Temporal dynamics of bird species-habitat networks on forested islands

Habitat fragmentation reshapes species spatial distributions and community dynamics. Species and their occupied habitats form associations that can be quantified as bipartite networks to reveal how community structure is maintained through spatiotemporal dynamics of these associations. However, most network studies are limited to static snapshots, failing to capture the temporal variation in network properties and the relative contributions of species turnover and spatial rewiring in network dynamics. Here, we used a 15-year dataset (2009–2023) collected annually via standardized line-transect surveys during the breeding season across 36 islands in the Thousand Island Lake (TIL), and investigated the temporal dynamics of species-habitat networks by β - diversity decomposition. Our results showed that while the network properties (connectance, nestedness, and modularity) remained relatively stable over 15 years, this consistency masked intense internal reorganization of species-habitat associations. Temporal network dissimilarity increased with temporal interval and was predominantly driven by spatial rewiring (due to spatial redistribution of persisting species) across all time scales. Our findings suggest that ecological responses of communities to fragmentation are scale-dependent in both space and time, as evidenced by divergent trends in network metrics among islands of various sizes and distinct structural dynamics across temporal scales. Our study underscores the importance of long-term monitoring for detecting structural shifts in species-habitat networks at the decadal scale to inform effective conservation strategies.