Spatiotemporal pattern evolution of habitat quality and scale-dependent impacts of human disturbance in the Pearl River Estuary.

Compared to terrestrial systems, marine systems are understudied due to high openness and low plasticity. The Pearl River Estuary (PRE), rich in resources and a key area for marine conservation, faces intense anthropogenic pressure. This study developed an integrated assessment framework (geometric trend & spatial analysis) to decipher the spatiotemporal pattern of habitat quality. Results reveal that habitat quality exhibits a pronounced seaward gradient, with nearshore and estuarine areas bearing the highest ecological risks. Habitat quality near estuaries is less stable, particularly along the western coast, and shows a certain risk of steady-state shifts (Hurst<0.5). More critically, the impact of human disturbances is scale-dependent: the spatial distribution of habitat quality is linearly dominated by estuary and offshore distance, while temporal change is governed by surface runoff and land-use intensity, with respective contributions of 0.119 and 0.080. The study emphasizes estuaries as priority intervention zones, providing a framework for resource management to inform conservation and enhance social-ecological resilience.