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Rethinking extinction risk? Criteria for assessing risk of extinction in plants should be reconsidered, experts argue

Date:
May 24, 2011
Source:
Public Library of Science
Summary:
For over 40 years, the International Union for Conservation of Nature has published the Red List of Threatened Species describing the conservation status of various species of animals. They're now also including plants in their lists and the picture they present is dramatic: according to recent estimates, around 20 percent of flowering plants are at risk of extinction. Now, however, new research suggests that the criteria for assessing extinction risk in plants should be reconsidered.
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For more than 40 years, the International Union for Conservation of Nature (IUCN) has published the Red List of Threatened Species describing the conservation status of various species of animals. They are now also including plants in their lists and the picture they present is dramatic. According to recent estimates, around 20 per cent of flowering plants are currently at risk of extinction -- though the exact number is unknown since such a small proportion of plant species has even been measured.

Now, however, research conducted in South Africa and the U.K. by an international team of researchers, led by McGill biologist Jonathan Davies and Vincent Savolainen from Imperial College London and Kew Gardens, suggests that the criteria for assessing risk of extinction in plants should be reconsidered. "Reducing rates of extinction represents one of the greatest ecological challenges of our time," Davies said, "but identifying which species are most at risk can be difficult." The research is published on May 24th in PLoS Biology.

By some criteria, a species is considered at risk if it is to be found only in a limited geographical range and if it has a small population size. But through molecular analysis of DNA sequences from plant specimens in the Cape region in South Africa, an area known for its spectacular plant diversity, the researchers have been able to show that these criteria also describe species that are relatively new arrivals. "In plants, from this area, we show that the processes of extinction and speciation [the evolutionary process by which new species arise] are linked -- seemingly the most vulnerable species are often the youngest. Young species may appear at high risk of extinction simply because their populations have not yet had time to grow and spread. However, it is also possible that some plant species might be doomed to extinction from their very inception," Davies said.

They also show that the pattern of threat in the Cape differs from that for plants in the more temperate UK and from that seen for vertebrates. Deciding which species should have the highest priority for conservation is a fraught process, Savolainen suggests. "Our results challenge the application of the same sets of threat criteria across living organisms and across regions." Savolainen added: "We may need to think of ways to fine tune the implementation of 'Red List' criteria for rapid assessments of threat -- a daunting task that might prove even more pressing given the changes we see in our global environment."


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The above post is reprinted from materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. Jonathan Davies, Gideon F. Smith, Dirk U. Bellstedt, James S. Boatwright, Benny Bytebier, Richard M. Cowling, Félix Forest, Luke J. Harmon, A. Muthama Muasya, Brian D. Schrire, Yolande Steenkamp, Michelle van der Bank, Vincent Savolainen. Extinction Risk and Diversification Are Linked in a Plant Biodiversity Hotspot. PLoS Biology, 2011; 9 (5): e1000620 DOI: 10.1371/journal.pbio.1000620

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Public Library of Science. "Rethinking extinction risk? Criteria for assessing risk of extinction in plants should be reconsidered, experts argue." ScienceDaily. ScienceDaily, 24 May 2011. <www.sciencedaily.com/releases/2011/05/110524171249.htm>.
Public Library of Science. (2011, May 24). Rethinking extinction risk? Criteria for assessing risk of extinction in plants should be reconsidered, experts argue. ScienceDaily. Retrieved July 30, 2015 from www.sciencedaily.com/releases/2011/05/110524171249.htm
Public Library of Science. "Rethinking extinction risk? Criteria for assessing risk of extinction in plants should be reconsidered, experts argue." ScienceDaily. www.sciencedaily.com/releases/2011/05/110524171249.htm (accessed July 30, 2015).

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