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At least 685 records · Page 38Linked to original sources
USGS2011

Crims Island-Restoration and monitoring of juvenile salmon rearing habitat in the Columbia River Estuary, Oregon, 2004-10

Under the 2004 Biological Opinion for operation of the Federal Columbia River Power System released by the National Marine Fisheries Service, the U.S. Army Corps of Engineers (USACE), the Bonneville Power Administration (BPA), and the Bureau of Reclamation (Reclamation) were directed to restore more than 4,047 hectares (10,000 acres) of tidal marsh in the Columbia River estuary by 2010. Restoration of Crims Island near Longview, Washington, restored 38.1 hectares of marsh and swamp in the tidal freshwater portion of the lower Columbia River. The goal of the restoration was to improve habitat for juveniles of Endangered Species Act (ESA)-listed salmon stocks and ESA-listed Columbian white-tailed deer. The U.S. Geological Survey (USGS) monitored and evaluated the fisheries and aquatic resources at Crims Island in 2004 prior to restoration (pre-restoration), which began in August 2004, and then post-restoration from 2006 to 2009. This report summarizes pre- and post-restoration monitoring data used by the USGS to evaluate project success. We evaluated project success by examining the interaction between juvenile salmon and a suite of broader ecological measures including sediments, plants, and invertebrates and their response to large-scale habitat alteration. The restoration action at Crims Island from August 2004 to September 2005 was to excavate a 0.6-meter layer of soil and dig channels in the interior of the island to remove reed canary grass and increase habitat area and tidal exchange. The excavation created 34.4 hectares of tidal emergent marsh where none previously existed and 3.7 hectares of intertidal and subtidal channels. Cattle that had grazed the island for more than 50 years were relocated. Soil excavated from the site was deposited in upland areas next to the tidal marsh to establish an upland forest. Excavation deepened and widened an existing T-shaped channel to increase tidal flow to the interior of the island. The western arm of the existing 'T-channel' was extended westward and connected to Bradbury Slough to create a second outlet to the main river. New intertidal channels were constructed from the existing 'T-channel' and tidal mudflats became inundated at high tide to increase rearing habitat for juvenile salmonids. The restoration action resulted in a 95-percent increase in available juvenile salmon rearing habitat. We collected juvenile salmon and other fishes at Crims Island and a nearby reference site using beach seines and fyke nets annually from March through August during all years. Benthic invertebrates were collected with sediment corers and drift invertebrates were collected with neuston nets. Juvenile salmon stomach contents were sampled using lavage. Vegetation and sediments characteristics were surveyed and we conducted a topographic/bathymetric survey using a RTK (real time kinematic) GPS (global positioning system). The fish assemblage at Crims Island, composed primarily of threespine stickleback (Gasterosteus aculeatus), non-native banded killifish (Fundulus diaphanus), peamouth chub (Mylocheilus caurinus), subyearling Chinook salmon (Oncorhynchus tshawytscha) (hereinafter referred to as subyearlings), and small numbers of juvenile chum salmon (Oncorhynchus keta), did not differ appreciably pre- and post-restoration. Subyearlings were the primary salmonid collected and were seasonally abundant from April through May during all years. The abundance of juvenile salmon declined seasonally as water temperature exceeded 20 degrees C in the Reference site by mid-June; however, subyearlings persisted at the Mainstem site and in subtidal channels of the Restoration site through the summer in water temperatures exceeding 22 degrees C. Residence times of subyearlings in Crims Island backwaters generally were short consisting of one or two tidal cycles. Median residence time was longer in the Restoration site than in the Reference site pre- and post-restoration. Small (mean = 55.7 millimeters) subyea

