds and other wildlife using agricultural habitats during the 1980s spurred studies to determine the extent and effects of the contamination. Through these early studies, researchers determined that biota in the Salton Sea drainage basin was at risk from legacy selenium contamination in the Colorado River watershed. The Salton Sea and its surrounding managed and unmanaged wetlands provide vital inland habitat and trophic support for diverse assemblages of resident and migratory wildlife, and understanding regional selenium hazards for these trust species is a priority for many Federal and State agencies. The modern Salton Sea is a shallow, landlocked saline lake in Riverside and Imperial Counties (not shown) of California that is sustained by irrigation return and perennial river inflow. Changes in water transfer agreements under the 2003 Quantification Settlement Agreement (QSA) have resulted in reduced irrigation flow, declining lake levels, and the evolution of unmanaged wetlands in areas where drains and rivers no longer reach the Salton Sea. These wetlands provide additional habitat for some species of concern, but their potential to increase selenium hazards for trust species is largely unknown. From the 1980s to 2020, efforts to document selenium contamination and effects throughout the region have resulted in a considerable amount of selenium data from the Salton Sea and its surrounding drainage basin; however, no long-term (greater than 20 years), consistent sampling program has been established, and all data have been collected by different entities using a variety of protocols and analytical techniques. This lack of coordination has been previously documented in regional management plans and has led to difficulty in reliably assessing selenium hazards in the Salton Sea environment. This report provides a summary of the available disparate selenium information collected from water, sediment, and biota in the Salton Sea region since the 1980s and to identify data gaps that need to be filled to understand the potential effects of selenium on species of concern, including federally endangered desert pupfish ( Cyprinodon macularius ) and Yuma Ridgway’s Rail ( Rallus obsoletus yumanensis; formerly Yuma Clapper Rail, Rallus longirostris yumanensis ). Available data from the Salton Sea drainage basin show that water from the Colorado River has the lowest selenium concentration of all surface water sources. All other surface water flowing into the Salton Sea has elevated selenium concentrations due to evaporation and evapotranspiration that occurs in agricultural fields and associated water delivery infrastructure or leaching of selenium from irrigated farmland soils. The Salton Sea has lower selenium concentrations because of various biogeochemical processes that recycle selenium into the sediment or volatilize it to the atmosphere; however, these mechanisms are not well defined, and it is not clear if selenium cycling will change in response to possible changes in the oxidation state of the Salton Sea bottom waters as water levels decline. Agricultural drains have the highest average selenium concentrations, but few drains have been sampled since changes in irrigation practices have occurred (due to the 2003 QSA). Groundwater selenium concentrations are variable; some wells south of the Salton Sea have selenium concentrations as high as 300 micrograms per liter (µg/L), whereas selenium concentrations are below detection in other wells. Groundwater and surface-water geothermal discharge zones around the margins of the Salton Sea and in unmanaged wetlands have not been studied in detail, and published selenium measurements are not available for these surface features. Selenium concentrations in the sediment of the Salton Sea drainage basin are highest in wetland particulate organic matter and the Salton Sea lakebed, indicating that removal of selenium from the water to the sediment has been a primary mechanism for keeping selenium concentrations low in the water column. Sediment selenium concentrations in wetlands are lower than in the Salton Sea but higher than inflowing drains and rivers, indicating the lentic wetland sites also may be important sinks for selenium because of biogeochemical processes. Sediment selenium data have not been collected in agricultural drains since changes in irrigation practices occurred (due to the 2003 QSA), and it is unknown if selenium sequestration from the water column has changed in these systems. We divided biological data into broad taxonomic categories, including primary producers, invertebrates, herpetofauna, mammals, fishes, and birds to facilitate evaluation of selenium concentrations and spatiotemporal trends observed in the Salton Sea. Overall, selenium concentrations were substantially greater in algae samples compared to all vascular plant samples combined. Median selenium concentrations in several invertebrate taxa (Chironomidae, Formicidae, Corixidae, Corbiculidae and Nereididae, and Decapoda) exceeded the maximum suggested dietary threshold of 3.0–4.0 micrograms per gram (µg/g) dry weight (dw) for predators consuming invertebrates in aquatic food webs. The greatest number of samples were collected from fish, and selenium distributions among species and locations showed that the range for most samples was lower than the U.S. Environmental Protection Agency selenium criterion for aquatic life (8.5 µg/g dw whole body, 11.3 µg/g dw fillets). The median selenium concentrations for whole body fish were below the selenium criterion in most locations, except for bairdiella ( Bairdiella icistia ) from the Salton Sea and irrigation drains, a few individual tilapia spp. (family Cichlidae, including genera Tilapia, Oreochromis , and their hybrids) from the river and river outlets, and several western mosquitofish ( Gambusia affinis ) and sailfin molly ( Poecilia latipinna ) from irrigation drain outlets. For avian samples combined among years and locations, median selenium concentrations in livers from all families except waders and Ibis (family Threskiornithidae) were higher than levels expected to cause selenium toxicosis (10–20 µg/g dw), and all median egg concentrations were above or near 6.0 μg/g dw, which is a conservative threshold value for reproductive impairment. Most knowledge gaps we identified for water, sediment, and biota were interrelated, and the use of integrated approaches to address knowledge gaps can provide greater insight into the drivers behind selenium hazards. Integrated water, sediment, and biota studies could help identify cost-effective management solutions that serve multiple purposes. A comprehensive analysis of the hydrology, biogeochemistry, and food-web processes in wetlands and other habitats can inform predictive models to identify drivers of selenium bioavailability, uptake from the environment and subsequent trophic transfer, ultimately forming the basis for experimental habitat management manipulations to minimize selenium hazards to wildlife. Furthermore, a comprehensive, long-term sampling and analytical laboratory plan would enable comparison of data among different entities that are sampling at the Salton Sea. Such efforts are well suited to help fill knowledge gaps that preclude understanding of selenium hazards and future management options for biota using Salton Sea habitats, including newly formed wetlands throughout the region. All data compiled for this report are available in two U.S. Geological Survey data releases: Groover and others (2022) for water and sediment samples and De La Cruz and others (2022) for biological samples. The data releases include all publicly available data for selenium concentrations in water, sediment, and biological samples collected in and around the Salton Sea, including the Coachella and Imperial Valleys. The data releases also include previously unpublished data.

