Miombo Ecoregion Vision Report - Biodiversity Foundation for Africa

Miombo Ecoregion Report, page 28
are of economic significance for their caterpillars, for example the mopane worm Imbrasia belina
and many species in Katanga (Shaba).
Six areas of importance for invertebrates have been provisionally identified from within the
ecoregion: Mwinilunga–Mkushi (NW Zambia; species diversity (butterflies 66, 1 endemic),
endemism); Kazungula (NW Zimbabwe, Odonata diversity); Eastern Highveld (E Zimbabwe;
butterfly diversity (300), endemism (3 butterflies)); the Luapula River (NE Zambia; freshwater
molluscs); Sumbananga–Kigoma (E Lake Tanganyika; butterfly diversity (500), endemism); and
Madidibira–Mafindi (S Tanzania; butterfly diversity (400), endemism (5 butterflies)).
3.4 Areas of Evolutionary Significance
Various parts of the Miombo Ecoregion have been important in the past both for local vicariant
evolution and for radiation of specific groups. The Great Dyke in Zimbabwe and the Kolwezi-
Lubumbashi area of the DRC/N Zambia (Wild 1965, Brooks & Malaisse 1985) with serpentine
soils have given rise to the evolution of many endemic plants adapted to mineral-toxic soils (20–
30 and 53 species respectively), while the isolation of Lake Malawi and Lake Tanganyika has
given rise to great diversification of freshwater fish and molluscs (Marshall 2000, Dudley 2000).
There are 600–800 fish species in Lake Malawi (99% endemic) and 240 species in Lake
Tanganyika (90% endemic). These fish species flocks have evolved in the past 1–2 million years
and there is a very high degree of local variation indicating that speciation is still continuing.
The grasslands, floodplains and wetlands of the palaeo-Upper Zambezi (Barotseland, Kafue,
Bangweulu, etc.) are believed to have been closely connected during past wetter periods, and to
have covered a vast area in the north. For many biological groups, this landscape of grassland
and woodland patches on Kalahari sands appears to have been an important centre of
diversification and speciation over the last 5 million years, including for lechwe and similar
antelope, suffrutex plants and grassland birds (Cotterill 2000, Timberlake et al. 2000, Mundy
2000). Much of the speciation was caused by habitat fragmentation owing to climatic change,
and the capture of the Upper Zambezi by what is now the middle and lower Zambezi.
Barotseland is regarded as a particularly rich area for reptiles and amphibians as it is the meeting
place of the Kalahari, forest and savanna faunas.
The Muchinga escarpment in eastern Zambia has been a biogeographical boundary resulting in
speciation in primates (Papio and Cercopithecus), waterbuck, tsessebe and puku. The watershed
between the Chambeshi, Upper Luangwa and Rukwa has had a similar effect, separating
southern and East African taxa.
3.5 Areas Important for Animal Movement and Migration
Seasonal movement of vertebrates such as birds and large mammals is a characteristic feature of
parts of the Miombo Ecoregion. Many movements are related to feeding, and are driven by the
availability of food in nutrient-rich or warmer parts of the landscape (wetlands, mopane
woodland, riverine woodland) compared to deficiency in nutrient-poor areas up on the plateau or
cool areas with little insect activity. However, most of these movements do not follow a fixed
pattern and are rather opportunistic and over only moderate distances. Examples are elephants
moving across northern Botswana and western Zimbabwe, and from the Zambezi floodplains up
onto the escarpment. The only true migration of large mammals is thought to be of wildebeest
from the Liuwa Plains in western Zambia into eastern Angola.