One in five types of plant worldwide is at risk of extinction from threats such as farming and logging that are wrecking many habitats, a first global overview of plant life said on Tuesday.
In total, 391 000 types of plants are known to science, from tiny orchids to giant sequoia trees, according to the report State of the World’s Plants written by 80 specialists led by the Royal Botanic Gardens (RBG) at Kew, in London.
And despite 21% of all the species being threatened with extinction, the report said new plants were still being discovered, such as a 1.5m tall insect-eating plant on a mountaintop in Brazil in 2015. In fact, about 2 000 new types of plant are still being described every year.
Nonetheless, the experts said many parts of the world were suffering rapid change, such as from the felling of tropical forests to make way for farms and cities. Global warming was among other man-made risks.
“There’s a huge change going on, mainly agricultural change and land for urbanisation,” said Kathy Willis, RBG Kew’s director of science. The report, meant as a first annual audit of the world’s plants, omits plants such as algae and mosses.
Willis said a rising world population of more than seven billion people needed food and places to live and that scientists should be pragmatic and help identify areas most in need of conservation.
The study said 31 000 plant species had documented uses such as in medicines, food or building materials. Little-known plants might have unknown benefits, such as resilience to diseases.
“If we completely clear the land and have a type of monoculture, what happens when a new plant disease emerges and wipes out the crop entirely?” asked Steve Bachman, a species conservation researcher at RBG.