An international team of researchers from across Africa, Europe and North America have published the first continent-wide estimates of decline rates in African vultures. Their findings suggest that African vultures are likely to qualify as ‘Critically Endangered’ under the International Union for Conservation of Nature’s global threat criteria.
The study which was published recently in the scientific journal Conservation Letters also showed that many national parks and game reserves appear to offer little effective protection to vulture species in Africa.
Vultures play important roles, yet are endangered
Scavengers such as vultures are essential to a healthy ecosystem; without them carcasses are largely consumed by mammalian scavengers such as dogs and jackals and this can increase levels of disease transmission, with possibly dire consequences for human health.
Being long-lived, slow breeders, vultures take several years to reach maturity, and typically fledge only a single offspring every 1-2 years. Yet the study indicates that Africa’s vultures are declining at rates of between 70% and 97% over three generations; a time interval used by the International Union for Conservation of Nature (IUCN) when assessing a species’ threat status. Since six of the eight species are largely or wholly confined to Africa, and are projected to decline by at least 80% over three generations, the study suggests that they are likely to qualify as ‘Critically Endangered’ under the IUCN’s global threat criteria.
Dr Darcy Ogada of The Peregrine Fund and lead author of the study, said:
Large declines of Africa’s vultures should ring alarm bells due to their immense ecological importance. Vultures are a vital component of a healthy environment, especially in Africa, where ‘free’ ecosystem services such as disposal of carcasses and other waste products remain the norm. If we don’t take urgent steps to save these birds, and in particular to curtail wildlife poisoning, we should expect long-term consequences for the environment, as well as for humans in Africa.
What makes our results so concerning is that national parks and game reserves appear to offer these birds very little effective protection. Because vultures are so mobile and can easily travel hundreds or thousands of kilometres, decline rates were worryingly high even within protected areas.
The main threats causing the African vulture crisis
Continent-wide declines in vulture species have already been reported in four Asian vulture species. However the study’s authors highlight two important distinctions between the Asian vulture crisis and that in Africa. First, to date, the rates of decline evident in Africa have been substantially lower than in Asia, affording African governments a window of opportunity in which to head off the environmental consequences of a collapse in this functionally important group.
Second, while Asian vultures have declined largely as a result of a single factor (ingestion of the anti-inflammatory drug Diclofenac), African vultures face multiple threats. They include incidental and deliberate poisoning, the illegal trade in vulture body parts for traditional medicine, killing for bushmeat, mortality caused by power lines and wind turbines, and a reduction in habitat and the availability of food from wild game populations.
The study suggests that the greatest quantifiable threat to Africa’s vultures is poisoning, which accounted for 61% of all reported deaths. African vultures are often the unintended victims of poisoning incidents, in which carcasses are baited with highly toxic agricultural pesticides to kill livestock predators. However the study also shows that the recent rapid increase in elephant and rhino poaching throughout Africa has led to a surge in the number of vulture deaths recorded, as carcasses have been poisoned specifically to eliminate vultures, whose overhead circling might otherwise reveal the poachers’ illicit activities.
Estimated decline of the African vultures:
The study estimated rates of decline (over three generations) for the following eight vulture species:
- Bearded Vulture (Gypaetus barbatus) = -70%,
- Egyptian Vulture (Neophron percnopterus) = -92%,
- White-backed Vulture (Gyps africanus) = -90%,
- Rüppell’s Vulture (Gyps rueppellii) = -97%,
- Cape Vulture (Gyps coprotheres) = – 92%,
- Hooded Vulture (Necrosyrtes monachus) = -83%,
- Lappet-faced Vulture (Torgos tracheliotos) = -80%,
- White-headed Vulture (Trigonoceps occipitalis) = -96%.
The article is open access:
Ogada D., Shaw P., Beyers R.L., Buij R., Murn C., Thiollay J.M., Beale C.M., Holdo R.M., Pomeroy D., Baker N., Krüger S.C., Both A., Virani M.Z., Monadjem A. & Sinclair A.R.E. 2015. Another continental vulture crisis: Africa’s vultures collapsing toward extinction. Conservation Letters 9: 89-97. doi: 10.1111/conl.12182
En français voir ici: Les vautours africains diminuent de façon critique.