地形因子对三江平原土地利用/覆被变化的影响研究

在遥感和地理信息系统技术支持下,分析了1954—2005年海拔高度和坡度因素对三江平原土地利用/覆被变化过程的影响。结果表明,过去近50 a,三江平原土地利用/覆被变化剧烈,其中耕地增加了2.25倍。与耕地面积急剧增加相对应的是湿地、林地和草地的大幅度减少。各土地利用类型的动态变化在不同海拔高度的地表区域有不同的表现,其中耕地的增加主要发生在海拔200 m以下的地貌部位,尤其是海拔100 m以下的地貌部位;湿地面积的减少也主要发生在海拔200 m以下的地貌部位,其中大部分发生在海拔100 m以下的地表单元。林地与草地在各个海拔高度区间的变化趋势呈波动状态。城乡工矿用地在各个海拔高度区间都有一定的变化,其中海拔200 m以下变化尤为明显。三江平原耕地面积在各个坡度级别上均呈增长趋势,在坡度小于1°的地貌部位增加最多。坡度大于10°时,耕地面积的增长比例非常小。林地、草地和湿地的变化均主要发生在坡度小于1°的地貌部位。水域、城乡工矿用地的变化主要发生在坡度较小的地貌部位。

Impacts of Topographic Features on Landuse/Cover Change in Sanjiang Plain

Based on remote sensing and geographic information system technologies,the effects of altitude and slope factors on the process of land use/cover changes in Sanjiang Plain during 1954-2005 were studied.Results showed that during the past five decades,landuse in Sanjiang Plain changed substantially and cropland increased by 2.25 times.In contrast,wetland,woodland,and grassland decreased considerably.Changes of land use types have different features in altitude classes.Cropland increased mainly at the locations below 200 m,especially at locations below 100 m.Wetland decreased mainly in the same way as cropland in terms of altitude.Woodland and grassland showed a fluctuant changing trend in all altitude classes during different periods.Built-up land changed in all altitude classes,but mainly happened below 200 m.For slope degree,cropland increased at all slope classes and increased mainly at locations below 1°.The area of cropland had a relatively small increase at locations above 10°.Changes of woodland,grassland,and wetland mainly happened on 1° slope degree class.Water body and built-up land also changed mainly at sites with small slope gradients.