A fifth of the world's plant species are at risk of extinction, British researchers warned in an unprecedented global census of the plant kingdom. The survey by Britain's Royal Botanic Gardens at Kew, London, said 21 percent of species are under threat. The report, the first of its kind, is intended to become a global reference point for the study of plants.
The study, which estimates there are a total of 390,900 plants known to science, found farming to be the biggest extinction threat, representing 31 percent of the total risk to plants. Logging and the gathering of plants followed at 21.3 percent, with construction work attributing for 12.8 percent of the risk. The threat of climate change and severe weather was estimated at making up 3.96 percent, although scientists said it may be too early to measure the long-term effects.
Other threats came from invasive species, dam-building and fires. "There has never been a State of the World's Plants," said Kathy Willis, director of science at Kew, which has one of the world's largest plant collections in its sprawling greenhouses and gardens.
The report said that some 1,771 areas of the world have been identified as "important plant areas" but very few have conservation protection measures in place. It also said that 2,034 vascular plants -- which exclude mosses and algae -- were discovered last year alone, including an insect-eating sundew, a new type of onion and a giant slipper orchid. Most new finds are in Australia, Brazil or China. Some 17,810 plant species have a medical use, 5,538 are eaten, 3,649 become animal feed and 1,621 are used for fuels, the report said.
The report will be published annually and Kew Gardens hopes it will allow for comparisons on preserving the world's plants.
But raising public awareness can be more complicated than warning about threats to African elephants or Bengal tigers.
The report stressed the importance of collecting samples of "crop wild relatives", cousins of plants used as common crops with traits that could make food plants more resilient to climate change and diseases.
