西藏高原草地退化及其成因分析

为恢复与重建西藏退化的草地，维持草原生态系统平衡，在系统阐述西藏高原草地退化现状、退化特征的基础上，就导致草原生态系统退化的自然与人为因素进行深入分析。结果表明：地质、地貌不稳定，土层浅薄，土壤颗粒粗化、石砾化，土壤固结力差，抗冲蚀力弱，是草地退化的物质基础；全球变暖，降水量低且蒸发强烈，大风频繁、强劲且持续时间长，冻融侵蚀强烈是草地退化的动力条件；超载过牧、过度樵采等人为干预的不断增强是草地退化发生、发展的关键。

Grassland degradation and its formation causes analysis in Tibetan plateau

For the soil restoration of degraded grassland in Tibet and maintenance of the grassland ecosystem balance, it is necessary to study on grassland degradation and its causes. This paper systematically describes the present state and characteristics of grassland degradation in Tibet plateau, making an in-depth analysis of the natural and man-made causes leading to the degradation. The results show that the material basis is unstable geomorphology, shallow soil, coarse particles of soil, gravel, poor soil consolidation, erodible soil. Global warming, low precipitation and strong evaporation, frequent strong winds, erosion of freezing and thawing are the dynamic stimulation. The key factors leading to grassland degradation are continuously overloading grazing and other man-made excessive interventions.