The World's Plants are Going Extinct about 500 Times Faster than they should, Study Finds...
The World's Plants are Going
Extinct about 500 Times Faster than they should, Study Finds.
Seed plants — including most
trees, flowers and fruit-bearing plants — are going extinct about 500 times
faster than they should be, a new study shows.
If you're the sort of person
who just can't keep a plant alive, you're not alone — according to a new study
published June 10 in the journal Nature Ecology &
Evolution, the entire planet seems to be suffering from a similar
affliction.
After analyzing the
populations of more than 330,000 seed-bearing plants around the world, the
study authors found that about three plant species have gone extinct on
Earth every year since 1900 — a rate that's roughly 500 times higher than the
natural extinction rate for those types of plants, which include most trees,
flowers and fruit-bearing plants. Unsurprisingly, human activity plays a key
role in this elevated extinction trend. [Wipe Out: History's Most
Mysterious Extinctions]
"The geographical pattern of modern extinction
of plants is strikingly similar to that for animals," the researchers
wrote in their new study.
The team found that roughly
half of all reported plant extinctions occurred on isolated islands, where
species are more vulnerable to environmental changes brought on by human
activity. The islands of Hawaii proved
the single most dangerous place for plant species, with 79 extinctions reported
there since 1900. Other places with particularly high extinction rates included
the Cape Provinces of South Africa, the island of Mauritius, Australia, Brazil and
India.
To reach these conclusions,
the researchers scoured every journal and plant database at their disposal,
beginning with a 1753 compendium by pioneering botanist Carl Linnaeus and
ending with the regularly updated IUCN Red List of
Threatened Species, which maintains a comprehensive list of endangered and
extinct plants and animals around the world. After combining and cross-checking
the various extinction reports, the team compared the results to the natural or
"background" extinction rates for plants, which a 2014 study calculated to
be between 0.05 and 0.35 extinctions per million species per year.
The researchers found that, while roughly 1,300
seed plant species had been declared extinct since 1753, about half of those
claims were ultimately proven to be false. In the last 250 years, more than 400
plants thought to be extinct have been rediscovered, and 200 others have been
reclassified as a different living species. That leaves approximately 571
species confirmed extinct in the last 250 years, vanishing at a rate of roughly
18 to 26 extinctions per million species per year.
That number may look wilted
when compared with the rate at which animals are dropping off the planet (which
is about 1,000 times greater than
the natural rate), but the trend is still troubling.
Perhaps more troubling, the
authors wrote, is that the elevated extinction rate they found is very likely
an underestimate of the actual number of plant species that are extinct or
critically endangered. These results do not account for plants that are
"functionally extinct," for example; meaning they only exist in
captivity or in vanishingly small numbers in the wild, Jurriaan de Vos, a
phylogeneticist at the University of Basel in Switzerland, who was not involved
in the research, told Nature.com.
(De Vos is, however, the lead author of the 2014 study on background extinction
rates.)
"You can decimate a
population or reduce a population of a thousand down to one and the thing is
still not extinct," de Vos said. "But it doesn’t mean that it’s all
OK."
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