Busse Woods was among the first natural areas to be set aside as an Illinois nature preserve. The 440-acre hardwood forest, which is part of the Ned Brown Forest Preserve in Elk Grove Village, was also cited in the early 60s by the federal government as a uniquely diverse remnant of the native landscape. Only one other place in Illinois–Volo Bog–has received such recognition.
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A survey of the plants of Busse Woods conducted in 1983 revealed that 26 species that had grown there in the early 60s had disappeared. The famous spring wildflower display was almost completely gone. But now, after eight years of deer population control, there are some encouraging signs of regeneration. Dutchman’s-breeches were rediscovered last year, and large-flowered trillium–which had hung on here and there in the shelter of downed logs–is appearing again out in the open.
But according to Chris Anchor, a wildlife biologist with the Cook County Forest Preserve District, “regeneration has been painfully slow. The deer abundance continued for so many years that many plants were extirpated.” The wildflowers of a woodland spring are perennials. Each year a bulb or other underground structure sends up new green shoots and new flowers. The bulbs live for many years, and they can survive a few years of having their leaves clipped by browsing deer. But if the clipping continues for six or eight years, the bulbs die.
A fundamental question for all those involved in controlling the deer herd is how many deer are enough? The answer needs to be tailored to the individual site. A good healthy woodland can support about 18 deer per square mile. In the Des Plaines River valley, where years of heavy deer browsing have seriously degraded the woods, five to seven animals per square mile would be an appropriate density. The preserves around Crabtree Nature Center near Barrington could sustain as many as 25 to 30 animals per square mile because there are still cornfields in the area to supply food.
Among the rarities sheltered at Somme were two milkweeds. One of these has disappeared completely; the other, which is not known to grow anywhere else in the state, is dwindling. An annual called maple-leaved goosefoot that grew under the oaks of the savanna has vanished completely. There may still be seeds in the ground that will sprout next year, but we don’t know if this one will come back. Of course if it does grow next year, the deer will probably eat it all again.
Busse Woods is also showing us that controlling deer numbers can work. In addition to the return of some of the woodland plants, reduced numbers are producing larger, healthier deer. The whole ecosystem is benefiting from the control of the white-tails.
