Situated west of Douala, Mount Cameroon is a vast volcanic dome, 45 km long by 30 km wide, with its long axis aligned south-west–north-east. It lies on the Atlantic Ocean coast from which it is separated by the road skirting its base which links the town of Limbe in the south to Idenau in the west. The volcano is still active and eruptions occur from fissures on its flanks about every 20 years (the last two being in 1982 and 1999). The western foothills near Debundsha experience the highest rainfall in the country (c.10,000 mm per year); this decreases with increasing altitude and also from west to east, down to 2,000 mm around Buea, in the rain-shadow. The lower slopes used to bear a continuum of forest from sea-level up to c.2,300 m (the upper limit of forest varying between 2,200–2,400 m), to be replaced above by montane grassland, volcanic rock and gravel, up to the peak at 4,095 m. Encroachment from agriculture or from logging (in Bambuko Forest Reserve on the north-western side) has been nibbling the lower levels of the forest in most places up to an altitude of a few hundred metres on the western and northern sides, but up to at least 1,000 m on the southern and eastern sides. Severe and repeated human-induced bush fires in the drier eastern section have brought about serious degradation or even complete destruction of the forest cover in places (as along the Bonakanda trail). The montane grassland above that also gets burnt almost totally every dry season, and is very impoverished. Most of the montane forest has a very open canopy (important trees being Schefflera mannii, Syzygium guineense bamendae, Nuxia congesta, Prunus africana) and a dense understorey of Acanthaceae shrubs. The lowland forest on the lower slopes has a very different structure, the canopy is mainly closed and the understorey more open. The richest and most intact block of forest is Etinde (c.30,000 ha) on the south-western side. Etinde is contiguous with Bambuko Forest Reserve (24,500 ha) to the north, and is also attached (by a narrow neck of forest north-east of Idenau) to Onge River Forest and Mokoko River Forest Reserve. These cover c.35,000 ha of lowland rainforest, spreading north towards Mbonge; some of this was logged in the past, but a core area in Mokoko river remains intact.
See Box and Tables 2 and 3 for key species. The avifauna is very diverse, with some 370 species recorded, including most of the montane endemics, of which two are known only from Mount Cameroon: Francolinus camerunensis and Speirops melanocephalus. The site is also the only Cameroon locality for Psalidoprocne fuliginosa, which is very common (0–3,000 m). The francolin is widespread on the south-western to south-eastern slopes (above Buea) from 850 m to the upper limit of the forest (c.2,300 m); its status on the northern slopes is unknown as the forest there remains unexplored. The Speirops is common from 1,700 m or 1,800 m to 2,400 m and has been recorded locally to 3,000 m in scrub-filled ravines. Schoutedenapus myoptilus, only discovered in 2001, is quite common (900–2,500 m). Malaconotus ‘monteiri perspicillatus’ was collected over a century ago and never found again; it is probably best considered an aberrant morph of M. gladiator (which is not uncommon from 900–1,800 m). The status of some Guineo–Congolian species is uncertain, as their inclusion is based on old specimens, some of which may have been misallocated (e.g. Dendropicos pyrrhogaster).
Non-bird biodiversity: Two shrews (Crocidura eisentrauti (CR), Sylvisorex morio (EN)) and a rodent Lophuromys roseveari are (on present evidence) endemic to the mountain; the shrews are unlikely to be endangered. Large mammals of conservation concern include Mandrillus leucophaeus (EN), Cercopithecus preussi (EN) (still locally common) and Loxodonta africana (EN), now seriously threatened. Among butterflies, Charaxes musakensis is known from nowhere else. There is a high level of plant endemism (possibly as many as 49 endemic species).
BirdLife International (2019) Important Bird Areas factsheet: Mount Cameroon and Mokoko-Onge. Downloaded from http://www.birdlife.org on 22/07/2019.