Invasive species are the main factor of extinction of nature, so their expansion must be reduced, said an expert from the International Union for Conservation of Nature (IUCN).
The director of the group specialized in invasive species of the IUCN, Pietro Genovesi, assured in a ceremony that these species alone are responsible for 16% of extinctions in the world, a percentage that rises to 40% in combination with other threats .
More than 23,000 species at risk of extinction
There are currently more than 79,800 threatened natural species, of which more than 23,000 are at risk of extinction, according to the IUCN.
According to current trends, up to 16% of mammals and birds could be invasive species if they are introduced in new places.
The specialist gave an example of the beaver, which has already destroyed more than seven million hectares in Tierra del Fuego, Argentina, while in Africa the proliferation of carob trees is making it difficult for many communities to access land.
At least 70,000 levees builtby beavers in Tierra del Fuego
At least 70,000 dams built by beavers in Tierra del Fuego give the magnitude of the catastrophic impact produced by the uncontrolled population of underwater rodents introduced in the middle of the last century with the intention of favoring the fur industry. The figure was surveyed by members of the Faculty of Agronomy of the University of Buenos Aires, which will now seek to implement management policies to contain this phenomenon.
The researchers estimated the cumulative length of levees at 2,300 kilometers, causing the flooding of about 100 square kilometers.
More than a hundred species have negative effects on health
More than a hundred species have negative effects on health, such as the water hyacinth, a plant that favors the appearance of mosquitoes that transmit malaria.
In 1989 the presence of the water hyacinth, native to Ecuador, was detected in Lake Victoria, located between Kenya, Tanzania and Uganda, the second largest in the world, with an area (69,484 km2). No one knows how it got here, but the fact is that without natural barriers that prevent its extension and stimulated its growth by the erosion of sediments rich in nitrogen and phosphorus and all kinds of untreated discharges, the plant now covers large areas of the lake. "More than 15% of its surface", assures Nyenge.
Janet Abramovitz affirms that the water hyacinth spreads like a dense green blanket with an unusual speed - "a single plant can cover 100 square meters in a few months" - and that it "reduces the oxygen level of the water, prevents the passage of sunlight and obstructs waterways and ports ”. In addition, and as if it were a curse, "the plant favors the reproduction of the malaria mosquito and other parasites."
Costs for Europe
In Europe, invasive species cost more than 12,500 million euros annually, Genovesi recalled, adding that "if rich regions pay a high cost, those in development are even more vulnerable."
The expert called for improving prevention and rapid response systems, including eradications, which can work especially on islands such as New Zealand, where the number of invasive mammals and insects has decreased with biosecurity methods.
The executive secretary of the UN Convention on Biological Diversity, Cristiana Pasca, insisted that sustainable development involves not only conserving biodiversity, but also making good use of natural resources and sharing the benefits obtained.
He considered that "much remains to be done" to meet the agreed goals for the preservation of biodiversity for 2020 and encouraged governments to act in the short time remaining, strengthening, for example, regulation to prevent pests.