Scientific Investigations Report↗
USGS1991

User's guide to the wetland creation/restoration data base, version 2

Wetland creation or restoration projects are frequently proposed as mitigation for unavoidable wetland losses, as components of wetland enhancement programs, and as tools to accomplish specific objectives such as waterfowl production or flood control. There is considerable controversy concerning the effectiveness of such projects as well as the most appropriate and efficient techniques to employ. The importance of the resource and the long time scales involved in fully evaluating a creation or restoration effort make it imperative to consider existing information as fully as possible in the development and evaluation of wetland creation or restoration proposals. To aid in the evaluation of wetland/creation efforts, the U.s. Fish and Wildlife Service (FWS), National Ecology Research Center, has developed the Wetland Creation/Restoration (WCR) Data Base. The data base is a highly indexed or keyworded bibliography of wetland creation or restoration articles. ("Articles" refers to any type of publication that deals specifically with wetland creation/restoration projects or studies.) The scope of the articles is international, although most of them are concerned with projects conducted in the United States. Information coded for each article includes author; citation; type of wetland and its location in terms of state, ecoregion, and FWS region; type of study undertaken; objectives in creating or restoring the wetland; actions performed to realize those objectives; length of time encompassed by the study; evaluation of results and responses to the wetland creation/restoration actions; and a listing of plant species significant to the project. A brief annotation summarizes the article and includes any significant additional information that may not be adequately reflected in the above described fields. Many of these articles describe only one or two components of a total wetland restoration effort. Planning a project that is designed to restore a wetland system (including at least some of its functions) is similar to constructing a picture from a number of puzzle pieces--missing pieces represent data gaps or information that is not available. Articles range from specific case studies, to overviews of restoration methods and techniques, to planning restoration projects and assessing programmatic and administrative backgrounds and interactions. In this data base, the term "restoration" is applied loosely to include rehabilitation of wetlands. It may refer to a number of situations or actions including, but not limited to: 1. breaching dikes or plugging drains; 2. water pollution clean-up; 3. conversion of eutrophic conditions; 4. wastewater treatment; 5. recolonization of previously disturbed or denuded areas; 6. amelioration of adverse conditions (erosion, wave, or wind action); 7. soil treatment --mulching, fertilization; 8. rerouting streams --may include construction of meander patterns; 9. monitoring natural vegetation; or 0. excluding grazers (geese, cattle) and monitoring results. This report describes the format and content of Version 2 of the WCR data base. Version 2 differs from the previous version described in SchnellerMcDonald et al. (1988): several fields have been dropped and condensed and new records have been added. Version 2 includes all records distributed with the earlier version and its updates. We recommend you replace any previous version with Version 2.

Book↗
USGS2024

Hydrodynamic and salinity tesponse to tidal restoration in the Herring River Estuary, MA, considering present and future sea levels

Coastal salt marshes are crucial ecosystems that provide habitat for a variety of species, improve water quality, and play a major role in the global carbon cycle. However, many salt marshes have been severely damaged by human activities such as diking and draining for urban development. Recently, there has been a noticeable shift toward the prioritization of coastal marsh restoration to re-establish their ecosystem services. The removal of anthropogenic barriers such as dikes, sluices, and culverts is a critical component of many projects because it allows for the restoration of tidal flow to support natural hydrologic regimes and salinity conditions, which play a dominant role in determining the ecological and biogeochemical functioning of marshes. This study examines how proposed removal of hydraulic structures will influence the hydrologic potential for marsh restoration in the Herring River Estuary in Cape Cod, Massachusetts, USA. Construction of dikes, roadways, and low-capacity culverts over the last century has substantially restricted tidal flow in the Herring River Estuary, leading to degradation of salt marsh habitat. The estuary is now undergoing the first phase of a restoration project to re-introduce natural hydrologic conditions, increase salinity, and restore salt marsh habitat. To assess how the Herring River Estuary will respond to human- and climate-driven modifications, we develop and apply a validated hydrodynamic model to simulate the complex tidal and salinity dynamics of the estuary under a range of restoration and sea level rise scenarios. We then quantify how salinity and critical hydrologic variables, including tidal range and depth of mean high water, will evolve for various restoration scenarios considering present and future sea levels. The results of this research can inform coastal management and restoration plans that re-create the natural functioning of the system while protecting critical infrastructure and reducing the risk of restoration failure.

Massachusetts↗
USGS2016

Filling the interspace—restoring arid land mosses: source populations, organic matter, and overwintering govern success

Biological soil crusts contribute to ecosystem functions and occupy space that could be available to invasive annual grasses. Given disturbances in the semiarid shrub steppe communities, we embarked on a set of studies to investigate restoration potential of mosses in sagebrush steppe ecosystems. We examined establishment and growth of two moss species common to the Great Basin, USA: Bryum argenteum and Syntrichia ruralis from two environmental settings (warm dry vs. cool moist). Moss fragments were inoculated into a third warm dry setting, on bare soil in spring and fall, both with and without a jute net and with and without spring irrigation. Moss cover was monitored in spring seasons of three consecutive years. Both moss species increased in cover over the winter. When Bryum received spring irrigation that was out of sync with natural precipitation patterns, moss cover increased and then crashed, taking two seasons to recover. Syntrichia did not respond to the irrigation treatment. The addition of jute net increased moss cover under all conditions, except Syntrichia following fall inoculation, which required a second winter to increase in cover. The warm dry population of Bryum combined with jute achieved on average 60% cover compared to the cool moist population that achieved only 28% cover by the end of the study. Differences were less pronounced for Syntrichia where moss from the warm dry population with jute achieved on average 51% cover compared to the cool moist population that achieved 43% cover by the end of the study. Restoration of arid land mosses may quickly protect soils from erosion while occupying sites before invasive plants. We show that higher moss cover will be achieved quickly with the addition of organic matter and when moss fragments originate from sites with a climate that is similar to that of the restoration site.

