Increasing and widespread vulnerability of intact tropical rainforests to repeated droughts

Proceedings of the National Academy of Sciences, Journal Year: 2022, Volume and Issue: 119(37)

Published: Sept. 6, 2022

Intact tropical rainforests have been exposed to severe droughts in recent decades, which may threaten their integrity, ability sequester carbon, and capacity provide shelter for biodiversity. However, response remains uncertain due limited high-quality, long-term observations covering extensive areas. Here, we examined how the upper canopy of intact has responded drought events globally during past 3 decades. By developing a long pantropical time series (1992 2018) monthly radar satellite observations, show that repeated caused sustained decline signal 93%, 84%, 88% Americas, Africa, Asia, respectively. Sudden decreases were detected around 1997–1998, 2005, 2010, 2015 Americas; 1999–2000, 2004–2005, 2010–2011, Africa; 2006, Asia. Rainforests showed similar low resistance (the maintain predrought condition when occurs) across continents, but American consistently lowest resilience return after event). Moreover, while is decreasing, albeit weakly Africa forest not increased significantly. Our results therefore suggest withstand future limited. This negative implications climate change mitigation through forest-based solutions associated pledges made by countries under Paris Agreement.

Language: Английский

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Small and slow is safe: On the drought tolerance of tropical tree species

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(8), P. 2622 - 2638

Published: Jan. 10, 2022

Understanding how evolutionary history and the coordination between trait trade-off axes shape drought tolerance of trees is crucial to predict forest dynamics under climate change. Here, we compiled traits related fast-slow stature-recruitment in 601 tropical woody species explore their covariations phylogenetic signals. We found that xylem resistance embolism (P50) determines risk hydraulic failure, while functional significance leaf turgor loss point (TLP) relies on its with water use strategies. P50 TLP exhibit weak signals substantial variation within genera. closely associated axis: slow maintain functioning higher stress. both axes: small more resistant xylem. Lower phosphorus concentration xylem, which suggests a (nutrient drought) stress-tolerance syndrome tropics. Overall, our results imply (1) strong selective pressure forests, result from repeated adaptation taxa, (2) coordinated ecological strategies governing demography. These findings provide physiological basis interpret drought-induced shift toward slow-growing, smaller, denser-wooded observed tropics, implications for restoration programmes.

Language: Английский

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Forest fragmentation impacts the seasonality of Amazonian evergreen canopies

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Feb. 17, 2022

Predictions of the magnitude and timing leaf phenology in Amazonian forests remain highly controversial. Here, we use terrestrial LiDAR surveys every two weeks spanning wet dry seasons Central Amazonia to show that plant varies strongly across vertical strata old-growth forests, but is sensitive disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, find when maximum daily temperatures reached 35 °C latter part season, upper canopy large trees undisturbed lost material. contrast, understory greened up increased light availability driven by loss, alongside increases solar radiation, even during periods drier soil atmospheric conditions. However, persistently high edges exacerbated losses throughout whereas these light-rich environments was less dependent on altered structure. Our findings reveal a strong influence edge effects phenological controls Amazonia.

Language: Английский

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Experimental warming reduces ecosystem resistance and resilience to severe flooding in a wetland

Science Advances, Journal Year: 2022, Volume and Issue: 8(4)

Published: Jan. 26, 2022

Climate warming and extreme hydrological events are threatening the sustainability of wetlands across globe. However, whether climate will amplify or diminish impact flooding on wetland ecosystems is unknown. Here, we show that significantly reduced resistance resilience to a severe event via 6-year experiment. We first found rapidly altered plant community structure by increasing dominance low-canopy species. Then, showed vegetation productivity 72-cm event. Last, detected slower postflooding carbon processes, such as gross ecosystem productivity, soil respiration, methane emission, under treatment. Our results demonstrate how can destabilize function warming. These findings indicate an enhanced footprint in warmer climate.

Language: Английский

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Feedback in tropical forests of the Anthropocene

Global Change Biology, Journal Year: 2022, Volume and Issue: 28(17), P. 5041 - 5061

Published: June 30, 2022

Abstract Tropical forests are complex systems containing myriad interactions and feedbacks with their biotic abiotic environments, but as the world changes fast, future of these ecosystems becomes increasingly uncertain. In particular, global stressors may unbalance that stabilize tropical forests, allowing other to propel undesired in whole ecosystem. Here, we review scientific literature across various fields, compiling known environment, including climate, rainfall, aerosols, fire, soils, fauna, human activities. We identify 170 individual among 32 elements present a forest network, countless feedback loops emerge from different combinations interactions. illustrate our findings three cases involving urgent sustainability issues: (1) wildfires wetlands South America; (2) encroachment African savanna landscapes; (3) synergistic threats peatland Borneo. Our reveal an unexplored shape dynamics forests. The identified here can guide qualitative quantitative research on complexities societies manage nonlinear responses Anthropocene.

Language: Английский

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