Orne. Burning, allergenic or suffocating: SOS Biodiversity fights against invasive plants

” HAS Alenconas in Orne, as in the whole Normandiethey suffocate other forms of life,” worries an expert.

We almost never talk about it in the media, but Normandy is facing a Serious threat: invasive alien species.

Among the invasive species, besides the formidable Japanese knotweed, ragweed and giant hogweed pose serious ecological and public health problems. To fight against their spread, sometimes very rapid, a special brigade is keeping an eye on things.

Biodiversity and public health

THE invasive alien species (IAS) are plants and animals that adapt easily to their new territory. They spread quickly, modifying ecosystems and competing with local flora and fauna. Japanese knotweed, particularly present in country of Alençon, and Pampas grass are some of them. Others can cause allergies and serious skin burns.

Targeted action

The Normandy Natural Spaces Conservatory fight against these silent threats.

Within it, Jean-François Dufaux ccoordinates the efforts of the Brigade d’intervention. Unique in France, with two teams, one based in Caen, the other in Rouen, its mission is to fight against the most problematic plants. “We target the most dangerous plants as a priority,” explains the head of the brigade. “We limit and eradicate certain species, such as Helm’s crassula.”

A recent success of the brigade is the eradication of ragweed in Angervillein Calvados, avoiding potentially very significant public health costs, with this plant which causes severe allergies.

Global challenge

“Invasive plants disrupt local ecosystems and cost around 390 billion euros per year to the global economy. They are responsible for 60% of rare species extinctions “, comments the expert to explain the seriousness of the issue.

These species adapt quickly to their new environment and multiply rapidly, occupying any free surface in their path. Some, such as giant hogweed and ragweed, cause severe disease and burns.

Managing knotweed

The brigade uses methods adapted to each plant.

For the Japanese knotweed, they recommend manual pulling to prevent the spread of fragments. The screening-crushing method is also used, but too expensive for individuals.

Introduced to Europe in 1860, Japanese knotweed quickly invaded riverbanks, fields and roadsides. It is, for example, very visible along the Nationale 12, between Alençon and Saint-Denis-sur-Sarthon. Jean-François Dufaux specifies that this plant “contributes to soil erosion and seriously disrupts natural habitats.”

Pour prevent its spread,he recommends to do not cut the knotweedunless it is a safety hazard: “If the intervention is essential, it must be manual to avoid dispersing fragments of the plant, which encourages its spread. On the roadside, where you had a ten-meter station, the following year it is twenty meters, if you do not take precautions. You have to understand that if you take a twenty-centimeter piece of cane, cut it into four and spread it, that will make four knotweeds!”

The expert therefore advises to avoid mechanical mowingwhich can disperse the fragments, to prefer pruning shears to control the cutting, to respect the legislation (for example, not to burn green waste), to compost under supervision, or even to leave the waste on site.

If Japanese knotweed, although not dangerous for human health, remains particularly problematic, the Normandy brigade, active for around ten years, prefers prioritize your interventions. It therefore focuses on the most dangerous plants such as the burning giant hogweed and the allergenic ragweed.

Giant Hogweed

In touch with Giant Hogweed Sapin the presence of sunlight, one can experience phototoxic reactions. This can cause burns up to third degree. The intervention brigade is trying to eliminate this plant in Normandy. “We uproot the plants before they flower,” explains Jean-François Dufaux.

Given the dangerous nature of the plant, to eradicate it, the brigade’s operators wear protective suits worthy of the Covid era . And it’s not easy, “you have to dig up to twenty centimeters underground, right down to below the collar, it’s a blister in the root,” comments the brigade leader. In short, nothing obvious.

The specialist advises not to go out alone against giant hogweed, a dangerous plant which requires to be cut and collected by professionals.

“The brigade’s interventions are supported by our funders: Water Agency, Ministry of the Environment, Normandy region and Europe.”

Wanted

To recognize Japanese knotweeds, giant hogweeds and other ragweeds, Jean-François Dufaux suggests to use applications like Pl@ntNet for an initial identification. “But when in doubt, always call an expert,” he insists.

Thus, the crassule de Helmsalso poses major problems. Native to Australia and New Zealand, it seriously harms biodiversity in the north-west of France. “It dominates aquatic environments and suffocates other forms of life,” worries the expert.

Sensitization

The Conservatory of Natural Spaces is also carrying out, at the end of June, training operations throughout Normandy, and therefore in Orne particularly in Briouze, at the Sées high school and in Mortagne-au-Perche. These sessions aim to raise awareness of IAS and promote good practices: “Fishermen are invited, for example, to clean their equipment,” explains the head of the brigade, “to prevent the spread of invasive plants. In Normandy, as in the whole territory, Community and individual participation is vitalto control these plants and limit their ecological damage,” concludes Jean-François Dufaux.

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