140,000 plant species face extinction

Two-fifths of the world’s plant species are at risk of extinction, according to a global assessment by the Royal Botanic Gardens Kew in London.

Royal Botanic Gardens Kew in London.

Two-fifths of the world’s plant species are at risk of extinction, according to a global assessment by the Royal Botanic Gardens Kew in London.

Scientists said species that could be valuable sources of medicine and food were disappearing before they could be identified, caused mainly by agriculture, unsustainable harvesting and dams and other infrastructure.

The State of the World’s Plants and Fungi 2020 report, by 210 scientists from 42 countries, estimated 140,000 species, or 39.4 per cent, of plants were threatened with extinction, up from 21 per cent in a similar review by Kew in 2016. Kew said the increase was due more to better analysis of the extent of risk than a rise in threats.

The researchers used higher resolution data on forest loss and other land use changes to determine the likely impact on the distribution of species.

They also accounted for bias in how species had been selected for previous assessments that had resulted in risks being under-reported in some less studied areas and plant groups.

More than 723 plants used for medicine were found to be at risk of extinction, including Brugmansia sanguinea from South America, traditionally used for circu­latory disorders and which has disappeared from the wild.

Other medicinal species at risk of extinction include Nepenthes khasiana from India, used for skin diseases, and the black pepper-bark tree from Africa, a traditional medicine for coughs and colds.

Critically endangered British plants include fen violet, restricted to a handful of sites in ­Cambridgeshire and Oxfordshire, and least waterlily, which in Eng­land is found only in Colemere, Shropshire.

However, the report said 1942 plant species and 1886 fungi were discovered last year.

They include new plants related to species that treat inflammation and malaria, as well as wild relatives of spinach, cassava and sweet potato, and eight new species of fungi.

The Times