California↗
USGS2016

A network model framework for prioritizing wetland conservation in the Great Plains

Context Playa wetlands are the primary habitat for numerous wetland-dependent species in the Southern Great Plains of North America. Plant and wildlife populations that inhabit these wetlands are reciprocally linked through the dispersal of individuals, propagules and ultimately genes among local populations. Objective To develop and implement a framework using network models for conceptualizing, representing and analyzing potential biological flows among 48,981 spatially discrete playa wetlands in the Southern Great Plains. Methods We examined changes in connectivity patterns and assessed the relative importance of wetlands to maintaining these patterns by targeting wetlands for removal based on network centrality metrics weighted by estimates of habitat quality and probability of inundation. Results We identified several distinct, broad-scale sub networks and phase transitions among playa wetlands in the Southern Plains. In particular, for organisms that can disperse > 2 km a dense and expansive wetland sub network emerges in the Southern High Plains. This network was characterized by localized, densely connected wetland clusters at link distances ( h ) >2 km but <5 km and was most sensitive to changes in wetland availability ( p ) and configuration when h = 4 km, and p = 0.2–0.4. It transitioned to a single, large connected wetland system at broader spatial scales even when the proportion of inundated wetland was relatively low ( p = 0.2). Conclusions Our findings suggest that redundancy in the potential for broad and fine-scale movements insulates this system from damage and facilitates system-wide connectivity among populations with different dispersal capacities.

