三峡库区腹地典型流域不同坡度带上的土壤侵蚀多样性变化-以梅溪河流域为例

摘要

[目的]通过对三峡库区梅溪河流域土壤侵蚀多样性的分析,以期为研究区生态环境治理与保护提供依据.[方法]以三峡库区梅溪河流域为研究对象,在GIS技术支持下,以1988年、1999年、2010年TM影像为数据源,提取梅溪河流域不同坡度各土壤侵蚀类型面积,计算出土壤侵蚀多样性与均匀度指数.[结果]随坡度的增加,土壤侵蚀强度、多样性与均匀度指数均以25～35°坡度带为转折点呈先增后减的变化趋势.[结论]①因研究区主要为微度侵蚀及轻度侵蚀占流域总面积最大且最大比重达15.57％,土壤侵蚀多样性与均匀度指数在5～35.坡度带增加表明侵蚀强度增强、侵蚀类型更为均匀、生态环境破坏程度加重,在＞35.坡度带指数减小表明侵蚀强度减轻、环境得到恢复与改善.②土地利用分布及其变化与土壤侵蚀多样性和均匀度指数的关系密切.③土壤侵蚀问题虽得到缓解,但土壤侵蚀多样性与均匀度指数变幅均不超过0.02,表明三峡库区土壤侵蚀治理强度仍需跟进.%The diversity of soil erosion in the Meixi River watershed of the Three Gorges Reservoir Region was analyzed,in order to provide references for governance and protection of ecological environment of the study area.[Method]The soil erosion diversity index and evenness index of the Meixi River watershed in the Three Gorges Reservoir Region were studied based on the TM images in the year of 1988,1999 and 2010,supported by GIS technology to extract various types of soil erosion in the area with different slope gradients and calculate soil erosion diversity index and evenness index.[Result] As slope gradients grew,the diversity index and evenness index of soil erosion decrease after increasing with a turning point from 25° to 35°.[Conclusion] The proportion of light-erosion in the study area is 15.57％.Hence,the increase of diversity index and evenness index with gradients of 5°-35° shows that the higher erosion intensity,the more uniform erosion types and the indexes decreased in gradients higher than 35°,suggesting that the lower erosion intensity,the better environment.Distribution and variation of different land types have close relation with soil erosion diversity and evenness indexes.Though soil erosion problems have been alleviated,by comparing soil erosion diversity index and evenness index,it can be concluded that changes of indexes are lower than 0.02,and soil erosion should be continued to be well controlled.