Ecology and Evolution↗
USGS2020

Spatial grain of adaptation is much finer than ecoregional-scale common gardens reveal

Adaptive variation among plant populations must be known for effective conservation and restoration of imperiled species and predicting their responses to a changing climate. Common‐garden experiments, in which plants sourced from geographically distant populations are grown together such that genetic differences may be expressed, have provided much insight on adaptive variation. Common‐garden experiments also form the foundation for climate‐based seed‐transfer guidelines. However, the spatial scale at which population differentiation occurs is rarely addressed, leaving a critical information gap for parameterizing seed‐transfer guidelines and assessing species’ climate vulnerability. We asked whether adaptation was evident among populations of a foundational perennial within a single “empirical” seed‐transfer zone (based on previous common‐garden findings evaluating very distant populations) but different “provisional” seed zones (groupings of areas of similar climate and are not parameterized from common‐garden data). Seedlings from three populations originating from similar conditions within an intermediate elevation were planted into gardens nearby at the same elevation, or 250–450 m higher or lower in elevation and 0.4–25 km away. Substantial variation was observed between gardens in survival (ranging 2%–99%), foliar crown volume (7.8–22.6 dm 3 ), and reproductive effort (0%–65%), but not among the three transplanted populations. The between garden variation was inversely related to climatic differences between the gardens and seed‐source populations, specifically the site differences in maximum–minimum annual temperatures. Results suggest that substantial site‐specificity in adaptation can occur at finer scales than is accounted for in empirical seed‐transfer guidance when the guidance is derived from broadscale common‐garden studies. Being within the same empirical seed zone, geographic unit, and even within 10 km distance may not qualify as “local” in the context of seed transfer. Moving forward, designing common‐garden experiments so that they allow for testing the scale of adaptation will help in translating the resulting seed‐transfer guidance to restoration projects.

Idaho↗
USGS2025

Evaluating effectiveness of flocculation and wave-reduction barriers for restoration of a turbid, terminal lake

Malheur Lake is a freshwater, shallow lake that provides key habitat for birds along the Pacific Flyway in North America. The lake shifted to a turbid state in the 1990s with suspended-sediment concentrations sometimes exceeding 1000 mg/L and minimal light available in the water column for submerged aquatic vegetation. Resource managers intend to enhance bird habitat quality by restoring the lake to a clear, vegetated state. Ten mesocosms were installed to experimentally test the effects of wave-reduction barriers and flocculation (aluminum sulfate followed by lanthanum-modified bentonite clay) on dependent variables including turbidity, suspended-sediment concentrations, nutrient concentrations, and photosynthetically active radiation. Flocculation additions temporarily decreased turbidity by ≥ 90% and significantly increased photosynthetically active radiation by > 400% through the water column. Orthophosphate concentrations significantly decreased following the first flocculation addition. The clay did not cap the flocculated material, and turbidity increased within a few days from wind-wave action. Wind directions in the middle of the lake were variable, minimizing the effect of wave-reduction barriers on dependent variables. This study showed that the light required for submerged aquatic vegetation can be temporarily attained at the lakebed using flocculation. Future experiments could attempt to prolong the duration of low turbidity by effectively capping the flocculated material. The findings demonstrate the complexity of disrupting shallow lake feedback loops and offer insights for turbid-state lake restoration.

