Biological Diversity in Headwater Streams

Water, Journal Year: 2019, Volume and Issue: 11(2), P. 366 - 366

Published: Feb. 21, 2019

Headwaters, the sources of all stream networks, provide habitats that are unique from other freshwater environments and used by a specialised subset aquatic species. The features headwaters special include predator-free or competitor-free spaces; specific resources (particularly detrital based); moderate variations in flows, temperature discharge. Headwaters key for some life stages large number species across just about phyla divisions. Some headwaters, including isolation small population sizes, have allowed evolutionary radiation many groups organisms within beyond those habitats. As easily engineered physical spaces, degraded streambank development, ditching even burial. Headwater streams among most sensitive ecosystems due to their intimate linkage with catchments how they impacted. ecosystem specialist species, headwater deserve better stewardship.

Language: Английский

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Extreme learning machine-based prediction of daily water temperature for rivers

Environmental Earth Sciences, Journal Year: 2019, Volume and Issue: 78(6)

Published: March 1, 2019

Language: Английский

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Assemblage-based biomonitoring of freshwater ecosystem health via multimetric indices: A critical review and suggestions for improving their applicability

Water Biology and Security, Journal Year: 2022, Volume and Issue: 1(3), P. 100054 - 100054

Published: May 29, 2022

Freshwater biota are more comprehensive and direct indicators of biological impacts, meaningful to the public than water quality or physical habitat surrogates. biotic data multiple developed from them offer a much richer array for assessing impacts pollution controls limited set chemical measures. In recent decades, assemblage-based assessments by ecologists, environmental scientists, agencies have been employed globally determining condition of, threats to, freshwater ecosystems. A key step in this advance has development multimetric indices (MMIs) integrity (IBIs) based on quantitative algae, macrophyte, macroinvertebrate, fish riparian bird assemblages. Europe, where assemblages mandated ecosystem health, many multimetric. However, proliferation MMIs not always occurred through application rigorous study designs monitoring protocols, nor they effectively incorporated functional metrics, stressor assessments, statistical analyses. Therefore, review, we discuss eleven major concerns with (including logistical limitations) encourage widely applicable (transferable) MMI use implementation. Specifically, our focus reference conditions; sampling effort, methods, season; trophic guild definition; metric comprehensiveness, options, screening scoring; validation. could also benefit increased attention ecological mechanisms development, further improve understanding anthropogenic as well rehabilitation effects ecosystems globally. Paying closer designs, should better facilitate degraded ecosystems, aiding conservation healthy

Language: Английский

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Empirical Stream Thermal Sensitivities May Underestimate Stream Temperature Response to Climate Warming

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(7), P. 5453 - 5467

Published: June 7, 2019

Abstract Stream temperature has been increasing in tandem with air temperature, potentially negative impacts on cold‐water fish such as salmon. Assessing future stream change is critical for developing effective management responses. Empirical models of thermal sensitivity generally predict less warming compared to physically based models. Here we reconcile these discrepancies by using a process‐based hydrology and model simulate daily flow water forested headwater catchments maritime region under both historic projected climatic conditions. The primary reason that the empirical approach underestimates response climate it does not account memory catchment, especially related effect snow cover. sensitivities thus may underestimate warming. In addition, groundwater‐fed streams only resist short‐medium term, due lagged groundwater temperature. More understanding modeling regimes needed effectively manage aquatic ecosystems.

Language: Английский

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Temperature buffering by groundwater in ecologically valuable lowland streams under current and future climate conditions

Journal of Hydrology X, Journal Year: 2019, Volume and Issue: 3, P. 100031 - 100031

Published: March 14, 2019

Groundwater seepage influences the temperature of streams and rivers by providing a relatively cool input in summer warm winter. Because this, groundwater can be determining factor provision suitable water temperatures for aquatic biota. Climate warming affects stream temperatures, changes thermal characteristics leading to potential disappearance habitats. In this study importance two Dutch lowland its possible role mitigating effects climate change was determined combining field measurements modelling experiment. Stream using fibre optic cables (FO-DTS) sampling 222Rn were done map localized inflow. Several springs 'hot-spots' located which buffered A model constructed calibrated FO-DTS-measurements quantify energy fluxes acting on water. This way, contribution budget direct solar radiation, air separated. The then used simulate shading, climate. Shading shown an important control maxima. seemed buffer effect warming, potentially making dominated more robust. Protecting resources changing is survival species groundwater-fed systems, as both sustains flow buffers extremes.

Language: Английский

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Managing Freshwater Fish in a Changing Climate: Resist, Accept, or Direct

Fisheries, Journal Year: 2022, Volume and Issue: 47(6), P. 245 - 255

Published: Jan. 10, 2022

Abstract Climate change is altering the distribution, phenology (e.g., timing of spawning), and community dynamics freshwater fishes. Managers have three options for responding to these changes: “Resist” maintain or restore historic abiotic biological conditions; “Accept” manage within new “Direct” produce conditions considered desirable by humans. I discuss how inland fisheries management approaches stocking, regulations, habitat improvement, manipulations can be applied Resist-Accept-Direct (RAD) framework. also ways choose among ecological tipping points used determine when Resist no longer a feasible option managers must shift Accept Direct options.

