黄河源区玛多县土地利用时空格局分析

为了给黄河源区生态环境保护和建设提供科学依据,基于GIS技术,利用3期(1985、1995和2000年)Landsat TM图像解译结果,分阶段分析了玛多县土地利用变化格局特征。结果表明,玛多县土地覆被系统变化具有稳定微动的特征,但其在1985~1995年和1995~2000年两个研究时段的变化特征差异明显,尤其是中、低覆盖草地的变化具有数量巨大且反复多变的特点。1985~1995年,土地利用转移主要发生在疏林地与低覆盖草地、低覆盖草地与未利用地之间以及草地内部的转化,其转移面积占总转移面积的93.03%,其中中覆盖草地-低覆盖草地、草地-未利用土地面积分别占总转移面积的26.14%和18.99%,100%的疏林地向低覆盖草地转移,表明生态环境严重退化;1995~2000年,草地和未利用土地间的转移以及草地内部的转移面积占总转移面积的97.26%,其中未利用土地向低覆盖草地净转移面积及低覆盖草地-中覆盖草地面积分别占总转移面积的18.15%和27.46%,表明生态保护初显成效;从空间格局看,玛多县东部和中部,土地覆被系统变化较明显。

Analyzing on the spatial-temporal pattern of land-use change in Maduo County of the riverhead area of the Yellow River

In order to provide scientific basis for ecological environmental protection and construction in source area of Yellow River,supported by the technique of GIS,the spatial-temporal pattern characters of LUCC in Maduo County from 1985 to 2000 were analyzed based on Landsat TM digital data.Some significant findings were obtained.Though LUCC in Maduo County kept steady with slight change,the changing characters in the two research period of time(1985-1995 and 1995-2000) were obviously different,and especially,the converting of mid-coverage pasture and low-coverage pasture showed the characters of huge numbers and rotation.During the period of 1985-1995,the land-use transforming mainly occurred between thin woodland and low-cover grassland,low-cover grassland and non-used land,as well as within the range of grassland,accounting generally for 93.03% of the total transformed amount;conversion amount from mid-cover grassland to low-cover grassland and from grassland to non-used land accounts respectively for 26.14% and 18.99% of the total conversion amounts;all the thin woodland had been converted into low-cover grassland.The conversion characters mentioned above showed that the environment in Maduo County from 1985 to 1995 degraded badly.During the period of 1995-2000,the conversion amount between grassland and non-used land accounted generally for 97.26% of the total conversion amount.The net change from non-used land to low overlay degree grassland and from low-cover degree grassland to mid-cover grassland accounts respectively for 18.15% and 27.46% of the total conversion amounts.The above characters show that environmental protection in Maduo County has succeeded originally.During the two periods of 1985-1995 and 1995-2000,land-use conversion obviously occurred in the eastern and middle districts of Maduo County.