Li Ruonan, Zheng Hua, O'Connor Patrick, Xu Huashan, Li Yunkai, Lu Fei, Robinson Brian E, Ouyang Zhiyun, Hai Yue, Daily Gretchen C
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Adv. 2021 Mar 31;7(14). doi: 10.1126/sciadv.abf8650. Print 2021 Mar.
In response to extreme societal consequences of ecosystem degradation and climate change, attention to ecological restoration is increasing globally. In China, investments in restoration exceeded USD 378.5 billion over the past decade. However, restoration programs are experiments that can cause marked unintended consequences, with trade-offs across space and time that have undergone little empirical examination. We quantified the long-term effects of large-scale afforestation for soil erosion and sandstorm prevention in semiarid China. We found that soil erosion was notably reduced by afforestation but surface runoff declined significantly, after a time lag of 18 years, limiting overall benefit. While forest area also increased, forest quality declined, interacting with reduced surface water runoff. Crucially, increased forest water consumption accelerated downstream groundwater depletion, thus intensifying conflicts over water use. The time lags and spatial trade-offs revealed by this case study provide critical lessons for large-scale restoration programs globally.
鉴于生态系统退化和气候变化带来的极端社会后果，全球对生态恢复的关注与日俱增。在中国，过去十年间用于恢复的投资超过3785亿美元。然而，恢复项目是一些可能会导致显著意外后果的试验，存在着时空权衡，而这方面几乎没有经过实证检验。我们对中国半干旱地区大规模造林以防治土壤侵蚀和沙尘暴的长期影响进行了量化。我们发现，造林显著减少了土壤侵蚀，但地表径流在18年的时间滞后后显著下降，限制了总体效益。虽然森林面积也有所增加，但森林质量下降，与地表径流减少相互作用。至关重要的是，森林耗水量增加加速了下游地下水枯竭，从而加剧了用水冲突。本案例研究揭示的时间滞后和空间权衡为全球大规模恢复项目提供了重要教训。
