USGS Science⌕ Search

SEARCH · USGS Science

Results for “Aquatic Ecology”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
USGS2023

Toxic algae in inland waters of the conterminous United States—A review and synthesis

Cyanobacteria are the most common toxigenic algae in inland waters. Their toxins can affect the health of aquatic and terrestrial organisms, including humans. Other algal groups, such as haptophytes (e.g., Prymnesium parvum ) and euglenoids (e.g., Euglena sanguinea ), can also form harmful algal blooms (HABs) whose toxins cause injury to aquatic biota but currently have no known effects on human health. Prymnesium parvum , however, is responsible for some of the worst HAB-related ecological disasters recorded in inland waters. Here, we provide an overview of the primary toxigenic algae found in U.S. inland waters: cyanobacteria (planktonic forms), P. parvum , and E. sanguinea with the objective of describing their similarities and differences in the areas of HAB ecology, algal toxins, and the potential for future range expansion of HABs. A detailed account of bloom habitats and their known associations with land cover and use is provided from the perspective of water quality. This review revealed that salinity may have an influence on inland cyanobacterial blooms and cyanotoxins that had not been fully recognized previously.

Water↗
USGS2006

Integrating human impacts and ecological integrity into a risk-based protocol for conservation planning

Conservation planning aims to protect biodiversity by sustainng the natural physical, chemical, and biological processes within representative ecosystems. Often data to measure these components are inadequate or unavailable. The impact of human activities on ecosystem processes complicates integrity assessments and might alter ecosystem organization at multiple spatial scales. Freshwater conservation targets, such as populations and communities, are influenced by both intrinsic aquatic properties and the surrounding landscape, and locally collected data might not accurately reflect potential impacts. We suggest that changes in five major biotic drivers—energy sources, physical habitat, flow regime, water quality, and biotic interactions—might be used as surrogates to inform conservation planners of the ecological integrity of freshwater ecosystems. Threats to freshwater systems might be evaluated based on their impact to these drivers to provide an overview of potential risk to conservation targets. We developed a risk-based protocol, the Ecological Risk Index (ERI), to identify watersheds with least/most risk to conservation targets. Our protocol combines risk-based components, specifically the frequency and severity of human-induced stressors, with biotic drivers and mappable land- and water-use data to provide a summary of relative risk to watersheds. We illustrate application of our protocol with a case study of the upper Tennessee River basin, USA. Differences in risk patterns among the major drainages in the basin reflect dominant land uses, such as mining and agriculture. A principal components analysis showed that localized, moderately severe threats accounted for most of the threat composition differences among our watersheds. We also found that the relative importance of threats is sensitive to the spatial grain of the analysis. Our case study demonstrates that the ERI is useful for evaluating the frequency and severity of ecosystemwide risk, which can inform local and regional conservation planning.

Tennessee↗
USGS2010

Southeast Regional Assessment Project for the National Climate Change and Wildlife Science Center, U.S. Geological Survey

