The Establishment of Macrobenthic Faunal Communities in Planted Mangroves of Increasing Age

Abstract: The mangrove ecosystem is a tropical coastal community inhabited by organisms adapted to the stressful environment of the tidal zone. Mangrove ecosystems has in recent years been noted for the important ecosystem services they offer. Still, they are threatened by anthropogenic activities and it has been estimated that a third of the world’s natural mangrove cover has already been lost. Efforts have been made to conserve and to introduce new mangrove areas in many countries. The macrobenthic faunal community structure in the mangrove forest has a close association to environmental factors such as the age of the mangrove stand. It may therefore be used as an indicator of environmental quality. For this study, I sampled and identified macrobenthic fauna in planted mangroves of ages 18, 31 and 54 years, as well as a bare mudflat site in the Jiulongjiang Estuary, Fujian Province China. The sampled organisms were used to investigate the establishment and potential increase of diversity in macrobenthic faunal communities as a planted mangrove area develops with age. In total, 1871 individuals from 52 taxa belonging to 7 phyla were found, Crustacea and Polychaeta being the two most dominant groups. The species richness increased with mangrove age, and a linear regression on the Shannon-diversity based on biomass also showed a significant increase (p=0.0135, R2=0.6059), while the Shannon-diversity based on abundance did not. Only the 54-year old mangrove showed any significant difference to the mudflat site, and only in terms of a higher abundance (p=0.0016) and barely in a higher Shannon-diversity based on biomass (p=0.0509). The few replicates and sampled sites are probable explanations for the non-significant results. Future studies should increase the number of replicates, be conducted over several seasons, and include other physical parameters in the analysis, to get a better overview and comprehension of the macrobenthic faunal community.