近期藏北地区草地景观结构及其变化特征分析

Landscape Structure and Changes of Grassland in Northern Tibet in the Recent Ten Years

根据1990年和2000年的两期Landsat-TM数据,应用景观类型斑块等级结构和景观空间格局指数等景观生态学指标,选择藏北地区为研究区,进行景观结构及其变化研究。结果表明:1)高寒草原与高寒草甸是该地区主体景观类型;2)高寒荒漠大幅度扩展,高寒草甸、高寒草原和冰川与雪山等景观类型的减少,使区域生态环境趋于恶化;同时也增大了水域分布面积,一定程度上缓解了生态环境的恶化,但也引起了洪涝灾害,减少了草地面积;3)景观破碎化明显增强,景观异质性在不断降低。

Based on the interpretation of the Landsat-TM data which was with 82 digital images taken in 1990 and 2000 respectively, the landscape structure and its changes of the grassland in the Northern Tibet were studied to reveal the land use change by analyzing the indices of patchsize, spatial pattern and other parameters commonly used in landscape ecology. The preliminary results were as follows： 1 ） Alpine grasslands were the main landscape types in the Northern Tibet. 2） From 1990 to 2000, the alpine desert expanded greatly, while the areas of the landscape types, such as alpine meadow, the alpine grassland, glaciers and snow mountains decreased, which deteriorated the regional eeo-environment. The expanding of the water area lessoned the deterioration of eeo-environment to a certain extent, but also brought the flooding disaster in some regions and reduced the grassland area. 3 ） The landscape pattern there had an obvious trend of fragmentation due to the ever-increasing human activities.