The Southeastern United States spans a broad range of physiographic settings and maintains exceptionally high levels of faunal diversity. Unfortunately, many of these ecosystems are increasingly under threat due to rapid human development, and management agencies are increasingly aware of the potential effects that climate change will have on these ecosystems. Natural resource managers and conservation planners can be effective at preserving ecosystems in the face of these stressors only if they can adapt current conservation efforts to increase the overall resilience of the system. Climate change, in particular, challenges many of the basic assumptions used by conservation planners and managers. Previous conservation planning efforts identified and prioritized areas for conservation based on the current environmental conditions, such as habitat quality, and assumed that conditions in conservation lands would be largely controlled by management actions (including no action). Climate change, however, will likely alter important system drivers (temperature, precipitation, and sea-level rise) and make it difficult, if not impossible, to maintain recent historic conditions in conservation lands into the future. Climate change will also influence the future conservation potential of non-conservation lands, further complicating conservation planning. Therefore, there is a need to develop and adapt effective conservation strategies to cope with the effects of climate and landscape change on future environmental conditions. Congress recognized this important issue and authorized the U.S. Geological Survey (USGS) National Climate Change and Wildlife Science Center (NCCWSC; http://nccw.usgs.gov/) in the Fiscal Year 2008. The NCCWSC will produce science that will help resource management agencies anticipate and adapt to climate change impacts to fish, wildlife, and their habitats. With the release of Secretarial Order 3289 on September 14, 2009, the mandate of the NCCWSC was expanded to address climate change-related impacts on all Department of the Interior (DOI) resources. The NCCWSC will establish a network of eight DOI Regional Climate Science Centers (RCSCs) that will work with a variety of partners to provide natural resource managers with tools and information that will help them anticipate and adapt conservation planning and design for projected climate change. The forecasting products produced by the RCSCs will aid fish, wildlife, and land managers in designing suitable adaptive management approaches for their programs. The DOI also is developing Landscape Conservation Cooperatives (LCCs) as science and conservation action partnerships at subregional scales. The USGS is working with the Southeast Region of the U.S. Fish and Wildlife Service (FWS) to develop science collaboration between the future Southeast RCSC and future LCCs. The NCCWSC Southeast Regional Assessment Project (SERAP) will begin to develop regional downscaled climate models, land cover change models, regional ecological models, regional watershed models, and other science tools. Models and data produced by SERAP will be used in a collaborative process between the USGS, the FWS (LCCs), State and federal partners, nongovernmental organizations, and academia to produce science at appropriate scales to answer resource management questions. The SERAP will produce an assessment of climate change, and impacts on land cover, ecosystems, and priority species in the region. The predictive tools developed by the SERAP project team will allow end users to better understand potential impacts of climate change and sea level rise on terrestrial and aquatic populations in the Southeastern United States. The SERAP capitalizes on the integration of five existing projects: (1) the Multi-State Conservation Grants Program project "Designing Sustainable Landscapes," (2) the USGS multidisciplinary Science Thrust project "Water Availability for Ecological Needs," (3) the USGS Southeast Pilot Project "Climate Change in the Southeastern U.S. and its Impacts on Bird Distributions and Habitats," (4) a sea-level rise impacts study envisioned jointly with the National Oceanic and Atmospheric Administration (NOAA), and (5) two USGS sea-level rise impact assessment projects that address inundation hazards and provide probabilistic forecasts of coastal geomorphic change. The SERAP will expand on these existing projects and include the following tasks, which were initiated in summer 2009: * Regionally downscaled probabilistic climate-change projections * Integrated coastal assessment * Integrated terrestrial assessment * Multi-resolution assessment of potential climate change effects on biological resources: aquatic and hydrologic dynamics * Optimal conservation strategies to cope with climate change The SERAP seeks to formally integrate these tasks to aid conservation planning and design so that ecosystem management decisions can be optimized for providing desirable outcomes across a range of species and environments. The following chapters detail SERAP's efforts in providing a suite of regional climate, watershed, and landscape-change analyses and develop the interdisciplinary framework required for the biological planning phases of adaptive management and strategic conservation. The planning phase will include the identification of conservation alternatives, development of predictive models and decision support tools, and development of a template to address similar challenges and goals in other regions. The project teams will explore and develop ways to link the various ecological models arising from each component. The SERAP project team also will work closely with members of the LCCs and other partnerships throughout the life of the project to ensure that the objectives of the project meet resources mangers needs in the Southeast.

