Roles of aboveground roots facilitating sedimentation and elevation change in a mangrove forest behind bamboo seawalls

We studied sedimentation rates and elevation changes in a naturally rehabilitated-mangrove forest dominated by Avicennia spp. and compared the results to a seedling plantation of Rhizophora mucronata and a bare soil area behind bamboo seawalls in Samutsakorn, Thailand. The average sedimentation rates in the forest plots (0.0196 g cm d) were significantly lower than those in the bare-soil plots (0.0269 g cm d) which had a greater variation in the sedimentation rates that indicated a less consistent sedimentation rate on the exposed soil surface. Consequently, the annual net elevation changes were positive in the plots with the presence of mangrove roots (ranging from 6.37-10.87 cm) compared to negative changes in the bare-soil plots (ranging from –5.97 to –12.97 cm). The results highlighted the importance of the natural mangrove forest having a higher potential to accumulate sediments and stabilize the coastal area compared to the adjacent bare soils area behind the bamboo seawall.