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Media Contacts:
Dr. Ted Simons, 919/515-2689, or [email protected]
Kevin Potter, News Services, 919/515-3470 or [email protected]
June 8, 2000
Researchers Study Impact of Forest Disturbance on National Park Birds
FOR IMMEDIATE RELEASE
Scientists have long wondered whether undisturbed, ancient forests in the eastern United States offer better habitat for birds than forests that have recovered from logging. A team of researchers at North Carolina State University has determined that the answer is both "no" and "yes" - at least in Great Smoky Mountains National Park.
The NC State scientists found that all the bird species present in the park's undisturbed, old growth forest also were present in second-growth forests. But some species - including black-throated blue warblers and winter wrens - were less abundant in the areas that had been logged early during the 20th century.
The NC State scientists, led by Dr. Ted Simons, associate professor of zoology, will present their findings Sunday, June 11, at the Society for Conservation Biology's annual meeting at the University of Montana, in Missoula.
"In terms of the bird community, these forests can recover fairly well," said Simons, who is assistant unit leader in the North Carolina Cooperative Fish and Wildlife Research Unit at NC State. "This is the first time anyone has been able to determine that with this level of certainty."
Simons cautions, however, that the study covered only Great Smoky Mountains National Park, where forests logged 60 to 100 years ago have been protected since the park's founding in 1935. Comparing the bird populations in less protected areas outside the park with populations in the park might yield different results.
In fact, that's his next step: To compare bird communities in the park with those present on nearby privately owned lands and at Pisgah, Nantahala and Cherokee national forests. "Using the park as a control site allows us to look at questions of how bird communities change relative to changes in the environment," he said.
The NC State research could offer clues about why the populations of some Neotropical migrants - bird species that breed in the United States and Canada then migrate to more tropical climates for the winter - have been declining consistently for the last quarter century.
The 500,000-acre Great Smoky Mountains National Park is an ideal site to study bird communities in the eastern United States. Its diversity of breeding Neotropical migratory birds is among the highest of any region in the country. Straddling the North Carolina-Tennessee state line in the southern Appalachian Mountains, the park contains the largest continuous area of forest in the eastern United States. Additionally, about 20 percent of the park - or 100,000 acres - has never been logged or otherwise cleared, representing more than half of such forest east of the Mississippi River.
For four summers, from 1996 to 1999, 15 researchers led by NC State doctoral student Susan Shriner counted 74,797 birds of 115 species at 4,159 survey plots in the park. At each site, they also collected data on forest type; the level of forest disturbance; and environmental factors such as slope, elevation and exposure to the elements.
Then they compared bird populations at plots that were similar in all respects other than disturbance. Overall, they found that no old-growth species were absent from the second-growth sites. But they found that the individual old growth forest sites had significantly higher numbers of individual birds and of species present.
"These results demonstrate the importance of old-growth forests to the bird communities in Great Smoky Mountains National Park," Simons said. "As one of the few areas with significant old growth forests in the southern Appalachians, the park is an increasingly valuable resource for bird populations as more land surrounding the park is developed."
The park, Simons said, may serve as a "reservoir" for bird species that move to the public and private lands outside its boundaries.
National Park Service officials funded the NC State study because they are interested in whether the 100 bird species that breed in the Great Smoky Mountains can act as an indicator of the park's environmental quality. Specifically, they're concerned about the impact of air pollution, acid rain, nearby forest fragmentation and 7 million visitors per year on the park, which is the most visited in the nation.
Park Service scientists will use some of the study's plot sites for long-term studies of bird communities in the park.
During the Society of Conservation Biology conference, Simons and Dr. George Farnsworth, an NC State post-graduate fellow in zoology, also will present their research on mathematical models that aim to predict the reproductive success of songbirds. That presentation will be on Monday, June 12.
- potter -
EDITOR'S NOTE: To reach Simons during the Society for Conservation Biology conference, call conference organizer Jeanne Franz at 406/243-5272. Kevin Potter in the NC State News Services office also can relay messages to Simons and can provide reporters with an abstract of his presentation.
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