Open-File Report↗
USGS2009

A macroinvertebrate assessment of Ozark streams located in lead-zinc mining areas of the Viburnum Trend in southeastern Missouri, USA

The Viburnum Trend lead-zinc mining subdistrict is located in the southeast Missouri portion of the Ozark Plateau. In 2003 and 2004, we assessed the ecological effects of mining in several watersheds in the region. We included macroinvertebrate surveys, habitat assessments, and analysis of metals in sediment, pore water, and aquatic biota. Macroinvertebrates were sampled at 21 sites to determine aquatic life impairment status (full, partial, or nonsupport) and relative biotic condition scores. Macroinvertebrate biotic condition scores were significantly correlated with cadmium, nickel, lead, zinc, and specific conductance in 2003 (r = -0.61 to -0.68) and with cadmium, lead, and pore water toxic units in 2004 (r = -0.55 to -0.57). Reference sites were fully supporting of aquatic life and had the lowest metals concentrations and among the highest biotic condition scores in both years. Sites directly downstream from mining and related activities were partially supporting, with biotic condition scores 10% to 58% lower than reference sites. Sites located greater distances downstream from mining activities had intermediate scores and concentrations of metals. Results indicate that elevated concentrations of metals originating from mining activities were the underlying cause of aquatic life impairment in several of the streams studied. There was general concurrence among the adversely affected sites in how the various indicators responded to mining activities during the overall study.

Missouri↗
USGS2018

A distributed pipeline for DIDSON data processing

Technological advances in the field of ecology allow data on ecological systems to be collected at high resolution, both temporally and spatially. Devices such as Dual-frequency Identification Sonar (DIDSON) can be deployed in aquatic environments for extended periods and easily generate several terabytes of underwater surveillance data which may need to be processed multiple times. Due to the large amount of data generated and need for flexibility in processing, a distributed pipeline was constructed for DIDSON data making use of the Hadoop ecosystem. The pipeline is capable of ingesting raw DIDSON data, transforming the acoustic data to images, filtering the images, detecting and extracting motion, and generating feature data for machine learning and classification. All of the tasks in the pipeline can be run in parallel and the framework allows for custom processing. Applications of the pipeline include monitoring migration times, determining the presence of a particular species, estimating population size and other fishery management tasks.

Conference Paper↗
USGS2006

Data Delivery and Mapping Over the Web: National Water-Quality Assessment Data Warehouse

The U.S. Geological Survey began its National Water-Quality Assessment (NAWQA) Program in 1991, systematically collecting chemical, biological, and physical water-quality data from study units (basins) across the Nation. In 1999, the NAWQA Program developed a data warehouse to better facilitate national and regional analysis of data from 36 study units started in 1991 and 1994. Data from 15 study units started in 1997 were added to the warehouse in 2001. The warehouse currently contains and links the following data: -- Chemical concentrations in water, sediment, and aquatic-organism tissues and related quality-control data from the USGS National Water Information System (NWIS), -- Biological data for stream-habitat and ecological-community data on fish, algae, and benthic invertebrates, -- Site, well, and basin information associated with thousands of descriptive variables derived from spatial analysis, like land use, soil, and population density, and -- Daily streamflow and temperature information from NWIS for selected sampling sites.

Fact Sheet↗
USGS2020

Pooling resources across organizations — Multisource water-quality data for the Delaware River Basin

The U.S. Geological Survey (USGS) recently launched a pilot Integrated Water Availability Assessment (IWAA) in the Delaware River Basin to explore, test, and refine systems and processes for assessing water availability for human and ecological uses based on water monitoring data. Water-quality monitoring provides citizens, managers, and scientists with the information needed to evaluate the health of aquatic ecosystems and the safety and availability of water for drinking, agriculture, recreation, and other uses. Many organizations collect water-quality data at various sites and sampling frequencies to meet their assessment needs. The result is multiple individual datasets suitable for the specific organization’s needs that also hold great potential if pooled into a much larger dataset sourced from multiple organizations (multisource data). A multisource dataset increases the value and power of multiple single datasets and expands the breadth and depth of available water-quality data to ultimately increase the number and types of questions that can be answered. This fact sheet describes the process of “harmonizing” water-quality data from multiple organizations and presents a recently developed dataset for surface-water quality in the Delaware River Basin. This harmonized multisource surface-water-quality dataset will serve as a resource for analysis and modeling of surface-water quality to support IWAA efforts in the basin. Furthermore, this harmonization process can be expanded and applied to other regional IWAA basins or applied nationally.

