Arctic tundra shrubification: a review of mechanisms and impacts on ecosystem carbon balance

Environmental Research Letters, Journal Year: 2021, Volume and Issue: 16(5), P. 053001 - 053001

Published: April 23, 2021

Abstract Vegetation composition shifts, and in particular, shrub expansion across the Arctic tundra are some of most important widely observed responses high-latitude ecosystems to rapid climate warming. These changes vegetation potentially alter ecosystem carbon balances by affecting a complex set soil–plant–atmosphere interactions. In this review, we synthesize literature on (a) expansion, (b) key climatic environmental controls mechanisms that affect (c) impacts balance, (d) research gaps future directions improve process representations land models. A broad range evidence, including in-situ observations, warming experiments, remotely sensed indices have shown increases growth abundance woody plants, particularly tall deciduous shrubs, advancing shrublines circumpolar Arctic. This recent is affected several interacting factors warming, accelerated nutrient cycling, changing disturbance regimes, local variation topography hydrology. Under warmer conditions, shrubs can be more competitive than other plant functional types because their taller maximum canopy heights often dense structure. Competitive abilities vs herbaceous plants also controlled traits investments retention strategies leaves, stems, roots. Overall, may enhancing uptake altering respiration, through feedback snowpack dynamics, permafrost degradation, surface energy litter inputs. Observed projected subsequent effects feedbacks system. Land models, those integrated Earth System Models, need account for differences control interactions accurately predict decadal- centennial-scale dynamics.

Language: Английский

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Evasion of tipping in complex systems through spatial pattern formation

Science, Journal Year: 2021, Volume and Issue: 374(6564)

Published: Oct. 8, 2021

Resilience to tipping points in ecosystems Spatial pattern formation has been proposed as an early warning signal for dangerous and imminent critical transitions complex systems, including ecosystems. Rietkerk et al . review how Earth system components can actually evade catastrophic through various pathways of spatial formation. With mathematical real-world examples, they argue that evading enhancing resilience could be relevant many until now were known prone. Many these systems may more resilient than currently thought because overlooked dynamics multiple stable states, thus not undergo or with global change. —AMS

Language: Английский

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Distance sampling surveys reveal 17 million vertebrates directly killed by the 2020’s wildfires in the Pantanal, Brazil

Scientific Reports, Journal Year: 2021, Volume and Issue: 11(1)

Published: Dec. 16, 2021

Abstract Anthropogenic factors have significantly influenced the frequency, duration, and intensity of meteorological drought in many regions globe, increased frequency wildfires is among most visible consequences human-induced climate change. Despite fire role determining biodiversity outcomes different ecosystems, can cause negative impacts on wildlife. We conducted ground surveys along line transects to estimate first-order impact 2020 vertebrates Pantanal wetland, Brazil. adopted distance sampling technique densities number dead 39,030 square kilometers affected by fire. Our estimates indicate that at least 16.952 million were killed immediately fires Pantanal, demonstrating such an event wet savanna ecosystems. The case also reminds us cumulative widespread burning would be catastrophic, as recurrence may lead impoverishment ecosystems disruption their functioning. To overcome this unsustainable scenario, it necessary establish proper biomass fuel management avoid caused over ecosystem services.

Language: Английский

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Polar Regions

Cambridge University Press eBooks, Journal Year: 2023, Volume and Issue: unknown, P. 2319 - 2368

Published: June 22, 2023

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Language: Английский

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Looking back on biodiversity change: lessons for the road ahead

Philosophical Transactions of the Royal Society B Biological Sciences, Journal Year: 2023, Volume and Issue: 378(1881)

Published: May 29, 2023

Estimating biodiversity change across the planet in context of widespread human modification is a critical challenge. Here, we review how has changed recent decades scales and taxonomic groups, focusing on four diversity metrics: species richness, temporal turnover, spatial beta-diversity abundance. At local scales, all metrics includes many examples both increases declines tends to be centred around zero, but with higher prevalence declining trends (increasing similarity composition space or biotic homogenization) The exception this pattern changes through time observed most assemblages. Less known about at regional although several studies suggest that richness are more prevalent than declines. Change global scale hardest estimate accurately, extinction rates probably outpacing speciation rates, elevated. Recognizing variability essential accurately portray unfolding, highlights much remains unknown magnitude direction multiple different scales. Reducing these blind spots allow appropriate management actions deployed. This article part theme issue ‘Detecting attributing causes change: needs, gaps solutions’.

