One-fifth of the world’s plants are at risk of extinction, according to scientists from Kew who have conducted a major study before governments meet to set new targets at the United Nations Biodiversity Summit in Nagoya, Japan, on October 18-29.

This is the first time the true extent of the threat to the world’s 380,000 plant species has been revealed, as the landmark survey was carried out on random plants rather than just ones that were known to be at risk. ‘For the first time, we have a clear global picture of extinction risk to the world’s known plants,’ explains Kew director Prof Stephen Hopper.

‘Our Sampled Red List Index for Plants shows the most urgent threats and the most threatened regions. In order to answer crucial questions like how fast we are losing species and why, and what we can do about it, we need to establish a baseline so that we have something against which to measure change.’
 
He adds, ‘The significance of plants in uncertain climatic, economic and political times has been overlooked for far too long. We cannot sit back and watch species disappear-plants are the basis of all life on earth, providing clean air, water, food and fuel.’  

Defra minister Caroline Spelman described the news as ‘deeply disturbing’. Although the most threatened species are found in the tropics, the largest perceived threat is man-made destruction of habitat. In Britain, the wood bitter vetch (Vicia orobus), which likes woodland and field margins and rocky places, is considered to be of concern and is protected in Ireland.

The study took a random 1,500 species from each of the five major plant groups: mosses and liverworts, land plants that do not flower or seed, gymnosperms (such as conifers), monocotyledons (flowering plants, including orchids) and legumes.

However, the process revealed that some species are so poorly-known that it is impossible to assess their status, which demonstrates the scale of the problem facing botanists-funding is badly needed.