Enhancing construction of ecological security pattern through a wetland waterbird protection approach: A case study of Yellow River Basin in Shandong Province, China.

To enhance the ecological security level and protect species diversity in the Yellow River Basin of Shandong Province, we took the nine cities along the Yellow River in Shandong Province as the research area, and selected , , and as indicator species of waterbirds. We identified ecological sources using morphological spatial pattern analysis, and utilized the maximum entropy model to analyze the suitability and the contribution degrees of different climate factors for the distribution of waterbirds and to explore the overlap proportions between the high suitable habitats of species and ecological sources. Then, we revised the index system of resistance factors based on the contribution degrees of climate factors. Combined with the circuit theory, we extracted ecological corridors and ecological pinch points to construct the ecological security pattern of the Yellow River Basin in Shandong Province. The results showed that, considering the needs of ecological land for waterbirds, the total area of identified ecological source area was 2922.22 km, including water source area 1362.61 km, forest and grassland source area 1559.61 km. Overall, the ecological sources presented a spatial pattern characterized by "more in the east and less in the west, connecting rivers and the sea". The areas of the highly suitable habitats predicted for , , accounted for 33.4%, 13.0%, 10.9%, and 14.1% of the total area, respectively. Among them, the overlap rates between the comprehensively predicted highly suitable habitats for waterbirds with the areas of water sources and forest and grassland sources were 44.4% and 6.0%, respectively. A total of 390 ecological corridors were constructed, including seven key conservation corridors that connected the key habitats and potential habitats of waterbirds, with 20 ecological pinch-points distributed in coastal areas, forests in central areas, and the main-stream area of the Yellow River. From the perspective of wetland waterbird conservation, we proposed the "two belts, three zones, and two points" planning framework and optimization strategies, aiming to provide theoretical support for coordinated ecological protection and biodiversity governance in the Yellow River Basin of Shandong Province.