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作 者 ：高清竹,段敏杰,万运帆,李玉娥,郭亚奇,江村旺扎

期 刊 ：生态学报 2010年 30卷 15期 页码：4129~4136

关键词：土壤侵蚀；沙漠化；草地退化；综合评价；地理信息系统；藏北地区；

Keywords:soil erosion, desertification, grassland degradation, comprehensive evaluation, Geographic Information Systems (GIS), Northern Tibet,

摘 要 ：藏北地区自然条件极为严酷，生态与环境非常脆弱和敏感。采用地理信息系统手段与综合评价方法，对藏北地区主要生态与环境敏感性问题进行评估，分析了土壤侵蚀、沙漠化和草地退化等方面的敏感性空间分异规律，指出了今后生态与环境建设的优先区域。结果表明：藏北地区土壤侵蚀敏感区占土地总面积的42.5％，主要分布于东中部区域；藏北地区沙漠化敏感区面积较大（占土地总面积的78.8％），主要分布在人类活动强度相对较低的西北部；藏北中东部和北部地区草地退化较为严重，尤其是藏北地区冰川与雪山及其周围等气候变化较为敏感区域和交通要道沿线等人类活动较为频繁区域的草地退化相对严重，对草地退化也比较敏感，是今后草地退化治理和恢复的优先区。

Abstract:Northern Tibet is the headstream region for the Yangtze, Nu (Salween River), Lancang (Mekong River), and their numerous tributaries and high mountain lakes. It is also a major livestock production centre in Tibet which is one of the nation′s five key livestock raising provinces. However, Northern Tibet is situated in an extremely harsh natural environment and hosts vulnerable ecosystems which are at risk from global climate change. Alpine grassland is not only the most important and largest ecosystem in this area, but also a key resource for supporting local people′s subsistence. In recent years, large areas of alpine grassland ecosystem of Northern Tibet have been severely degraded and threatened by soil erosion and desertification. Sustaining the environmental conditions of alpine grassland ecosystem in Northern Tibet is of vital importance for the Autonomous Region and the whole of China. Due to lack of comprehensive assessments, there is difficulty in identifying the spatial distribution of eco-environmental sensitivity and the priority regions of ecological and environmental construction in Northern Tibet. Therefore, major ecological problems and environmental sensitivities were analyzed and priority areas of ecological and environmental construction identified by assessing the spatial distribution of sensitivity to soil erosion, desertification and grassland degradation in Northern Tibet based on a comprehensive analysis of GIS data The results showed that: the areas sensitive to soil erosion accounted for 42.5% of the total land area and were mainly distributed in the eastern and central regions which comprise the economically relatively more developed and more densely populated areas of Northern Tibet, which seemed to indicate that soil erosion could deeply influence the economic development of Northern Tibet and also of Tibet as a whole. The areas sensitive to desertification, larger than those sensitive to soil erosion, occupied 78.8% of the total land area and were mainly distributed in the northwest of Northern Tibet. Their occurrence increased progressively from southeast to northwest. Degraded grassland accounted for 50.8% of the total grassland area. The degree of grassland degradation in the middle, eastern and northern regions of Northern Tibet was more serious, whereas the grassland degradation in the vast western region was relatively slight. The snow covered mountains and glaciers and the surrounding areas in Northern Tibet were more sensitive to changes is weather patterns, while the areas along the arterial traffic lines were more strongly impacted by human activities. The alpine grassland in these areas was rather severely degraded and susceptible to further degradation in the future. The areas most sensitive to soil erosion, desertification and grassland degradation are considered priority regions for future ecological and environmental construction in Northern Tibet.

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