Succession of benthic assemblages in Wild Bird Park, a sanctuary established on reclaimed land in Osaka Port

In order to obtain data relevant to increasing the numbers of prey organisms for shorebirds, the population of benthic animals and the environment were surveyed from 1982 to 1989 in three areas (Marsh A, Marsh B and Lagoon) of Wild Bird Park, which was laid out on reclaimed land in Osaka Port. In Marsh A, formed by standing rainwater, marine benthic organisms intruded as seawater was introduced. In Marsh B, created by the pumping in of seawater, intertidal gammarids disappeared and chironomid larvae dominated as freshwater gradually replaced the seawater. In the Lagoon, connected to the sea by ducts, a large biomass and high species diversity were found but large, intertidal animals were scarce. A comparison with the results of surveys made on the tidal flat at the mouth of Onosato River suggests that natural features should be introduced into Wild Bird Park for the future development of an intertidal assemblage.