Changes in above- versus belowground biomass distribution in permafrost regions in response to climate warming

Hanbo Yun, Philippe Ciais, Qing Zhu, Deliang Chen, Constantin M. Zohner*, Jing Tang, Yang Qu, Hao Zhou, Joshua Schimel, Peng Zhu, Ming Shao, Jens Hesselbjerg Christensen, Qingbai Wu*, Anping Chen, Bo Elberling*

*Corresponding author af dette arbejde

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Abstract

Permafrost regions contain approximately half of the carbon stored in land ecosystems and have warmed at least twice as much as any other biome. This warming has influenced vegetation activity, leading to changes in plant composition, physiology, and biomass storage in aboveground and belowground components, ultimately impacting ecosystem carbon balance. Yet, little is known about the causes and magnitude of long-term changes in the above- to belowground biomass ratio of plants (η). Here, we analyzed η values using 3,013 plots and 26,337 species-specific measurements across eight sites on the Tibetan Plateau from 1995 to 2021. Our analysis revealed distinct temporal trends in η for three vegetation types: a 17% increase in alpine wetlands, and a decrease of 26% and 48% in alpine meadows and alpine steppes, respectively. These trends were primarily driven by temperature-induced growth preferences rather than shifts in plant species composition. Our findings indicate that in wetter ecosystems, climate warming promotes aboveground plant growth, while in drier ecosystems, such as alpine meadows and alpine steppes, plants allocate more biomass belowground. Furthermore, we observed a threefold strengthening of the warming effect on η over the past 27 y. Soil moisture was found to modulate the sensitivity of η to soil temperature in alpine meadows and alpine steppes, but not in alpine wetlands. Our results contribute to a better understanding of the processes driving the response of biomass distribution to climate warming, which is crucial for predicting the future carbon trajectory of permafrost ecosystems and climate feedback.
OriginalsprogEngelsk
Artikelnummere2314036121
TidsskriftProceedings of the National Academy of Sciences of the United States of America
Vol/bind121
Udgave nummer25
Antal sider10
ISSN0027-8424
DOI
StatusUdgivet - 2024

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CENPERMOA[2024]

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