Humanity’s ongoing annihilation of wildlife is cutting down the tree of life, including the branch we are sitting on, a new analysis shows.
More than 300 mammal species have been eradicated by human activities, the researchers said.
The authors calculated the total unique evolutionary history that has been lost as a result at 2.5 billion years.
Illustration: Mountain people
Even if the destruction of wild areas, poaching and pollution were ended within 50 years and extinction rates fell back to natural levels, it would still take 5 million to 7 million years for the natural world to recover, they said.
Many scientists think a sixth mass extinction of life on Earth has begun, propelled by human destruction of wildlife, and 83 percent of wild mammals have already gone.
The new work puts this in the context of the evolution and extinction of species that occurred for billions of years before modern humans arrived.
“We are doing something that will last millions of years beyond us,” said Matt Davis at Aarhus University in Denmark, who led the new research. “It shows the severity of what we are in right now. We’re entering what could be an extinction on the scale of what killed the dinosaurs.
“That is pretty scary. We are starting to cut down the whole tree [of life], including the branch we are sitting on right now,” Davis said.
Ecosystems around the world have already been significantly affected by the extermination of big animals, such as mammoths, he said.
The research, published in the Proceedings of the National Academy of Sciences, did not simply add up the number of lost species, as this fails to capture how unique each species is in evolutionary terms.
Instead, the researchers added up the amount of time each lost species had spent evolving since it emerged, a measure called phylogenetic diversity.
There are hundreds of species of shrew, for example, but just two species of elephant, Davis said, adding that losing elephants would therefore be like chopping a large branch off the tree of life, whereas losing a shrew species would be like trimming off a small twig.
From the rise of modern humans to the year 1500, 2 billion years of evolutionary history was lost due to mammal extinctions, the researchers calculated, adding that since 1500, another 500 million years have been lost.
If the current high rate of extinctions continues for 50 years, a further 1.8 billion years of phylogenetic diversity could disappear, they said.
There are still many mammal species left, but all of these would have to evolve for 5 million to 7 million years into the future to get back to the level of diversity present before modern humans arrived, the researchers estimated.
Davis said each lost species had its own intrinsic value, but the loss of the most distinct creatures was most damaging.
“Typically, if you have something that is off by itself, it does some job that no other species is doing,” he said.
The losses are already affecting ecosystems, particularly the vanishing of “megafauna,” he said.
These huge creatures roamed much of Earth until humans arrived and included giant cats, deer, beavers and armadillos.
“We are now living in a world without giants,” Davis said. “So the seeds of big fruit are not dispersed anymore because we don’t have mammoths or Gomphotheres or giant ground sloths eating those fruits.”
Another example is the widespread loss of wolves, which means that smaller predators like coyotes thrive and more birds are killed, radically changing food chains, Davis said.
He said the estimated recovery times for phylogenetic diversity are conservative.
“We have no reason to assume we will ever be able to bring extinction rates back down to normal background levels,” he said.
The team only looked at mammals, as they are well studied, but extinctions among other animals are just as high.
The new work did allow the researchers to identify highly endangered species with long evolutionary histories, Davis said.
“This highlights species we should try to save and could help us prioritize conservation,” he said.
The black rhino, the red panda and the indri — a large lemur — are among those highlighted.
“They have made a dramatic and convincing statement of how much evolutionary diversity has already been lost,” said Douglas Futuyma at Stony Brook University on Long Island, New York, who was not part of the research team. “The most important point is one that I believe is already widely recognized: Humans are extinguishing not only many species, but many kinds of species.”
He said that while overall evolutionary distinctiveness can be recovered over time, particular species — such as elephants — would never re-evolve if lost.
“We are not merely trimming the terminal twigs of the tree of life, we are lopping off entire limbs,” said Stuart Pimm at Duke University in North Carolina, adding that the research used better data than earlier work.
However, prioritizing distinctive species would be hard in practice, as it is usually overall habitats that are protected, he said.
“There’s a lot of armchair conservationists out there,” he said.
The past few months have seen tremendous strides in India’s journey to develop a vibrant semiconductor and electronics ecosystem. The nation’s established prowess in information technology (IT) has earned it much-needed revenue and prestige across the globe. Now, through the convergence of engineering talent, supportive government policies, an expanding market and technologically adaptive entrepreneurship, India is striving to become part of global electronics and semiconductor supply chains. Indian Prime Minister Narendra Modi’s Vision of “Make in India” and “Design in India” has been the guiding force behind the government’s incentive schemes that span skilling, design, fabrication, assembly, testing and packaging, and
Singaporean Prime Minister Lee Hsien Loong’s (李顯龍) decision to step down after 19 years and hand power to his deputy, Lawrence Wong (黃循財), on May 15 was expected — though, perhaps, not so soon. Most political analysts had been eyeing an end-of-year handover, to ensure more time for Wong to study and shadow the role, ahead of general elections that must be called by November next year. Wong — who is currently both deputy prime minister and minister of finance — would need a combination of fresh ideas, wisdom and experience as he writes the nation’s next chapter. The world that
Recently, China launched another diplomatic offensive against Taiwan, improperly linking its “one China principle” with UN General Assembly Resolution 2758 to constrain Taiwan’s diplomatic space. After Taiwan’s presidential election on Jan. 13, China persuaded Nauru to sever diplomatic ties with Taiwan. Nauru cited Resolution 2758 in its declaration of the diplomatic break. Subsequently, during the WHO Executive Board meeting that month, Beijing rallied countries including Venezuela, Zimbabwe, Belarus, Egypt, Nicaragua, Sri Lanka, Laos, Russia, Syria and Pakistan to reiterate the “one China principle” in their statements, and assert that “Resolution 2758 has settled the status of Taiwan” to hinder Taiwan’s
As former president Ma Ying-jeou (馬英九) wrapped up his visit to the People’s Republic of China, he received his share of attention. Certainly, the trip must be seen within the full context of Ma’s life, that is, his eight-year presidency, the Sunflower movement and his failed Economic Cooperation Framework Agreement, as well as his eight years as Taipei mayor with its posturing, accusations of money laundering, and ups and downs. Through all that, basic questions stand out: “What drives Ma? What is his end game?” Having observed and commented on Ma for decades, it is all ironically reminiscent of former US president Harry