Factors Affecting the Distribution Patterns of Benthic Invertebrates at a Major Shorebird Staging Site in the Yellow Sea, China

The tidal flats of the Yellow Sea support benthic communities that are vitally important to migratory birds, but baseline information on benthic community structure and variability is largely lacking. We investigated spatial and temporal patterns of macrobenthic invertebrates in areas used by large numbers of shorebirds and how these patterns related to environmental factors at Yalu Jiang coastal wetland in the north Yellow Sea during boreal spring (March–May) from 2010 to 2012. At least 61 species were documented during the study. Monthly benthos sampling from 54 stations indicated that polychaetes and bivalves dominated the benthic communities, with capitellid or maldanid polychaetes dominating upper tidal flats and the bivalve Potamocorbula laevis dominating intermediate and lower tidal flats. The middle and eastern sites approximately 10 km apart showed substantial differences in benthic species abundance and distribution, with bivalves dominating in the middle but not the eastern site. The spatial distribution of benthos was correlated with both exposure time during the tidal cycle and sediment particle size. Benthic communities showed both annual and within season variation. Two of the frequent prey for migratory birds, namely ghost shrimps Nihonotrypaea japonica and young Potamocorbula laevis, were relatively common in 2010 and 2011, respectively, but not in 2012.