Delaware, Maryland, New York, New Jersey, Pennsylv↗
USGS2020

Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA

The Biological Condition Gradient (BCG) is a conceptual model that describes changes in aquatic communities under increasing levels of anthropogenic stress. The BCG helps decision-makers connect narrative water quality goals (e.g., maintenance of natural structure and function) to quantitative measures of ecological condition by linking index thresholds based on statistical distributions (e.g., percentiles of reference distributions) to expert descriptions of changes in biological condition along disturbance gradients. As a result, the BCG may be more meaningful to managers and the public than indices alone. To develop a BCG model, biological response to stress is divided into 6 levels of condition, represented as changes in biological structure (abundance and diversity of pollution sensitive versus tolerant taxa) and function. We developed benthic macroinvertebrate (BMI) and algal BCG models for California perennial wadeable streams to support interpretation of percentiles of reference-based thresholds for bioassessment indices (i.e., the California Stream Condition Index [CSCI] for BMI and the Algal Stream Condition Index [ASCI] for diatoms and soft-bodied algae). Two panels (one of BMI ecologists and the other of algal ecologists) each calibrated a general BCG model to California wadeable streams by first assigning taxa to specific tolerance and sensitivity attributes, and then independently assigning test samples (264 BMI and 248 algae samples) to BCG Levels 1–6. Consensus on the assignments was developed within each assemblage panel using a modified Delphi method. Panels then developed detailed narratives of changes in BMI and algal taxa that correspond to the 6 BCG levels. Consensus among experts was high, with 81% and 82% expert agreement within 0.5 units of assigned BCG level for BMIs and algae, respectively. According to both BCG models, the 10th percentiles index scores at reference sites corresponded to a BCG Level 3, suggesting that this type of threshold would protect against moderate changes in structure and function while allowing loss of some sensitive taxa. The BCG provides a framework to interpret changes in aquatic biological condition along a gradient of stress. The resulting relationship between index scores and BCG levels and narratives can help decision-makers select thresholds and communicate how these values protect aquatic life use goals.

California↗
USGS2015

Management and the conservation of freshwater ecosystems

Riparian areas are the terrestrial environment adjacent to water that both influences and is influenced by the aquatic feature (Gregory et al ., 1991; Naiman et al ., 2010). Riparian areas along streams provide shade, sources of wood and organic matter, contribute to bank stability, filter sediments, take up excess nutrients from groundwater inputs, and other key processes that protect freshwaters (e.g. Naiman et al ., 2010; Richardson & Danehy, 2007; Figure 9.1). Riparian areas also increase biodiversity through habitat complexity and close juxtaposition of aquatic and terrestrial environments (Quinn et al ., 2004; Naiman et al ., 2010). Alterations to riparian areas, despite their small area relative to the landscape, have disproportionate effects on habitats and fish communities (Naiman et al ., 2010; Wipfli & Baxter, 2010). Key habitat losses and alterations are derived from modification of riparian areas by reducing instream habitat complexity (Bilby & Ward, 1989; Fausch & Northcote, 1992; Naiman et al ., 2010), diminishing the productive basis of freshwater food webs (Belsky et al ., 1999; Quinn et al ., 2004), increasing nutrient, contaminant and sediment intrusion (Muscutt et al ., 1993; Daniels & Gilliam, 1996; Nguyen et al ., 1998; Waters, 1999). Riparian and freshwater ecosystems are typically tightly coupled, especially in their natural states, and the linkages that couple them frequently exert strong influence on their associated invertebrate and fish fauna (e.g. Gregory et al ., 1991; Naiman et al ., 2010). Riparian habitats, and the condition of these habitats, further plays a key role in the ecology of these fresh waters, influencing critical processes such as water, nutrient and sediment delivery and dynamics; prey resources for fish and other consumers, and other organic materials exchanged between aquatic and terrestrial habitats (Nakano et al ., 1999; Naiman et al ., 2010); light and water temperature dynamics that in turn affect food web processes and fish metabolism and growth; aquatic physical habitat (wood); and terrestrial consumers that prey upon fishes (Bisson & Bilby, 1998; Naiman et al ., 2010; Wipfli & Baxter, 2010). These processes in turn directly or indirectly influence fishes in freshwater systems (Wang et al ., 2001; Pusey & Arthington, 2003; Allan, 2004; Richardson et al ., 2010a).

