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Bees, the pet hate of elephants

11/21/16

For millions of African peasants, it is vitally important to prevent elephants from coming anywhere near their crops. Over the past few years, a whole range of non-lethal means have been invented to keep savanna elephants at bay. The results are encouraging but… this animal isn't stupid. It is necessary to continuously find new dissuasive methods, while respecting the imperatives of protecting this highly endangered species. For the first time, a team from Gembloux Agro-Bio Tech has demonstrated, in Gabon, that the effectiveness of beehives and bees as a deterrent also applies to Central Africa's forest elephants.   

Gabon is mostly known in Europe for its oil bonanza and its high development index compared with neighbouring countries. However, despite this reputation, there is another far less well-known reality that has nevertheless caused a fair amount of ink to flow in the world of nature conservation. This country is the subject of an enormous paradox, relating to one of the most prestigious emblems of its vast natural heritage and biodiversity: the elephant. Although it is an endangered species, it is causing an increasing amount of damage to crops.

Forest elephant group

Eight times bigger than Belgium with a population of scarcely 1.5 million inhabitants (i.e. seven times less than the average density in Africa!), Gabon is strewn with vast forests, many of which are officially protected (parks, reserves, etc.). The majority of its population is packed into two major urban areas (Libreville and Port-Gentil) and along the main communication routes. At first sight, we could be led to believe that, generally speaking, humans and the famous pachyderm live together in harmony. Yet, in reality, it is quite a different matter. "Throughout the country, people are becoming increasingly annoyed because of crop damage caused by elephants", explains Cédric Vermeulen, professor at Gembloux Agro-Bio Tech/University of Liège. "To the point where a growing number of despondent villagers, in forests, are abandoning their fields, and this phenomenon, reported by the local elite, is increasingly turning into something of a national debate. The paradox is all the more surprising because even though the country is still home to the biggest population of forest elephants (Loxodonta Africana cyclotis), the species is in dramatic decline. The most recent figures from scientific counts are worrying: between 2002 and 2011 alone, the forest elephant's numbers fell by 62 % in Central Africa". 

Growing exasperation

The specialist in Africa and human-wildlife interactions highlights two elements as possible explanations for this paradox. On the one hand, each party's need for mobility: elephants are capable of covering great distances, bringing them in contact with human activities that require an increasing amount of space and communication routes owing to demographic pressure. On the other hand (and there is a connection here), some of the animals living in natural areas, normally associated with peaceful conditions, are actually subject to the intense pressure of poaching. Driven by the urgent need for security and food, they are tempted to "go and see elsewhere" and, by doing so, come ever closer to crops. Often located on the borders of wildlife reserves, fields rich in a wide variety of fruit and tubers (plantains, yams, manioc, etc.) allow them to satisfy their enormous food requirements more easily than by foraging in the forest. In this sort of cost/benefit balance between and hunger and the need for security, it is – in most cases – the first imperative that prevails, despite the sporadic slaughtering of these animals by exasperated villagers.

Of course, we can't completely exclude the fact that strictly political stakes may be involved in the increased focus on this theme in the country's media and political agenda. However, the social and economic reality can't be ignored: a large chunk of the rural population, which is already deprived of various facilities (hospitals, schools, drinking water, etc.) is constantly exposed to the incursions of animals capable of compromising a need as basic as access to food. "The world of conservation is undermined by this reality", Cédric Vermeulen emphasises. "Villagers are deprived of their crops and populations are suffering. We urgently need to find effective and non-lethal solutions to deter the elephants. The country's president, Ali Bongo, apparently publicly stated that he hadn't been elected by elephants..." If we read between the lines, this message could spell dark times ahead for the Loxodonta Africana Cyclotis populations. Because it is very tempting for the political elite to propose to flush them out or apply other retaliatory measures. Effective in the short term, these aren't known to solve anything in the long term. Furthermore, they risk hastening the forest elephant populations into the impasse in which they are heading.

The cleverest will win...

