SIGHTLINE
WINTER/SPRING 2002
Vol. 3 No. 1
Crunching Numbers, Counting Bugs
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Editor: David Brill; Assistant Editor: Constance Griffith; Writers: Kris Christen, Lisa Byerley Gary, Elise LeQuire, Dennis McCarthy, and Becky Nichols. Graphic Designer: Lisa Byerley Gary.
SIGHTLINE is published on behalf of
Great Smoky Mountains National
Park
by the
Energy, Environment and Resources
Center (EERC)
at the
University of Tennessee.
EERC conducts research designed to promote real-world solutions to problems in the fields of energy, environment, technology, and economic development.
For additional information, write EERC, 311 Conference Center Building, The University of Tennessee, Knoxville, TN 37996-4134, call 865-974-4251, or visit our Web site at http://eerc.ra.utk.edu.
SIGHTLINE is sponsored by:
and
Field and Stream
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Cades Cove's unique history and ecology make it home for an unusual variety of plants and animals.
BY LISA BYERLEY GARY
In Great Smoky Mountains, the most-visited of all national parks, Cades Cove offers a special attraction all its own. Of the 9 million or so visitors who make their way to the Park in a given year, fully 2 million of them take the meandering 11-mile loop through the Cove.
One of only a handful of open spots in the vast and heavily wooded Smoky Mountains, Cades Cove has been home to humans for hundreds of years and was claimed as a hospitable niche in the mountains by European settlers in the 1820s. Here, nestled into the bosom of the hills, they prospered as farmers of fertile soils and hunters of abundant game, despite the wild and rugged terrain around them.
The settlers and their descendants are gone now, but the Cove is still a hospitable abode for many species of flora and fauna. An array of wildlife in the open fields along the Cove road is one reason so many human visitors drive, bike, or hike through the Cove each year. And plants abound here that are found virtually nowhere else in these mountainssome, in fact, that are found nowhere else for hundreds of miles. Such plants seem to thrive on the limestone of the Cove's soil.
Back to Nature
Managing this fertile and historic valley in the Smokies is a challenge. When the Park was established in 1934, modern
management techniques involved human-made "improvements" such as the introduction of exotic plant life, the building of ditches, and the draining of wetlands. This strategy continued throughout the 1950s and 1960s. Today, some of the Park's management of Cove lands involves undoing some of those old remedies and reverting to native species and natural landscapes.
But knowing what is "natural" and "native" involves evaluating what is there and watching for trends among animal and plant species. To that end, Park scientists undertake formal and informal counts of plants and animals.
UT wildlife scientist Michael Pelton counted deer in the 1970s and 1980s using a technique called spotlighting, which the National Park Service's Bill Stiver and co-workers continue to use today. Every second week throughout the year, they drive along the Cove's loop road about 30 minutes after sunset shining a spotlight on both sides of the road. They count and record the number of deer they see, then compare the data with that of previous years. A modification to this technique will help translate a simple head count to a more precise deer-per-acre or deer-per-square-mile density analysis.
"Not many people go out in the Cove at night," Stiver says. "But there is a lot going on at night that people never get to see."
Park wildlife biologists note other sightings on their
nighttime forays as well. Raccoons, skunks, wild hogs, barn owls, and bears are frequently on the list. The Cove is home to many more species, including river otter, groundhog, gray squirrel, Eastern cottontail rabbit, chipmunk, bobcat, copperhead, and timber rattlesnake.
"The Cove is a very diverse area," Stiver explains. "A lot of edge-type species can exist there. The old field-type settings offer a variety of habitat that lends itself to a variety of animals. Most of the land in the Park is forested, so these open habitats provide unique space you don't see otherwise. There are species of hawks and birds you don't see in other areas of the Park. And the deer population is much higher than anywhere else in the Park."
Deer in Decline
The deer like to graze in the Cove's open spaces and are prolific there, but the current population is markedly smaller than in previous years.
"Spotlight counts in the 1970s routinely produced 300 deer," says Stiver. "We're lucky to get 100 now."
