Mangrove migration due to sea level rise

Abstract

The coastal zone of Pulau Kukup is characterized by muddy substrates and is classified as a micro -tidal coast. P otential impacts of sea level rise were studied to relate the effects of tidal inundati on regime ass o ciated with accelerated SLR and mangrove migrati on fo r the next centuries. The primary objective of this research is to simulate and estimate the potential mangroves migrati on under several conditi ons of sea level rise scenari o s projected for the years 2025, 2050 and 2100. Another go al of this study is to evaluate the C oastal Vulnerability Index (CVI) and devel op the supplementary maps for the island. Vegetati on map were devel oped from WorldView-2 data within SPRING 5.2 software. The Digital Terrain Model from IFSAR data, were processed in ArcGIS 9.3 to produce the mangrove migrati on map. The CVI study showed that the northern and s outhern sectors are highly vulnerable risk to sea level rise and this accounted for 42% from Pulau Kukup shorelines. From the field survey analyses and mangrove vegetati on map, Rhizophora apiculata and Rhizophora mucronata dominates an outer part of the mangrove belts, accounting for 89% from the total sampled trees. The study concluded that, mangrove plant will t olerate to the inundati on change in o rder o f Sonneratia alba, Rhizophora mucronata, Rhizophora apiculata, Bruguiera parviflora, Brugueira cylindrica and Xylocarpus moluccensis. A series of mangrove migrati on map for 2025, 2050 and 2100 sea level rise scenari os sh ows an adjustment to tidal inundation class due to increase of seawater level. Mangroves from the l ower zones (Z2 and Z3) migrate into the higher z one (Z4) as a resp onse t o sea level rise. In the wo rst case scenari o, more than 25% of the mangrove forest will be c onverted t o the o pen water due to a 1.3 metre sea level rise. The t otal land l oss in the year 2100 was estimated at 69.75 hectare (Case study 1), 73.52 hectare (Case study 2) and 148.92 hectare (Case study 3). The worst case scenari os will p ossibly lead to the extinction of Xylocarpus moluccensis at Pulau Kukup when zone Z4 was begin to disappear from the year 2050 SLR projecti on. In c onclusi on, the findings sh owed that the mangrove migrati ons will occur if the tidal inundation were mo dified by future sea water level. It is a strategic response devel oped by mangrove species to maintain the preferable conditi on for their optimal growth and species col onisati on. This research approach can be applied t o other mangrove forest at regi onal scale to identify the p otential mangro ve resp onse in a simple way for basic information of future development and planning for scientist, engineer, researchers and decisi on makers.