云南纵向岭谷区道路网络对生态系统影响的尺度效应

云南纵向岭谷区具有复杂的生态系统,其生物多样性在全球中具有重要地位,但是由于人类活动的影响,尤其是道路网络的发展及其导致的土地利用变化,使得该地区生态系统退化日益严重.选取2km×2km、4km×4km、6km×6km、… \,20km×20km网格进行多尺度相关分析和方差分析,研究云南纵向岭谷区道路网络与生态系统分布的相关性及其独立和交互作用,分析道路网络对生态系统影响的尺度效应.然后又进一步研究了道路网络和地形因子(比如海拔、坡度和坡向等)对生态系统的独立和交互作用.研究结果表明,道路网络与生态系统分布的相关性与路网等级有关,其相关程度与路网等级呈反比,随着尺度的变化,道路网络与生态系统分布的相关性表现为增强型、减弱型、质变型和无尺度效应这4种类型.在大多数尺度下,道路网络和地形因子对生态系统分布既有独立作用,也有交互作用.其中,高等级路网的独立作用比较显著,而低等级路网的独立作用不太显著.但是,随着尺度的增大,县乡路网、乡村路网和小路网对生态系统分布的独立和交互作用均显著,且表现出高度的相似性,表明地形对低等级道路具有明显的干扰或屏蔽效应.

The multi-scale effect of road network on the ecosystem in Longitudinal Range-Gorge region of Yunnan Province

Longitudinal Range-Gorge Region (LRGR) of YUN Nan Province is characterized with its complex mountain ecosystem and the globally important biodiversity. However, this unique mountain ecosystem is experiencing extensively increased degradation largely due to the human activities, especially the road network development and associated land-use changes. To quantify the effects of road networks on the ecosystem at multi-scales in LRGR of YUN Nan Province, the spatial correlation and ANOVA analysis were conducted between road network density and ecosystem proportional index under different spatial scales varying from 2km×2km to 20km×20km. The independent effects of different grades of road networks and their interactive effects with those topographic factors (i.e. altitude, slop and aspect) on the ecosystem in LRGR were further explored. The results showed that the correlation between road network density and ecosystem distribution was mainly determined by the road networks grades with the tendency that correlation decreased with upgrading of the road networks, and the scaling effects of the road networks can be divided into 4 categories: rising, descending, mutation and unscaled. The interactive effects between the road networks and the topographic factors occurred at most scales, implicating that both of them affected the ecosystem distribution. The independent effects of high-grade road networks were more prominent than that of low-grade road networks. The independent effects of low-grade road networks (i.e. county road and trail) and their interactive effects with topographic factors were mostly notable with extremely similar changes of scaling-up, indicating that the effects of low-grade road networks were much extensively but largely mitigated by those topographic factors.