Building and assessing the ecological networks of a cold-region city: A resilience perspective using "urban avoiders" as indicators

Rapid urbanization has accelerated biodiversity loss and ecosystem instability, particularly in ecologically fragile cold-region cities. As a critical node along the East Asian–Australasian Flyway, Harbin provides essential habitats for migratory birds but faces increasing ecological fragmentation. To better understand how urban ecological networks (ENs) respond to disturbances in cold-region environments, this study proposes an integrated framework that explicitly incorporates resilience simulation into EN analysis. Understory insectivorous birds, characterized by high ecological sensitivity and recognized as "urban avoiders", were selected as indicator species to identify key habitats and ecological corridors. ENs were constructed based on species habitat suitability and landscape connectivity analyses, while resilience was evaluated through disturbance-based simulations that examined network responses under targeted and random node removal scenarios. The results indicate that most of the 120 identified ecological sources are distributed along both banks of the Songhua River, Northeast China, and are connected by 280 ecological corridors, including 39 key corridors. A total of 12 key nodes and 25 barrier points were detected, primarily concentrated in the old urban areas in the southern part of the city. Resilience simulations show that targeted disturbances lead to a substantially faster decline in both structural and functional resilience compared with random disturbances. The key nodes located along the Songhua River corridor and in southern Harbin play a critical role in maintaining overall network stability. By linking species-based habitat modeling with disturbance-driven resilience assessment, this study advances the understanding of EN stability in cold-region urban ecosystems and provides practical guidance for biodiversity conservation and sustainable urban planning in cold-region and other ecologically vulnerable cities.