Seasonal effects on recolonization of macrobenthos in defaunated sediment: A series of field experiments

A series of experiments was carried out to investigate seasonal effects on macrobenthic recolonization in defaunated sediment. Trays with defaunated sediment were deployed sub-tidally at a clean site in Hong Kong in spring, summer, autumn and winter, and five replicates were sampled each month after each deployment. Both abundance and species number in defaunated sediment varied significantly with season, with highest values found in summer and lowest values in winter. Species composition in both initial and subsequent months was highly dependant on the time when the sediment was first made available for benthic recolonization, rather than on dominant species that were presented in the natural communities. Results of this study suggest that timing of initial colonization may be more important than life history traits of benthic species, and may play a key role in determining the subsequent succession of macrobenthic communities in sub-tropical waters. It appears that initial recolonization may depend largely on the availability and ability of species to colonize the sediment and establish themselves through competition, whereas abundances of species in the ambient environment play a secondary role.