Emerging dominance of summer rainfall driving High Arctic terrestrial-aquatic connectivity

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: March 4, 2021

Abstract Hydrological transformations induced by climate warming are causing Arctic annual fluvial energy to shift from skewed (snowmelt-dominated) multimodal (snowmelt- and rainfall-dominated) distributions. We integrated decade-long hydrometeorological biogeochemical data the High show that shifts in timing magnitude of discharge patterns stream power budgets material transfer regimes undergo fundamental changes. Increased late summer rainfall enhanced terrestrial-aquatic connectivity for dissolved particulate fluxes. Permafrost disturbances (<3% watersheds’ areal extent) reduced watershed-scale organic carbon export, offsetting concurrent increased export undisturbed watersheds. To overcome buffering capacity transferring (30 ± 9 Watt), events had increase an order magnitude, indicating landscape is primed accelerated geomorphological change when future magnitudes consequent pluvial responses exceed current continuum.

Language: Английский

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Dwarf Shrubs Impact Tundra Soils: Drier, Colder, and Less Organic Carbon

Ecosystems, Journal Year: 2021, Volume and Issue: 24(6), P. 1378 - 1392

Published: Feb. 2, 2021

Abstract In the tundra, woody plants are dispersing towards higher latitudes and altitudes due to increasingly favourable climatic conditions. The coverage height of increasing, which may influence soils tundra ecosystem. Here, we use structural equation modelling analyse 171 study plots examine if affect growing-season topsoil moisture temperature (< 10 cm) as well soil organic carbon stocks 80 cm). our setting, consider hierarchy ecosystem by controlling for other factors, such topography, wintertime snow depth overall plant that potentially properties in this dwarf shrub-dominated landscape northern Fennoscandia. We found strong links from topography both vegetation soil. Further, multiple properties: dominance inversely correlated with moisture, temperature, (standardised regression coefficients = − 0.39; 0.22; 0.34, respectively), even when features. Our results indicate shrubs lead drier, colder, contain less carbon. Thus, there mechanisms through soils.

Language: Английский

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Arctic shrub expansion revealed by Landsat-derived multitemporal vegetation cover fractions in the Western Canadian Arctic

Remote Sensing of Environment, Journal Year: 2022, Volume and Issue: 281, P. 113228 - 113228

Published: Sept. 9, 2022

Warming induced shifts in tundra vegetation composition and structure, including circumpolar expansion of shrubs, modifies ecosystem structure functioning with potentially global consequences due to feedback mechanisms between climate. Satellite-derived indices indicate widespread greening the surface, often associated regional evidence shrub obtained from long-term ecological monitoring repeated orthophotos. However, explicitly quantifying across large scales using satellite observations requires characterising fine-scale mosaic Arctic types beyond index-based approaches. Although previous studies have illustrated potential estimating fractional cover various Plant Functional Types (PFTs) imagery, limited availability reference data space time has constrained deriving fraction series capable detecting expansion. We applied regression-based unmixing synthetic training build multitemporal machine learning models order estimate shrubs other surface components Mackenzie Delta Region for six intervals 1984 2020. trained Kernel Ridge Regression (KRR) Random Forest (RFR) Landsat-derived spectral-temporal-metrics generated pure class spectra directly imagery. Independent validation very-high-resolution imagery suggested that KRR outperforms RFR, a MAE 10.6% remaining MAEs 3.0 11.2%. Canopy-forming were well modelled all densities, coniferous tree tended be overestimated differentiating herbaceous lichen was challenging. Shrub expanded by on average + 2.2% per decade entire study area 4.2% within low tundra, while relative changes strongest northernmost regions. In conjunction expansion, we observed plant decline. Our results corroborate perception replacement homogenisation communities facilitated competitive advantage species under warming The proposed method allows multidecadal quantitative estimates at 30 m resolution, initiating new opportunities mapping past present PFTs can help advance our understanding vast heterogeneous biome.

Language: Английский

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A review of open top chamber (OTC) performance across the ITEX Network

Arctic Science, Journal Year: 2022, Volume and Issue: 9(2), P. 331 - 344

Published: Oct. 19, 2022

Open top chambers (OTCs) were adopted as the recommended warming mechanism by International Tundra Experiment network in early 1990s. Since then, OTCs have been deployed across globe. Hundreds of papers reported impacts on abiotic environment and biota. Here, we review OTC physical environment, with comments appropriateness using to characterize response biota warming. The purpose this is guide readers previously published work provide recommendations for continued use understand implications low stature ecosystems. In short, a useful tool experimentally manipulate temperature; however, characteristics magnitude varies greatly different environments; therefore, it important document chamber performance maximize interpretation biotic response. When coupled long-term monitoring, experiments are valuable means climate change natural

Language: Английский

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Strong isoprene emission response to temperature in tundra vegetation

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(38)

Published: Sept. 12, 2022

Emissions of biogenic volatile organic compounds (BVOCs) are a crucial component biosphere–atmosphere interactions. In northern latitudes, climate change is amplified by feedback processes in which BVOCs have recognized, yet poorly quantified role, mainly due to lack measurements and concomitant modeling gaps. Hence, current Earth system models mostly rely on temperature responses measured vegetation from lower rendering their predictions highly uncertain. Here, we show how tundra isoprene emissions respond vigorously increases, compared model results. Our unique dataset direct eddy covariance ecosystem-level two contrasting ecosystems exhibited Q 10 (the factor the emission rate increases with °C rise temperature) coefficients up 20.8, that is, 3.5 times 5.9 derived equivalent calculations. Crude estimates using observed indicate could enhance 41% (87%)—that 46% (55%) more than estimated models—with 2 (4 °C) warming. results demonstrate possesses potential substantially boost its response future rising temperatures, at rates exceed predictions.

