Study calls for rethink on 'extinction' criteria set for plants

Scientific findings about biodiversity have never been good, with the World Conservation Union adding an increasing number of plants and animals to its list of threatened species every year.

According to recent estimates, around 20% of flowering plants are currently at risk of extinction—though the exact number is unknown since only a small proportion of plant species has been measured.

Now, however, research conducted in South Africa and the UK 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.

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.

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.

"Our results challenge the application of the same sets of threat criteria across living organisms and across regions". Savolainen said.

"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,” he added.

The research was published recently in PLoS Biology.