Mathilde Beaulieu-Lépine - Le Devoir - 27 août 2025
« La plupart des vers de terre présents au Canada, surtout dans le Nord et au Québec, sont d’origine européenne », explique Jérôme Laganière, chercheur à Ressources naturelles Canada. En effet, la majorité des vers de terre au pays ne sont pas indigènes et ont plutôt été introduits sur le continent il y a quelques centaines d’années ... une grande partie des forêts canadiennes n’abrite toujours pas de vers de terre. Une étude menée au Nouveau-Brunswick a révélé que 60 % des forêts échantillonnées n’étaient pas colonisées ... En milieu agricole, les vers de terre sont vus comme bénéfiques : ils ameublissent les sols, créent des galeries et accélèrent la décomposition de la matière organique. Par contre, en forêt, leur présence bouleverse l’équilibre naturel. Les feuilles mortes forment une épaisse couche de litière et d’humus au sol. Celle-ci est essentielle à la germination des plantes de sous-bois et sert d’habitat à de nombreux insectes, amphibiens et petits mammifères. Les vers de terre peuvent réduire cette couche de 95 %, voire la faire disparaître.
Liens: Radio-Canada
My Forest Has Worms
New England Forests - October 27, 2018
Scientists call it "Lumbricus terrestris". Most of us know it better as ... the common nightcrawler ! Actually, it's not just the nightcrawler that's a problem, but a number of earthworm species, none of which belong here ... where the non-native earthworms have invaded the hardwood forests, they rapidly eat newly fallen leaves and small twigs, consuming the duff layer, and mixing it into the lower soil layers via their movements into the ground. The duff layer is not replenished as quickly as it is eaten, and disappears. Earthworm activity dramatically decreases the mycorrhizal relationships, and thereby harms the plants that rely on them and the duff layer. The makeup of the soil layers is changed, to the detriment of the forest community that has occupied the land for millennia. Worms break up the organic layer to the point where important elements such as nitrogen, phosphorous, and carbon are leached deeper into the soil, where young plant roots simply can't reach them. Herbaceous plants can virtually disappear, leaving the ground barren and brown. The soil becomes drier due to aeration by the worms. Compare this photo of stark, worm-damaged woods to those of the undamaged old growth forests above.
Scientists call it "Lumbricus terrestris". Most of us know it better as ... the common nightcrawler ! Actually, it's not just the nightcrawler that's a problem, but a number of earthworm species, none of which belong here ... where the non-native earthworms have invaded the hardwood forests, they rapidly eat newly fallen leaves and small twigs, consuming the duff layer, and mixing it into the lower soil layers via their movements into the ground. The duff layer is not replenished as quickly as it is eaten, and disappears. Earthworm activity dramatically decreases the mycorrhizal relationships, and thereby harms the plants that rely on them and the duff layer. The makeup of the soil layers is changed, to the detriment of the forest community that has occupied the land for millennia. Worms break up the organic layer to the point where important elements such as nitrogen, phosphorous, and carbon are leached deeper into the soil, where young plant roots simply can't reach them. Herbaceous plants can virtually disappear, leaving the ground barren and brown. The soil becomes drier due to aeration by the worms. Compare this photo of stark, worm-damaged woods to those of the undamaged old growth forests above.
