Vultures: First extinction, then rabies
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Durban - Africa is facing a vulture extinction crisis that could lead to an increase in marauding feral dogs and the spread of rabies and other diseases in people and animals.
The first continent-wide study on the decline of African vultures suggests that – as happened in Asia – the disappearance of one of nature’s most important scavenger species could lead to an increase in the spread of rabies as feral dogs fill the ecological gap left by vultures.
Unless the rapid disappearance of Africa’s vultures is arrested quickly, the continent is facing an extinction crisis similar to that of Asia, where vulture numbers crashed by 96 percent in just 10 years, largely from chemical poisoning.
The new study, by 15 scientists and vulture experts across the world, was published in the latest edition of Conservation Letters.
Lead author Dr Darcy Ogada, of the National Museums of Kenya, said that unless governments took urgent action to halt the vulture crisis there would be long-term consequences for people and the environment.
The authors, including South African researchers Andre Botha and Sonja Kruger, say vultures are arguably the most important scavenger species in nature and perform a vital service by ridding the landscape of rotting animal carcasses.
After assessing eight species of vulture in 22 African countries they found that overall, the population of these birds had declined by an average of 62 percent since 1961.
Some of these species, however, were projected to decline at a rate of 97 percent in just three generations.
The main causes of vulture deaths in Africa were found to be chemical poisoning (61 percent), traditional medicine (29 percent) and crashing into electrical power lines and pylons (nine percent).
In southern and north Africa there were also increasing threats from power lines and wind farms.
They noted that vulture populations had crashed in India and other parts of Asia two decades ago because of the increased use of Diclofenac, a veterinary anti-inflammatory drug for livestock.
The disappearance of vultures in Asia had resulted in a parallel increase in feral dogs that were also the main reservoir of diseases such as rabies.
“The growth in feral dog numbers will contribute to the risks associated with rabies transmission, both in Africa and in Asia, where it is estimated to have added $34-billion (R413bn) to health-care costs in India alone between 1993 and 2006.”
In Africa, they calculated continuing decline rates for eight species: Ruppell’s Vulture (-97%); White-headed Vulture (-96%); Egyptian Vulture and Cape Vulture (both -92%); White-backed Vulture (-90%); Hooded Vulture (-83%); Lappet-faced Vulture (-80%) and Bearded Vulture (-70%).
“What makes our results so concerning is that national parks and game reserves appear to offer these birds very little protection,” said Ogada.
“Because vultures are so mobile and can easily travel hundreds or thousands of kilometres, decline rates are worryingly high even within protected areas.”
The scientists recommend that African governments act urgently to arrest the crisis by passing stricter regulations to control lethal farm chemicals that are often used to poison carcasses aimed at killing lions, hyenas, jackals and other problem animals. Governments should also pass new measures to impose much harsher penalties on anyone found poisoning vultures accidentally and also ensure that new wind farms and electricity networks were either vulture-friendly or modified to reduce casualties.