Planet Earth Online

Wild gorillas are affected by ecotourism

12 May 2010, by Sara Coelho

Ecotourism has become an important source of income for remote African communities living within the natural habitats of famous animal species. Gorilla tourism in particular has boomed with the strong market demand, providing jobs and business opportunities for local people in several African countries.

Inviting foreign tourists to enjoy the sights and sounds of natural parks has also become a strong motivation for governments to invest in conservation, while the presence of researchers, tourists and tourism infrastructure can work as a strong deterrent to poachers.

Ecotourism involves a certain amount of risk for the gorillas, which are known to be vulnerable to human diseases. Their immune system is not as hardened as ours, and the communication of something as trivial as a common cold from a human may have the potential to threaten the health of an entire family group. To protect the gorillas, authorities have previously established a minimum distance of seven meters to prevent disease transmission.

But are seven metres enough? 'Our goal and ethical obligation as primatologists and conservationists is to minimize any negative impact on the species that we study,' says Michelle Klailova, a PhD student at the University of Stirling. Klailova studied a group of gorillas settled at Bai Hokou, Central African Republic, to document their behaviour in response to human presence.

The study forms part of a long-term program at Bai Hokou, designed to monitor human impact on western lowland gorillas and identify potential negative triggers, so we can learn how to best minimize our level of disturbance.

Klailova and her research group followed one silverback male named Makumba for one year and recorded his vocalisations, daily activities and interactions with his 12 family members. She then compared these records with the size and type of the human group – which includes local trackers, scientists and often tourists – and its distance from the gorillas.

While the team respected the seven meter limit and made an effort to keep their numbers low, Klailova found that the size of research teams did have an effect on Makumba and his family. As the numbers increased, the gorillas spent less time feeding and instead engaged in unfocused, mixed behaviours.

'Distance had the largest effect,' says Klailova. Makumba was more likely to stop feeding and start monitoring human behaviour as observers moved closer to him. 'As humans move closer, he sacrifices part of his feeding time to monitor us, and this cannot be good,' she adds.

Aggressive behaviour towards humans also increased as their distance from the gorillas reduced. The gorillas begin to make soft barking noises – warning signals which, if ignored, can escalate into more aggressive actions like charges. This behaviour increased most markedly when humans strayed closer than 10 meters.

The seven-meter minimum distance is based on disease transmission risk. Now Klailova and her team recommend in their American Journal of Primatology paper, 'an increase of the minimum observation distance to 10 meters, to incorporate the psychological stressors of close human contact.'

Ideally, the distance should be over 18 meters, at which the gorillas stop reacting to humans, 'but this is not a realistic goal in dense forests, for researchers and especially for tourists, who have spent valuable time and effort to see the gorillas.'

While it is clear that humans have an effect on the gorillas, Klailova believes that it's important to put this into perspective. 'Human factors explain only 10 per cent of the overall variance in the results, which means that there are many other important, but yet undetermined, non-human factors that are affecting the gorillas behaviour,' she says.

Keywords: Africa, Biodiversity,

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