Navigating coasts of concrete: Pervasive use of artificial habitats by shorebirds in the Asia-Pacific

Loss and degradation of wetlands has occurred worldwide, impacting ecosystems and contributing to the decline of waterbirds, including shorebirds that occur along the heavily developed coasts of the East Asian-Australasian Flyway (EAAF). Artificial (i.e. human-made) wetlands are pervasive in the EAAF and known to be used by shorebirds, but this phenomenon has not been systematically reviewed. We collated data and expert knowledge to understand the extent and intensity of shorebird use of coastal artificial habitats along the EAAF. We found records of 83 species, including all regularly occurring coastal migratory shorebirds, across 176 artificial sites with eight different land uses. Thirty-six species including eleven threatened species occurred in internationally important numbers. However, threatened species were less likely to occur, and larger-bodied, migratory and coastal specialist species less likely to feed, at artificial sites. Abundance, species richness and density varied across artificial habitats, with high abundance and richness but low density on salt production sites; high abundance and density on port and power production sites; and, low abundance and richness on aquaculture and agriculture. Overall, use of coastal artificial habitats by shorebirds is widespread in the flyway, warranting a concerted effort to integrate artificial habitats alongside natural wetlands into conservation frameworks. Salt production sites are cause for particular concern because they support large shorebird aggregations but are often at risk of production cessation and conversion to other land uses. Preserving and improving the condition of all remaining natural habitats and managing artificial habitats are priorities for shorebird conservation in the EAAF.