Examining Mangrove Loss and Fragmentation in the Southern Johor Region: A Spatio-Temporal Study

Abstract

Mangroves provide important ecosystem services; however intensive coastal developments in Southeast Asia are removing them at unprecedented rates. Singapore and Malaysia are among the most developed countries in the region, and they have experienced substantial losses of mangrove coverage over the past decades. These mangroves also undergo fragmentation in the process, resulting in numerous small patches with relatively complex morphologies. However, little information is available regarding these aspects. The creation of accurate historical baseline data on mangrove loss and fragmentation is thus important in order to understand the impacts of coastal development on mangrove survival and formulate more appropriate environment management policies. This thesis aims to build a robust spatio-temporal dataset on mangrove loss and fragmentation in Singapore and South Johor, collectively termed the Southern Johor Region. Historical maps and current satellite imagery covering 1958 to 2014 for Singapore were consulted and mangrove cover was digitized into a spatial dataset in ESRI’s ArcGIS software. Supervised classification techniques were also applied to four archived Landsat scenes from 1989 to 2013 in order to obtain information on past mangrove for Johor. In addition, various land use plans were reviewed to predict possible mangroves loss to developments in the near future. The spatial datasets were fed into two landscape fragmentation software, FRAGSTATS and PolyFrag, for the calculation of fragmentation metrics. Results indicated huge mangrove losses in the region that coincided with coastal development projects. Three main drivers of losses were also identified: 3 reservoir construction, land reclamation and land cover conversion. Fragmentation metrics revealed significant increases in fragmentation levels in Singapore within the study period; however the metrics for Johor proved to be inconclusive. This highlights the need for considering broader processes in coastal development and management.