Rapidly Vanishing Species Could Lead To Earth's 'Sixth Great Extinction'
RedOrbit - 19 hours ago
May 31, 2014

Image Caption: Okapi have been undergoing a decline since at least
1995 that is ongoing and projected to continue, in the face of severe,
intensifying threats and lack of effective conservation action.
Credit: Thinkstock.com
redOrbit Staff & Wire Reports – Your Universe Online
Plant and animal species are becoming extinct at rates more than 1,000
times more quickly than they did before the arrival of humans,
indicating that the Earth could be edging closer to a sixth great
extinction, according to a new study published May 30 in the journal
Science.
In the study, Duke University biologist Stuart Pimm and his colleagues
examined both past and present rates of extinction using the IUCN Red
List of Threatened Species and related resources. While performing
their review, the researchers discovered that the historical
extinction rate was lower than scientists had originally believed.
As a result of their investigation, Pimm told Associated Press (AP)
Science Writer Seth Borenstein that his team now believes that species
are dying out globally approximately 10 times more quickly than
biologists had believed. Pimm added that the planet is "on the verge
of the sixth extinction," and that whether or not it can be avoided
"will depend on our actions."
The new research, which Borenstein said is being hailed as a landmark
study by the scientific community, focuses specifically on the
extinction rate and not the actual number of species vanishing from
the planet. The authors calculated a "death rate" of species that
become extinct annually out of one million unique species.
"Calculating extinction rates can be difficult, in part because no one
knows exactly how many species there are," explained Christine
Dell'Amore of National Geographic. Experts have managed to identify at
least 1.9 million animal species, and the study reported that there
are at least 450,000 types of plants in existence, she added.
Pimm told Dell'Amore that conservationists are able to calculate the
extinction rate of those species by tracking how many of them die out
each year, similar to the technique used to determine a country's
mortality rate. Based on that approach, the study authors determined
that between 100 and 1,000 species were lost per million per year,
primarily due to climate change and habitat destruction resulting from
human causes.
The investigators used a different method to calculate the extinction
rate from before the evolution of the modern human. They reviewed
fossil record data and took note of when species disappeared, then
used statistical modeling to fill in holes in the records, Dell'Amore
said. Those efforts revealed that less than one species out of every
million became extinct annually in the time before modern humans
evolved, she added.
One of the species at risk is the buffy-tufted-ear marmoset, a
creature with thick black fur and a perpetually disgruntled look on
its face, explained Washington Post reporter Terrence McCoy. The
marmoset once resided in the jungles of Brazil, but tremendous
increases in human population led to extensive destruction of its
habitat for agricultural purposes, placing the species in grave
danger.
The study also helped clarify the locations of the most vulnerable
species, as well as where and how people cause changes to the
environment and what role that plays in extinctions, McCoy said. Pimm
and his associates report that many land-based species are distributed
throughout regions smaller than the state of Delaware, and that these
creatures are "geographically concentrated and are disproportionately
likely to be threatened or already extinct."
"Five times, a vast majority of the world's life has been snuffed out
in what have been called mass extinctions, often associated with giant
meteor strikes," Borenstein said. "About 66 million years ago, one
such extinction killed off the dinosaurs and three out of four species
on Earth. Around 252 million years ago, the Great Dying snuffed out
about 90 percent of the world's species."
Fortunately, Pimm and his colleagues said there is still hope, thanks
largely to the use of smartphones and other types of technology that
can help biologists, other scientists and even conservation-minded
citizens locate plant and animal species that are in trouble. Once
they are detected, scientists can attempt to protect habitats and use
techniques such as captive breeding in order to preserve the
threatened plants and animals.
Source: redOrbit Staff & Wire Reports - Your Universe Online
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