Situated at the point where the boundaries of Côte d’Ivoire, Liberia and Guinea meet, Mount Nimba is one of highest points in West Africa at 1,752 m. Only a relatively small amount of the extremely steeply sloping eastern side of Mount Nimba occurs on the Ivorian side of the border; more falls in Guinea where 13,000 ha is also protected as a strict nature reserve within boundaries exactly contiguous with those on the Ivorian side (IBA GN017). About half of the mountain is in Liberia, where it is unprotected (IBA LR004). The vegetation is of three main types; montane grassland, dominated by Loudetia kagerensis, at and immediately below the summit, which intergrades from around 1,600 m with Parinari excelsa-dominated montane forest in which epiphytes are conspicuous. P. excelsa extends down to about 700 m and is progressively replaced by lowland forest species such as Piptadeniastrum africanum, Lophira alata and Entandrophragma spp.
See Box and Tables 2 and 3 for key species. There is no comprehensive avifaunal list for Ivorian Nimba, but it may be expected to be similar, at corresponding altitudes, to that for Liberia which has been well studied. Species listed below and in Tables 2 and 3 qualified with ‘?’ have been reported in the Ivorian literature as occurring on Nimba, but it not clear whether these are based only on inferences from Liberian records—further surveys are required. Nimba, at least the Liberian sector, is a stronghold for Prinia leontica, a species with a very limited distribution in West Africa, most common at higher altitudes. It is also the only locality in the country from which some species are known, because it is the only place where montane grassland occurs. These include Mirafra africana henrici, Anthus similis bannermani, and Saxicola torquata nebularum; all these subspecies are restricted to Upper Guinea while the race of M. africana is endemic to Nimba.
Non-bird biodiversity: About 2,000 species of plant are known from Nimba of which 16 are considered strict endemics. The mammal fauna includes a number of threatened species such as Pan trogolodytes verus (EN), Piliocolobus badius (VU), Colobus polykomos (VU), Cercopithecus d. diana (VU), Micropotamogale lamottei (EN), the last of which is endemic to Nimba. The Mount Nimba viviparous toad Nectophyrnoides occidentalis (EN) is also endemic to the mountain. At least 20 species of insect are thought to be endemic to the mountain.
Pressure/threats to key biodiversity
Much of Liberian Nimba has been destroyed by industrial open-cast mining of bauxite which has resulted not only in the removal of much of the mountain itself, but also in considerable pollution and soil erosion of the surrounding area. Although this has not directly affected the Ivorian side, associated activities such as poaching (including lighting of fires to flush game) by and for mine staff certainly has, such that, for example, primate numbers have been severely reduced.