Asymmetric effects of diurnal warming on carbon allocation to leaves of marsh wetlands on the Tibetan Plateau

Abstract

ABSTRACT Using MODIS leaf area index and meteorological data from 2000 to 2020, this study analyzed the variations in carbon allocation to leaves (C leaf) of marsh during the leaf green-up period and their response to climate change across the TP based on partial correlation and linear regression analysis methods. The regionally averaged C leaf of marsh showed an increasing trend during the leaf green-up period from 2000 to 2020. Diurnal warming has asymmetric effects on C leaf of marsh during different stages of the leaf green-up period. During the early leaf green-up period, warming preseason daytime temperature significantly reduced C leaf in the southwestern region, while warming preseason daytime and night-time temperatures increased C leaf in the central region. During the late leaf green-up period, preseason temperatures exerted significantly positive and negative effects on C leaf in the southwestern and central regions, respectively. During the early leaf green-up period, preseason precipitation increases significantly enhanced C leaf in the southwestern region, but decreased C leaf in the central region. This study highlights the distinct impacts of climatic change on C leaf during different stages of the leaf green-up period and indicates that the asymmetric effects of diurnal warming should be considered in simulations of marsh carbon allocation in the future.