Response of shorebird habitat selection to coastal reclamation and urbanization in an extensively developed delta: A case study in Macao, China

Abstract

Land-claim and human disturbance are major threats to shorebird population declines along the East Asian–Australasian Flyway. When existing tidal flats undergo greater anthropogenic disturbance from intensive urbanization, newly-formed tidal flats may provide alternative habitats for shorebirds. Knowledge of the key habitat factor influencing shorebirds communities is essential for tidal flat restoration and management, especially on intensively urbanized coasts. We compared the differences between old and newly-formed tidal flats in terms of habitat characteristics and shorebird communities, analyzed the influence of habitat metrics on shorebird species abundance and feeding strategies in Macao, China, from 2006 to 2009. Habitat characteristics and shorebird communities were significantly different between old and newly-formed tidal flats which represented different urbanization level. The greatest difference of shorebird communities between two tideland types occurred in winter. Artificial shoreline rather than high rise buildings had direct and negative impact on shorebird communities. The habitat factors relieved shorebirds from surrounding urbanized environment were vegetation coverage within tidal flat and adjacent grassland areas. Under the pressure of rapid urbanization, the newly-formed tidal flat, which had more natural boundaries, adequate vegetation coverage and extensive adjacent undisturbed grassland, provided more suitable habitat than old tidal flats for shorebirds in Macao. Conservation efforts for shorebirds should primary focus on maintaining the extent of current tidal flats, with emphasized management on reducing anthropogenic disturbance around tidal flats.