THE SOUTHERN
HIGHLANDS
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The
area
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
 peaks
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
end emic 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.
Flora
Of the twelve principal vegetation types across the region, the
Afromontane and Afroalpine grasslands and forests between 1,800m
(5,904 ft)
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., 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,
Chrys ophyllum
gorungosanum, Diospyros whyteana,
Entandrophragm a
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.
Fauna
The avian significance of the Southern Highlands has been known for
some time, and the Tanzania/Malawi mountains have been
 recognised
by BirdLife International as an Endemic Bird Area (No. 105). Six areas have
be en 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),
 Duikers
(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
 Colobus
(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.
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.
Threats
Natural habitats in the Southern Highlands are severely threatened
by unsustainable land-use practices and resource
 exploitation. 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.
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