Introduction – humans, nature and human nature - Ecological Applications: Toward a Sustainable World - page 2

1.1 Homo
not-so- sapiens ?

Homo sapiens , the name of the most recent in a line of hominids, might well be
considered a misnomer. Just how sapient (wise) has Homo sapiens been? We have
certainly been clever - inventing an amazing array of tools and technologies from
the wheel to the nuclear power station. But how much of the natural world has been
disrupted or destroyed during this technological 'progress'? And is our way of life
actually sustainable? A crunch question is whether your descendants will be able
to enjoy the same opportunities as you. If not, perhaps they will judge their ances-
tors to have been far from wise.
Humans destroy natural ecosystems to make way for urban and industrial devel-
opment and to establish production ecosystems such as forestry and agriculture.
We also exploit the natural world for nonrenewable resources (mining) as well as
renewable ones (fi sheries and forests). Mining destroys habitat directly, and fi shery
techniques such as bottom trawling can physically disrupt habitat. The natural
ecosystems that remain are also affected by human activities. Our harvesting of
species from the wild (whether trees, antelopes or fi sh) has often led to their decline
through overexploitation. Our transport systems allow species from one part of the
world to hitch a ride to another where, as 'invaders', their impacts on native biota
can be profound. And every human activity, including defecation, transport, indus-
try and agriculture, produces 'pollutants' that can adversely affect the biota locally
or globally.
You might imagine there would be consensus about what constitutes reasonable
behavior in our interactions with the natural world. But people take a variety of
standpoints and there are a host of contradictions. Farmers usually consider weeds
that reduce the productivity of their crops to be a very bad thing. But conservation-
ists bemoan the farmers' attack on weeds because these species often help fuel the
activities of butterfl ies and birds. The Nile perch ( Lates nilotica ) was introduced to
Africa's Lake Victoria to provide a fi shery in an economically depressed region, but
it has driven most of the lake's 350 endemic fi sh species towards extinction (Kaufman,
1992). So gains at our dinner tables can equate to a loss of biological diversity.
Then again, our knowledge of plant physiology allows agricultural ecosystems to
be managed intensively for maximum food production. But heavy use of fertilizers
means that excess plant nutrients, particularly nitrate and phosphate, end up in
rivers and lakes. Here ecosystem processes can be severely disrupted, with blooms
of microscopic algae shading out waterweeds and, when the algae die and decom-
pose, reducing oxygen and killing animals. And even in the oceans, large areas
around river mouths can be so badly impacted that fi sheries are lost. The farmers'
gain is the fi shers' loss.
Pesticides, too, are applied to land but fi nd their way to places they were not
intended to be. Some pass up food chains and adversely affect local birds of prey.
Others move via ocean currents and through marine food chains, damaging preda-
tors at the ends of the earth (such as polar bears and the Inuit people of the Arctic).
And hundreds of kilometers downwind of large population centers, acid rain (caused
by emission of oxides of nitrogen and sulfur from power generation) kills trees and
drives lake fi sh to extinction. Ironically, in other parts of the world a new ecology
is imposed in previously fi shless lakes because of the introduction of fi sh favored
by anglers.
So Homo sapiens has a diversity of views and a wide variety of impacts. But are
we really so different from other species?