Assessment of the Ecological Health of Mangrove Forests Along the Kakum and Pra Estuaries in Ghana

Abstract

Mangrove forests provide a variety of valuable uses and resources for inhabitants of coastal communities. This study was aimed at assessing the health of mangrove forests at the estuaries of Kakum and Pra using multi criteria approach involving social, biological, chemical and physical factors. The study was conducted from March 2017 to August 2018. Socioeconomic data were gathered from 136 respondents through field surveys in ten communities around the two estuaries while remote sensing and Geographic Information System (GIS) were used to characterize mangrove cover change between the period 2005-2017. Species inventory, structural parameters, litter production and soil analyses were estimated in four study plots of sizes 0.25 ha within each mangrove forest whereas physico-chemical parameters of estuarine water were measured in situ. It was observed that coastal inhabitants harvested fuel wood, timber (poles), crabs, periwinkles and tilapia from these mangrove forests. Mangrove area at Kakum reduced by 41.58 % while that of Pra increased by 12.54 %, from 2005 to 2017. A total of 23 and 20 plants species, including five and three true mangroves were encountered at the Kakum and Pra mangrove forests, respectively. The mangrove species had low structural developments in terms of size and height. Annual litter production rate was lower at the Kakum mangrove forest (9.60 t ha-1 y-1) than at the Pra mangrove forest (10.72 t ha-1 y-1). The estuaries and mangrove sediments were of moderate quality. On the basis of computed mangrove health indices (MHI), the overall health of the Kakum mangrove forest was bad, whereas the Pra mangrove forest was moderately healthy. There is the pressing need for stakeholders to institute stringent management measures for sustainable conservation of both forests.