The first-ever report analysing the state of the world's plants says more effort is needed to assess species at risk of extinction and to develop policies to combat the problem.
Some 21% of plant species are at risk of extinction, according to the State of the World’s Plants report published this week by Kew, the Royal Botanic Gardens.
The figure is Kew’s ‘best estimate’ since just 5% of vascular plant species have undergone threat assessments. It is far lower than previous estimates, which have ranged from 10%–62%, but the report says it still shows the urgent need to act.
Agricultural intensification and land-use change are the biggest potential causes of extinction – threatening some 31% of at-risk species. Climate change is surprisingly only the main threat for 3.96% of species. However, the report says there is ‘an urgent need to understand the responses of the world’s plants to climate change at a number of different levels, ranging from genes and species to communities and ecosystems.’ Species would either have to genetically adapt to cope with climate change or migrate otherwise they face extinction. There is already evidence of all three outcomes occurring.
Kew’s report is the first baseline assessment of global plant life. ‘With this, we hope to raise the profile of plants and highlight not only what we do know about threats, status and uses, but also what we don’t,’ said director of science Professor Kathy Willis. ‘This will help us to decide where more research effort and policy focus is required to preserve and enhance the essential role of plants in underpinning all aspects of human wellbeing.’
There are 391,900 vascular plant species, of which 369,400 are flowering, Kew estimates. This is based on an analysis of databases used to name plants, many of which overlap.
Roughly 2,000 new species have been found every year for the past decade, the report adds. Several of the species identified in 2015 are already presumed extinct, illustrating the extent of threat facing plants. A new tree species in Ghana and the Ivory Coast, for example, is now assumed extinct as its dry forest habitat has either been cleared for agriculture or destroyed by fire. Similarly, a herb specific to waterfalls has been destroyed after its only known habitat was used as the site for a hydroelectric dam.
Some 1,771 ‘important plant areas’ have been identified around the world, the report says. These are an internationally recognised areas identified as either being particularly rich in biodiversity or containing threatened species and habitats. In the UK, they include the Lizard in Cornwall and the Brecklands in East Anglia. However, just 69 countries have undertaken assessments for such areas and report states that ‘a clear gap remains in the tropics’. Earlier this year Kew launched programmes to identify areas in seven countries and regions including Guinea, Cameroon, Bolivia and Mozambique.
So far, there has also only been a limited political response to protect these areas and the report makes a strong call for action since ’many are degrading or disappearing under the assault of land-use change, climate change, pests and diseases.’
The report is weakest in its analysis of policy, since it focuses on just two: the Convention on International Trade in Endangered Species (CITES), which tries to prevent trade in illegal timber and rare plants such as orchids; and the Nagoya Protocol on Access to Genetic Resources and Benefit Sharing, which was developed to ensure countries are paid for commercial exploitation of their plant resources so promoting greater efforts to protect biodiversity.
However, supplementary material available on the policy section of the report’s website includes links to others policies that focus on plants, such as the EU’s biodiversity regulations, as well as a list of scientific papers that offer more in-depth commentary.
The report will be revised each year, Kew says, so its policy focus is likely to quickly improve.