Oregon↗
USGS1999

Modeling the effects of land use and climate change on riverine smallmouth bass

Anthropogenic changes in temperature and stream flow, associated with watershed land use and climate change, are critical influences on the distribution and abundance of riverine fishes. To project the effects of changing land use and climate, we modeled a smallmouth bass ( Micropterus dolomieu ) population in a midwestern USA, large river–floodplain ecosystem under historical (1915–1925), present (1977–1990), and future (2060, influenced by climate change) temperature and flow regimes. The age-structured model included parameters for temperature and river discharge during critical seasonal periods, fish population dynamics, and fishing harvest. Model relationships were developed from empirical field data collected over a 13-yr period. Sensitivity analyses indicated that discharge during the spawning/rearing period had a greater effect on adult density and fishing yield than did spawning/rearing temperature or winter discharge. Simulations for 100 years projected a 139% greater mean fish density under a historical flow regime (64.9 fish/ha) than that estimated for the present (27.1 fish/ha) with a sustainable fishing harvest under both flow regimes. Simulations under future climate-change-induced temperature and flow regimes with present land use projected a 69% decrease in mean fish density (8.5 fish/ha) from present and an unstable population that went extinct during 56% of the simulations. However, when simulated under a future climate-altered temperature and flow regime with historical land use, the population increased by 66% (45.0 fish/ha) from present and sustained a harvest. Our findings suggest that land-use changes may be a greater detriment to riverine fishes than projected climate change and that the combined effects of both factors may lead to local species extinction. However, the negative effects of increased temperature and precipitation associated with future global warming could be mitigated by river channel, floodplain, and watershed restoration.

Ecological Applications↗
USGS2001

Our evolving conceptual model of the coastal eutrophication problem

A primary focus of coastal science during the past 3 decades has been the question: How does anthropogenic nutrient enrichment cause change in the structure or function of nearshore coastal ecosystems? This theme of environmental science is recent, so our conceptual model of the coastal eutrophication problem continues to change rapidly. In this review, I suggest that the early (Phase I) conceptual model was strongly influenced by limnologists, who began intense study of lake eutrophication by the 1960s. The Phase I model emphasized changing nutrient input as a signal, and responses to that signal as increased phytoplankton biomass and primary production, decomposition of phytoplankton-derived organic matter, and enhanced depletion of oxygen from bottom waters. Coastal research in recent decades has identified key differences in the responses of lakes and coastal-estuarine ecosystems to nutrient enrichment. The contemporary (Phase II) conceptual model reflects those differences and includes explicit recognition of (1) system-specific attributes that act as a filter to modulate the responses to enrichment (leading to large differences among estuarine-coastal systems in their sensitivity to nutrient enrichment); and (2) a complex suite of direct and indirect responses including linked changes in: water transparency, distribution of vascular plants and biomass of macroalgae, sediment biogeochemistry and nutrient cycling, nutrient ratios and their regulation of phytoplankton community composition, frequency of toxic/harmful algal blooms, habitat quality for metazoans, reproduction/growth/survival of pelagic and benthic invertebrates, and subtle changes such as shifts in the seasonality of ecosystem functions. Each aspect of the Phase II model is illustrated here with examples from coastal ecosystems around the world. In the last section of this review I present one vision of the next (Phase III) stage in the evolution of our conceptual model, organized around 5 questions that will guide coastal science in the early 21st century: (1) How do system-specific attributes constrain or amplify the responses of coastal ecosystems to nutrient enrichment? (2) How does nutrient enrichment interact with other stressors (toxic contaminants, fishing harvest, aquaculture, nonindigenous species, habitat loss, climate change, hydrologic manipulations) to change coastal ecosystems? (3) How are responses to multiple stressors linked? (4) How does human-induced change in the coastal zone impact the Earth system as habitat for humanity and other species? (5) How can a deeper scientific understanding of the coastal eutrophication problem be applied to develop tools for building strategies at ecosystem restoration or rehabilitation?

Marine Ecology Progress Series↗
USGS2018

Bank‐derived material dominates fluvial sediment in a suburban Chesapeake Bay watershed

Excess fine sediment is a leading cause of ecological degradation within the Chesapeake Bay watershed. To effectively target sediment mitigation measures, it is necessary to identify and quantify the delivery of sediment sources to local waterbodies. This study examines the contributions of sediment sources within Upper Difficult Run, a suburbanized watershed in Fairfax County, Virginia. A source sediment library was constructed from stream banks, forest soils, and road dust. Target sediments were collected from fine channel deposits and suspended sediment during 16 storm events from 2008 to 2012. Apportionment of targets to sources was performed using Sed_SAT, a publicly available toolkit for sediment fingerprinting. Bed sediment was dominated by stream bank material (mean: 98%), with minor contributions from forests (2%). Suspended fine sediments were also dominated by stream banks (suspended sediment concentration‐weighted mean: 91%), with minor contributions from roads (8%) and forests (<1%). Stream banks dominated at all discharges, and on the rising limb and at peak flow, sediment concentrations increased due to bank material rather than surface erosion. Sediment budget data indicated that direct bank erosion was insufficient to account for the suspended load derived from stream banks. However, bank‐derived sediment re‐mobilized from in‐channel storage could account for this difference and, combined, resulted in a sediment delivery ratio of 0.847 for all bank‐derived sediments. Results demonstrate that stream bank erosion is responsible for the majority of fine sediment in this suburban watershed of the Chesapeake Bay drainage area. Thus, management actions to control upland sources of sediment may have limited effect on the sediment conditions of Upper Difficult Run, whereas efforts focusing on bank stabilization, channel restoration, and/or stormwater management to reduce bank erosion may improve the ecological condition of these waterbodies.

