Earth.com
06-04-2020

Humans could wipe out billions of years of evolution among vertebrates

Humans could wipe out billions of years of evolution among vertebrates. For the first time, researchers have mapped the evolutionary history of terrestrial vertebrates, including mammals, birds, reptiles, and amphibians.

The study was designed to pinpoint regions where the world’s evolutionarily distinct species are the most threatened by human activities. 

Study co-author Shai Meiri is a professor in the School of Zoology at Tel Aviv University.

“Being ‘evolutionarily distinct’ means that you have no close living relatives,” said Professor Meiri. “In other words, you are alone on your branch of the evolutionary tree of life.”

“Aardvarks, crocodiles, and kiwis were all separated from their closest evolutionary relatives tens of millions of years ago and bear a unique evolutionary history.

“The new research will provide a clear understanding of how best to protect nature given the current threats to specific locations and endangered species.”

The researchers developed two new metrics to investigate the extent of human pressure across the spatial distribution of species. For reptiles, in particular, the team found that regions under the most pressure contain the highest diversity. 

“Our analyses reveal the incomprehensible scale of the losses we face if we don’t work harder to save global biodiversity,” said study lead author Dr. Rikki Gumbs of the Zoological Society of London.

“To put some of the numbers into perspective, reptiles alone stand to lose at least 13 billion years of unique evolutionary history, roughly the same number of years as have passed since the beginning of the entire universe.”

After analyzing the extinction threats for around 25,000 species, the researchers found that at least 50 billion years of evolutionary heritage are at risk of being erased by human activities. 

The areas that host the most unique evolutionary history, such as the Caribbean and large parts of Southeast Asia, are facing intense human pressure.

“This new study highlights which species should be prioritized for conservation, based on their evolutionary uniqueness and the intense human impact on environments where they are thought to dwell,” said Professor Meiri.

According to the study authors, the greatest losses of evolutionary history will result from the extinction of entire groups of closely-related species, such as pangolins and tapirs, and by the disappearance of highly evolutionarily distinct species, such as the ancient Chinese crocodile lizard, the Shoebill, and the Aye-aye – a nocturnal lemur with big yellow eyes and long fingers.

The study identified several unique species that require urgent attention, including the punk-haired Mary River turtle, the Purple frog, and the Numbat. 

For more than half of the priority lizards and snakes identified in the study, extinction risk data was found to be insufficient.

“These are some of the most incredible and overlooked animals on Planet Earth,” said Dr. Gumbs. “From legless lizards and tiny blind snakes to pink worm-like amphibians called caecilians, we know precious little about these fascinating creatures, many of which may be sliding silently toward extinction.”

Across the Amazon rainforest, the highlands of Borneo, and parts of southern Africa, the experts discovered some areas where unique species are essentially unaffected by human pressure.

“Our findings highlight the importance of acting urgently to conserve these extraordinary species and the remaining habitat that they occupy – in the face of intense human pressures,” said study co-author Dr. James Rosindell.

The study is published in the journal Nature Communications.

By Chrissy Sexton, Earth.com Staff Writer

 

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