This reserve is located on the easternmost of the mountain ranges in Sierra Leone, close to the eastern border with the Republic of Guinea. The highest point is the Sankan Biriwa massif, on which there are two peaks separated by a narrow gorge. Both peaks rise above 1,800 m, with the northernmost, at 1,850 m, being the second-highest peak in the country. This massif is the source of tributaries of two major rivers, the Sewa and the Mano. The vegetation consists of forest-savanna mosaic from 305 m to 915 m elevation, shrub-savanna on the plateau at 915–1,650 m, and montane grassland above 1,680 m. Gallery forest occurs along the river tributaries at 450–915 m and, in places, up to 1,375 m.
See Box and Tables 2 and 3 for key species. Over 200 species of bird have been recorded in the reserve, including six species of global conservation concern. One of these, Prinia leontica, has a very restricted distribution in Sierra Leone. Picathartes gymnocephalus has been recorded in the remnants of closed forest in the reserve.
Non-bird biodiversity: The following primates are known to occur: Pan troglodytes verus (EN), Procolobus badius (LR/nt), Colobus polykomus (LR/nt) and Cercocebus atys (LR/nt). Other mammals recorded at this site include Loxodonta africana cyclotis (EN) and Hexaprotodon liberensis (VU).
Pressure/threats to key biodiversity
This area was designated a Forest Reserve in 1947 and a Non-hunting Forest Reserve in 1973. The main threat comes from bush fires, which occasionally cause considerable damage to the forest-cover. Another potential long-term threat is mining, which takes place along the rivers at the southern end of the reserve. There is no management plan for the area, and no immediate development plans exist.