Grandes Chutes Classified Forest

A(i)Site contains one or more globally threatened species, B(i)Site contains a high number of species within defined habitat or vegetation types, C(iii)Site contains nationally threatened or restricted habitat or vegetation types, AND/OR habitats that have severely declined in extent nationally

This is the only known global site for four species of plant, such as Scleria guineensis, a critically endangered endemic species to Guinea and a new species to science of Coleus. Grandes Chutes falls is the only known global site for the Podostemaceae species, Inversodicraea pygmaea and several other species of Podostemaceae; they may now be extinct due to the construction of a dam for hydro-electric power. It also has a population of Raphionacme caerulea (EN). The seepage areas are rich in carnivorous plant species including the threatened species Utricularia pobeguinii (EN) and Utricularia macrocheilos (VU). The area is under threat from increased mining activities, housing and cattle grazing.

Grandes Chutes Classified Forest is located between the towns of Coyah and Kindia on the N1 national highway, in Kindia Prefecture. The area is part of the southern extent of the Fouta Djallon, with low elevation sandstone outcrops with shallow valleys and bowal. The sandstone bowal has several microhabitats, including seasonal seepage areas which support threatened herb species such as Utricularia pobeguinii, Raphionacme caerulea, and Scleria guineensis. Part of the classified forest has an active bauxite mining concession owned by RUSAL. The Grandes Chutes falls, after which the area is named, was dammed in the 1960s to provide power to the nearby town and open-cast bauxite mine. This may have resulted in the global extinctions of Inversodicraea pygmaea and Stonesia gracilis, as this was their sole global site. They have not been discovered elsewhere, despite searches.

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The classified forest is the only known site for Scleria guineensis a critically endangered (CR) endemic species to Guinea. It also has a population of Raphionacme caerulea (EN). The seepage areas are rich in carnivorous plant species including five species of Lentibulariaceae two of which are threatened (Utricularia pobeguinii (EN) and Utricularia macrocheilos (VU)). Grandes Chutes falls is the only known global site for the Podostemaceae species, Inversodicraea pygmaea and Stonesia gracilis; several other species of Podostemaceae are also recorded from the site, but due to the change in hydrology caused by the dam, they are likely extinct. Targeted searches for them in January 2018 failed to find them.

Low sandstone hills with sandstone bowal, rich in bauxite in some parts, with crevices and cracks, seepage areas and temporary waterways. Ordovician sandstone of the Pita suite with patches of aleurolites (Source: Carte des Mineraux de la Guinee, Ministry of Mines, Government of Guinea, 2006).

There are numerous threats to the Grandes Chutes Classified forest, most notable from the RUSAL mine and its potential expansion. There is a lot of dust across the area from the access roads and the mine itself coating the vegetation. The hydroelectric dam has already caused damage to the Podostemaceae populations. There is also an area that has been marked out for housing (seen from Google Earth). From recent visits to the area, cattle grazing and trampling in the seepage areas close to the road have been observed, which has also led to fires across the bowal areas.

Since the mine and hydroelectric dam are already established, the TIPA area will have two core areas of protection within the larger boundary of the CF to protect specific populations of threatened species.

Charlotte Couch, Royal Botanic Gardens Kew

Martin Cheek, Royal Botanic Gardens Kew

Denise Molmou, Herbier National de Guinee/ Simfer