黑河流域土地利用与覆被变化特征

在土地类型划分的基础上, 利用黑河流域1987年和2000年两期TM遥感数据, 从土地利用与覆被变化幅度、变化速率及动态度等角度, 定量分析了流域上、中、下游及全流域总体土地利用与覆被变化的特征并进行了对比.结果表明: 在变化幅度上, 全流域各类土地利用与覆被变化均十分强烈, 中游地区最为显著, 综合土地利用与覆被变化指数达到7.6%, 耕地、城镇建设用地、水域和草地等是全流域变化最为剧烈的利用类型; 在变化速度方面, 流域上游地区的耕地、城镇居民用地和沙漠化土地年平均递增速度最高, 中游地区明显小于上游和下游地区, 但沙漠化除外, 为全流域水平的4.7倍, 下游耕地、城镇用地、水域面积和其它难利用土地变化较快, 说明上、下游生态系统极不稳定, 变化剧烈. 对中游动态度的分析表明, 耕地、城镇居民用地和较难利用土地较稳定, 其它土地类型的利用与覆被动态变化都很活跃, 说明中游地区土地利用与覆被变化复杂而强烈, 具有变化的多向性和互动性, 从而为流域合理调整土地利用方式和环境改善提供了一定的科学依据.

Changing Characteristics of Land-Use and Land-Cover in the Heihe River Basin, China during 1987-2000

Land-use and land-cover change is one of the important issues in global change research because it is not only the significant component but also the major reason of global change. Based on a certain division of land-use and the TM data of the Heihe River basin from 1987 to 2000, and from the changing amplitude, changing rate and spatial dynamic degree of land-use and land-cover, in this paper, the changing characteristics of land-use and land-cover in the Heihe River basin are analyzed, and a contrast among the upper reaches, the middle reaches and the lower reaches is made. In this course, nine quantity indexes that aim at a single land-use type, area land-use type and area integrated land-use type, respectively, are used. From the study, the following conclusions are drawn: (1) The land-use and land-cover change are very serious in the whole river basin, especially in the middle reaches. The plantation, building land, water area and grassplot change most markedly. (2) The plantation, building land and desert land in the upper reaches are changing most rapidly. The plantation, building land, water area and other lands that are difficult to be used are also changing very quick. However, in the middle reaches lands change relatively slowly. (3) Plantation, building land and those lands difficult to be used are relatively stationary, but other lands change quite actively. So, the land-use and land-cover change is very complicated in the middle reaches of the Heihe River.