A pair of "green thumb" projects near Chicago bear lessons for restoring the environment.
One effort, by the Nature Conservancy, seeks to rebuild the savannah ecology that existed on a 90-acre tract before settlement destroyed it. Savannahs -- grassy vistas broken by scattered oaks -- differ from forests in their smaller number of trees. They differ from the prairies usually associated with the Great Plains by their distinctive plant and animal species. The conservancy group first tried to resurrect a prairie on the land after burning off non-native vegetation. This fizzled, but new neighbors moved in: thistles, cream gentians and yellow pimpernels, thriving in the partial shade of the oaks that had made it so hard for prairie plants.
The Nature Conservancy searched old records to learn what plants lived on the Illinois savannah before civilization arrived. Identifying 100 "associated" species, the group harvested seeds from surviving members in odd places such as railroad rights-of-way and old cemeteries. After replanting, the naturalists were pleased and surprised to find uncommon species of butterflies and birds, including a pair of Eastern bluebirds, moving in.