Virginia↗
USGS2023

What evidence exists on the ecological and physical effects of built structures in shallow, tropical coral reefs? A systematic map protocol

Background Shallow, tropical coral reefs face compounding threats from habitat degradation due to coastal development and pollution, impacts from storms and sea-level rise, and pulse disturbances like blast fishing, mining, dredging, and ship groundings that reduce coral reefs’ height and variability. One approach toward restoring coral reef structure from these threats is deploying built structures. Built structures range from engineered modules and repurposed materials to underwater sculptures and intentionally placed natural rocks. Restoration practitioners and coastal managers increasingly consider incorporating built structures, including nature-based solutions, into coral reef-related applications. Yet, synthesized evidence on the ecological and physical performance of built structure interventions across a variety of contexts (e.g., restoration, coastal protection, mitigation, tourism) is not readily available to guide decisions. To help inform management decisions, here we aim to document the global evidence base on the ecological and physical performance of built structures in shallow (≤ 30 m) tropical (35° N to 35° S latitude) coral ecosystems. The collated evidence base on use cases and associated ecological and physical outcomes of built structure interventions can help inform future consideration of built structures in reef restoration design, siting, and implementation. Method To discover evidence on the performance of built structures in coral reef-related applications, such as restoration, mitigation, and coastal protection, primary literature will be searched across indexing platforms, bibliographic databases, open discovery citation indexes, a web-based search engine, a novel literature discovery tool, and organizational websites. The geographic scope of the search is global, and there is no limitation to temporal scope. Primary literature will be screened first at the level of title and abstract and then at the full text level against defined eligibility criteria for the population, intervention, study type, and outcomes of interest. Metadata will be extracted from studies that pass both screening levels. The resulting data will be analyzed to determine the distribution and abundance of evidence. Results will be made publicly available and reported in a systematic map that includes a narrative description, identifies evidence clusters and gaps, and outlines future research directions on the use of built structures in coral reef-related applications.

Environmental Evidence↗
USGS2018

Ecological drought: Accounting for the non-human impacts of water shortage in the Upper Missouri Headwaters Basin, Montana, USA

Water laws and drought plans are used to prioritize and allocate scarce water resources. Both have historically been human-centric, failing to account for non-human water needs. In this paper, we examine the development of instream flow legislation and the evolution of drought planning to highlight the growing concern for the non-human impacts of water scarcity. Utilizing a new framework for ecological drought, we analyzed five watershed-scale drought plans in southwestern Montana, USA to understand if, and how, the ecological impacts of drought are currently being assessed. We found that while these plans do account for some ecological impacts, it is primarily through the narrow lens of impacts to fish as measured by water temperature and streamflow. The latter is typically based on the same ecological principles used to determine instream flow requirements. We also found that other resource plans in the same watersheds (e.g., Watershed Restoration Plans, Bureau of Land Management (BLM) Watershed Assessments or United States Forest Service (USFS) Forest Plans) identify a broader range of ecological drought risks. Given limited resources and the potential for mutual benefits and synergies, we suggest greater integration between various planning processes could result in a more holistic consideration of water needs and uses across the landscape.

Montana↗
USGS2006

Forecasting selenium discharges to the San Francisco Bay-Delta Estuary: Ecological effects of a proposed San Luis Drain extension

