作　　者： ; ; ; ; ;

机构地区： 中国科学院

出　　处： 《生态学报》 2014年第23期7101-7109,共9页

摘　　要： 鼠害大暴发年份对受害植被分布和受害等级的快速评价,对于鼠害防治和恢复农业生产具有重要意义。研究以洞庭湖北洲子区域东方田鼠(Microtus fortis)为例,提出通过分析植被指数变动规律以确定评价时间的方法,通过植被指数对鼠害的敏感性分析,选择增强型植被指数(Enhanced vegetation index,EVI)为适宜植被指数,0.07为具有代表性的灾害阈值。运用植被指数差值法获得研究区作物危害分布图与危害等级分布图,表明东方田鼠危害区具有聚集和离大堤一定距离的特点。比较洞庭湖区实地踏查获得的东方田鼠危害图与灾害阈值确定的危害像元分布图,表明基于MODIS(Moderate-resolution imagine spectroradiometer)植被指数的鼠类暴发年份评估方法准确可行。 It is very important to develop a rapid algorithm for rodent pest damage estimation,especially for an outbreak year. The Yangtze vole( Microtus fortis) has been identified as a primary rodent pest in the Dongting Lake region. In July2007,there was a sudden population explosion in that region,representing the most serious Yangtze vole disaster on record.More than two billion voles crossed the lake levee,causing massive crop damage. The study area of Beizhouzi,to the west of East Dongting Lake,was selected because it had the highest population density during the outbreak year. A difference method of vegetation index was used in the assessment,in which the outbreak year 2007 was contrasted with 2004,which was considered a normal year. All vegetation-index imagery was from the Moderate Resolution Imaging Spectroradiometer( MODIS),which was masked by a land-use map of the study area to remove water bodies and urban and built-up lands.The Normalized Difference Vegetation Index( NDVI) in the outbreak year declined during the vegetation growth period,in contrast with the normal year. This NDVI change was a result of plant destruction by the Yangtze vole population. Regarding the local crop system,Julian days 193 and 209 were chosen for observations representative of before and after the Yangtzevole problem. Performances of the NDVI and enhanced vegetation index( EVI) were analyzed. ΔVI was defined as the ratio of a seasonally detrended vegetation index( VI) reduction before and after the Yangtze vole problem to seasonally detrended VI before the problem. Given the mean ΔVI,shift amplitude( the difference of ΔVI between 2004 and 2007),statistical dispersion( inter quartile range( IQR) of ΔVI in 2007),and percentage of detected damaged pixels,the damage threshold was defined as the sum of the mean ΔVI and mean absolute deviation. These were calculated to evaluate sensitivity of the vegetation index. The EVI was selected as the optimal vegetation index for detecting damaged area after sensitivity analysis.An ΔEVI of 0

关 键 词： 危害评估 鼠害 植被指数 遥感

领　　域： [农业科学] [农业科学]