近15年来杭州西溪湿地景观格局变化研究

Studies on the Changes of Landscape Patterns of Hangzhou Xixi Wetland in 15 years

在遥感和地理信息系统支持下,利用1991年、1999年和2004年三个时期的Landsat-TM5、4、3波段合成影像作为信息源,选取斑块面积、斑块数、斑块分维数、斑块破碎化指数、最大斑块指数、多样性、均匀度等指标,对杭州西溪湿地景观格局变化进行了定量分析。结果表明,1991-2004年近15年间,由于杭州城市扩张及房地产开发等人为因素,池塘和河流等1991年最占优势的景观类型,到2004年已变成了建设用地和农用地,景观格局发生了显著的变化;建设用地和农用地对整个湿地的控制作用不断增强,导致景观多样性指数降低、能物流不畅、生物多样性下降,环境污染趋重,湿地生态功能退化。因此,今后在西溪湿地开发中应十分注重保护和部分恢复池塘和河流等景观类型,以实现可持续利用。

Landsat TM imagery （band5, band4 and band3）, in years 1991, 1999 and 2004 were used to study the changes of landscape patterns of Hangzhou Xixi wetland with the support of GIS. Indicators selected in the study included patch areas, number of patches, fractal dimension, fragmentation index, largest patch index, diversity and evenness index, etc. Results showed that the changes of landscape patterns were significant from 1991 to 2004 because of urban expansion and real estate development. The dominant landscape types of rivers and ponds in 1991 have been replaced by constructed land and farmland in 2004, which became control factors over the whole wetland and resulted in decreased landscape diversity index, material and energy flow, and biodiversity, environmental pollution, and deterioration of ecological functions of the wetland. It is suggest that conserving and partially restoring ponds and rivers should be greatly emphasized in future development of the Xixi wetland for its sustainable utilization.