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At least 361 records · Page 20Linked to original sources
USGS2012

Simulation of groundwater and surface-water interaction and effects of pumping in a complex glacial-sediment aquifer, east central Massachusetts

The effects of groundwater pumping on surface-water features were evaluated by use of a numerical groundwater model developed for a complex glacial-sediment aquifer in northeastern Framingham, Massachusetts, and parts of surrounding towns. The aquifer is composed of sand, gravel, silt, and clay glacial-fill sediments up to 270 feet thick over an irregular fractured bedrock surface. Surface-water bodies, including Cochituate Brook, the Sudbury River, Lake Cochituate, Dudley Pond, and adjoining wetlands, are in hydraulic connection with the aquifer and can be affected by groundwater withdrawals. Groundwater and surface-water interaction was simulated with MODFLOW-NWT under current conditions and a variety of hypothetical pumping conditions. Simulations of hypothetical pumping at reactivated water supply wells indicate that captured groundwater would decrease baseflow to the Sudbury River and induce recharge from Lake Cochituate. Under constant (steady-state) pumping, induced groundwater recharge from Lake Cochituate was equal to about 32 percent of the simulated pumping rate, and flow downstream in the Sudbury River decreased at the same rate as pumping. However, surface water responded quickly to pumping stresses. When pumping was simulated for 1 month and then stopped, streamflow depletions decreased by about 80 percent within 2 months and by about 90 percent within about 4 months. The fast surface water response to groundwater pumping offers the potential to substantially reduce streamflow depletions during periods of low flow, which are of greatest concern to the ecological integrity of the river. Results indicate that streamflow depletion during September, typically the month of lowest flow, can be reduced by 29 percent by lowering the maximum pumping rates to near zero during September. Lowering pumping rates for 3 months (July through September) reduces streamflow depletion during September by 79 percent as compared to constant pumping. These results demonstrate that a seasonal or streamflow-based groundwater pumping schedule can reduce the effects of pumping during periods of low flow.

Massachusetts↗
USGS2020

The Everglades Depth Estimation Network (EDEN) surface-water interpolation model, version 3

The Everglades Depth Estimation Network (EDEN) is an integrated network of water-level gages, interpolation models that estimate daily water-level data at ungaged locations, and applications that generate derived hydrologic data across the freshwater part of the Greater Everglades landscape. Version 3 (V3) of the EDEN interpolation surface-water model is the most recent update, replacing the version 2 (V2) model released in 2011. The primary revision for the V3 model is the switch to the R programming language to create a more efficient and portable EDEN code relative to V2, without reliance on proprietary software. Using R, the interpolation script runs over 10 times faster and is more easily updated, for example, to accommodate changes in the gage network or to incorporate R software updates. Additional revisions made for the V3 model include updates to the interpolation model, the gage network, and groundwater-level estimations. The EDEN model domain in the Greater Everglades and Big Cypress National Preserve is divided into subdomains that are based on hydrologic boundaries. In the V3 model, the number of subdomains was increased from five to eight, which allows hydrologic boundaries, such as levees and canals, to be better represented in the interpolation scheme. Five pseudogages were added to constrain the water-level surface at subdomain boundaries. Changes made to the water-level gage network between the implementation of the V2 and V3 models are incorporated, and groundwater-level estimations are added, which are important information for hydrologic and ecological studies. Summary model performance statistics indicate similar accuracy in water-level surfaces generated by the V3 and V2 models, with a root mean square error of 4.78 centimeters for both interpolation models against independent water-level measurements. Providing stability and continuity for the EDEN user community, the V3 model closely replicates the V2 model, with a root mean square difference of 3.87 centimeters for interpolated surfaces from April 1, 2014, to March 31, 2018. The additional groundwater levels provide a realistic estimate of the saturated groundwater surface continuous with the surface-water surface for Water Conservation Areas 2A and 2B from 2000 to 2011. This continuous surface is a more accurate estimation of the spatial distribution of water in the hydrologic system than before, providing needed information for ecological studies in areas where depth to water table affects habitats. Development of the EDEN V3 model advances the tools available to scientists and resource managers for guiding large-scale field operations, describing hydrologic changes, and supporting biological and ecological assessments.

