Critical transitions in the Amazon forest system

Nature, Journal Year: 2024, Volume and Issue: 626(7999), P. 555 - 564

Published: Feb. 14, 2024

Abstract The possibility that the Amazon forest system could soon reach a tipping point, inducing large-scale collapse, has raised global concern 1–3 . For 65 million years, Amazonian forests remained relatively resilient to climatic variability. Now, region is increasingly exposed unprecedented stress from warming temperatures, extreme droughts, deforestation and fires, even in central remote parts of 1 Long existing feedbacks between environmental conditions are being replaced by novel modify ecosystem resilience, increasing risk critical transition. Here we analyse evidence for five major drivers water on forests, as well potential thresholds those that, if crossed, trigger local, regional or biome-wide collapse. By combining spatial information various disturbances, estimate 2050, 10% 47% will be compounding disturbances may unexpected transitions potentially exacerbate climate change. Using examples disturbed across Amazon, identify three most plausible trajectories, involving different conditions. We discuss how inherent complexity adds uncertainty about future dynamics, but also reveals opportunities action. Keeping Anthropocene depend combination local efforts end degradation expand restoration, with stop greenhouse gas emissions.

Language: Английский

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Double stress of waterlogging and drought drives forest–savanna coexistence

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(33)

Published: Aug. 7, 2023

Forest-savanna boundaries are ecotones that support complex ecosystem functions and sensitive to biotic/abiotic perturbations. What drives their distribution today how it may shift in the future open questions. Feedbacks among climate, fire, herbivory, land use known drivers. Here, we show alternating seasonal drought waterlogging stress favors dominance of savanna-like ecosystems over forests. We track water-table depth as an indicator water when too deep oxygen shallow map forest/savanna occurrence within this double-stress space neotropics. find under a given annual precipitation, savannas favored landscape positions experiencing double stress, which is more common dry season strengthens (climate driver) but only found waterlogged lowlands (terrain driver). further hydrological changes at end century expose some flooded forests savanna expansion, affecting biodiversity soil carbon storage. Our results highlight importance hydrology understanding/predicting forest-savanna transitions changing world.

Language: Английский

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Distribution pattern of large old Ginkgo biloba in China under climate change scenarios

Ecology and Evolution, Journal Year: 2024, Volume and Issue: 14(5)

Published: May 1, 2024

Abstract Large old Ginkgo biloba trees (LOGTs), with profound ecological and cultural significance in China, face increasing threats from climate change human activities. We employed the BIOCLIM DOMAIN species distribution models to predict their spatial patterns under present doubled‐CO 2 scenario 2100. collected 604 validated LOGT occurrence records data on 19 bioclimate factors for analysis. Our study yielded a geographic pattern covering wide latitudinal belt extending south subtropical temperate zones central eastern concentrating low elevations coastal regions. The principal component analysis identified dominant bioclimatic shaping distribution, namely annual precipitation winter temperatures. generated predicted suitable habitats that match range well. However, future scenario, indicated habitat retentions mainly core areas losses southern edge of scattered pockets elsewhere. Some retained habitats, including excellent ones, will suffer fragmentation. new may permit some expansion migration but are beset by small patch size large interpatch distance, bringing fragmentation gene flow restrictions. anticipated projected decline highlights considerable poses long‐term survival precious natural‐cum‐cultural resource. Understanding underlying drivers distillation practical conservation measures can foster sustainable management vis‐a‐vis looming global change.

Language: Английский

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Biological Nano-Agrochemicals for Crop Production as an Emerging Way to Address Heat and Associated Stresses

Nanomaterials, Journal Year: 2024, Volume and Issue: 14(15), P. 1253 - 1253

Published: July 26, 2024

Climate change is a global problem facing all aspects of the agricultural sector. Heat stress due to increasing atmospheric temperature one most common climate impacts on agriculture. has direct effects crop production, along with indirect through associated problems such as drought, salinity, and pathogenic stresses. Approaches reported be effective mitigate heat include nano-management. Nano-agrochemicals nanofertilizers nanopesticides are emerging approaches that have shown promise against stress, particularly biogenic nano-sources. Nanomaterials favorable for production their low toxicity eco-friendly action. This review focuses different stresses production. Nano-management crops under including application nanopesticides, discussed. The potential limitations these nano-agrochemicals reviewed. Potential nanotoxicity need more investigation at local, national, levels, well additional studies into soil, plant, microbial properties processes.

Language: Английский

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Anthropogenic disturbance exacerbates resilience loss in the Amazon rainforests

Global Change Biology, Journal Year: 2023, Volume and Issue: 30(1)

Published: Nov. 1, 2023

Abstract Uncovering the mechanisms that lead to Amazon forest resilience variations is crucial predict impact of future climatic and anthropogenic disturbances. Here, we apply a previously used empirical metrics, lag‐1 month temporal autocorrelation (TAC), vegetation optical depth data in C‐band (a good proxy whole canopy water content) order explore how are impacted by human disturbances environmental drivers Brazilian Amazon. We found significantly increase risk critical transitions, median TAC value ~2.4 times higher human‐disturbed forests than intact forests, suggesting much lower disturbed forests. Additionally, less resilient land surface heat stress atmospheric Among with more closed thicker structure, which linked cover disturbance fraction, comparably resilient. These results further emphasize urgent need limit deforestation degradation through policy intervention maintain rainforests.