Book chapter↗
USGS2005

Aquatic habitat mapping with an acoustic doppler current profiler: Considerations for data quality

When mounted on a boat or other moving platform, acoustic Doppler current profilers (ADCPs) can be used to map a wide range of ecologically significant phenomena, including measures of fluid shear, turbulence, vorticity, and near-bed sediment transport. However, the instrument movement necessary for mapping applications can generate significant errors, many of which have not been inadequately described. This report focuses on the mechanisms by which moving-platform errors are generated, and quantifies their magnitudes under typical habitat-mapping conditions. The potential for velocity errors caused by mis-alignment of the instrument?s internal compass are widely recognized, but has not previously been quantified for moving instruments. Numerical analyses show that even relatively minor compass mis-alignments can produce significant velocity errors, depending on the ratio of absolute instrument velocity to the target velocity and on the relative directions of instrument and target motion. A maximum absolute instrument velocity of about 1 m/s is recommended for most mapping applications. Lower velocities are appropriate when making bed velocity measurements, an emerging application that makes use of ADCP bottom-tracking to measure the velocity of sediment particles at the bed. The mechanisms by which heterogeneities in the flow velocity field generate horizontal velocities errors are also quantified, and some basic limitations in the effectiveness of standard error-detection criteria for identifying these errors are described. Bed velocity measurements may be particularly vulnerable to errors caused by spatial variability in the sediment transport field.

Open-File Report↗
USGS2009

Predicting bed shear stress and its role in sediment dynamics and restoration potential of the Everglades and other vegetated flow systems

Entrainment of sediment by flowing water affects topography, habitat suitability, and nutrient cycling in vegetated floodplains and wetlands, impacting ecosystem evolution and the success of restoration projects. Nonetheless, restoration managers lack simple decision-support tools for predicting shear stresses and sediment redistribution potential in different vegetation communities. Using a field-validated numerical model, we developed state-space diagrams that provide these predictions over a range of water-surface slopes, depths, and associated velocities in Everglades ridge and slough vegetation communities. Diminished bed shear stresses and a consequent decrease in bed sediment redistribution are hypothesized causes of a recent reduction in the topographic and vegetation heterogeneity of this ecosystem. Results confirmed the inability of present-day flows to entrain bed sediment. Further, our diagrams showed bed shear stresses to be highly sensitive to emergent vegetation density and water-surface slope but less sensitive to water depth and periphyton or floating vegetation abundance. These findings suggested that instituting a pulsing flow regime could be the most effective means to restore sediment redistribution to the Everglades. However, pulsing flows will not be sufficient to erode sediment from sloughs with abundant spikerush, unless spikerush density first decreases by natural or managed processes. Our methods provide a novel tool for identifying restoration parameters and performance measures in many types of vegetated aquatic environments where sediment erosion and deposition are involved.

Ecological Engineering↗
USGS2011

Comparing isotope signatures of prey fish: does gut removal affect δ13C or δ15N?

Stable isotope analysis is a quick and inexpensive method to monitor the effects of food web changes on aquatic communities. Traditionally, whole specimens have been used when determining isotope composition of prey fish or age-0 recreational fishes. However, gut contents of prey fish could potentially alter isotope composition of the specimen, especially when recent foraging has taken place or when the gut contains non-assimilated material that would normally pass through fishes undigested. To assess the impacts of gut content on prey fish isotope signatures, we examined the differences in isotopic variation of five prey fish species using whole fish, whole fish with the gut contents removed, and dorsal muscle only. We found significant differences in both δ 15 N and δ 13 C between the three tissue treatments. In most cases, muscle tissue was enriched compared to whole specimens or gut-removed specimens. Moreover, differences in mean δ 15 N within a species were up to 2‰ among treatments. This would result in a change of over half a trophic position (TP) based on a 3.4‰ increase per trophic level. However, there were no apparent relationships between tissue isotope values in fish with increased gut fullness (more prey tissue present). We suggest that muscle tissue should be used as the standard tissue for determining isotope composition of prey fish or age-0 recreational fishes, especially when determining enrichment for mixing models, calculating TP, or constructing aquatic food webs.

