基于遥感的渭河关中地区生态景观格局变化研究

Ecological Landscape Patterns in Guanzhong Part of the Weihe River Basin Based on Remote Sensing

基于遥感(RS)和地理信息系统(GIS)技术,以1978年-2007年的Landsat MSS/TM/ETM影像为数据源,综合运用数理统计和景观生态学理论和方法,对渭河流域关中地区1978年-2007年生态景观格局动态变化进行了研究。结果表明:渭河流域关中地区各景观类型都发生了不同程度的消长变化,耕地斑块面积减少,但分离度和破碎度增加;草地和林地斑块面积增加,破碎度和分离度减小;居民工矿建设用地面积显著增加;未利用土地斑块面积有所减少。从景观格局变化来看,渭河流域关中地区景观斑块分布趋于破碎化,破碎度指数从0.9127下降为0.8755;景观多样性指数和景观均匀度指数均在20世纪90年代有所增加,分别增长了2.72%和2.71%,之后锐减,2000年达到最低后逐渐有所回升;景观优势度也在20世纪90年代有所增加,后逐渐减小。说明近期研究区生态景观的异质性有所改进,生态景观格局处于快速调整并趋于稳定发展阶段。

Analysis of changes in ecological landscape patterns is one of key issues in landscape ecology. Studying the dynamic changes in landscape patterns can reveal the interactions between landscape patterns and ecosystems, providing important reference for utilizing natural resources. Remote sensing techniques can be useful in examining ecological landscape patterns, especially in the study of distribution characteristics, evolution rules, spatial relationships of landscape phenomena, and in simulation of ecological landscape patterns. The Weihe River is the largest tributary of the Yellow River. In recent years, land use and ecological landscape changes in the Weihe River basin have received much attention. The Guanzhong part of the Weihe River basin was investigated in this study. Landsat Multispectral Scanner System （MSS）, Thematic Mapper （TM）, and Enhanced Thematic Mapper Plus （ETM＋） imageries covering the Guanzhong part of Weihe river basin acquired in vegetation/crop growing season in the early 1980s, early 1990s, 2000, 2005 and 2007 were obtained. Landscape ecology theory was used to examine the dynamic changes in landscape patterns across the study area from 1978 to 2007. First, satellite images were geometrically and atmospherically processed. Training classes/sites of ecological landscape types for imagery interpretation by visual interpretation were determined. Thematic maps of ecological landscape types were made. Then, topological analysis was performed. Finally, ecological landscape indices were calculated and compared to examine the characteristics of changes in ecological landscape patterns. It was concluded that all types of landscapes over the area of interest changed to some extent. The area of farmland decreased, but its fragmentation and separation increased. Grassland and woodland areas increased, but their fragmentation and separation decreased. The area of construction land increased significantly. Unused land area decreased. The landscape over the study area became increasingly dispersed, demonstrated by its fragmentation index decreasing from 0.9127 to 0.8755. The landscape diversity index and evenness index increased by 2.72% and 2.71% in the 1990s, respectively. Landscape dominance also increased in the 1990s, and then gradually decreased. These results indicate improvements in ecological landscape heterogeneity. Ecological landscape patterns changed rapidly, but showed a gradually stabilized trend.