Virginia spiraea (Spiraea virginiana) is an endemic shrub of the southern Blue Ridge and Appalachian Plateau Physiographic regions. This species has a scattered distribution throughout seven states and is federally listed as Threatened. In North Carolina, S. virginiana is listed as Endangered and is known to occur in five counties in the mountains. Spiraea virginiana is considered an early-successional specialist restricted to a narrowly defined niche, which includes natural disturbance. This shrub is most often found along river banks of high-gradient rocky streams that regularly flood, but it also occurs on right-of-ways that are regularly mowed. The largest population of S. virginiana in North Carolina occurs on U.S. Forest Service land along US 129 in Graham County along the Cheoah River corridor. The North Carolina Department of Transportation (NCDOT) has a right-of-way easement from U.S. Forest Service along US 129 to control woody vegetation for public-safety purposes. Ten subpopulations of S. virginiana occur along the roadside of US 129, which are affected by long-arm mowing. As a result of on-going informal consultations with the U.S. Fish and Wildlife Service, NCDOT developed mowing guidelines to help manage and protect these roadside populations. The U.S. Fish and Wildlife Service recently expressed concern about the potential negative impacts of the long-arm mowing practices used by NCDOT. Currently, a Biological Assessment has been initiated by NCDOT to examine the impacts of mowing on S. virginiana along US 129. We propose to develop and perform a study in coordination with NCDOT, U.S. Fish and Wildlife Service, and the U.S. Forest Service to evaluate the effects of mowing on S. virginiana along US 129 in the Cheoah River corridor, to supplement the Biological Assessment. Our study will be a controlled experiment to examine current and alternative long-arm mowing practices that NCDOT could practically apply along US 129 to manage roadside populations of S. virginiana. We anticipate that 10 subpopulations of S. virginiana will be manipulated along a ca. 9 mile stretch of US 129, and monitored annually for three years. Results of this study will be used to develop practical mowing guidelines for NCDOT to utilize in their right-of-way management of S. virginiana. This information also will be provided to the U.S. Fish and Wildlife Service and the U.S. Forest Service. Improved and field- tested mowing guidelines should benefit NCDOT by eliminating staff time devoted to informal as well as potential formal Section 7 consultations, while enhancing the protection of this endangered plant.
