Bees used to protect marula trees from elephants
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They may be huge and thick-skinned but the prospect of getting stung by tiny, aggressive African honeybees is enough to keep elephants in the Greater Kruger National Park away from marula trees.
This is what researcher Robin Cook and his colleagues from Elephants Alive discovered in a pioneering project using beehives hung from branches to help preserve the important fruit-bearing trees.
Cook, who recently graduated with a Master’s degree in ecology from Wits University, says elephant impacts are “a major concern to conservation managers across our protected areas” on tall tree species such as the marula.
It’s such a source of conflict that some people, explains Elephants Alive, “would rather see elephant numbers reduced through legal and lethal killings” than have these iconic tree structures altered.
“For subsistence farmers, the loss of a crop has huge ramifications to their survival. To a land manager of a protected area dependent on tourism income, dissatisfied visitors could also mean less income down the line.”
Enter the diminutive African honey bee. It “has the potential to alleviate potential conflict by peaceful means”.
Elephants, explains Cook, have sensitive areas around their eyes and ears. “They would, therefore, feel bee stings in these regions. Furthermore, the moisture in the trunk is hypothesised to potentially attract bees in search of moisture. A bee sting in the trunk could cause breathing issues for an elephant.”
Cook explains that groundbreaking scientific work by research partner Dr Lucy King from Save the Elephants to test the efficacy of African honeybees as a deterrent mechanism, has shown elephants respond negatively to the sounds of buzzing honeybees, letting off a unique warning rumble-sound.
King has used her findings to design beehive fence lines, which consist of beehives strung together by wires around farms, which protect crop fields from crop-raiding elephants. “The design has proven to be very successful in Africa as the African honeybee is a notoriously aggressive honeybee species, attacking in large swarms when disturbed. It was this information which inspired Dr Michelle Henley of Elephants Alive to come up with the idea of using the beehives to protect particular trees from elephant impact.”
Cook’s research, conducted for Elephants Alive, ran for most of last year in the Jejane Private Nature Reserve, a recently adjoined protected area in the Kruger Park.
In the three years that the reserve has had elephants, almost a quarter of the marula trees have been wiped out. “In the Greater Kruger, it’s certainly not uncommon to find marula trees that have been bark-stripped, are missing branches, or have been pushed over,” explains Cook.
The research team used 150 marula trees in a 30-hectare site, dividing the trees into 50 beehive, 50 wire-netting, and 50 dummy beehives.
“As previous research found, single active beehives or only dummy beehives are not effective against all forms of elephant impact our designed aim was to test whether placing one active and one dummy beehive in a single tree would be effective against elephant impact, lowering the costs of maintaining two active beehives.”
After the beehives were built, they were specially designed by a bee-keeper to hang from trees. Cook and his team proceeded to hang nylon ropes from the branches of the 50 beehive trees, attaching one dummy beehive to each tree’s ropes.
“Then in an overnight effort, we transferred 50 live honeybee colonies into our active beehives and hung them on the opposite sides of the each beehive tree’s dummy beehive.”
For nine months Cook and his colleagues observed all 150 trees. “Elephants moved through the study site on numerous occasions, impacting 27 control, 14 wire-netted, and one beehive tree. The wire-netting was effective against bark-stripping, but did not stop elephants breaking branches.”
The beehives, however, appeared to be highly effective against all forms of impact. “Elephants were observed approaching beehive trees, pausing, and then moving off. Furthermore, the only beehive tree to receive elephant impact had some secondary branches broken when the dummy beehive was ripped out of the tree, potentially by an aggressive musth bull observed three days later in the study site.”
Cook’s major interest lies in human-elephant conflict and using non-lethal methods to alleviate this. The “bees in trees” project, he says, has attracted interest from various protected areas, worried about the loss of trees from the impacts of elephants.
“Protected areas who wish to replicate this project have to be prepared to invest the financial and logistical effort required to set up the hives in the trees and support bee colonies in drier conditions.”
One way to help foot the bill is honey. Elephants Alive says using bees brings the added benefit of providing honey and the insects function as important pollinators.
“As local people are trained to manufacture beehives and develop bee-keeping skills, studies such as these not only contribute towards science but also broaden local community skills and could become valuable case studies for promoting job creation while promoting ecological services and system functioning.”