考虑滑坡敏感性的天津市蓟州区生态网络构建

随着城镇水平不断提高,人口数量不断增加,滑坡、崩塌等地质灾害频发,天津市蓟州区的景观孤岛化和破碎化现象日益严重,生物多样性减少,生态价值和生态服务功能降低。以天津市蓟州区为研究区,从自然资源、气候调节、水源涵养、生物多样性等方面考虑,选取生态源地;选取坡度、地形起伏度、坡向等滑坡孕灾环境因子,基于信息量模型,在定量分析滑坡与各孕灾环境因子关系的基础上通过地图代数计算滑坡敏感性指数,并用于修正由土地利用类型赋值得到的生态基本阻力面,基于最小费用模型提取研究区生态廊道,进而构建天津市蓟州区生态网络。研究结果表明:研究区内滑坡的空间分布主要受坡度、高程、地形起伏度以及岩土类型等因素的控制;经验证基于信息量模型计算得到的滑坡敏感性指数对研究区内的滑坡具有较强的诊断能力;基于最小费用模型,提取生态廊道23条,总长度约为129 km。通过对比分析,提取的生态廊道基本上避开了滑坡灾害的高敏感性区域,能够有效地将生态源地进行连接;生态廊道在蓟州区的空间分布存在显著的差异,主要分布在蓟州区的北部山区,生态廊道的密度较高,在蓟州区的中部和南部地区,生态廊道的分布非常稀疏。研究成果将为天津市蓟州区生态网络的优化、生态安全格局的构建提供科学依据。

Research on the ecological network construction of Jizhou district in Tianjin

As urbanization level and population rise continuously, landslides, slides and other geological disasters strike very frequently, and in Jizhou District of Tianjin, landscape isolation and fragmentation are getting increasingly serious, biodiversity is on the decrease, and ecological values and service functions are being reduced. In this paper, Jizhou District of Tianjin was taken as a study area. Ecological source regions were selected considering many factors such as natural resources, climate regulation, water conservation, and biodiversity. Slope, relief, aspect, elevation, lithology type, road, fault, and type of land use were taken as landslide susceptibility factors. In virtue of an information value model, quantitative analysis was conducted on the relations between landslides and these susceptibility factors, based on which, landslide susceptibility index was then calculated using map algebra which was used to modify the basic ecological resistance plane was obtained through assignment of the type of land use. Then ecological corridors in the study area were extracted using the minimal cumulative resistance model, after which, an ecological network was constructed for this district. According to the results, the spatial distribution of the landslides in the study area were controlled by slope, elevation, relief and lithology type. The landslide susceptibility index obtained through calculation had relatively strong diagnosibility based on the verification. 23 ecological corridors were extracted, 129 km in total. Comparative analysis indicated that these ecological corridors basically kept away from highly susceptibility areas of landslide disasters and they could connect ecological source regions effectively. In terms of spatial distribution, ecological corridors in this area also showed significant differences. They were mainly distributed in the northern mountainous area of Jizhou district, where the density of ecological corridors was high, while ecological corridors in the central and southern areas were very sparse. The study results will provide Jizhou District of Tianjin with a scientific basis for optimizing its ecological network and constructing an ecological security pattern.