Lately we have been placing greater emphasis on getting Bog Learning Network members in the field together to share restoration and management experiences. Earlier this summer, our friends from Georgia hosted a few dozen members and showed some of their rare wetland restoration work. On October 21st, twenty-five BLN members took a day trip to Shady Valley Preserves in Tennessee. Members were able to see and hear about work to restore populations of bog turtles and Southern Appalachian Bog habitat, as well as the history of hydrologic restoration on the site and use of mitigation banking. While it is impossible to capture all of the discussions that occurred, the following is an attempt to summarize the trip for those that could not attend.
Shady Valley’s globally-rare remnant bogs were once part of a matrix of montane wetlands, mixed hardwoods and conifer forests. The Valley’s forests were largely cleared by the early 1900s, and in the 1960s about 98% of the wetlands were drained to facilitate farming. Some islands of bog habitat were left and are now home to several species often associated with wetlands in the higher latitudes like cranberry bogs. Since 1978, The Nature Conservancy has prioritized work in Shady Valley to protect remaining bogs, restore wetland hydrology, and protect unique habitats for plants and animals.
We stopped in the morning at Orchard Bog Preserve, and following an orientation from TNC’s Director of Protection, Gabby Lynch, she and staff from the Knoxville Zoo told us a little about the preserve’s monument dedicated to Bern Tryon. Bern was the Knoxville Zoo’s Director of Herpetology and was instrumental in the preservation and survival of endangered bog turtles in East Tennessee.
Michael Ogle and Lynn Eastin from the Knoxville Zoo both talked to us about Bern and the bog turtle population monitoring and habitat restoration. The bog turtle is the most famous of Shady Valley’s rare species and occurs on two of the four TNC preserves. The Knoxville Zoo has dedicated over 28 years to researching Shady Valley’s bog turtle population. Orchard Bog is divided into 6 management zones and we discussed Orchard Bog Core, a 1.8-acre site where bog turtles were discovered in 1986. At the time, it had a relatively high density of turtles due to presumably good nesting, wintering, and adjacent foraging habitat, and likely served as a population source for the greater bog complex. This site requires management to prevent encroachment of multiflora rose (Rosa multiflora) and reed canarygrass (RCG; Phalaris arundinacea).
Lynn Eastin says that as early as the 1950’s, locals recall seeing small turtles as they were harvesting timber in the bogs, and many recount various interactions with bog turtles through the years, yet the first scientific documentation didn’t occur until 1986. Since then, visual searches, probing, trapping, and radio telemetry have led to the discovery of 89 individuals and increased understanding of the turtle movement and habits. They have found that turtles can travel 0.25 miles while foraging, and regularly make moves of 0.5 miles. According to Lynn, at least two turtles were tracked for over 2 miles up and across mountains. Over the past 15 years staff have documented very little natural reproduction among the bog turtle population. At this time the efforts at hatching eggs and releasing hatchlings, and captive rearing and releasing yearlings has documented relatively little success in survival.
One of the major management challenges at Shady Valley’s preserves is control of RCG. Staff first noticed it following the very first hydrologic restoration work at Orchard Bog in 1997. Although no one knows exactly where and how RCG seed entered the wetlands, possibilities include water- or wind-dispersed seed from adjacent lands, seed carried in on the wheels and tracks of restoration and/or farming equipment, or the RCG seed bank existed on the farmland, so when tillage ceased and the hydrology was improved, it began growing again. Regardless,
RCG is an aggressive, rhizomatous, perennial grass that can reach 3-6’ and form dense, monotypic stands. These stands are too dense to provide optimal cover for wildlife (although bog turtles are using RCG-dominated zones), few herbivores find it palatable, it outcompetes native plants, changes hydrology, and it eventually outlasts native seed banks. Perhaps foremost among the lessons taken from the Shady Valley trip is that it’s very important to detect and eradicate this plant as early as possible. Once established, RCG is difficult to control because it spreads rapidly by rhizomes.
One of the more significant discussion points for the day regarded TNC’s Shady Valley Preserves and their role as a mitigation bank. According to Sue Cameron, staff from the US Fish and Wildlife Service Ecological Services office in Asheville and Gabrielle Graeter (NC Wildlife Resources Commission) has been involved in restoration planning for a site in Alleghany County, NC. The site contains some remnant meadow habitat, and Sue feels it has potential for bog turtles. While mitigation projects frequently can be geared more towards establishing hardwood swamp forest regardless of what is appropriate for the site, Gabby provided insight regarding how the banking was done at Shady Valley. They were able to use wet sedge meadow/meadow bog (Schafale and Weakley 1990) as reference type, worked with planners to plant appropriate shrubs such as silky dogwood and silky willow rather than maples and sycamore, and developed appropriate success criteria. Since the field trip, Gabby has provided Shady Valley’s Mitigation Bank Instrument, which Sue plans to share with the project planners for the Alleghany Co. site. Sue is hopeful that this will enable them to restore the site’s appropriate wetland vegetative structure and ultimately benefit bog turtles.
The afternoon was spent at Quarry Bog Preserve & Restoration Area. This is a 65-acre site that was heavily ditched, tiled, and drained. Wetland restoration efforts in this area began in 2000 when the property’s approximately 8,000 linear feet of drainage tiles were broken and/or removed where possible. Much of the Restoration Area contains dense herbaceous vegetation, including RCG. For the past two growing seasons, TNC has utilized cattle to knock back the RCG and break up the RCG mats by hoof action. The extent to which bog turtles utilize this habitat is poorly understood, due primarily to detectability challenges associated with excessively congested herbaceous vegetation. However, the Restoration Area lies directly in between the core bog turtle habitat at Quarry Bog and another nearby location.