Selenium discharges to the San Francisco Bay-Delta Estuary (Bay-Delta) could change significantly if federal and state agencies (1) approve an extension of the San Luis Drain to convey agricultural drainage from the western San Joaquin Valley to the North Bay (Suisun Bay, Carquinez Strait, and San Pablo Bay); (2) allow changes in flow patterns of the lower San Joaquin River and Bay-Delta while using an existing portion of the San Luis Drain to convey agricultural drainage to a tributary of the San Joaquin River; or (3) revise selenium criteria for the protection of aquatic life or issue criteria for the protection of wildlife. Understanding the biotransfer of selenium is essential to evaluating effects of selenium on Bay-Delta ecosystems. Confusion about selenium threats to fish and wildlife stem from (1) monitoring programs that do not address specific protocols necessary for an element that bioaccumulates; and (2) failure to consider the full complexity of the processes that result in selenium toxicity. Past studies show that predators are more at risk from selenium contamination than their prey, making it difficult to use traditional methods to predict risk from environmental concentrations alone. This report presents an approach to conceptualize and model the fate and effects of selenium under various load scenarios from the San Joaquin Valley. For each potential load, progressive forecasts show resulting (1) water-column concentration; (2) speciation; (3) transformation to particulate form; (4) particulate concentration; (5) bioaccumulation by invertebrates; (6) trophic transfer to predators; and (7) effects on those predators. Enough is known to establish a first-order understanding of relevant conditions, biological response, and ecological risks should selenium be discharged directly into the North Bay through a conveyance such as a proposed extension of the San Luis Drain. The approach presented here, the Bay-Delta selenium model, determines the mass, fate, and effects of selenium released to the Bay-Delta through use of (1) historical land-use, drainage, alluvial-fill, and runoff databases; (2) existing knowledge concerning biogeochemical reactions and physiological parameters of selenium (e.g., speciation, partitioning between dissolved and particulate forms, and bivalve assimilation efficiency); and (3) site-specific data mainly from 1986 to 1996 for clams and bottom-feeding fish and birds. Selenium load scenarios consider effluents from North Bay oil refineries and discharges of agricultural drainage from the San Joaquin Valley to enable calculation of (a) a composite freshwater endmember selenium concentration at the head of the estuary; and (b) a selenium concentration at a selected seawater location (Carquinez Strait) as a foundation for modeling. Analysis of selenium effects also takes into account the mode of conveyance for agricultural drainage (i.e., the San Luis Drain or San Joaquin River); and flows of the Sacramento River and San Joaquin River on a seasonal or monthly basis. Load scenarios for San Joaquin Valley mirror predictions made since 1955 of a worsening salt (and by inference, selenium) build-up exacerbated by an arid climate and massive irrigation. The reservoir of selenium in the San Joaquin Valley is sufficient to provide loading at an annual rate of approximately 42,500 pounds of selenium to a Bay-Delta disposal point for 63 to 304 years at the lower range of projections presented here, even if influx of selenium from the California Coast Ranges could be curtailed. Disposal of wastewaters on an annual basis outside of the San Joaquin Valley may slow the degradation of valley resources, but drainage alone cannot alleviate the salt and selenium build-up in the San Joaquin Valley, at least within a century. Load scenarios also show the different proportions of selenium loading to the Bay-Delta. Oil refinery loads from 1986 to 1992 ranged from 8.5 to 20 pounds of selenium per day; with treatment and cleanup, loads decreased to 3.0 pounds of selenium per day in 1999. In contrast, San Joaquin Valley agricultural drainage loads disposed of in a San Luis Drain extension could range from 45 to 117 pounds of selenium per day across a set of historical and future conditions. Components of this valley-wide load include five source subareas (i.e., Grassland, Westlands, Tulare, Kern, and Northern) defined by water and drainage management. Loads vary per subarea mainly because of proximity of the subarea to geologic sources of selenium and irrigation history. Loads from the Sacramento River, depending on flow conditions, range from 0.8 to 10 pounds of selenium per day. Loads from the San Joaquin River vary depending on restoration and flow conditions, which are considered. A consistent picture of ecological risk emerges under modeled selenium discharges from a proposed San Luis Drain extension. The threat to the estuary is greatest during low flow seasons and critically dry years. Where selenium undergoes reactions typical of low flow or longer residence time, highly problematic bioaccumulation in prey (food) is forecast. Surf scoter, greater and lesser scaup, and white sturgeon appear to be most at risk because these Bay-Delta predators feed on deposit and filter-feeding bivalves. Recent findings add Sacramento splittail and Dungeness crab to that list. During the low flow season of critically dry years, forecasted selenium concentrations in water, particulate matter, prey (diet), and predator tissue exceed guidelines with a high certainty of producing adverse effects under the most likely load scenario from a proposed San Luis Drain extension. High flows afford some protection under certain conditions in modeled San Joaquin River scenarios. However, meeting a combined goal of releasing a specific load during maximum flows and keeping selenium concentrations in the river below a certain objective to protect against bioaccumulation may not always be attainable. Management of the San Joaquin River on a constant concentration basis also could create problematic bioaccumulation during a wet year, especially during the low flow season, because high flows translate to high loads that are not always offset by seasonal river inflows. Prior to refinery cleanup, selenium contamination was sufficient to threaten reproduction in key species within the Bay-Delta ecosystems and human health advisories were posted based on selenium concentrations in tissues of diving ducks. During this time, selenium concentrations in the Bay-Delta were well below the most stringent recommended water quality criterion [1 microgram per liter (1 µg/L)]. Enhanced biogeochemical transformations to bioavailable particulate selenium and efficient bioaccumulation by bivalves characterized the system. If these biogeochemical conditions continue to prevail and agricultural selenium sources replace or exceed refinery sources, ecological forecasts suggest the risk of adverse effects will be difficult to eliminate under an out-of-valley resolution to the selenium problem. The Bay-Delta selenium model presented here is a systematic approach for conducting forecasts of the ecological effects from selenium on aquatic food webs. It is a new tool that links and models the major processes leading from loads through consumer organisms to predators. It also is a feasible approach for site-specific analysis and could provide a framework for developing new protective selenium foodweb guidelines and predator criteria. Model components that help ensure understanding ecosystems and the basis of environmental protection are (1) contaminant concentrations and speciation in sources, such as particulate material, that most influence bioavailability; (2) bioaccumulation models that calculate concentrations in diet, specifically in bivalves of the Bay-Delta that act as sensitive indicators of selenium contamination; (3) food-web type that determines what animals are threatened and when; and (4) multiple media concentrations (water, particulate material, and tissue of prey and predators) that, in-combination, determine risk or hazard.

