Monitoring mangrove forest cover declination at Kilim Karst Geoforest Park, Langkawi from 2005 to 2017 using geospatial technology

Abstract

Mangrove forests are commonly found in the coastlines and estuaries of tropical and subtropical regions. Besides having commercial values, mangroves play major roles as coastal protection, buffer zone, and nursery grounds for various types of marine organisms. Since this forest ecosystem has face problems like degradation, there are increasing efforts to monitor and assess this ecosystem for better conservation and management. Conventional mangrove mapping and field survey requires labour intensive, expensive and takes long time to complete. However, geospatial techniques comprising of Remote Sensing (RS) and Geographical Information System (GIS) today become an alternative method that can be used to access the mangrove area, especially for the difficult area. Therefore, this study aims to use geospatial approach to monitor the mangrove area at Kilim Karst Geoforest Park (KKGP), Langkawi. Object-based image analysis (OBIA) method which is involved multi-resolution and classification steps is used to extract and delineate mangrove area from very high resolution (VHR) satellite imagery from 2005 to 2017. Both segmentation and classification processes were conducted using e-Cognition software. The mangrove area from 2005 to 2017 were assessed using overlay technique in ArcGIS software to determine and evaluate the degraded area. The overall degraded mangrove area was approximately 5.632 ha. Factors affecting the decline of the mangrove cover in this study area are also determined. As conclusion, the results indicated the applicability of geospatial technique to be used to monitor and assess mangrove extent for better management and conservation proposes.