Survey of the Southern Itombwe Massif

The Itombwe Forest is the largest, most diverse and, from a conservation standpoint, probably the most important of the montane forests of Africa's Albertine Rift. There are three birds which are endemic to Itombwe: the Congo bay (Itombwe) owl Phodilus prigoginei, Schouteden's swift Schoutedenapus schoutedeni, and Prigogine's nightjar Caprimulgus prigoginei. Itombwe is now ranked as the single most important forest for bird conservation on continental Africa. As of our survey, the mammal list stood at 56 species. Most notable among these are gorilla, chimpanzee, elephant, leopard, bongo and golden cat. Two endemic shrews occur.

The Survey

The main objectives of the survey were to: 1) determine the current distribution and status of Grauer's gorilla and chimpanzees in the Itombwe Massif, 2) evaluate the impact of human activities on these and other large mammal species, and 3) assess options for conservation in the region. In addition to its field teams, the expedition benefited by the participation of an IZCN (Institut Zairois pour la Conservation de la Nature) education team led by Yuma Mkeyo and Radar Birhashirwa. The education team was instrumental in establishing good working relations with local populations in the areas we worked. A "bird survey team" conducted research in the extreme south-east corner of Itombwe.

Results

A total of 252 species of birds were found during this survey. A few additonal species (owls, nightjars, crakes) will likely be identified once their tape recorded vocalizations are reviewed. Twenty-five bird species were found which were not on the Itombwe list. One species, the Congo bay owl, deserves particular mention as it is perhaps Africa's least known bird. It now appears that it is a bird of the montane forest-grassland mosaic and gallery montane forest. These are habitat types which are poorly represented in Equatorial Africa but which are widespread in Itombwe.
A total of 35 species of mammals other than primates were also recorded. Elephants were present but in very low numbers, probably as a result of considerable recent poaching. Thirteen species of primates are known to occur in Itombwe. During this survey we added three species of primates to the list (Otolemur crassicaudatus, Galago matschiei, Galago thomasi) and confirmed the presence of eight others. One additional species, l'Hoest's monkey Cercopithecus lhoesti, was reported by hunters.

Primates in the Itombwe Forest, Eastern Zaire

• Potto Perodicticus potto
• Large-eared greater galago Otolemur crassicaudatus
• Eastern needle-clawed galago Galago matschiei*
• Thomas's galago Galagoides thomasi
• Olive baboon Papio anubis tessellatus
• Grey-cheeked mangabey Cercocebus albigena johnstoni
• Red-tailed monkey Cercopithecus ascanius schmidti
• Blue monkey Cercopithecus mitis stuhlmanni
• Wolf's monkey Cercopithecus wolfi denti
• Angolan black-and-white colobus Colobus angolensis prigoginei
• Red colobus Procolobus badius foai*
• Chimpanzee Pan troglodytes schweinfurthi**
• Gorilla Gorilla gorilla graueri*

  * near-threatened; ** threatened

Gorillas are localized in Itombwe to geographically discrete areas, and are apparently absent, except possibly for dispersing animals, from large areas. Prior to our expedition, 17 "gorilla areas", ranging in size from less than 100 km² to several hundred square kilometers, were identified in the 1959 survey of George Schaller and John Emlen. The WCS/IZCN expedition was able to visit 12 of these areas. Gorillas or their signs were observed in all but four. Gorillas are likely now absent from most of the five areas which this expedition did not survey. Significantly, we were able to document the presence of two, previously unknown, "gorilla areas" in Itombwe and map a major extension to a third. At this point, we can not provide an estimate of the number of gorillas actually in Itombwe. An analysis of the data is continuing.
The highly localized distribution of gorillas in Itombwe may be linked to habitat requirements. Gorillas were found at elevations from less than 1,100 m in the transition forest zone to over 3,000 m near Lac Lungwe. Although most of the sign and sightings of gorillas were in secondary vegetation, this species was also present in agricultural fields, at the savannah border and on the edge of human settlements. We also found gorilla signs in the bamboo zone, but at low densities, suggesting that this habitat, which in Itombwe covers more area than in any other place in Africa, may not be preferred by gorillas, or perhaps is used only seasonally. Gorilla sign was notably rare or entirely absent throughout much of the primary high canopy forest.
In contrast to gorillas, chimpanzees are more widely distributed, occurring in primary forest as well as in secondary vegetation. We did not find signs of chimpanzees in the bamboo. Although we are not yet prepared to provide estimates of chimpanzee numbers for Itombwe, they are clearly more abundant than gorillas. In addition, they appear to occur in larger groups than gorillas.

