The island that banned hives: can honeybees actually harm nature? | Bees

Giannutri’s isolation attracted scientists here. They were looking for a unique outdoor laboratory to answer a question that has long intrigued environmentalists: could bees reduce their wild cousins?

To respond to this, they carried out a radical experience. While Giannutri is too far from the continent for bees to go there, 18 hives were installed on the island in 2018: a population relatively contained recently established. The researchers obtained permission to close the hives, effectively eliminating most bees from the island.

When the study began, the human population of the island has temporarily doubled, while teams of scientists have moved through the bees that follow the bees. Then came the prohibition: they closed hives on the days selected during the maximum food period, keeping the bees in their hives for 11 hours a day. The local populations were skeptical. “For them, we did stupid and useless things,” explains Dapporto. But the results were convincing.

“” Wow “was my first answer,” said the principal researcher Lorenzo Pasquali, of the University of Florence. When the data gathered, “all the results were in the same direction”.

The results, published in Current Biology earlier this year, revealed that during the four years after the introduction of bees, populations of two vital wild pollinators – Bumblebees and Anthophora – fell with “an alarmant” of 80%. When the bees were locked up, there were 30% more pollen for other pollinators and the species of wild bees were seen more frequently. Scientists observed that wild species seemed to take their pollinating time during locking, displaying a different food search behavior. “The effect is visible,” says Dapporto.

World bee battle

In terms of pure abundance, the Western bee (Melllifera API) is the most important species of the most important pollinator in the world in wild ecosystems.

Originally from Africa, the Middle East and South Europe, bees were sent around the planet by humans at each continent except Antarctica. The battles playing on this small Italian island are likely to be taken up in ecosystems everywhere.

While the number of bees increases (trained by commercial beekeeping) indigenous pollinators decrease worldwide due to the loss of housing, the rupture and the use of chemicals in agriculture. But we only start to understand how the big bees boom could also wreak havoc on wild pollinators.

In the south of Spain, where beateurs numbers have more than tripled since the 1960s, research shows that managed bees pouring into woods rich in flowers after the flowers of orange culture. The result: increased competition with wild pollinators.

During the annual almond flowering of California, around 90% of the United States managed bees are recruited to pollinate, with ruptures of beekeepers across the country to meet demand. “For this period of about a month, the impact of bees on native pollinators is probably enormous,” said Dillon Travis from the University of California in San Diego. During the season out of season – when bees are less requested – beekeepers often keep them in wild ecosystems. “Indigenous pollinators must compete with millions of bees for limited food sources.”

If the conditions are correct, the bees become wild and install colonies in the wild. A 2018 study examining the presence of bees in natural ecosystems found them in 89% of the sites.

In California, wild bees are becoming more and more in large numbers in natural ecosystems hundreds of kilometers from almond fields.

Honey takerovers

Each spring, after the winter rains, the coastal brush landscape of San Diego burst into life. The sagebrush, white sage and buckwheat deploy their leaves, throwing soft aromas into hot air. These images and odors welcomed the graduate student Keng-Lou James Hung when he started studying this region in southern California in 2011, at the age of 22, after a reputable biologist told him that it was one of the richest bee habitats in the world.

The landscape has all the characteristics of a virgin ecosystem: no tractor has plowed the earth, no cattle collapsed it; Few humans walk here. “You can assimilate it to the primary growth of the Amazonian tropical forest in terms of intact and non -disturbed ecosystem,” explains Hung.

When Hung started his research, however, what he discovered disconcerted him. “I arrived on my sites in the field and all I saw was bees,” he recalls. “Imagine as a passionate enthusiasm: you arrive in an immaculate forest and all you see is wild pigeons. This is what was going on with me when I set foot in this habitat. It was a shock.” The bees were everywhere – nesting in public service boxes, grounds of ground squirrels and rocky crevices.

In July, Hung – now deputy professor at the University of Oklahoma – published a document noting 98% of all bee biomass (that is to say the weight of all bees) in this area was wild bees. They removed around 80% of the pollen on the first day when a flower opened its doors, published in the journal Insect Conservation and Diversity.

These high rates of pollen extraction leave little for more than 700 species of native bees in the region, which need pollen to raise their offspring. Some of these species have not been seen for decades.

Hung believes that the social structure of bees gives them the advantage. Using “the spirit of the hive”, they communicate the locations of the plants and remove most of the pollen early in the morning before the native bees started to seek food. Most other bees work like unique agents, making decisions in isolation.

“It’s like a local grocery store that tries to compete with Walmart,” said Hung. “Once they have escaped and settled, we can do very little to really stop bees. These are very powerful and resilient creatures.”

In 1956, “Africanized” experimental bees were accidentally released from a ruquette of research in São Paulo, Brazil, distributed through South and Central America and California. Their expansion was described as one of the “most spectacular biological invasions of all time”.

Broader ecological effects

The fragmentation of housing, chemical use in agriculture and the increase in temperatures are the main engines of the declines of pollinators, but in areas such as in San Diego, it is probably that bees are also a significant contributory factor. “It is very difficult to imagine a scenario where only one species can eliminate four -fifths of all pollen … without having too much impact on this ecosystem,” explains Hung.

Not only is it bad for native wild bees, but it can have effects throughout the ecosystem.

Studies have confirmed that plants from the County of San Diego are less healthy when they are pollinated by non -native bees. Potential impacts include fewer seeds in germination, and those that do it can be smaller and produce less flowers. “This can create a” extinction vortex “, explains Travis, where less healthy plants reproduce during generations until they can no longer survive. “I do not know any study that determined that bees are beneficial when they are not from, excluding agricultural areas,” he said.

In some parts of Australia and America – where bees are not from – they can reach densities up to 100 colonies per square kilometer. In regions like Europe, where they are from, the image is different.

Last year, there were about 75,000 free bee colonies across the United Kingdom, which was the first to quantify the density of these colonies. Based on these estimates, more than 20% of the UK honeys population could be wild. “In Europe, the bee is an native species and low densities of wild colonies are natural components of many ecosystems,” explains researcher Oliver Visick from the University of Sussex.

Visick has found densities up to four wild colonies per square kilometer in the historic deer parks of Sussex and Kent. “To these densities, it is unlikely that the wild colonies have a negative impact on other wild pollinators,” he said.

In ecosystems where bees are introduced, scientists say that there should be more advice on large -scale beekeepers who keep their hives after crops have flowered to reduce their impact on native species. In other regions, such as islands, relocation or elimination may be possible.

The Sans Shelter Island

On Giannutri, when the researchers told the authorities of the National Park to their results, they prohibited bees on the island.

The island, which is part of the Tuscan archipelago national park, has been homeless for more than a year and can now serve as a precursation tale to other protected areas that plan to introduce bees. Since the hives were removed, at least one of the species that scientists have followed seems to have increased slightly.

The story that takes place on this small Italian island and the San Diego’s scruption show that bees may not be the universal environment guards that we paint them, and calls into question the popular opinion that they are the best way to save Noseding’s pollinators’ numbers. Uncruved, they can throw a shadow on fragile ecosystems that some might believe that they help preserve.

When scientists returned to Giannutri,, “It was a bit weird to go back to the island this year without bees. We used to see them everywhere in the whole island, ”explains Pasquali. “I was happy to observe the island in this new condition.”

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