That is not necessarily a bad thing, he says, because the Cove's smaller population of deer is now stable and healthy. He knows this because, in addition to the spotlight counts, five deer are harvested every second year to evaluate the herd from a health standpoint. Weight checks and parasite counts indicate the level of stress on deer in the Cove. Recent evaluations indicate that the deer herd is within the Cove's carrying capacity.
While it's hard to be sure why the deer herd has dec-lined in the last few years, scientists have their suspicions, says Joe Clark, research ecologist with the U.S. Geological Survey's Southern Appalachian Field Laboratory. "For one thing, you see a pretty definite browse line in the woods where deer have eaten all the foliage. You can see through the woods really well, which is unusual for the Park."
That, says Clark, means there is not a lot of cover in the trees, and that may affect deer densities. The deer give birth to fawns in May and June, he says, and they count on camouflage for defense.
"The lack of an understory leaves the fawns vulnerable to coyotes, black bears, and bobcats," Clark says. "So fawns don't make it to adulthood very well. Enough make it for the population to be stable, but there are less deer than there would be with heavier cover."
Another impact on the deer population is the lack of major predators for adult deer, Clark says. There are no wolves or mountain lions in the area now, and hunting is not allowed in the Park. While other predators would gladly eat an adult deer, they don't often get the opportunity. So the adult deer thrive, and heavy populations of adults consume the vegetation needed to sustain a herd. Lack of food triggers a decline in the adult population.
Coyotes as Predators
In the past, the red wolf was the dominant canine in the Smokies, Clark says. Today the coyote, which moved into the area in the 1980s after migrating from the western United States, has largely occupied the ecological niche once held by the red wolf. "There are some differences, of course. The coyote has a somewhat smaller body size, but there is a lot of dietary overlap. They play some of the same roles."
The black bear, too, is a carnivore and will prey on fawns and other small mammals at times. Clark, a noted bear researcher, says that many bear sightings in the Cove come in the spring when bears are searching for fawns. Still, the black bear is predominantly a fruit-and-nut eater. "The bears do benefit from clearings in the Cove. There are black cherry trees adjacent to large cleared openings that bear fruit pretty well," he said. "August and September are good times to see bears in trees eating fruit."
Bears come to the Cove not because they can't find cherry trees elsewhere, Clark says, but because the trees in the Cove may bear more fruit because they get more sunlight.
Plant Species
The Cove used to be a fertile home for farmers largely because of its unique limestone soil composition. Cades Cove and White Oak Sinks, a much smaller area, are the only two zones in the Park that feature that type of soil. As a result, the Cove boasts a mix of plant species uncommon to the larger Park area, says botanist Janet Rock. There are some two-dozen species found only within the Cove. Part are there because of the limestone, but there are other anomalies no one has really studied, Rock says.
One fascinating aspect of Cove flora is the coastal plain disjuncts found there. These species are unique not only to the Park, but to the entire region. "You'd have to travel to the coastal area of Virginia or the Carolinas to find plants like those," Rock says.
Why coastal plain species reside in the Cove and how they got there are questions no one can answer, Rock says, but they are considered native plants and were not introduced by settlers. The Cove's coastal-plain plants include Virginia chain fern, weak-stemmed buttercup, and campanulate (bell-shaped) sabatia, a colorful pink flower.
Other unusual flora in the Cove include yellow-eyed grass, which is a marsh plant, and hyssop and bladdernut, which are limestone-tolerant plants.
Rock monitors populations of rare and unusual plants in the Cove. "That can mean as little as checking on them to make sure they're still there or as much as actually counting plants specifically," she says. "We put the numbers in a database and eventually graph and analyze the data to keep track of increase or decline. If there is decline, we consider management action."
Native Indian grass grows again in Cades Cove. Photo: National Park Service
Natural Processes
The Park Service's management plan includes restoring not only natural plants but natural processes as well. Fire can be used as a tool to accomplish this, as can taking action to allow wet areas to continue to be wet, a reversal of former management schemes that sought to drain wetlands.
Until a couple of years ago, the Park leased land in the Cove to farmers for pasture or hay crops to discourage growth of trees and keep open areas open. But when a major lessee decided not to continue a 600-acre grazing lease, Park biologists decided to re-evaluate, says Jenny Beeler, a biological science technician with the Park's Vegetation Management Division.
