Feature Article February 5, 2003
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Creeping
Impactsby
Gray MerriamTalk
of our impacts on the environment often seems to suggest that the only
important impacts are big, severe and obvious. Don't believe it.
Environmental impact statements sometimes have trouble dealing with
them, but many of our impacts these days creep up on things rather
than blasting them out of their habitats.
The contamination of well water in Sydenham was not sudden. It was
slow, and crept up on people over along time. But there is no question
that it eventually became an important impact on their environment
(and wallets).
What has been the creeping effect of our introduction of snowmobiles
and ATV's into previously quiet stretches of bush? Push it up one
step. What have highways done over time to the environments along
them? Not only do they turn wildlife into roadkill, but the effects of
highways and motorized trails extend well beyond a narrow traveled
line. Vegetation, with or without leaves, does not stop much noise. It
takes solid, flat things like the noise barriers along superhighways.
A multi-year study in the Netherlands showed that highway noise
reduced the successful nesting of several bird species for up to 200
metres on each side of the road. The Dutch government has now dug some
of their new roads down into giant trenches so that the side walls
catch some of the noise and better protect the environment beyond.
We create many creeping impacts that are hard to notice. I live on a
small peninsula that is hard to get to for many kinds of wildlife. We
have built our houses along both edges of the peninsula and our road
down the middle. Foxes that used to have pups here only visit
occasionally now. Without considering how activities around homes
restrict the movement of some species, our impacts crept through most
of the habitat. Some wildlife can no longer live with us. Dogs, cats,
humans, smoke, noise, and light, can all do it, depending on the
sensitivity of the wildlife.
If
we plan a housing development, how many dogs does that mean? How much
noise? How much excess light going into the night forest? Dogs from
homes built near the woods can put an end to nearby deeryards. But
cats, both yours and the ones dropped off along the road, can be an
even greater impact creeping out from our houses into the surrounding
habitats. Good, multiyear studies have shown that not only do cats
reduce the numbers of many kinds of wildlife but they also can
completely exterminate some species locally. It may be cruel but
fortunate that coyotes like cats.
Some species are more sensitive than others to our creeping impacts.
Other species have learned to live with humans and even to use
resources that we supply, like our garbage. As our impacts creep up on
them, we chase away sensitive species and soon the only species that
we can see and experience close to home are tolerant ones like
raccoons, gray squirrels, crows and, eventually, in cities, just
Norway rats, starlings and pigeons.