Language: Английский

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Cold-water habitats, climate refugia, and their utility for conserving salmonid fishes

Canadian Journal of Fisheries and Aquatic Sciences, Journal Year: 2023, Volume and Issue: 80(7), P. 1187 - 1206

Published: March 15, 2023

Anthropogenic climate change is warming global temperatures, with significant implications for salmonid fishes that depend on the availability of cold water during one or more life stages. Along southern range extents many species, and elsewhere warm temperatures are increasingly problematic, identification protection restoration habitats may serve as refugia where local populations can persist emerging an important conservation tactic. In this perspective piece, we address concept utility refugia—drawing a distinction commonly considered thermal refuges—describe technological advances enable accurate temperature mapping species distribution modeling in lotic environments, outline key uncertainties opportunities to chart constructive path forward topic will continue grow importance. Identifying not panacea conservation, but argue there tangible benefits doing so, least which options it affords thinking acting strategically within context changing century.

Language: Английский

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Stuck in the middle: thermal regimes of coastal lagoons and estuaries in a warming world

Environmental Research Letters, Journal Year: 2023, Volume and Issue: 18(6), P. 061003 - 061003

Published: May 16, 2023

Abstract N/A

Language: Английский

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Thermal exposure of adult Chinook salmon and steelhead: Diverse behavioral strategies in a large and warming river system

PLoS ONE, Journal Year: 2018, Volume and Issue: 13(9), P. e0204274 - e0204274

Published: Sept. 21, 2018

Rising river temperatures in western North America have increased the energetic costs of migration and risk premature mortality many Pacific salmon (Oncorhynchus spp.) populations. Predicting managing risks for these populations requires data on acute cumulative thermal exposure, spatio-temporal distribution adverse conditions, potentially mitigating effects cool-water refuges. In this study, we paired radiotelemetry with archival temperature loggers to construct continuous, spatially-explicit histories 212 adult Chinook (O. tshawytscha) 200 steelhead mykiss). The fish amassed ~500,000 records (30-min intervals) while migrating through 470 kilometers Columbia Snake rivers en route spawning sites Idaho, Oregon, Washington. Spring- most summer-run migrated before reached annual highs; their body closely matched ambient had maxima lower River. contrast, individual fall-run near tolerance limits (20–22 °C) High elicited extensive use refuges tributary confluences, where were ~2–10 °C cooler than adjacent corridor. Many used weeks or more whereas was typically hours days, reflecting differences spawn timing. Almost no refuge detected a ~260-km reach barrier may frequently develop future warmer years. Within population, exposure strongly positively correlated (0.88 ≤ r 0.98) duration inconsistently associated (-0.28 0.09) date. All four likely experienced historically high mean maximum recent Expected responses include population-specific shifts phenology, reliance patchily-distributed refuges, natural selection favoring temperature-tolerant phenotypes.

Language: Английский

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Small dams alter thermal regimes of downstream water

Hydrology and earth system sciences, Journal Year: 2019, Volume and Issue: 23(11), P. 4509 - 4525

Published: Nov. 5, 2019

Abstract. The purpose of this study was to quantify the downstream impacts different types small dams on summer water temperature in lowland streams. We examined (1) regimes upstream and with structural characteristics, (2) relationships between stream anomalies climatic variables, watershed area, dam height, impoundment length surface residence time, (3) most significant variables explaining thermal behaviors, (4) effect considering a biological threshold 22 ∘C, calculation both number days above average hourly duration threshold. Water loggers were installed 11 Bresse region (France) monitored at 30 min intervals during (June September) over 2009–2016 period, resulting 13 paired time series (two sites for two summers, allowing opportunity compare cold hot summers). At 23 % dams, we observed increased maximum daily temperatures more than 1 ∘C; remaining changes −1 ∘C. Across sites, mean increase minimum 85 higher 0.5 hierarchically clustered based three anomaly variables: upstream–downstream differences (ΔTmax), (ΔTmin), amplitude (ΔTamp). cluster analysis identified main effects regime: Tmin associated Tmax either unchanged or slightly reduced impoundments low volume (i.e., shorter 0.7 d area less 35 000 m2), same order magnitude larger longer greater m2). These increases reached 2.4 ∘C certain structures potential impair structure aquatic communities functioning ecosystem. Overall, show that can meaningfully alter flowing waters, these be explained sufficient accuracy (R2=0.7) using simple measurements physical attributes. This finding may have importance modelers managers who desire understand restore fragmented thermalscapes river networks.

Language: Английский

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