Impact of Humans on Biodiversity

The incredible expansion of the human race of the past few centuries has caused the extinction of many species of animals and plants. This mass extinction has been qualified as the sixth major extinction crisis. The difference of this crisis compared to previous one is that it has happened 1000 to 10 000 times quicker and isn’t showing signs of slowing down. In fact, it is still accelerating exponentially. It is also unique as it is down to the success of a single species, Man, which is creating the extinction of all others.

The changes Man is doing to the environment has unprecedented effects on the the abundance of different species, the ecosystem and on the genetic variation of different organisms. 

Causes of extinction

The primary causes of this erosion of biodiversity are of demographic, economic and institutional nature. Mainly, the increasing need for land and biological resources because of the growth of the human population, production, consumption and commercialisation of the world associated to the inability of people and markets to realise the long term consequences of environmental changes and values of biodiversity (Declaration of Paris on biodiversity, 2005).

The main causes are the loss and fragmentation of habitats, biological invasion, over-exploitation of species, pollution and climate change.
The factors act either separately or together, raising the risk of extinction. This is the case for example of species victim of habitat loss, and therefore weakened and will be exposed to human exploitation.

The extinction of a species can also be down to the extinction of other species that it depends on, this is called co-extinction. A prime example of this is that of the Iberian Lynx that was specialised in hunting rabbits and is now in critical danger of extinction due to the dramatically rapid drop in population of its prey. Over 6300 species are under threat in this way. In the long term, entire ecological systems could disappear.

Iderian Lynx extinct due to the impact of humans on biodiversity

The human factor

This sixth extinction crisis is unique due to its link to human activity and the growth of the human population which is putting pressure on other ecosystems and species. Currently, the planet is home to 7,5 billion people. The time it is currently taking to double the worlds population is only 35 years. If this continues on the same level, there will be 60000000 billion people on Earth in just 900 years. Meaning for every square metre of the planet, there will be 100 people.

This figure obviously won’t be reached. However, it means the impact man has on the world isn’t reducing and instead is growing faster than ever before.
Therefore, it is important to put an end to this impact.

Red list of the ICUN

Every year, the International Union for Conservation of Nature (ICUN) sends out a red list of endangered species. This red list makes up the most complete world inventory of plant and animal species. It is based on a number of precise criteria to evaluate the risk of extinction of thousands of species. These criteria are relevant to every species and every part of the world.

In 2006, 16 118 species were under threat. This total only takes into account species that were studied. This was about 40 000 out of a total 1 560 000 known at the time. 40% of all species studied by the ICUN are under threat of extinction and as only a small amount of all species were studied, the number is surely a lot higher than 16 118 endangered species.

Numbers of endangered species therefore are most definitely underestimated. Even more so as we still have only discovered a fraction of the entire biodiversity.  In fact, only 1,5 million out of an estimated 15 to 30 million species are known to us.

The ICUN has established many severity criteria. From them, we learn that 1 541 species are in critical danger of becoming extinct. 2 258 species are said to be endangered. 4591 are described as vulnerable. 

Remember that the ICUN red list has no regulatory value. Its aim is to direct the public attention towards this worldwide emergency. It also aims to create a momentum of willingness to change and limit the risk of mass extinction.

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