洮儿河流域中上游土地利用变化特征分析

Land Use Change in the Middle and Upper Reaches of Taoer River Catchments

该文基于3期TM数据,在GIS支持下,运用景观生态学和统计分析方法,研究了洮儿河流域中上游15年土地利用时空变化特征。研究结果如下: ①时间演变特征:从土地利用演变速率看,草地面积呈显著减少趋势。在1985年～1996年期间减少速率为1 52%,1985年～2000年期间减少速率为1 20%,而难利用地面积减少幅度和速率较小。除了草地和难利用地减少其它类型都呈增加变化。其中耕地增加明显,在1985年～1996年期间增长速率为1 79%,1985年～2000年期间增加速率达到1 40%,而林地在15年内以每年0 82%的速度持续增加; ②空间演变特征:从土地类型结构看草地一直占绝对优势地位,3个时期所占比例分别为46%、46%、38%,但草地无论是面积或质量都呈下降趋势,表现在:高覆盖度草地面积大幅度减少,中覆盖度草地面积增加,斑块数量也由1985年的5498块增加至2000年的5582块,这说明草地在面积减少和质量下降的过程中还表现出明显的破碎化;耕地面积比例呈增加趋势,尤其水田增加幅度大,且集中连片位于水源较好的区域;林地和居工用地的比例也都呈上升趋势;而难利用地比例则大幅度减少。该文还分析了不同土地利用类型在土地利用演化过程中的贡献,结果表明,草地对耕地增长的贡献率最大,其次是难利用地。通过分析看出,研究区土地利用在近15年?

Based on GIS technology and by using three periods of Landsat TM in 1985, 1996 and 2000, this paper analyses the temporal and spatial character of land use/cover change (LUCC) in the middle and upper reaches of Taoerhe river catchments. The results indicate as follows: 1)temporal change: in respect of change speed of LUCC in studying area, grassland area is decreasing notably, from 1985～1996 and 1985～2000, the change rate is 1.52% and 1.52%, respectively. But badland decreasing rate is gentle. Others are increasing in different change rate. Farmlands increase markedly in a rate of 1.79% and 1.40% from 1985～1996 and 1985～2000, respectively; and forests land increase in a rate of 0.82% during 15 years; 2)spatial change: from all kinds of land proportion, grasslands are predominance all through 15 years, and the proportion of grassland is 46% in 1985, 46% in 1996, and 38% in 2000, respectively. But both quality and quantity of grasslands have decreased. For example, good covering grasslands area decrease notably, but bad covering grasslands increase markedly. Further, the number of grasslands patches increase markedly. This means grassland appearing fragments. The proportion of farmlands increase, especially the paddy fields whose proportion increases nearly 3 folds mainly distribute near the sufficient water resources area. The proportion of forestlands, resident or build-up lands increase continuously during 15 years. But the badlands proportion falls. Further, this paper analyzes the land change redounds during all kinds of land changes. The results show that the most redounds are grasslands,then are badlands. Finally, author gives a conclusion that, land changes are fast during the past 15 years, the predominant grasslands change distinctly, and most are intramural adjustment, others are only regulation, this means land use in research area is relatively stable.