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 young caterpillars.

	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 water flows.

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 his efforts.