江汉平原土地利用的时空变化及其驱动因素分析

采用遥感、GIS一体化技术,利用1989～1990、1995～1996和1999～2000年获取的三期陆地资源卫星图像,对江汉平原土地利用10年变化和以1995～1996年为界的前后两个5年变化的时空特征进行了分析,并探讨了变化的驱动因素。结果表明,该区的土地利用在不同的时间及空间尺度上有明显不同的特点。10年间,耕地减少近5万hm²,其中,前5年的减少量占多数,达6783%。各类建设用地总计增加了156万hm²,其中,前5年的增加量是后5年的2倍。水域面积在10年间增加了达到354万hm²,后5年的增幅不到前期的1/2。土地利用变化最快的区域均处于工业经济较发达、城市化较快的地区如武汉、仙桃,变化最慢的区域在监利、松滋、天门等地。政策、社会经济与科技因素对土地利用随时间尺度的变化有决定性的影响。

The spatial-temporal pattern and driving forces of land use change in the Jianghan Plain during 1990-2000

The study on the land use/cover change is one of the frontiers and the hot spots in the global change research. By using the Landsat TM and ETM data which were acquired in 1989～1990,1995～1996 and 1999～2000 respectively, we analyzed the spatial-temporal characteristics of land use/cover changes in the Jianghan Plain at time scales of 10 years and 5 years. The result shows that the spatial-temporal characteristics of land-use change varied with the change of scales during this period of time. During this period of time,the cultivated land area decreased by nearly 5×10⁴ha², of which 67.83% occurred in the previous 5 years between 1989-1990 and 1995-1996. The built-up land and water area expanded with an increase of 1.56×10⁴ha² and 3.54×10⁴ha² respectively, and the expansion at the latter 5 years between 1995-1996 and 1999-2000 was only about 1/2 of the increase amount during the previous 5 years. Large-scale reclamation that was a popular method to get arable land before the 1980s has been limited. There are significant shifts among cultivated land, water bodies and built-up land. From 1990-2000, 76.47% of the lost arable land was converted to water bodies and 22.36% to built-up land. 78.93% of the increased built-up land was gotten at the expense of cultivated land, while 12.93% and 7.04% at the expense of woodland and water bodies respectively. The rate of land-use change in every county and city is different. Wuhan and Xiantao have gotten the greatest value of the dynamic degree of land-use change in all the administrative districts due to the relatively developed industry and economies and fast urbanization, which means that the land-use in these cities changed quickly. The slowest changed areas were Jianli,Songzi and Tianmen. On the whole, the land use changes from 1990-2000 in the study area have been driven by urbanization and industrialization, infrastructure and agricultural intensification. The rapid growth of population and economies play an important role in the land use changes, and the advances in techniques also give rise to the changes obviously. To a great extent, the policy on land use has a definitively influence on the land use changes of different scales. In view of the results mentioned above, some strategies and policies should be reoriented to attenuate the conflicts among the protection of cultivated land and ecosystems and social-economic needs for expansion of built-up land.