H. Mae Kile, Joey Shaw, Jennifer Nagel Boyd
Southeastern Naturalist 12 (1), 99-120, (1 March 2013) https://doi.org/10.1656/058.012.0109
Federally threatened Scutellaria montana (Large-flowered Skullcap) is a perennial herbaceous species endemic to southeastern Tennessee and northwestern Georgia. A large population of S. montana is located at the 648-ha Tennessee Army National Guard Volunteer Training Site (VTS) in Catoosa County, GA. Due to necessary operational activities that include vegetation clearing along site boundaries to maintain security and prescribed burning and overstory clearing to reduce fuel loads as a wildfire-prevention measure, S. montana individuals and groups at the VTS may be disturbed unavoidably at times. Our objectives were to provide recommendations for land managers at the VTS and elsewhere regarding the response of S. montana to transplantation when plant rescue is necessary and to guide site selection for transplantation by elucidating the effects of pre-transplantation burning and canopy thinning on transplant survival and subsequent success. We relocated 100 S. montana individuals in spring 2010 from a site scheduled for clearing to plots that were burned (B), thinned (T), treated with a combination of burning and thinning (B T), or not treated (C; control). Survival, growth, reproductive potential, development, and physiological measurements were used throughout the 2010 and 2011 growing seasons to evaluate the success of transplantation overall and in various relocation plots. At one year post-transplantation, 91% of the original transplants had survived relocation, and among all transplants, mean stem height and the numbers of stems, leaves, and flowers per individual significantly increased. Additionally, the percentage of total transplants that were juveniles was much lower one year post-transplantation than immediately following transplantation (5.7% vs. 27%), while the proportion that were reproductive adults was greater one year post-transplantation (37.5% vs. 22%). However, reduced survival was found in the canopy-thinned plots (84% in both plot T and plot B T) compared to plot B (100%) and plot C (96%) one year post-transplantation. The main effects of both burning and thinning included significant increases in stem damage and in the proportion of transplants that were vegetative adults, with an associated decrease in the proportion of reproductive adults. Combined, these findings may have resulted from increased trampling and feeding activity of vertebrate herbivores in burned and thinned plots. Overall, we considered our transplantation efforts to be successful due to high survivability and continued growth and development of individuals one year post-transplantation. However, to maximize the success of S. montana relocation, we suggest that transplants be relocated into unburned, unthinned forests and that vertebrate herbivory be subsequently controlled though the use of exclosures.