Plants humans don’t need are on the verge of extinction, study finds | Biodiversity

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Researchers have classified more than 80,000 plant species around the world and found that most of them will ‘lose out’ to humanity – going extinct because people don’t need them.

This means that the plant communities of the future will be vastly more homogenized than those of today, according to the article published in the journal Plants, People, Planet.

The findings, which paint a bleak picture of the threat to biodiversity, cover less than 30% of all known plant species, and as such are a ‘red flag’, say the researchers, stressing the need to continue work in this area. .

“We’re actually starting to quantify what’s going to go through the Anthropocene bottleneck, in terms of numbers,” said John Kress, curator emeritus of botany at the Smithsonian’s National Museum of Natural History and lead author of the item. “It’s not the future, it’s happening. The bottleneck is starting to happen right now. And I think that’s part of the wake-up call that we’re trying to sound here. It’s something we might be able to slow down a bit, but it’s happening.

Researchers at the Smithsonian Institution set out to categorize exactly which plant species have been most impacted by humans since the start of the Anthropocene – the geological epoch marked by profound human impact on Earth, during which Humans have been responsible for global warming, deforestation and the other negative results of industrialization.

Magnolia ekmanii, a critically endangered tree in Haiti, has been harvested for its wood to produce charcoal and building materials. Photography: Martin Reith (CC BY-NC)

They analyzed data on 86,592 species of vascular plants, collating information from international databases on the different uses of these plants: whether as crops, which are economically important to humans, to invasive weed species, endangered species that need to be protected or rare species. who are involved in illegal trade, for example.

From this information, they created a categorization of how plants are doing and will do in the future, outlining eight distinct categories and concluding that many more plant species will be driven to extinction by the activity. human on Earth, rather than helped.

There are 6,749 plants that are winners and useful to humans such as corn, rice, wheat and other crops, which cover 40% of the planet’s surface, and plants that have disappeared in the wild but that survive in cities, like the ginkgo planted in every city block in New York, according to Kress. Then there are 164 plants that are winners and not useful to humans, mostly invasive and weedy species like kudzu, also called “the vine that ate the south”.

About 20,290 species of plants are classified as losers, mainly because they are not useful to humans, and they are already recognized as endangered species – such as the magnolia from Haiti, which has been cut down for wood heating and does not grow anywhere else. Small lineages of plant species – such as cycads, the cypress family like redwoods and junipers, and an ancient family of conifers called araucariales – are most likely to disappear altogether.

Ginkgo biloba, a winning species, has been cultivated by man for hundreds of years and is a popular ornamental tree that has also been used for food, medicine and as a dietary supplement.
Ginkgo biloba, a winning species, has been cultivated by man for hundreds of years and is a popular ornamental tree that has also been used for food, medicine and as a dietary supplement. Photo: Smithsonian Institute courtesy GA Cooper

Scientists have labeled 26,002 species as potential losers and 18,664 species as potential winners. The last two categories are those of plants currently considered neutral and 571 already extinct plant species.

The results suggest that in the future there will be much less biodiversity, leading to a loss of animal diversity and making ecosystems even more vulnerable to extreme weather, climate change or increased degradation due to human impact.

“The authors used a dataset of 86,592, which represents about 25% of the world’s vascular plants,” said Barnabas Daru, assistant professor of biology at Texas A&M University, who was not involved in the study. . “This means that we are missing a large part of the puzzle, especially the vast knowledge gaps in some of the most floristically diverse but poorly sampled regions of the world, such as South America, Africa and Southeast Asia.”

Daru points out that there are other data sets that could help complete the picture and possibly show a different pattern for winners and losers.

With enough effort, any plant can be saved from extinction, said Richard Corlett, a professor at the Xishuangbanna Tropical Botanical Garden, who was not involved in the study – for example, in living collections. , in seed banks or in cryogenic tissue storage. That’s why there should be a louder call for zero plant extinction, Corlett argues, and findings like these should ring alarm bells and spur action.

“How many people can name an endangered plant? Corlett said. “Plant conservation is not like animal conservation, where we continue to lose species despite efforts to save them. In plant conservation, there are no hopeless cases, at least when it comes to extinction.

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