海河流域河流生境功能识别及区域差异

城市群快速发展严重影响着区域水生态系统的完整性,大尺度流域的河流生境功能辨识和分析尚缺乏系统研究。以海河流域为例,根据河段蜿蜒度、河段比降、断流风险、盐度等4个指标,构建了河流生境功能的分类指标体系。通过多源空间数据和人工判读,划分了6254条河段,在此基础上将河流生境类型划分为15类。通过52个监测样点的鱼类调查数据,分析了不同河流生境的水生生物特征差异,揭示了鱼类多样性高的区域多位于河流比降大、断流风险低的区域,而河流蜿蜒度对于鱼类多样性影响较小。根据京津冀13个地级市的河流生境差异,提出京津冀城市群的生态安全构建需要充分考虑河流生境的空间异质性,并制定融合城市发展目标、水资源利用需求和河流生境功能的综合指标体系。

Identification of aquatic ecosystems and regional characteristics in the Haihe River Basin, China

The integration of aquatic ecosystems is significantly affected by the increasing population and urbanization of megacity regions. Currently, studies on river habitats are mainly focused on local watersheds. However, systematic research on the identification of river habitats in large watersheds is lacking. Here, we developed an identification method based on four indicators, including river curve degree, elevation gradient, dry-up risk, and salinity. Detailed spatial data is required to classify river habitats. We extracted 6254 river sections based on current digital data and experience, and the total rivers were then classified into 15 types using the four indicators and these 6254 river sections. Fish diversity was used to assess the heterogeneity of river habitats. We sampled fish from 52 river sites, quantified their species, and determined the degree of biodiversity. The results showed that: (1) fish diversity is determined by the river elevation gradient and dry-up risk. A river with a high elevation gradient has high fish diversity as well as low dry-up risk. (2) The curve degree of rivers has little influence on fish diversity. This study found that the river''s habitat is not dependent on the utilization function of water resources in the Beijing-Tianjin-Hebei megacity region. Water resource preservation zones should be improved by considering river dry-up risks in this region. The water ecological security patterns should be developed based on multiple sources of knowledge of the water utilization function, city development plan, and river habitat characteristics.