关键词: 生态系统稳定性, 植物功能性状, 抵抗力, 温带草原, 叶经济谱

Abstract: The frequency and intensity of extreme droughts are increasing and are predicted to be more severe in the coming decades. Clarifying the reasons for species-specific resistance to extreme drought is vital for predicting changes in community structure and ecosystem functioning. While the ‘slow-fast’ economics spectrum is widely used to explain interspecific variations in ecological strategies, community assembly and ecosystem functioning, its role in driving plant resistance to extreme drought is under debate. We examined the relationship between the resistance of plants to extreme drought (60% reduction in growing season precipitation) and the ‘slow-fast’ economics spectrum across 13 species in a temperate steppe. We found significant interspecific variations in the resistance of plants to extreme drought, with the dominant grass, Leymus chinensis, showing the strongest resistance. Extreme drought resistance was negatively associated with the slow-fast continuum, with higher resistance of slow-growing species than the fast-growing ones. Chemical traits were more important than morphological traits in predicting plant resistance to extreme drought. Our results provide direct evidence for the strong association between the plant economics spectrum and species-level resistance to extreme drought and call for more attention to species with a fast strategy due to their higher vulnerability to extreme drought.

Key words: ecosystem stability, plant functional traits, resistance, semiarid grassland leaf economic spectrum