社会-生态系统视角下沙漠化逆转定量评价——以宁夏盐池县为例

摘要

The assessment of socio-ecological systems can reflect the effects of nature,social economics,and human activities on the ecological environment,which is helpful to understand the context of complex social-ecological systems.Desert areas are ideal for socio-ecological system assessments because the land cover of deserts seriously influences the improvement of the local ecological environment and social economy.Yanchi County in the Ningxia Hui Autonomous Region is a typical desertification area where the ecological environment is very fragile.The government has implemented the Grain for Green Project and a prohibited-grazing policy to suppress and reverse desertification since 2000,and these ecological policies have positive effects on ecological restoration of desert areas.Therefore,it is very important to control desertification and maintain the normal function of local social-ecological systems.In this paper,the social-ecological system disturbance in Yanchi County was analyzed to understand the changes of the local social-ecological system.The MODIS (Moderate resolution Imaging Spectrometer) normalized difference vegetation index (NDVI) data of the study region was applied to investigate the spatial distribution of the existing social-ecological system disturbance during 2000-2015.In addition,moving window computational algorithms were used to calculate social-ecological system disturbance intensity and connectivity at different spatial scales.The results showed that (1) the disturbance had different spatial distributions over different periods,and strong disturbances were mainly distributed in southern Yanchi County during 2000-2004,whereas strong disturbances were distributed in the northern and central areas during 2004-2008.Furthermore,strong disturbances were detected in three small areas:southeastern,central,and western Yanchi County during 2008-2012.Moreover,the proportion of strong disturbances in the North showed an increasing trend.Strong disturbances were mainly distributed in the north,mid-west,and northwest of the county during 2012-2015.(2) There was a significant difference of disturbance intensity and connectivity of social-ecological systems at multi-scale levels.The types of clusters changed with the increase in the study window:lower disturbance discrete types converted to lower disturbance concentration types,and higher disturbance concentration types converted to lower disturbance discrete types.(3) Overall,except in some small areas,the disturbance intensity and connectivity of social-ecological systems were generally not large in most regions of Yanchi County.However,the desertification management is still insufficient,and the government should implement additional active policies to control desertification in the future.%对沙漠化逆转区进行有效管理是沙漠化治理至关重要的环节,研究沙漠化逆转区社会-生态系统的干扰状况可以为沙漠化逆转区的管理提供理论支持.基于MODIS NDVI产品数据,用移动窗口法则计算了不同空间尺度上盐池县社会-生态系统的干扰强度和干扰连通度,并分析了2000-2015年间不同时间段内宁夏盐池县社会-生态系统干扰的空间分布.结果表明:①盐池县不同时间段内社会-生态系统干扰的空间分布具有较大差异,200-2004年强干扰主要集中于盐池县的南部;2004-2008年强干扰在北部、中部均有表现;2008-2012年强干扰分别位于东、中、西3个小区域,并没有集中于一个区域,且北部强干扰区域进一步增强;2012-2015年强干扰的区域主要集中于县域的北部、中西部和西北部.②不同空间尺度上社会-生态系统干扰强度和连通度有很大差异,随着移动窗口的增大,不同集群的干扰类型也发生了变化,主要表现为低干扰离散型向低干扰集聚型转变,高干扰集聚型向低干扰离散型转变.③总体上看,除了个别区域社会-生态系统干扰强度和连通度较大以外,盐池县大部分地区社会-生态系统受干扰的强度和连通度并不大,沙漠化逆转程度较低,还有待进一步加强沙漠化治理力度.