Dynamic conservation under shared pressures: Apparent stability masks species‐specific redistribution in staging shorebirds

Conservation planning often relies on community‐level indicators including total abundance, distribution centroids and migration timing. However, in multispecies systems, these aggregate metrics can mask species‐specific redistribution under shared pressures, creating a misleading impression of stability and obscuring where and for which species management is most needed. Using standardized spring (March to May) shorebird counts from 2016 to 2024 at six major staging sites of the southern Yellow Sea, we quantified interannual trends in staging totals (bird‐days), abundance‐weighted latitudinal centroids and staging timing, and tested whether redistribution was better associated with population trajectory than with biogeographic or morphological correlates. Despite their smaller intertidal extent, the northern Jiangsu estuaries emerged as the central staging region: mollusc densities were more than an order of magnitude higher there, and the area‐standardized peak‐use density of shorebirds was 17 times higher than at southern sites. At the community level, the system appeared stable. Annual staging averaged 5.46 million bird‐days, and neither total bird‐days, regional centroid, nor staging date changed significantly over the study period. This apparent stability, however, masked marked species‐level reorganization. Across species, 24 declined and 22 increased. Spatial and phenological shifts were not explained by breeding or wintering position, migration distance, morphology or staging population size. Instead, the trajectory of population size was the dominant correlate: declining species shifted northwards and passed earlier, whereas increasing species expanded southwards and staged later. These opposing redistributions are consistent with density‐dependent buffering across a heterogeneous staging network, whereby abundance change reshapes competitive access to higher quality sites. Stable community totals therefore concealed emerging bottlenecks for declining species, particularly at prey‐rich northern estuaries where dependence on a narrow subset of the network may intensify vulnerability to disturbance or reduced accessibility. Synthesis and applications . In heterogeneous staging networks, community stability should not be treated as evidence of conservation security. Management should move beyond static totals towards trajectory‐based prioritization: maintain southern staging capacity to accommodate expanding species while safeguarding prey availability and accessibility at key northern estuaries where declining species are concentrating. More broadly, long‐term count data can identify what to protect, where and when. Read the free Plain Language Summary for this article on the Journal blog .