Conservation: Status and Options

Despite a low human population density over much of Itombwe, the fauna is at high risk from well established and growing commercialized hunting which provides meat for markets as far off as Kamituga and Uvira. The impact of this hunting has been devastating on duikers and many primates. This is especially the case for northern Itombwe, but hunters are rapidly expanding into less heavily exploited areas in the south. We expect that similar depletion of the fauna will follow here as well. Gorillas and chimpanzees are hunted for meat by some hunters. Other hunters, however, said they do not hunt them, citing the offical protection status of these two species and/or dietary taboos. Even these hunters, however, said that both apes are occasionally killed in snares set for other animals and that some gorillas are killed because they are agressive towards humans, especially in the gardens and around villages. We were shown a number of skins and skulls of gorillas by villagers throughout the area surveyed.
Large areas of Itombwe's natural habitats do indeed remain intact, but current trends towards deforestation, exacerbated by a famine caused by corn blight in the highlands, are extremely worrying. Particularly vulnerable is the species rich montane gallery forest/alpine meadow complex, where the woodlands are under attack by the farmers and the meadows are over-grazed by Tutsi pastoralists who have made their way into this region over the last 50 years.
Creating incentives and initiatives for the conservation of Itombwe in the face of growing insecurity stemming from the civil wars in neighbouring Rwanda and Burundi will be difficult, especially since there is also growing ethnic tension between Tutsi pastoralists and Bembe farmers on the Plateau. Nevertheless, the IZCN education team reported an interest on the part of several of the Bembe chiefs to control hunting in their traditional chiefdoms. This suggests that there may be options for new approaches to conservation, such as hunting cooperatives which are jointly managed by the chiefs and conservation NGOs. In contrast to the farmers, few pastoralists expressed much interest in wildlife or forest conservation. Both Bembe and Tutsi, for different reasons, were involved in activites leading to rapid loss of natural habitats.
Ethnic strife may continue in the region. Ironically, this may cause some areas to be depopulated as people flee conflict. This could actually lower current deforestation and possibly market hunting, thus providing a window of recovery to badly overexploited land and wildlife.
The need for conservation of Itombwe's tremendous biodiversity is fast becoming critical. At this point, a full evaluation of the options and needs must await establishment of long-term projects on the ground. Much remains to be documented of the region's flora and fauna, and realistic conservation options will depend upon these findings. Equally necessary are projects which can establish appropriate educational and institutional-building capacities and put conservation into action. However, there can be no return by assessment teams to the region, or evaluation of conservation options until security returns. Recommendations at that point would depend upon the new political orientation of the region.

Thomas M. Butynski, John A. Hart and Omari Ilambu

Dr. Thomas Butynski has conducted wildlife research in Africa since 1971. From 1978 to 1993 he studied primates and worked on rain forest conservation in Uganda. Now he works for Conservation International and in addition for the IUCN/SSC Primate Specialist Group. Since 1995 he has made surveys in endangered montane forests in eastern Zaire/Democratic Republic of the Congo.
Dr. John Hart is Senior Scientist at WCS (Wildlife Conservation Society), New York, and Co-Director of CEFRECOF (Centre de Formation et de Rechereche en Conservation Forestiere) in Epulu, Zaire.
Omari Ilambu is a conservation biologist with extensive experience in wildlife surveys and habitat assessment. He led the Itombwe Forest portion of the Grauer's gorilla survey and a biological monitoring programme in Kahuzi-Biega in conjunction with WCS.

Itombwe overview

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