基于分形理论的路域植被生态系统空间异质性研究

Study on spatial heterogeneity of road-region vegetation ecosystem based on fractal theory

通过实地观测获取南京市路域植被情况数据,对草类、灌木类、乔木类3种不同植被类型图斑形状指数标度-频度关系、自相似分形特征及决定系数进行网格法分析。在此基础上,通过变异矩阵分析、分维计算等方式,对满足分形特征的不同道路和坡向的路域植被进行植被配置合理性、空间异质性和生态稳定性的对比分析和量化考察。应用空间异质性理论与分形理论,将网格法与变异函数法结合,依次分析标度-频度关系、分形特征、空间异质性,准确计算出路域植被的分维指标数据。结果表明:连续的道路路域各植被类型存在标度-频度关系和自相似分形特征,分维指标可以准确定量地评价路域生态系统的空间异质性与生态稳定性。

In this paper,road-region data of selected urban roads in Nanjing city was collected by means of field survey.The pots shape index scale-frequency relation,the self-similar fractal characteristics and the determination coefficient of three vegetation types of grass,shrubs and trees were analyzed with grid method. Based on the analytical results,the roadregion vegetation ecosystem accorded with the fractal characteristics was studied by means of semi-variogram analysis and fractal dimension calculation. The rationality of vegetation arrangement,the spatial heterogeneity and the ecosystem stability of vegetation were analyzed comparatively and quantitatively for different road-region and slope directions. In this paper,the fractal and spatial heterogeneity theories were applied to study the vegetation landscape of the road-region ecosystem. The grid method and the semi-variogram method were combined to apply to the analysis. The scale-frequency relation,fractal characteristic and spatial heterogeneity was analyzed. These leaded to an accurate calculation result of fractal index of road-region vegetation. The result showed that the pots shape index scale-frequency relation and self-similar fractal characteristics existed in continuous road-region vegetation. Fractal dimension could accurately and quantitatively value the spatial heterogeneity and ecosystem stability of road-region ecosystem.