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In Brittany, gannets are on the decline

September 2021: There are plans for a marine extension to the natural reserve of the Sept-Iles archipelago in Brittany. This marine extension may include a quiet zone, closed to marine traffic between April and August each year. The quiet zone will be essential for rafts of northern gannets and other seabirds, the Sept-Iles being the most important seabird breeding area in metropolitan France. Unfortunately, this plan for a quiet zone is meeting the fierce opposition of local recreational sailors, who see the plan for a marine extension to the Sept-Iles terrestrial reserve as an attempt to their “freedom”. I wrote a tribune in Libération, explaining why this marine extension and the quiet zone are essential for seabird conservation: En Bretagne, les fous de Bassan battent de l’aile.

COVID19: the anthropause will not happen

Do you remember that end-of-the-world atmosphere during the first lockdown? A large part of humanity was under house arrest, and in many places nature was reclaiming its rights. Ecologists call this strange phase of our history the ‘anthropause’, especially in reference to the collapse of air traffic in the spring of 2020: global energy consumption fell by 6% last year. Like many people, I said to myself, “this is it, the industrialised nations are finally going to change their ways of doing things, to review their relationship with nature”.

One year and four million deaths later, I am less optimistic. Of course, the wilderness will have gained some respite, but beyond all the human tragedies, the ecological balance of the pandemic will be negative. Locally, successive confinements have facilitated a relaxation of environmental standards in the name of maintaining production, and the lack of controls has encouraged fraud. Industrial agriculture, deep-sea fishing, logging and construction have gone into plundering mode, while the state, bogged down in crisis management, neglects the surveillance of protected areas and has given up on respecting the environmental code. This same state is losing sight of the ecological transition, while public opinion is ready, and is severely repressing alternative attempts. At the European level, decision-makers remain unmoved, as illustrated by the recent debates on the Common Agricultural Policy and fisheries: while the modalities of agroecology and fisheries ecology are well known and would allow for the necessary transitions towards more environmentally friendly practices, the recovery plans support ecologically and socially damaging operating modes. On a global scale, it is now clear that the pandemic will exacerbate poverty and the already scandalous inequalities between social groups and nations. It is anticipated that the crisis will push at least 150 million more people into extreme poverty and worsen the status of women, particularly in urban areas of sub-Saharan Africa and Asia.
As we sink back into a consumer frenzy in the wake of deconfinements, and as our economic systems pursue illusory and deadly growth, ecological research reminds us that everything is linked: environmental destruction, health and economic crises, and social tensions; with dizzying global geopolitical consequences.

Helping each other to the top

The legionary ants are making rapid progress, hunting down their prey. Cockroaches, beetles, scorpions and tarantulas are all targets. Even lizards, snakes and small birds are attacked. Captured animals are stung, cut up and carried back to the bivouac, an aggregation of ants sometimes a hundred metres away.

In the forests of Panama, a bivouac of army ants can contain two million individuals. In order to feed them, the voracious larvae and the queen they protect, an efficient supply chain must be established. Long columns of legionnaires thus roam the ground. They consist of a caste whose sole function is to transport food, at the speed of ten body lengths per second (60 km/h in a 1.7 m human). These 5 mm creatures are the fastest of all ants, but sometimes they have to cross obstacles. When a bridge is needed, the legionnaires cluster at each end of the precipice until it is filled in, in a garland of bodies. If the column has to cross a very steep area, some ants stop in the middle of the slope and dig their claws into the substrate. In this way, the individuals become an animal ladder, a scaffold that fellow ants climb at full speed.

Is this altruistic behaviour governed by a collective organisation? In order to better understand this, colleagues (1) set up a small experiment, and a lot of mathematical models. In the path of a column of army ants, they installed a board whose inclination they could vary. The agile creatures tolerated slopes five times steeper than the steepest French departmental road, but beyond this threshold they built a scaffold in 80% of cases. This allowed them to cross even a vertical wall. The researchers believe that even if the benefit of scaffolding is collective, the decision to put it up is individual: the ant fixes itself to the slope when it notices that it or its neighbours are slipping, without waiting for an order from some headquarters. The scaffold-building legionnaires would therefore not use chemical communication, as they do when they capture a large prey. In this other case, the ants emit pheromones that attract a large number of conspecifics from the bivouac in order to take advantage of an abundant resource.

It is often assumed that coordinated animal behaviour requires thought and communication. In army ants, recent research indicates that movement in the forest remains rapid and fluid due to individual reflexes in favour of a common good. This high level of responsiveness increases the resilience of the small world of social insects; its ability to overcome obstacles and upheavals.

(1) Lutz, M. J., Reid, C. R., Lustri, C. J., Kao, A. B., Garnier, S., & Couzin, I. D. (2021). Individual error correction drives responsive self-assembly of army ant scaffolds. Proceedings of the National Academy of Sciences, 118(17).

Army ants (Ch’ien Lee/Minden Pictures/Biosphoto)

Nectar from urban gardens to the rescue of insects

A sunny spring day in the Deux-Sèvres. In my garden, bees and bumblebees are buzzing. Just on the other side of the dry stone wall, the agricultural plot is silent. Populations of pollinating insects are collapsing in Western Europe, mainly due to lack of food. Are populated areas refuges for all the little beasts?

Colleagues (1) investigated this question in 12 locations in the UK, comparing the amount of nectar produced by flowers in cities, agricultural areas and protected areas. To do this, they collected as much nectar as possible from the different flowers with a micropipette, becoming foragers themselves.  To their great surprise, there was on average no more nectar available for insects in the city than in agricultural areas and protected areas. However, within urban areas, some fully concreted habitats were extremely poor, while home gardens produced 85% of all available nectar, four times more than public parks. Thus, insects have much more food available to them in a garden than on an agricultural area. This urban nectar comes from a wide variety of plants, which contributes to its quality and extends the period of the year during which it is available. The second surprise was that 83% of the nectar in the gardens was produced by exotic plants. These species are often considered to be “beautiful and useless”, as they do little to benefit local biodiversity. Some are even invasive and potentially harmful. In fact, the study by British academics indicates that exotic flowering plants may have become essential for the survival of insects in our urban landscapes. Of the 536 flowering plants they studied, the scientists point out that species such as borage and butterfly tree (from the Middle East and China respectively) are excellent sources of nectar. For public parks, they recommend reserving certain areas to grow mixed flowers, which produce 16 times more nectar than a lawn.

This study is sure to delight urban gardeners, where flowering plants are now taking on a militant air; I’ll be thinking of them as I watch the bees foraging in the borage beds that bloom on the edge of my vegetable garden.

(1) Tew, N. E., Memmott, J., Vaughan, I. P., Bird, S., Stone, G. N., Potts, S. G., & Baldock, K. C. (2021). Quantifying nectar production by flowering plants in urban and rural landscapes. Journal of Ecology 109: 1747-1757.

Bombus pascuorum (Photo credit: Getty)

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