内陆干旱区土地利用变化的景观格局特征分析——以新疆白杨河流域为例

基于GIS/RS环境对两期Landsat7-ETM 影像数据进行土地利用分类处理,运用景观生态学原理和数理统计分析方法,从区域整体景观格局水平和土地利用类型水平两个角度,选取景观多样性指数等5个指数描述白杨河流域土地利用变化的景观格局特征。结果表明:研究区各土地利用类型面积都有不同程度的变化,除草地和未利用土地有所减少,其他土地利用类型都有不同程度的增加。从景观水平上看,区域景观异质性在增大,景观斑块的连通性降低,表现为多样性指数和均匀度指数呈增加,优势度指数减小;从类型水平上看,5年间人类对景观的干预程度较大,对人工景观的干扰强于半自然景观,体现在半自然景观类型的分离度较小,而人工景观类型的分离度较大。同时,景观周长-面积分维度指数的增长趋势说明景观斑块的自我相似性减小,几何形状趋于复杂化。总体上,是人类活动加剧破坏了自然绿洲内部的整体性和完整性,并且人类活动干扰还在增加。

Characteristics of landscape patterns of land use change in arid areas:A case study of oasis at the Baiyang River Watershed in Xinjiang

Based on the technique of Geographical Information System(GIS) and Remote Sensing(RS),the information of land use change from two periods of Landsat7-ETM images in 2000 and 2005 is derived.Using the methods of landscape ecology and statistical analysis,the paper selected five indices based on landscape level and class level to describe the characteristics of landscape patterns of the oasis at the Baiyang River Watershed,Fukang County,Xijiang,China.The results show that the amount of each land use type is changed with different degrees.The amount of many land use types is increased while that of meadow and unused land decreased.On the landscape level,the regional landscape heterogeneity is increased and the connectivity reduced,which presents the increase of Shannon's diversity index and Evenness Index,decrease of dominance index and increase of fragmentation index.On the class level,it shows that human disturbance on landscape is intense during the past five years,and the disturbance to artificial landscape is more intense than that on semi-natural landscape,which means that the fragmentation index of semi-natural landscape is relatively smaller while that of the artificial landscape is larger.Meanwhile,the increasing trend of the landscape perimeter-area sub-dimensions index(PAFRAC) indicates that the self-similarity of landscape patch is decreased,and the geometric shape tends to complication.As a whole,it is the intense human activities that destruct the wholeness and integrality of the natural oasis,and what's more,the disturbance of human activities is still aggravating.