摘要
高寒生态系统对全球变化非常敏感,以青藏高原腹地的长江黄河源区为研究区域,利用多期遥感TM数据和生态样带调查数据,提出生态综合指数方法.应用土壤结构、组成与水理特性等物理指标和土壤化学性质与养分含量指标,系统分析了青藏高原典型寒冻土壤如钙积寒性干旱土、简育寒性干旱土、草毡寒冻雏形土以及简育寒冻雏形土等对高寒生态系统变化的响应特征.结果表明:随着气候变化,主要高寒生态系统如高寒草甸、高寒草原以及高寒沼泽草甸等显著退化,寒冻土壤表层呈现明显粗粝化,草毡寒冻雏形土以及简育寒冻雏形土表层土壤细粒物质流失38.7%,土壤孔隙度和容重增加;高寒草甸土壤表层饱和导水率随综合生态指标值降低而急剧增大,当植被覆盖度<50%以后,土壤表层水分集聚现象不再存在,高寒草原土壤饱和导水率变化不明显;高寒草甸与高寒草原土壤的有机质和全氮含量均随生态指数减少而分别呈现抛物线和指数曲线形式减少.随着气候变暖和人类活动干扰的加剧,高寒草地生态系统变化将可能导致寒冻土壤环境持续退化并对高原草地碳循环产生重要的影响.
The high-cold ecosystem on the Tibetan Plateau is very sensitive to the changes of global climate. The hinterland of the Tibetan Plateau, i. e. , the source regions of the Yellow River and the Yangtze River, is selected as the target region. Using the data frequently collected from remote sensing technologies and the investigation data of ecosystem belts, it is systematically analyzed that the response features of the typical high-cold frozen earth on the Tibetan Plateau （e. g. cold arid earth of calcium sedimentary, simply cultivated cold arid earth, frozen embryonic earth of grassland and simply cultivated earth） to the change of high-cold ecosystem by using the ecological comprehe＇nsive index （including physical index： the soil structure, components and hydraulic features; chemical features of soil and the content of nutrient）. The result shows that the main high-cold ecosystem （high-cold meadow, high-cold steppe and high-cold marsh grassland） is seriously degrading climate change. The topsoil of high-cold earth idently coarsely granulated, 38.7% of the tiny-grain topsoil of grassland frozen embryonic earth and simply cultivated earth is lost, and the degree of small opening and the volume weight of the soil increases. The saturated hydraulic conductivity of the high-cold grassy marshland soil increases drastically with the decrease of comprehensive ecological index. The moisture gathering phenomenon on the topsoil of high-cold grassland does not exist any more when the vegetation coverage rate is below 50%, and the saturated hydraulic conductivity on the topsoil of high-cold grassland varies in a narrow range. The content of whole nitrogen and organic matter contained in the soil of high-cold meadow and high-cold steppe decreases like the form of parabola and exponential curve. With the future climate change and with the interference of human activities, the change of the ecosystem on the Tibetan Plateau will lead to continuous degradation of the high-cold frozen earth environment and produce a significant influence on the carbon cycle.
出处
《冰川冻土》
CSCD
北大核心
2006年第5期633-641,共9页
Journal of Glaciology and Geocryology
基金
中国科学院"百人计划"项目(2004年)
国家自然科学基金项目(90511003)
国家重点基础研究发展规划项目(2003CB415201)资助
关键词
高寒生态系统
气候变化响应
寒冻土壤
变化趋势
high-cold ecosystem
response to climatic change
frozen soil
changing tendency
作者简介
王一博（1970-）,男,甘肃会宁人,2004年在兰州大学获硕士学位, 现为博士研究生,主要从事寒区旱区环境研究和学习. E-mail：yibo_w@sina.com;
王根绪, 通讯作者 E-mail：gxwang@lzb.ac.cn
