基于土地利用变化的近18 a新疆沙地动态及其驱动力分析

 基于新疆1990—2008年的土地利用变化数据库利用土地利用转移矩阵和土地利用变化状态与趋势指数模型分析新疆沙地的动态,依据沙地的转化方向及转化源探讨新疆沙地变化的驱动力。研究区沙地在1990—2000年呈增加趋势,增加速率为84.40 km2·a-1,草地转换为沙地的面积最大；2000—2008年呈减少趋势, 2000—2005年和2005—2008年减少速率分别为86.98 km2·a-1和118.26 km2·a-1,且主要转换为耕地。沙地面积的增加和减少受气候干湿变化和人类活动控制。同20世纪50—90年代相比,1990—2000年新疆沙地扩张速率降低了近一半,局部荒漠地区生态环境有所改善,原因为大规模的土地开垦与气候的暖湿变化。2000—2008年新疆沙地面积不断减少,原因为土地开垦模式发生着变化、生态建设的较快发展以及气候处于相对暖湿的状态。但一些地区沙化问题仍然存在,新疆干旱脆弱的生态环境本质没有根本改变,依然存在着土地沙漠化的潜在危机。

Analysis on Sandy Land Dynamics and Driving Forces in the Last 18 Years in Xinjiang Based on Land Use Change Data

Based on Xinjiang land use dynamic data from 1990 to 2008,sandy land dynamics was analyzed with land use transition matrix and index model of land use change status and trend;the driving forces of sandy land dynamics was explored according to sandy land transitional direction and transition source.During 1990—2000,the sandy land area increased with a rate of 84.40 km2·a-1,and grassland was the biggest contributor to sandy land increase.During 2000—2005 and 2005—2008,it decreased with rates of 86.98 km2·a-1 and 118.26 km2·a-1,respectively,and cultivated land was the biggest contributor to sandy land decrease.Desertification was affected by both climate change and human activities.The expanding rate of sandy land during 1990—2000 had decreased by nearly one half of that in 1950—1990,showing the eco-environment of some area improved.The sandy land area in Xinjiang decreased gradually from 2000 to 2008 due to land reclamation,ecological construction and warm and humid climate conditions.The eco-environmental nature being vulnerability and aridity has not yet changed in Xinjiang,so Xinjiang is still endangered by potential desertification crisis.