Detection of drought effects on photosynthetic stability of vegetation on the Loess Plateau based on solar-induced chlorophyll fluorescence

doi:10.17521/cjpe.2023.0265

Abstract

Abstract:

Aims The Loess Plateau stands as one of China’s most susceptible regions to meteorological drought, a vulnerability exacerbated in recent years by the backdrop of climate warming. As meteorological droughts show a rising trend, investigating the capacity of vegetation to withstand and recover from drought stress becomes paramount. Understanding the resilience and resistance of vegetation’s photosynthetic physiological processes to drought is crucial for comprehending how vegetation responds to environmental shifts and for forecasting the future trajectory of vegetation development in the area.
Methods Utilizing the solar-induced chlorophyll fluorescence Global SIF dataset based on OCO-2 (GOSIF) products alongside temperature and standardized precipitation evapotranspiration index (SPEI) data, this study aims to investigate the impact of drought on the spatial and temporal stability of photosynthesis across various vegetation types and climate zones on the Loess Plateau employing the multiple linear autoregressive model.
Important findings The study revealed a linear relationship between vegetation photosynthetic resilience and the severity of drought experienced on the Loess Plateau. Vegetation photosynthetic resilience weakens in the order of mild, moderate, and severe drought. The relationship between vegetation photosynthetic resistance and drought severity exhibited a nonlinear pattern, with resistance declining from severe to mild and moderate drought. Vegetation photosynthesis on the Loess Plateau displayed insensitivity to temperature variations. Comparison across climatic zones highlighted that in arid regions, vegetation photosynthetic resilience declined with escalating drought severity, whereas semi-arid zones demonstrated relatively stable resilience. In semi-humid regions, vegetation photosynthetic resilience decreased in the order of severe, mild, and moderate droughts. Among vegetation types, forests demonstrated the highest levels of both resilience and resistance. These findings contribute significantly to our understanding of the regional vegetation stability in the Loess Plateau under the background of climate changes, thereby guiding the ecological restoration and management efforts in the region.

Key words: solar-induced chlorophyll fluorescence, vegetation photosynthesis, Loess Plateau, drought, resilience, resistance

LIU Ke-Yan, HAN Lu, SONG Wu-Ye, ZHANG Chu-Rui, HU Xu, XU Hang, CHEN Li-Xin. Detection of drought effects on photosynthetic stability of vegetation on the Loess Plateau based on solar-induced chlorophyll fluorescence[J]. Chin J Plant Ecol, 2025, 49(3): 415-431.

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干旱等级 Drought classification	SPEI值 SPEI value
轻度干旱 Mild drought	-1.0 < SPEI ≤ -0.5
中度干旱 Moderate drought	-1.5 < SPEI ≤ -1.0
重度干旱 Severe drought	SPEI ≤ -1.5

干旱等级 Drought classification	SPEI值 SPEI value
轻度干旱 Mild drought	-1.0 < SPEI ≤ -0.5
中度干旱 Moderate drought	-1.5 < SPEI ≤ -1.0
重度干旱 Severe drought	SPEI ≤ -1.5

系数 Coefficient	变化幅度的解释 Explanation of the magnitude of change	正负符号的解释 Interpretation of positive and negative signs
α (Y_t_-1的系数) α (coefficients for Y_t_-1)	绝对值在0到1之间代表植被恢复平衡, 绝对值越大表明复原力越低。绝对值大于1, 植被将以振荡的方式恢复平衡 Absolute values between 0 and 1 represent systems returning to equilibrium, with large absolute values indicating a low resilience. Absolute values are larger than 1, the system returns to equilibrium in an oscillating way	正异常与之前的异常相似; 负异常与之前的异常相似, 但符号相反 Positive anomalies are similar to the previous anomaly. Negative anomalies are similar to the previous anomaly, but with the opposite sign
β (SPEI_t的系数)和σ (T_t的系数) β (coefficients for SPEI_t) and σ (coefficients for T_t)	绝对值越大表明植被对干旱/温度异常越敏感, 即植被对短期干旱/温度反常的抵抗力越小 Large absolute values indicate a low resistance to droughts/ temperature anomalies	正值表示更湿润条件下或更高的温度下植被光合作用增加; 负值表示更润湿条件下或更高的温度下植被光合作用下降 Positive values indicate wetter conditions or higher temperatures induce the increase of solar-induced chlorophyll fluorescence (SIF). Negative values indicate wetter conditions or higher temperatures induce the decrease of SIF

系数 Coefficient	变化幅度的解释 Explanation of the magnitude of change	正负符号的解释 Interpretation of positive and negative signs
α (Y_t_-1的系数) α (coefficients for Y_t_-1)	绝对值在0到1之间代表植被恢复平衡, 绝对值越大表明复原力越低。绝对值大于1, 植被将以振荡的方式恢复平衡 Absolute values between 0 and 1 represent systems returning to equilibrium, with large absolute values indicating a low resilience. Absolute values are larger than 1, the system returns to equilibrium in an oscillating way	正异常与之前的异常相似; 负异常与之前的异常相似, 但符号相反 Positive anomalies are similar to the previous anomaly. Negative anomalies are similar to the previous anomaly, but with the opposite sign
β (SPEI_t的系数)和σ (T_t的系数) β (coefficients for SPEI_t) and σ (coefficients for T_t)	绝对值越大表明植被对干旱/温度异常越敏感, 即植被对短期干旱/温度反常的抵抗力越小 Large absolute values indicate a low resistance to droughts/ temperature anomalies	正值表示更湿润条件下或更高的温度下植被光合作用增加; 负值表示更润湿条件下或更高的温度下植被光合作用下降 Positive values indicate wetter conditions or higher temperatures induce the increase of solar-induced chlorophyll fluorescence (SIF). Negative values indicate wetter conditions or higher temperatures induce the decrease of SIF