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作 者 ：冯永忠*,杨改河,王得祥,胡良温

期 刊 ：生态学报 2009年 29卷 1期 页码：492~498

关键词：江河源区；草地；生态压力；

Keywords:sources of Yangtze River, Yellow River and Lantsang, grassland, ecological stress,

摘 要 ：定量化评价人类活动对区域生态系统的压力，对客观认识人文因素干扰区域生态系统的演变程度及效应强度具有重要的意义。在系统总结前人对生态压力指数评价方法的基础上，结合江河源区草地生态系统的现实情况，将生态压力指数定义为草地现实承载力与理论承载力之比，构建了生态压力指数评价模型，并定量分析了江河源区果洛州、海南州、玉树州1961~2002年40a来的生态压力指数。结果表明畜牧业对该区草地生态压力负荷较大；相对于温度和降水等自然因素，以放牧为主的人文因素在短期内对该区草地生态系统演变的作用更加剧烈，从生态压力指数来看，黄河源区下游的海南州的生态压力指数均大于2，已严重超载；同时近40a的生态压力指数的动态变化还揭示了人文因素对区域生态环境演变的影响具有一定的时滞现象，这种时滞现象和人文因素的强度、该区生态系统的承载能力和抗干扰能力具有一定的关系。

Abstract:For many years the ecological stress caused by animal husbandry has been very high in the river resource regions, beyond the realistic carrying capacity of the grasslands, especially in Hainan prefecture. Using an ecological stress index defined as the ratio of realistic carrying capacity and theoretical carrying capacity of grassland, ecological stress indices of the Guoluo, Hainan and Yushu prefecture were calculated from 1961 to 2002. Evolution of the grassland ecosystem over the period was more seriously influenced by human factors than by natural factors such as temperature and precipitation changes. Numbers of sheep in the Hainan prefecture were much higher than the realistic carrying capacity. There appeared to be a time lag before the influence of human factors became apparent in the evolution of a river source region, which was related to the intensity of humanity activities, carrying capacity and the “anti-interference” ability of the grassland ecosystem.

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