疏勒河上游山区不同海拔梯度的景观格局变化  

Landscape pattern change in mountainous areas along an altitude gradient in the upper reaches of Shule River

作　　者：谢霞[1] 杨国靖[1] 王增如[1] 王杰[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所寒旱区水文与水土资源实验室,兰州730000

出　　处：《生态学杂志》2010年第7期1420-1426,共7页Chinese Journal of Ecology

基　　金：中国科学院知识创新工程重要方向项目(KZCX2-YW-QN310);国家重点基础研究发展计划资助项目(2007CB411502)

摘　　要：基于1986年7月的LandsatTM和2001年7月的LandsatE TM遥感影像及1:50000DEM数据,利用ArcViewGIS3.3和Fragstats3.3软件对祁连山西端疏勒河上游山区不同海拔高程带的景观变化进行了分析。结果表明:整体景观上,疏勒河上游山区以草地为基质,灌丛与其他景观类型作为斑块镶嵌其中,结构组成单一,形状规则,斑块分布集中;在景观要素水平上,低覆盖度草地所占面积最大,其次是裸岩石砾地,所有植被约占52%,高覆盖度草地仅占5%,居民点少且分散;15年里,草地退化严重,灌丛、高覆盖度草地、低覆盖度草地和沼泽地面积减少,裸地、河滩地、中覆盖度草地和农田面积增加;草地在3800～4000m的海拔高程带内退化最为严重,而这一高程带正是该区多年冻土分布的下限,因气候变暖而导致的冻土活动层增厚与土壤含水量的降低是草地退化的主要原因。Based on the Landsat TM images in July 1986,Landsat ETM images in July 2001,and 1：50000 DEM data,the landscape pattern change in the mountainous areas along an altitude gradient in the upper reaches of Shule River from 1986 to 2001 was studied by using software ArcView GIS 3.3 and Fragstats 3.3.In the study areas,grassland was the matrix,while shrubs and other landscape types were the mosaic patches.The landscape had simple structure,single composition,regular shape,centralized patch distribution,and a few dispersed residential points.Among the landscape types,sparse grassland had the largest area,followed by naked gravel land.The vegetation coverage was about 52%,and dense grassland only accounted for 5%.In the 15 years,the areas of shrubs,dense grassland,sparse grassland,and swamp meadow decreased due to degradation,while those of mid-density grassland,barren land,bottom land,and cropland increased.The grassland at the altitude 3800-4000 m,the lower limit of permafrost distribution,was undergone most serious degradation.The thickening of active permafrost layer and the decrease of soil moisture content due to climate warming could be the main reasons of grassland degradation.

关 键 词：景观变化 草地 高程带 山区 冻土 

分 类 号：Q149[生物学—生态学]