Distinct links between climate warming, mariculture activities, and coastal benthic ecosystem change

Climate warming and mariculture activities are reshaping marine ecosystems, yet how these drivers differentially influence coastal benthic ecosystems, especially within temperate bays, remains insufficiently resolved. This study examined 30 years (1991-2020) of benthic data from a large northern temperate bay - Jiaozhou Bay - China to disentangle the links between climate warming, mariculture activities, and coastal benthic ecosystem change. The results showed that benthic α diversity trajectories varied among the ten fixed inshore/offshore sites, displaying non-monotonic relationships with mariculture activities and winter warming (peaking under moderate pressure) while declining with summer warming; β diversity displayed a non-monotonic temporal trend while declined with mariculture activities and winter warming; γ diversity displayed a significant downward temporal trend. Assemblage structure shifted significantly over space and time, with most sites following similar directional trajectories and significantly related to both stressors. Climate warming explained more than twice the variation in α diversity than mariculture activities, whereas the opposite occurred in β diversity and assemblage structure. Furthermore, among 19 taxa showing significant temporal trends, none of the species sensitive to disturbance increased in abundance. These findings offer valuable insights for understanding and predicting the distinct ecological links of climate change and anthropogenic activities to coastal ecosystems.