Yan Yingjie, Xu Chong, Hautier Yann, Wang Hongqiang, Ke Yuguang, Wu Honghui, Wang Jinsong, Cheng Changjin, Zuo Xiaoan, Luo Wentao, Smith Melinda D, Knapp Alan K, Collins Scott L, Yu Qiang
School of Grassland Science, Beijing Forestry University, Beijing, China.
State Key Laboratory of Efficient Utilization of Arid and Semi-Arid Arable Land in Northern China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China.
Glob Chang Biol. 2025 Jun;31(6):e70303. doi: 10.1111/gcb.70303.
Ecological stability plays a crucial role in determining the sustainability of ecosystem functioning and nature's contribution to people. Although the disruptive effects of extreme drought on ecosystem structure and functions are widely recognized, their effect on the stability of above- and belowground productivity remains understudied. We assessed the effects of drought on ecosystem stability using a 3-year drought experiment established in six Eurasian steppe grasslands. The treatments imposed included ambient precipitation, chronic drought (66% reduction in precipitation throughout the growing season), and intense drought (complete exclusion of precipitation for two months during the growing season). We found that drought, irrespective of how it was imposed, reduced the stability of aboveground net primary productivity (ANPP) but had little impact on belowground net primary productivity (BNPP) stability. Reduced ANPP stability under drought was primarily attributed to changes in subordinate species stability, with mean annual precipitation (MAP) and its variability, historical drought frequency, and the aridity index (AI) also influencing responses to extreme drought. In contrast, BNPP stability was not related to any community factor investigated, but it was influenced by MAP variability and AI. Our findings that above- and belowground productivity stability in grasslands are differentially sensitive to multi-year extreme drought under both common (MAP and AI) as well as unique drivers (plant community changes) highlight the complexity of predicting carbon cycle dynamics as hydrological extremes become more severe.
生态稳定性在决定生态系统功能的可持续性以及自然对人类的贡献方面起着至关重要的作用。尽管极端干旱对生态系统结构和功能的破坏作用已得到广泛认可，但其对地上和地下生产力稳定性的影响仍未得到充分研究。我们利用在六个欧亚草原建立的为期三年的干旱实验，评估了干旱对生态系统稳定性的影响。实施的处理包括正常降水、长期干旱（整个生长季节降水量减少66%）和严重干旱（生长季节中有两个月完全不降水）。我们发现，无论干旱是如何施加的，它都会降低地上净初级生产力（ANPP）的稳定性，但对地下净初级生产力（BNPP）的稳定性影响很小。干旱条件下ANPP稳定性的降低主要归因于从属物种稳定性的变化，年平均降水量（MAP）及其变异性、历史干旱频率和干旱指数（AI）也会影响对极端干旱的响应。相比之下，BNPP稳定性与所研究的任何群落因素均无关联，但受MAP变异性和AI的影响。我们的研究结果表明，在常见驱动因素（MAP和AI）以及独特驱动因素（植物群落变化）作用下，草原地上和地下生产力稳定性对多年极端干旱的敏感性存在差异，这凸显了随着水文极端事件变得更加严重，预测碳循环动态的复杂性。
