2023-09-04 14:17:18
At least 3,500 plants, animals and microbes, displaced from their region of origin by human activities, sometimes cause irreversible damage.
They cross the planet by plane or in container ships, before proliferating to the point of becoming a threat to their new environment. In 2019, the intergovernmental scientific platform IPBES
warned of the major role of invasive alien species in the erosion of biodiversity. Four years later, in Bonn (Germany), its 143 Member States have just adopted the first report drawing up an inventory of this scourge.
Read alsoThe sixth mass extinction of species is underway This document estimates that 37,000 species have been displaced by human activities from their original habitat. Among them, more than 3500 are identified as “invasive” and “harmful”. Taking advantage of the absence of a natural enemy (parasite or predator), these animals, plants, fungi and microbes, terrestrial or aquatic, have acclimatized so well that they have taken over their new ecosystem. Present everywhere in the world, including in Antarctica, they « can cause irreversible damage to nature, including species extinctions, as well as threaten human well-being»
underlines Hélène Roy, co-president of the evaluation within the IPBES.
The report was produced at the request of governments by 86 experts from around the world, who analyzed 13,000 scientific articles and contributions from indigenous peoples. According to the document, alien species are implicated in 60% of documented animal and plant extinctions. In Australia, wild cats and red foxes brought by British settlers contributed to the virtual disappearance of the bilby, a small marsupial with long rabbit ears. In Lake Victoria, Africa, the introduction of carnivorous Nile perch in the 1950s resulted in the rapid extinction of at least 200 unique species of fish, upsetting an ecosystem and undermining an entire traditional economy of the fishing. As for the black rat, the third most widespread invasive species on earth, it alone would be involved in the disappearance of around fifty species of birds…
$423 billion per year The rate of introduction and the threats linked to invasive species are increasing « significantly in all regions of the globe» , warns the IPBES, which attributes this dynamic to population growth, the acceleration of trade and tourism, land use change and global warming. The annual cost of the upheavals, estimated at 423 billion dollars (around 390 billion euros) in 2019, has quadrupled every decade since the 1970s. Prevention and control measures represent only about 10% of this financial burden. The rest corresponds to damage caused by invasive species – agricultural, viticultural or aquaculture losses, health consequences (pollen allergies, insect bites, infections by viruses carried by mosquitoes), damage inflicted on infrastructure (disruption of river traffic or rail, collapse of the banks) or even attacks on food security. «And even emphasizes Franck Courchamp, research director at the CNRS, this estimate only represents the tip of the iceberg, as research is still incomplete and we have no quantified information for most species.
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Read alsoInvasive species abound in the Mediterranean
While the majority of exotic species cross the oceans accidentally (mosquitoes hidden in tires, ants nesting in ornamental plants, etc.), some are imported voluntarily. But their harmful action can quickly eclipse the profit we hoped to derive from it. The Asian ladybug, for example, was deliberately introduced in the 1980s to control aphids, but this voracious insect, which knows no predators in our latitudes, spread by devouring local ladybugs. It can also attack fruits, flowers and crops. It is now recognized as one of the hundred most invasive species. However, biological dissemination and its impact are not inevitable, insist the authors of the report. «Biodiversity is resilient wants to reassure Franck Courchamp, and it is still possible to go back if we agree to act quickly and give ourselves the means. »
Last December in Montreal, the international community made a commitment, with the adoption of a new global framework for biodiversity, to reduce the introduction of invasive species by 50% by 2030.
fire ants To do this, scientists call for an emphasis on prevention by limiting the import of alien species, especially when they are identified as problematic. They recommend developing the surveillance in force at airports and ports, but also along highways and waterways, targeting containers coming from destinations « at risk » which can be quarantined and treated with insecticides. In New Zealand, the rapid detection of a few colonies of small fire ants, coming from the Amazon rainforest and capable of biting which may require hospitalization, has made it possible to eradicate the species on several occasions at a lower cost. However, note the authors of the report, only 17% of countries have adopted laws or regulations aimed at containing invasive alien species. «To win this battle, it is also essential to build on the awareness and involvement of the general public, especially tourists. believes Anne Larigauderie, the executive secretary of the IPBES. We need to be more aware of the potentially catastrophic consequences to which the transport of species from one continent to another exposes us.
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