关键词: 蒙古高原, 草地生态系统, 干旱, 抵抗力, 恢复力

Abstract: Aims Mongolian Plateau grasslands are the core of the Eurasian grassland ecosystem and an important ecological barrier in northern China. Climate change has led to a significant increase in the intensity, frequency, and duration of drought events on the Mongolian Plateau. Therefore, quantitatively assessing the resistance and resilience of the Mongolian Plateau grasslands helps to deepen our understanding of grassland responses to climatic anomalies. However, few studies have explored the resilience and resistance of different grassland types on the Mongolian Plateau to consecutive droughts. Methods In this study, based on long-term series data of the Standardized Precipitation Evapotranspiration Index (SPEI) and Net Primary Productivity (NPP) from 2000 to 2020, we quantified the resistance and resilience of the Mongolian Plateau grassland ecosystem to consecutive droughts (1–4 years) and its spatiotemporal variations. Furthermore, we compared the differences in the responses of three main types of grasslands (meadow steppe, typical grassland, and desert steppe) to extreme and moderate droughts. Important findings Our results show that: (1) except for two consecutive years of drought, the resistance of grasslands under moderate drought is generally higher than that under extreme drought, but the opposite is true for resilience. (2) As the number of consecutive drought years increases, the resistance of grasslands under both extreme and moderate droughts shows a declining trend, but resilience shows an increasing trend under extreme drought and a decreasing trend under moderate drought. (3) Among the three different grassland types, meadow steppe has the highest resistance, followed by typical steppe and desert steppe. Conversely, desert steppe has the highest resilience, followed by meadow steppe. (4) Over time, the resistance of grasslands was higher in 2011–2020 than in 2001–2010, but with the opposite trend for resilience. With the increase in consecutive drought years, the resistance of the three types of grasslands shows a declining trend in both 2000–2010 and 2011–2020, but the resilience shows an increasing trend first (2000–2010) and then a decreasing trend (2011–2020). This study is of great significance for maintaining the important ecological barrier of the Mongolian Plateau, ensuring its ecological service functions, and promoting regional and global ecological security and sustainable development.

Key words: Mongolian Plateau, grassland ecosystem, drought, resistance, resilience