November 30, 2013 at 6:43 pm #1493MikeKeymaster
Animal Extinction – the greatest threat to mankind
By the end of the century half of all species will be extinct. Does that
By Julia Whitty
Published: 30 April 2007
In the final stages of dehydration the body shrinks, robbing youth from
the young as the skin puckers, eyes recede into orbits, and the tongue
swells and cracks. Brain cells shrivel and muscles seize. The kidneys
shut down. Blood volume drops, triggering hypovolemic shock, with its
attendant respiratory and cardiac failures. These combined assaults
disrupt the chemical and electrical pathways of the body until all
systems cascade toward death.
Such is also the path of a dying species. Beyond a critical point, the
collective body of a unique kind of mammal or bird or amphibian or tree
cannot be salvaged, no matter the first aid rendered. Too few
individuals spread too far apart, or too genetically weakened, are
susceptible to even small natural disasters: a passing thunderstorm; an
unexpected freeze; drought. At fewer than 50 members, populations
experience increasingly random fluctuations until a kind of fatal
arrhythmia takes hold. Eventually, an entire genetic legacy, born in the
beginnings of life on earth, is removed from the future.
Scientists recognise that species continually disappear at a background
extinction rate estimated at about one species per million per year,
with new species replacing the lost in a sustainable fashion. Occasional
mass extinctions convulse this orderly norm, followed by excruciatingly
slow recoveries as new species emerge from the remaining gene-pool,
until the world is once again repopulated by a different catalogue of
flora and fauna.
From what we understand so far, five great extinction events have
reshaped earth in cataclysmic ways in the past 439 million years, each
one wiping out between 50 and 95 per cent of the life of the day,
including the dominant life forms; the most recent event killing off the
non-avian dinosaurs. Speciations followed, but an analysis published in
Nature showed that it takes 10 million years before biological diversity
even begins to approach what existed before a die-off.
Today we’re living through the sixth great extinction, sometimes known
as the Holocene extinction event. We carried its seeds with us 50,000
years ago as we migrated beyond Africa with Stone Age blades, darts, and
harpoons, entering pristine Ice Age ecosystems and changing them forever
by wiping out at least some of the unique megafauna of the times,
including, perhaps, the sabre-toothed cats and woolly mammoths. When the
ice retreated, we terminated the long and biologically rich epoch
sometimes called the Edenic period with assaults from our newest
weapons: hoes, scythes, cattle, goats, and pigs.
But, as harmful as our forebears may have been, nothing compares to
what’s under way today. Throughout the 20th century the causes of
extinction – habitat degradation, overexploitation, agricultural
monocultures, human-borne invasive species, human-induced
climate-change – increased exponentially, until now in the 21st century
the rate is nothing short of explosive. The World Conservation Union’s
Red List – a database measuring the global status of Earth’s 1.5 million
scientifically named species – tells a haunting tale of unchecked,
unaddressed, and accelerating biocide.
When we hear of extinction, most of us think of the plight of the rhino,
tiger, panda or blue whale. But these sad sagas are only small pieces of
the extinction puzzle. The overall numbers are terrifying. Of the 40,168
species that the 10,000 scientists in the World Conservation Union have
assessed, one in four mammals, one in eight birds, one in three
amphibians, one in three conifers and other gymnosperms are at risk of
extinction. The peril faced by other classes of organisms is less
thoroughly analysed, but fully 40 per cent of the examined species of
planet earth are in danger, including perhaps 51 per cent of reptiles,
52 per cent of insects, and 73 per cent of flowering plants.
By the most conservative measure – based on the last century’s recorded
extinctions – the current rate of extinction is 100 times the background
rate. But the eminent Harvard biologist Edward O Wilson, and other
scientists, estimate that the true rate is more like 1,000 to 10,000
times the background rate. The actual annual sum is only an educated
guess, because no scientist believes that the tally of life ends at the
1.5 million species already discovered; estimates range as high as 100
million species on earth, with 10 million as the median guess. Bracketed
between best- and worst-case scenarios, then, somewhere between 2.7 and
270 species are erased from existence every day. Including today.
We now understand that the majority of life on Earth has never been –
and will never be – known to us. In a staggering forecast, Wilson
predicts that our present course will lead to the extinction of half of
all plant and animal species by 2100.
