Algae, crabs, parakeets: these overly invasive exotic species endanger biodiversity

In Honfleur (Calvados)an individual called in an intervention brigade. At the bottom of his garden, a pond is colonized by a Brazilian plant, a kind of very dense aquatic herbarium purchased several years ago in stores. “The plant is sold in garden centers for its oxygenating capacities, except that it is the completely opposite effect, since when it will have completely colonized the pond, there will be no more photosynthesis which will be possible for the algae present in the pond. pond, and therefore there will be an asphyxiation of the environment”explains Remi mandramember of the Norman brigade “Invasive alien species”.

The Brazilian watermilfoil is an invasive alien species, the kind of plant sold for aquariums or small ponds, and which proliferates if you are not careful. Thus, a stream is completely lined with another invasive plant from New Zealand. Underwater, the density is such that life is gradually dying out. “It is already such an important situation that we can no longer do anything at the manual level”says Jean-François Dufauxconservator of natural spaces in Normandy. The South American nutria, like the crayfish, from Louisiana to the Camargue or the Asian hornets, are fine in our latitudes and have no predators. This is called an invasive alien species.