The habitat use and home range analysis of Dunlin (Calidris alpina) in Chongming Dongtan, China and their conservation implications

Natural coastal wetlands are important habitats for shorebirds while flooded agricultural croplands, may also be useful habitats. Shorebirds in East Asia utilize an often highly developed coastal landscape, which may be dissected by seawalls with intertidal flats on the seaward side, and aquaculture ponds and agricultural croplands on the landward side. Little is known about the value of aquaculture ponds to shorebirds. We investigated the habitat use, preference and home range of wintering Dunlin (Calidris alpina) in Chongming Dongtan, east China, through radio tracking and field observations in 2006–2007. Our results indicated that Dunlins preferred tidal flats, avoided agricultural croplands, and used aquaculture ponds in proportion to their availability. The probability of Dunlin usage of aquacultural ponds decreased with increasing size of unflooded area in the aquaculture ponds. Dunlins foraging in aquaculture ponds had lower feeding success rate than those in tidal flats. Thus, tidal flats may provide important foraging habitats for wintering Dunlins, while aquaculture ponds may provide alternative roosting and supplemental foraging habitat. Conserving the natural wetlands on tidal flats is vital for shorebird conservation in East Asia but at the same time, the aquaculture ponds also could play an important role if managed properly.