Humans They are driving Global loss of biodiversity and deterioration of the ecosystem. The impacts have led to the loss of hundreds of plant and animal species with an estimated 1 million threatened with extinction today.
But, while the authors of a New study Stress the need for urgent actions to address the current biodiversity crisis, his research indicates that we are not yet witnessing the sixth “mass extinction event” on Earth.
“A recent study suggested that the extinctions of animal genres accelerate rapidly and that these extinctions endanger human survival,” says principal author John Wiens, professor of ecology and evolutionary biology at the University of Arizona in the United States.
“Instead, we discovered that genres extinctions are very rare between plants and animals.
“We argue that the reason why future extinctions should be stopped is not because they threaten humans, but because it is morally incorrect that humans lead to other species to extinction.”
Throughout the history of the planet, life on Earth has persisted despite 5 mass extinction events in which at least 75% of all species were lost during a short geological period.
The first mass extinction eliminated 86% of all species at the end of the Ordovician period about 443 million years ago (MYA). This was followed by the late Devonic, 375 mya, in which 75% of the species disappeared.
The end of the Permian period (around 250 mya) is known as “the great die” with 96% of the lost species. This was followed 50 million years later by the Triassic end (80%). More recently, 76% of all species were extinguished at the end of the Cretaceous period due to a catastrophic asteroid impact 66 mya.
In 2023, a study in Pnas They used data from the International Union for Nature Conservation (IUCN) to document recent extinctions in tetrapod vertebrates, including birds, mammals, amphibians, turtles, lizards and snakes.
He concluded that extinction rates at the gender level in tetrapods “rapidly accelerate” and that these were evidence of a mass extinction event.
Gender is the taxonomic range above species and under the family by classifying life on earth. For example, gender of the dog It includes multiple species such as Gray Wolf, Domestic Dog and Coyote.
The extinction of genres and higher families represents a greater loss of diversity and ecological function than individual species.
But as the authors of the new PLOS BIOLOGY They point out the study: “Tetrapods cover [less than] <2% of all known species, and only approximately half of the species of known vertebrates. ”
They reviewed data on more than 22,000 vegetable and animal genres evaluated by IUCN to have a better idea of the severity of modern higher level extinctions. The analysis found that recent extinctions were relatively rare, with 102 known since 1500. Among these 79 genera had contained only 1 species.
Genres extinctions occurred in less than 2% of birds and mammals, approximately 1% in turtles and less than 0.5% of the genera evaluated in most others.
The highest extinction rates occurred at the end of 1800 and early 1900.
“They were mostly of genres found only in islands, and … these extinctions actually slowed in the last 100 years instead of rapidly accelerating,” adds Wiens.
The authors suggest that several factors may have contributed to this pattern, including the fact that most gender extinctions occurred in birds and mammals in which “the conservation action has proven to demonstrate the extinctions.”
“There was never evidence that these extinctions, which reached their maximum point [about] ~ 100 years ago and occurred mainly in isolated islands, endangers human survival, ”says Wiens.
The Kristen Saban co -author of Harvard University in the United States adds: “Now more than ever, given the general distrust in science, it is important that we carry out conservation research with care and present with precision.”
The authors warn that their study should not be interpreted as current threats for biodiversity and stress that there may be many additional extinctions at the gender level in the future.
“However, it is not clear if the past extinctions described here are relevant to predict these future extinctions. After all, most of these past extinctions at gender level were on islands and occurred many decades ago,” they write.
“For example, climate change can be an important cause of future extinctions, but it is not an important cause of recent past extinctions or current threats mentioned by IUCN among species.
“Similarly, invasive species were the main cause of most species extinctions in the islands, but habitat loss is the largest current threat for species currently endangered, both in islands and in the continent.”
Human -related extinctions should be prevented, they conclude, regardless of whether they affect the directly beneficial species for humans or are part of a mass extinction event.
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