道路网络对黄土高原过渡区土地生态安全的影响

Effects of Road Networks on Land Ecological Security: A Case Study in a Transitional Area of the Loess Plateau

作为生态脆弱区,黄土高原及其风沙过渡区不合理的土地利用和人类干扰是造成土壤侵蚀、土地退化加剧的主要原因,而道路网络作为人类干扰的途径,贯穿于各类景观,其存在和发展产生了许多生态效应,同时对土地生态安全产生影响。在分析道路对景观影响的基础上,论述道路网络和土地生态安全的关系,基于生态效应,从格局和过程研究入手,提出基于格局和过程的生态安全指数,综合评估道路网络潜在生态影响及累积性后果,进而分析道路网络对典型脆弱区生态安全的影响。以陕北横山县为研究区,利用GIS分析道路网络对区域生态安全的影响,结果表明,道路所造成的生态安全在空间尺度上差异较大,道路密度和生态安全水平具有较高的负相关。

Irrational land use and human disturbance accelerate soil erosion and land degradation in the areas with vulnerable ecology in the transitional zone between the Loess Plateau and the Mu Us Sandland. In this paper, the effects of road networks on the ecological security in this transitional zone in north Shaanxi Province are researched. In the study, the difference in terrain, landforms, ecosystems and landscapes is significant, the ecological environment is vulnerable and is strongly affected by human activities. Road construction in the study area has the social effects and economic returns, especially affects significantly the ecology. As widespread features of landscapes and human disturbance paths, road networks bring about many ecological effects and affect the regional land ecological security. Focused on the impact of road networks on landscapes, in this paper the relationship between road networks and land ecological security is discussed. Based on the different ecological patterns and processes, the pattern- and process-based ecological security indexes are put forward, and then the various potential and accumulative ecological effects of road networks are comprehensively assessed. Furthermore, the effects of road networks on land ecological security are analyzed. A case study on the road effects on land ecological security in Hengshan County in north Shaanxi Province is carried out. The results show that the spatial difference of ecological security affected by roads is significant, and there is a high negative correlation between the road density and the ecological security level.