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The sixth great extinction: Invasive species
Since its existence, planet Earth has suffered five great extinctions. All of them were extremely devastating and caused by natural phenomena, such as changes in the atmosphere and the earth’s surface caused by meteorit rains, the explosion of a star, or movements of the tectonic plates. At present, the sixth great extinction is being presented.
Unlike the previous ones, the causes are not totally natural, but produced by the human being. This is due to the excessive consumption of natural resources and the use of fossil fuels that accelerate global warming.
Extension of the effects of the sixth great extinction
A group of Mexican and American researchers, led by biologist Gerardo Ceballos, have estimated the species extinction ratio in recent centuries. They focused on vertebrates because they are one of those who have more information.
In this investigation they noticed that 617 species of vertebrates have disappeared from their natural environment: 338 species have definitely disappeared and 279 can only be found in zoos. All this happened from 1,500 to the present, that is, for five centuries.The vast majority of vertebrate extinctions were recorded in the last century, and that is about two species of vertebrates disappear annually. This generates an imbalance in its natural environment and within the life of other living beings with those who shared habitat.
The areas with the greatest amount of extinctions are tropical and temperate, and the most affected are the closest to urban centers. They also warn that the great mammals of Southeast Asia are the ones with the greatest risk of disappearing. This is because it is the area with the highest percentage of loss of habitable territory.
Causes of the sixth great extinction
The origin of the sixth great extinction can be explained in broad strokes for human overpopulation. This generates the progressive disappearance of other species in the world for two reasons:
The great needs of natural resources and, therefore, of the overexploitation: the deforestation of large extensions, the excessive hunting, the intensive mining, etc.
An economy that revolves around the energy that is generated through fossil fuels. This contaminates the atmosphere and accelerates global warming, which negatively affects the ecosystem of many animals.This causes the habitat of great variety of animals to be affected. The species that have been extinguished in recent times have suffered a reduction in their habitat of up to 80 %.
In addition, the illegal mobility of species decreases the populations of some animals, such as: the illegal capture of exotic animals for later sale and illegal hunts to sell skins, bones and other materials. Likewise, the introduction of invasive species in balanced ecosystems negatively affects world fauna.
Likewise, it should be considered that the disappearance of a large number of species of plants and animals alters the ecological balance, which generates a waterfall effect. The extinction of a species affects others, and the effect will be greater or less depending on how important the role of the missing species within the ecosystem was.
Some extinct animals in the sixth great extinction
This mass extinction includes a wide variety of animals ranging from the mammoth to the dodo, through the Tasmania tiger and the Galapago Islands.
Also, in the sixth great extinction the disappearance of the megafauna is included, which occurred in the late last glaciation, between 9,000 and 13,000 years ago. All this is due to the effect of drastic climate change of the time and the intervention of the human being as its main predator.
A clear example of a species in high danger of extinction due to the sixth great extinction is the globe fish; Sushi fashion has decreased its population by 99.9% in the last 40 years. Atlantic red tuna has also been affected by this fashion. All this because they capture them when they are very young, without giving them the opportunity to reproduce.Another example is the effect of the disappearance of corals on marine diversity. The corals are dying at high speed due to the heating and acidification of the oceans. The corals in the Mediterranean and the great choral barrier in Australia are bleaching, that is, dying. Coral reefs are the food and habitat source of thousands of fish and mollusc species.
What can be done to stop this mass extinction?
According to many researchers, there is still the opportunity to stop the sixth mass extinction. This implies changing many of the current human practices, with the aim of reducing the emission of carbon dioxide and the reduction of fauna habitat.
It is recommended to increase protected areas and preserve with greater intensity and resources the species that inhabit areas near populated centers. This includes the decrease in consumption and depending on green technologies.