Lots: When alien species invade the circle

Many more and more exotic species can be observed in the batch: animals and plants too … Focus on the specimens that are frequently found in the section.

Kind of weird, quesaco? More commonly called “invasive,” specimens that have been introduced to the department, voluntarily or not, when not part of the local biodiversity. Often they have a negative effect on native species (well established in the department). Update about these other animals and plants.

Like a fish in the water

The waters of Lot, the lakes mainly, are more or less inhabited by large fish and shellfish. Starting with California lobster. These little beasts live in the same type of habitat as the white-clawed lobster, a species of lotois. The first are carriers of a health disease that kills the second. A minor concern for the fishing federation.

On the fish side, catfish descended from the Danube. When he arrived, “there was a wave of panic.” Some believe that they will eat everything in their path,” explains Laurent Frederic, technical director of the union. But these individuals, who can measure more than two meters in size, “it is just another predator added to the food chain,” concludes the world.

There are two other species introduced by man: sunfish and catfish. The latter is clearly declining in lot.

plants in the flora…

Let’s talk a little, let’s talk about plants. Jerome Dow, director of the Invasive Exotic Plants Project at the Conservatoire Botanique National Midi-Pyrénées et Pyrénées, points out that most of the exotic plants that invade the lotus disturb the department’s biodiversity. The vast majority of them come from America, were forcibly returned (contaminated seeds) or voluntarily (related to the use of: garden, development and decoration of the pond …).

Datura, nicknamed “devil’s weed”, a species that has an effect on health: it can cause moderate or severe poisoning for several days. Very small amounts are enough to provoke a reaction. Avoid handling them by hand at all costs.

There is also the ragweed that arrives through contaminated sunflower seeds. More and more agricultural sectors are affected by the invasion of this plant, with up to 80% of crops lost on sunflower farms.

… but also in the aquatic environment

These invasive plants do not spare the aquatic environment. We can cite maple neondo. It is a tree that was voluntarily submitted. Its seeds fly very easily and leave the farms where they land on the banks of waterways. “It’s their favorite environment,” says Jerome Dow. Largely found in riparian forests (vegetation at the edges of waterways), the Nijondo maple can quickly take precedence over other extant species (eg ash). “So the biggest risk is to have undiverse forest on the banks of the rivers. But we don’t know how the maple will react to global warming, or if disease arrives?”

The lotus also has a lot of water algae, especially in isolated ponds. In Dégagnac, the Palazat stream is covered by about 50%. If it gets too big, it could end up in a lot, which definitely wouldn’t be good news…

Jerome Dow does prevention: you have to find out which species before you plant it. “The conservatory is there for this. People can contact us if they have any doubts, or even any other representative of biodiversity, he explains. Avoiding the cultivation of invasive species is the biggest part of the battle.”

Focus on insects

On the insect side, it is possible to meet the box tree moth, the plane tree leopard, as well as the Asian hornet. How did these little creatures evolve? If we take the example of the Hornet, then the latter arrived in Lot-et-Garonne in 2004 by plane. But there are other ways: insecticidal products that can disrupt biodiversity, greenhouse, monoculture or even permaculture (they do not allow the soil to regenerate, so the pest always has everything it needs).

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