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February 3, 2011
The Earth is headed towards a mass
extinction not seen since dinosaurs were wiped out 65 million years ago. The
exception will be invasive species like cats and humans. Songbirds might not
make it.
Cat populations are growing across North America and they kill about one billion
birds a year. Cats are responsible for the extinction of 33 bird species
according to biologists. Populations have increased by three times in the last
forty years and there are now 150 million domestic and feral cats roaming the
continent.
We love cats. Kittens are cute and cuddly and kids love to squeeze the stuffing
out of them. But when times get tough, as in the current recession, cats are
just another mouth to feed. That's when they are dropped off at animal shelters
or simply abandoned along the road and left to fend for themselves. Deserted
cats form feral colonies close to food and bird sanctuaries form a convenient
buffet.
It used to be that unwanted kittens would be tied in a gunny-sack and dropped
off a bridge in the cover of dark. Now the trap-neuter-return program is
popular. Wild cats are caught, neutered and returned to feral colonies. The hope
is that they will live out their natural lives and the colonies will eventually
die out; not likely as more cats are abandoned. More often they are sent to cat
shelters like the one in Richmond which is home to 1,000 cats, the largest of
its kind in North America.
Cat lovers have organized to protect them. On such group is called the Alley Cat
Allies. They can be a formidable force as Mayor Mitch Campsall of 100 Mile House
recently found out after he voted in favour of euthanizing the town's feral
cats. He was bombarded by calls and emails from the Alley Cat Allies and the cat
cull was halted.
Cats are just one species that's killing song birds. Rats and the brown-headed
cowbird take their toll. Humans are the greatest danger to birds. Not only are
humans passionate about sustaining bird-killing cats; humans destroy bird
habitants by filling in wetlands, build flight obstacles like high-rises and
wind turbines, and poison the land and air.
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While more than one-half of all of the world's species are doomed,
opportunistic invasive species will thrive. They are weed species that
expropriate local resources and push native species to extinction. Humans
are responsible for carrying invasive species around the globe. For
thousands of years humans have been on the move carrying rats, lice,
disease, microbes, burrs, dogs, pigs, goats, cats, cows, and other forms of
parasitic vermin and domesticated creatures.
We have carried our flea-bitten entourage to places where evolution had not
developed resistance to invaders. Humans themselves were part of the rat
pack that ravaged defenseless native species. When the Dutch sailors landed
on Mauritius, they clubbed and ate vulnerable dodos. The sailors brought
rats and pigs and another primate besides themselves: the opportunistic
Asian monkey who ate almost anything in sight. The monkeys are still a
pestilence on Mauritius; hungry and daring and ready to grab whatever they
can eat, including bird eggs. The dodo hasn't been seen since 1662.
In the oceans, humans are drastically depleting deepwater fish and shellfish
through overharvesting, if not to the point of extinction then at least
enough to cause more cascading consequences. Coral reefs and other
shallow-water ecosystems are devastated, by erosion and chemical runoff from
the land. Our wanton carelessness is leading to mass extinction of many
species.
Remaining species are being corralled into fragmented islands of their
former range where lack of food and genetic diversity will decimate their
numbers further. Canadian policy analyst Thomas F. Homer-Dixon outlines the
effect that humans are having as millions of hectares of croplands are lost
each year including "encroachment by cities, erosion, depletion of
nutrients, acidification, compacting and salinization and waterlogging from
over-irrigation."
While one-half to two-thirds of Earth's species will perish, weed species
will do fine. Sad but true, humans are one of those weed species; just
another invasive species ready to ravage some and cherish others to suit our
own whims. So much for our noble reputation as caretakers of the Earth. The
only good thing that might come of it is the realization of our true place
in nature as weeds.
David Charbonneau is the owner of Trio Technical.
He can be reached at
dcharbonneau13@shaw.ca
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