CHAMPAIGN, Ill. -- Intentional burning in oak savannas is helping many bird populations, such as the red-headed woodpecker, based on preliminary findings of a three-year study in Illinois.
"In the Midwest, the conservation status of birds associated with savannas and open woodlands has not been promising," said Jeffrey D. Brawn, a scientist with the Illinois Natural History Survey and a professor of ecology, ethology and evolution at the University of Illinois.
In a report Aug. 12 at the annual meeting of the Ecological Society of America in Albuquerque, N.M., Brawn described his work in the Peoria Wilds, a series of conservation areas along the Illinois River, and in the Sand Prairie Scrub Oak State Natural Area to the south in Mason County.
"When you burn, some bird species go down in abundance," he said. "Fire selects against those species, but it enhances some other species." Among the species benefiting in Illinois is thered-headed woodpecker -- whose presence in the Midwest has declined almost 2 percent a year since 1966 -- as well as northern orioles, summer tanagers, rose-breasted grosbeaks and great crested flycatchers.
The findings may be welcome news for conservationists wanting to restore oak savannas forests with open canopies that allow light to shine through easily. Years of fire suppression have eliminated natural disturbances such as wildfires. As a result, forest canopies have closed, altering the flow of light to the ground and bringing about ecological changes: Shade-tolerant maple trees have replaced oaks; ground cover has become fragmented; and bird and animal populations have changed.
Oak savannas flourished in Illinois for at least 8,000 years before modern agriculture and development began encroaching. Landscape-management issues have become hot topics in the Midwest and in the West. Prescribed burning, Brawn said, will result in major changes within 10 years. "We have to develop an understanding of what happens to all of the populations of plants and animals."
Brawn's research -- funded by the Illinois Department of Natural Resources and the Nature Conservancy -- has been aimed at getting a snapshot of bird communities in closed- and open-canopy forests, and of the impact of fires on the bird populations. Daily survival rate of nests in burned areas for rose-breasted grosbeaks, for example, was 96 percent. The rates in unburned areas was 92 percent. Even such a small difference, Brawn said, can mean a big difference in productivity and nesting success.
"We haven't been able to find a lot of ways to increase the reproductive success of birds living on the state's fragmented landscape," he said. "It's been a real problem. Illinois has been a population sink for years. What we may be able to do for some species with these burnings is turn a population-sink situation into a population source and have these species become locally self-sustaining.
"It appears that planned burning may be a step in the right direction for certain species," Brawn said. "I fully expected to add to a large database that says highly fragmented agricultural landscapes are bad for birds. Well, we found that they are doing better in the areas of restoration burns."