摘要
高寒草地生态系统是青藏高原主要生态系统类型之一,其结构和功能对全球变化敏感.过去几十年,随着气候变化与人类活动加剧,高寒草地生态系统结构和功能发生了巨大变化,然而其变化的自然及人为相对贡献率存在较大争议.本研究基于优化的模型差值法评估了1990~2013年青藏高原高寒草地变化的人为相对贡献率.研究结果表明,这一时期青藏高原高寒草地生产力显著增加,人类活动主导了草地生态系统净初级生产力的变化,人为相对贡献率达到74.0%,人类活动主导草地生产力增加的面积占比大于主导草地生产力减少的面积占比,青藏高原草地可能已由过度利用转变为适度保护,但其特征呈现复杂性. 2000年后人类活动影响急剧增强,表明同期实施的大型生态恢复工程可能增加了高寒草地生产力.空间结果表明,两个时期相比有36.7%的草地生产力变化由气候变化主导转为人类活动主导,其中主导草地生产力减少是增加的两倍以上.随着我国生态文明建设的不断推进,青藏高原高寒草地生态功能总体上开始呈恢复趋势,但人类活动主导草地生产力减少的区域也在增加,该区域可能已趋于人地关系发生转变的临界点.因此,退化草地的恢复与治理仍是青藏高原生态安全屏障建设的重要支点,青藏高原草地适应性管理已刻不容缓.
Alpine grasslands are one of the major ecosystem types on the Qinghai-Tibetan Plateau. In the past decades, the ecological structure and function of alpine grasslands have undergone great changes with intensified climate change and human activities. However, the relative contributions of natural and human factors to such changes are controversial. Based on the optimized residual method, this study evaluated the relative anthropogenic contribution to the changes in alpine grasslands on the Qinghai-Tibetan Plateau in the past twenty years(1990-2013). The Lund-potsdam-jena model(LPJ), Integrated Biosphere Simulator model(IBIS) and Terrestrial ecosystem model(TEM) were selected to simulate grassland productivity driven by climate factors. We found that the temperature on the plateau was on the rise at a rate of about 0.5°C per decade. Precipitation increased slightly, but with a large spatial difference. The population of the Tibetan Plateau increased sharply during the study period. During the two score years(1990-2013), the productivity of alpine grasslands on the Qinghai-Tibetan Plateau increased greatly, mainly(up to 74.0%) contributed by human activities. Where the change was dominated by human activities, the area with increased grassland net primary product(NPP) was greater than that with decreased NPP, indicating that the over-utilization of alpine grasslands has been effectively contained and reversed into moderate protection. For five out of the first ten years(1990-1999), human activities dominated the change of alpine grasslands(relative anthropogenic contribution around 60.1%), the NPP increased for 3 years and decreased for 2 years.After 2000, the impact of human activities increased sharply(up to 84.6%) and the anthropogenic dominating area expanded substantially, indicating that the large ecological restoration project implemented may have increased the productivity of alpine grasslands in the same period(9 out of 13 years for NPP increase). Spatial analyses comparing the two periods showed that 36.7% of areas with changed grassland NPP was dominated first by climate change and then by human activities, among which 10.1% had increased NPP and 26.6% had decreased NPP. In one word, the Qinghai-Tibetan Plateau may be approaching the turning point of the Environmental Kuznets Curve. Therefore, with further strengthened construction of ecological civilization, the ecological function of alpine grasslands would continue to be improved on the Plateau. However, we should also pay attention to the ever larger areas of human activity-induced NPP decrease. Therefore,the restoration and treatment of degraded grasslands is still pivotal to the construction of ecological security barriers and adaptative ecosystem management of grasslands on the Qinghai-Tibetan Plateau.
作者
陈槐
鞠佩君
张江
王元云
朱求安
颜亮
康晓明
何奕忻
曾源
郝彦宾
王艳芬
Huai Chen;Peijun Ju;Jiang Zhang;Yuanyun Wang;Qiu'an Zhu;Liang Yan;Xiaoming Kang;Yixin He;Yuan Zeng;Yanbin Hao;Yanfen Wang(Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;Center for Excellence in Tibetan Plateau Earth Sciences,Chinese Academy of Sciences,Beijing 100101,China;Center for Ecological Forecasting and Global Change,College of Forestry,Northwest A&F University,Yangling 712100,China;Institute of Wetland Research,Chinese Academy of Forestry,Beijing 100091,China;Institute of Remote Sensing and Digital Earth,Chinese Academy of Sciences,Beijing 100094,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2020年第22期2406-2418,共13页
Chinese Science Bulletin
基金
第二次青藏高原综合科学考察研究项目(2019QZKK0304)
中国科学院A类战略性先导科技专项(XDA2005010404)
国家重点研发计划(2016YFC0501804)资助。
关键词
植被指数
净初级生产力
气候变化
人类活动
normalized difference vegetation index(NDVI)
net primary product(NPP)
climate change
human activities
