Graphic: Extinction crisis puts 1 million species on the brink

The Brink's

23/12/2022 18:44

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              Graphic on "Extinction"
      
    

  
    By Katy Daigle and Julia Janicki
       Dec 23 (Reuters) - Nature is in crisis, and it's only
getting worse. As species vanish at a rate not seen in 10
million years, more than 1 million species are currently on the
brink. 
    Humans are driving this extinction crisis through activities
that take over animal habitats, pollute nature and fuel global
warming, scientists say. A new global deal to protect nature
agreed on Dec. 19 has the potential to help, and scientists are
urging the world’s nations to ensure the deal is a success. 
    When an animal species is lost, a whole set of
characteristics disappears along with it - genes, behaviors,
activities and interactions with other plants and animals that
may have taken thousands or millions - even billions - of years
to evolve. 
    For related graphic, please click here.  
    Whatever role that species played within an ecosystem is
lost too, whether that's pollinating certain plants, churning
nutrients in soil, fertilizing forests or keeping other animal
populations in check, among other things. If that function was
crucial to the health of an ecosystem, the animals'
disappearance can cause a landscape to transform. 
    Lose too many species and the results could be catastrophic,
leading an entire system to collapse.
    GONE FOREVER
    In the last five centuries, hundreds of unique animals have
vanished across the world, such as the flightless Dodo bird
killed off from the island of Mauritius in the late 1600s. 
    In many cases, humans were to blame - first by fishing or
hunting, as was the case with South Africa's zebra subspecies
Quagga hunted to its end in the late 19th century - and more
recently through activities that pollute, disrupt or take over
wild habitats. 
    Before a species goes extinct, it may already be considered
"functionally extinct" – with not enough individuals left to
ensure the species survives. More recent extinctions have
allowed humans to interact with some species' last known
individuals, known as "endlings". When they go, that's the end
of those evolutionary lines – as occurred in these iconic cases:
    * "Toughie" was the last known individual of the Rabb's
Fringe-Limbed tree frog. All but a few dozen of his species had
been wiped out by chytrid fungus in the wild in Panama. In his
enclosure at the Atlanta Botanical Garden, he was calling out in
vain for a mate that didn’t exist. He died in 2016.
    * The story of passenger pigeon "Martha" is a cautionary
tale for
conservation: in the 1850s there were still millions of
passenger pigeons, but they were eventually hunted to extinction
as conservation measures were taken only after the species was
past the point of no return. Martha, the last, died in 1914 at
the Cincinnati Zoo.
    * "Lonesome George", found in 1971, was Ecuador's last
​​Pinta
Island tortoise. From the 17th century, some 200,000 individuals
were hunted for their meat. Later, they struggled to compete for
food after goats were brought to the island in the 1950s.
Scientists tried to save the species through captive breeding
before George died in 2012.
    * "Ben" or "Benjamin" was the world's last known thylacine,
a
marsupial carnivore also known as the Tasmanian tiger. The
animal was given protective status only two months before
Benjamin died in 1936 in the Beaumaris Zoo in Tasmania.