Florida↗
USGS2016

Macroinvertebrate and diatom metrics as indicators of water-quality conditions in connected depression wetlands in the Mississippi Alluvial Plain

Methods for assessing wetland conditions must be established so wetlands can be monitored and ecological services can be protected. We evaluated biological indices compiled from macroinvertebrate and diatom metrics developed primarily for streams to assess their ability to indicate water quality in connected depression wetlands. We collected water-quality and biological samples at 24 connected depressions dominated by water tupelo ( Nyssa aquatica ) or bald cypress ( Taxodium distichum ) (water depths = 0.5–1.0 m). Water quality of the least-disturbed connected depressions was characteristic of swamps in the southeastern USA, which tend to have low specific conductance, nutrient concentrations, and pH. We compared 162 macroinvertebrate metrics and 123 diatom metrics with a water-quality disturbance gradient. For most metrics, we evaluated richness, % richness, abundance, and % relative abundance values. Three of the 4 macroinvertebrate metrics that were most beneficial for identifying disturbance in connected depressions decreased along the disturbance gradient even though they normally increase relative to stream disturbance. The negative relationship to disturbance of some taxa (e.g., dipterans, mollusks, and crustaceans) that are considered tolerant in streams suggests that the tolerance scale for some macroinvertebrates can differ markedly between streams and wetlands. Three of the 4 metrics chosen for the diatom index reflected published tolerances or fit the usual perception of metric response to disturbance. Both biological indices may be useful in connected depressions elsewhere in the Mississippi Alluvial Plain Ecoregion and could have application in other wetland types. Given the paradoxical relationship of some macroinvertebrate metrics to dissolved O 2 (DO), we suggest that the diatom metrics may be easier to interpret and defend for wetlands with low DO concentrations in least-disturbed conditions.

Arkansas↗
USGS2004

Characterization of Lake Michigan coastal lakes using zooplankton assemblages

Zooplankton assemblages and water quality were examined bi-weekly from 17 April to 19 October 1998 in 11 northeastern Lake Michigan coastal lakes of similar origin but varied in trophic status and limnological condition. All lakes were within or adjacent to Sleeping Bear Dunes National Lakeshore, Michigan. Zooplankton (principally microcrustaceans and rotifers) from triplicate Wisconsin net (80 I?m) vertical tows taken at each lake's deepest location were analyzed. Oxygen-temperature-pH-specific conductivity profiles and surface water quality were concurrently measured. Bray-Curtis similarity analysis showed small variations among sample replicates but large temporal differences. The potential use of zooplankton communities for environmental lake comparisons was evaluated by means of BIOENV (Primer 5.1) and principal component analyses. Zooplankton analyzed at the lowest identified taxonomic level yielded greatest sensitivity to limnological variation. Taxonomic and ecological aggregations of zooplankton data performed comparably, but less well than the finest taxonomic analysis. Secchi depth, chlorophyll a, and sulfate concentrations combined to give the best correlation with patterns of variation in the zooplankton data set. Principal component analysis of these variables revealed trophic status as the most influential major limnological gradient among the study lakes. Overall, zooplankton abundance was an excellent indicator of variation in trophic status.