Journal of Freshwater Ecology↗
USGS2015

Behavioral evidence for a role of chemoreception during reproduction in lake trout

Chemoreception is hypothesized to influence spawning site selection, mate search, and synchronization of gamete release in chars ( Salvelinus spp.), but behavioral evidence is generally lacking. Here, we provide a survey of the behavioral responses of reproductive male and female lake trout ( Salvelinus namaycush ) to natural conspecific chemosensory stimuli. A flow-through laboratory assay with side-by-side artificial spawning reefs was used to evaluate behavioral preferences of spawning-phase males and females for chemosensory stimuli from juveniles and from spawning-phase males and females. Males and females preferred male and juvenile stimuli over no stimuli, but only had weak preferences for female stimuli. Only females had a preference for male over juvenile stimuli when given a direct choice between the two. The unexpected observation of male attraction to male stimuli, even when offered female stimuli, indicates a fundamental difference from the existing models of chemical communication in fishes. We discuss our results from the perspectives of prespawning aggregation, mate evaluation, and spawning synchronization. Identification of specific components of the stimuli will allow confirmation of the function and may have management implications for native and invasive populations of lake trout that are ecologically and economically important.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1997

Conditions for the return and simulation of the recovery of burrowing mayflies in western Lake Erie

In the 1950s, burrowing mayflies, Hexagenia spp. ( H. limbata and H. rigida ), were virtually eliminated from the western basin of Lake Erie (a 3300 km 2 area) because of eutrophication and pollution. We develop and present a deterministic model for the recolonization of the western basin by Hexagenia to pre-1953 densities. The model was based on the logistic equation describing the population growth of Hexagenia and a presumed competitor, Chironomus (dipteran larvae). Other parameters (immigration, low oxygen, toxic sediments, competition with Chironomus, and fish predation) were then individually added to the logistic model to determine their effect at different growth rates. The logistic model alone predicts 10–41 yr for Hexagenia to recolonize western Lake Erie. Immigration reduced the recolonization time by 2–17 yr. One low-oxygen event during the first 20 yr increased recovery time by 5–17 yr. Contaminated sediments added 5–11 yr to the recolonization time. Competition with Chironomus added 8–19 yr to recovery. Fish predators added 4–47 yr to the time required for recolonization. The full model predicted 48–81 yr for Hexagenia to reach a carrying capacity of ≈350 nymphs/m 2 , or not until around the year 2038 if the model is started in 1990. The model was verified by changing model parameters to those present in 1970, beginning the model in 1970 and running it through 1990. Predicted densities overlapped almost completely with actual estimated densities of Hexagenia nymphs present in the western basin in Lake Erie in 1990. The model suggests that recovery of large aquatic ecosystems may lag substantially behind remediation efforts.

Michigan, Ohio, Ontario↗
USGS2001

The introduction of nonnative fish into wilderness lakes: Good intentions, conflicting mandates, and unintended consequences

Because they have the potential to provide the best remaining standards of relatively unmodified landscapes, protected areas in North America (such as wilderness areas and national parks) have tremendous ecological and scientific value (Cole and Landres 1996). Although the montane ecosystems of western North America are particularly well represented in this complex of protected lands, aquatic habitats within these protected areas are often subject to management practices that are inconsistent with the goal of maintaining natural processes. The most prevalent of these practices is the introduction of salmonid fishes (such as trout) into historically fishless ecosystems to create recreational fisheries.

