Assessment of the impacts of climate change on the Grand Saloum transboundary Wetland Complex (Senegal-Gambia)

Abstract

The Grand Saloum (Saloum Delta Reserve in Senegal and Niumi Park in The Gambia) is the first African Transboundary Ramsar Site Complex. Ecosystems in this complex were disrupted by a major extreme event (Storm) in 1987. This wetland complex is now subjected to significant dynamics characterised by shoreline mobility. The goal of this study is to assess the effects of climate phenomenon in the coastal Wetland Complex using multi-temporal (1990–2020) GIS analysis and a socio-economic survey. The rate of change of the coastline is obtained through the End Point Rate (EPR) index using DSAS. The vegetation dynamic was done by a supervised classification in Google Earth Engine (GEE). The socio-ecological survey data were analysed using SPSS software. The results revealed an annual average erosion rate of 2.44 m/year and an average accretion rate of 1.84 m/year. The coastal vegetation close to the shoreline showed a decrease of the mangrove area from 16.43% in 2000 to 15.17% in 2005 (1.26% of total mangrove cover). The mangrove area increased very slightly from 16.37% to 16.81% for the year 2010 to 2020 respectively (0.5% of total mangrove cover). The survey moreover revealed that loss of habitat and coastal vegetation removal was the main impacts of erosion. Limited access to the ecosystem resources and an increase in work difficulties were the main impacts due to the accretion. The main impacts caused by floods were land degradation and habitat loss. Hypersalinity led mainly to land degradation and loss of ecosystem resources. The local community adaptation measures were based on the type of shore and the distance of build-up from the coast. Mangrove reforestation, tree planting, dike rehabilitation, and capacity building were dominant strategies in sandy-muddy shores. These findings reveal the need for strengthening mitigation and adaptation strategies in order to address the impacts of the climate phenomenon in the ecosystem and local livelihood.