退耕还林背景下泸水市生态环境质量遥感动态变化

Remote Sensing Evaluation of Ecological Environment Quality in Lushui City Under the Influence of the Conversion of Cropland to Forest Project

为了深入了解退耕还林工程实施背景下的生态环境质量时空变化规律,基于2001—2018年Landsat TM/OLI遥感影像,选用遥感生态指数评价模型(RSEI),开展泸水市生态环境质量动态变化研究,并在此基础上分析了生态环境质量变化与退耕还林工程的相互关系。结果表明:(1)2001年、2006年、2013年、2018年泸水市RSEI均值分别为0.750,0.759,0.667,0.683,生态环境质量总体波动下降。分级处理后,当地生态环境质量由“较差”、“中”、“良”等级主导,占比之和达97%以上。(2)泸水市生态环境质量空间分布与高山峡谷的地形特征吻合,怒江两岸RSEI等级区域表现出东西对称性。在变化上,怒江水系河谷地带生态环境显著恶化,中高山地区则有所改善,叠加人类活动空间分布发现人类活动是导致当地生态环境质量整体下降的重要原因。(3)泸水市退耕还林工程效果显著,2001—2018年耕地减少了24%,其中又有64.74%坡度大于25°。两轮退耕还林工程期间的各乡镇退耕还林率与RSEI变化的相关性较高,相关系数分别达到0.767,0.817,表明退耕还林对当地生态环境产生着积极影响。

In order to understand the spatial and temporal variation of ecological environment quality in the context of the implementation of the fallow forestry project,based on Landsat TM/OLI remote sensing images from 2001 to 2018,the Remote Sensing Ecological Index(RSEI)was selected to carry out a study on the dynamic changes of ecological environment quality in Lushui City,and to analyze the interrelationship between ecological environment quality changes and the Conversion of Cropland to Forest Project on this basis.The results show that:(1)The RSEI values of Lushui City in 2001,2006,2013 and 2018 were 0.750,0.759,0.667 and 0.683,respectively;the overall quality of the ecological environment showed the downward trend in fluctuations;after the graded treatment,the ecological environment quality was dominated by‘poor’,‘medium’and‘good’grades,which accounted for more than 97%of the total;(2)the spatial distribution of ecological environmental quality in Lushui City was coincident with the topographical features of the alpine canyon;The RSEI grade areas on both sides of the Nujiang River exhibited east-west symmetry;in terms of changes,the ecological environment in the valley of the Nujiang River system has deteriorated significantly,while the middle-high mountain areas have improved;after superimposing the spatial distribution of human activities,human activities were found to be the important cause of the overall decline in the quality of the local ecological environment;(3)Lushui City′s Conversion of Cropland to Forest Project had achieved remarkable results,with a 24%reduction in farmland between 2001 and 2018,of which another 64.74%had slopes greater than 25°.The cumulative change in the areas of Conversion of Cropland to Forest Project and the changes in RSEI were highly correlated with correlation coefficients of 0.767 and 0.833.It is shown that the Conversion of Cropland to Forest Project has a positive impact on the local ecological environment.