The Itombwe mountains run north–south beside the Albertine Rift to the west of the northernmost stretch of Lake Tanganyika in eastern DR Congo. Several peaks rise above 3,000 m, the highest being Mt Mohi at 3,475 m. In the east there is a sharp drop in altitude towards the Ruzizi plain and Lake Tanganyika, while westwards the altitude decreases more slowly. Montane forest (above 1,500 m) is estimated to cover about 650,000 ha, including 150,000 ha of bamboo and 50,000 ha of gallery forest. On the east side of the range montane forest is only patchy or occurs as galleries below 2,300 m, whereas on the western slopes there is, with decreasing altitude, bamboo, montane forest, a grassland zone, then further montane forest that intergrades with lowland forest between 1,800 and 1,200 m. Dominant tree species of the montane forest, where the canopy reaches around 25 m, include Parinari sp., Carapa sp., Homalium sp., Syzygium sp., Fagara aff. inaequalis, Sapium ellipticum, Ocotea michelsonii and Croton megalocarpus, while above 2,000 m the dominants include Hirtella sp., Symphonia sp., Olea hochstetteri, Chrysophyllum sp., and Ficalhoa laurifolia. The site contains the largest block of montane forest in the Albertine Rift mountains and is exceptional in Africa in having an unbroken progression from lowland to montane evergreen forest. The Itombwe mountains are difficult of access and human population densities are low in some parts. Forest is being cleared for agriculture and firewood around villages and cattle graze the high plateaus. The town of Kamituga, an important mining centre, lies just to the north-west of the montane forest area.
See Box and Tables 2 and 3 for key species. The site is the richest single forest area for birds in Africa, with 563 species recorded. The recently described Caprimulgus prigoginei is only definitely known from Itombwe. Phodilus prigoginei and Schoutedenapus schoutedeni are also known with certainty only from this site, although are probably not restricted to it. There are also records of Ardeola idea, Crex crex, Gallinago media and Glareola nordmanni. In addition, one species of the Lake Victoria Basin biome and one of the Zambezian biome have been recorded (see Tables 2 and 3).
Non-bird biodiversity: Little is known. An important population of Gorilla gorilla graueri (EN) occurs. Pan troglodytes (EN) and Loxodonta africana (EN) are also present. Two forest shrew species are known from single specimens in the Itombwe range. At least 21 amphibian taxa have been recorded from Itombwe above 1,500 m, most of limited distribution and six endemic.
BirdLife International (2019) Important Bird Areas factsheet: Itombwe Mountains. Downloaded from http://www.birdlife.org on 25/06/2019.