Over 25% of flowers on the planet face extinction – threat to our ecosystems.

7/7/2010 Guardian  More than one-in-four of all flowering plants are under threat of extinctionaccording to the latest report to confirm the ongoing destruction of
much of the natural world by human activity.
As a result, many of nature’s most colourful specimens could be lost to the
world before scientists even discover them, claims the research, published today
in the journal Proceedings of the Royal Society B.
The results reflect similar global studies of other species groups by the
International Union for the Conservation of Nature, which estimates that
one-in-five of all mammals, nearly one-in-three amphibians and one-in-eight
birds are vulnerable to being wiped out completely. Later this year the results
of a huge global analysis of all the world’s estimated up to 400,000 plants by
Royal Botanic Gardens, Kew, is due to be published by the IUCN as part of its
ongoing mission to assess the state of all life on Earth.
“[This year] marks the International Year of Biodiversity,” said Stuart Pimm of
Duke University in North Carolina, USA, one of the authors of the report. “The
focus of this celebration has often been on the species we know of, along with
discussions on the unprecedented challenge of conserving this biodiversity in
the face of threats such as habitat loss. However, by asking just how many
species we will lose before they are even discovered, our study has revealed a
figure that is truly alarming.”
The researchers started by carrying out an independent review of how many
flowering plants – which make up most of the plant kingdom – exist. By
considering the rate at which new specimens are being described to science,
adjusted to reflect the growing number of scientists over the years, and
interviewing experts who focus on different groups such as orchids, irises or
grasses, the team calculated that on top of the existing “best estimate” of
352,282 flowering plants there are another 10-20%, or 35,000-70,000, which have
still to be officially discovered.
The second stage was to assess the level of threats from habitat loss due to
clearing land for planting crops or trees, development, or indirect causes such
as falling groundwater levels and pollution.
They started with a study published in the journal Endangered Species Research
in 2008, which estimated that one-in-five known species were vulnerable to
However based on the fact that new species – like recent discoveries – are
likely to be found in “biodiversity hotspots”, where there are huge numbers of
endemic species which are not widely distributed around the world, and a high
level of habitat loss, they estimated that all so-far-undiscovered flowering
plants were also at risk.
“If we take the number of species that are currently known to be threatened, and
add to that those that are yet to be discovered, we can estimate that between
27% and 33% of all flowering plants will be threatened with extinction,” said
David Roberts, one of the co-authors, of the Durrell Institute of Conservation
and Ecology at the University of Kent.
The paper adds: “These estimates are based on immediate threat, and do not
consider further development of destructive factors - including climate
The paper’s third, lead, author was Lucas Joppa of Microsoft
Research in Cambridge.
The warning comes as there is growing international recognition of the value of
the natural world to humans in providing ecosystem services, from flood
protection and medicines to spiritual spaces and enjoyment.
“Plants are the basis for much of life on earth with virtually all other species
depending on them; if you get rid of those you get rid of a lot of the things
above them,” added Roberts.
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