"What we proposed was to make smaller fields, which present a patchwork appearance like aerial photos we have of the Cove from 1936. Now, we have 60- to 100-acre fields that have become consolidated. Since there isn't a patchwork pattern today, we proposed to try and break it up a little bit," Beeler says.
That doesn't mean fields will be allowed to grow over or that the Cove will lose its distinctive open space, she says. The Park will keep open areas but will do so in ways that are more natural and/or better for the native plants and animals.
"Some fields may be burned on a rotational basis to keep them clear, while others will be mown," Beeler says. "But we will mow only once a year, in October, which would be better for ground-nesting birds and for fawns than doing it twice a year."
Natural Grass
Eventually, Park biologists hope to re-establish native grasses in fields now growing fescue, a non-native grass. Cove farmers introduced not only fescue, but Timothy grass, Johnson grass, velvet grass, and foxtail grass, as well as red and white clover. Other exotics, such as horse nettle, dandelions, and wild onions, were probably introduced accidentally.
But even a worthy idea like bringing back the grasses that once grew in the Cove must be executed carefully, Beeler explains. "We have a mandate not to bring in plant and seed material from outside the Park, so I can't go to Missouri and buy plants that were once native to the Cove. We want to protect the genetic integrity of our own species. If we want to restore natives, we have to collect seed from the Cove itself."
That is a painstaking and time-consuming process.
In the west end of the Cove is an old field that hasn't been cultivated in 15 to 20 years, Beeler says. "There are pretty good populations of native meadow grass in this field. We have big blue stem, little blue stem, and Indian grass."
Starting in 1995, volunteers began to collect seeds from these grasses by hand. The seeds were then replanted in small fields for cultivation. Once the single-species fields were established, a tractor-drawn harvester could be used to harvest seed.
"Now we can get in an hour what it would take 10 people two weeks to collect by hand," Beeler says.
She hopes to start restoring fields using the Cove's own native grass and wildflower mix in the next year or two. That will be done with a no-till seed drill that won't require disturbing the soil for planting. Beeler has established a demonstration plot that is open to the public about 100 yards or so from the Loop Road Cades Cove overlook.
Native Superiority
The native grasses will be good for diversity and for Park wildlife, Beeler says. Exotic grasses like fescue tend to mat as they grow, which isn't good for small mammals or ground-nesting birds like quail because they can't maneuver through it, she says. Native warm-season grasses, however, are bunch grasses; small openings between the bunches facilitate wildlife movement through the field and provide nesting places.
Other natives found in the Park include purple top, beaked panicum, broom sedge, and eastern gamma grass.
Even though the Cove's farming communities have disappeared, humans are still very much a factor in Cades Cove's ecological balance because of the large number of visitors. Plant specialists like Rock don't disclose the exact locations of rare plant life, fearing trampling and collectors. And animal specialists like Stiver are concerned about human impact on wildlife in the Cove environment, where people and animals often come too close to one another.
"Our problem is how to enforce rules on wildlife harassment," Stiver says. "Even defining what harassment is can be difficult. We're trying to define it in terms of distance.
"It's a difficult thing for rangers to control human-animal interactions. They can go and stand there and force everyone back from the animal being observed, but as soon
as the ranger leaves, the next group will come right up. The ranger almost has to stand there until the animal is gone."
Stiver wants people to realize that if animals change their behavior in the presence of humans, the humans are far too close.
Cades Cove and its open areas, fertile limestone soil, and water sources have been attracting animals and humans for hundreds of years. In fact, archeologists have discovered plentiful evidence that early American Indians lived and hunted in the Cove long before the first European settlers arrived.
"The people who settled the Cove recognized the area's unique qualities," Clark says. Today, some 2 million visitors per year do as well.
For more information, call Janet Rock at 865-430-4743, Jenny Beeler at 865-436-1707, or Bill Stiver at 865-436-1251; or write to them at Great Smoky Mountains National Park, 107 Park Headquarters Road, Gatlinburg, TN 37738.