金沙江流域云南段景观格局特征及其变化研究

Study on Landscape Pattern Feature and Its Change in Jinsha River Watershed(Yunnan Part)

金沙江流域是我国西部的生态脆弱区,植被受人为干扰程度较大。通过分析区内各植被类型的斑块规模与变化,可望得出人类活动对流域内植被的影响程度。研究基于TM遥感数据进行,首先,对金沙江流域云南段进行景观格局特征研究,分析该地区各植被类型的斑块数、面积,面积标准差和变异系数及该地区的斑块粒度等;然后,对比分析了流域内前后两期(相隔10 a)的植被与景观规模的变化。分析得出,流域内植被类型的斑块多为小斑块和中斑块,体现出植被景观的高度破碎化。经过10 a的变化后,暖温性针叶林等植被面积增加明显,充分反映出人工造林的成效;此外受人为活动影响后形成的次生性植被增多,说明人类活动对植被的不良影响。在植被总体面积增加的同时,区域内景观的斑块总数却有所减少,说明区域内有小斑块融合成大斑块的趋势。从两个时段植被景观斑块规模的变化可以看出,整个流域植被景观破碎的程度体现出减弱的趋势。

Jinsha river watershed is the ecologically fragile area in Chinese western region,and its vegetation was often disturbed by human.Through the study on patch size and change for all kinds of vegetation in this region,the effects from human disturbance can be acquired.Remote Sensing Data（Landsat TM） were used to study landscape patterns in part of Jinsha river watershed,inside Yunnan province,and some patch metrics,such as amounts,areas,standard deviation,coefficient of variance granularity,were calculated.Furthermore, the vegetations and patch size changes between two periods（1996 and 2006）,were analyzed,The results show that middle and small patches dominate in this region,and it reflected that landscape are highly fragmentized in this area.After 10 years,the area of warm temperate coniferous forest,increase vastly,it indicates the result of afforestation.But the area of shrub grassland,a secondary vegetation,which comes into being because of human disturbance,also increased,it means the negative impact caused by human.While the plant area increased,patch amount decrease contrary.And small patches tend to inosculate larger patch.All these changes show that the landscape fragmentation has been weakened to some degree in Jinsha river watershed.