Mangrove accretion and depletion monitoring using remote sensing application in Ramsar convention site of Tanjung Piai, Malaysia

Abstract

Monitoring mangrove accretion and depletion is crucial especially in coastal region of tropical country. Particularly where major destruction by natural disasters and water pollution occurred that caused critical changes over short period of times. In many recent study, mangrove changes pattern is mostly dependent on the satellite image processing quality measurements and applications. At which the applications are still lacking in monitoring mangrove changes in mainland of Southeast Asia especially to assess mangrove densities. This research attempts to explore the temporal changes for three types of mangrove densities which are high, medium and low for the mangrove forests in southernmost tip of mainland Eurasia, Tanjung Piai. Medium resolution SPOT-5 for years of 2008, 2011 and 2013 were used to assess the mangrove changes supported by medium resolution RapidEye image for year of 2013. Gazette and topography map were also utilized to accurately validate the area of Ramsar site for mangrove forests to be assessed. Accuracy assessment for temporal changes achieved an average kappa of 0.94 and average of 95.95 percent of accuracy value using support vector machine learning classification algorithm. Over the 5 years period, the high density of mangrove extent increased by 49.83 percent from 13.29 percent to 26.49 percent. Medium density area depleted by 45.18 percent from 6.53 percent to 3.58 percent and low density area are also depleted as much as 81.99 percent, from 26.49 percent to 4.77 percent. This research confirmed that these mangroves constitutes the Ramsar site which brings international importance of wetland area were experiencing significant changes for every 3 years and over because of its rough coastal environment as collision point of three main straits. The study recommends continual observations and conservation in the Tanjung Piai mangrove extent using SPOT-5 image to establish trends in mangrove distributions and improvements of ecosystem services for global outreach benefits.