Topographic, soil, and climate drivers of drought sensitivity in forests and shrublands of the Pacific Northwest, USA

Scientific Reports, Journal Year: 2020, Volume and Issue: 10(1)

Published: Oct. 28, 2020

Abstract Climate change is anticipated to increase the frequency and intensity of droughts, with major impacts ecosystems globally. Broad-scale assessments vegetation responses drought are needed anticipate, manage, potentially mitigate climate-change effects on ecosystems. We quantified sensitivity in Pacific Northwest, USA, as percent reduction greenness under droughts relative baseline moisture conditions. At a regional scale, shrub-steppe ecosystems—with drier climates lower biomass—showed greater than conifer forests. However, variability was considerable within biomes mediated by landscape topography, climate, soil characteristics. Drought generally areas higher elevation, bulk density. Ecosystems high included dry forests along ecotones shrublands, Rocky Mountain subalpine forests, cold upland sagebrush communities. In valley bottoms low density available water capacity showed reduced sensitivity, suggesting their potential refugia. These regional-scale drought-sensitivity patterns discerned from remote sensing can complement plot-scale studies plant physiological help inform climate-adaptation planning conditions intensify.

Language: Английский

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Vulnerable Waters are Essential to Watershed Resilience

Ecosystems, Journal Year: 2022, Volume and Issue: 26(1), P. 1 - 28

Published: Feb. 7, 2022

Watershed resilience is the ability of a watershed to maintain its characteristic system state while concurrently resisting, adapting to, and reorganizing after hydrological (for example, drought, flooding) or biogeochemical excessive nutrient) disturbances. Vulnerable waters include non-floodplain wetlands headwater streams, abundant components representing most distal extent freshwater aquatic network. are hydrologically dynamic biogeochemically reactive systems, storing, processing, releasing water entrained (that is, dissolved particulate) materials along expanding contracting networks. The functions emerging from these processes affect magnitude, frequency, timing, duration, storage, rate change material energy fluxes among downstream waters, thereby maintaining states imparting resilience. We present here conceptual framework for understanding how vulnerable confer demonstrate individual cumulative vulnerable-water modifications reduced extent, altered connectivity) watershed-scale disturbance response recovery, which decreases can trigger transitions across thresholds alternative conducive increased flood frequency nutrient concentrations). subsequently describe resilient watersheds require spatial heterogeneity temporal variability in interactions between terrestrial systems down-gradient necessitates attention conservation restoration their connectivity gradients. To conclude, we provide actionable principles articulate research needs further science management.

Language: Английский

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Ephemeral stream water contributions to United States drainage networks

Science, Journal Year: 2024, Volume and Issue: 384(6703), P. 1476 - 1482

Published: June 27, 2024

Ephemeral streams flow only in direct response to precipitation and are ubiquitous landscape features. However, little is known about their influence on downstream rivers. Here, we modeled ephemeral stream water contributions the contiguous United States network of more than 20 million rivers, lakes, reservoirs, finding that contribute, average, 55% discharge exported from regional river systems, as defined by Geological Survey. Our results show connectivity a substantial pathway through which associated nutrients pollution may enter perennial drainage quality. We provide quantitative insight into implications differing interpretations regulatory jurisdiction under Clean Water Act, including current standard adopted Supreme Court 2023.

Language: Английский

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Stream Network Dynamics of Non‐Perennial Rivers: Insights From Integrated Surface‐Subsurface Hydrological Modeling of Two Virtual Catchments

Water Resources Research, Journal Year: 2024, Volume and Issue: 60(2)

Published: Feb. 1, 2024

Abstract Understanding the spatio‐temporal dynamics of runoff generation in headwater catchments is challenging, due to intermittent and fragmented nature surface flows. The active stream network non‐perennial rivers contracts expands, with a dynamic behavior that depends on complex interplay among climate, topography, geology. In this work, CATchment HYdrology, an integrated surface–subsurface hydrological model (ISSHM), used simulate two virtual same, spatially homogeneous, subsurface characteristics (hydraulic conductivity, porosity, water retention curves) but different morphology. We run sets simulations reproduce sequence steady‐states at catchment wetness levels transient conditions analyze joint variations length ( L ) discharge outlet Q high resolutions. shape curves differs does not depend climate forcing, as it mainly controlled by underlying topography. then analyzed suitability topographic index contributing area identify spatial configuration maximum catchments. These morphometric parameters provided good estimate distribution flowing both study Our numerical indicate ISSHMs have potential accurately describe networks processes driving such that, overall, they can be useful tools gain insights into main physical drivers streams.

