Long‐term changes in the distribution and core habitat use of a coastal delphinid in response to anthropogenic coastal alterations

Abstract

Abstract The influence of anthropogenic habitat loss on animal distribution and core habitat use can be particularly strong in animals with narrow habitat selectivity, such as the Indo‐Pacific humpback dolphin (Sousa chinensis), a delphinid species that specifically inhabits coastal and estuarine waters. This study measured the extent of habitat loss in the waters around Xiamen City, China, where intense environmental changes and coast utilization have occurred in the past 40 years. The extent of occurrence and the core habitat of the humpback dolphin were measured based on sighting records from censuses conducted in different years. A Landsat image series revealed a permanent 119.95 km2 loss of coastal waters to land reclamation, coastal modification and harbour construction from 1973 to 2013. The distribution of the humpback dolphin showed a significant shift from inshore to offshore waters and away from artificial shorelines. Though the extent of occurrence appears to change minimally, a significant shift in the core habitat from the original coastal habitats into mid‐channel waters was observed in the eastern Xiamen Bay. These results imply multiple consequences of anthropogenic coastal alterations for the humpback dolphin: the elimination of vital habitats, changes in habitat use preferences, and the partitioning of the social structure of the population. The need to adjust current protected area designations along with adequate measures to restore habitat quality and population connectivity, both locally and regionally, are considered.