State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing, China.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China.
Glob Chang Biol. 2023 Jul;29(13):3562-3574. doi: 10.1111/gcb.16620. Epub 2023 Feb 6.
Recovery time, the time it takes for ecosystems to return to normal states after experiencing droughts, is critical for assessing the response of ecosystems to droughts; however, the spatial dominant factors determining recovery time are poorly understood. We identify the global patterns of terrestrial ecosystem recovery time based on remote sensed vegetation indices, analyse the affecting factors of recovery time using random forest regression model, and determine the spatial distribution of the dominant factors of recovery time based on partial correlation. The results show that the global average recovery time is approximately 3.3 months, and that the longest recovery time occurs in mid-latitude drylands. Analysis of affecting factors of recovery time suggests that the most important environmental factor affecting recovery time is soil moisture during the recovery period, followed by temperature and vapour pressure deficit (VPD). Recovery time shortens with increasing soil moisture and prolongs with increasing VPD; however, the response of recovery time to temperature is nonmonotonic, with colder or hotter temperatures leading to longer recovery time. Soil moisture dominates the drought recovery time over 58.4% of the assessed land area, mostly in the mid-latitudes. The concern is that soil moisture is projected to decline in more than 65% regions in the future, which will lengthen the drought recovery time and exacerbate drought impacts on terrestrial ecosystems, especially in southwestern United States, the Mediterranean region and southern Africa. Our research provides methodological insights for quantifying recovery time and spatially identifies dominant factors of recovery time, improving our understanding of ecosystem response to drought.
恢复时间是指生态系统经历干旱后恢复到正常状态所需的时间，对于评估生态系统对干旱的响应至关重要；然而，确定恢复时间的空间主导因素仍不清楚。我们基于遥感植被指数确定了陆地生态系统恢复时间的全球格局，使用随机森林回归模型分析了恢复时间的影响因素，并基于偏相关确定了恢复时间的主导因素的空间分布。结果表明，全球平均恢复时间约为 3.3 个月，中纬度干旱地区的恢复时间最长。对恢复时间影响因素的分析表明，影响恢复时间的最重要环境因素是恢复期间的土壤湿度，其次是温度和蒸气压亏缺（VPD）。随着土壤湿度的增加，恢复时间缩短，随着 VPD 的增加，恢复时间延长；然而，恢复时间对温度的响应是非单调的，较冷或较热的温度会导致更长的恢复时间。土壤湿度主导着 58.4%以上评估土地面积的干旱恢复时间，主要集中在中纬度地区。令人担忧的是，未来超过 65%的地区预计土壤湿度将会下降，这将延长干旱的恢复时间，并加剧干旱对陆地生态系统的影响，特别是在美国西南部、地中海地区和南部非洲。我们的研究为量化恢复时间提供了方法学见解，并在空间上确定了恢复时间的主导因素，从而提高了我们对生态系统对干旱响应的理解。