New Mexico, Texas↗
USGS2015

Wildlife, urban inputs, and landscape configuration are responsible for degraded swimming water quality at an embayed beach

Jeorse Park Beach, on southern Lake Michigan, experiences frequent closures due to high Escherichia coli ( E. coli ) levels since regular monitoring was implemented in 2005. During the summer of 2010, contaminant source tracking techniques, such as the conventional microbial and physical surveys and hydrodynamic models, were used to determine the reasons for poor water quality at Jeorse Park. Fecal indicator bacteria ( E. coli , enterococci) were high throughout the season, with densities ranging from 12&ndash;2419 (culturable E. coli ) and 1&ndash;2550 and < 1&ndash;5831 (culturable and qPCR enterococci, respectively). Genetic markers for human ( Bacteroides HF183) and gull ( Catellicoccus marimammalium ) fecal contamination were found in 15% and 37% of the samples indicating multiple sources contributing to poor water quality. Nesting colonies of double-crested cormorants ( Phalacrocorax auritus ) have steadily increased since 2005, coinciding with high E. coli levels. A hydrodynamic model indicated that limited circulation allows bacteria entering the embayed area to be retained in nearshore areas; and bacterial resuspension from sand and stranded beach wrack during storm events compounds the problem. The integration of hydrodynamics, expanded use of chemical and biological markers, as well as more complex statistical multivariate techniques can improve microbial source tracking, informing management actions to improve recreational water quality. Alterations to embayed structures to improve circulation and reduce nuisance algae as well as growing native plants to retain sand to improve beach morphometry are among some of the restoration strategies under consideration in ongoing multi-agency collaborations.

Indiana↗
USGS2009

Germination and establishment of the native plains cottonwood ( Populus deltoides Marshall subsp. monilifera ) and the exotic Russian-olive ( Elaeagnus angustifolia L.)

Russian-olive ( Elaeagnus angustifolia ) is a small Eurasian tree that has escaped from cultivation and become naturalized, primarily along watercourses throughout the western United States. We examined germination and establishment of Russian-olive and plains cottonwood ( Populus deltoides ), the principal native riparian tree of the Great Plains, under a range of experimental moisture and light conditions. The fewest seedings established under the driest conditions; seedling biomass was predictably lower in the shade; root-to-shoot ratios were higher for cottonwood, higher in the sun, and higher under drier conditions. Several interactions were also significant. The timing of germination and mortality varied between plains cottonwood and Russian-olive: cottonwood germinated in mid-June in all treatments in a single pulse with subsequent mortality; the timing and amount of Russian-olive germination differed substantially across treatments with little net mortality. Differences in life-history traits of these species, including seed size, viability, and dispersal, help explain treatment differences. Russian-olive will likely remain an important component of riparian communities along both unregulated and regulated western rivers because it succeeds under conditions optimal for cottonwood establishment and under many conditions unfavorable for cottonwood. Furthermore, many western states still encourage planting of Russian-olive, and control techniques tend to be labor-intensive and expensive .

Conservation Biology↗
USGS2009

Disturbance alters local-regional richness relationships in appalachian forests

Whether biological diversity within communities is limited by local interactions or regional species pools remains an important question in ecology. In this paper, we investigate how an experimentally applied tree-harvesting disturbance gradient influenced local-regional richness relationships. Plant species richness was measured at three spatial scales (2 ha = regional; 576 m 2 and 1 m 2 = local) on three occasions (one year pre-disturbance, one year post-disturbance, and 10 years post-disturbance) across five disturbance treatments (uncut control through clearcut) replicated throughout the southern Appalachian Mountains, USA. We investigated whether species richness in 576-m 2 plots and 1-m 2 subplots depended on species richness in 2-ha experimental units and whether this relationship changed through time before and after canopy disturbance. We found that, before disturbance, the relationship between local and regional richness was weak or nonexistent. One year after disturbance local richness was a positive function of regional richness, because local sites were colonized from the regional species pool. Ten years after disturbance, the positive relationship persisted, but the slope had decreased by half. These results suggest that disturbance can set the stage for strong influences of regional species pools on local community assembly in temperate forests. However, as time since disturbance increases, local controls on community assembly decouple the relationships between regional and local diversity. ?? 2009 by the Ecological Society of America.

