岷江源头区森林景观动态与土壤侵蚀的关系

Relations between Dynamics of Forest Landscape and Soil Erosion in Headwater Region of the Minjiang River

为了解岷江源头区森林经过变迁对土壤侵蚀的影响,利用遥感和GIS技术分析了岷江源头区的森林景观动态(1974～2002年),应用USLE模型计算该区域同时期的土壤侵蚀变化。近30年来,随着森林景观面积的持续增加,土壤侵蚀量逐渐减少,各景观类型的散布指数也随着土壤侵蚀量的减少而增加。各不同的森林景观控制土壤侵蚀的能力存在差异,针叶林最优,阔叶林次之,针阔混交林最差。森林景观破碎度随土壤侵蚀的增长而增加,分布在较轻侵蚀区中的景观斑块具有更复杂的形状。

By means of RS, GIS and FRAGSTATS, the dynamics of forest landscape in headwater region of the Minjiang River during 1974 - 2002 were analyzed. Calculation of soil erosion in the same period was carried out by USLE model then. Based on the analysis of forest landscape pattern and soil erosion, the relations between dynamics of forest landscape and soil erosion in this region were discussed in class level. As results, there were complicated relations between dynamics of forest landscape and soil erosion. The increase of the area of forests happened with the decrease of annual soil erosion at the same time. The way that forest landscape distributed was related with soil erosion samilarly. Moreover, as to the capabilities on soil erosion control, different forest classes were ordered as following： coniferous forest 〉 deciduous forest 〉 mixed forest. Furthermore, the fragmentation of forest landscape increased by augment of soil erosion. Forest patches located in No Erosion Region and Slight Erosion Region had more complex shape.