黄河源区土地利用和景观格局变化及其生态环境效应

基于TM/ETM卫星遥感数据,运用ArcInfo软件和景观生态学方法,对黄河源区1986～2000年土地利用和景观结构的时空变化特征进行了研究。结果表明:源区林地、湿地、草地和冰川面积减少,建设用地、耕地和未利用土地面积显著增加,土地综合利用程度下降。景观破碎化程度加剧,分维数和多样性指数增加,优势度提高,景观异质性增强。黄河源区脆弱的生态体系对土地利用变化响应强烈,造成水土流失与沙漠化程度加剧,导致大范围高寒草甸、草原植被退化,湿地萎缩。区域气候变化及其引起的冻土环境退化,以及所叠加的不合理的人类经济活动和较为严重的鼠虫害是黄河源区生态环境急剧恶化的主要成因。

Land Use Change and Its Impact in the Eco-environment on the Yellow River Source Region Dring the Past 15 Years

Based on 1986 TM and 2000 ETM datum,the land use and landscape pattern change of the Yellow River source region were studied in macro-scale by ArcInfo and landscape ecology methods. The results showed that significant changes have taken place in the past 15 years. Construction land,unused land and cultivated land area increased rapidly. Grassland reduced and increasingly changed into unused land. Wetland and the forest land decreased obviously, and the comprehensive land use index reduced by 0.11. The landscape fragmentation degree,the fractal dimension and the diversity index increased,which imply the enhancement of landscape heterogeneity. The eco-environment in the study area was very vulnerable and sensitive to the land use change,which resulted in land desertification\, soil and water loss,and degradation of high-cold meadow vegetation and wetland. Abnormal climate was the inducing and key factor,and irrational human being activities and rat damage were aggravating factors lead to these changes.