Ecology↗
USGS2021

Directional selection shifts trait distributions of planted species in dryland restoration

The match between species trait values and local abiotic filters can restrict community membership. An often-implicit assumption of this relationship is that abiotic filters select for a single locally optimal strategy, though difficulty in isolating effects of the abiotic environment from those of dispersal limitation and biotic interactions has resulted in few empirical tests of this assumption. Similar constraints have made it difficult to assess whether the type and intensity of abiotic filters shift along gradients of environmental harshness, as predicted by the stress-dominance hypothesis. We planted 9,216 plants of 29 perennial grass and forb species that had a range of functional trait values and were assigned to a warm, intermediate or cool temperature tolerance pool across eight sites on the Colorado Plateau. We compared the distributions of traits of surviving individuals to null distributions to evaluate whether there were shifts in trait means and variation. Borrowing from phenotypic selection concepts in evolutionary biology, we assessed support for stabilizing, directional and disruptive abiotic filtering of trait distributions and whether these types of filtering varied with initial species pool. Functional composition was significantly different from null distributions for nearly all traits at all sites, with trait variation more restricted in harsher abiotic conditions, supporting the stress-dominance hypothesis. Contrary to expectations, we primarily found evidence for directional selection, which increased in frequency in warm species pools while disruptive selection was found more often in cool and intermediate species pools. Synthesis . This study provides a controlled experimental approach to test the effect of the abiotic environment on plant trait filtering. We found that opportunistic strategies allowing for rapid water acquisition during favourable periods improved survival at warmer sites. Species with these strategies may be expected to benefit from increasing aridity and may be selected for active management efforts. More generally, the prevalence of directional selection may have important implications for dynamic vegetation models that rely on trait distributions for translating environmental variation into ecosystem processes.

Journal of Ecology↗
USGS1972

Physical, chemical, and biological aspects of the Duwamish River Estuary, King County, Washington, 1963-67

This report describes the significant results to 1967 of a comprehensive study that began in 1963 to evaluate what changes take place in an estuary as the loads .of raw and partially treated industrial and municipal wastes are replaced by effluent from a secondary treatment plant. The study area is the Duwamish River estuary, about 18.3 river kilometers long. At mean sea level the estuary has a water-surface area of about 1 square mile and a mean width of 440 feet. At the lowest and highest recorded tides, the volume of the estuary is about 205 and 592 million cubic feet, respectively. The estuary is well stratified (salt-wedge type) at fresh-water inflows greater than 1,000 cfs (cubic feet per second), but when inflow rates are less than 1,000 cfs the lower 5.6 kilometers of the estuary grades into the partly mixed type. The crosschannel salinity distribution is uniform for a given location and depth. Salinity migration is controlled by tides and fresh-water inflow. At fresh-water inflow rates greater than 1,000 cfs, water in the upper 8.4 kilometers of the estuary is always fresh regardless of tide. At inflow rates less than 600 cfs and tide heights greater than 10 feet; some salinity has been detected 16.1 kilometers above the mouth of the estuary. Studies using a fluorescent dye show that virtually no downward mixing into the salt wedge occurs; soluble pollutants introduced at the upper end of the estuary stay in the surface layer (5-15 ft thick). On the basis of dye studies when fresh-water inflow is less than 400 cfs, it is estimated that less than 10 percent of a pollutant will remain in the estuary a minimum of 7 days. Longitudinal dispersion coefficients for the surface layer have been determined to be on the order of 100-400 square feet per second. Four water-quality stations automatically monitor DO (dissolved oxygen), water temperature, pH, and specific conductance; at one station solar radiation also is measured. DO concentration in the surface layer decreases almost linearly in a downstream direction. Minimum DO concentration in the surface layer is usually greater than 4 rag/1 (milligrams per liter). The smallest DO values are consistently recorded in the bottom layer at the station 7.7 kilometers above the mouth; monthly means of less than 3 mg/1 of DO have occurred at this point. Manual sampling shows that the DO sag in the bottom layer oscillates between 7.7 and 10.4 kilometers above the mouth of the estuary. Multiple-regression analysis shows that the surface DO content can be estimated from the fresh-water inflow and water temperature. Tidal exchange and fresh-water inflow indirectly control the bottom DO content. Information available from previous studies failed to indicate a progressive decrease in DO content during the period 1949-56, but data from the present study suggest a slight general decrease in the annual minimum DO concentrations in both the upper and lower layers. Average nitrate concentration in fresh water at station 16.2 has increased progressively since 1964, by amounts greater than those which can be attributed to the Renton Treatment Plant, 4.3 kilometers upstream from station 16.2. The BOD (biochemical oxygen demand) in both surface and bottom layers is generally less than 4 rag/1 of oxygen, but values greater than 6 rag/1 have been measured during a period of phytoplankton bloom. Phytoplankton blooms can occur during periods of minimum tidal exchange and fresh-water inflows of less than 300 cfs if solar radiation and water temperature are optimum. Nutrients (nitrogen and phosphorus compounds) do not control the occurrence of a bloom, because sufficient quantities of these nutrients are always present. Nutrients in the treated effluent may increase the biomass of the bloom. Trace-element studies have not defined any role that these elements may play in algal growth. The inflowing fresh water contains principally calcium and bicarbonate and has a dissolved-solids content ra

