“This biodiversity that we have created is precious”

The biodiversity is in crisis. To not know it, you would have to have lived in a cave for several years as the media talk about it. The panda, the tiger or the polar bear are threatened. Like a million others. Among which, above all, species much more ordinary after all. Like a third of the birds that nest in France. Species which however have this in common… to be all wild!

And today, it is on other animals, other plants, that the Academy of Technologies draws our attention. Domesticated species whose diversity is also called into question. “We don’t talk about it much, but the erosion of this biodiversity is also beyond doubt”exposes for us Bernard Chevassus-au-Louis, biologist and ecologistformer director of the National Institute of Agronomic Research (Inrae) and member of the Academy of Technologies. “This diversity that we have in a way created is nevertheless precious. Like what some are doing for the conservation of our cultural heritage, we should work to preserve this natural heritage. »

Humans creating biodiversity

Let us remember above all that domesticated biodiversity is very different from wild biodiversity in that humans – through their activities – initially played a major role in its growth. When it was created in 1854, the one that would become the National Society for the Protection of Nature (SNPN) in the 1960s bore – more or less – the name of the Acclimatization Society. An evocative name to say the least. Since its stated aim was to introduce and acclimatize to France useful or ornamental species and to improve and then multiply new breeds.

“The selection operated by humans has led to a veritable proliferation of animal breeds and plant varieties. The result of a domestication carried out under different agronomic and ecological conditions. For different uses, too. Some animals were chosen for pulling loads, others for butchery and still others for producing milk. And even among the draft animals, there had been created differences between the horses intended to draw stagecoaches, to haul boats or to plow fields. We even had ‘right-wing’ oxen and ‘left-wing’ oxen.details Bernard Chevassus-au-Louis.

This selection has long been made solely on the basis of phenotypes. Understand, based on the apparent characters of individuals. Then genetic got involved. “I was part of this generation that wondered how to go back from the phenotype to the underlying genetics”, recalls the biologist. With the aim of continuing to improve the races. “Today, the question is completely reversed. Because in minutes you can have access to thousands of footage DNAHas genomes whole. The idea has become, starting from a DNA, to understand what phenotype it can lead to. »

Genetics as an indicator of the decline of domesticated biodiversity

We now know that there is a certain redundancy, especially in plant varieties. “On varieties that may have been given different names because they had been bred in different places, but which, from a genetic point of view, turn out to be very similar. » This is why estimating biodiversity from seed catalogs seems a rather perilous exercise.

“We also realize that there are what can be described as “false large races”. Abundant breeds, but with low genetic diversity. Conversely, there are breeds that are less abundant, but for which the genetic diversity is greater”, explains Bernard Chevassus-au-Louis. He gives the explanation of the Limousin, a cow much more abundant than the Frisian Pie-Black, but which presents a much less genetic diversity. “The result of homogenization work carried out by humans. »

“In the 1950s, at the beginning of modern agricultural research, it was considered that it was up to the private sector to create new breeds, new varieties. The problem is that this private sector follows economic logic. But today, should we always consider that only the races and varieties which correspond to an economic optimum should be kept? »

The value of the option

This is the whole question posed by the notion that scientists call option value. First, because the economic optimum of one era is not necessarily that of another. “We have long considered that the important thing was to produce milk in quantity, whatever its quality. Today, some uses require high levels of protein or in materials specific fats », notes Bernard Chevassus-au-Louis. In the same vein, the question that arises in the face of the reduction in meat consumption in France. “We have two options. Take advantage of this to produce less meat, but higher quality meat from cows more suited to more heterogeneous environments and resource conditions. Or continue to produce intensively with plenty of water and food. » Especially since there is also the question of the climatic context. This ongoing warming in the face of which maintaining options could prove crucial. It is with this in mind that seed banks have been devised. somewhere in Arcticthe Svalbard World Seed Vault is now home to more than a million seeds from all over the world.

“The idea is laudable. But we must not forget that while these seeds sleep in a fridge, nature continues to evolve. When we need them, these plants may find themselves confronted with new pests or more aggressive pests than those they knew. This bracketing of genetic diversity is not the miracle solution.believes Bernard Chevassus-au-Louis.

The problem also arises with animals. It is of course possible to freeze sperm. “But how do we conserve animal culture. It is for example possible toimplantin a very common dairy cow, embryos of the entire Bovidae family. A good old Holstein can thus give birth to a water buffalo. She will take care of it as if it were a small Holstein. » And that’s where it hurts. Because the water buffalo is supposed to know how to graze in the water. “That, a Holstein mother cannot do. She can’t pass it on to him. » When it comes to conservation, therefore, nothing seems able to replace real animals, real plants. “To maintain option value, coevolution must be preserved. »

How to preserve domesticated biodiversity?

One of the avenues envisaged to contain the decline of domesticated biodiversity is to promote it through its products. “By stating that Roquefort can only be produced from Lacaune sheep’s milk, for example. » By also counting on new consumer purchasing behavior. “Comté is produced from cow’s milk which must be collected within a radius of only a few kilometers from the fruitière – this is where the cheese is made. Enough to define vintages, a bit like for wine. Because depending on the quality of the herbs – whether they come from meadows or from higher altitude areas – that the cow eats, the flavors of the cheese will be different. It’s a way to rediscover the taste of good things. And to remind us of this sentence of Claude Lévi-Strauss : “It is not enough for a food to be good to eat, it must also be good to think about”. »

Another avenue to consider is the one on which some ordinary citizens have embarked. These associations which organize themselves to conserve an animal breed or a plant variety which lacks interest in the production of mass. “To facilitate harvesting in the fields, the cabbage seeds that are planted all grow at the same time. But in your garden, the heterogeneity of certain traditional varieties can be an advantage. By growing the sprouts over several weeks so you can take full advantage of them. We must encourage these initiatives that promote biodiversity in interaction with its environment. »

Encourage them also through public interventions. Who come in support of this type of initiative. “Anything that can be done so that these breeds, these varieties are seen as a natural heritage that people want to keep is good to take. Because to imagine that we could start from scratch, start fromwild species as our ancestors did, it is a mirage. Even with the support of modern technologies, it would still take centuries. »