TVA Rights-of-Way: Ruderal Habitats or Pre-settlement Savanna Conditions?

A bit of good news came from the Cumberland Plateau in May 2019, where the Southeastern Grasslands Initiative team is working closely with Adam Dattilo of TVA, Ashley Bennet of the Electric Power Research Institute, and JoVonn Hill of Mississippi Entomological Museum. SGI's team members include Theo Witsell, Darrell Brandon, and Zach Irick. The purpose of our work is to survey the flora and pollinator communities of 15 powerline right-of-way grasslands on the Cumberland Plateau.

Here are just a few of the findings from our first surveys:

Rose Pogonia (Pogonia ophioglossoides) rediscovered on the Cumberland Plateau: the state endangered rose pogonia was once known from probably 10 or more sites in the state based on herbarium records, including populations in the Blue Ridge, Cumberland Plateau, and Ridge and Valley. Since approximately the ‘30s, all of the Plateau populations have been lost due to bog/wet meadow destruction with some of the last observations coming from the 1980s. Adam Dattilo and Theo Witsell discovered a nice population of at least a couple hundred in a TVA powerline in Van Buren Co., which unless we are mistaken marks the first documentation of this species from the Plateau in a quarter-century!  Congrats to the Tennessee Valey Authority for good management of the power line corridor where this was found! (Photo left, Adam Dattilo).

Indian Paintbrush (Castilleja coccinea) found:  During our inaugural week of fieldwork for the 3 week project, within literally 5 minutes of being on the first powerline corridor in Cumberland County, we discovered Indian Paintbrush (Castilleja coccinea). Dwayne Estes was literally just telling everyone to "watch out for paintbrush" when Adam spotted paintbrush by the trail. Although this species isn't tracked as rare in the state of Tennessee, it is increasingly recognized as rare Southeast-wide (and really should be in TN in our opinion). Zach Irick visited another population in Van Buren County which is near a previously known population that has since been wiped out. There are only 2-3 occurrences of paintbrush known from the Cumberland Plateau and probably less than 10-15 for the entire state. (Photo right).

Bog Oat Grass (Danthonia epilis) found: Several populations of this rare grass occurred in acidic seepage wetlands we surveyed. This species look to the more common Danthonia sericea, which often grows in close proximity but in dry places. We've doubled the number of known occurrences for this species just in the past couple of weeks.

Dwarf Sundew (Drosera brevifolia) boasts new population. We found a new population of Dwarf Sundew, this one in Bledsoe County. It is likely only the 3rd record for the Cumberland Plateau surface. The first known population was found a few years ago at Catoosa Wildlife Management Area, and we revisited that one to find that TWRA's excellent management of the shortleaf pine savannas there is greatly benefitting this rare species and there were hundreds of these tiny plants on the ground.

Other Rarities: Other goodies we found in the power lines included Hypericum nudiflorum (recently added to rare plant list) and Juncus subcaudatus (found by Theo Witsell), which although not tracked currently, probably should be. 

This work highlights the critical importance of power line rights-of-way not just on the Cumberland Plateau but in many places throughout Tennessee and the South. Some of these lines, especially those managed by small utility companies, are routinely blasted with herbicide and rare plants, grassland habitats, and the animals dependent on them are constantly in danger of being lost. 

For decades we looked at power lines as ruderal or artificial communities, but in fact in places like the Highland Rim, eastern parts of western Tennessee, the Plateau, and a few other areas, these high-quality well managed power line corridors are the closest thing left to pre-settlement savanna conditions, minus the trees of course. 

Thanks to TVA for not only for supporting our work financially, but also to Adam Dattilo for leading this science-driven project. It speaks volumes to TVA's commitment to ensuring that sensitive species and communities within its system of corridors are cared for. At the end of this project, SGI will draft a publication with all team members that reports on the flora, vegetation, and pollinator fauna of these sensitive habitats.