Water Supply Paper↗
USGS2019

Induced biological soil crust controls on wind erodibility and dust (PM10) emissions

Inducing biological soil crust (biocrust) development is an appealing approach for dust mitigation in drylands due to the resistance biocrusts can provide against erosion. Using a portable device, we evaluated dust emissions from surfaces either inoculated with biocrust, amended with a plant‐based soil stabilizer, or both at varying wind friction velocities. Four months after application, emissions from all treatments were either indistinguishable from or greater than controls, despite evidence of biocrust establishment. All treatments had greater surface roughness and showed more evidence of entrapment of windblown sediment than controls, factors which may have been partially responsible for elevated emissions. There was a synergistic effect of inoculation and stabilizer addition, resulting in a nearly two‐fold reduction in estimated emissions compared to either treatment alone. Stepwise regression analysis indicated that variables associated with surface crust strength (aggregate stability, penetration resistance) were negatively associated with emissions and variables associated with sediment supply (sand content, loose sediment cover) were positively associated with emissions. With more time to develop, the soil‐trapping activity and surface integrity of biocrust inoculum and soil stabilizer mixtures is expected to increase with the accumulation of surface biomass and enhancement of roughness through freeze–thaw cycles.

Utah↗
USGS2003

Sonoran Desert: Fragile Land of Extremes

'Sonoran Desert: Fragile Land of Extremes' shows how biologists with the U.S. Geological Survey work with other scientists in an effort to better understand native plants and animals such as desert tortoises, saguaro cacti, and Gila monsters. Much of the program was shot in and around Saguaro National Park near Tucson, Arizona. Genetic detective work, using DNA, focuses on understanding the lives of tortoises. Studies of saguaros over many decades clarify how these amazing plants reproduce and thrive in the desert. Threats from fire, diseases in tortoises, and a growing human population motivate the scientists. Their work to identify how these organisms live and survive is a crucial step for the sound management of biological resources on public lands. This 28-minute program, USGS Open-File Report 03-305, was shot entirely in high definition video and produced by the USGS Western Ecological Research Center and Southwest Biological Science Center; produced and directed by Stephen Wessells, Western Region Office of Communications.

