内陆河小流域综合治理对景观格局的影响——以童子坝河流域为例

以1987年、2000年、2008年3期LandsatTM影像为信息源,在GIS技术和景观分析软件Fragstats3.3支持下,获得了民乐县童子坝河流域研究区不同时期的景观类型信息和描述景观格局特征的8个景观指数数据,利用这些数据分析了实施综合治理前后流域景观格局的变化。结果表明:①在类型水平上,各种草地景观类型的斑块呈现边缘整齐、形状规则的特点,斑块的破碎化程度减小,聚合度增加;特别是高覆盖度草地的斑块数目、平均斑块面积都呈增加趋势,斑块边界形状变得连续、规则,显现出人为干扰的痕迹;河床、河漫滩景观的斑块数目减少,斑块边界形状趋于规整,贯穿连通性增强。②在景观水平上,景观空间格局规整有序,景观多样性提高,异质性增加,破碎化程度减小,空间连接性增强,以高覆盖度草地为主的景观优势显著体现出来。③综合治理措施实施对童子坝河流域景观格局的影响是积极有效的,这可为内陆河小流域继续开展生态环境建设提供科学依据。

Effect of Comprehensive Management of Small Watershed on Landscape Pattern: A case study of Tongziba River watershed

Based on information sources of Landsat TM images in 1987, 2000, and 2008, the state and change of landscape patterns in Minle County of Gasu Province was derived in assisting of GIS technology and software Fragstats3.3. Eight landscape indices and their dynamic changes were obtained to analyze the effect of comprehensive management of Tongziba River watershed on landscape pattern. The results showed that there was a significant change of landscape patterns after the implementation of small watershed comprehensive management. (1) For grassland patches, the edges appeared more neat and the shape appeared more regular, while the fragmentation degree decreased and the polymerization degree increased after the watershed comprehensive management. The trend was more obvious for the high coverage grassland, revealing the interference of human. The number of river bed and floodplain patches reduced, and the patch shape tended to be more regular and the patch connectivity tended to be more significant. (2) The landscape pattern became more neat and orderly and the diversity and heterogeneity of landscape increased, while landscape fragmentation degree reduced and landscape connectivity enhanced after the watershed comprehensive management. The effect was more significantly demonstrated for the landscape dominated by high coverage grassland. (3) The ecological environment in Tongziba River watershed improved obviously after comprehensive management. The project of watershed comprehensive management had positive effect on the landscape pattern.