托木尔峰国家级自然保护区土地利用/覆被变化及驱动力分析

Analysis of land use/cover change and its driving force in Tomur National Nature Reserve

利用保护区的3期Landsat TM遥感影像数据,运用GIS技术并结合区域生态环境质量指数,对托木尔峰自然保护区土地利用/覆被变化及其驱动力进行分析。结果表明:近27 a来,冰川和草地面积持续增长,增幅分别为12.37%和99.36%;水体和荒地面积持续减少,减幅为23.07%和12.15%;林地前阶段(1989-2003年)减少16.77%,后阶段(2003-2016年)增加57.91%。区域土地利用/覆被综合动态度,前阶段为0.39%,后阶段为0.36%;前阶段转化率为21.95%,后阶段转化率为18.91%。水体、草地和林地的转化率较高,冰川和荒地的转化率较低;尽管土地利用/覆被类型内部结构变化较复杂、频繁,但各类型之间相互转换的活跃程度逐渐趋于平缓。研究区生态环境质量指数呈增长趋势,年均增长率为0.31%,生态环境逐年改善。致使研究区生态环境质量改善的主要驱动力为气候的变暖湿和土地利用政策的改变。近27 a来,研究区中高山带降水量的增加,扩大了保护区冰川雪地的面积;晋升为国家级自然保护区后的土地利用政策,有效遏制了人类活动对保护区土地利用/覆被的影响,进而使生态贡献率较低的荒地转化为生态贡献率高的林草地,提高了区域生态环境的质量。

In the paper,the land use/cover change and its driving force in Tomur National Nature Reserve were analyzed using GIS technology and the regional eco-environmental quality index,based on the remote sensing data of three phases. The analysis showed that in recent 27 years,glacier and grassland areas had increased with the increasing rates of 12. 37% and 99. 36%; water and desert areas have decreased,with the rates of 23. 07% and 12. 15%,respectively; forest area has decreased by 16. 77% in the early phase and then increased by 57. 91% in the later phase; Regional land use/cover dynamic degree has been 0. 39% in the early phase and 0. 36% in the later phase,with the conversion rate of 21. 95% in the early phase and 18. 91% in the later phase;the conversion rates of water,grassland and forest land have been higher,while those of glacier and deserted land have been lower; in spite of the internal structure changes of land use/cover type have been more complicated and frequent,the active degree of mutual transformation among different land uses/cover types has gradually gentled down. The ecological environment quality in the study area has increased,for example,the regional ecoenvironmental quality index was 0. 479,0. 486 and 0. 518 in 1989,2003 and 2016 respectively. The average annual growth rate has been 0. 31%. The main driving forces for the improvement of the ecological environment quality in the study area are the changes of climate and land use policy. Nearly 27 years,with the increase of precipitation in the middle and high mountain zones in the nature reserve,the area covered by glacier and snow in the nature reserve has been enlarged; the land use policy after the promotion of the National Nature Reserve effectively curb the impact of human activities on land use/cover,thus,the deserted land with low ecological contribution rate has transformed into the forest and grassland with high ecological contribution rate,which has greatly improved the quality of the regional ecological environment.