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Roadkill points to too many of us |
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Written by SUSAN TWEIT, Writers on the Range
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Wednesday, 01 October 2008 |
I'm a student of roadkill. I keep an informal tally of the carcasses I spot on
the roadside – what kind, how many and where -- and I note the splatters that
accumulate on our car windshield. They're an indication of the diversity and
abundance of animal and insect lives along the unnatural transects we call
highways.
I know when spring has arrived in my southern Colorado valley as much by the
increase in mangled mule deer on the roadside as by the pale green tint that
washes this high-desert landscape. The up-tick in deer kill comes when these
grazers home in on the smooth brome grass planted on the road margins by the
highway department; the brome greens up before the native grasses, providing
early and nutritious -- if risky -- grazing.
Similarly, the progress of
the Arkansas River caddisfly "hatch" is just as easily read in the numbers of
winged adult caddisflies smeared on vehicle windshields, and the quarts of wiper
fluid used to remove them, as it is by the number of anglers in the
river.
Roadkill may seem like a macabre measure of biological diversity,
but it provides interesting, if wrenching, information. It wasn't until I read a
recently published study, however, that I realized roadkill also tells us
something about the species doing the tallying – and the killing.
In 17
months of roadkill census, researchers at Purdue University found 10,500
carcasses representing more than 65 species of wildlife, most of those from a
one-mile stretch of highway traversing a bog. I was so shocked by those numbers
that I had to read them twice: 10,500 animals killed on the road in less than
two years. And the total carnage may actually have been five times higher. There
wasn't enough left of many of the carcasses to count, and larger animals often
manage to make it off the road before they die and are therefore not
discovered.
Perhaps the mortality is less shocking when you learn it was
mostly frogs: bullfrogs, leopard frogs, and other frog species. The other dead
included deer, opossums, raccoons, chimney swifts, garter snakes and
salamanders.
Thousands of dead frogs may not seem like much of a concern.
But frogs are one of the threads that weave the webs of relationships we call
ecosystems, the natural "technology" that keeps our planet green and
habitable.
Frog tadpoles chow down on mosquito larvae by the mouthful,
keeping populations of the blood-sucking and disease-carrying insects in check
without deadly insecticides. Frogs are also a major food source for larger
species, from trout and river otters to bald eagles. Massive frog roadkill thus
deprives other wildlife of food. Worse still, it attracts other creatures to the
road to feed on the dead.
The study's authors suggest that roadkill may
be an as-yet-unexamined factor in the worldwide crash of amphibian populations,
including the frogs and toads once captured by the jar-full by children
throughout North America.
The researchers propose some solutions: Don't
route roads through wetlands, provide wildlife with routes over roads or through
underpasses, and fence highways to keep wildlife away from the killing
zone.
Those are all very nice, but it seems to me that they fail to
tackle the underlying problem. And that problem is, of course, overpopulation --
not on the part of the wildlife, but on the part of the species doing the
road-killing and the tallying -- Homo sapiens. Us.
There are too many of
us. The world's human population has reached nearly 6.7 billion, twice as many
people as there were 50 years ago; we're adding another million humans about
every four days.
We're the ones building the roads. We're the ones
driving the cars. And no, the rise in the price of gas isn't expected to curtail
driving enough to really benefit wildlife; it's just likely to push drivers into
smaller vehicles. With so many of us, there is simply less room, less food, less
habitat, less chance of "them" surviving -- the other 1.8 million known species
with whom we share this planet.
Hence the 10,000-plus frogs killed on a
one-mile stretch of road. And the wars, the shortages of food, water and fuel,
and global climate change. We're the source of the problem. And we're ignoring
it. What if we acknowledged that our overpopulation is a serious issue? What if
we said it out loud: There are too many of us.
There. The sky did not
fall, the world did not end. Let's acknowledge our overpopulation, and do
something about it, before it gets worse. The frogs and caddisflies and deer and
the ecosystems they participate in will thank us.
Susan Tweit is a
contributor to Writers on the Range, a service of High Country News (hcn.org).
She is a writer and naturalist in Salida, Colorado.
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Last Updated ( Wednesday, 01 October 2008 )
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