Effect of Asian clam shells on aquatic fauna in an artificial ditch

Freshwater bivalves perform a range of ecological functions in both rivers and lakes. However, the effects of these functions in artificial ditches, one of the main habitats for bivalves, have not yet been examined. Among the burrowing bivalves, the shells of the Asian clam, genus Corbicula, decay slowly underwater and often dominate the bottom of natural rivers and artificial ditches. Here, a manipulative experiment was performed in a mesocosm ditch to determine the differences in the abundance and community composition of aquatic fauna in cages with and without Corbicula shells and to identify the relationship between shell size composition and fauna. Following the experiment, kick net sampling was performed to identify the fauna in the ditch. The results of the experiment indicated that macroinvertebrate species richness was higher in cages with a mix of small and large shells than in those without shells. The total number of macroinvertebrates was higher in cages with shells than in those without shells. However, both the species richness and total number of macroinvertebrates did not significantly differ among the treatments with different shell size compositions. Kick net sampling revealed macroinvertebrate fauna and the presence of a fish species in the mesocosm. These results suggested that Corbicula shells may be useful for the conservation of macroinvertebrates in artificial ditches with concrete-lined and simple structures.

Automated summary

The presence of Corbicula shells in artificial ditches can enhance macroinvertebrate diversity and abundance, which is beneficial for maintaining the ecosystem of the ditches.