The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) has published its first global report on invasive alien species. The document highlights that 218 of these species have led to the extinction of 1,215 plant and animal species worldwide.
Harmful effects of exotic invasive species
One of the key messages from the research carried out in 2023 is that exotic invasive species pose a serious threat to nature, its services to human life and the quality of life.
The document mentions that human activities have introduced more than 37,000 plant and animal species to different regions of the world, of which 3,500 species are considered invasive due to their negative impact on native species and ecosystems.
These impacts include changes in ecosystem properties (27% of reported impacts), competition for resources with other species (24%), predation of native animals (18%), and consumption of herbivores or plants (12%).
Invasive species: the case of beavers in Patagonia
One of the cases discussed in the publication involved beavers in the Patagonia of Chile and Argentina. “Beavers build dams and change entire ecosystems“.” Professor Sven Bacher, co-author of the report and professor at the University of Freiburg in Switzerland, said it was not just one species that was directly affected, but the entire community of species.
In fact, beavers are one of the species listed in a series of invasive species reports published by Mongabay Latam in 2022–2023. Their absolute number is now estimated at 100,000 to 150,000 individuals, with greater importance being attributed to the invasion that affected all the water basins of Tierra del Fuego.
“The trees of Patagonia – coihues, lengas, ñires, raulÃes and others – belong to the genus Nothofagus, cannot live in wetlands and take several decades to grow. In contrast, pine trees in the United States and Canada take five years to grow.said Alejandro Valenzuela, a bioecologist specializing in invasive species management and associate researcher at the National Council for Scientific and Technical Research (Conicet) of Argentina.
The result was devastating: As soon as the reservoirs created by the beavers were drained, the forest was replaced by exotic grasses and became the so-called “Beaver meadow“.
The Americas is one of the most vulnerable places to the problems of biological invasions, accounting for 34% of the impacts reported in the IPBES report. This is followed by Europe and Central Asia with 31%, Asia-Pacific with 25% and Africa with 7%.
With information from: