基于乡镇尺度的土地生态安全时空格局评价研究——以博尔塔拉蒙古自治州为例

摘要

Regional land ecosystem is facing deterioration from the rapid growth of urbanization.In order to promote sustainable development of the land ecosystem,it is necessary that we evaluate regional land ecological security.Many researchers have studied and evaluated for regional land ecological security;however,most of the evaluation was based on watershed and county scale,and few researches focused on the township scale.In this study,Bortala Mongolian Autonomous Prefecture (i.e.Bortala) in Xinjiang Uygur Automous region was taken as study area,and Remote Sensing (RS),Geographical Information System (GIS),and Global Position System (GPS) technologies were adopted to analyze temporal and spatial perspectives of land ecological security in Bortala.On the basis of the natural geographic features and socioeconomic situation of Bortala,we constructed the pressure-state-response (P-S-R) land ecological security evaluation model (township scale) in Bortala.Based on the two period's data of statistic yearbook and remote sensing in 2011 and 2014,we first constructed the index system,using 25 indices reflecting regional P-S-R.The entropy weight and analytic hierarchy process methods were used to determine the indices weight of Bortala P-S-R model.Finally,the land ecological security index of Bortala was calculated with the data obtained from the P-S-R model by GIS Grid.The results show that:(1) The land ecological security index had deteriorated from 2011 to 2014 in Bortala.Between 2011 and 2014,2555.33 km2 of level III(grade of security) transferred to level IV,which deteriorated areas mainly concentrated in Wenquan County;1356.53 km2 of level V transferred to level IV,which improved areas concentrated in the Mangding town and Tuotuo town of Jinghe County.(2) The land ecological security index of most towns was at level III in Bortala,which respected the ecological structure of these towns were not stable.(3) The spatial difference of land ecological security index was obvious in Bortala,the worst places were located in the eastern desert,and the best places were concentrated in the central oasis and lake.The evaluation results and major environment problems may help the local government finding inappropriate and inadequate for Bortala development.Bortala Prefecture is a drought-prone and ecologically vulnerable region in the Northwest region.Temporary land use regulation cannot guarantee long-term regional ecological balance and security.In this study,we recommend increased attention on regional ecological protection and sustainable development for villages and towns.%近年来,国内外学者已做了大量区域土地生态安全评价的研究,但大多针对流域或县级以上行政单元,乡镇尺度的土地生态安全评价研究甚少.因此,选择地处我国西北干旱生态脆弱区的博尔塔拉蒙古自治州为研究区,以“3S”技术和数学统计方法为支撑,结合研究区自然地理特征和社会经济状况,构建博尔塔拉蒙古自治州乡镇级压力-状态-响应(Pressure-State-Responses,P-S-R)土地生态安全评价模型,并对其土地生态安全空间格局特征及成因进行诊断性分析.结果表明:(1) 2014年博州土地生态安全较2011年有所恶化,Ⅲ级向Ⅳ级转化的面积最大,高达2555.33 km2,主要在温泉县境内,其次是V级区域向Ⅳ级转化1356.53 km2,主要发生在精河县的茫丁乡和托托乡;(2)博州大部分乡镇的土地生态安全状况处于Ⅲ级水平,区域生态结构不稳定,亟待调整;(3)博州土地生态安全状况具有明显地域性分布的特征,低值区多集中于博州东部荒漠地区,高值区多集中在博州中部绿洲区域和湖区.研究结果可为乡镇级土地生态安全评价提供参考,为区域生态保护协调推进与乡镇可持续发展提供理论指导.