Overview of the project

The Bintang Bolong used to have an extensive belt of mangrove forest on both sides of the river, with numerous dead stumps showing the remnants of the forest today. The extent of mangrove degradation along the Bintang Bolong is estimated to be more than 90%, and has had big impacts on the local wildlife and agriculture (Ibrahima, 2012, M’koumfida, Yaffa and Bah, 2018). One example being the protected West African manatees (Trichechus senegalensis), that have decreased in numbers after the degradation of the mangroves along the river (Dodman, Ndiaye and Sarr, 2008).

The majority of the dieback is believed to have been caused by a severe drought in the 1970s, the Sahel drought, leading to deeper tidal penetration, and higher soil and water salinity (UNEP, 2007).

The damming of the tributary in the Casamance Region on the Senegalese side is also suspected to have contributed to the dieback of the forest, creating hypersaline conditions, and susceptibility to fungal attacks (Cham, 2014).

Efforts to replant the area was started with a pilot project in 2012 at an area further down the river, and so far a significant part of the riverbed has been successfully replanted.

The planted mangrove trees are believed to be Rhizophora mangle, but with the propagules being harvested in a separate area, and local knowledge about the different mangrove species being limited, more studies will be needed to be certain about the present species at the site.

Stands of A. germinans grows in drier areas behind the planted mangroves, and several of the stands are associated with a cover of sea purslane (Sesuvium portulacastrum). A. germinans can tolerate higher soil salinity and drier conditions, with at least some trees having survived the die back along the tributary. This is clear from evidence of regeneration, as they are the only mangrove species in the area that has not been planted, and there are fossil trunks still present from the old forest.