[HCG36-P02] Preliminary report on progressing influences of rapid sea-level rise corresponding to mangrove communities in the mangrove peat depositional area and near future prediction
Keywords:Sea-level rise, Mangrove peat, Surface erosion, Pohnpei Island, Oceanic island
In the Bruguiera gymnorrhiza dominant forest with few Sonneratia alba, Xylocarpus granatum and Rhizophora apiculata behind the seaward fringe Rhizophora stylosa forest about 20 m depth, roots which usually develop in the belowground have exposed on the ground surface. Average gap height between the base of B. gymnorrhiza tree and ground surface, which is considered as an index of surface erosion, reached 42.8 cm. Surface erosion was also identified at the seaward fringe of the S. alba forest, whereas R. stylosa forest lack signs of surface erosion, even though both communities are seaward fringed forests. In the R. apiculate forest situated about 300 m inland, the old prop roots have been getting buried in mangrove peat.
These evidences suggest that the influences of sea-level rise appear first in climax forests located seaward side, whose standing tree density of Rhizophora sp. sufficiently decreased, and the S. alba forest. Dieback, fallen trees and decrease of growing rate possibly appear in the communities in the near future.