You probably had no idea. Few do. A poll by the American Museum of
Natural History finds that seven in 10 biologists believe that mass
extinction poses a colossal threat to human existence, a more serious
environmental problem than even its contributor, global warming; and
that the dangers of mass extinction are woefully underestimated by
almost everyone outside science. In the 200 years since French
naturalist Georges Cuvier first floated the concept of extinction, after
examining fossil bones and concluding “the existence of a world previous
to ours, destroyed by some sort of catastrophe”, we have only slowly
recognised and attempted to correct our own catastrophic behaviour.
Some nations move more slowly than others. In 1992, an international
summit produced a treaty called the Convention on Biological Diversity
that was subsequently ratified by 190 nations – all except the unlikely
coalition of the United States, Iraq, the Vatican, Somalia, Andorra and
Brunei. The European Union later called on the world to arrest the
decline of species and ecosystems by 2010. Last year, worried
biodiversity experts called for the establishment of a scientific body
akin to the Intergovernmental Panel on Climate Change to provide a
united voice on the extinction crisis and urge governments to action.
Yet, despite these efforts, the Red List, updated every two years,
continues to show metastatic growth. There are a few heartening examples
of so-called Lazarus species lost and then found: the wollemi pine and
the mahogany glider in Australia, the Jerdon’s courser in India, the
takahe in New Zealand, and, maybe, the ivory-billed woodpecker in the
United States. But for virtually all others, the Red List is a dry
country with little hope of rain, as species ratchet down the listings
from secure to vulnerable, to endangered, to critically endangered, to
All these disappearing species are part of a fragile membrane of
organisms wrapped around the Earth so thinly, writes Wilson, that it
“cannot be seen edgewise from a space shuttle, yet so internally complex
that most species composing it remain undiscovered”. We owe everything
to this membrane of life. Literally everything. The air we breathe. The
food we eat. The materials of our homes, clothes, books, computers,
medicines. Goods and services that we can’t even imagine we’ll someday
need will come from species we have yet to identify. The proverbial cure
for cancer. The genetic fountain of youth. Immortality. Mortality. The
living membrane we so recklessly destroy is existence itself.
Biodiversity is defined as the sum of an area’s genes (the building
blocks of inheritance), species (organisms that can interbreed), and
ecosystems (amalgamations of species in their geological and chemical
landscapes). The richer an area’s biodiversity, the tougher its immune
system, since biodiversity includes not only the number of species but
also the number of individuals within that species, and all the inherent
genetic variations – life’s only army against the diseases of oblivion.
Yet it’s a mistake to think that critical genetic pools exist only in
the gaudy show of the coral reefs, or the cacophony of the rainforest.
Although a hallmark of the desert is the sparseness of its garden, the
orderly progression of plants and the understated camouflage of its
animals, this is only an illusion. Turn the desert inside out and upside
down and you’ll discover its true nature. Escaping drought and heat,
life goes underground in a tangled overexuberance of roots and burrows
reminiscent of a rainforest canopy, competing for moisture, not light.
Animal trails criss-cross this subterranean realm in private burrows
engineered, inhabited, stolen, shared and fought over by ants, beetles,
wasps, cicadas, tarantulas, spiders, lizards, snakes, mice, squirrels,
rats, foxes, tortoises, badgers and coyotes.
To survive the heat and drought, desert life pioneers ingenious
solutions. Coyotes dig and maintain wells in arroyos, probing deep for
water. White-winged doves use their bodies as canteens, drinking enough
when the opportunity arises to increase their bodyweight by more than 15
per cent. Black-tailed jack rabbits tolerate internal temperatures of
111F. Western box turtles store water in their oversized bladders and
urinate on themselves to stay cool. Mesquite grows taproots more than
160ft deep in search of moisture.
These life-forms and their life strategies compose what we might think
of as the “body” of the desert, with some species the lungs and others
the liver, the blood, the skin. The trend in scientific investigation in
recent decades has been toward understanding the interconnectedness of
the bodily components, i.e. the effect one species has on the others.
