基于GIS和RUSLE模型的万州区土壤保持服务功能空间分布特征

土壤保持服务是重要的生态系统服务之一,代表生态系统对土壤侵蚀所起到的削减和改善作用。以万州为研究区,基于GIS平台和修正通用土壤流失方程(RUSLE),运用降雨、DEM等数据建模,探讨万州区土壤保持服务功能的空间分布特征并分析其影响因素。结果显示:(1)万州区土壤保持总量为1 435.84×10~5t/a,单位面积年均土壤保持量为417.91 t/(hm~2·a),具有较高的土壤保持服务功能重要性;(2)土壤保持服务空间分布受地形和人类活动等的显著影响,东南部山地区域较高,而铁峰山与方斗山之间的长江河谷较低,其空间分布特征与土壤侵蚀的分布状况大致相反;(3)坡度角度,15°~25°坡度区产沙量最大占全区的41.56%,8°~15°区域次之,这两个坡度区人地矛盾最为集中;土地利用类型中,旱地侵蚀最为强烈,而林地侵蚀微弱并表现出很高的土壤保持服务功能。研究结果对万州乃至整个三峡库区的水土保持工作有借鉴意义。

SPATIAL DISTRIBUTION CHARACTERISTICS OF SOIL CONSERVATION SERVICE IN WANZHOU DISTRICT BASED ON GIS AND RUSLE MODEL

Soil conservation service is one of the most important ecosystem services,which represents the positive function of ecosystem to reduce soil erosion.Data from WanZhou District including precipitation,soil characteristics,DEM et al.,based on revised universal soil loss equation(RUSLE) and GIS method was used to investigate the spatial distribution characteristics of soil conservation service.and the influencing factors.The results showed that the total soil conservation capacity and mean soil conservation capacity were 1 435.84× 105 t/ a and 417.91 t/(hm2 · a),indicating a great significance of soil conservation service.In further,spatial distribution of soil conservation service was mainly influenced by terrain and human activities.Soil conservation was high in southeastern mountain area,and low in the Yangtze river valley between Tiefeng mountain and Fangdou mountain,;while soil erosion showed the opposite spatial distribution characteristics.A slope of 15-25 degree owned the largest erosion,contributing 41.57％ of the total erosion amount,and a slope of 8-15 degree ranked the second,with concentrated contradiction between human and land.In terms of land type,dry land region was the main source of erosion,and woodland area showed high soil conservation service.There is a strong need for changing land use and taking measures such as returning farmland to forest to improve the level of soil conservation service.The results can give support to control soil erosion and improve soil conservation service in Wanzhou District and Three Gorges Reservoir area.