A TECHNIQUE used by park rangers to protect rhinos is ineffective and could
even be reducing the animals鈥� fertility, say researchers who have studied rhinos
in Zimbabwe.
Rangers put radio collars on rhinos so they can monitor their movements and
reach them quickly if poachers attack. To fit a collar, the rangers must
immobilise the animal by shooting it with a tranquilliser dart. But
husband-and-wife research team Zoe Jewell and Sky Alibhai of the conservation
group Rhinowatch say this harms the animals.
Rhinos that are immobilised and then fitted with radio collars take much
longer to conceive compared with rhinos that are left alone, Jewell and Alibhai
report in a future issue of the Journal of Zoology. And the radio
collars need replacing so often they are practically useless.
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They say park rangers should rely instead on non-invasive techniques, such as
tracking footprints, to keep tabs on the animals.
The findings have angered other conservationists, who say that their
proposals are impractical and expensive.
Jewell and Alibhai followed a black rhino population at the Sinamatella
protection zone in Hwange National Park from 1994 to 1998. They found that the
more often females were immobilised, the longer it took them to conceive. 鈥淥ur
figures suggest that females immobilised at least once a year showed up to a 40
per cent reduction in fertility compared with females not immobilised or
immobilised very infrequently,鈥� says Jewell. The overall birth rate was also
lower in years with more immobilisations.
The collars themselves are also largely ineffective, the researchers claim.
鈥淐ollaring has been done for decades, but there鈥檚 been no objective assessment
of its effectiveness,鈥� says Alibhai. In a future issue of Oryx, Jewell
and Alibhai will report that every year 60 per cent of the collars worn by
rhinos in Sinamatella fall off and have to be replaced. They say that rhinos鈥�
wide necks and small heads mean the collars slip off easily. 鈥淚f you want the
collar to stay on,鈥� says Jewell, 鈥測ou have to put it on quite tightly, and that
irritates the animal.鈥�
Jewell and Alibhai suggest that immobilisation should be used as little as
possible. Working with the business management company SAS, they have developed
software that can accurately identify individual animals from scanned
photographs of their footprints. In addition, they say the skills of local
people should be employed. 鈥淭he local scouts have been brought up with the
traditional skills of tracking. We have to encourage that,鈥� says Alibhai.
But rhino conservationists say that collaring is a cost-effective way to
protect the animals from poachers. 鈥淲e have to closely monitor [the rhinos鈥橾
movements, so that if they are threatened, we can send fleets to protect them,鈥�
says Gezahegn Negussie of the World Wide Fund for Nature. He says it would be
too difficult and costly to deploy enough rangers on the ground to track the
animals. 鈥淚t could also put [the rangers鈥橾 lives in danger,鈥� he says.