Ecological Indicators↗
USGS2019

Effects of urban multi-stressors on three stream biotic assemblages

During 2014, the U.S. Geological Survey (USGS) National Water-Quality Assessment(NAWQA) project assessed stream quality in 75 streams across an urban disturbance gradient within the Piedmont ecoregion of southeastern United States. Our objectives were to identify primary instream stressors affecting algal, macroinvertebrate and fish assemblages in wadeable streams. Biotic communities were surveyed once at each site, and various instream stressors were measured during a 4-week index period preceding the ecological sampling. The measured stressors included nutrients; contaminants in water, passive samplers, and sediment; instream habitat; and flow variability. All nine boosted regression tree models – three for each of algae, invertebrates, and fish – had cross-validation R 2 (CV R 2 ) values of 0.41 or above, and an invertebrate model had the highest CV R 2 of 0.65. At least one contaminant metric was important in every model, and minimum daytime dissolved oxygen (DO), nutrients, and flow alteration were important explanatory variables in many of the models. Physical habitat metrics such as sediment substrate were only moderately important. Flow alteration metrics were useful factors in eight of the nine models. Total phosphorus, acetanilide herbicides and flow (time since last peak) were important in all three algal models, whereas insecticide metrics (especially those representing fipronil and imidacloprid) were dominant in the invertebrate models. DO values below approximately 7 mg/L corresponded to a strong decrease in sensitive taxa or an increase in tolerant taxa. DO also showed strong interactions with other variables, particularly contaminants and sediment, where the combined effect of low DO and elevated contaminants increased the impact on the biota more than each variable individually. Contaminants and flow alteration were strongly correlated to urbanization, indicating the importance of urbanization to ecological stream condition in the region.

Science of the Total Environment↗
USGS2026

Global change and threats to waterbirds in the Asian flyways

Avian migration represents one of nature’s most spectacular phenomena, providing critical ecological services and acting as an indicator of environmental change. Flyways are geographical ranges through which migrating bird species move, and the flyway concept has been used to identify countries that share species to highlight their collective responsibility for conservation. Of the nine recognized global waterbird flyways, the Central Asian Flyway (CAF) and the East Asian–Australasian Flyway (EAAF) are among the most important areas in Eurasia, supporting millions of waterbirds across a vast network of habitats. We proposed this special issue in Avian Research entitled “Global Change and Threats to Waterbirds in the Asian Flyways” to synthesize recent findings from 12 papers covering a wide range of topics. The CAF stretches from the Siberian tundra through Central Asia including Mongolia, the Qinghai-Tibet Plateau, the Trans-Caucasus, and the Himalayas, extending south to the Indian subcontinent and parts of the Middle East. The EAAF spans eastern Siberia and Alaska to Southeast Asia, Australia, and New Zealand, including China, Japan, the Korean Peninsula, and the Russian Far East. These two flyways include 47 countries comprising critical wetlands, river basins, and coastal areas, which are vital breeding, stopover, and wintering grounds for waterbirds. Seasonal migration in these flyways is fundamentally influenced by climate and weather conditions, land cover dynamics, and anthropogenic activities, and contributes significantly to ecological processes such as pest control, nutrient cycling, and organism dispersal. However, migratory waterbirds and their habitats are undergoing enormous challenges. Changes in climate, habitat availability and connectivity, and human activities are altering the phenology, distribution, population dynamics, and health of the migratory bird populations. As migratory waterbirds travel across international boundaries, understanding their movements and responses to environmental change requires collaborative, cross-border research efforts that promote knowledge sharing and interdisciplinary approaches.

Avian Research↗
USGS2026

Severity and certainty metric for kelp stressors: A tool for research, management, and conservation

Foundation species face multiple threats, and many are in decline worldwide. Kelps are no exception, with declines documented throughout their range. Stressors such as warming, eutrophication, and reduced water quality—often linked to human activities—are well recognized, yet their relative severity and certainty have not been systematically evaluated. Such a framework may aid scientific, regulatory, and conservation organizations in prioritizing actions and decision making. Here we build on a conceptual model of stressors to kelp in the Salish Sea by rating stressor severity and scientific certainty. We convened a panel of regional kelp experts to perform the rating exercise for two canopy taxa, Nereocystis luetkeana and Macrocystis tenuifolia , as well as a grouping for understory species, including both the sporophyte (adult) and gametophyte (juvenile) life stages for these algae. Our process produced a rich dataset which can be separated by stressor, taxa, and life stage allowing for broad applications. The panel identified temperature, low nutrients, and substrate change/benthic sedimentation as the most severe stressors to kelp, with relatively high certainty for most taxa. Certainty scores were relatively high for Nereocystis and Macrocystis sporophytes but were considerably lower for understory species and the gametophyte life stage, for most stressors, highlighting research gaps. Our data set could be applied for management prioritization, setting ecological baselines, and spatial modeling exercises. We encourage scientific, regulatory, and conservation organizations to consider both our data and our process when evaluating their needs. As foundation species continue to face threats, exercises such as this can provide scientists and managers with actionable indices that support strategies to stem degradation.

