Author(s): Minglei Yao; Yanyan Cheng; Xiaogang He; Tao Yu

Linked Author(s):

Keywords: Climate change; Ecosystem-scale water use efficiency; Plant-scale water use efficiency; Tibetan Plateau; Vegetation carbon-water flux

Abstract: Studying the relationship and coupling laws between carbon sequestration and water consumption in the vegetation of the Tibetan Plateau is crucial for addressing the potential conflicts between carbon sink and water yield functions on the plateau. By employing the Community Land Model version 5 (CLM5), adapted for the Tibetan Plateau, and a machine learning approach based on Boosted Regression Tree (BRT), this research simulated and analyzed the variations in water use efficiency (WUE) of different vegetation types at various scales under different climate change scenarios. The findings are as follows: (1) Precipitation is the primary control factor for the variation of Plant-scale Water Use Efficiency (PWUE) in woodlands and grasslands. Under the background of climate change, PWUE in woodlands mainly decreases with increasing precipitation, while in grasslands, it mainly increases. This leads to a positive impact of climate change on grassland PWUE (3.0% to 4.3%) and a negative impact on forest PWUE (-3.7% to -9.1%). (2) Climate change has a significant negative effect on Ecosystem-scale Water Use Efficiency (WUE) in woodlands (-0.050 to -0.054 gC kg-1 H2O), and a significant positive effect on grasslands (0.071 to 0.104 gC kg-1 H2O). The main reason is that climate change reduces carbon use efficiency in woodlands (29% to 30%) while significantly enhancing it in grasslands (102% to 256%). Overall, climate change increases the future WUE of overall vegetation (0.055 to 0.086 gC kg-1 H2O), mitigating the potential conflict between carbon sink and water yield functions on the Tibetan Plateau.

DOI: https://doi.org/10.3850/iahr-hic2483430201-240

Year: 2024