坡面植被斑块水土保持功能的景观图谱表达

Landscape Mapping Expression of the Soil and Water Conservation Function of Slope Vegetation Patch

本文基于景观生态学格局与过程关系研究的定量思维,以地学信息图谱的图形思维方式反映植被空间格局和水土流失过程的关系,以河岸植被缓冲带水土保持功能为例,在构建坡面植被分布格局的景观图谱序列的基础上,利用渗透指数指示植被水土保持功能,分析不同植被格局下水土保持功能的变化,对坡面植被格局的水土保持功能进行景观图谱表达。结果表明,在斑块位置、方向、聚集程度、镶嵌方式4种植被斑块分布类型中,在相同植被盖度下,斑块方向和聚集程度是控制水土流失的有效格局。通过对比不同植被分布类型的渗透值表明,植被分散于坡底并沿等高线方向或者与水流平行的方向分布时水土保持效果较好。本研究结果可为坡面植被水土保持效益的识别、提高提供重要参考。

According to the quantitative thinking in landscape ecology to reveal the relationship between landscape pattern and process, and the graphical thinking in Geo-Info-Spectrum to reflect the relationship between vegetation pattern and soil erosion process, we analyzed the variations in soil and water conservation function of the riparian vegetation buffer zone under different vegetation patterns in spectral sequence, via constructing landscape sequence for the slope vegetation pattern and the leakiness index. The results indicated that patch orientation and aggregation degree were the efficacious landscape patterns in controlling water and soil loss among the 4 distribution types（position, orientation, aggregation degree, and mosaic pattern） of vegetation patch under the same vegetation coverage. Comparison of different distribution types in terms of leakiness value indicated that, when conducting the vegetation restoration measures for the riparian vegetation buffer zone, it is better to arrange vegetation along the contour line or parallel with the river at slope bottom position dispersedly. Results from this study can provide important reference for identifying and improving the soil and water conservation efficiency of slope vegetation.