Like the original African primate action plan, this plan formulates conservation project priorities in part by identifying different regional primate communities and then suggesting at least one project in each community. Special attention is given to the lowland rain-forest zone, which has the highest primate species richness as well as several distinct regional communities. Other areas with special forest types and/or distinct primates are also given attention, such as the montane and coastal forests of East Africa, the mountains of Ethiopia and North Africa, and the forests and woodlands of the Casamance.
Most of the primates in the African dry forest and savanna zone have wide geographical distributions, within which are many national parks and other reserves providing reasonably good protection to primate populations. With few exceptions, the African savanna primates do not appear to be especially threatened at present (in fact they are regarded as vermin in many countries).
Many of the African rain-forest primates, on the other hand, are ecological specialists occurring at low population densities, and they live in habitats that are increasingly threatened by human activities. This plan, like its predecessor, concentrates on rain-forest primates.
Although the African rain forest (made up of moist and wet lowland forest ecosystems) occupies a smaller area than the South American or Asian rain forests, and has a lower overall tree species richness than those areas, it supports a very diverse mammal community, including about 50 primate species. As in other parts of the tropics, the rain-forest zone is under intense pressure as a result of high rates of human population growth, and agricultural and economic development. The annual rate of human population growth in Africa for 1980–85 was estimated at 2.91%, greater than in South America (2.15%) or Asia (1.91%); disturbingly, the future growth rate is predicted to remain high (2.70% annually in 2000–2005, for instance) while rates decline further elsewhere (to 1.35% in South America and 1.39% in Asia, for the same period) (World Resources Institute 1994). At the same time, environmental conditions, inefficient techniques and a lack of capital resources are causing rates of food production in Africa to lag behind those in other tropical areas. The resulting food shortages have led to an increase in subsistence farming in many forest areas. Rates of logging are also increasing, with many new companies operating (some from parts of the world not traditionally involved in tropical Africa) and logging spreading to ever more remote areas with devastating effects for primates not only from habitat disturbance but also from hunting and other factors (Wilkie et al. 1992).
In most parts of the African rain-forest zone primates are heavily hunted. Even where pressures on forest land are not yet great, primates are often hunted for food and some populations are probably being driven to extinction while their habitat is more-or-less intact. Thus, if the diversity of the African primate fauna is to be maintained, major conservation efforts must be made in the rain-forest zone. Since flourishing primate populations are usually good indicators of the general health of a rain-forest ecosystem, successful efforts to conserve these primates will usually involve conservation of the system as a whole. In relatively undisturbed African forests where there is low hunting pressure, it is not uncommon to find 6–10 sympatric monkey species, together with 1–2 apes and 2–6 prosimians. Such species assemblages are typical of the forests along the Guinea Coast of West Africa between Sierra Leone and Nigeria, of the Cameroon and Western Equatorial regions stretching from eastern Nigeria to the Oubangui River, and of the forests of the Congo Basin1 and eastern Zaire.
Map 2. The eleven distinct regional communities of African primates in this plan. Except for desert areas, much of the remainder of the continent carries savanna vegetation with a relatively uniform community of primates that is not currently under great threat. With the exception of the Casamance and Maghreb, regions are mapped here on the basis of vegetation distributions shown by White (1983).
At least six distinct primate communities can be recognized within this broad lowland rain-forest zone, each containing several endemic species. These communities (some of which have subregions with different subspecies) may have differentiated during dry phases of the Pleistocene, when the African rain forest is believed to have retracted and fragmented. The size and location of resultant refuges is a matter of debate (see e.g., Hamilton 1988; Colyn et al. 1991). Each community is here considered separately, starting in the west. A subsequent section deals with five further primate communities which occur outside the main zone. All eleven communities are shown on Map 2.
This westernmost community extends from Sierra Leone to the Dahomey Gap, an area of dry forest and woodland extending from east of the Volta River in Ghana to the western edge of Nigeria (see Map 3). The Upper Guinea forests support 5 primate species that occur only here or in drier forest further to the west: Cercocebus atys, Cercopithecus diana, Cercopithecus petaurista, Cercopithecus campbelli and Colobus polykomos. Procolobus verus and Colobus vellerosus only occur in these forests and in those of the southern Nigeria region.
Colobus polykomos and C. vellerosus meet in the area between the Bandama and Sassandra Rivers in south-central Ivory Coast, where a hybrid population has been reported. The subspecies of most of the other monkeys change in southwestern Ivory Coast between the Cavally and Sassandra Rivers. The Upper Guinea region can therefore be considered as consisting of two major subregions in terms of its primates: West and East.
