Lying south west of Makambako in the regions of Mbeya, Rukwa and Iringa, the Southern Highlands comprise mountain ranges and volcanoes capped by forest-grassland mosaic. They include the two highest Mbeya Rangepeaks in southern Tanzania, Mtorwi at 2,961m (9,712ft) and Mt Rungwe, just one metre lower. However, unlike the Eastern Arcs and other centres of endemism, they have until now, received very little conservation attention. This despite initial surveys revealing significant biodiversity and a diverse suite of rare and restricted-range species. Over 120 animal and plant taxa are endLocation Mapemic to the area and some 2,000 species of vascular plants occur, approaching a quarter of the total flora of East Africa.
Many of the region’s unique plateaux and mountains were produced by Rift Valley faulting in the late Cretaceous. Subsequent volcanism also deposited lava and ash, especially at the northern end of the Lake Nyasa (Malawi) Trough. Whereas the Eastern Arcs derive moisture from the Indian Ocean, the Southern Highlands receive all its rainfall from November to April via convectional uplift from Lake Nyasa (Malawi). Consequently, whilst the region as a whole averages 1,500mm per annum, Kyela averages 2,900mm, the highest in Tanzania. Temperatures average 22 degrees C (max) and 10 degrees C (min), but from May to July frosts are common on higher ground with temperatures dropping to – 7 degrees C on Kitulo Plateau.
Of the twelve principal vegetation types across the region, the Afromontane and Afroalpine grasslands and forests between 1,800m (5,904Sylvaft) and 2,961m (9,712ft) are much the most important. Indeed, together with parts of northern Malawi, the forest-grassland mosaics of the Southern Highlands form the WWF-designated ecoregion AT1015, with its conservation status described as Critical / Endangered.
The mostly fire-climax montane grasslands (dominated by Andropogon spp.,Amarillus Eragrostis spp., Exotheca abyssinica, Hyparrhenia spp., Loudetia simplex, Monocymbium ceresiiforme, Pennisetum spp., Themeda triandra and Setaria spp.) are notoriously rich with a diverse and significant terrestrial orchid component. At least six species of fire-resistant Protea also occur. Grasslands have been described as the ‘true relict community of the Afromontane region’ and the Southern Highlands represents a large centre of endemism with Kitulo Plateau probably being the evolutionary focus.
Montane forests, meanwhile, are scattered across the region, but are less extensive, and as yet less well known botanically. Structure varies with altitude, aspect, drainage and disturbance. Some of the more common species include Albizia gummifera, Aningeria adolfi-friedericii, Aphloia theiformis, Apodytes dimidiata, Bersama abyssinica, Bridelia micrantha, ChrysFungiophyllum gorungosanum, Diospyros whyteana, EntandrophragmSA Orchida spp., Ficalhoa laurifolia, Garcinia buchananii, Garcinia kingaensis, Hagenia abyssinica, Ilex mitis, Macaranga kilimandscharica, Maesa lanceolata, Neoboutonia macrocalyx, Ocotea usambarensis Parinari excelsa, Podocarpus latifolius, Polyscias fulva, Prunus africana, and Trichocladus ellipticus. The bamboo, Sinarundinaria alpina is locally common.
At least 40 species of vascular plants are unique to the Southern Highlands and many more restricted to the Highlands and the nearby Nyika Plateau in Malawi. However, ranges are indistinct. The Kitulo Plateau has long been recognised as an area of immense botanical importance and has been the most studied, but other areas across the Southern Highlands harbour rich and highly localised plant communities. Whilst all areas share characteristics, there may be specific assemblages in Njombe, Kipengere, Ndumbi, Uporoto, Rungwe, Umalila, North and South Livingstones, Mbeya and Mbisi.