The loss of even one species irrevocably changes the desert (or the
tundra, rainforest, prairie, coastal estuary, coral reef, and so on) as
we know it, just as the loss of each human being changes his or her
Nowhere is this better proven than in a 12-year study conducted in the
Chihuahuan desert by James H Brown and Edward Heske of the University of
New Mexico. When a kangaroo-rat guild composed of three closely related
species was removed, shrublands quickly converted to grasslands, which
supported fewer annual plants, which in turn supported fewer birds. Even
humble players mediate stability. So when you and I hear of this year’s
extinction of the Yangtze river dolphin, and think, “how sad”, we’re not
calculating the deepest cost: that extinctions lead to co-extinctions
because most living things on Earth support a few symbionts, while
keystone species influence and support myriad plants and animals. Army
ants, for example, are known to support 100 known species, from beetles
to birds. A European study finds steep declines in honeybee diversity in
the past 25 years but also significant attendant declines in plants that
depend on bees for pollination – a job estimated to be worth £50bn
worldwide. Meanwhile, beekeepers in 24 American states report that
perhaps 70 per cent of their colonies have recently died off,
threatening £7bn in US agriculture. And bees are only a small part of
the pollinator crisis.
One of the most alarming developments is the rapid decline not just of
species but of higher taxa, such as the class Amphibia, the
300-million-year-old group of frogs, salamanders, newts and toads hardy
enough to have preceded and then outlived most dinosaurs. Biologists
first noticed die-offs two decades ago, and, since then, have watched as
seemingly robust amphibian species vanished in as little as six months.
The causes cover the spectrum of human environmental assaults, including
rising ultraviolet radiation from a thinning ozone layer, increases in
pollutants and pesticides, habitat loss from agriculture and
urbanisation, invasions of exotic species, the wildlife trade, light
pollution, and fungal diseases. Sometimes stressors merge to form an
unwholesome synergy; an African frog brought to the West in the 1950s
for use in human pregnancy tests likely introduced a fungus deadly to
native frogs. Meanwhile, a recent analysis in Nature estimated that, in
the past 20 years, at least 70 species of South American frogs had gone
extinct as a result of climate change.
In a 2004 analysis published in Science, Lian Pin Koh and his colleagues
predict that an initially modest co-extinction rate will climb
alarmingly as host extinctions rise in the near future. Graphed out, the
forecast mirrors the rising curve of an infectious disease, with the
human species acting all the parts: the pathogen, the vector, the
Typhoid Mary who refuses culpability, and, ultimately, one of up to 100
“Rewilding” is bigger, broader, and bolder than humans have thought
before. Many conservation biologists believe it’s our best hope for
arresting the sixth great extinction. Wilson calls it “mainstream
conservation writ large for future generations”. This is because more of
what we’ve done until now – protecting pretty landscapes, attempts at
sustainable development, community-based conservation and ecosystem
management – will not preserve biodiversity through the critical next
century. By then, half of all species will be lost, by Wilson’s
To save Earth’s living membrane, we must put its shattered pieces back
together. Only “megapreserves” modelled on a deep scientific
understanding of continent-wide ecosystem needs hold that promise. “What
I have been preparing to say is this,” wrote Thoreau more than 150 years
ago. “In wildness is the preservation of the world.” This, science
The Wildlands Project, the conservation group spearheading the drive to
rewild North America – by reconnecting remaining wildernesses (parks,
refuges, national forests, and local land trust holdings) through
corridors – calls for reconnecting wild North America in four broad
“megalinkages”: along the Rocky Mountain spine of the continent from
Alaska to Mexico; across the arctic/boreal from Alaska to Labrador;
along the Atlantic via the Appalachians; and along the Pacific via the
Sierra Nevada into the Baja peninsula. Within each megalinkage, core
protected areas would be connected by mosaics of public and private
lands providing safe passage for wildlife to travel freely. Broad,
vegetated overpasses would link wilderness areas split by roads. Private
landowners would be enticed to either donate land or adopt policies of
good stewardship along critical pathways.
It’s a radical vision, one the Wildlands Project expects will take 100
years or more to complete, and one that has won the project a special
enmity from those who view environmentalists with suspicion. Yet the
core brainchild of the Wildlands Project – that true conservation must
happen on an ecosystem-wide scale – is now widely accepted. Many
conservation organisations are already collaborating on the project,
including international players such as Naturalia in Mexico, US national
heavyweights like Defenders of Wildlife, and regional experts from the
Southern Rockies Ecosystem Project to the Grand Canyon Wildlands
Council. Kim Vacariu, the South-west director of the US’s Wildlands
Project, reports that ranchers are coming round, one town meeting at a
time, and that there is interest, if not yet support, from the insurance
industry and others who “face the reality of car-wildlife collisions
At its heart, rewilding is based on living with the monster under the
bed, since the big, scary animals that frightened us in childhood, and
still do, are the fierce guardians of biodiversity. Without wolves,
wolverines, grizzlies, black bears, mountain lions and jaguars, wild
populations shift toward the herbivores, who proceed to eat plants into
extinction, taking birds, bees, reptiles, amphibians and rodents with
them. A tenet of ecology states that the world is green because
carnivores eat herbivores. Yet the big carnivores continue to die out
because we fear and hunt them and because they need more room than we
preserve and connect. Male wolverines, for instance, can possess home
ranges of 600 sq m. Translated, Greater London would have room for only
The first campaign out of the Wildlands Project’s starting gate is the
“spine of the continent”, along the mountains from Alaska to Mexico,
today fractured by roads, logging, oil and gas development, grazing, ski
resorts, motorised back-country recreation and sprawl.