    ON THE BRINK
    There are some species that could soon be reduced to their
own endlings. The world's smallest porpoise - Mexico's
critically endangered vaquita - is down to just 18 individuals
in the wild, as populations have been ravaged by fishing nets. 
    The Northern white rhino subspecies, the second-largest land
mammal after elephants, has no hope of recovery after the last
male died in 2018. Only a female and her daughter are left. 
    These stories of endlings matter, scientists say, precisely
because so many extinctions happen out of sight. 
    "Somewhere in the core of our humanity, we recognize these
creatures, we're touched by their story, and we feel compassion
- and maybe also a moral compulsion - to help," said Paula
Ehrlich, president and CEO of the E.O. Wilson Biodiversity
Foundation. 
    The Northern white rhino isn't just a part of the world, she
said. It's a world unto itself - its own ecosystem - mowing
fields through grazing, fertilizing lands where it walks, having
insects land on its skin, and then with birds feeding off those
insects. 
    "Understanding everything that an animal is and does for the
world helps us understand that we, too, are a part of nature -
and we need nature to survive," Ehrlich said. 
    EXTINCTION OVER TIME
    Unlike with the endlings, most species simply fade away in
the wild without people noticing.
    Scientists count 881 animal species as having gone extinct
since around 1500, dating to the first records held by the
International Union for Conservation of Nature (IUCN) – the
global scientific authority on the status of nature and
wildlife. That's an extremely conservative estimate for species
extinction over the last five centuries, though, as it
represents only the cases resolved with a high degree of
certainty. 
    If we include animal species that scientists suspect might
be extinct, that number shoots up to 1,473. The bar is high for
declaring a species extinct – a sobering task that scientists
are already reluctant to do. 
    "It's hard to prove the negative, to prove you can't find
it," said Sean O'Brien, an ecologist who heads the NatureServe
nonprofit working to establish definitive data on North American
species. "And it's emotional. A botanist doesn't want to declare
it extinct because it feels like a failure." 
    Among terrestrial vertebrates, or land animals with a
backbone, 322 species have been declared extinct since 1500. Add
in the number of possibly extinct species and the tally comes to
573.
    For moisture-loving amphibians, vulnerable to both pollution
and drought, things are looking particularly bleak with the
extinction rate escalating over the last few decades. Only 37
species have been declared extinct with a high degree of
certainty since 1500. But scientists suspect more than 100
others have disappeared over the last 30-40 years, according to
a 2015 study in the journal Science Advances.
    Last recorded sightings increase over time, especially from
the mid-19th century start of the Industrial Revolution. That
shows animals have been at increasing peril, but also that our
knowledge of nature has improved as we study and survey more
species. 
    There are many notable species among those that have
vanished since 1500. The dodo was last seen in 1662, within 65
years of it first being recorded. The Pinta Island tortoise was
last seen in the wild in 1972. 
    Some vanishings have inspired public outcry, such as the
2016 extinction declaration for the tiny Christmas Island
pipistrelle bat species, last seen in 2009. It was Australia's
first recorded mammal extinction in 50 years. 
    Losing hundreds of species over 500 or so years may not seem
significant when there are millions more still living on the
planet. But the speed at which species are now vanishing is
unprecedented in the last 10 million years. 
    "We are losing species now faster than they can evolve,"
O'Brien said. 
    MASS EXTINCTIONS
    Plenty of animals have gone extinct naturally or due to
causes unrelated to human activity. In a healthy environment, as
species die off naturally, new species evolve – and an
evolutionary balance is maintained. 
    This turnover relies on what scientists consider a normal or
background extinction rate. 
    But when the extinction rate jumps so high that more than
75% of the world's species go extinct within the relatively
short time frame of less than 2 million years, this is
considered a mass extinction event. 
    That's happened five times over the last half-billion years,
which we know through studying Earth's fossil record - with
layers upon layers of sediment having buried the remains of
animals over time. When a layer with a large and diverse number
of animals is found, scientists can see that a mass die-off
occurred. 
    Scientists warn we have entered a sixth mass extinction.
    Under a normal extinction rate scenario, it would have taken
at least 800 years and up to 10,000 years for the high number of
vertebrate extinctions that we've seen in the last century,
according to the 2015 paper in Science Advances. 
    "Despite our best efforts, the extinction rate is still
estimated to be 1,000 times higher than before humans entered
the stage," Ehrlich said. "At this rate, half will be gone by
the end of the century."
UNKNOWN AND STILL UNDER THREAT
    As bad as it seems, scientists say the reality is likely
even worse. Looking only at species extinctions doesn't give the
full picture, partly because scientists are so conservative in
saying a species is gone. For example, even though Toughie was
the last known individual of his kind, the IUCN lists his
species still as "critically endangered, possibly extinct."
    More importantly, there is a vast reservoir of species that
we have yet to discover. Scientists have identified some 1.2
million species in the world, but estimate there are about 8.7
million. That leaves roughly 7.5 million species that we think
are out there but know nothing about – including whether or not
they're in trouble. 
    "Knowing what we do about the impact of climate change and
habitat loss, it's hard to imagine that thousands if not
millions of species are not in the process of going extinct
right now," O'Brien said. 
    CONSERVATION GIVES HOPE AS POPULATIONS DECLINE
    The IUCN uses a range of categories to describe the state of
a species, as a way of identifying which are in trouble and when
to help. But a species being listed as "least concern" or "near
threatened" doesn't mean its populations are stable. 
    African lions, for example, have been listed for decades as
"vulnerable," but their numbers dropped 43% in 1993-2014, when
the last population data was available. Dugongs, the chubby
marine mammals also known as a sea cows, are listed globally as
"vulnerable" even as their plummeting populations in East Africa
and New Caledonia were updated to "endangered" in December. 
    The decline of one or more populations of a species can mark
the start of a trend toward extinction. 
    As sobering as the situation may seem at a global scale,
there are reasons for hope. The newly adopted Kunming-Montreal
Global Biodiversity Framework in December will guide global
conservation efforts through the decade to 2030. Among other
things, the deal envisions putting 30% of the planet’s land and
sea areas under protection by decade’s end. 
    "It's so overwhelming to think there are these species right
on the edge," O'Brien said. "But then the conservationists I
work with remind me of how much people care." 
    Between 1993 and 2020, conservation measures such as habitat
restoration or captive breeding helped to prevent the extinction
of up to 32 bird species and as many as 16 mammals worldwide,
according to conservative estimates in a 2020 study published in
the journal Conservation Letters. 
    "Science is democratizing the information for every country
to know what it needs to do where," said Ehrlich of the Wilson
Foundation, which works to identify the best places in the world
for protecting biodiversity and prioritizing nature. Before he
died last year, Edward O. Wilson advocated putting half the
planet under conservation and estimated that would save 85% of
the world's species. 
    "We humbly need to do the best that we can to protect them
now," Ehrlich said. "We understand more about the intricate web
of life that sustains nature – and us, as a part of nature." 
    <^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
On The Brink    https://www.reuters.com/graphics/GLOBAL-ENVIRONMENT/EXTINCT/lbvgggdgevq/
Key takeaways from the COP15 biodiversity summit     urn:newsml:reuters.com:*:nL8N33903A
ANALYSIS-U.N. nature deal can help wildlife as long as countries
deliver     urn:newsml:reuters.com:*:nL1N33A21M
Nearly 10% of marine life threatened with extinction -Red List  
  urn:newsml:reuters.com:*:nL8N32Y4KC
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 (Reporting by Katy Daigle in Washington D.C. and Julia Janicki
in Paris; Editing by Diane Craft)
 ((Katy.Daigle@thomsonreuters.com;))