Language: Английский

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Dynamic stream network intermittence explains emergent dissolved organic carbon chemostasis in headwaters

Hydrological Processes, Journal Year: 2019, Volume and Issue: 33(13), P. 1926 - 1936

Published: April 6, 2019

Abstract Dissolved organic carbon (DOC) concentrations vary among headwaters, with variation typically decreasing watershed area. We hypothesized that streamflow intermittence could be an important source of in DOC across a small watershed, through (a) temporal legacies drying on matter accumulation and biotic communities (b) spatial patterns connectivity sources. To test these hypotheses, we conducted three synoptic water chemistry sampling campaigns 25.5‐km 2 south‐eastern Idaho during early spring, late summer, fall. Using changepoint analysis, found variability collapsed at consistent location (watershed areas ~1.3 to ~1.8 km ) seasons, which coincided the area where (~1.5 ). mechanisms may affect DOC, developed temporal, spatial, spatio‐temporal metrics related concentrations. Streamflow was strong predictor but different predicted depending season. Seasonal changes effects reflected seasonal from instream flowpath controls. A metric captured sources significantly high flows, when is controlled by transport. In contrast, reach‐scale growing season, processes legacy (e.g., diminished biological communities) would likely DOC. The extend beyond point. Our results suggest do not propagate downstream this system. Instead, snapshots upstream reach are critical for understanding sources, drive even perennial reaches.

Language: Английский

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Influence of groundwater and topography on stream drying in semi‐arid headwater streams

Hydrological Processes, Journal Year: 2021, Volume and Issue: 35(5)

Published: April 22, 2021

Abstract Non‐perennial streams comprise over half of the global stream network and impact downstream water quality. Although aridity is a primary driver drying globally, surface flow permanence varies spatially temporally within many headwater streams, suggesting that these complex patterns may be driven by topographic subsurface factors. Indeed, factors affect shallow groundwater flows in perennial systems, but there has been only limited characterisation residence times contributions to intermittent streams. Here, we asked how times, streamflow, topography interact control We evaluated this overarching question eight semi‐arid catchments based on observations during low‐flow period, coupled with tracer‐based times. For one catchment, analysed seasonal recession rewetting period using sensor was interspersed between monitoring locations, linked inputs topography. found poor relationship flowing extent ( R 2 < 0.24). indicated old present all also occurred each them, old, deep flowpaths are insufficient sustain flows. timing at any given point typically coincided decrease contribution from near‐surface sources an increased relative streamflow location, whereas spatial pattern correlated locations where were most seasonally variable. Topographic metrics explained ~30% variability permanence, surprisingly, no correlation down‐valley storage area. Because patterns, future studies should pair dense properties, such as hydraulic conductivity transmissivity, permanence.

Language: Английский

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Drought in intermittent river and ephemeral stream networks

Ecohydrology, Journal Year: 2021, Volume and Issue: 15(5)

Published: Nov. 27, 2021

Abstract Intermittent rivers and ephemeral streams (IRES), those watercourses that periodically cease to flow or dry, are the world's most widespread type of river ecosystem. Our understanding natural hydrology ecology IRES has greatly improved, but their responses extreme events such as drought remain a research frontier. In this review, we present state art, knowledge gaps directions on droughts in from an ecohydrological perspective. We clarify definition IRES, giving recommendations promote transferability how studies characterize non‐perennial stream networks. Based systematic search literature, also identify common patterns sources variation ecological provide roadmap for further enable improved management during hydrological events. Confusion terminology lack tools assess may have hindered development IRES. found 44% confused term with seasonal drying measure transferable way minority. Studies networks still rare limited few climatic zones organisms mainly explored perennial sections. review highlights need additional topic inform conservation.

Language: Английский

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Spatial and temporal patterns of flow intermittency in a Mediterranean basin using the SWAT+ model

Hydrological Sciences Journal, Journal Year: 2022, Volume and Issue: 68(2), P. 276 - 289

Published: Dec. 6, 2022

Non-perennial rivers and streams are ubiquitous. Nonetheless, our understanding of their hydrological patterns is minimal. Hydrological models powerful tools to study characterize patterns, but few can simulate extremes such as non-flow events. We aimed capture accurately the flow intermittency spatial temporal in a Mediterranean river basin with restructured Soil Water Assessment Tool (SWAT+). calibrated model using multi-objective optimization algorithm data from two gauging stations mainstream for period 2000–2020. Furthermore, we validated simulations against stage series at 14 stations. The results indicated that simulates low flows period. observed significant variation both space time remarkable inter-annual variability. also an increase over

Language: Английский

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Unveiling the hidden dynamics of intermittent surface water: A remote sensing framework

Remote Sensing of Environment, Journal Year: 2024, Volume and Issue: 311, P. 114285 - 114285

Published: June 27, 2024

Language: Английский

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Variability of stream extents controlled by flow regime and network hydraulic scaling

Hydrological Processes, Journal Year: 2021, Volume and Issue: 35(3)

Published: Feb. 7, 2021

Abstract Stream networks expand and contract through time, impacting chemical export, aquatic habitat, water quality. Although recent advances improve prediction of the extent wetted channel network ( L ) based on discharge at catchment outlet Q ), controls temporal variability remain poorly understood unquantified. Here we develop a quantitative, conceptual framework to explore how flow regime stream hydraulic scaling factors co‐determine relative in (denoted here as total drainage density). Network determines much changes for change , while describes time. We compiled datasets co‐located dynamic mapping analyze all globally available empirical data using presented framework. found that although is universally damped (i.e., streamflow relatively more variable time than extent), relationship elastic, meaning given increase headwater catchments will experience greater‐than‐proportional increases . Thus, under anticipated climatic shifts towards volatile precipitation, extents can be expected even itself. Comparison between inferred from ‐ blue lines USGS topographic maps shows widespread underestimation by line network.

Language: Английский

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