1954年以来三江平原土地利用变化及驱动力

Land Use Change in Sanjiang Plain and Its Driving Forces Analysis since 1954

在遥感和地理信息系统技术支持下,获取了自1954年以来三江平原6期土地利用数据,在GIS空间分析模块下对三江平原土地利用方式及格局的动态变化进行了定量研究。结果表明在过去50年里,三江平原的土地利用方式发生了显著变化。耕地净增加了38.55×105hm2,年均增加75597.3hm2,其中湿地、林地与草地对耕地的增加贡献最大;湿地减少了25.67×105hm2,除极少数退化为草地外,绝大部分转化为耕地;草地减少了57.65×104hm2hm2,面积比由9.13%缩减为3.86%;林地在整个研究期间呈现出一定波动趋势,但总体呈减少趋势;水域与未利用地也呈现出减少趋势;居工地则呈现快速增长趋势,而且其年增长率为6.96%,远远大于其他土地利用的年增长率。耕地变化是驱动三江平原其他土地利用变化的直接因素,通过对人口与国家农业经济政策分析表明,耕地变化与人口增加关系密切,回归确定性系数为0.93,同样国家宏观农业政策与市场对土地利用格局变化起着不可忽视的作用,近年来水田面积的快速增加就是其直接作用的结果。

This study aims at revealing how land use and land cover change in the Sanjiang Plain since 1954. Based on the remote sensing imagery data and topographic map, a six-stage spatial data base was established with ArcGIS software. Demographic data, agricultural economic data and other auxiliary data were collected from national and provincial frams statistical bureaus on land reclamation and cultivation, and some relevant documents and various statistical reports were also collected at the perfection of the typical counties since 1954. With GIS spatial analysis tools, the land use and cover change characteristics and the changing trend in the Sanjiang Plain since 1954 are traced and analyzed in this paper. The result indicated that land use changed prominently in the Sanjiang Plain during the past five decades, farmland increased 38.55-10^5 hm^2, averaging an increase of 75597.3 hm^2 per year, and most of them were converted from wetlands, forest and grassland. Wetland decreased dramatically and reduced 25.67×10^5 hm^2 in the 50 years, except a small part being converted into grassland due to the perfection of the drainage syatem for farming, hence most of the wetland was converted into farmland; grassland reduced 57.65×10^4 hm^2, a decrease from 9.13% to 3.86% in the study area; forest also showed a declined changing trend, unused land and water body also kept reducing throughout the period. Residential land use increased dramatically in the corresponding period, and its annual increasing rate occupied 6.96%, much higher than other land use changing rate. Farmland increase is a direct force driving the present land use changing trend, and this change then caused other land use changes in the study area. Correlation analysis between demographic data and farmland area indicated that population increase is the main driving force for farmland increase in the Sanjiang Plain, but the state macroscopic agricultural policies play an important role in the structural changes of land use pattern of the region.