Extinctions

Threaten Us All

Science Matters

Dr. David Suzuki

TL. World Conservation Union
recently released its annual Red List of
endangered species. For 2007, another
200 species were added to the existing
list of over 16,000.

But what many people often don’t
realize is that the decline of these
species isn’t just a sad story that’s
happening “out there” in nature; it’s
really a story that’s happening to us, one
that we’re doing to ourselves. And it’s
making all of the ecosystems that we
ultimately depend on biologically poorer
and more vulnerable.

Living in cities, it’s easy to forget
how much we depend on the services
provided by healthy natural ecosystems
- things like cleansing water, filtering
air and storing carbon to reduce global
warming. Our health and well-being
depend on these services, which have
also been conservatively estimated at
being worth trillions of dollars to the
global economy.

However, reading stories about how
species are being pushed to the brink of
extinction doesn’t necessarily trigger
alarm bells about our own future. Many
of the animals in these types of stories
have exotic names from far-away places,
like the Yangtze River dolphin and the
western lowland gorilla, so it’s easy to
gloss over it as someone else’s problem.
But the reality is, in an interconnected
world their problem is our problem.

As hard as it may be for some people
to believe, the other species of the
world don’t exist just to look pretty and
give tourists something to photograph.
They actually fulfill ecological niches.
Their mere existence is often vital to
the overall health of the ecosystem.

 

 

Losing a species or having one pushed
to the brink of extinction can have what
biologists call “cascading” effects on
the entire region.

Consider the role of large primates
in tropical forests. In these forests, large
primates play several important roles,
one of which is in seed dispersal. Many
tropical primates are frugivores, that
is, their diet consists largely of fruit.
While small-seeded fruit trees may have
a large number of species, including
mammals, reptiles and birds, to help
them spread their seeds, large-seeded

tropical fruit trees rely largely on bigger
mammals - especially primates.

When primates, like monkeys, apes
and chimps eat fruit, they physically
spread the seeds over a wide area of
forest floor. So the animals receive
sustenance from the fruit, while the
trees get their seeds spread across a
large area, allowing them to grow
elsewhere, which
then provides

its large primates. The other section was
protected from hunting. The researchers
found that there were 55 per cent fewer
species of large-seeded fruit trees in the
unprotected forest and 60 per cent less
of the fruit trees themselves. In other
words, once the large primates were
gone, the trees that depended on them
started to disappear too.
Of course, as the
researchers point out,

more food for the 66 this has a number
primates. It’s a t h € Oo t h er of unfortunate
mutually beneficial : consequences. It
relationship. S Pp ecles of t he makes the forest less
But when ’ ‘ hospitable to large
large primates are wor ld do n t EX1S t primates, so they are
hunted to greatly less likely to be able

reduced numbers,

as they increasingly
are, it can have a
profound impact on
the ecosystem. For
example, a recent
special edition of the
journal Biotropica
focused on the
impact of what’s
called the “bushmeat” trade - local
hunting that often includes primates.

In one study, researchers from the
University of Illinois looked at two
sections of Peruvian forest. One section
had been heavily hunted by local people
using modern weapons, like shotguns,
and had lost more than 80 per cent of

Just to look pretty
and give tourists
something to
photograph”

to ever come back.
Having less fruit
tree diversity makes
remaining primates
more vulnerable in
times of scarcity. And
the trees themselves,
which often have
economic value to
humans for timber,
fruit or other uses, start to disappear.

Humans depend on the services
provided by healthy ecosystems, so
it’s in our best interests to conserve the
creatures that live in them. Losing one
species or having 200 more hunted off
to the brink of extinction isn’t just sad
news for us - it’s dangerous.

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