Assessing drought risk of grassland ecosystem in Hulunbuir, China

Hulunbuir, a globally renowned grassland and critical ecological security barrier in northern China, faces increasing drought risks under climate change and intensifying human activities. To assess the drought risk of the Hulunbuir grassland, this study developed an innovative drought risk assessment framework based on the hazard, vulnerability, and exposure dimensions, with particular emphasis on the impact of human activities and water conservation service. By using multi-source data during growing seasons from 2000 to 2022, the research quantitatively evaluated the drought risk and explored its underlying mechanisms. Approximately 29.4 % of the Hulunbuir grassland was classified as high or moderately high risk, primarily concentrated in the western areas, including New Barag Right Banner, Manzhouli, Hailar and the northern New Barag Left Banner (R > 0.61). In contrast, the eastern part of Hulunbuir experienced moderately low to low drought risk (R ≤ 0.37), showing a distinct zonal distribution from west to east. This study further explores the complexity of grassland drought vulnerability and the regional divergence in drought risk causation, highlighting the critical role of human activities and ecosystem services in risk assessment. The findings provide essential insights for policymakers to develop targeted drought risk management strategies. Region-specific measures, including enhanced monitoring, sustainable grazing practices, and ecological compensation mechanisms, are proposed to enhance grassland resilience and promote sustainable development.