Open-File Report↗
USGS2012

Protocols for collection of streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data to describe stream quality for the Hydrobiological Monitoring Program, Equus Beds Aquifer Storage and Recovery Program, city of Wichita, Kansas

The city of Wichita, Kansas uses the Equus Beds aquifer, one of two sources, for municipal water supply. To meet future water needs, plans for artificial recharge of the aquifer have been implemented in several phases. Phase I of the Equus Beds Aquifer Storage and Recovery (ASR) Program began with injection of water from the Little Arkansas River into the aquifer for storage and subsequent recovery in 2006. Construction of a river intake structure and surface-water treatment plant began as implementation of Phase II of the Equus Beds ASR Program in 2010. An important aspect of the ASR Program is the monitoring of water quality and the effects of recharge activities on stream conditions. Physical, chemical, and biological data provide the basis for an integrated assessment of stream quality. This report describes protocols for collecting streamflow, water-quality, streambed-sediment, periphyton, macroinvertebrate, fish, and habitat data as part of the city of Wichita's hydrobiological monitoring program (HBMP). Following consistent and reliable methods for data collection and processing is imperative for the long-term success of the monitoring program.

Kansas↗
USGS1993

Options for water-level control in developed wetlands

Wetland habitats in the United States currently are lost at a rate of 260,000 acres/year (105,218 ha/year). Consequently, water birds concentrate in fewer and smaller areas. Such concentrations may deplete food supplies and influence behavior, physiology, and survival. Continued losses increase the importance of sound management of the remaining wetlands because water birds depend on them. Human activities modified the natural hydrology of most remaining wetlands in the conterminous United States, and such hydrologic alterations frequently reduce wetland productivity. The restoration of original wetland functions and productivity often requires the development of water distribution and discharge systems to emulate natural hydrologic regimes. Construction of levees and correct placement of control structures and water-delivery and water-discharge systems are necessary to (1) create soil and water conditions for the germination of desirable plants, (2) control nuisance vegetation, (3) promote the production of invertebrates, and (4) make foods available for wildlife that depends of wetlands (Leaflets 13.2.1 and 13.4.6). This paper provides basic guidelines for the design of wetlands that benefit wildlife. If biological considerations are not incorporated into such designs, the capability of managing wetlands for water birds is reduced and costs often are greater. Although we address the development of palustrine wetlands in migration and wintering areas, many of the discussed principles are applicable to the development of other wetland types and in other locations.

Book chapter↗
USGS1998

An enthusiast's guide to agrostology

Book review of: Population Biology of Grasses edited by G.P. Cheplick Cambridge University Press, 1998. £50.00/$85.00 hbk (xii +399 pages) ISBN 0 521 57205 3

Trends in Plant Science↗
USGS1989

The ecology of hydric hammocks: a community profile

This community profile is one in a series of Fish and Wildlife Service publications compiled to provide a state-of-knowledge synthesis of scientific information and literature on various coastal habitats. The subject of this profile is the hydric hammock, a distinctive type of forested wetland occurring at low elevations along the gulf coast of Florida from Aripeka to St. Marks and at various inland sites in Florida. Relatively little research has been conducted in hydric hammocks, and no thorough effort has been made previously to define this community. Consequently, no consensus has existed about the extent and nature of this community; some published works and active researchers have differed in their judgments about it; and the entity sometimes is ignored and often is lumped with other types of mixed hardwood forests. The purpose of this profile is to establish or clarify an identification and understanding of the hydric-hammock community. Information for the profile was gathered from published and unpublished literature, from persona 1 communication with many technical experts, and from our own fie 1 d experience. The profile includes some new data gathered in the field for the purpose of defining this community. It is hoped that the content and format of the profile will be useful to a broad spectrum of users, including other scientists, students, resource managers and planners, teachers, and interested citizens. The profile includes structural and functional aspects of the community: its physical setting, plant and animal composition and dynamics, interactions of its flora and fauna, and its relationships with other communities.