Language: Английский

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Groundwater dominates terrestrial hydrological processes in the Amazon at the basin and subbasin scales

Journal of Hydrology, Journal Year: 2023, Volume and Issue: 628, P. 130312 - 130312

Published: Oct. 18, 2023

Language: Английский

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Vegetation-rainfall coupling as an indicator of ecosystem state in a heterogeneous landscape

Ecological Indicators, Journal Year: 2023, Volume and Issue: 157, P. 111268 - 111268

Published: Nov. 20, 2023

Coexisting vegetation types in tropical landscapes can respond contrasting ways to rainfall, despite being the same climatic envelope. Understanding such heterogeneity vegetation-rainfall interactions is key for predicting how ecosystems might future environmental changes. Here we test whether temporal coupling between greenness and rainfall a good indicator of ecosystem state landscape. For this, study well-preserved landscape Brazilian Cerrado that formed by mosaics ecosystems, including savannas, dry forests gallery forests. First, correlate time-series quantify their each type. We then compare with other variables, as local-scale structural functional traits, well differences conditions which these exist. are set have distinct responsiveness rainfall. Commonly used tree cover height, do not depict marked types, particularly Dry strongest decrease during seasons, reflecting deciduousness on nutrient-richer soils. In contrast, increase season, when direct radiation peaks, likely due perennial access groundwater. Savannas less responsive more stable throughout year. Our findings suggest local abiotic contribute determining both distribution states savanna landscapes. Changes result climate land-use changes will alter future. metric may thus be useful assessing responses precipitation.

Language: Английский

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Soil not fire: Field, glasshouse and dendrochronology studies show how edaphic factors control post-fire woody plant growth across a sedgeland – forest boundary in Tasmania

Forest Ecology and Management, Journal Year: 2023, Volume and Issue: 553, P. 121639 - 121639

Published: Dec. 12, 2023

Western Tasmania contains large areas of treeless sedgeland interspersed with scrub and forest vegetation. Why these exist in a region wet enough to support rainforest remains unclear. Slower growth woody plants the than could be factor, because smaller are more likely killed by frequent fire before they mature set seed. However, there is little information regarding rates communities. We characterised soils compared small sedgeland, at two sites using diverse approaches: (i) field observational studies seedlings from broad range species that established following wildfire 2019 site 1; (ii) dendrochronological study myrtaceous shrubs had 1983 were 1 (iii) experiment which fertiliser was applied transplanted shrub Leptospermum scoparium 2. (iv) also used glasshouse test effects nutrients waterlogging on L. seedlings. Sedgeland organic poorly drained, whereas mineral well drained; surface but drained. Concentrations most soil nutrients, including total P, K, Ca, Mg Mn highest forest, although N sedgeland. At both sites, plant grew faster factor 1.7–3.4. When added seedlings, no difference between scrub. In experiment, limited low waterlogging. effect not apparent conditions dry. Our shows slow Tasmanian sedgelands associated infertile waterlogged soils. Fire disturbance sharpens boundary cause it.

Language: Английский

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Multi-factor weighted image fusion method for high spatiotemporal tracking of reservoir drawdown area and its vegetation dynamics

International Journal of Applied Earth Observation and Geoinformation, Journal Year: 2024, Volume and Issue: 129, P. 103855 - 103855

Published: April 25, 2024

Reservoir drawdown areas (RDAs) with distinct dry-wet cycles and vegetation dynamics have emerged as significant hotspots for carbon-related activities. However, high-resolution spatiotemporal tracking of the variations RDAs remains challenging because they often change dramatically are controlled by both human activities natural factors. Herein, a modified image fusion method was proposed to capture rapid in integrating impact factor information into analysis. The capability tested Danjiangkou (DJK) it is largest artificial freshwater lake Asia highly variable RDA, since surrounded gently sloping plains or hills. results showed that workflow produced reliable predictions (r=0.83,RMSE=0.097) compared original Enhanced Spatial Temporal Adaptive Reflectance Fusion Model (ESTARFM) (r=0.60,RMSE=0.195), demonstrating improved mapping water surface changes dynamics. Using method, 15-d RDA were derived from 2013 2022 30-m resolution. interannual maximum estimated be 278 km2 after dam elevated 2013. Normalized Difference Vegetation Index (NDVI) decreased inundation frequency (IF) increased. Mean NDVI growing season (May–October) 0.109 (17.6 %) 0.156 (26.0 under 30 %–40 % IF 60 %–70 IF, respectively, 0 %–10 which referred "natural" considering its rare inundation. Moreover, mean length only 63 19 d respectively. Furthermore, 77.3 exhibited decrease NDVI, whereas 22.7 an unusual increase, possibly due selection dominant species well-adapted during succession. Overall, this study not new high monitoring RDAs, but also highlighted importance within accurate estimation their carbon budgets.

Language: Английский

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Edaphic factors control fire-prone sedgeland and Eucalyptus forest mosaics in southwestern Tasmania

CATENA, Journal Year: 2024, Volume and Issue: 242, P. 108114 - 108114

Published: May 22, 2024

An unresolved, key question in plant ecology and biogeography is the relative importance of fire disturbance edaphic factors controlling treeless-forest boundaries. We investigated similarities differences soil physical chemical characteristics Sedgeland, Scrub Eucalyptus Forest sites around a large treeless area (Blakes Opening) situated densely forested Huon Valley southern Tasmania. In each community, risk was also assessed over 12 months using microclimate measures above-ground temperature humidity, water tables were monitored seasonally. Sedgeland soils upper layer organic (18–38 % C) sand rich (c. 75 mineral fraction), differed fundamentally from inorganic 5 C 55 sand). had much lower bulk density significantly concentration capital most nutrients (except C, N S) rootzone. Ordinations both rocks profiles discriminated Forest, with being intermediate. winter, higher than Scrub. However, has drier microclimate, which makes its fine fuels available to burn more frequently for longer period summer compared Forest. This confirmed by radiocarbon dating charcoal, showed that regular feature this environment throughout Holocene. The strong differentiation Sedgeland-Forest boundaries at Blakes Opening calls into prominent theory vegetation patterns region are shaped primarily landscape fires.

Language: Английский

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