Excessive Afforestation and Soil Drying on China's Loess Plateau
Excessive Afforestation and Soil Drying on China's Loess Plateau
复制标题
DOI：
10.1002/2017jg004038
复制
发表时间：
2017-04
期刊：
影响因子：
--
通讯作者：
Shui-Chang Zhang;Dawen Yang;Yuting Yang;S. Piao;Hanbo Yang;H. Lei;B. Fu
中科院分区：
文献类型：
--
作者：
Shui-Chang Zhang;Dawen Yang;Yuting Yang;S. Piao;Hanbo Yang;H. Lei;B. Fu
造林和毁林作为人类对植被的干扰，对生态水文过程产生深远影响，影响水和碳循环以及生态系统的可持续性。 1999年以来，我国黄土高原实施了“退耕还林工程”等大规模植被恢复活动。然而，负面的生态水文后果，包括径流下降和土壤干燥已经出现。本文基于生态水文模型估算了黄土高原的平衡植被覆盖度，并评估了过去十年平衡下的水平衡和实际植被覆盖度。结果表明，黄土高原许多地区，特别是中东地区，目前的植被覆盖度（平均0.48）已经超过了气候定义的平衡植被覆盖度（平均0.43）。这表明广泛的过度种植，被发现是该地区土壤干燥的主要原因。此外，由于大气水供应（即降水）减少和大气需水量（即潜在蒸散量）增加，在未来（即2011-2050年）气候情景下，平衡植被覆盖和土壤湿度均趋于减少。我们的研究结果表明，黄土高原的进一步植被恢复应谨慎实施。为了维持该地区可持续的生态水文环境，迫切需要一个植被恢复阈值来指导未来的植被恢复活动。
Afforestation and deforestation as human disturbances to vegetation have profound impacts on ecohydrological processes influencing both water and carbon cycles and ecosystem sustainability. Since 1999, large‐scale revegetation activities such as “Grain‐to‐Green Program” have been implemented across China's Loess Plateau. However, negative ecohydrological consequences, including streamflow decline and soil drying have emerged. Here we estimate the equilibrium vegetation cover over the Loess Plateau based on an ecohydrological model and assess the water balance under the equilibrium and actual vegetation cover over the past decade. Results show that the current vegetation cover (0.48 on average) has already exceeded the climate‐defined equilibrium vegetation cover (0.43 on average) in many parts of the Loess Plateau, especially in the middle‐to‐east regions. This indicates a widespread overplanting, which is found to primarily responsible for soil drying in the area. Additionally, both the equilibrium vegetation cover and soil moisture tend to decrease under future (i.e., 2011–2050) climate scenarios due to declined atmospheric water supply (i.e., precipitation) and increased atmospheric water demand (i.e., potential evapotranspiration). Our findings suggest that further revegetation on the Loess Plateau should be applied with caution. To maintain a sustainable ecohydrological environment in the region, a revegetation threshold is urgently needed to guide future revegetation activities.