“Strange and wonderful” animals, which look like nothing else on Earth, are silently sliding to extinction, they say.
And the regions with the largest amounts of unique biodiversity face unprecedented human pressures.
They include the Caribbean, the Western Ghats of India and large parts of Southeast Asia.
The study, published in Nature Communications, highlights priority species for conservation, based on their evolutionary distinctiveness.
“These species are strange and wonderful and there is nothing like it on Earth,” said Rikki Gumbs of ZSL’s EDGE of Existence program and Imperial College London.
He said the analysis reveals “the incomprehensible magnitude of the losses we face if we don’t work harder to save the world’s biodiversity.”
Researchers calculated the amount of evolutionary history – branches on the tree of life – that are currently threatened with extinction, using data on the risk of extinction for more than 25,000 species.
They discovered that at least 50 billion combined years of evolutionary heritage were threatened by human impacts such as urban development, deforestation and road construction.
Rikki Gumbs said that numbers are very important because species evolve in parallel; for reptiles alone, you get a figure of 13 billion years (about the age of the Universe).
He said, “The tree of life is so vast and the extinction is so widespread in the tree of life that when you start adding up all of these numbers, you end up with this kind of incomprehensible numbers over 50 billion years. “
Animals at risk include tapirs and pangolins, which have ancient lines and have changed little over time; and fascinating little-known reptiles, legeless lizards to tiny blind snakes.
Many perform vital functions in the habitats in which they live. For example, tapirs in the Amazon disperse seeds in their droppings, which can help regenerate the rainforest. And pangolins, who are specialized eaters of ants and insects, play a vital role in balancing the food web.
Co-investigator Dr James Rosindell of Imperial College London, UK, said the results underscore the importance of urgent action to conserve these extraordinary species and the remaining habitat they occupy, “in the face of intense human pressure”.
New targets for the protection of the natural world are expected to be agreed in October during what was to be a critical year for nature.
Conservation groups say the pandemic has disrupted conservation work and funding, with potential repercussions for years to come, but we can take the opportunity to push for stronger action to protect the natural world.
Last year, an intergovernmental group of scientists declared that one million animal and plant species are now threatened with extinction.
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