South Africa: Elephants inside an invisible cage

by Jan 20, 2011Elephants

The grass is not always greener on the other side of the fence – even when the boundary fence has been broken down to give elephants more room to roam.

In fact, some elephants go out of their way to avoid fences because of their association with painful electric shocks, poachers and other human dangers.

These are some of the recent findings of elephant researchers at the University of KwaZulu-Natal (UKZN) who have been examining a wide range of behaviour and ecological impacts caused by the fences which separate humans and animals at wildlife parks around the country.

Game-proof fences have been used in South Africa for over a century to protect wildlife and to prevent conflict between animals and humans. Yet these unnatural barriers to movement have also been blamed for a variety of other problems.

The researchers are led by Professor Rob Slotow, deputy vice-chancellor of UKZN, who also directs the Amarula Elephant Research Project.

In one of the studies in the Pilanesberg National Park in North West, researchers found that the daily movement patterns of elephants were strongly influenced by the proximity of the boundary fence.

Writing in the international journal, Biological Conservation, UKZN post doctoral student Abi Vanak concluded that elephants at Pilanesberg tend to remain in the central area of the park and appear to avoid the electrified boundary fence – in some cases, by as much as 3,8km.

Over a period of three years, Vanak and his co-researchers tracked the daily movements of six elephant breeding herds using GPS collars and computer mapping.

They found that the fence-avoidance patterns were not likely to have been influenced by the availability of food, since there were no significant differences in natural vegetation when comparing the interior to the boundary area.

Though the elephants did move closer to the fence in the wet season, when more water and food was available throughout the reserve, there was still strong evidence that they tended to avoid areas close to the boundary fence.

Part of the rationale of the study was to determine whether this fence-avoidance behaviour could alter the structure of the vegetation and ecology in smaller game reserves if the elephants selectively feed in one part of the park, while avoiding the fence line.

Similar behaviour was also found in a separate elephant study in the Phinda-Munyawana private game reserve in KZN where orphan elephants and a handful of adults from Kruger National Park were re-introduced in the early 1990s.

In 2004, the size of the reserve was increased by almost 25 percent when Phinda linked up with two neighbouring reserves to create the Munyawana Conservancy. This provided an opportunity for Slotow, Heleen Druce and Kevin Pretorius to see how quickly it would take resident elephant herds to colonise the newly acquired territory.

Surprisingly, some of the elephants didn’t set foot on the new land for eight months and, when they did, they snuck in only at night for a few hours.

“For some time after the boundary fence had been removed elephants (mainly female family groups) were observed to continue to respect the fence area as though the old fence was still in place and did not attempt to cross into the new area.”

One year after the old boundary fence had been removed, more than 50 percent of the Phinda elephants had not spent more than 24 continuous hours in the new property. The most noticeable exceptions were three imported bull elephants which had only arrived in Phinda shortly before the fence was removed.

Some of these bulls crossed over the line within one month, while the younger resident bulls also began to explore the new land faster than the females.

The researchers concluded that the effects of fencing were long-lived in some species and, once removed, it might take decades for them to adapt to the new area.

“This cautious behaviour has been validated by numerous studies that have shown that animals adapt their ranging and feeding behaviour to avoid unexplored areas and human-induced disturbance.”

For example, brown hyenas in some parts of Africa only became active around midnight in order to avoid potentially hostile humans. Research in Kenya also showed that elephants tended to “streak” through unfenced corridor areas to avoid human contact.

The research at Phinda-Munyawana also suggested that elephants were unlikely to move quickly to greener pastures when wildlife managers removed international boundary fences to create new trans-frontier parks with neighbouring countries such as Mozambique and Zimbabwe.

Slotow suggests that some of the cautious behaviour shown by the Pilanesberg and Phinda elephants can be explained partly by the fact that most of these elephants had been “fence-trained”.

There are now more than 80 elephant populations living in relatively small, fenced reserves. Many of these animals were held initially in small electrified bomas before they were released and had learned to associate fences with electric shocks – whereas older animals from the Kruger National Park were not fence-trained in bomas.

Slotow disagrees with some of the conclusions reached by other researchers who suggest that the financial and ecological costs of fencing far outweigh the benefits.

Researchers Graham Kerley and Matt Hayward published an article two years ago which argues that the very act of fencing is an acknowledgement that humanity is failing to co-exist successfully with the natural environment or to conserve biological diversity.

They noted that fences often cut off animal migration routes or confine animals into small areas of land which can lead to problems such as over-crowding, genetic in-breeding and damage to other plants and animals.

Kerley and Hayward have argued that, in the long term, fences may turn out to be an equal threat to the threats they aim to overcome, and that more effort should be made to ensure that fences do not remain a permanent feature of the landscape.

Slotow acknowledges several of these problems, but argues that the benefits of fencing still outweigh the costs, particularly for the many private game reserves which could not exist without fencing.

However, he argues that it may be possible to soften their impact or even create “virtual fences” because of recent technology advances.

For example, large sections of the Ithala game reserve in KZN were completely unfenced, relying instead on natural boundaries such as rivers and steep mountains. Since the early 1990s, when elephants were re-introduced to the reserve, there had been several cases where they had moved out of the reserve.

In 2005, satellite collars were fitted to the female breeding groups and, when they did wander outside the reserve, park staff chased them back using helicopters or on foot using loud noises or gunshots.

Some parts of the Isimangaliso/St Lucia Wetland Park were also unfenced when elephants were re-introduced in 2001. But, because some parts of the lake fell outside the reserve boundaries, elephants were able to escape when drought lowered the level of the lake.

More recently, the northern sections of the Mkhuze section of the park were fenced off because of a major raid by some of the elephants into a neighbouring fruit orchard and because of plans to introduce new large predator species.

He argues that if fences are needed to contain certain species, they should be designed to keep in the target species alone, but allow other smaller and less dangerous animals to move freely.

An example of such a fence was developed at Weenen Game Reserve in KZN to limit the movement of rhinos on to neighbouring public roads.

To do this, park managers erected a single, strong cable about 30cm above the ground. Rhinos did not cross this line because they cannot lift their legs very high.

In some parks it might be also be possible to create “virtual fences” by fitting GPS collars on larger, dangerous animals which would then gain greater mobility.

If they strayed outside the park or too close to the edge of buffer zones, park managers would be alerted by real-time GPS data and assess whether they needed to chase them back towards the reserve or to warn neighbouring communities.