“The bees are starving!
When the Fermes de Gally announced the first results of their innovative study, the Plaine de Versailles association, surprise, wanted to extend the experience to the scale of its territory, which covers 22,000 hectares (agricultural for half) spread over 27 municipalities and five inter-municipal authorities in Yvelines.
For three years, she had the pollen collected by bees from three apiaries located in locations typical of the landscapes of the Plain analyzed: the first is close to the town of Plaisir and the forest, another is in an agricultural zone close to villages and forest and the last one is isolated in agricultural zone.
The results have just fallen: "The biggest cause of death, apart from the parasite, is not linked to pesticides and heavy metals but to nutritional deficiencies: bees lack flowers to forage, both in quality and quantity", deplores Marie Martinez, leader of the association.
"Nature does things well, let's do everything else": determined to implement their adage, the Fermes de Gally (Yvelines), between the forest of Marly and the hills of Saint-Cyr-l'Ecole, are in little care for the bees.
The family business, which brings together three open farms, one picking, a horticultural farm and two grain farms, plays on all terrains.
"Colonies are disappearing every year"
Farmers and gardeners since 1746, they cultivate “almost everything”, summarizes Bruno Gansel, one of its managers.
This is to say if they "need pollinating insects".
So for thirty-five years now, they have also become beekeepers: some 200 hives have joined the different sites.
Only, they quickly "noticed that colonies disappear every year".
However, Les Fermes de Gally took care to choose the locations of the different apiaries so that they “do not compete”.
"Bees should not spend more energy going to find food than what they bring back," sums up Bruno Gansel.
So normally, they forage within a radius of 1.5 km around the hive.
"
The farms of Gally operate nearly 200 beehives between the forest of Marly and the hills of Saint-Cyr-l'Ecole, in the Yvelines./LP/AF
Intrigued, and especially annoyed by this mysterious mortality, they wanted to discover the cause.
At Fermes de Gally, we were already familiar with two major scourges: phytosanitary products, since bees are part of insects, and parasites, the best known of which is varroa.
"The one we had not identified is the food cause," adds Bruno Gansel, still astonished.
Like us, she needs a varied diet to avoid deficiencies.
And this, throughout the season.
"
A pollen trap installed at the entrance to the hives
The decision was taken to embark on one of the first French scientific studies with BeeOdiversity, a Belgian laboratory, led by Bach Kim Nguyen, author of a doctoral thesis dedicated to the protection of bees.
To analyze the bees' environment, a pollen trap is installed at the entrance to the hive, to collect a sample of what the bees bring back.
"It's a great way to assess the environment", boasts the co-founder of the start-up, recalling that a colony of bees, "it is 4 billion flowers collected each year".
“They have a sampling force that we could never achieve,” he marvels.
2018, year 0: samples are taken at the beginning of May, end of June and end of July on two hives, one on the edge of the Gally harvest, not far from the Marly Forest and the Chèvreloup arboretum, the other at the Ferme Ouverte de Gally on the edge of the park of the Palace of Versailles.
In these three series of samples, the laboratory counts 17, 13 and 9 varieties of pollen.
"This is the initial photo, the master stallion", emphasizes Bruno Gansel.
The same process will be repeated for the next two years.
"These results surprised us"
And it is also an unexpected finding: "Whatever the sample studied, the pollen diversity is clearly lower (15% to 47% depending on the period studied) than the average of that observed on all the sites studied by BeeOdiversity" , we are alarmed at Fermes de Gally.
"These results surprised us because we are not in a monoculture zone", emphasizes Bruno Gansel.
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However, the bees need enough pollen to feed the larvae but also nectar to produce the honey from which they draw their energy in winter, when they form a body by flapping their wings around the queen to keep the hive at 23- 24 ° C.
Insufficient and unbalanced food therefore limits the development of colonies and exposes them to a risk of mortality.
A colony of bees collects an average of 4 billion flowers every year! / DR
"These insects are useful to us and if we preserve them, we preserve all the other pollinators", insists Bruno Gansel.
However, "75% of our food crops and nearly 90% of wild flowering plants depend, at least in part, on pollination by animals", according to the report of the Intergovernmental Science and Policy Platform on Biodiversity and Services ecosystem (IPBES).
New cultures developed
“But we have the means to act!
»Says Gally Farms, which now take into account the needs of bees.
“We have reviewed our rotations and cleared areas to cultivate honey plants (producing pollen and / or nectar) in the perimeter of foraging beehives, continues Bruno Gansel.
For three years, we have devoted several hectares exclusively to the cultivation of phacelia, sainfoin, borage, clover, centauries… These productions are not harvested.
They are sown and then maintained only to provide diversified food for bees and more generally for pollinators.
»It can be complete plots, replacing the grass strips around the crops with flowering strips.
Last year, they also alternated the rows of corn and the rows of honey.
And already, the results exceed their expectations: “Last year, after three years of honey crops, pollen analyzes on our two hives show a higher pollen diversity (+ 4.5 to + 59% depending on the period studied). the average of the other sites studied by BeeOdiversity ”.
Of course, the trend has reversed.
But are these efforts visible on the health of the hives?
“Last year, we had little mortality, a very good harvest, and it had been years since we had had spring honey,” announces Bruno Gansel.
But if I made the direct link, I would tell of carambouilles, he nuances.
Certainly the bees had very good reserves.
But we also had exceptional weather during the first containment and a very big spring flowering.
It will take some time to study the long-term benefits.
Raise awareness, convince and push to action
But the association of the Plain of Versailles is determined to take its pilgrim's staff to go and teach its members: local elected officials, 70 of the 120 farmers in the area, around sixty inhabitants, around twenty. associations and a dozen companies.
But not only.
“The idea is to mobilize all the players in the area, including golf courses and aerodromes,” enthuses Marie Martinez.
So that everyone can work on their own scale: "Mow lawns a little later, respect the periods for trimming hedges (prohibited from April 1 to July 31), do not deprive the bees of the late flowering of ivy by cutting it too much. early, sow a mass of flowers ... "And remember that the whole ecosystem is linked:" The bees are very dependent on the chestnut at the beginning of the season (
when other flowers are rare, note
), yet they are overwhelmingly slaughtered in an attempt to curb the progression of the ink disease, recalls Marie Martinez.
But there is no consultation to anticipate this loss and compensate with suitable plantings.
"
To motivate them, Marie Martinez already holds her slogan, for after confinement: "They are the sentinels of the environment in which they operate.
If it's good for them, it's good for us!
"