Few estimates of population density are available. Assuming average population densities of 0.25 animals per km2 in regions where it is known to be common or abundant, and 0.02 per km2 elsewhere, and with a total area of occupancy of , a total population estimate of around 28,000 is suggested. Only about 60% are in protected areas, suggesting the actual numbers of the lowland subspecies may only be in the low tens of thousands. In Kenya, their numbers have declined significantly and on
Mount Kenya, they were
extirpated within the last decade due to illegal hunting with dogs. Although information on their status in the wild is lacking, lowland bongos are not presently considered endangered. Bongos are susceptible to diseases such as
rinderpest, which almost exterminated the species during the 1890s.
Tragelaphus eurycerus may suffer from
goitre. Over the course of the disease, the
thyroid glands greatly enlarge (up to 10 x 20 cm) and may become
polycystic. Pathogenesis of goiter in the bongo may reflect a mixture of genetic predisposition coupled with environmental factors, including a period of exposure to a
goitrogen.
Leopards and
spotted hyenas are the primary natural predators (
lions are seldom encountered due to differing habitat preferences);
Central African rock pythons sometimes eat bongo calves. Humans prey on them for their
pelts, horns, and meat, with the species being a common local source for "bush meat".
Conservation In the last few decades, a rapid decline in the numbers of wild mountain bongo has occurred due to poaching and human pressure on their habitat, with local extinctions reported in
Cherang'any and
Chepalungu hills, Kenya. The Bongo Surveillance Programme, working alongside the
Kenya Wildlife Service, have recorded photos of bongos at remote salt licks in the Aberdare Forests using camera traps, and, by analyzing
DNA extracted from
dung, have confirmed the presence of bongo in Mount Kenya,
Eburru, and
Mau forests. The programme estimate as few as 140 animals left in the wild – spread across four isolated populations. Whilst captive breeding programmes can be viewed as having been successful in ensuring survival of this species in Europe and North America, the situation in the wild has been less promising. Evidence exists of bongo surviving in Kenya. However, these populations are believed to be small, fragmented, and vulnerable to extinction. Animal populations with impoverished genetic diversity are inherently less able to adapt to changes in their environments (such as climate change, disease outbreaks, habitat change, etc.). The isolation of the four remaining small bongo populations, which themselves would appear to be in decline, means a substantial amount of genetic material is lost each generation. Whilst the population remains small, the impact of transfers will be greater, so the establishment of a "metapopulation management plan" occurs concurrently with conservation initiatives to enhance
in situ population growth, and this initiative is both urgent and fundamental to the future survival of mountain bongo in the wild. The western/lowland bongo faces an ongoing population decline as
habitat destruction and hunting pressures increase with the relentless expansion of human settlement. Its long-term survival will only be assured in areas which receive active protection and management. At present, such areas comprise about 30,000 km2, and several are in countries where political stability is fragile. Therefore, a realistic possibility exists whereby its status could decline to Threatened in the near future. As the largest and most spectacular forest antelope, the western/lowland bongo is both an important flagship species for protected areas such as national parks, and a major trophy species which has been taken in increasing numbers in Central Africa by sport hunters during the 1990s. Both of these factors are strong incentives to provide effective protection and management of populations.
Trophy hunting has the potential to provide economic justification for the preservation of larger areas of bongo habitat than national parks, especially in remote regions of Central Africa, where possibilities for commercially successful tourism are very limited. to try to keep tabs on what are thought to be the last 100 eastern bongos left in the wild in the Mau Eburu Forest in central Kenya, whose numbers are still declining due to logging of their habitat and illegal poaching.
Mount Kenya Wildlife Conservancy runs a bongo rehabilitation program in collaboration with the Kenya Wildlife Service. The Conservancy aims to prevent extinction of the bongo through breeding and release back into the wild. ==Status==