Premium
Drought and heat wave impacts on grassland carbon cycling across hierarchical levels
Author(s) -
Li Linfeng,
Zheng Zhenzhen,
Biederman Joel A.,
Qian Ruyan,
Ran Qinwei,
Zhang Biao,
Xu Cong,
Wang Fang,
Zhou Shutong,
Che Rongxiao,
Dong Junfu,
Xu Zhihong,
Cui Xiaoyong,
Hao Yanbin,
Wang Yanfen
Publication year - 2021
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13767
Subject(s) - ecosystem , grassland , environmental science , carbon cycle , biomass (ecology) , photosynthesis , atmospheric sciences , grassland ecosystem , agronomy , nutrient cycle , climate change , carbon sink , sink (geography) , cycling , carbon sequestration , nutrient , carbon dioxide , ecology , biology , botany , geography , geology , forestry , cartography
Droughts and heat waves are increasing in magnitude and frequency, altering the carbon cycle. However, understanding of the underlying response mechanisms remains poor, especially for the combination (hot drought). We conducted a 4‐year field experiment to examine both individual and interactive effects of drought and heat wave on carbon cycling of a semiarid grassland across individual, functional group, community and ecosystem levels. Drought did not change below‐ground biomass (BGB) or above‐ground biomass (AGB) due to compensation effects between grass and non‐grass functional groups. However, consistently decreased BGB under heat waves limited such compensation effects, resulting in reduced AGB. Ecosystem CO 2 fluxes were suppressed by droughts, attributed to stomatal closure‐induced reductions in leaf photosynthesis and decreased AGB of grasses, while CO 2 fluxes were little affected by heat waves. Overall the hot drought produced the lowest leaf photosynthesis, AGB and ecosystem CO 2 fluxes although the interactions between heat wave and drought were usually not significant. Our results highlight that the functional group compensatory effects that maintain community‐level AGB rely on feedback of root system responses, and that plant adjustments at the individual level, together with shifts in composition at the functional group level, co‐regulate ecosystem carbon sink strength under climate extremes.