Ecosystems↗
USGS2018

Differing modes of biotic connectivity within freshwater ecosystem mosaics

We describe a collection of aquatic and wetland habitats in an inland landscape, and their occurrence within a terrestrial matrix, as a “freshwater ecosystem mosaic” (FEM). Aquatic and wetland habitats in any FEM can vary widely, from permanently ponded lakes, to ephemerally ponded wetlands, to groundwater‐fed springs, to flowing rivers and streams. The terrestrial matrix can also vary, including in its influence on flows of energy, materials, and organisms among ecosystems. Biota occurring in a specific region are adapted to the unique opportunities and challenges presented by spatial and temporal patterns of habitat types inherent to each FEM. To persist in any given landscape, most species move to recolonize habitats and maintain mixtures of genetic materials. Species also connect habitats through time if they possess needed morphological, physiological, or behavioral traits to persist in a habitat through periods of unfavorable environmental conditions. By examining key spatial and temporal patterns underlying FEMs, and species‐specific adaptations to these patterns, a better understanding of the structural and functional connectivity of a landscape can be obtained. Fully including aquatic, wetland, and terrestrial habitats in FEMs facilitates adoption of the next generation of individual‐based models that integrate the principles of population, community, and ecosystem ecology.

Journal of the American Water Resources Associatio↗
USGS2013

Wyoming Basin Rapid Ecoregional Assessment

The overall goal of the Wyoming Basin Rapid Ecoregional Assessment (REA) is to provide information that supports regional planning and analysis for the management of ecological resources. The REA provides an assessment of baseline ecological conditions, an evaluation of current risks from drivers of ecosystem change (including energy development, fire, and invasive species), and a predictive capacity for evaluating future risks (including climate change). Additionally, the REA may be used for identifying priority areas for conservation or restoration and for assessing cumulative effects of multiple land uses. The Wyoming Basin REA will address Management Questions developed by the Bureau of Land Management and other agency partners for 8 major biomes and 19 species or species assemblages. The maps developed for addressing Management Questions will be integrated into overall maps of landscape-level ecological values and risks. The maps can be used to address the goals of the REA at a number of levels: for individual species, species assemblages, aquatic and terrestrial systems, and for the entire ecoregion. This allows flexibility in how the products of the REA are compiled to inform planning and management actions across a broad range of spatial scales.

Colorado;Idaho;Montana;Utah;Wyoming↗
USGS2023

Nearshore subtidal community response during and after sediment disturbance associated with dam removal

Dam removal is used increasingly to restore aquatic ecosystems and remove unnecessary or high-risk infrastructure. As the number of removals increases, there is a growing understanding about the hydrologic, geomorphic, and ecological responses to these removals. Most dam removal studies, however, focus on river and watershed responses to dam removal. The removal of two dams on the Elwha River provided a unique opportunity to characterize the response of nearshore (coastal) ecosystems. We conducted SCUBA surveys between 2011 and 2022 to quantify trajectories of change in a nearshore ecosystem during and after dam removal. We focused on the degree to which the abundances of kelp, benthic invertebrates, and fish changed in response to patterns of sediment fluxes during and after dam removal. Our findings point to two pathways of response depending on the disturbance mechanism and species type. Sites with persistent sediment deposition were characterized by wholesale community changes that did not recover to a before dam removal condition. Instead, the sites were colonized by new species that were largely absent prior to dam removal. Sites that experienced high turbidity but lacked persistent seafloor deposition were primarily characterized by a reduction in the abundance of kelp and other algae during dam removal and a rapid recovery after sediment flux to the nearshore declined. Dam removal influences on invertebrates and fish at these sites were more variable, benefiting some species and disadvantaging others. In addition to dam removal, sea star wasting syndrome and a marine heatwave exerted distinct controls on subtidal communities during the same period. The loss of the predatory sea star Pycnopodia helianthoides was associated with gains in some of its prey species, and kelp community changes reflected regional trends in ocean temperature and kelp abundance. The results presented here have important implications for understanding the response of marine ecosystems to future dam removals and similar sediment perturbation events.

Washington↗