Data from: Multiple habitat use by declining migratory birds necessitates joined-up conservation

Many species depend on multiple habitats at different points in space and time. Their effective conservation requires an understanding of how and when each habitat is used, coupled with adequate protection. Migratory shorebirds use intertidal and supratidal wetlands, both of which are affected by coastal landscape change. Yet the extent to which shorebirds use artificial supratidal habitats, particularly at highly developed stopover sites, remains poorly understood leading to potential deficiencies in habitat management. We surveyed shorebirds on their southward migration in southern Jiangsu, a critical stopover region in the East Asian-Australasian Flyway (EAAF), to measure their use of artificial supratidal habitats and assess linkages between intertidal and supratidal habitat use. To inform management, we examined how biophysical features influenced occupancy of supratidal habitats, and whether these habitats were used for roosting or foraging. We found that shorebirds at four of five sites were limited to artificial supratidal habitats at high tide for ~11–25 days per month because natural intertidal flats were completely covered by seawater. Within the supratidal landscape, at least 37 shorebirds species aggregated on artificial wetlands, and shorebirds were more abundant on larger ponds with less water cover, less vegetation, at least one unvegetated bund, and fewer built structures nearby. Artificial supratidal habitats were rarely used for foraging and rarely occupied when intertidal flats were available, underscoring the complementarity between supratidal roosting habitat and intertidal foraging habitat. Joined-up artificial supratidal management and natural intertidal habitat conservation is clearly required at our study site given the simultaneous dependence by over 35,000 migrating shorebirds on both habitats. Guided by observed patterns of habitat use, there is a clear opportunity to improve habitat condition by working with local land custodians to consider shorebird habitat requirements when managing supratidal ponds. This approach is likely applicable to shorebird sites throughout the EAAF.,Jackson et al_Multiple habitat use by declining migratory birds necessitates joined-up conservationField data comprising shorebird counts and biophysical survey variables, used in generalised linear mixed-effects models described in the manuscript. Survey month: 1 = July or August, 2 = September, 3 = October; Tide Height: tide height in cm at the highest or lowest tide point during the survey; Intertidal flats cover: 1 = seawater was against the seawall during the count, 0 = seawater did not reach the seawall during the count; Water cover: % cover of water over the surface area of the whole pond; Distance: distance to seawall measured in kilometres using Google Earth; Vegetation cover: estimated non-water surface area covered by vegetation, measured as <10%, 10-30%, 30-50%, 50-70% or >70%; Bund: number of unvegetated bunds (i.e. the bank surrounding the pond, sometimes called berms) for each pond, 1= at least one unvegetated bund, 0 = no unvegetated bunds; Structures: number of structures (telephone/electricity poles/wires, buildings and trees) within 10m of the perimeter of the pond; Size: pond size measured in hectares using Google Earth; Total Count: count of total shorebird abundance (all individuals of all species).