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The Illinois Nature Preserves Commission, for only the third time in nearly 30 years of existence, has given its approval to the introduction of a new species into one of its preserves. So if Doug Taron can find a few caterpillars, a moth called Papaipema cerina will be released in the Bluff Spring Fen Nature Preserve near Elgin this September.

The commission's approval of this exercise in transanimaling is in some ways a departure from previous policy and in other ways a continuation, or expansion, of older ideas. The issues raised by Papaipema illuminate many of the problems we face in our attempts to retain some vestiges of our native natural landscape in a state where humans are continually reshaping the land.

When the Illinois nature-preserves system was created in 1963, the goal was to discover and preserve the natural gems that remained after a century and a half of wholesale destruction. Scientists scoured the state looking for prairies, wetlands, savannas, forests, and other communities that could reasonably be considered unchanged since settlement began in the early 19th century.

Not surprisingly, these places were all small. Of the 99 preserves created in the first 20 years of the system's existence, only four had more than 1,000 acres and half had fewer than 100. For the most part they were selected because of the presence of "conservative" species of plants, species that would be expected to vanish if their community was hit with a disturbance they weren't accustomed to. Because of their greater mobility, animals, especially vertebrates, are seldom thought of as good indicators of natural quality. So a prairie remnant with a high level of diversity and a good population of white-fringed orchid, or a rich woodland with a population of nodding trillium would be considered for inclusion in the nature-preserve system, while a field of bluegrass and Queen Anne's lace would not, even if that weedy field supported endangered upland sandpipers or Henslow's sparrows.

The Nature Preserves Commission has generally taken a very conservative approach to the management of its lands, and it is easy to see why. Managing tiny parcels of land containing the last remnants of natural Illinois is an awesome responsibility. There is no room for mistakes on a 20-acre prairie. The wrong move could doom the very things you are trying to save.

Dr. Brian Anderson, director of the nature-preserves system, sees avoiding introductions as part of carrying out the goal of preserving presettlement communities. "We don't want species pollution," he told me, "so we don't do species loading."

Behind these phrases is the idea that the plants and animals that should be in a high-quality natural area are already there, and we shouldn't add a species just because it can be found in a similar community elsewhere. Preserves are often thought of as arks, and there is a tendency to want to load them up the way Noah loaded his. However, Noah's ark was designed for 40 days and 40 nights. You couldn't expect all those animals to live there forever.

About 15 years ago, the commission approved the introduction of Franklin's ground squirrels in the Gensberg-Markham Prairie in Markham, but that is the only instance of a species being allowed into a high-quality community thought to be in presettlement condition.

The one other instance of transplantation was at Bluff Spring Fen two years ago when the entire Healy Road Prairie was moved into the preserve. Healy Road was a gravel-hill prairie that was about to be obliterated by its owner. As it happens, a portion of Bluff Spring Fen was a gravel hill whose natural cover had been destroyed, so the move seemed reasonable. Large numbers of free-flying insects, captured in nets, were moved at the same time.

Papaipema cerina is such an obscure little creature that nobody can be sure whether or not it is rare. Entomologists usually catch moths by setting up a black light in the evening. The light lures the moths into a trap whence they can be removed and studied. There is evidence that Papaipema are not attracted to black lights, so population surveys could miss them completely even if they were quite common.

The caterpillars live inside the stems of their host plants, so it is impossible to locate them by sight. To discover a caterpillar you have to look for a host plant that appears to be in a weakened and wilted state. You then carefully cut a slit in the stem and see if the larva is inside.

The caterpillars require at least two different host plants to complete their growth. They begin on Hystrix patula, commonly known as bottlebrush grass, and they continue on Podophyllum peltatum, mayapple. They may also use other plants as hosts, but these two seem to be the essential ones.

Obviously, Papaipema can live only where these two plants occur together. Mayapples are prominent in almost any forest or oak savanna in northern Illinois. They grow in dense clusters that are actually clones. The large number of stems arises from a single interconnected root system. Bottlebrush grass is much less common. It was a major component of oak savanna communities, but there are practically none of those left.

The only known Illinois population of Papaipema--until last year--was at the Nachusa Grasslands, a preserve owned by the Nature Conservancy near Dixon. Ron Panzer of Northeastern Illinois University, the authority on matters lepidopteran in northern Illinois, found it there. Then in 1991 Doug Taron, a volunteer with the conservancy's stewardship network, slit open some feeble-looking mayapples on a remnant savanna in Elgin and found some mysterious caterpillars in the stem. He took them home and successfully reared them to adulthood inside carrots that he sliced open to make room for them. Once he had the adults--about two inches wing tip to wing tip and yellow with brown markings--he was able to identify them.

This year he discovered that the Elgin savanna is about to be developed. When the bulldozers scrape away the mayapples and bottlebrush grass, the moths will go with them. Hence the application to the Nature Preserves Commission for permission to transplant them to the Bluff Spring Fen Nature Preserve, where Taron is costeward.

Steve Packard of the Nature Conservancy praised the Nature Preserves Commission for acting quickly on the request. "They did a difficult thing in approving something that hadn't been studied to death first."

But Anderson says that the approval depended on the fact that the moths will be moved into a community that is in the process of restoration and not into a part of the preserve that contains a pristine presettlement community. "The two food plants occur in a degraded community at Bluff Spring," he says, "so this was consistent with current policy. And we decided it was worth taking a chance, since the alternative was to risk losing half the known population."

Packard is pushing for the creation of "landscape-scale restorations," where reintroductions could be done as a matter of course. "The tiny, gemlike preserves are too small for ecological processes to occur in them. We need to have some preserved land where everything that used to be there--even potentially--has a chance to be part of the mix.

"Conservation biology is a new scientific discipline with a strong element of urgency. It is more important to save than to understand. If we can only save what we understand, we will have impoverished systems. If we can save it, we can study it later."

For Anderson, the buffer zones that are being established around the gems in the nature-preserves system can provide the opportunities for reintroduction. The buffers can be managed with restoration in mind to push them in the direction of the pristine community the buffer zone protects. Meanwhile, they can provide a refuge for rare species without creating species pollution in the pristine communities.

Right now the biggest obstacle in the way of the introduction of Papaipema is the lack of larvae. Doug Taron has been searching, but the drought of the past two months has slowed the growth of everything. So far he has found no bottlebrush grasses or mayapples with the stricken look that indicates the presence of a caterpillar in the stem. If he does find some, and can successfully raise them at home, they will emerge from their cocoons in mid-September. He will release the adults at Bluff Spring Fen, where they will mate. Then the females will locate bottlebrush grass and lay their eggs in leaf litter near the stems.

The eggs will either lie there all winter before hatching in the spring or they will hatch and the tiny caterpillars will spend the winter on the ground. So obscure is the Papaipema that nobody knows for sure which of these things will happen.

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