Upper Guinea West has the higher rainfall and exhibits the most faunal and floral diversity and endemism; it has been proposed that a major Pleistocene forest refuge was located in this subregion, which includes the extreme south of the Republic of Guinea as well as southern Sierra Leone, all of Liberia and the extreme southwest of Ivory Coast. Primates endemic to this western area (or to this area and the Fouta Djalon region) are Colobus polykomos, Cercocebus atys atys, Cercopithecus diana diana, C. nictitans stampflii, C. petaurista buettikoferi, C. campbelli campbelli and the Procolobus badius badius. Other endemic mammals are Jentink's duiker (Cephalophus jentinki), the banded duiker (Cephalophus zebra), and Kuhn's mongoose (Liberiictis kuhni). Hunting of primates for food by people has traditionally been intense in this region, particularly in Liberia, and many of the remaining forests are threatened by commercial logging.
The Upper Guinea East subregion is smaller and has a denser human population than Upper Guinea West. Many of the major towns of Ghana and the Ivory Coast are located in or close to this subregion. This area has several endemic primate subspecies: Cercocebus atys lunulatus, Cercopithecus diana roloway, Cercopithecus petaurista petaurista, Cercopithecus campbelli lowei and Procolobus badius waldroni.
Map 3. The Upper Guinea rain forest region (shaded) showing the location of projects listed in Chapter 4.
Adult female olive colobus (Procolobus verus) in the Tai Forest, Ivory Coast. Note the pronounced sexual swelling.
Scott McGraw
Further information on the Upper Guinea area and its primates can be found in Booth (1958), Davies (1987), Dosso et al. (1981), Dunn (1991), Galat & Galat-Luong (1985), Gartlan (1982), Kuhn (1965), Martin (1991), Oates et al. (1990), Robinson (1971, 1983) and Verschuren (1982).
The region from southern Benin east to the Cross River (Map 4) is faunally complex. Here, some elements of the Upper Guinea region that have bridged the Dahomey Gap meet members of the Cameroon region to the east. There are also several local endemics not found to the east or west, including two primate species, Cercopithecus erythrogaster and C. sclateri. C. erythrogaster occurs in southwest Nigeria and southern Benin, an area in which forests are under intense pressure from agriculture and logging, and where hunting pressure is also very severe. Cercocebus torquatus occurs in the same forests, which also still harbor precarious populations of chimpanzees and elephants. C. sclateri (once considered to be a subspecies of C. erythrotis) occurs only in southeastern Nigeria up to the Cross River, an area with a very high human population density where very little of the original forest cover remains. Cercocebus torquatus also occurs between the Niger and Cross Rivers, as do Arctocebus calabarensis, Galago alleni, Euoticus pallidus and Procolobus verus. The faunas of southeast and southwest Nigeria meet in the Niger Delta, where a distinct form of red colobus monkey was recently discovered. The form of Cercopithecus nictitans in southern Nigeria is probably a different subspecies from that found east of the Cross River. Cercopithecus mona occurs throughout this southern Nigerian region and also extends into Cameroon. For more information on south Nigerian primates see Oates (1982, 1985) and Oates et al. (1992).
Map 4. The southern Nigerian rain forest region (shaded) showing the location of projects listed in Chapter 4.
Destruction of lowland rain forest to make way for a pulpwood plantation, southern Nigeria.
John F. Oates
This region is centered on Mt. Cameroon and extends from eastern Nigeria to the Sanaga River (Map 5). It includes the 2,000 km2 island of Bioko (formerly called Fernando Po). Bioko is part of Equatorial Guinea. The 30 km wide channel between the island and the Cameroon mainland is only 60 m deep, and the island must have been linked to the mainland during the last glaciation; this makes it of considerable biogeographic interest. The Cameroon region shares many species with the Western Equatorial region south of the Sanaga River, but has a high level of faunal and floral diversity and high levels of endemism (especially at high elevation, where many species are related to forms on East African mountains). Primate species endemic to the Cameroon region are Mandrillus leucophaeus, Cercopithecus preussi, and Cercopithecus erythrotis. Species found only in the Cameroon and S. Nigerian regions are Arctocebus calabarensis, Euoticus pallidus and Cercopithecus mona. Most of the Bioko primates are regarded as endemic subspecies, including Pennant's red colobus (Procolobus badius pennantii) which is very different from the Cameroonian P. b. preussi. Bioko also has a Colobus satanas population; this species occurs in the W. Equatorial region, but is absent from western Cameroon. Cercocebus torquatus is found in the Cameroon and W. Equatorial regions and also in western Nigeria, and does not show obvious subspecific variation.
