Constructing wetland ecological corridor system based on hydrological connectivity with the goal of improving regional biodiversity.

Hydrological connectivity is crucial for the healthy operation of wetland ecosystems. However, the current design of ecological corridors in wetland biodiversity networks is mostly based on species migration resistance, neglecting the important role of hydrological connectivity. How to incorporate hydrological connectivity into the wetland ecological corridor system (ECS) is still unclear. To answer the question, we proposed a framework for constructing a wetland ECS with the goal of improving conservation value of previously identified wetland biodiversity hotspots based on hydrological connectivity. In the proposed framework, we clarified the function-level-dimension of each corridor based on the dynamics of conservation value of biodiversity hotspots, the hierarchical classification of rivers and the dimension of hydrological connectivity. Then we determined the spatial distribution and functional zoning of the corridors by least cost model (LCM) using indicators that reflect wetland hydrological connectivity resistance, including water coverage, water use efficiency of vegetation, and land use suitability. The results are as follows: (1) to improve the overall hydrological connectivity and conservation value of biodiversity hotspots, 25 corridors should be constructed for vertical hydrological connectivity (with 3 for maintaining the status quo, 6 for improving and 16 for restoring connectivity) and 3 corridors should be constructed for lateral hydrological connectivity; (2) total area of all corridors are 11 km, accounting for 6.79% of the study area (2.47% of core zone and 4.32% of buffer zone); (3) low suitability areas of hydrological vegetation gradient (HVG) are the most extensive, followed by low suitability areas of land use/cover change (LUCC) and the average fraction coverage of water surface (AFCW), accounting for 65.08%, 47.87% and 6.76% of the corridor coverage, respectively. The proposed framework of constructing wetland ECS in this study has the potential to provide the post-2020 global biodiversity framework and sustainable development goals with specific technical support and more targeted-control strategies for building a hydrological connected wetland biodiversity network.