Regional planning for ecological protection of rivers in highly urbanized areas

The ecological risks associated with rapid urbanization have seriously undermined the river's ecological security. Especially for developing countries, the weak ecological foundation and enormous population pressure have increased the difficulty of river ecological protection. It is urgent to propose a bottom-line planning and man-agement approach for river ecological protection in highly urbanized areas of developing countries. We quan-tified the minimum cumulative resistance of the river protection and construction land expansion processes. Then, based on the difference between these two minimum cumulative resistances, we assessed the river ecological risk in the Beijing plain area and presented a complete method to regional-level planning and man-agement for river ecological protection. The results show that: 1) The spatial distribution of river ecological risks follows a three-tier ring structure, decreasing from the city center to the suburbs and then to the outer suburbs. The number of river segments with ecological risk levels 1, 2, and 3 are 44, 42, and 23, respectively, accounting for 39.2% of the total length of all river sections, which indicates that a larger number of rivers are facing high ecological risk. 2) The study area was divided into three zones according to the suitability of river ecological protection, with 2476.89, 765.51, and 3832.09 km2, respectively. Zone I and Zone II can be developed as pro-tection nodes and riparian protection zones to develop the river ecological network in the central city. 3) We extracted 133 large ecological patches and 219 potential ecological corridors, which should be connected with the river network to enhance the connectivity of the local ecological landscape. The complete method proposed in this study is more focused and implementable to assist administrators in protecting and restoring the ecological security of urban rivers.

Automated summary

The ecological risks caused by rapid urbanization have severely impacted the ecological security of rivers, especially in developing countries with weak ecological foundation and high population pressure. An urgent need exists for a comprehensive approach to planning and managing river ecological protection in highly urbanized areas of developing countries. This study quantifies the minimum cumulative resistance of river protection and land expansion, assesses river ecological risks, and proposes a method for regional-level planning and management of river ecological protection. The results show the spatial distribution of river ecological risks and recommend protection zones and riparian areas to enhance the connectivity of the local ecological landscape through the river network. The proposed method provides a focused and implementable strategy for administrators to protect and restore the ecological security of urban rivers.