基于RS和GIS的包头市土地利用动态及其生态效应定量研究

在RS，GIS和多种模型支持下，对包头市1987～2002年土地利用动态及生态效应进行了研究。结果表明：（1）包头市1987～2002年林地、草地和水域有不同程度减少。而建设用地、未利用土地和耕地有不同程度的增加。土地利用类型变动的总体方向是：林地、草地和水域主要转向耕地。发生利用类型转移的草地中，31．5％转为未利用土地；新增耕地主要来自草地和未利用土地。二者分别占非耕地转为耕地总量的36．34％和27．6l％。新增建设用地主要来自草地和耕地。二者分别占非建设用地转为建设用地总量的49．86％和34．28％。（2）包头市1987～2002年区域综合生态环境质量下降。土地退化特别是草地退化和拓展耕地是区域生态环境恶化的主要原因，其生态贡献率分别是51．84％（41．04％），23．63％。（3）土地利用动态及其生态效应存在空间差异，16年间各区、县、旗的综合生态环境质量均下降，但以达茂为最，土右最慢。前者草地退化起决定作用。其生态贡献率达96．61％；而后者草地退化、植树造林和退耕还林还革的生态贡献率分别是44．23％，18．21％和10．36％，植树造林和退耕还林还草对区域生态环境的改善发挥了一定作用。

Analysis on Land Use Change and Its Eco-Environmental Effects in Baotou City Based on RS and GIS

Based on RS and GIS,land use changes and its driving factors in Baotou from1987 to 2002 have been analysed.The findings can be explained as following:(1) From 1987 to 2002,the areas of forestlands,grasslands and waters are reduced,whereas the areas of other land use types are enlarged.Parts of forestlands,grasslands and waters had becomed farmlands and about 31.5% of the changed grasslands transferred to unused lands.The newly-increased farmlands mainly came from grasslands and unused lands,and the former account for 36.34% while the latter 27.61%.The newly-increased lands for construction mainly came from grasslands and farmlands,and the propotion of them are 49.86% and 34.28% respectively.(2)The general quality of regional eco-environment has deteriorated from 1987 to 2002,and the land degradation,specially the lawn degeneration,and the developing the cultivated land are the main factors which the region ecological environment worsens,the ecological contribution ratio of them respectively is 51.84%(41.04%),23.63%.(3)The tendency of land use changes and its eco-environmental effects displayed spatial heterogeneity.The general quality of regional eco-environment in every district has deteriorated during the last 16 years,and the fastest is Damao County,and the slowest is Tuyou County.The degradation of meadow plays a decisive role in the deterioration of Damao's general ecological environment,and its ecological contribution rate is up to 96.61%.However,the ecological contribution ratio of the meadow degradationg,afforestation and conceding the cultivated land to forest and grass in Tuyou County are 44.23%,18.21% and 10.36% respectively.This indicates that afforestation and conceding the cultivated land to forest and grass play a certain role in the improvement of Tuyou's general ecological environment.