Landscape configuration as a driver of shorebird use in artificial high-tide roosts: evidence from a key stopover site in the East Asian–Australasian Flyway

The Yellow Sea–Bohai Gulf coasts support millions of shorebirds along the East Asian–Australasian Flyway (EAAF), but natural high-tide roosts (HTRs) have degraded sharply due to reclamation, dikes and disturbance, forcing birds to use suboptimal artificial habitats. To inform evidence-based HTR restoration, we surveyed shorebird communities at two restored HTRs in southern Jiangsu, China (2021–2024), and analyzed spatiotemporal dynamics and drivers via aligned rank transform ANOVA (ART-ANOVA), generalized additive models (GAMs), and hierarchical partitioning (HP). Abundance and species richness peaked in early May and August–early September, with significantly higher values in autumn than spring. Migratory phenology contributed the highest independent explanatory power to community dynamics, followed by landscape factors. Notably, in the study region, a well-configured 48-ha restored HTR temporarily supported more than180,000 shorebirds during spring tides while sustaining high functional richness (FRic). Within the observed empirical gradient across our study sites, higher mudflat dominance (observed MLPI up to 48.6%) and complex patch shape (PAFRAC up to 1.4) both positively correlated with abundance and richness. Simultaneously, lower water patch cohesion (WCO down to 98) correlated with higher richness and FRic, a relationship we hypothesize may reflect microhabitat heterogeneity. Our findings provide a practical regional reference for HTR management in the Tiaozini wetland and a conceptual framework for the broader Yellow Sea–Bohai Gulf. Given the site-specific nature of these results, future cross-regional validations across multiple restored HTRs throughout the EAAF are required to assess transferability and inform context-tailored restoration interventions.