Man changes nature at such a rate that species may not be able to adapt, leading to a major extinction crisis, scientists say. Some numbers:
- One in four mammals, one in eight birds, one in three amphibians and nearly half of freshwater turtles are under threat, according to the World Conservation Union's (IUCN) Red List.
- At least 15.589 species are at risk of extinction, according to the 2004 Red List, ie 7.266 animal species and 8.323 species of plants and lichens.
- The rate of disappearance of species is 100 1.000 times greater than the natural rate (ie the rate measured during geological time and due to the normal renewal of ecosystems).
- In total, since 1500, 784 animal and plant species are considered extinct, and additional 60 only survive in captivity or culture.
- Next to emblematic species, like the dodo (a kind of big pigeon unable to fly), disappeared after the arrival of the first settlers in the islands of the Indian Ocean to 1740, the big penguin in the northern hemisphere, the Galapagos elephant turtle or the Tasmanian wolf, thousands of unknown species disappear each year.
- The man has described only 1,75 million species out of a total estimated between 10 and 30 million.
- For each tropical plant that disappears, it is estimated that about 30 associated species disappear. For each tropical tree, 400 species disappear.
- A mean global warming could lead to the disappearance of 15 to 37% of the species, according to a modeling carried out on a thousand plants and animals in 6 regions particularly rich in biodiversity of the globe (Thomas, Nature of 8 January 2004).
- Three-quarters of the world's population is cared for by plants, and 70% of our medicines are derived from plants (Nicole Moreau, CNRS)
- Systematists are discovering every year more 10.000 new species, mostly insects, and above all beetles that represent almost a quarter of the species described.
sources: International mail