California↗
USGS2014

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

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

Florida↗
USGS2025

Impacts of flowering rush (Butomus umbellatus L.) on macrophyte diversity and composition in the Upper Mississippi River

Flowering rush ( Butomus umbellatus L.), a perennial plant native to Eurasia, made a widespread appearance in the Upper Mississippi River in the United States in 2020, following extremely high river discharge during the previous year. Flowering rush expanded rapidly and was found at 1–10% of sites (n = 6,630 total sites) across a 400 km river reach within the first 4 years of invasion. Flowering rush invaded at least 12 of 31 wetland vegetation classes, including submersed aquatic, rooted-floating, deep marsh, and shallow marsh. Analysis of long-term macrophyte data and our targeted field study revealed that plant diversity declined with greater abundance of flowering rush over a 4-year early invasion period, suggesting that native species were displaced. Furthermore, species correlation plots showed a significant negative correlation (r < -0.1) between flowering rush and several native species, including wild celery, water stargrass, and wild rice. Non-metric multi-dimensional scaling (NMDS) ordination placed flowering rush near the center of the plot, which may indicate tolerance to a wide range of environmental conditions such as water depth, flow, and substrate. Centering on the NMDS plot also shows that flowering rush invades many types of vegetated aquatic land cover classes, which was also supported by our geographic information systems analysis of land cover invasion. These habitat associations and ecological impacts of the recent, widespread invasion of flowering rush in the Upper Mississippi River can help inform restoration and management actions during early invasion. Continuing long-term data collection can break limitations on modeling cause-effect relationships and provide insights to the future ecological trajectory of the macrophyte community to this non-native invasive species.

Illinois, Iowa, Minnesota, Wisconsin↗
USGS2022

Influence of riparian thinning on trophic pathways supporting stream food webs in forested watersheds

Resource managers seek to thin second-growth riparian forests to address multiple stream and riparian management objectives, including enhancing aquatic productivity via light-mediated trophic pathways in watersheds of the Pacific Northwest (USA). However, such increases in aquatic productivity depend on complex food web dynamics that link riparian forests and streams. To evaluate how riparian forest thinning influences stream food webs, we conducted a replicated, manipulative field experiment in three northern California watersheds composed of second-growth redwood forests and tracked responses across multiple trophic levels (periphyton, macroinvertebrates, amphibians, and fish) 1 year pre- and post-treatment. Riparian thinning treatments increased light to the stream channel, yet we observed mixed responses by stream food webs. Thinning did not change stream periphyton biomass on natural substrates but increased periphyton accrual on ceramic tiles. Periphyton accrual appeared to be partially muted by top-down effects from invertebrate scrapers, which were more abundant in thinned reaches. Prey in the diets of top predators—coastal giant salamanders ( Dicamptodon tenebrosus ) and coastal cutthroat trout ( Oncorhynchus clarkii clarkii )—did not change in biomass, composition, or structure in response to thinning and instead varied more seasonally and between predators. Stable isotope analysis indicated that shifts in carbon (δ 13 C) signatures of stream periphyton associated with thinning were reflected to varying extents by primary consumers but did not propagate up to top predators. Top predator biomass responses varied between species, where salamander biomass remained unchanged, but cutthroat trout biomass increased slightly in thinned reaches. However, trout biomass responses were not supported by diets or isotopes and correlated weakly with changes in light associated with thinning, suggesting little evidence that responses could be attributed directly to changes in autotrophic pathways. Furthermore, we found no evidence that local trophic responses to thinning propagated into downstream reaches. Taken together, we observed that trophic pathways supporting stream food webs remained largely intact immediately after riparian thinning treatments. Collectively, these results suggest that riparian thinning does not necessarily enhance aquatic productivity in forested streams, indicating that contextual factors driving realized ecological responses should be accounted for when considering thinning as a restoration strategy for stream–riparian ecosystems.

