基于RS与GIS的北京近30年湿地景观格局变化分析

利用RS图像处理和GIS信息提取和分析功能,确定北京市区域湿地的景观分类系统,获取北京湿地景观数据。同时,基于Fragstats软件,运用景观生态学原理,通过选取景观面积指数、斑块数及斑块密度、斑块聚集度、景观形状指数、斑块分维数和景观多样性指数等空间结构指标,从景观水平上研究了1978—2005年近30年来北京湿地景观分布格局特征的动态变化过程。结果表明:1)北京地区的湿地资源面积呈现显著退化趋势,湿地面积由1978年的68491.63hm2减少到2005年的31416.31hm2,减少了54.0%;2)1978—2005年,北京湿地斑块趋向于不规则化,破碎程度急剧增加,导致湿地易消退、湿地功能难以发挥;3)随着人类干扰强度的增加,北京湿地类型多样性指数值在1.2以上,与均匀度指数呈明显正相关关系,二者均有增加趋势。

Changes of landscape patterns in Beijing wetlands over the past three decades based on RS and GIS technologies

We studied the dynamic changes of landscape patterns in wetlands of Beijing from 1978 to 2005, using remote sensing (RS) and geographic information system (GIS). Based on a Fragstats software, we choose the following indices of landscape patterns, i.e. landscape area index, patch number and density, aggregation index, landscape shape index, fractal dimension and landscape diversity index. The results show that: 1) there has been a significantly decreasing trend of wetland resources in Beijing over the past three decades; the wetland area declined by 54.0%, reducing from 68 491.63 hm2 in 1978 to 31 416.31 hm2 in 2005; 2) The patches of wetland in Beijing tend to be irregular and the degree of fragmentation is increasing, which may result in the degradation of wetlands and the difficulties to exert their functions; 3) Because of the disturbance of human activities, the landscape diversity index has risen above 1.2 and shows a positive correlation with the evenness index, i.e. both increased.