Ecological Indicators↗
USGS2020

Cottonwoods, water, and people-Integrating analysis of tree rings with observations of elders from the Eastern Shoshone and Northern Arapaho Tribes of the Wind River Reservation, Wyoming

We assessed the history of flow and riparian ecosystem change along the Wind River using cottonwood tree-ring data, streamgage records, historical temperature and precipitation data, drought indices, and local observations and Traditional Ecological Knowledge from elders of the Eastern Shoshone and Northern Arapaho Tribes of the Wind River Reservation, Wyoming. This assessment identified impacts that have occurred to riparian resources of concern to the Tribes, which will assist in prioritizing drought planning efforts. Impacts included reduced abundance, reduced regeneration, and increased mortality in cottonwoods ( Populus deltoides and P. angustifolia ); an increase in invasive species, especially Russian olive ( Elaeagnus angustifolia ), that are gradually replacing cottonwoods and other native woody plants; decreased abundance of native and culturally important plants; reduced abundance of culturally important fish; reduced volume and changes to the timing of flows; and changes in river course. This assessment documented the biophysical and social factors that have contributed to riparian ecosystem change and to reduced water availability and flows, including agricultural diversion, drought, and fire. Cottonwoods along the Wind River are as much as 300 years old. By relating tree-ring width to recorded streamflows, we were able to reconstruct streamflows confidently back to the 1850s and speculatively back to the mid-1700s. Extending the historical record of streamflows allows for a more-complete understanding of hydroclimatic variability and provides a foundation for developing preparedness and response strategies for drought management. Ring width of cottonwood trees at the Boysen Site was more strongly correlated to river flow than to local precipitation or temperature, indicating that growth of trees is controlled more by montane snowmelt than by local weather. Therefore, tree rings are a better indicator of water supply than of the local conditions controlling water demand. The extended flow record from tree rings revealed the occurrence of a major period of low flow from 1870 to 1910 that was not evident in the shorter instrumental records of flow and weather. Information from tree rings, streamflow measurements, drought indices, and elder observations all suggest that the early 2000s drought was the most severe, sustained drought in the last century. Our results illustrate how drought is experienced in different ways across locations and sectors, which underscores the importance of using multiple indicators for drought management. These results will contribute to ongoing assessment, monitoring, and planning efforts at the Wind River Reservation.

Wyoming↗
USGS2008

Prioritizing conservation effort through the use of biological soil crusts as ecosystem function indicators in an arid region

Conservation prioritization usually focuses on conservation of rare species or biodiversity, rather than ecological processes. This is partially due to a lack of informative indicators of ecosystem function. Biological soil crusts (BSCs) trap and retain soil and water resources in arid ecosystems and function as major carbon and nitrogen fixers; thus, they may be informative indicators of ecosystem function. We created spatial models of multiple indicators of the diversity and function of BSCs (species richness, evenness, functional diversity, functional redundancy, number of rare species, number of habitat specialists, nitrogen and carbon fixation indices, soil stabilization, and surface roughening) for the 800,000-ha Grand Staircase-Escalante National Monument (Utah, U.S.A.). We then combined the indicators into a single BSC function map and a single BSC biodiversity map (2 alternative types of conservation value) with an unweighted averaging procedure and a weighted procedure derived from validations performance. We also modeled potential degradation with data from a rangeland assessment survey. To determine which areas on the landscape were the highest conservation priorities, we overlaid the function- and diversity-based conservation-value layers on the potential degradation layer. Different methods for ascribing conservation-value and conservation-priority layers all yielded strikingly similar results (r = 0.89-0.99), which suggests that in this case biodiversity and function can be conserved simultaneously. We believe BSCs can be used as indicators of ecosystem function in concert with other indicators (such as plant-community properties) and that such information can be used to prioritize conservation effort in drylands. ?? 2008 Society for Conservation Biology.