Map 5. The Cameroon rain forest region (shaded) showing the location of projects listed in Chapter 4.
Since the first version of this plan was published there have been several investigations of Bioko's formerly poorly known primates. Among other things, these surveys have found that the forests in and around the Gran Caldera de Luba, in the very wet southwest of the island, are largely intact and support quite healthy primate populations.
For further information on Cameroon and Bioko, see Butynski & Koster (1994), Eisentraut (1973), Fa (1992), Gadsby & Jenkins (1992) and Gartlan (1975).
This region comprises the forest zone of Cameroon south of the Sanaga River, Gabon, mainland Equatorial Guinea, the Congo Republic, and the far south of the Central African Republic, together with the Angolan enclave of Cabinda and the Mayombe Forest of Zaire (north of the Congo River) (Map 6). This is an important area in global terms for primate conservation, containing at least 20 species of nonhuman primate. The area has a relatively low human population density and until recently supported large areas of little-disturbed forest. This region contains the largest remaining populations of Gorilla gorilla and, probably, Pan troglodytes. Endemic primate species are Arctocebus aureus, Euoticus elegantulus, Mandrillus sphinx, Cercopithecus cephus, C. solatus and Miopithecus sp. (northern form). Among endemic subspecies is the highly endangered bouvieri form of red colobus, and one or more forms of Allen's galago.
Map 6. The Western Equatorial rain forest region (shaded) showing the location of projects listed in Chapter 4.
A male mandrill (Mandrillus sphinx). The mandrill is a forest-living relative of the savanna baboons. Like the closely-related drill of the Cameroon region to the north, the mandrill of western Equatorial Africa is heavily hunted for its meat throughout much of its range.
Noel Rowe
Further information on the primates of this region may be found in Blom et al. (1992), Carroll (1990), Charles-Dominique (1977), Fay & Agnagna (1992), Gartlan & Struhsaker (1972), Gautier & Gautier-Hion (1969), Gautier-Hion (1966), Lahm (1993), Mitani (1990), Sabater Pi & Jones (1967), Tutin & Fernandez (1984) and White (1992).
This region covers the large forested area south of the main bend of the Congo River, including the forest network which extends south of the main forest block along the numerous tributaries of the Congo (Map 7). It has a low human population density. Most of the region is within Zaire, but it also includes the northern part of Angola. The levels of specific endemism in the primate fauna are low, but several endemic subspecies occur here. In fact, several somewhat distinct primate faunas occur in the Congo Basin; for instance, the Kasai river separates one major fauna in the central basin, north of the river, from one to the south that extends into Angola.
Map 7. The Congo Basin rain forest region (shaded) showing the location of projects listed in Chapter 4.
Inundated forest along the banks of the Lomako River, Zaire. This is prime habitat for Allen's swamp monkey (Allenopithecus nigroviridis) and De Brazza's monkey (Cercopithecus neglectus).
Scott McGraw
The most notable primate endemics in the Central Basin are the bonobo or pygmy chimpanzee (Pan paniscus), and Cercopithecus dryas; this subregion is also home to Cercopithecus wolfi, the tholloni form of red colobus, and Cercopithecus ascanius whitesidei.
In the South Kasai subregion is found the southern form of talapoin monkey, as well as Cercopithecus wolfi pyrogaster, C. ascanius ascanius and C. ascanius atrinasus.
Two interesting forms of mangabey occur in the Congo Basin, Lophocebus aterrimus (sometimes considered a subspecies of L. albigena) and C. galeritus chrysogaster (sometimes considered a distinct species). The latter has a very restricted distribution in the Central Basin. The unique and poorly-known swamp monkey, Allenopithecus nigroviridis, lives along the Congo River and its tributaries, both north and south of the Kasai, and north into the Congo Republic.
Colyn (1991) has recently identified a third distinct faunal area on the eastern edge of this region, between the Lomami and Lualaba Rivers. The newly-described Procolobus badius parmentierorum is restricted to this area, along with Cercopithecus mitis heymansi and C. wolfi elegans.
For more information on this region, see Colyn (1988, 1991), Kano (1984), Kingdon (1990), Machado (1969), Schouteden (1944) and Susman & Mubalamata (1984).
