Modeling the Effects of Land Cover Modifications and Sea Level Rise on Coastal Mangrove Productivity: A Case Study of Anlo Beach Complex Wetland, Western Region, Ghana

Abstract

In this work, the underlying mechanisms in coastal wetlands were examined in relation to the long-term mangroves’ response to anthropogenic activities and sea level rise. Geographic information systems and dynamic modeling methodologies were used. The complexity of mangroves makes it difficult to assess mangrove forests in tropical coastal locations using simply passive remote sensing techniques. In order to overcome these difficulties, a unique GIS method called GEE that combines optical satellite imagery and synthetic aperture radar was introduced. The effect of tidal currents on the mangrove ecosystem was investigated using a process-based model. Three model scenarios of 100 tidal cycle each were run, with three variables consisting of no sea level rise (constant), low sea level rise (0.3 m), and extremely high sea level rise (2.5 m). The findings indicate that between 2009 and 2019, the area of the mangroves decreased by roughly 16.9%. Overall accuracy of 99.1%, 84.6%, and 98.9% were recorded for three scenarios of 2019 classification. Mangrove height and AGB show that in year 2000, height and AGB range from 2.0 to 12.7 m and 0 - 368 mg ha-1, respectively, while in 2020, height and AGB ranged from 2.0 - 6.3 m and 0 – 88 mg ha-1 respectively. The dynamic modeling results show that the relative hydro-period for the scenarios "no sea level rise (constant)”, "low sea level rise (0.3 m)" and "extremely high sea level rise (2.5 m)" was 64%, 65% and 71%, respectively