Conservation Biology↗
USGS2026

Quantifying avian resilience to habitat change to support conservation decision-making

Habitat loss and degradation are two of the main drivers of contemporary avian population declines. Wildlife managers are increasingly advocating for tools that provide decision support to set priorities for restoration or conservation efficiently. We demonstrate how to derive two species-specific management and resilience metrics: the greatest management impact point (GMIP) and the ecological resilience threshold (RT). The GMIP indicates the amount of environmental change in a landscape where habitat improvements are expected to have the greatest impact on species’ occurrence. The RT represents the amount of environmental change in a landscape that a species can tolerate before the steepest change in occupancy is expected to begin. We estimate species-specific metrics using the amount of uncharacteristic exotic vegetation as an index of environmental change, and demonstrate how multispecies patterns may suggest potential management strategies. We estimated occupancy models using 5 years of multispecies avian detection data from the Integrated Monitoring in Bird Conservation Regions program in the State of Utah, USA (hereafter, Utah). Based on the estimated relationship between species’ occupancy and amounts of uncharacteristic exotic vegetation, we derive RT and GMIP scores for 61 species breeding in Utah. We found wide interspecific variation in resilience to amounts of exotic vegetation, with species generally clustering at extreme values. Our results demonstrate that birds in Utah appear more resilient to amounts of uncharacteristic exotic vegetation at coarser spatial resolution, showing greater variance and lower average RTs at finer spatial resolution. Species that are not fully resilient to the range of uncharacteristic exotic vegetation observed in this study are expected to respond most strongly, on average, to management actions in landscapes with high levels of exotic vegetation; however, early detection and rapid response is likely the most effective strategy. Quantified across many species, these metrics can be used to identify and prioritize landscapes where current environmental conditions could be maintained to avoid the greatest species’ declines, or which maximize expected biodiversity returns on investment in environmental restoration. Managers can consider either focal species’ resilience for tailored conservation planning or summarize species resilience to create efficient management plans that maximize outcomes for multiple species.

Utah↗
USGS2015

Trends and natural variability of North American spring onset as evaluated by a new gridded dataset of spring indices

Climate change is expected to modify the timing of seasonal transitions this century, impacting wildlife migrations, ecosystem function, and agricultural activity. Tracking seasonal transitions in a consistent manner across space and through time requires indices that can be used for monitoring and managing biophysical and ecological systems during the coming decades. Here a new gridded dataset of spring indices is described and used to understand interannual, decadal, and secular trends across the coterminous United States. This dataset is derived from daily interpolated meteorological data, and the results are compared with historical station data to ensure the trends and variations are robust. Regional trends in the first leaf index range from 20.8 to 21.6 days decade21, while first bloom index trends are between20.4 and 21.2 for most regions. However, these trends are modulated by interannual to multidecadal variations, which are substantial throughout the regions considered here. These findings emphasize the important role large-scale climate modes of variability play in modulating spring onset on interannual to multidecadal time scales. Finally, there is some potential for successful subseasonal forecasts of spring onset, as indices from most regions are significantly correlated with antecedent large-scale modes of variability.