The spine already contains dozens of core wildlands, including
wilderness areas, national parks, national monuments, wildlife refuges,
and private holdings. On the map, these scattered fragments look like
debris falls from meteorite strikes. Some are already partially buffered
by surrounding protected areas such as national forests. But all need
interconnecting linkages across public and private lands – farms,
ranches, suburbia – to facilitate the travels of big carnivores and the
net of biodiversity that they tow behind them.
The Wildlands Project has also identified the five most critically
endangered wildlife linkages along the spine, each associated with a
keystone species. Grizzlies already pinched at Crowsnest Pass on Highway
Three, between Alberta and British Columbia, will be entirely cut off
from the bigger gene pool to the north if a larger road is built.
Greater sage grouse, Canada lynx, black bears and jaguars face their own
lethal obstacles further south.
But by far the most endangered wildlife-linkage is the borderland
between the US and Mexico. The Sky Islands straddle this boundary, and
some of North America’s most threatened wildlife – jaguars, bison,
Sonoran pronghorn, Mexican wolves – cross, or need to cross, here in the
course of their life’s travels. Unfortunately for wildlife, Mexican
workers cross here too. Men, women, and children, running at night,
one-gallon water jugs in hand.
The problem for wildlife is not so much the intrusions of illegal
Mexican workers but the 700-mile border fence proposed to keep them out.
From an ecological perspective, it will sever the spine at the lumbar,
paralysing the lower continent.
Here, in a nutshell, is all that’s wrong with our treatment of nature.
Amid all the moral, practical, and legal issues with the border fence,
the biological catastrophe has barely been noted. It’s as if extinction
is not contagious and we won’t catch it.
If, as some indigenous people believe, the jaguar was sent to the world
to test the will and integrity of human beings, then surely we need to
reassess. Border fences have terrible consequences. One between India
and Pakistan forces starving bears and leopards, which can no longer
traverse their feeding territories, to attack villagers.
The truth is that wilderness is more dangerous to us caged than free –
and has far more value to us wild than consumed. Wilson suggests the
time has come to rename the “environmentalist view” the “real-world
view”, and to replace the gross national product with the more
comprehensive “genuine progress indicator”, which estimates the true
environmental costs of farming, fishing, grazing, mining, smelting,
driving, flying, building, paving, computing, medicating and so on.
Until then, it’s like keeping a ledger recording income but not
expenses. Like us, the Earth has a finite budget.
Reprinted with permission from Mother Jones magazine. © 2007, Foundation
for National Progress. The Fragile Edge: Diving and Other Adventures in
the South Pacific by Julia Whitty is published by Houghton Mifflin on 7
More than 16,000 species of the world’s mammals, birds, plants and other
organisms are at present officially regarded as threatened with
extinction to one degree or another, according to the Red List.
Maintained by the Swiss-based World Conservation Union (usually known by
the initials IUCN), the Red List is one of the gloomiest books in the
world, and is set to get even gloomier.
Since 1963 it has attempted to set out the conservation status of the
planet’s wildlife, in a series of categories which now range from
Extinct (naturally), through Critically Endangered, Endangered,
Vulnerable and Near-Threatened, and finishing with Least Concern. The
numbers in the “threatened” categories are steadily rising.
Taxonomists at the IUCN regularly attempt to update the list, but that
is a massive job to undertake – there are about 5,000 mammal species in
the world and about 10,000 birds, but more than 300,000 types of plant,
and undoubtedly well over a million insect species, and perhaps many
more. Some species, such as beetles living in the rainforest canopy,
could become extinct before they are even known to science.
The last Red List update, released in May last year, looked at 40,168
species and considered 16,118 to be threatened – including 7,725 animals
of all types (mammals, birds, reptiles, fish, insects etc) and 8,390
What has happened to the bees? What will be the consequences?
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