In the last few years, farmers and wildlife managers alike have been endeavouring to develop "soft" deterrents, aimed at discouraging elephants in their attempts to raid crops. Erecting physical or natural barriers, installing electric fences, digging trenches, using sonic or olfactory deterrents (firing chilli-based irritants), the renewed use of traditional techniques combining the use of fire and the collective supervision of the crops, etc. All these methods, particularly in East Africa (faced with pockets of overcrowding), provide more or less encouraging results according to the methods and the precise location of their use. But there is a problem: "We're dealing with a particularly intelligent animal. Elephants learn quickly... Once they have learnt how the deterrent works, they find a solution and aren't afraid anymore". 

It is true that the workings of the human/elephant relationship are complex, in Gabon and elsewhere. And that they are impacted by another, more anthropological, development linked to the living conditions in villages in agricultural areas. "Surveillance of the cultivated plots isn't as collective as before. The presence of humans in the fields, at night, has almost disappeared in favour of a division into individual plots supervised by isolated farmers. A form of individualism has taken over the collective management of agriculture, which offered shared benefits in the past. And a more modern way of life has also established itself, even in the most far-flung forests. The peasants in Gabon are just like our mountain shepherds in Europe: life in the city (or in the valley), connected to electricity and television, is more comfortable than long nights spent protecting flocks against wolves (over here) or crops against elephants (over there)".

Insects against giants

This is where the work of Steeve Ngama comes in, a PhD student at the Laboratory of Tropical and Subtropical Forestry at Gembloux Agro-Bio Tech (ULg) for the past two years, and a researcher at the Institut de Recherches Agronomiques et Forestières du Centre National de la Recherche Scientifique et Technologique in Libreville (Gabon). Drawing inspiration from similar experiments carried out in East Africa, Steeve Ngama tested the installation of special "fences" in Gabon. These fences are actually made from beehives whose bees are believed to scare off elephants. Between November 2011 and February 2013, i.e. a period of 70 weeks, he observed the mammals' behaviour when they approached the dozen or so beehives hanging in the trees just over a metre from the ground. The two species of trees were chosen for their fruit which is particularly appreciated by the elephants: Irvingia gabonensis and Sacoglottis gabonensis. The experiment took part in the Gamba complex, which is home to two national parks (Loango and Moukalaba-Doudou, 1550 and 4500 km2 respectively) whose boundaries are frequently the subject of human/elephant conflicts owing to the high density of these mammals. The repellent species tested was Apis mellifera adansonii, the only widespread Apis type of bee in central Africa. Automatically triggered cameras were installed at a distance of 10 to 20 metres from the beehives to observe the elephants' reaction.

Elephant foret ruche nuit  

"Based on the photographic material collected (8151 photographs), we listed different types of elephant behaviour, ranging from a simple visit to the site to an attempt to approach the beehives or destroy them", Steeve Ngama explains. "We quantified these behaviours by correlating them with the presence of the bees and their activities in the hives (some were empty, acting as control hives). These activities were quantified according to the number of entrances and exits – "movements" – per minute by the bees". The results were highly instructive. "We first observed that the presence of fruit on the trees is indeed a powerful factor of attraction for the elephants, both in terms of the number of visits and their duration. We then observed that the mere presence of the beehives, whether they were active or not, considerably reduced (more than 70 %) both the visits to the site and their duration. However, the most interesting thing is that the elephants seem perfectly capable of understanding and taking into account the hives' level of activity. When the hives experienced entrances and exits of insects greater than 70 movements a minute, the sudden arrival of elephants close to the trees fell by 84 % compared with hives where there was little activity, and the duration of the visit dropped by 92 %. We can deduce that Apis mellifera adansonii clearly has a repellent effect on the forest elephant. It's the first time that this result has been established in relation to this species. Up until now, as regards using bees as a repellent, we only had information concerning the savanna elephant, whose habits are noticeably different from those of the forest elephant". As to why elephants behave in this way, it would appear that it is the buzzing produced by the bees, which the elephants perceive in much wider ranges than ours.