Journal of Climate↗
USGS2019

Surface fire to Crown Fire: Fire history in the Taos Valley watersheds, New Mexico, USA

Tree-ring fire scars, tree ages, historical photographs, and historical surveys indicate that, for centuries, fire played different ecological roles across gradients of elevation, forest, and fire regimes in the Taos Valley Watersheds. Historical fire regimes collapsed across the three watersheds by 1899, leaving all sites without fire for at least 119 years. Historical photographs and quaking aspen (Populus tremuloides Michx.) ages indicate that a high-severity fire historically burned at multiple high-elevation subalpine plots in today’s Village of Taos Ski Valley, with large high-severity patches (>640 ha). Low-severity, frequent (9–29-year median interval) surface fires burned on the south aspects in nearby lower elevation dry conifer forests in all watersheds. Fires were associated with drought during the fire year. Widespread fires commonly burned synchronously in multiple watersheds during more severe drought years, preceded by wet years, including fire in all three watersheds in 1664, 1715, and 1842. In contrast, recent local “large” wildfires have only burned within single watersheds and may not be considered large in a historical context. Management to promote repeated low-severity fires and the associated open stand structures is within the historical range of variability in the dry conifer forests of these watersheds. In the high-elevation, subalpine forests, different management approaches are needed, which balance ecological and socioeconomic values while providing public safety.

New Mexico↗
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↗
USGS2019

Amphibian monitoring in hardwood forests: Optimizing methods for contaminant‐based compensatory restorations

Amphibians such as frogs, toads, and salamanders provide important services in aquatic and terrestrial ecosystems and have been proposed as useful indicators of progress and success for ecological restoration projects. Limited guidance is available, however, on the costs and benefits of different amphibian monitoring techniques that might be applied to sites restored in compensation for contaminant injury. We used a variety of methods to document the amphibian communities present at 4 restored bottomland hardwood sites in Indiana, USA, and to compare the information return and cost of each method. For 1 method—automated recording units—we also modeled the effect of varying levels of sampling effort on the number of species detected, using sample-based rarefaction and Bayesian nonlinear (Michaelis–Menten) mixed effects models. We detected 13 amphibian species across the restored sites, including 2 species of conservation concern in Indiana—northern leopard frogs ( Lithobates pipiens ) and Blanchard's cricket frogs ( Acris blanchardi ). Sites across a range of restoration ages demonstrated encouraging returns of amphibian communities. Although more mature sites showed greater species richness, recently restored sites still provided important habitat for amphibians, including species of conservation concern. Among the 4 methods compared, amphibian rapid assessment yielded the highest number of species detected and the greatest catch per unit effort, with the lowest per-site cost. Our analysis of level-of-effort effects in the rarefied acoustic data found that number of nights sampled was a better predictor of observed species richness than the number of hours sampled within a night or minutes sampled within an hour. These data will assist restoration practitioners in selecting amphibian monitoring methods appropriate for their site characteristics and budget.

Indiana↗
USGS2014

Using scenario planning to evaluate the impacts of climate change on wildlife populations and communities in the Florida Everglades

It is uncertain how climate change will impact hydrologic drivers of wildlife population dynamics in freshwater wetlands of the Florida Everglades, or how to accommodate this uncertainty in restoration decisions. Using projections of climate scenarios for the year 2060, we evaluated how several possible futures could affect wildlife populations (wading birds, fish, alligators, native apple snails, amphibians, threatened and invasive species) across the Everglades landscape and inform planning already underway. We used data collected from prior research and monitoring to parameterize our wildlife population models. Hydrologic data were simulated using a spatially explicit, regional-scale model. Our scenario evaluations show that expected changes in temperature, precipitation, and sea level could significantly alter important ecological functions. All of our wildlife indicators were negatively affected by scenarios with less rainfall and more evapotranspiration. Under such scenarios, habitat suitability was substantially reduced for iconic animals such as wading birds and alligators. Conversely, the increased rainfall scenario benefited aquatic prey productivity and apex predators. Cascading impacts on non-native species is speculative, but increasing temperatures could increase the time between cold events that currently limit expansion and abundance of non-native fishes, amphibians, and reptiles with natural ranges in the tropics. This scenario planning framework underscored the benefits of proceeding with Everglades restoration plans that capture and clean more freshwater with the potential to mitigate rainfall loss and postpone impacts of sea level rise.

