The Nimba massif is located in the extreme south-east of the country, at the point where the international border with Côte d’Ivoire and Liberia meet, some 50 km due east of Nzérékoré. Nimba lies at the eastern end of the Guinea Highlands and rises from the almost flat surrounding plain to 1,752 m at Mont Richard-Molard, which straddles the frontier with Côte d’Ivoire and is the highest point of both countries. The Nimba massif is some 40 km long and the largest and most dramatic part of it is in Guinea. The Nimba mountains are dissected by deep, richly forested valleys with abrupt cliff-faces between plateaux, rounded hilltops, rocky peaks and bare granitic blocks. There are three major vegetation-types within the reserve; grassland, forest and wooded savanna. High-altitude grassland with Loudetia kagerensis occurs near the summit with woody plants such as Protea occidentalis on the slopes. Forest remnants at high altitude are dominated by Myrtaceae, with the tree-fern Cyathula cylindrica in ravines. At lower altitudes savanna occurs, interspersed by gallery forests (with Parinari excelsa) between 1,000 m and 1,600 m. Primary forest is located mainly on the foothills and in the valleys, with Triplochiton scleroxylon, Chlorophora regia, Morus mesozygia, Terminalia ivorensis, Lophira procera, Tarrietia utilis and Mapania spp. among the dominants. Drier, mid-altitude forests are found at the northern end, in which Piptadeniastrum africanum and Parkia bicolor are conspicuous elements. The whole area constitutes a vast water catchment; mean annual rainfall in the less wet Guinean parts is around 2,000 mm. The site is contiguous with IBAs CI003 and LR004 in Côte d’Ivoire and Liberia respectively.
See Box and Tables 2 and 3 for key species. This is the only site in the country from which Prinia leontica is known. There is relatively little information available on the birds of Guinean Monts Nimba, but the avifauna is likely to be similar to that recorded from the Liberian part of the mountain. Many more species than are currently known may therefore be expected to occur, including up to 16 species of global conservation concern.
Non-bird biodiversity: The floristic and faunistic importance of Monts Nimba is considerable. Endemic plants include the fern Asplenium schnelli and the flowering plants Blaeria nimbana, Osbeckia porteresii and Dolichos nimbaensis. More than 500 species of fauna new to science have been described from specimens collected in the Mount Nimba Reserve. Endemics include an amphibian Schoutedenella nimbaensis, known only from the type-locality in Guinea, a viviparous toad Nimbaphrynoides occidentalis (EN) and an aquatic insectivore Micropotamogale lamottei (EN). Other, non-endemic, mammals of global conservation concern include Colobus polykomos (LR/nt), Procolobus badius (LR/nt), Cercopithecus diana (VU), Pan troglodytes (EN), Hexaprotodon liberiensis (VU) and Genetta johnstoni (DD).
Pressure/threats to key biodiversity
The Nimba mountains in Guinea and Côte d’Ivoire were declared a Strict Nature Reserve in 1944. They form part of a transboundary World Heritage Site, shared with Côte d’Ivoire, that was declared in 1981, and were also created a Biosphere Reserve in 1980. The reserve in Guinea now covers an area of 12,540 ha, following the excision of 1,550 ha in the northern part in 1993 as a result of the effects of prospecting for minerals that took place in the area between 1969 and 1978 and of the potential future exploitation of the extremely rich iron-ore deposits that were found. In 1995, the Guinea government established CEGEN, the centre for the management of the Mount Nimba complex. There has probably never been any settlements on the mountains themselves, but there are 10 villages in its immediate vicinity with several thousand inhabitants, mainly growing crops. Some illegal hunting and cultivation occurs within the reserve. As a result, there has been considerable degradation of the lower, northern parts of the reserve, around the edge of which runs the road linking Nzérékoré with Danane in Côte d’Ivoire. The influx of large numbers of refuges from Liberia in the recent past has exacerbated this problem. The main threat to the site as a whole, however, is from mining; not only of those deposits on the Guinean side which have yet be exploited but also from the recommencement of massive iron-ore mining operations in the southern part of the mountains in Liberia. Here about 6,000 ha have been drastically affected by the building of roads, wells, mine-shafts, workshops and townships. In particular, the removal of hundreds of square metres of soil over large areas has led to streams throughout the area becoming polluted with heavy-metal-tainted run-off.