First, Do No Harm
You will read in this issue about
a new scourge being visited upon thousands of acres of
Chicago Wilderness this season. I write not of the gypsy
moths, but of the massive aerial spraying of Btk to attempt
to slow (not stop) the spread of gypsy moths in this region.
Arthur Pearson ably describes the advent of the moths
and what we know about their habits in
his article. Btk, he points out, is a natural substance,
harmful only to caterpillars alive in the woods during
a brief three-to-four week period from mid-May to June.
Make no mistake. Spraying Btk will
kill all the young caterpillars that are out in the woods
at that time, not just gypsy moth caterpillars, all the
Are our woods as rich without their butterflies?
Photo by Stephen Packard.
Many butterfly species are common
and widespread and will flit right back from somewhere
unsprayed nearby. But the glory of Chicago Wilderness
is that we have a great many species that are not common.
We live in a region of wild remnants, fragments of once
vast ecosystems that exist now only as islands surrounded
by human development. Most of the rare species of flowers
and butterflies that continue to survive in this region
are remnant-dependent. The Karner blue butterfly can only
live in an area where its primary food, the wild lupine,
grows in great numbers, and there are only a few such
areas known to this region.
Similarly, the pipevine swallowtail
(thriving in only one forest), the Aphrodite fritillary
(prairie-dependent) and other butterfly species that depend
upon high-quality habitat for their survival are hanging
on in this region because we have preserved this habitat
and are managing it for the benefit of biological diversity.
And these rare species will very likely not come back
if their little caterpillars are sprayed with Btk. Their
populations may be too small and too widely scattered
to repopulate an area.
The first question all of us must
ask as we witness the spread of gypsy moths is this: is
it wise to wipe out many populations of rare butterfly
species when the pest we are targeting will survive and
spread anyway? Secondly, what will happen to the birds
that depend on the caterpillars for their sustenance?
If the butterflies go, will the birds go too?
The precautionary principle, which
first gained international prominence in an ocean treaty
(regarding dumping of hazardous wastes), is gaining momentum
internationally as a principle to guide decisionmaking
in the absence of certainty regarding the consequences
of potentially harmful activities. In essence, this principle
states that intrusions into nature can no longer be treated
as an afterthought, and caution can no longer be delayed
on the basis that harm has not been conclusively "proven"
in every detail.
What shall we do about gypsy moths?
It's simple. Learn to live with them. They are here. We
cannot remove them from the landscape. (We can protect
individual trees on our own properties, and we can protect
certain heritage trees on our public lands. We can also
test and try alternative treatments that target gypsy
moths and not all caterpillars.)
We cannot stop the gypsy moths. Some
of our woods will be defoliated by their chomping for
a while, it is true. But the moths will move on and most
of the trees will leaf out again. A few trees will die.
Our time and money are much more wisely spent, however,
restoring health to whole natural communities, enabling
them to better withstand the irruption of pest species
like gypsy moths. Our challenge is to restore natural
disturbance processes on which most of this region's wilderness
depends. This means the careful use of prescribed fires,
thoughtful removal of invasive species, a return to historic
No one welcomes the gypsy moth. Our
woods will be less conventionally pretty during their
occasional outbreaks. But they are here. We cannot stop
them. So for goodness sake let us at least be wise
and responsible and save our best nature reserves
from the scourge of spraying. Let us keep focus on the
first principle of intelligent tinkering to save
all the parts.
Close readers of our masthead
will note a new name appearing there. We welcome Don Parker,
associate editor. This magazine is already better from