User blog: Yassmine talhi

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by Yassmine talhi - Monday, 29 July 2019, 6:50 PM
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The incredible expansion of the human species over the past centuries has caused the disappearance of many animal and plant species. This mass disappearance is called the sixth extinction crisis. Its peculiarity with respect to the previous ones is its speed 1000 to 10,000 times faster and which continues to accelerate exponentially, but also that it is due to the success of a single species, the Man, which causes the disappearance of all others.

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Photo credit: sowaratfal

The incredible expansion of the human species over the past centuries has caused the disappearance of many animal and plant species. This mass disappearance is called the sixth extinction crisis. Its peculiarity with respect to the previous ones is its speed 1000 to 10,000 times faster and which continues to accelerate exponentially, but also that it is due to the success of a single species, the Man, which causes the disappearance of all others.

Men's alteration of their environment has unprecedented effects on the distribution and abundance of species, on ecosystems and on the genetic variability of organisms.

Causes of extinction

The primary causes of biodiversity loss are demographic, economic and institutional factors, including an increasing demand for land and biological resources as a result of human population growth, production, consumption and trade. global, associated with the inability of people and markets to take into account the long-term consequences of environmental change and the overall biodiversity values ​​(Paris Declaration on Biodiversity, 2005).

The main causes are habitat loss and fragmentation, biological invasions, overexploitation of species, pollution and global warming.

These factors act either separately or in combination, increasing their risk of extinction. This is the case, for example, of a species that suffers from a loss of habitat, which is therefore weakened, and which will be exposed to exploitation by humans.

The extinction of a species may also be due to the extinction of one or more species on which they depend; this phenomenon is called coexistence. This phenomenon can be illustrated by the example of the Iberian Lynx which has specialized on the predation of the Wild Rabbit, and which is now in critical danger of extinction because of the fall of the numbers of its prey. More than 6,300 species would be co-threatened in the short term and whole ecological systems could disappear.

The human factor

The originality of this sixth extinction crisis is its link with human activities, but also its incredible growth which causes strong constraints on ecosystems and species.

Currently the land is home to 6.6 billion people. The doubling time of the population is currently 35 years! If it continued at the same pace, the human population would be in 900 years of 60 billion people, or 100 inhabitants per square meter.

This figure will obviously not be reached but it demonstrates that the impact of man on the natural environment is not ready to decline and that it will increase in the coming years if nothing is done. made.

It is therefore important to act now to limit this impact.

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photo source: abdelshop

IUCN Red Book

The International Union for the Conservation of Nature (IUCN) annually establishes a red list of threatened species. The IUCN Red List is the world's most comprehensive inventory of the global conservation status of plant and animal species. It is based on a set of specific criteria for assessing the extinction risk of thousands of species and subspecies. These criteria apply to all species and to all parts of the world (IUCN).

Thus, in 2006, 16,118 species are threatened with extinction worldwide. This balance sheet only takes into account the species that have been evaluated, ie just over 40,000 species out of the 1,560,000 described. 40% of the species assessed by IUCN are therefore threatened with extinction and given the limited number of species assessed (2.5%), the number of threatened species is likely to be well above 16 118.

Endangered species are therefore certainly underestimated, and all the more so since the majority of biodiversity is not yet known, only 1.5 million species are known, out of the 15 to 30 million existing ( according to the predictions of experts).

IUCN has established several criteria of severity: in particular, 1,541 species are critically endangered (extremely high risk of extinction in the wild, including 16 in France), 2,258 are at risk of extinction. extinction (very high risk of extinction in the wild, including 18 in France) and 4,591 species are vulnerable (high risk of extinction in the wild, including 99 in France). جبس بورد

Recall that the IUCN Red Book has no regulatory value, its primary purpose is to mobilize public and political attention on the urgency and extent of conservation issues, as well as to encourage international community to act to limit the extinction rate of endangered species.