NWIPB OpenIR
Differential responses of CO2 and latent heat fluxes to climatic anomalies on two alpine grasslands on the northeastern Qinghai-Tibetan Plateau
Li, Hongqin; Zhang, Fawei; Li, Jiexia; Guo, Xiaowei; Zhou, Huakun; Li, Yingnian
2023
Source PublicationSCIENCE OF THE TOTAL ENVIRONMENT
Volume900
AbstractDiscrete extreme heat events, deluges, and droughts will become more frequent and disproportionately affect the processes and functions of grassland ecosystems. Here, we compared the responses of CO2 and heat fluxes to natural extreme events in 2016 in a lower alpine meadow and neighboring upper shrubland on the northeastern Qinghai-Tibetan Plateau. Unlike insensitive sensible heat flux, latent heat flux (LE) increased by 21.8 % in the meadow and by 56.4 % in the shrubland during a dry period and subsequent compound hot-dry period in August. Changes (A, data for 2016 minus the corresponding means from other years) in the heat flux at both sites were determined by changes in solar radiation (ASwin), as sufficient soil moisture was available. ALE was more sensitive to ASwin in the open-canopy shrubland, reflecting its greater capacity for evaporative cooling to buffer climate anomalies. CO2 fluxes responded weakly to extreme wet or dry events but strongly when those events were accompanied by exceptional heat. During single or compound hot events, the mean changes in total ecosystem respiration (ATER) increased by about 30 % in both grasslands, although ATER was more sensitive to changes in the topsoil temperature in the more productive meadow than in the shrubland. The mean changes in gross primary productivity (AGPP) fluctuated by <10 % in the warmer meadow but increased by 29.3 % in the cooler shrubland relative to the respective baseline, probably because of the differences in canopy structure and root depth and the consequent high-temperature stress on vegetation photosynthesis. The changes in net ecosystem CO2 exchange (ANEE) were significantly related to ATER in the meadow and increased by 55.8 %, whereas ANEE was controlled mainly by AGPP in the shrubland and decreased by 22.4 %. Overall, both alpine grasslands were resistant to rainfall anomalies but susceptible to exceptional warmth, with the differential re-sponses being ascribed to canopy structure and root depth. Our results provide helpful insights based on which the carbon sequestration and water-holding functions of alpine grasslands during future climate change can be predicted.
Indexed BySCIE
Document Type期刊论文
Identifierhttp://210.75.249.4/handle/363003/61602
Collection中国科学院西北高原生物研究所
Recommended Citation
GB/T 7714
Li, Hongqin,Zhang, Fawei,Li, Jiexia,et al. Differential responses of CO2 and latent heat fluxes to climatic anomalies on two alpine grasslands on the northeastern Qinghai-Tibetan Plateau[J]. SCIENCE OF THE TOTAL ENVIRONMENT,2023,900.
APA Li, Hongqin,Zhang, Fawei,Li, Jiexia,Guo, Xiaowei,Zhou, Huakun,&Li, Yingnian.(2023).Differential responses of CO2 and latent heat fluxes to climatic anomalies on two alpine grasslands on the northeastern Qinghai-Tibetan Plateau.SCIENCE OF THE TOTAL ENVIRONMENT,900.
MLA Li, Hongqin,et al."Differential responses of CO2 and latent heat fluxes to climatic anomalies on two alpine grasslands on the northeastern Qinghai-Tibetan Plateau".SCIENCE OF THE TOTAL ENVIRONMENT 900(2023).
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