The frequency of extreme weather events, such as drought, is increasing under climate change in some areas. Grassland ecosystems are extremely sensitive to drought. Here we sought to determine which vegetation types are the most vulnerable drought within the Xilinguole grasslands of Inner Mongolia and to establish methods to quantitatively evaluate the effects of different drought levels on grassland productivity and economic losses. Over the past 20 years, the total annual precipitation in the Xilinguole League decreased by 24–52%, resulting in a reduction in annual pasture yield of 31–237 kg/ha and a loss of livestock grazing capacity of 3–20 head/10 ha, causing 4–26 billion yuan in direct economic losses. Across the league, 78% of drought-induced direct economic losses were concentrated in ecologically vulnerable areas, including sandy and desert grasslands and typical grasslands at the northern end and in southwestern areas. Grassland net primary productivity (NPP) was sensitive to and significantly affected by drought. As the standardised precipitation evapotranspiration index (SPEI) drought level increased, NPP loss rate increased significantly by more than 20% for each drought level. The effects of increasing drought on NPP varied within grassland types, and the effects of a given drought level were different across grassland types. Typical grasslands suffered high losses at all drought stages. Meadow grasslands adjusted relatively well to drought as the rate of grassland NPP loss changed relatively slowly with increasing drought. Desert grasslands were less affected by light-to-moderate drought than by moderate-to-severe drought. This study provides a scientific basis for improving ecosystem resilience and drought prevention and management.

在某些地区，由于气候变化，干旱等极端天气事件的发生频率正在增加。草原生态系统对干旱极为敏感。在这里，我们试图确定哪种植被类型是内蒙古锡林郭勒草原内最脆弱的干旱，并建立定量评估不同干旱水平对草原生产力和经济损失的影响的方法。在过去的20年中，锡林郭勒盟的年总降水量减少了24–52％，导致牧场年产量减少31–237公斤/公顷，牲畜放牧能力降低了3–20头/ 10人造成直接经济损失42.6亿元。在整个联盟中，干旱造成的直接经济损失中有78％集中在生态脆弱地区，包括沙质和沙漠草原以及北端和西南地区的典型草原。草原净初级生产力（NPP）对干旱敏感并受到干旱的严重影响。随着标准降水蒸发蒸腾指数（SPEI）干旱水平的提高，每个干旱水平的NPP损失率均显着增加20％以上。干旱增加对NPP的影响在草地类型中有所不同，并且给定干旱水平对不同草地类型的影响是不同的。典型的草原在所有干旱阶段遭受的损失都很大。草地草原对干旱的适应相对较好，因为随着干旱的增加，草原NPP的损失速度变化相对缓慢。沙漠草原受轻度至中度干旱的影响要小于中度至重度干旱。