Florida↗
USGS2019

Deer do not affect short-term rates of vegetation recovery in overwash fans on Fire Island after Hurricane Sandy

1. Coastal resilience is threatened as storm-induced disturbances become more frequent and intense with anticipated changes in weather patterns. After severe storms, rapid recovery of vegetation, especially that of dune-stabilizing plants, is a fundamental property of coastal resilience. Herbivores may affect resilience by selectively foraging palatable plant species in disturbed areas. Knowledge of herbivore impacts to dune recovery after storm events is crucial to management of coastal properties. 2. We combined imagery classification, wildlife monitoring, and trend analysis to investigate effects of white-tailed deer on recovery rates of vegetation over four years post-storm in nine areas overwashed. We estimated local deer density with trail cameras, coupled deer density with primary productivity, and assessed the relationship between deer density and rates of vegetation recovery in overwash fans. 3. Pre-storm vegetation cover consisted of shrubs and sporadic patches of beachgrass. Post-storm cover was dominated by beachgrass. At current recovery rates, vegetation coverage will return to pre-storm conditions within the decade, though community transition from grasses to shrubs will take longer and will vary by site with the rate of dune formation. 4. The effect of deer on rates of vegetation recovery was negative, but not statistically significant nor biologically compelling. Although effects of trampling are evident in classified imagery, deer foraging on beachgrass had little effect on rates of spread throughout overwash fans. 5. Our research provides perhaps the first assessment of the effects of deer on post-storm vegetation recovery. While the rate of spread of the primary dune-building plant species was not deleteriously affected by deer, locally high deer densities will likely affect the establishment and development of more palatable herbs and shrubs.

New York↗
USGS1991

The Detroit River: Effects of contaminants and human activities on aquatic plants and animals and their habitats

Despite the extensive urbanization of its watershed, the Detroit River still supports diverse fish and wildlife populations. Conflicting uses of the river for waste disposal, water withdrawals, shipping, recreation, and fishing require innovative management. Chemicals added by man to the Detroit River have adversely affected the health and habitats of the river's plants and animals. In 1985, as part of an Upper Great Lakes Connecting Channels Study sponsored by Environment Canada and the U.S. Environmental Protection Agency, researchers exposed healthy bacteria, plankton, benthic macroinvertebrates, fish, and birds to Detroit River sediments and sediment porewater. Negative impacts included genetic mutations in bacteria; death of macroinvertebrates; accumulation of contaminants in insects, clams, fish, and ducks; and tumor formation in fish. Field surveys showed areas of the river bottom that were otherwise suitable for habitation by a variety of plants and animals were contaminated with chlorinated hydrocarbons and heavy metals and occupied only by pollution-tolerant worms. Destruction of shoreline wetlands and disposal of sewage and toxic substances in the Detroit River have reduced habitat and conflict with basic biological processes, including the sustained production of fish and wildlife. Current regulations do not adequately control pollution loadings. However, remedial actions are being formulated by the U.S. and Canada to restore degraded benthic habitats and eliminate discharges of toxic contaminants into the Detroit River.

Hydrobiologia↗
USGS2017

Using publicly available data to quantify plant–pollinator interactions and evaluate conservation seeding mixes in the Northern Great Plains

Concern over declining pollinators has led to multiple conservation initiatives for improving forage for bees in agroecosystems. Using data available through the Pollinator Library (npwrc.usgs.gov/pollinator/), we summarize plant–pollinator interaction data collected from 2012–2015 on lands managed by the U.S. Fish and Wildlife Service and private lands enrolled in U.S. Department of Agriculture conservation programs in eastern North Dakota (ND). Furthermore, we demonstrate how plant–pollinator interaction data from the Pollinator Library and seed cost information can be used to evaluate hypothetical seeding mixes for pollinator habitat enhancements. We summarize records of 314 wild bee and 849 honey bee ( Apis mellifera L.) interactions detected on 63 different plant species. The wild bee observations consisted of 46 species, 15 genera, and 5 families. Over 54% of all wild bee observations were represented by three genera ― Bombus , Lassioglossum , and Melissodes . The most commonly visited forbs by wild bees were Monarda fistulosa , Sonchus arvensis , and Zizia aurea . The most commonly visited forbs by A. mellifera were Cirsium arvense , Melilotus officinalis , and Medicago sativa . Among all interactions, 13% of A. mellifera and 77% of wild bee observations were made on plants native to ND. Our seed mix evaluation shows that mixes may often need to be tailored to meet the unique needs of wild bees and managed honey bees in agricultural landscapes. Our evaluation also demonstrates the importance of incorporating both biologic and economic information when attempting to design cost-effective seeding mixes for supporting pollinators in a critically important part of the United States.

