北方土石山区土壤侵蚀强度垂直景观格局——以沂蒙山区为例

Vertical landscape pattern on soil erosion intensity in the rocky area of northern China: A case study in the Yimeng Mountainous Area,Shandong

以具北方土石山区典型特征的沂蒙山区为例,在分析土壤侵蚀过程的基础上,选取具生态学意义的侵蚀强度景观格局指数,从垂直维度上分析侵蚀景观格局变化特征。结果表明:土壤侵蚀景观格局具有显著垂直分带性。50～200带为低侵蚀稳定区,人类活动影响大,缀块成片分布,连通性强,形状较规则;400～800带为高侵蚀稳定区,自然因素起主导作用,缀块密度大且分散,形状较复杂;200～400带为侵蚀景观急剧变化区,侵蚀程度随高程增加而增大,自然因素作用增强。微度与轻度侵蚀景观、强烈与极强烈侵蚀景观具相同垂直变化趋势,此两组侵蚀景观变化趋势的差异主要分布于低于300带和高于500带处;中度侵蚀景观变化趋势可视为前两组侵蚀景观变化趋势的过渡。

This paper takes the Yimeng Mountainous Area,one of the most typical regions of the rocky area in northern China,as a case study.There are relatively few studies on the soil erosion monitoring and modeling in this region.According to the national professional standard of SL 190-2007 Standards for Classification and Gradation of Soil Erosion,this study aims to explore the characteristic of the vertical landscape of soil erosion in the vertical belts with each having an interval of 50 m,supported by the technology of GIS and RS and the data of Landsat TM image and relief map.Based on the analysis of the ecological process of soil erosion,this paper selects the proper landscape indexes,including area,patch density,aggregation index and perimeter-area fractal dimension. The result shows that there are evident laws in the vertical landscape of soil erosion.In the landscape level,PD and SEI（Soil Erosion Index） increase at first and then decrease with the rise of the elevation,while AI is on the contrary,and D increases continually.So two relatively stable elevation ranges and one dramatic change range can be identified.The region between the belts of 50 and 200 was regarded as one stable area with low erosion intensity,in which patches are featured by low fragmentation,high connectivity and regular shape,indicating human activities emerged on the landscape.And the other stable area was in the range of 400 to 800 belts,where natural factors dominate the landscape with high patch density,low aggregation and irregular shapes.The soil erosion landscapes changed dramatically in the area ranging from 200 to 400 belts,and with the rise of elevation,the effect of natural factors were increased rapidly.In the class level,the landscape pattern changed differently.The soil erosion landscapes of the minimal and slight intensity have the similar trend with the rise of elevation,and that of the intensity of intense and very intense were almost the same,and the difference between the above two changing trends mainly exists in the area lower than the 300 and the area higher than the 500 belt.The landscape of moderate soil erosion intensity can be considered as the transfer regime between those of the two categories mentioned above.