海南岛西部沿海地区20世纪30年代以来土地利用变化及其驱动机制分析

Land Use Changes and Driving Factors in West Coastal Area of Hainan Island Since 1930s

选取海南岛目前风沙影响最严重的地区——昌江县西部的昌化地区和海南西部最干旱的地方——东方市八所地区作为研究区,利用20世纪30年代1∶50000、50年代1∶25000和70年代1∶50000 3个时期的地形图,以及1986年和2000年TM影像图,解译了5期土地利用数据,以此为基础资料,并参考了有关文献,对海南西部沿海地区近80年土地利用的变化特点、趋势及其成因进行了系统的探讨.结果表明:近80年来,水田和建筑用地一直呈增加趋势;荒草地在20世纪50年代之前变化很小,以后持续减少;风沙化土地呈现低—高—低的变化特征,以20世纪50年代最多;林地、旱地表现为由多到少再到多的变化过程,其中林地是20世纪50年代最少,而旱地是20世纪70年代最少;防护林地从无到有到大面积增加.20世纪30—50年代是西部沿海地区风沙危害最严重、生态环境相对较差的时期.自然生态环境的脆弱性是其基础条件,而大规模的人类活动则是其变化的主要原因,人为因素一直通过正反2个方面起决定性的作用.

disaster, The eco-environment of west coastal region in Hainan Island is extremely fragile. Frequent drought and strong wind constitute the basic features of the region. The Changhua district in the west of Changjiang County, together with the Basou district of Dongfang City which is one of the most arid areas in Hainan, is chosen as study area. By the use of topographical maps, including that of 1：50 000 in the 1930s, 1：25 000 in the 1950s, 1：50 000 in the 1970s, and the TM image data in the year of 1986 and 2000, the land use in 5 phases of the region were interpreted. Many other sources of literature were also referred to find the changing characteristics, tendency and causes of land use in the region. The results show： over the past 100 years, the area of paddy fields and construction lands kept increasing; the area of grass lands hardly changed before 1950s, then decreased continuously afterwards ; the change of desertification lands area sees a low-high-low pattern, reaching its peak in the 1950s; the area of forest lands and dry lands both went down to a lowest point （1950s for forest lands and 1970s for dry lands） and then recovered; and, before a certain time, there was no shelter belt forests, yet nowadays there are large amount of lands being put aside for the forests. As a whole, our study demonstrates that, during the 1930s and the 1950s, the desertification in the west coastal region of Hainan was most serious, giving rise to a relatively poor eco-environment. The authors point out that, for the study region, natural condition only provides a background for the fragility of eco-environment, detailed research into land change causes in history clearly shows that human activity always plays a controlling role.