古浪县绿洲边缘植被恢复过程中的土地利用变化特征

以1987、1999和2003年的3期TM影像为基本信息源,通过遥感图像分类解译对古浪县绿洲边缘土地利用转化状况进行马尔柯夫转移矩阵分析．结果显示,1987～2003年全区流动沙地、半流动沙地和半固定沙地的面积共减少了9．60×103hm2,沙漠化呈现明显的逆转趋势,以封育为主的植被恢复取得了明显成效;此外,通过对1987～1999年和 1999-2003年两个阶段的土地利用转化对比分析,沙区植被恢复的“后郊性”特点表现明显,植被恢复效果随植被恢复演替逐步显现;1987～1999年半流动和半固定沙地向固定沙地的转化率分别为15．67％和13．86％,而1999-2003年提高到了21．34％和20．13％．整体上土地利用动态表明,虽然该地植被恢复已取得了一定成效,但生态环境依然十分脆弱,土地退化极易发生,土地荒漠化的威胁仍然存在．

Land use change during vegetation restoration in the edge of Gulang oasis

By interpreting 1987,1999 and 2003 TM image,the land-use change in the marginal zone of the Gulang oasis was analyzed using Markov transfer matrix. The results showed that from 1987 to 2003, the areas of shifting,semi-shifting and semi-fixed sandy land decreased by 9. 60×103 hm2, the desertification tookon an obvious reversing tendency and the vegetation restoration had acquired an evident successful effect. Based on the comparison of land use change, the co-efficiency of vegetation restoration took on an gradual increasing. From 1987 to 1999, the rates of transforming from semi-shifting and semi-fixed sandy land to fixed sandy land were 15.67 % and 13.86 % ,however, it increased to 21.34 % and 20.13 % from 1999 to 2003. Although the whole dynamic variation of land use showed that the vegetation restoration in this area had gained an evident effect,the ecological environment was still very fragile. The threaten of land degradation and desertification were still exist.