Macrobenthos recruitment success in a tidal flat: feeding trait dependent effects of disturbance history

Juvenile growth rate and production of the bivalves Macoma balthica and Cerastoderma edule and the polychaeteNereis diversicolor were investigated on two contrasting tidal flat sediments that represented different recovery stages following disturbance. Juvenile M. balthica and N. diversicolor grew faster and yielded a higher production in the early succession community where fresh microalgal food supply was higher and physical stress was lower in comparison with the mature community, while C. edule recruitment success did not differ between recovery stages. Growth rate responses were positively related to the consumer specific microalgal dietary requirement suggesting the roles of microalgal food availability and interference within the mature community on juvenile feeding efficiency. In addition to the enhanced growth, lower post-settlement dispersal in the more stable sediments of the early succession community also contributed substantially to the higher cohort production ofM. balthica and N. diversicolor at early recovery stages. This study emphasises that the recruitment success of tidal flat macrobenthic juveniles is both context- and trait dependent (i.e. disturbance history and feeding trait). As recruitment is the foundation upon which all subsequent interactions within the community take place, our results illustrate the important role of biotic– physical interactions that affect food supply and sediment stability to tidal flat benthic community dynamics