The influence of tidal action and reclamation activities on the home range selection of shorebirds

The Tiaozini area is an important transit point for shorebirds on the East Asian - Australasian Flyway. The area has a long history of reclamation and development due to its unique marine landform and rich mudflat resources. However, the mechanisms of tidal and reclamation influences on shorebirds remain unclear. Therefore, this study used GPS data of four shorebirds in the Tiaozini area from 2018 to 2020, using the Dynamic Brownian Bridge Motion model to identify core home ranges. We applied the Normalized Difference Water Index (NDWI) and the Canny edge detection algorithm on 11 phases of Landsat-8 OLI and 17 phases of Sentinel-2 MSI remote sensing images to detect waterlines, simulating instantaneous waterlines based on multi-temporal data. Moran's index was used to assess the impact of reclamation on shorebird home range selection. Results showed: (1) Home range selection of shorebirds varied interannually and seasonally, with total home range decreasing from 200.75 km² to 193.67 km2 (2) Waterline fluctuations remained stable from 2018 to 2020, with intertidal zones decreasing from 55.46 % in 2018 to 38.66 % in 2020, and utilization rates of 18.92 % in spring and 45.80 % in autumn; (3) The bivariate Moran's index between the intensity of reclamation and the probability of home range selection for each period was negative. The higher probability of shorebirds distribution was found in the eastern constructed wetlands, the central and eastern shallow water and reed marsh habitats. The areas with lower distribution probabilities concentrated in the industrial areas and urban residential areas in the southern part of the study area. This study provided a new perspective for exploring the mechanism of natural and human factors influencing home range selection at key nodes of important waterbird groups in migration routes and a reference for the conservation and restoration of waterbird habitats in World Heritage sites.