Environmental Entomology↗
USGS2002

Meeting ecological and societal needs for freshwater

Human society has used freshwater from rivers, lakes, groundwater, and wetlands for many different urban, agricultural, and industrial activities, but in doing so has overlooked its value in supporting ecosystems. Freshwater is vital to human life and societal well-being, and thus its utilization for consumption, irrigation, and transport has long taken precedence over other commodities and services provided by freshwater ecosystems. However, there is growing recognition that functionally intact and biologically complex aquatic ecosystems provide many economically valuable services and long-term benefits to society. The short-term benefits include ecosystem goods and services, such as food supply, flood control, purification of human and industrial wastes, and habitat for plant and animal life—and these are costly, if not impossible, to replace. Long-term benefits include the sustained provision of those goods and services, as well as the adaptive capacity of aquatic ecosystems to respond to future environmental alterations, such as climate change. Thus, maintenance of the processes and properties that support freshwater ecosystem integrity should be included in debates over sustainable water resource allocation. The purpose of this report is to explain how the integrity of freshwater ecosystems depends upon adequate quantity, quality, timing, and temporal variability of water flow. Defining these requirements in a comprehensive but general manner provides a better foundation for their inclusion in current and future debates about allocation of water resources. In this way the needs of freshwater ecosystems can be legitimately recognized and addressed. We also recommend ways in which freshwater ecosystems can be protected, maintained, and restored. Freshwater ecosystem structure and function are tightly linked to the watershed or catchment of which they are a part. Because riverine networks, lakes, wetlands, and their connecting groundwaters, are literally the “sinks” into which landscapes drain, they are greatly influenced by terrestrial processes, including many human uses or modifications of land and water. Freshwater ecosystems, whether lakes, wetlands, or rivers, have specific requirements in terms of quantity, quality, and seasonality of their water supplies. Sustainability normally requires these systems to fluctuate within a natural range of variation. Flow regime, sediment and organic matter inputs, thermal and light characteristics, chemical and nutrient characteristics, and biotic assemblages are fundamental defining attributes of freshwater ecosystems. These attributes impart relatively unique characteristics of productivity and biodiversity to each ecosystem. The natural range of variation in each of these attributes is critical to maintaining the integrity and dynamic potential of aquatic ecosystems; therefore, management should allow for dynamic change. Piecemeal approaches cannot solve the problems confronting freshwater ecosystems. Scientific definitions of the requirements to protect and maintain aquatic ecosystems are necessary but insufficient for establishing the appropriate distribution between societal and ecosystem water needs. For scientific knowledge to be implemented science must be connected to a political agenda for sustainable development. We offer these recommendations as a beginning to redress how water is viewed and managed in the United States: (1) Frame national and regional water management policies to explicitly incorporate freshwater ecosystem needs, particularly those related to naturally variable flow regimes and to the linking of water quality with water quantity; (2) Define water resources to include watersheds, so that freshwaters are viewed within a landscape, or systems context; (3) Increase communication and education across disciplines, especially among engineers, hydrologists, economists, and ecologists to facilitate an integrated view of freshwater resources; (4) Increase restoration efforts, using well-grounded ecological principles as guidelines; (5) Maintain and protect the remaining freshwater ecosystems that have high integrity; and (6) Recognize the dependence of human society on naturally functioning ecosystems.

Ecological Applications↗