One in five plant species at risk
30 September 2010
A major study of the world’s plant life has revealed that about 20% of known plant species are under threat, leaving plants more vulnerable to habitat loss and other pressures than mammals or birds.
As the 2010 International Year of Biodiversity draws to a close, a four-year analysis of the world’s 380,000 known plant species, carried out by a team of international scientists and published by the International Union for the Conservation of Nature (IUCN), has painted the clearest picture yet of the state of the planet’s plants.
‘It’s like a global barometer, giving some idea of the pressure plants are under,’ said team member Steve Bachman, of the Royal Botanic Gardens, Kew. ‘For the first time we have a real picture of what’s happening to plants across the world.’
The team used the IUCN’s Red List to select species at random, from Vicia faba (broad bean) to rarities like white-flowered Caliphruria hartwegiana, related to amaryllis and found only in Columbia. Then using herbarium specimens and field evidence the team assessed the current level of threat to each species, giving a snapshot of the world’s plant populations against which future rates of loss can be measured.
As a result, some plants have now been identified as extinct for the first time, while others, such as Galanthus nivalis (snowdrop) were revealed to be more threatened than previously thought.
The proportion of all plants at risk of extinction is probably even higher, however. According to a further study published in a Royal Society journal the number of undiscovered plants amounts to 10-20% of those we know about - up to 75,000 species in all. Since most are likely to grow in biodiversity hotspots, the report says, they too could die out before we even know of their existence.
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