Florida↗
USGS2023

Towards a better future for biodiversity and people: Modelling Nature Futures

The Nature Futures Framework (NFF) is a heuristic tool for co-creating positive futures for nature and people. It seeks to open up a diversity of futures through mainly three value perspectives on nature – Nature for Nature, Nature for Society, and Nature as Culture. This paper describes how the NFF can be applied in modelling to support decision-making. First, we describe key considerations for the NFF in developing qualitative and quantitative scenarios: i) multiple value perspectives on nature as a state space where pathways improving nature toward a frontier can be represented, ii) mutually reinforcing key feedbacks of social-ecological systems that are important for nature conservation and human wellbeing, iii) indicators of multiple knowledge systems describing the evolution of complex social-ecological dynamics. We then present three approaches to modelling Nature Futures scenarios in the review, screening, and design phases of policy processes. This paper seeks to facilitate the integration of relational values of nature in models and strengthen modelled linkages across biodiversity, nature’s contributions to people, and quality of life.

Global Environmental Change↗
USGS2015

Broadening the regulated-river management paradigm: A case study of the forgotten dead zone hindering Pallid Sturgeon recovery

The global proliferation of dams within the last half century has prompted ecologists to understand the effects of regulated rivers on large-river fishes. Currently, much of the effort to mitigate the influence of dams on large-river fishes has been focused on downriver effects, and little attention has been given to upriver effects. Through a combination of field observations and laboratory experiments, we tested the hypothesis that abiotic conditions upriver of the dam are the mechanism for the lack of recruitment in Pallid Sturgeon ( Scaphirhynchus albus ), an iconic large-river endangered species. Here we show for the first time that anoxic upriver habitat in reservoirs (i.e., the transition zone between the river and reservoir) is responsible for the lack of recruitment in Pallid Sturgeon. The anoxic condition in the transition zone is a function of reduced river velocities and the concentration of fine particulate organic material with high microbial respiration. As predicted, the river upstream of the transition zone was oxic at all sampling locations. Our results indicate that transition zones are an ecological sink for Pallid Sturgeon. We argue that ecologists, engineers, and policy makers need to broaden the regulated-river paradigm to consider upriver and downriver effects of dams equally to comprehensively mitigate altered ecosystems for the benefit of large-river fishes, especially for the Pallid Sturgeon.

Fisheries↗
USGS2024

Effects of episodic stream dewatering on brook trout spatial population structure

Stream dewatering is expected to become more prevalent due to climate change, and we explored the potential consequences for brook trout ( Salvelinus fontinalis) within a temperate forest ecosystem in eastern North America. We estimated fish density within stream pools ( n = 386) from electrofishing surveys over 10 years (2012–2021) to compare a stream that exhibits episodic dewatering (Paine Run) against a stream of similar size that remains flow-connected (Staunton River) within Shenandoah National Park, Virginia (U.S.A.). Annual surveys encompassed fluvial distances ranging from 2.6 to 4.4 km in each stream. Mean annual fish density (fish/pool m 2 ) was not different between streams for juvenile or adult age classes, but spatial variation in density was greater in Paine Run for both age classes of fish. Paine Run also included a greater proportion of unoccupied pools than Staunton River and exhibited stronger spatial autocorrelation in fish density among nearby pools, suggesting dispersal limitation due to surface flow fragmentation. Fish density in pools increased during years with low summer precipitation, and this effect was observed in both streams but was stronger in Paine Run than Staunton River, further indicating the importance of fish movement into pools in response to low-flow thresholds. Our results indicate the importance of pools as ecological refuges during low-flow conditions and that episodic dewatering may affect extirpation risks for brook trout by sequestering more fish into fewer areas. Our findings also highlight the importance of hydrological variation within stream networks because downstream river gages could not predict the observed spatial heterogeneity in fish density or pool occupancy.

Freshwater Biology↗