The upper part of the Congo and its major tributary the Lualaba separate this region from the Congo Basin. It lies between the right bank of the Congo-Lualaba and the highlands of the western Rift Valley, extending from approximately the Elila River in the south to the Itimbiri River in the north (Map 8). The ranges of many elements of the fauna extend north and west of the Itimbiri around the northern edge of the Congo Basin (meeting the Western Equatorial Region in the vicinity of the Oubangui River), while others reach east across the western Rift Valley into Uganda, Rwanda and Burundi. The region has moderate endemism and very high species richness—with 13 sympatric diurnal primates in some places (Hart et al. 1986). A Pleistocene forest refuge is often proposed to have been located in the area, referred to as the “Central Refuge” by Kingdon (1971) and “Ituri-Maniema” by Misonne (1963). Colyn, Gautier-Hion & Verheyen (1991), on the other hand, interpret available evidence as indicating that there were several small refuges on the margins of this area, particularly along the Congo/Lualaba in the west and along the Rift in the east; the presence of several small refuges could be one explanation for high levels of species richness.
Primate species endemic to Eastern Zaire and the Western Rift region (see below) are Cercopithecus hamlyni and Cercopithecus lhoesti. Subspecies endemic to Eastern Zaire are Cercopithecus wolfi denti, Procolobus badius lulindicus, P. b. langi, Colobus angolensis cordieri and C. a. cottoni. Gorilla gorilla graueri occurs here and on the western edge of the Rift. Some other notable endemic mammals in eastern Zaire are the okapi (Okapia johnstoni), the giant genet (Genetta victoriae), and the aquatic civet (Osbornictis piscivora). Eastern Zaire still contains large areas of little-disturbed forest, including extensive patches of monodominant Gilbertiodendron forest (Hart et al., 1989).
Until recently, the primates of this region had received rather little attention, but there has been recent work by Colyn (1991), Thomas (1991), Hart & Sikubwabu (1994) and Yamigawa et al. (1992, 1993).
Map 8. The Eastern Zaire rain forest region (shaded) showing the location of projects listed in Chapter 4.
Captive I'Hoest's guenon (Cercopithecus Ihoesti) in Kinshasa, Zaire.
Scott McGraw
In addition to the lowland forest regions with distinctive primate communities, several other regions of Africa have marked endemism in their primate fauna at the specific or subspecific level. These regions are, from west to east: Casamance and Fouta Djalon, the Maghreb, the Western Rift, the Ethiopian Highlands, and Coastal East Africa.
This small region covers southern Senegal, the Gambia, Guinea-Bissau and the western part of the Republic of Guinea (Map 9). It is the home of the least abundant form of savanna baboon (the Guinea baboon, Papio papio), the temminckii form of red colobus, and some significant populations of chimpanzees and of Colobus polykomos. In the past, primates have been relatively well-protected in this part of West Africa because they are not hunted for food, but the human population is large and growing rapidly, and causing extensive conversion of woodland habitats. There were two large relatively well-protected areas in southern Senegal, the Basse Casamance National Park and the Niokolo-Koba National Park, but Basse Casamance has been closed since 1993 as a result of civil war. The Gambia has several small wildlife conservation areas. Further information is in Galat et al. (1992), McGrew et al. (1981), Moore (1985), Starin (1989) and Sugiyama & Soumah (1988).
Apart from the small feral population on Gibraltar, Macaca sylvanus is today restricted to a few isolated areas of montane forest in Morocco and Algeria: fir forest in the Rif and Djebel Babor, and cedar and oak forests in the Moyen Atlas and Djurdjura (Map 10). These forests are under increasing human exploitation pressure (see Fa 1983 and Fa et al. 1984). There are no other primates in North Africa, and all other members of the genus Macaca live in Asia.
The forests at medium and high elevations along the Western (or Albertine) Rift Valley in eastern Africa (Map 11) contain several endemic and threatened primates, including the mountain gorilla (Gorilla gorilla beringei), the tephrosceles form of red colobus, some highly localized forms of Cercopithecus mitis (kandti, doggetti and schoutedeni), Colobus angolensis ruwenzorii and C. a. prigoginei and Galago matschiei. Cercopithecus lhoesti and C. hamlyni occur in some areas, as well as in the E. Zaire region. Several forests contain important chimpanzee populations.
Map 9. The Casamance woodland region (shaded). Project 24 was a survey of the Republic of Guinea.