The avian significance of the Southern Highlands has been known for some time, and the Tanzania/Malawi mountains have been Pictusrecognised by BirdLife International as an Endemic Bird Area (No. 105). Six areas have beFisien designated as Important Bird Areas, Livingstone Mts (IBA 58); Njombe (IBA 61); Rungwe (IBA 65); Umalila (IBA 69); Kitulo (IBA 73); Ufipa (IBA 77). Six species have been designated as ‘category one’ (globally threatened). Three of these, Lesser Kestrel (Falco naumanni), Corncrake (Crex crex), and Blue Swallow (Hirundo atrocaerulea), are listed as ‘vulnerable’ and three, Pallid Harrier (Circus macrourus), Njombe Cisticola (Cisticola njombe) and Kipengere Seedeater (Serinus melanochrous) as ‘near-threatened’. Although there may be much yet to be discovered, a number of restricted-range herpetofauna do occur in the Southern Highlands. Amongst the reptiles, endemics include the Uporoto Horned Chameleon (Chameleo fuelleborni), the Ukinga Hornless Chameleon (Chameleo incornutus), the Ukinga Spiny-tailed Lizard (Cordylus ukingensis) and the Ukinga Montane Skink (Mabuya brauni). Amongst the amphibians, two frogs are restricted to Mt Rungwe (Probreviceps macrodactylus and Phrynobatrachus rungwensis), and national and regional endemics include Hyperolius pseudargus, H. minutissimus and H. pictus.
Until recently, many of the larger mammals were commonplace. Elephant (Loxodonta africana), Bohor Reedbuck (Redunca redunca), Bushbuck (Tregalophus scriptus), Eland (Taurotragus oryx), Buffalo (Syncerus caffer), AcraeaDuikers (Cephalophus spp.), Spotted Hyaena (Crocuta crocuta), Lion (Panthera leo), and Leopard (Panthera pardus) all occurred. Advancing human populations have significantly reduced the ranges of these species, although most still occur in small numbers. Amongst the primates, the isolated Red DilepisColobus (Colobus badius tephrosceles) occurs in Mbisi, and a unique race of Black and White Colobus (Colobus angolensis sharpei) thrives in forests in and around Mt Rungwe. The smaller mammals are less well known although there are some similarities with Eastern Arc fauna in Ukinga and Rungwe, and with Albertine Rift fauna in Mbisi. The invertebrate fauna is also of significance. For example, in addition to national endemics, at least 10 species of butterfly are endemic to the highlands and a further 8 sub-species are similarly restricted. Two representatives of the genus Neocoenyra are particularly significant. Neocoenyra petersi is known only from one population on Kitulo’s Matamba Ridge and N. mittoni flies only on the upper grassland slopes of Mbeya Range.
Kiwira Water catchment
It is little surprise given the magnitude of the Southern Highlands that they play a significant role in water catchment. They serve five of the twelve main drainage basins in Tanzania, namely the Nyasa (via the Ketewaka, Kiwira, Livulezi, Lufirio, Lumbila, Malisa, Mbaka, Nkiwe, Ruhuhu, Nyasa-Songwe rivers), the Ruaha, (via the Makali, Mbarali, Mlomboje, Kimani rivers) Kilombero (via the Hagafiro, Ndolela rivers), the Tanganyika (via the Kalambo, Kamyare rivers) and Rukwa (via the Kafufu, Luiche, Mtembwa, Rukwa-Songwe rivers). The catchment values of the Highlands thus influence the livelihoods of a quarter of the country’s population. Forest integrity is thus particularly important. Mt Rungwe is a key source of water for Tukuyu, as well as the rich and fertile agricultural valley of Kyela. Similarly, the inhabitants of Sumbawanga and Mbeya rely on the forests of Mbisi and Mbeya Range above them.
Natural habitats in the Southern Highlands are severely threatened by unsustainable land-use practices and resource Motoexploitation. A volcanic history has bestowed the area with rich and fertile soils and this, coupled with abundant rains, means that the region is both productive and in parts, highly populated. However, expanding human populations inevitably put pressure on local grasslands and forests, which are being rapidly cleared for intensive commercial agriculture. Declining forest cover poses serious threats to the region’s water supplies and unmanaged hunting has reduced mammalian populations. Management of natural habitat is hampered by limited financial and technical resources, as well as by a lack of outside appreciation of the area’s ecological and traditional values. Rivers are poisoned for fishing and the risks to human and ecosystem health are considerable. Although the natural grassland is fire-climax, excessive and unmanaged burning is also degrading the remaining areas of indigenous habitat.