The Tanzania-Malawi mountains EBA includes the chain of isolated mountain ranges which extends for c.1,900 km from the Taita hills and Mt Kasigau in south-east Kenya southwards to the southern highlands of Tanzania and the mountains of Malawi, the extreme north-east of Zambia and the northern half of Mozambique (to the north of the Zambezi river). The region covered by the EBA corresponds closely to the Tanganyika-Nyasa Mountain Group of Moreau-s (1966) classification, although the Ufipa plateau in south-west Tanzania is included in the EBA because two of the restricted-range species occur there. Most of the mountain ranges in the EBA rise to over 2,000 m, and the southern highlands of Tanzania reach 3,000 m.

The restricted-range species occur in a variety of Afromontane habitats, principally montane forest, which is currently estimated to cover c.5 km² in Kenya, 7,200 km² in Tanzania and 300 km² in Malawi, with no recent data available for Mozambique (L. A. Hansen and J. O. Svendsen in litt. 1993). The altitude at which montane vegetation occurs varies widely in different parts of the EBA; it is typically found above 1,500 m, but montane conditions occur as low as 900 m on the eastern and southern slopes of several of the mountain ranges in Tanzania.

Several of the restricted-range species occur in lowland forests in the foothills of the Usambara mountains; these forests are therefore included in this EBA. Three of the restricted-range species characteristic of the East African coastal forests (EBA 111) also occur in the Usambara mountains, and are therefore considered to be shared between the two EBAs. Other EBAs with close affinities to the Tanzania-Malawi mountains are the Eastern Zimbabwe mountains (EBA 104) and the Pare mountains in the Kenyan mountains (EBA 109) (see the biogeographical analysis in Stuart et al. 1993, who considered their avifauna to be closer to that of the Kenyan mountains EBA 109). The Taita hills and Mt Kasigau are included in this EBA (following Moreau 1966 but contra Stuart et al. 1993), rather than being treated as a separate EBA, because the taxonomic status of all those 'species' endemic to that area is unclear (see 'Status and habitat' and 'Distribution patterns' tables).

The genera Xenoperdix and Modulatrix are endemic to this EBA, and the monotypic endemic genus Swynnertonia is shared with the Eastern Zimbabwe mountains (EBA 104). Most of the restricted-range birds occur in montane forest, but six of these species have been recorded in lowland forest in the foothills of the Usambara mountains (Evans and Anderson 1992, 1993, Evans et al. 1994, Hipkiss et al. 1994, Watson and Perkin undated). Five species are associated with forest edge and non-forest habitats, including four with ranges centred on the higher parts of the Udzungwa mountains, southern highlands and Nyika plateau.

Many parts of the EBA are unexplored or only partially explored ornithologically, so the documented distributions of many of the restricted-range species are undoubtedly incomplete. For example, almost nothing is known of the Rubeho mountains, the Uvidunda mountains and most parts of the Udzungwa mountains and southern highlands (Stuart et al. 1993); civil war in Mozambique has prevented ornithological work there for decades, and the lowland forests in the foothills of many of the Tanzanian ranges remain unstudied (L. A. Hansen and J. O. Svendsen in litt. 1993). Recent fieldwork has led to new discoveries and major range extensions in the Usambara mountains (see above), Udzungwa mountains (Jensen and Brøgger-Jensen 1992, Dinesen et al. 1993), Nguu mountains (Seddon et al. 1996) and elsewhere.

Species which are known only from a single mountain range include Turdus helleri, Apalis fuscigularis and Zosterops silvanus in the Taita hills, Sheppardia montana in the Usambara mountains, Malaconotus alius and Nectarinia loveridgei in the Uluguru mountains, the recently described Nectarinia rufipennis (Jensen 1983) and Xenoperdix udzungwensis (Dinesen et al. 1994) in the Udzungwa mountains, and Apalis lynesi on Mt Namuli. Bubo vosseleri was previously believed to be confined to the Usambaras but has recently been found in the Ulugurus (Hunter et al. 1996). Several of the restricted-range species appear to have remarkably disjunct distributions, for example Orthotomus moreaui, which is known only from the Usambara mountains and the Njesi plateau, and Modulatrix orostruthus, known from the Usambara and the Udzungwa mountains, although in some cases this may reflect gaps in knowledge.

The main threat to the EBA is forest loss and degradation as a result of clearance for agriculture, the replacement of natural forest with plantations, and the collection of timber and firewood (Rodgers 1993). Twenty of the restricted-range species are threatened, principally the forest birds with particularly small ranges which are likely to be most vulnerable to habitat loss. More widespread threatened species which occur in the EBA are East Coast Akalat Sheppardia gunningi (classified as Vulnerable) and Spotted Ground-thrush Zoothera guttata (Endangered).

In the Taita hills, most forest has been cleared for cultivation or forested with exotic timbers, and the remaining 3 km² is under serious threat (McGuigan 1987, Beentje 1988, Collar and Stuart 1988, B. W. Finch in litt. 1993). The forest on Mt Kasigau is certain to be similarly restricted (L. A. Bennun in litt. 1994).

In the Usambara mountains, the large human population is putting increasing pressure on the land, and the forests are now highly fragmented (Collar and Stuart 1988, Newmark 1991). A current project run by the Finnish International Development Agency and the Tanzanian Forest Division aims to reconcile conservation and development in the East Usambara mountains by increasing the amount of forest in protected areas, including all lowland remnants (Hamilton and Benstead-Smith 1989, Tye 1993).

The Udzungwa mountains support 23 (62%) of the EBA's restricted-range species, more than any other section of it. Some of the most important sites are included in the Udzungwa Mountains National Park, including Mwanihana forest. However, many important areas lie outside this national park, including Ndundulu and Nyumbanitu mountains, although these are inside the West Kilombero Scarp Forest Reserve (Dinesen et al. 1993).

In the Ulugurus, the main mountain block has been partially protected by its extremely inhospitable terrain, but forest only covers c.120 km² and the lower slopes are being steadily cleared as a result of increasing human population pressures. The forests here are included in catchment forest reserves, and the best-quality forests are in the Uluguru North Forest Reserve (Stuart and Jensen 1985, N. D. Burgess in litt. 1993). Important forests are also found on the Nguru and Ukaguru mountains, which are not currently considered to be threatened because of their precipitous terrain and low human population, and the southern highlands, where the threats to the forest patches are unknown (see Collar and Stuart 1988).

Much of Nyika plateau is included within a national park, with sections in both Malawi and Zambia, which contains some of the area's finest Afromontane forest remnants; however, fire is a problem in the eastern foothills (Dowsett-Lemaire 1989). Most of the surviving forests in south-east Malawi lie within forest reserves, but increasing human population has posed a serious threat to the survival of mid-altitude forest; for example, over 15 km² has been lost to agricultural encroachment on the slopes of Mt Mulanje and 5 km² around Mt Thyolo, and felling for firewood is damaging montane forests near Blantyre (Dowsett-Lemaire 1989). There is no information on the status of the forest on Mt Chiperone and Mt Namuli in Mozambique (Collar and Stuart 1988).

Recommended citation
BirdLife International (2024) Endemic Bird Area factsheet: Tanzania - Malawi mountains. Downloaded from https://datazone.birdlife.org/eba/factsheet/101 on 22/11/2024.