Global: How many plants out there need saving?


A very interesting article (free access) appeared today in Proceedings of Royal Society B. Carrying the title "How many species of flowering plants are there?" the content wasn't exactly what I was expecting.

image of view over rainforest

How many plants are left to be discovered?

Juliette Jowitt, in The Guardian, who has recently written some great stuff for the newspaper on the need for conservation, hooked her story "Over 25% of flowers face extinction - many before they are even discovered" on the very last paragraph of the article, which read: "Brummit et al. (2008) suggest that 20 per cent of known plant species are threatened. If we take this estimate, then add to that our result that there are 10 to 20 per cent more unknown species that are also likely to be threatened, then 27 to 33 per cent of all plant species are probably threatened."

In truth the article is nothing about the headline that appeared in The Guardian, but strangely it wasn't really about the question that made me so curious initially. At no point do the authors tell us how many species of flowering plants they think there are, though they do tell us that the number could "grow by between 10 and 20 per cent". Should be simple enough, right? However, it's not quite clear which figure this growth is based on. Paton et al (2008) estimated 352,282 unique flowering plants, and this is the only figure offered in the article, so it's reasonable to assume this is the baseline figure upon which the 10 - 20 per cent growth can be added.

The reality, which the article beautifully explores with fishing analogies, such as "the rate taxonomists catch new species", is that there is much uncertainty and guesswork in calculating the global plant wealth (and health). Elements that are explored by the researchers are "taxonomic effort", which simply means the increasing number of taxonomists working on describing new species (and how this relates to the actual number of new species), and garnering "expert opinion" on certain families - by asking them to estimate how many new species in their pet families may await description.

In conclusion - the answer to the question the article poses "How many species of flowering plants are there?" is... a lot. It is also clear that many of these are under significant threat, and may indeed disappear before they take their place in the scientific record. Especially as a vast majority of new species are found in Biodiversity Hotspots, which classically, and by definition, suffer from habitat destruction. To compound this further it is also common knowledge that taxonomy and conservation are severely under-resourced arenas. So the question the article really poses is one of the proverbial chicken and egg...

Do we need to spend more time and money looking for things before they disappear, or do we invest heavily in protection and worry about the details, such as the actual number of global flowering plants, later?

Related links:

Launch of Global Biodiversity Outlook (GB0-3)


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Global: Failing biodiversity targets


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Global: IUCN warns of 'extinction crisis'


Yesterday saw the launch of the International Year of Biodiversity in Berlin, which has the aim of celebrating all life on earth and the value of nature's riches for our lives.

Copenhagen: Nature has the solutions


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