Sites - Important Bird and Biodiversity Areas (IBAs)
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West Usambara Mountains
38o 17.04' East 4o 43.14' South
A1, A2, A3
800 - 2,290m
Year of IBA assessment
Site description The West Usambaras are a steep-sided block, oriented from south-east to north-west and rising from the edge of the coastal lowlands and central plateau at around 400–800 m. They have one main internal drainage system via the Umba river which flows eastwards from the north-eastern edge of the mountains. To the north lies Mkomazi Game Reserve (TZ016), to the north-west the Pare mountains, to the south-east the East Usambara (TZ070) and to the south the Pangani river valley which separates the mountains from the dry Acacia–Commiphora scrub of the Masai steppe.The western scarp is characterized by impressive sheer cliffs, often with remnant forest along the rim and extending down the many stream-eroded valleys into drier woodland at the base of the hills. The plateau has been extensively cultivated, especially around Lushoto, the district capital. Cultivation has increased significantly during the last few decades, especially noticeable in marginal land and along river valleys. The remaining forest is fragmented into many small blocks with only two large tracts remaining, both of which are under considerable pressure.The Forest Division list 27 Forest Reserves for Lushoto District. However, many of these are very small and others are production forests. Those that are significant, or are thought to be so, are Shagayu (6,223 ha protected), Shume Magamba (11,567 ha protected), Balangai West (1,074 ha), Kisimagonja (1,440 ha, badly degraded), Mjusu (3,670 ha, badly degraded), Ndelemai (3,554 ha), Bombo West (3,565 ha), Bumba Mavumbi (1,056 ha), Lutindi (2,176 ha), Mafi Hill (2,671 ha) and Ndolwa (1,173 ha). Only for Shagayu, Shume Magamba and Mafi is there anything like a complete bird inventory.In addition, there are two privately-owned forests of major ornithological importance, and are included in the IBA: Ambangulu Tea Estate, which is virtually all that remains of the lower altitude forest; and Mazumbai, which is upper montane forest.
Key Biodiversity See Box and Tables 2 and 3 for key species. The forests of the West Usambara have been far less studied for birds than those on the East Usambara mountains, especially recently. Apus barbatus breed in rock overhangs within Shume-Magambo Forest Reserve and the near-endemic Caprimulgus poliocephalus guttifer is locally common in forest-edge habitat. The rare Cinnyricinclus sharpii is often seen in the canopy at Magambo.
Non-bird biodiversity: In common with other Eastern Arc forests, the West Usambaras have a diverse fauna and flora, including a number of the Eastern Arc endemics. However, most large mammals have been extirpated. Even forest primates seem much less common than in nearby forests, suggesting a long history of over-exploitation.