Humans have driven more than 1,400 bird species to extinction, twice as many as previously thought

Since humans began to spread throughout the world, it has caused the extinction of more than 1,400 species of birds. The new figure was published on Tuesday in the journal Communication in Nature is double the previous estimates. The equivalent of 12% of all existing bird species have disappeared. Research has revealed the true scale of both the magnitude of these human-driven extinction waves (due to deforestation, mass hunting and the introduction of invasive species) and their implications for biodiversity.

Since most known bird extinctions have occurred on islands, researchers have used the fossil record to estimate how many species have gone extinct in Fiji, Hawaii, New Zealand, and other islands in the Western Pacific. Therefore, they calculated that 1,430 species of birds worldwide have disappeared since the late Pleistocene (starting 126,000 years ago), with most of these extinctions occurring in the last 11,700 years.

About 55% of these extinctions have not been discovered until now. Previous data has focused on well-documented extinctions, dating back more than 500 years. The research team made up of scientists from the University of Gothenburg (Sweden), the Center for Research in Forest Ecology and Applications in Spain and other universities in Germany, the United Kingdom and Norway believe that this method minimizes the scale of extinction. Because bird remains are more difficult to preserve and knowledge is not the same in different parts of the world, some species may have become extinct before being recorded. Because of this, the researchers involved statistical models to extrapolate the number with data on the fossil remains. Ferran Sayol, doctor of Terrestrial Ecology at the Autonomous University of Barcelona and co-author of the study, explains that humans have pushed more than one out of nine bird species to extinction, and that this has led to severe ecological and evolutionary consequences that are possibly irreversible.

Birds perform various functions such as seed dispersal by toucans, pollination by hummingbirds, or recycling of nutrients from carcasses by vultures. The disappearance of a bird species affects each ecosystem differently, but by losing their roles or functions, it causes the effects of degradation, for example, a plant can no longer disperse its seeds. or pollinate itself; and, therefore, it also became extinct, said Sayol.

Three major mass extinctions

The research has brought to light some of the largest human-driven extinction waves in history. Sayol and his colleagues found that the worst extinction wave occurred in the 14th century, and was linked to the first arrival of humans on islands across the Eastern Pacific (including the Hawaiian Islands). According to a new study, extinction rates during this period were 80 times higher than previously thought. Another extinction wave occurred in the 9th century BC, due to the arrival of people in the Western Pacific. Researchers estimate that the Pacific is responsible for 61% of all bird extinctions; including iconic species such as the high-billed crow and the Sinotos lorikeet.

The study also highlights the extinction wave that has occurred since the mid-18th century. Since then, in addition to increasing deforestation and the spread of invasive species, birds have had to face more human threats such as climate change, intensive agriculture and pollution. It is expected that this wave will be the largest, because up to 700 bird species may disappear in the next hundred years.

Suyol explained that current extinction rates are 80 times faster than the natural extinction rate. While this wave is smaller than previous ones, it is happening at a much faster rate, he said. What usually happens in millions of years happens in a few hundred. If we continue at the current pace, we can reach that level, he said.

Ramn Mart, director of institutional development at the Spanish Society of Ornithology, who was not involved in the study, said the new figures show the severity of man’s footprint on nature.

The authors emphasize the need to intensify conservation efforts to avoid further loss of biodiversity, as the findings highlight the critical situation of birds worldwide and that humans have a responsibility to preserve the diversity. Sayol hopes that by looking at the past and better understanding how many species have disappeared because of humans, try to save those that are still here.

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