Dietary diversity of multiple shorebird species in an Asian subtropical wetland unveiled by DNA metabarcoding

The dietary spectra of 22 species of shorebirds foraging along the East Asian-Australasian Flyway, such as Calidris ferruginean (near threatened), Charadrius leschenaultii, Pluvialis squatarola, and Tringa stagnatilis, were determined, by applying DNA metabarcoding with 18S and COI markers on fecal DNA. Shorebirds that occurred in the wetland consumed a variety of food items, primarily a high abundance of malacostracans, mollusks, annelids, insects, and some arachnids. Different proportions of plants materials were also detected in many shorebird species. Our results revealed that dietary compositions of shorebird species have segregated from each other variously, but the many similar taxa we identified in their diets implicate that these populations of shorebirds could be competing at certain levels. Thus, any reductions in the abundance and diversities of their food resources would likely intensify their interspecific and intraspecific competitions, and simultaneously threaten the survival of multiple shorebird species. With these findings, conservation measures must be taken to protect and monitor the precious food resources for these energy-deprived shorebirds during their migration.