Among the Western Rift forests, the Kibale Forest in western Uganda, the Bwindi-Impenetrable Forest of southwestern Uganda and the Nyungwe-Kibira Forest of southwestern Rwanda and northwestern Burundi are sites of special significance for primate conservation (Struhsaker 1981; Weber 1987). They occupy altitudinal zones intermediate between the lowland forests of eastern Zaire and the montane forests of the Virunga Volcanoes. The Kibale Forest (560 km2) lies between 1,100 and 1,600 m, Bwindi-Impenetrable (330 km2) between 1,200 and 2,600 m, and the Nyungwe-Kibira Forest (1,140 km2) between 1,650 and 2,950 m. Each supports a somewhat different assemblage of primates. For instance, Kibale (see Struhsaker 1981) contains 11 species, including Galago matschiei, Cercopithecus lhoesti, chimpanzees and much of the largest remaining population of the tephrosceles form of red colobus, which is restricted to the medium-altitude forests along the eastern border of the lakes of the W. Rift Valley, from Kibale south to Sumbawanga in Tanzania. The Bwindi-Impenetrable Forest (see Butynski 1985) contains 10 species of primate, including Cercopithecus lhoesti, chimpanzees and gorillas; the exact relationship of these gorillas to other populations remains unclear.
Map 10. The Maghreb, showing the distribution of the Barbary macaque (shaded).
Nyungwe is home to 12–14 primate species, including Cercopithecus hamlyni, C. mitis kandti and a large population of Colobus angolensis ruwenzorii, a black-and-white colobus which occurs only in the Lake Kivu area, on the Ruwenzori Mountains and in relic forests (e.g., Sango Bay) on the shore of Lake Victoria on the Uganda-Tanzania border. Another subspecies with a restricted range, Cercopithecus mitis doggetti, occurs in both Nyungwe and Bwindi-Impenetrable. Kibale, Nyungwe and Bwindi support a very rich diversity of plant and animal species, contain large areas of relatively undisturbed forest, and are located in areas where primates are not heavily hunted.
The blue monkey (Cercopithecus mitis) is an abundant species in many of the high altitude forests along the Western Rift Valley in East Africa.
Russell A. Mittermeier
The Virunga Volcanoes are an important montane ecosystem on the eastern edge of the Congo Basin. They are most significant for primate conservation as the home of what may be the only population of the mountain gorilla (see Aveling & Harcourt 1984; Butynski et al. 1990; Harcourt & Curry-Lindahl 1979; Weber & Vedder 1983). The golden monkey, Cercopithecus mitis kandti, occurs only in the Virungas and in the bamboo zone of Nyungwe area.
The small Gombe National Park (32 km2), on the shores of Lake Tanganyika, has been the site of a continuous study of chimpanzee behavior since 1960 (Goodall 1986). In addition to chimpanzees, other forest primates at Gombe are the tephrosceles form of red colobus, Cercopithecus ascanius schmidti, and C. mitis doggetti.
Map 11. The Western Rift forest region (shaded) showing the location of projects listed in Chapter 4.
The Mahale Mountains (1,600 km2) on the eastern shore of Lake Tanganyika in Tanzania have been the site of chimpanzee research since 1965. The area contains a great diversity of ecosystems, from low-lying miombo woodland, through rain forest to alpine grassland and bamboo. In addition to a population of about 700 chimpanzees (the largest in Tanzania), Mahale supports a great diversity of other fauna and flora. Among the six monkey species in Mahale are Cercopithecus mitis doggetti, the tephrosceles form of red colobus and a form of Colobus angolensis that may be a new subspecies (see Nishida et al. 1981).
The Ethiopian Highlands (Map 12) are a unique high altitude massif (much of it above 3,000 m), extensively dissected by steep-sided river gorges and bisected by the Great Rift Valley. A few primates feature among a range of endemic animals in highland Ethiopia: the gelada (Theropithecus gelada), an unusual forest-dwelling form of grivet monkey (Cercopithecus aethiops djamdjamensis), and two or more subspecies of Colobus guereza. Cercopithecus neglectus and the endemic C. mitis boutourlini occur in forests in the southwestern highlands. Recent research by Carpaneto & Gippoliti (1990) suggests that there may be more diversity among Ethiopian guerezas than is recognized by their common grouping into C. g. guereza in the southwest and C. g. gallarum in the northeast. They report that in the Harenna Forest in the Bale Mountains of southern Ethiopia, east of Lake Abaya, there is not only a population of C. a. djamdjamensis, but also a population of guerezas not readily classifiable with either the guereza or gallarum subspecies. Much of the original grassland and forest of the Ethiopian Highlands has been destroyed by cultivation and tree cutting. The recent political turmoil has probably affected protected areas.