Language: Английский

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Foundations and Future Directions for Causal Inference in Ecological Research

Ecology Letters, Journal Year: 2025, Volume and Issue: 28(1)

Published: Jan. 1, 2025

ABSTRACT Ecology often seeks to answer causal questions, and while ecologists have a rich history of experimental approaches, novel observational data streams the need apply insights across naturally occurring conditions pose opportunities challenges. Other fields developed inference approaches that can enhance expand our ability ecological questions using or data. However, lack comprehensive resources applying settings jargon from multiple disciplines creates barriers. We introduce for inference, discussing main frameworks counterfactual how differs other research aims key challenges; application in quasi‐experimental study designs; appropriate interpretation results given their assumptions biases; foundational papers; requirements trade‐offs between internal external validity posed by different designs. highlight these designs generally prioritise over generalisability. Finally, we identify considerations further integrate with synthesis science meta‐analysis spatiotemporal scales at which is possible. advocate ecology as field collectively define best practices inference.

Language: Английский

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Is subarctic forest advance able to keep pace with climate change?

Global Change Biology, Journal Year: 2020, Volume and Issue: 26(7), P. 3965 - 3977

Published: April 13, 2020

Recent climate warming and scenarios for further have led to expectations of rapid movement ecological boundaries. Here we focus on the circumarctic forest-tundra ecotone (FTE), which represents an important bioclimatic zone with feedbacks from forest advance corresponding tundra disappearance (up 50% loss predicted this century) driving widespread climatic changes. We address FTE history relations over 20th century, using response data 151 sites across area site-specific data. Specifically, investigate spatial uniformity advance, statistical associations century trends, whether rates match change velocities (CCVs). Study diverged into four regions (Eastern Canada; Central Western Canada Alaska; Siberia; Eurasia) based their history, although all were characterized by similar qualitative patterns behaviour (with about half showing advancing behaviour). The main between trend variables indicate importance precipitation rather than temperature both quantitative behaviours, non-growing season as well growing months. Poleward latitudinal differed significantly among regions, being smallest in Eastern (~10 m/year) largest Eurasia (~100 m/year). These 1-2 orders magnitude smaller expected if vegetation distribution remained equilibrium climate. many biotic abiotic factors influencing make poleward matching 21st CCVs (~103 -104 unlikely. lack empirical evidence swift relocation discrepancy CCV contradict model-based assumptions warrant caution when assessing global-change-related implications, including land-atmosphere carbon sequestration.

Language: Английский

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Woody plant encroachment enhanced global vegetation greening and ecosystem water‐use efficiency

Global Ecology and Biogeography, Journal Year: 2021, Volume and Issue: 30(12), P. 2337 - 2353

Published: Aug. 31, 2021

Abstract Aim Encroachment of woody plants into grasslands and savannas (WPE) has been observed world‐wide. However, the general ecohydrological effects this striking change in land cover are uncertain owing to divergent results various areas unknown global spatial distribution. Here, we reveal patterns dynamics WPE its on leaf area index (LAI), gross primary production (GPP), components evapotranspiration (ET) ecosystem water‐use efficiency (EWUE). Location Global. Time period Contemporary. Major taxa studied Woody plants. Methods We used remote sensing identify distribution 2002–2018, validated at 442 sites, analysed pattern across geographical gradients. The multi‐time‐scale impacts were revealed through pairwise comparison. Differences among biomes/climate zones compared by Kruskal–Wallis test. relationship vegetation greening EWUE explored. Results Global expanded persistently from 2002 2018, but rate increase decreased after 2010; spatially, average was .3%/year. High values 2018 occurred arid semi‐arid regions, with peak multi‐annual mean precipitation 350–400 mm. Pairwise comparison showed that increased LAI, GPP, ET ratio transpiration ET, strongest summer, enhanced annual EWUE. Both pixel‐ site‐level mainly greening. above findings varied bioclimatic conditions; particularly areas, positively correlated remarkably improved Main conclusions ongoing contributed elevated productivity increasing LAI partitioning more water transpiration; these indicate process should be incorporated carbon cycle ecohydrology models. attention also focused controlling adverse consequences areas.

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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The success of woody plant removal depends on encroachment stage and plant traits

Nature Plants, Journal Year: 2022, Volume and Issue: 9(1), P. 58 - 67

Published: Dec. 21, 2022

Language: Английский

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