We humans are in the midst of a major mass extinction. Many species are endangered or extinct. More than 1,400 bird species have already disappeared, twice the number previously thought. This has serious consequences for biodiversity.
Man leaves his mark everywhere in nature, and usually not in a positive sense. For example, many of the world's islands were once pristine natural areas teeming with life, but when humans arrived in places like Hawaii, the Azores, or Tonga, the fun quickly ended for existing species. For example, deforestation, hunting, and the introduction of other animals have led to the disappearance of many birds.
A few fossils
It was not clear for a long time exactly how many bird species became extinct, because numbers were only kept since the year 1500. There are only fossils from the period before that, and they are limited because the light bones of birds disintegrate over time.
Now British researchers have been able to make a better estimate with the help of statistical models. she write in nature Since the late Pleistocene era – about 130 thousand years ago – about 1,430 bird species have become extinct. This is approximately 12 percent of all birds. The vast majority of them have disappeared due to human activity.
No trace
“Our study shows that the human impact on bird diversity is much greater than previously thought. Humans have rapidly devastated bird populations through habitat destruction, overexploitation and the introduction of rats, pigs and dogs, which compete with birds for food and steal their nests,” said lead researcher Rob Cook. “We have shown that many species became extinct before records began, without leaving any traces.”
This has serious consequences for the current decline in biodiversity, explains researcher Søren Farbe from Harvard University University of Gothenburg Outside. “The world may have lost not only many magnificent birds, but also their important ecological function, such as seed dispersal and pollination. This has detrimental effects on ecosystems. In addition, many other animal and plant species that depend on birds for their survival have also disappeared.”
The end of the dodo
We know from fossils and other sources that approximately 640 bird species have become extinct since the late Pleistocene, most of them on islands where humans came to live. For example, the famous dodo has disappeared, as have the great auk and St. Helena's hoopoe.
But it is estimated that 790 other unknown bird species have disappeared. The researchers based their estimates on known extinction figures and previous research in the regions, which they compared to New Zealand. New Zealand is the only place in the world where all the bird species that lived there before humans arrived are known. The fewer studies conducted in an area, the less likely the fossil record is complete and the more estimated extinctions go undetected.
Another mass extinction
According to researchers, the largest extinction of bird species occurred in the fourteenth century. An estimated 570 bird species disappeared after humans arrived in the eastern Pacific, including Hawaii and the Cook Islands. This is almost a hundred times the natural extinction rate.
They believe a major extinction event also occurred in the ninth century BC, when humans arrived in the western Pacific, such as Fiji and the Mariana Islands. They also mention the current mass extinction, which began in the mid-1700s. Since then, the animals have not only suffered from deforestation and the spread of invasive species, but are also threatened by climate change, intensive agriculture and pollution.
in my hand
Previous research by the same authors suggests that there is a high chance that another 700 bird species will become extinct in the next few hundred years. That would be an unfortunate point: never before have humans caused such a large species extinction. But it's not too late, Cook says. “It is up to us to make more bird species extinct. Recent actions have saved a number of species, and we must now make greater efforts to protect birds by restoring their habitat.
According to many scientists, we are now witnessing the sixth mass extinction. Not everyone agrees with that. That's because it doesn't look that bad when you look at the Red List of Threatened Species International Union for Conservation of Nature (International Union for Conservation of Nature). But this includes only a small part of invertebrates, as we previously wrote on one basis Recent study. This is not true, because invertebrates make up the vast majority of biodiversity. If you include them, 7.5 to 13 percent of the two million known species on Earth have disappeared since the year 1500. That amounts to as many as 150,000 to 260,000 extinct species.
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