Map 12. The Ethiopian Highlands (shaded) showing the location of projects listed in Chapter 4.
For more information on Ethiopian primates, see Berhanu 1974; Dandelot & Prevost 1972; Dunbar 1977; Kingdon 1990; and Yalden et al. 1977.
The forests of Coastal East Africa (including the mountains of southeastern Tanzania) (Map 13) show high levels of faunal and floral endemism. This reflects their isolation from the main Guineo-Congolian forest block, an area with which they have had intermittent connections for millions of years. Faunal analysis suggests that these connections to the west have been both via the Tana River and Kenya Highlands in the north, and via the mountains of southern Tanzania in the south (Kingdon 1971). Isolated relics of a once more-widely spread primate fauna still exist in a narrow strip of forest along the coast of Kenya and Tanzania and on the island of Zanzibar, in the forests along the lower Tana River, and in the Tanzanian mountains. All these areas are small and under pressure; for instance, along the Kenyan coast much of the forest has been very heavily disturbed by agriculture, logging, and the development of tourist resorts. Even the areas enclosed within forest reserves are disturbed, and threatened by encroachment and conversion to plantations.
Found throughout this region are subspecies of Cercopithecus albogularis. Found in some, but not all, forests in the region are: Colobus angolensis palliatus, Procolobus badius (three subspecies), Cercocebus galeritus (two subspecies), various forms of Galago zanzibaricus, and one or other of the greater galagos (Otolemur crassicaudatus and O. garnettii). Recent research by Bearder et al. (1995) suggests the presence of several endemic dwarf galagos in southern Tanzania and northern Malawi.
Three especially important areas for primate conservation within this region are the lower Tana River, Zanzibar and the Udzungwa Mountains. On the floodplain of Kenya's lower Tana River are many isolated forest patches, most of which support one or more of the endemic subspecies Cercocebus galeritus galeritus, Procolobus badius rufomitratus and Cercopithecus albogularis albotorquatus. Despite the establishment of a National Reserve in 1976, populations of both the mangabey and the red colobus have declined, the forest has been damaged by agricultural encroachment, and the river's flood regime—crucial to the maintenance of the forests—is being altered by dams on the upper river and irrigation schemes on the lower river (see Marsh 1978, 1985; Butynski & Mwangi 1994).
The De Brazza's monkey (Cercopithecus neglectus) is widespread in riverine forests from Cameroon in the west to Ethiopia and Kenya in the east. Kenyan populations are under threat from habitat fragmentation.
Russell A. Mittermeier
Map 13. The forests of Coastal East Africa and the Udzungwa Mountains (shaded) showing the location of projects listed in Chapter 4.
Procolobus badius kirkii (often considered a full species) is found only on the island of Zanzibar (1,650 km2) off the northern coast of Tanzania. Otolemur garnettii, Galago zanzibaricus and Cercopithecus albogularis also occur on Zanzibar, which shares some other rare mammals with the coastal forests, such as Aders' red duiker Cephalophus adersi, which is also found in the Sokoke Forest of Kenya. Although the population of P. b. kirkii on Zanzibar is small (recent estimates suggest about 1,500 individuals), it appears to be stable. However, the forest habitat of kirkii is being disturbed and encroached, and occasionally individuals are shot (see Silkiluwasha 1981).
The Udzungwa Mountains form an isolated group in south-central Tanzania between the Uluguru Mountains to the north, and the southern highlands bordering Lake Malawi to the south. For a relatively small area, the Udzungwas support a very high diversity of plant and animal species, with many endemics. Here live the majority of remaining populations of Procolobus badius gordonorum (probably numbering less than 5,000 individuals) and an endemic form of crested mangabey (Cercocebus galeritus “sanjei”), as well as Colobus angolensis palliatus (see Homewood & Rodgers 1981; Rodgers & Homewood 1982).
Finally, the floodplain forest along the Jubba and Shabeelle Rivers in southern Somalia is notable for being the most northerly outlier of the East African coastal moist forest. Virtually all the forest that once occurred along the Shabeelle has been destroyed, while only about 400 ha remained along the Jubba in 1986 (Madgwick 1989; Varty 1988). The zammaranoi form of Cercopithecus albogularis is endemic to these riverine forests, where Otolemur garnettii and Galago gallarum also occur.
1Congo River and Basin are used here instead of Zaire River/Basin as geographical rather than political terms. A significant portion of the river borders the Republic of Congo, which has not renamed this major continental feature.