A fifth of world's plants are endangered: Study

One in five of the world's 380,000 plant species is threatened with extinction, and human activity is doing most of the damage, according to a global study.

Scientists from Britain's Royal Botanic Gardens at Kew, London's Natural History Museum, and the International Union for the Conservation of Nature (IUCN) found that more than 22% of species were endangered, critically endangered, or vulnerable.

"The greatest threat is conversion of natural habitats to agricultural use, directly impacting 33% of the threatened species," the authors wrote.

The findings were released ahead of a United Nations summit scheduled for mid-October in Nagoya, Japan.

"We cannot sit back and watch plant species disappear — plants are the basis of all life on earth, providing clean air, water, food and fuel. Animal and bird life depends on them totally and so do we," said Stephen Hopper, 14th director of the Royal Botanic Gardens.

The scientists used data analysed in a five-year study to draw up a ‘Sampled Red List Index for Plants’ which will be added to a series of IUCN ‘Red Lists’, designed to help monitor the changing status of the world's major groups of plants, fungi and animals.

As this was the first time a global analysis on the threat to the world's plants had been undertaken, the scientists said it would serve as a baseline to measure conservation efforts.

The study found that agriculture, development, logging, and using land for livestock were among the main reasons for plant species being threatened.                                          

The worst-hit areas were tropical forests such as rainforests in Brazil.

"Present day human activities are pushing more plants towards extinction, but if the world's governments take the right steps we do have the potential to safeguard plant life and the creatures that depend on it," said Steve Bachman, a plant conservation analyst at Kew.

The study included 7,000 plant species drawn from five major groups.

Both common and rare plants species were assessed, to try to give an accurate picture of how plants were faring around the world, the scientists said at a briefing for reporters.

Researchers studied a random sample of about 1,500 species from each group, since assessing the threat to the world's estimated 380,000 plant species would be an enormous task, they said.                                           

By comparing to the vast plant world, experts estimated that there are about 10,000 species of birds, 5,500 species of mammals and 6,300 species of amphibians who are at risk.

"The diversity of plants underpins all life on earth, so it is sobering that our own species is threatening the survival of many thousands of plant species," said Neil Brummitt, a botanical diversity researcher at the Natural History Museum.

"We have set the baseline. Now we all need to work together to safeguard not only the future of plants but the future of ourselves."