Language: Английский

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Experimental warming altered plant functional traits and their coordination in a permafrost ecosystem

New Phytologist, Journal Year: 2023, Volume and Issue: 240(5), P. 1802 - 1816

Published: July 11, 2023

Knowledge about changes in plant functional traits is valuable for the mechanistic understanding of warming effects on ecosystem functions. However, observations have tended to focus aboveground traits, and there little information belowground or coordination above- under climate warming, particularly permafrost ecosystems. Based a 7-yr field experiment, we measured 26 four dominant species, explored community composition trait networks response experimental Tibetan Plateau. Experimental shifted community-level toward more acquisitive values, with earlier green-up, greater height, larger leaves, higher photosynthetic resource-use efficiency, thinner roots, specific root length nutrient concentrations. had negligible effect terms diversity. In addition, hub which highest centrality network from area leaf area. These results demonstrate that exhibit consistent adaptive strategies, warmer environments. Such could provide an advantage plants environmental change.

Language: Английский

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The value of hyperspectral UAV imagery in characterizing tundra vegetation

Remote Sensing of Environment, Journal Year: 2024, Volume and Issue: 308, P. 114175 - 114175

Published: May 15, 2024

The fine-scale spatial heterogeneity of low-growth Arctic tundra landscapes necessitates the use high-spatial-resolution remote sensing data for accurate detection vegetation patterns. While multispectral satellite and aerial imaging, including uncrewed vehicles (UAVs), are common approaches, hyperspectral UAV imaging has not been thoroughly explored in these ecosystems. Here, we assess added value relative to modelling plant communities oroarctic heaths Saariselkä, northern Finland. We compare three different spectral compositions: 4-channel broadband images, 5-channel images 112-channel narrowband images. Based on field plot data, estimate vascular aboveground biomass, leaf area index, species richness, Shannon's diversity community composition. topographic information compile 12 explanatory datasets random forest regression classification. For biomass highest R2 values were 0.60 0.65, respectively, variables most important. In best models biodiversity metrics richness index 0.53 0.46, with hyperspectral, topographic, having high importance. 4 floristically determined clusters, both classifications fuzzy cluster membership regressions conducted. Overall accuracy (OA) classification was 0.67 at best, while estimated an 0.29–0.53. Variable importance heavily dependent composition, but multispectral, all selected composition models. Hyperspectral generally outperformed ones when excluded. With this difference diminished, performance improvements from limited 0–10 percentage point increases R2, largest occurring lowest R2. These results suggest that can outperform mostly sufficient practical applications heaths.

Language: Английский

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Muskox status, recent variation, and uncertain future

AMBIO, Journal Year: 2019, Volume and Issue: 49(3), P. 805 - 819

Published: June 11, 2019

Muskoxen (Ovibos moschatus) are an integral component of Arctic biodiversity. Given low genetic diversity, their ability to respond future and rapid change is unknown, although paleontological history demonstrates adaptability within limits. We discuss status limitations current monitoring, summarize circumpolar recent variations, delineating all 55 endemic or translocated populations. Acknowledging uncertainties, global abundance ca 170 000 muskoxen. Not populations thriving. Six in decline, as recently the turn century, one these was largest population world, equaling 41% today's total abundance. Climate, diseases, anthropogenic changes likely principal drivers muskox result multiple stressors that vary temporally spatially. Impacts muskoxen precipitated by habitat loss/degradation, altered vegetation species associations, pollution, harvest. Which elements relevant for a specific will vary, cumulative interactions. Our summaries highlight importance harmonizing existing data, intensifying long-term monitoring efforts including demographics health assessments, standardizing implementing protocols, increasing stakeholder engagement/contributions.

Language: Английский

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Biotic rescaling reveals importance of species interactions for variation in biodiversity responses to climate change

Proceedings of the National Academy of Sciences, Journal Year: 2020, Volume and Issue: 117(37), P. 22858 - 22865

Published: Aug. 31, 2020

Generality in understanding biodiversity responses to climate change has been hampered by substantial variation the rates and even directions of response a given climate. We propose that such context dependencies can be clarified rescaling gradients terms underlying biological processes, with biotic interactions as particularly important process. tested this approach replicated field experiment where entire montane grassland communities were transplanted direction expected temperature and/or precipitation change. In line earlier work, we found considerable across sites community dynamics However, these complex could substantially reduced or eliminated drivers proxies plant-plant interactions. Specifically, bryophytes limited colonization new species into local communities, whereas cover those colonists, along bryophytes, primary extinctions. These specific are relatively understudied, suggesting for future work similar systems. More generally, success our explaining simplifying landscape-level suggests developing testing relevant processes fruitful building more general models

Language: Английский

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Microbial activity in alpine soils under climate change

The Science of The Total Environment, Journal Year: 2021, Volume and Issue: 783, P. 147012 - 147012

Published: April 11, 2021

Language: Английский

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