Dual stable isotope signatures (δ 13C and δ 15N) were applied to determine the contribution of mangrove materials and other organic carbon sources to the invertebrate community in an ecologically important mangrove ecosystem of Vietnam. We have analyzed 181 specimens of 30 invertebrate species and found δ 13C and δ 15N ranging from -14.5 to -26.8‰ and from 1.3 to 12.1‰, respectively. From taxa measured for stable isotopes, polychaete, gastropods, bivalves, and grapsid crabs living in mangrove forest showed relative low δ 13C values, while fiddler crabs inhabiting in the land-water ecotone showed the highest δ 13C values. The δ 13C showed that just a few mangrove inhabitants directly relied on the mangrove materials. The wide ranges of δ 13C and δ 15N signatures indicated that the invertebrates utilized heterogeneous diets, comprising benthic microalgae, marine phytoplankton, particulate organic matter, sediment organic matter, mangrove detritus, and meiofauna and rotten animal tissues as the supplemental nutrient food sources. Moreover, the significant correlation between δ 13C values and body sizes of invertebrates showed that snails Littoraria melanostoma and Terebralia sulcata, bivalve Glauconome virens, and portunid crab Scylla serrata exhibited ontogenetic shifts in diets. The present study showed that adjacent habitats such as tidal flat and mangrove creeks seem to contribute an important microalgal food resource for invertebrates and highlighted the need for conservations of mangrove forests and the adjacent habitats.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Aquatic Science