3 in 4 undiscovered plant species and 45 per cent of known flowering plants are already threatened with extinction, new research by Kew finds
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With the majestic Victorian greenhouses gleaming in the October sun and grounds planted with thousands of rare plant species, Kew Gardens offered a visually stunning backdrop to its triennial ‘State of the World’s Plant and Fungi’ symposium this week.
But the contents of this year’s report, published last week, offered an altogether darker outlook on the world of botanicals. Scientists are increasingly battling the clock when it comes to discovering and protecting global plant species.
Combining the research of more than 200 scientists from 102 different institutions, the report found that 45 per cent of known flowering plants are already threatened with extinction. Some of the most at-risk plant families are orchids, Piperaceae, which includes black pepper and Bromeliaceae, which includes pineapple.
Research also indicates that 77 per cent of undiscovered plant species are likely to be threatened with extinction. Though there are already 350,000 plants known to science, an estimated 100,000 are still to be named and classified, leaving fears that many could be lost before they are found.
‘The news for plants is pretty bleak,’ Dr Bill Baker, a taxonomist for the Royal Botanical Garden Kew (RBG), told Geographical. He described the report, which is part of an ongoing series to track the progress of research and conservation efforts, as a ‘health check’ for the world’s plants and fungi. But it also functions as a ‘call to action’ and guide for policymakers and conservationists.
The reason newly discovered plants are at such high risk is because they tend to be confined to very small geographical areas. At the same time, they are undergoing a continuous decline as a result of factors like climate change and species homogenization (where a small number of species begin to dominate broad swathes of the world).
This lethal combination means each year, a higher proportion of discovered plants is classified as threatened. In 2020, the proportion hit 77 per cent and the number is predicted to continue rising.
Dr Matilda Brown, a conservation researcher for RBG, noted that because the process of ‘describing’ often takes months or years, some plants even go extinct before they are officially classed as at risk. She gave the example of the so-called ‘orchid of the falls’. First discovered in 2018 in a waterfall in Guinea in West Africa, it was only officially described in 2022. But by that time, its only known location had been flooded because a dam had been constructed downstream.
‘This species is almost certainly extinct and was very probably extinct before it was even described,’ she told Geographical. Dr Brown is one of a number of Kew scientists calling for all newly described species to be treated as though they have been assessed as threatened unless proven otherwise.
‘If we treat something as if it’s threatened from the moment that we know about it, then it allows us to put in place interim conservation actions while we go through the process of getting it assessed,’ she explained.
These plants are worth protecting, she noted, because of the ‘opportunity loss’ that comes with every extinction.
‘From a human-centred perspective, we don’t know what the natural benefits to humanity we’re losing. We’re finding that some of the most recently discovered plants have immediate benefits to humanity,’ she said.
A member of the citrus family, the Vepris onanae from the cloud forests in Cameroon, was described in 2022. It is currently being researched for its antimicrobial properties – and has been classified as critically endangered.
‘Everybody depends on plants,’ Dr Baker noted. ‘Whether you’re eating a meat or plant-based diet, it is ultimately derived from plants, most materials come from plants, the majority of our medicines are from plants and fungi.’
The RBG report was not all doom and gloom. More than 18,800 new plant and fungi species have been discovered and named since 2020. And a monumental new ‘World Checklist of Vascular Plants’, a 35-year project to compile a database of every known vascular plant species on the planet will enable unprecedented research projects and knowledge sharing between scientific communities.
Chapters also highlighted the groundbreaking research happening in the world of fungi. Scientists have only discovered 10 per cent of the estimated 2.5 million species, with the field presenting a new ‘frontier of discovery’.
But the report is also clear: decision-makers need to take immediate action when it comes to protecting plants and fungi. Beyond saving individual species from extinction, conservation is necessary to support whole interlocking systems of biodiversity and restore vulnerable habitats.
‘Now is the time that we have to act to conserve plants,’ Dr Brown said. ‘We can’t wait until we’ve described them all. We can’t wait until we have all the knowledge. We need to act now. There’s always more research to do. But research alone isn’t going to be enough to tackle the nature of urgency.’