California↗
USGS2018

A social–ecological perspective for riverscape management in the Columbia River Basin

Riverscapes are complex, landscape-scale mosaics of connected river and stream habitats embedded in diverse ecological and socioeconomic settings. Social–ecological interactions among stakeholders often complicate natural-resource conservation and management of riverscapes. The management challenges posed by the conservation and restoration of wild salmonid populations in the Columbia River Basin (CRB) of western North America are one such example. Because of their ecological, cultural, and socioeconomic importance, salmonids present a complex management landscape due to interacting environmental factors (eg climate change, invasive species) as well as socioeconomic and political factors (eg dams, hatcheries, land-use change, transboundary agreements). Many of the problems in the CRB can be linked to social–ecological interactions occurring within integrated ecological, human–social, and regional–climatic spheres. Future management and conservation of salmonid populations therefore depends on how well the issues are understood and whether they can be resolved through effective communication and collaboration among ecologists, social scientists, stakeholders, and policy makers.

Columbia River Basin↗
USGS2024

Documentation of a probable spawning run of cisco Coregonus artedi in the Spanish River, Ontario, Canada

Coregonines were historically diverse and abundant in the Laurentian Great Lakes but declined throughout the 19th and 20th centuries due to multiple factors, including overfishing, habitat degradation, and interactions with invasive species. Great Lakes fishery managers are now working to restore coregonines across the basin. An important aspect of restoration efforts is the identification of key habitats, such as spawning habitats. Our understanding of the extent and diversity of coregonine spawning habitats in the Great Lakes is limited. Historical accounts suggest some cisco Coregonus artedi migrated to tributaries to spawn, but contemporary runs have not been reported. Moreover, cisco display considerable phenotypic variation, with different “forms” often occupying specific habitats or regions. We provide evidence for a previously undocumented spawning run of cisco in the Spanish River, a tributary to the North Channel of Lake Huron. We captured 31 mature and ripe fish (25 males, 6 females) approximately 52 km upstream of the river mouth on 15–16 November 2022. The fish ranged in age from 3-9 yr and total length from 287-394 mm. Of these 31 individuals, 27 were morphologically similar to C. artedi manitoulinus , a subspecies of cisco found in the North Channel; however, four individuals more closely resembled cisco captured in other areas of Lake Huron. These findings represent the best evidence of tributary spawning by cisco since the 1880s, and they have important implications for coregonine conservation and restoration efforts. Ongoing work aims to augment our understanding of the ecological and evolutionary importance of this population.

Ontario↗
USGS2019

The application of oyster reefs in shoreline protection: Are we over‐engineering for an ecosystem engineer?

Oyster reef living shorelines have been proposed as an effective alternative to traditional coastal defence structures (e.g. bulkheads, breakwaters), with the benefit that they may keep pace with sea‐level rise and provide co‐benefits, such as habitat provision. However, there remains uncertainty about the effectiveness of shoreline protection provided by oyster reefs, which limits their broader application. We draw evidence from studies along the east and gulf coasts of the United States, where much research and implementation of oyster reef restoration has occurred, to better define the existing gaps in our understanding of the use of restored oyster reefs for shoreline protection. We find potential disconnects between ecological and engineering functions of reefs. In response, we outline how engineering and ecological principles are used in the design of oyster reef living shorelines and highlight knowledge gaps where an integration of these disciplines will lead to their more effective application. Synthesis and applications . This work highlights the necessary steps to advance the application of oyster reef living shorelines. Importantly, future research should focus on appropriate designs and conditions needed for these structures to effectively protect our coasts from erosion, while supporting a sustainable oyster population, thereby providing actionable nature‐based alternatives for coastal defence to diverse end‐users.

East Coast of Continental United States↗