地理学报 ›› 2005, Vol. 60 ›› Issue (6): 965-973.doi: 10.11821/xb200506009

• 土地利用与生态环境 • 上一篇    下一篇

藏北地区草地退化的时空分布特征

高清竹1, 李玉娥1, 林而达1, 江村旺扎2, 万运帆1, 熊伟1, 王宝山2, 李文福2   

  1. 1. 中国农业科学院农业环境与可持续发展研究所,北京 100081;
    2. 西藏自治区那曲地区农牧局,那曲 852100
  • 收稿日期:2005-05-10 修回日期:2005-09-20 出版日期:2005-11-25 发布日期:2005-11-25
  • 通讯作者: 林而达, 研究员。E-mail: lined@ns.ami.ac.cn
  • 作者简介:高清竹 (1975-), 男,博士, 内蒙古科左中旗人。主要研究方向为全球变化与生态安全以及遥感与地理信息系统应用。E-mail: gaoqzh@ns.ami.ac.cn
  • 基金资助:

    国家重点基础研究发展规划项目 (2002CB412508) ;西藏那曲地区与中国农业科学院合作项目"西藏那曲地区草地退化现状及其动态遥感监测"

Temporal and Spatial Distribution of Grassland Degradation in Northern Tibet

GAO Qingzhu1, LI Yu'e1, LIN Erda1, Jiangcun Wangzha2, WAN Yunfan1, XIONG Wei1, WANG Baoshan2, LI Wenfu2   

  1. 1. Institute of Agricultural Environment and Sustainable Development, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
    2. Naqu Bureau of Agriculture and Husbandry Management Department, Tibet Autonomous Region, Naqu 852100, China
  • Received:2005-05-10 Revised:2005-09-20 Online:2005-11-25 Published:2005-11-25
  • Supported by:

    The National Basic Research Program of China, No.2002CB412508;Cooperation Project with Naqu Bureau of Agriculture and Husbandry Management Department and Institute of Agricultural Environment and Sustainable Development "Remote sensing monitoring of grassland degradation of Naqu region in Tibet autonomous region"

摘要:

根据草地退化国家标准和藏北地区草地退化实际情况以及遥感数据特征,选择草地植被盖度为草地退化的遥感监测指标,建立藏北地区草地退化遥感监测和评价指标体系,并对藏北地区近24年的草地退化进行遥感监测和评价。结果表明:藏北地区草地退化现状 (2004年) 十分严重,重度和极重度退化草地面积分别占草地总面积的8.0%和1.7%,区域草地退化指数 (GDI) 为1.86,接近中度退化等级;其中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;从1981年到2004年的近24年以来,藏北地区及其各个区域草地退化较为严重,其草地退化等级分布比例和草地退化指数年际波动较大,草地退化等级在轻度退化至重度退化等级之间波动;近几年藏北全地区总体草地退化情况及中部、东部和北部地区的草地退化具有更加严重的趋势,而西部地区草地退化状况则略有减缓趋势。

关键词: 草地退化, 遥感监测, 时空分布特征, 藏北地区

Abstract:

Ranging from 83o41' to 95o11'E and from 30o27' to 35o39'N, northern Tibet in the highest of Tibet is known as the ridge of the roof of world with a mean elevation of 4500 m. Northern Tibet is the headstream of the Yangtze River, Nujiang River and Lancang River. It is both the "sensitive area" of climate system and the "water tower" of China. The environmental condition of this area has significant effect on the main rivers, climate and eco-environment of Tibet and the whole country, even on the globe for its rigorous natural condition and fragile ecosystem. This study selected vegetation cover as the main evaluation index, calculated the grassland degradation index (GDI) and established the remote sense monitoring and evaluation system for grassland degradation in northern Tibet, according to the national standard (GB19377-2003), based on the remote sensing data such as NDVI data derived from NOAA/AVHRR with a spatial resolution of 8 km of 1981-2000 and from SPOT/VGT with a spatial resolution of 1 km of 2001 and from MODIS with a spatial resolution of 0.25 km of 2002-2004 respectively in this area, in combination with the actual condition of grassland degradation. The grassland degradation processes and their response to climate change during 1981-2004 were discussed and analyzed systematically in the study. The result indicated that grassland degradation in northern Tibet is very severe, and mean value of the GDI in recent 20 years is 2.54 which belongs to the severe degradation grade. From 1981 to 2004, the grassland degradation fluctuated evidently with great interannual variations in proportion of degradation degree and GDI but the total tendency turned to severe during this period with the grassland degradation grade changed from light to severe in northern Tibet. The extremely seriously degraded and seriously degraded respectively occupied 1.7% and 8.0% of the study area, the moderately and lightly degraded grassland accounted for 13.2% and 27.9% respectively and un-degraded grassland occupied 49.2% of the total grassland area in 2004. The grassland degradation was severe especially in the conjunctive area of Naqu, Biru and Jiali counties, the headstream of the Yangtze River that is Galadandong snow mountain, the areas along the Qinghai-Tibet railway and highway, and areas around the Tanggula and Nyainqentanglha snow mountains and glaciers. So the snow mountains and glaciers as well as their adjacent areas in northern Tibet which were sensitive to climate change and the areas along the vital communication line with frequent human activities experienced relatively severe grassland degradation.

Key words: grassland degradation, remote sensing monitoring, temporal and spatial distribution, northern Tibet