The leaf litter consumption and occurrence of sesarmid crab Parasesarma plicatum (Latreille, 1803) on habitats in Can Gio mangrove forest

The experiment was conducted from September to December, 2022 to identify the consumption of Parasesarma plicatum (Latreille, 1803) on different Rhizophora apiculata leaf litter conditions (senescent: yellowish in color, decomposition: red brown and black brown color) in a 72-h experiment with 2 crab sizes. The experiment was designed with 6 treatments and 5 replicates. Each treatment used 5 crabs which were provided with 1 type of leaves as their food. The treatments included T1: 5 bigger size crab + yellowish leaf, T2: 5 bigger size crab + reddish brown leaf, T3: 5 bigger size crab + black brown leaf, T4: 5 small crabs + yellowish leaf, T5: 5 small crabs + reddish brown leaf, and T6: 5 small crabs + black brown leaf. The results showed that the consumption of black brown leaf litter of the bigger size crab was the highest in weight and significantly different from all other treatments. It also showed that Parasesarma plicatum did not like to eat yellowish leaf litter in all treatments. In addition, there was not a statistically significant difference in leaf litter consumption among smaller crab groups. The research on the occurrence of sesarmid crabs in Can Gio mangrove forest identified two suitable habitats for sesarmid crabs according to tidal elevation, mangrove type and environmental factors. The main factors affecting the occurrence of sesarmid crabs in the habitats were the coverage of shading trees and the mangrove type (Rhizophora apiculata, Ceriops decandra, Avicennia officinalis, Avicennia marina and Lumnitzera racemosa). Thus, Parasesarma plicatum could play an important role in the detrital food web in Can Gio mangrove forest.