Defining Success with Bog Turtle Conservation in Tennessee
By Bern W. Tryon
The beautiful little bog turtle, seldom reaching four inches in shell length, is the flagship species of a rapidly disappearing and imperiled ecosystem. In the south, bog turtles are an upland species primarily restricted to mountain bogs, open, spring-fed wetlands in the Blue Ridge and upper Piedmont sections of five states. The habitat is often flush with species of flora and fauna that may be found nowhere else. Despite the fact that bog turtles are considered Threatened or Endangered in all 12 range states and receive federal protection in the northern portion of this range, they continue to be in a range-wide state of decline, mostly due to habitat destruction related to the increase in development throughout these regions. In the south, 85 percent of all viable bog turtle habitat is located on private property, often associated with farming operations.
Our program got off the ground in May of 1986 when turtles were discovered in Tennessee in two small bog wetland sites in the extreme northeastern portion of our state in a section where the Blue Ridge hugs the state lines of both North Carolina and Virginia. Early on, with landowner permission and a permit from Tennessee Wildlife Resources Agency (TWRA), the 300 mile round-trip on a weekend day off was always worthwhile when one or two new turtles could be found and marked. The project expanded rapidly in the ensuing years with the establishment of partnerships between the Knoxville Zoo, TWRA, The Nature Conservancy of Tennessee, and numerous private landowners. In 2001, lead field technician Lynn Eastin, a resident of the study valley and now a part-time employee of both the Zoo and TNC, came on board.
Since then, the program has required five-to-six field days per week from April into November, and as the primary hands-on turtle people, it has become more than a full-time job for the two of us. Currently, 11 primary components now form what has become known as The Tennessee Bog Turtle Program. Although in some circles our work is known mostly from that carried out at the Zoo, just two of these relate specifically to captivity-based efforts.
The in-situ components include:
Ecological Studies of Bog Turtle Populations in Natural Sites
Since 1986, population demographics have been a focus, and the discovery of two small satellite wetlands containing turtles in 2002 and 2003 made this a lot more interesting. To date, over 2,300 captures have been made from these four valley sites. Although 110 bog turtles or their remains have been found, recaptures indicate that 89 turtles in a rather equal sex ratio are known or thought to remain in the valley. Based on the longevity of this study, half of this number is of a known age of 33 years or less, while the other half exceeds this age, some by a long way. Turtles can live a long time.
Radio-Telemetry to Document Turtle Movement and Habitat Use
In 2001, the program made an important move with the incorporation of radio-telemetry, and the results have been outstanding. From inception to date, 48 turtles have been tracked season-long for one-to-eight years. Although our mountain-climber was the most remarkable, moves of half a mile or more seem rather common for some turtles. Telemetry has shown that tracking some turtles for just a couple of years may well produce misleading information. Telemetry has identified turtle “greenways” and, in terms of bog turtles, the portion of the valley most critical for preservation.
Wetland Restoration Projects to Expand Bog Turtle Habitat
In 1997, The Nature Conservancy purchased large tracts of farmland adjacent to each of the two historic turtle sites for the purpose of returning much of this to former elegance. Based on our telemetry, this effort at one site has been remarkable, and much of the restored habitat has responded as have some turtles. Currently, seven telemetry turtles are using year-around what was for years a seasonally wet pasture.
Private Landowner Lease Program
Beginning in 2004, 15 acres of wetland and adjacent buffer areas have been leased by Project Bog Turtle, a non-profit, grassroots initiative based in North Carolina. This includes all property not currently owned by TNC at the two historic sites. These leases, though not legally binding, are meant as a thank-you to supportive landowners. Some of these folks have also received complimentary Zoo memberships, and Christmas cards are exchanged annually.
Local and Regional Educational Programs in Schools and Other Venues
Included in this have been various talks to local school groups, including those on Earth Day at the valley elementary school in which the students use radio-telemetry to find the “turtle.” In addition, the program has played host to a number of college biology classes, and most of these have contributed some volunteer work to the program.
This is mostly a “do as you go” effort and has included pruning out sections of invasive vegetation with the limited use of herbicides. Field technician-owned goats have been used at both historic sites for quality control purposes. Livestock grazing plays an important role in limiting natural succession in bog turtle wetlands.
Egg-Harvesting, Hatching, and Release
Based on the degree of egg and nest destruction noted along with the fact that little reproductive recruitment had been documented since about 2000, this project was initiated in 2006. With funding from an AZA CEF grant, an “Egg-Incubation Station” was constructed in the study valley, and this area was expanded in early 2008. In this three year period of time, 24 hatchlings have been released into their respective sites which may not have otherwise made it through the incubation period. This is thought to be one of the most important of our in-situ efforts, and it is one example of a “conservation tool” which may be considered for augmentation purposes.
Continued Search for New Bog Turtle Populations in East Tennessee
In the early years, much searching took place and other appropriate sites were found, albeit without turtles. Leads have been followed up, but lack of time has eliminated most additional survey work.
And now, a little about our captivity-based programs:
Captive-Breeding/Head-Starting of Bog Turtles at the Knoxville Zoo
In 1986 as well, the Zoo was given permission by TWRA to collect a small number of bog turtles for a captive-breeding effort. During the summer of that year, herpetology staff transformed what was once an outdoor alligator exhibit into The Southern Appalachian Bog. This peat-based, flowing system holds a wide variety of natural bog vegetation, and seven adult turtles were introduced in October of that year. Successful reproduction began in 1988, and to date over 150 eggs have hatched. The hatchlings spend their first winter indoors in a “Minibog” for some head-start growth, and as spring arrives they are moved outdoors into a “Rearing Area” where they spend a full year which includes an initial hibernation period. The year outdoors is thought to be essential to future survival.
Experimental Bog Turtle Release Project
Once captive-breeding was underway, the Zoo, TWRA, and TNC began discussions about an experimental release program in our state. The chosen site had been identified in 1986 based on its size, quantity of optimum habitat, and although less than 15 miles from the nearest North Carolina turtle site, a natural turtle population did not exist. With the blessing of the private landowner family, the first release took place in 1991 and to date, 129 captive-bred turtles in addition to 11 others from harvested eggs, have been liberated at this site. A few recaptures were made in the early years, but work here was intensified in 2001 and from then to date, over 500 recaptures of 57 turtles have been made.
Telemetry since 2002 has indicated that turtles have acclimated well to their home, and although several have moved from one defined release area into another, most have remained within or very close to their initial areas of release. Six deaths have been recorded, but survival rates appear to be rather acceptable. In 2008, two females developed eggs, and on 30 September, a hatchling was found walking in a small trail. It was the first documentation of successful reproduction in this release population, and it provides much optimism for the success of this experimental project.
The final component is in a sense the Mission Statement of our program: Assisting to facilitate the permanent protection and long-term viability of bog turtles and their habitat in Tennessee. Much remains much to be done, and there is no defined end-point in sight. It is a labor of love for a unique little species, and if it had not been for the ever-strong and continuing support of all of our partners, we would not be where we are today. Success in any long-term conservation program is often very difficult to define, but as we enter our 24th turtle season, the future appears rather bright for bog turtles in Tennessee.
Bern W. Tryon is the Director of Animal Collections/ Herpetology at the Knoxville Zoological Gardens