Double mission accomplished

But the interest of Steeve Ngama's study doesn't stop there. The fact of having – also – regularly quantified honey production in the experimental hives demonstrates that this traditional "function" of the bee is, under certain conditions, perfectly compatible with its effectiveness as an elephant deterrent. "Above 70 bee movements a minute (level of absolute efficiency because, beyond that, almost no elephant activity was recorded), the hives don't produce any honey, or very little", the PhD student from Gabon explains. "The best harvest (more than 3 kilos) occurred in the 30 to 60 movement per minute range, i.e. at a level where the bees are already a deterrent to the elephants. That said, we did have to deal with certain parasites attacking the hives, which had an effect on honey production. However encouraging, these results are still in the initial stages and there is a lot more work to be done".

Besides studying the data more extensively, the main issue now is the potential introduction of organised beekeeping – as a source of income – in these regions. Is it possible or not? Is it desirable or not? As regards the second question, the answer is already clear. "Many villagers, in Gabon, are interested in beekeeping programmes", Cédric Vermeulen says. "It's important to point out that the collection of "wild" honey today is very dangerous, and causes the systematic destruction of the colonies. Of course, several ethnic groups - Pygmies, in particular – have made a speciality of searching for honey. However, even though they protect themselves with leaves and smoke, the climber must climb some 10 or 15 metres; they are continuously at risk of being stung and falling, and they have to plunge their hands in the hole in the tree occupied by the insects to attempt to reach the honey! Moreover, the swarms are difficult to find in the forest. Beekeeping is less dangerous for both humans and bee colonies. Above all, it's an interesting alternative to poaching and an appreciable source of income for village populations". 

Elephant foret ruche

A rather short-tempered bee

As for the feasibility of the such programmes, the first systems are already on trial in Gabon, in the Crystal Mountains National Park to be exact. They are looked after by zootechnic teams from local research institutes and are also supported by private firms who supply the equipment. "With this type of approach, we're at the intersection of two mutually-enriching disciplines: zootechnics (breeding a little-known species of bee), supervised by Professor Jérôme Bindelle, co-supervisor of the thesis, and conservation biology (the protection of the forest elephant); with the improvement of the inhabitants' living standards as a backdrop. There are still a lot of things to understand – and that's what Steeve Ngama's doing for the moment, now he's back in Gabon. For instance: what's the physiological condition of the elephants the most attracted by the crops (by analysing their excrement and hormone levels)? What are the most attractive factors, in the crops, for the animals: the actual crops, the wild plant species or the fruit in the trees growing wildly around the cultivated plots? What would be the optimum amount of hives likely to constitute a truly effective barrier against the incursions? We could also test the sensitivity of the forest elephant to different sound frequencies, in order to better understand what's bothering it or what aspect of the bees' presence serves as a warning...

Hence, many issues to be solved before moving onto wide-scale concrete operations. We must also remember that Apis mellifera adansonii isn't ready to be domesticated, however charming the animal researchers or the villagers concerned. Mentioned by Steeve Ngama in his works (1), one anecdote says a lot about its tenacity when receiving an unexpected visit from a human. "The bees that were disturbed during the collection of honey (editor's note: from the test hives) continued to attack the invaders some thirty minutes later up to a distance of 200 metres from the hive", the expert tells us. "Some of them even went further and pursued us right into our vehicles". Thus, it is recommended that if a highly active hive is opened during the day, all domestic animals and humans must be evacuated within a radius of... 250 to 500 metres. In Africa, with this type of hymenopteran, it is better to approach these elephant hunters at night...

 

(1) These were published in May 2016 in Plos One, under the title "How Bees Deter Elephants: Beehive Trials with Forest Elephants (Loxodonta africana cyclotis) in Gabon". Steeve Ngama, Lisa Korte, Jérôme Bindelle, Cédric Vermeulen, John R.Poulsen.


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