Gary Walker, a professor at Appalachian State University, spoke on cliff face ecology in the Southern Appalachians. Walker caught my attention right away when he explained that cliffs are a relatively new and unexplored frontier for botanical research due to their difficult access.
Walker and his students have been on the cutting edge of this research in the Linville Gorge, the White Rocks at Cumberland Gap and the Obed River Gorge in the Big South Fork Wilderness. These areas contain relict plants, disjunct populations of species from the far north. And even more amazing, some of these cliffs host the oldest of the old growth forests in the southern mountains.
The northern white cedar and associated plants are relict plants from the last glacial age, found today in Canada, and on a few rock faces in the southern mountains. Growing alongside the northern white cedar is the showy lady slipper, a huge boreal bog plant with saucer-sized blooms, and not growing in the south except on a few cliff faces.
The same cliffs might be the last place you would look for old growth forests, but the northern white cedars, relatively small, gnarled, bonsai-like trees are ancient. Walker examined one such tree and found it was over 600 years old.
Research is revealing how the composition of botanical communities changes greatly from the top to the bottom of a cliff face. A great variety of plants that thrive on the rim of a cliff are not present on the vertical face.
The populations on the cliff face are a factor of more limited exposure to light, buffering from temperature extremes, thin or no soil, little root space and limited competition from other plants.
White Rocks, Cumberland Gap
On the talus at the base of cliffs you find plant communities of an entirely different mix compared to those on the face and the rim.
Because the study of cliff faces is so new, Walker’s students have been discovering new species of plants and animals, including many microscopic arthropods and gastropods on the walls of Linville Gorge. According to Walker, those gastropods viewed under a microscope have as wide a range of colors and shapes as a fine collection of sea shells.
The current state of cliff face research owes something to the difficult balance between outdoor sports and natural preservation. Rock climbers have an impact on the ecology of cliff faces by using brushes to scrape away lichens, moss and other plants in their path. While some species suffer, crustose lichens thrive in the wake of climbers, because they adhere to the rock more tightly than other species and thus resist being scraped off. With their competitors removed, the crustose lichens flourish.
Obed River Gorge, Big South Fork
Due to the popularity of rock climbing, park officials have been required to evaluate the environmental impact of the sport and respond with effective management plans to minimize the destruction of rare and sensitive ecosystems. So this has been driving, and funding, much of the research on Southern Appalachian cliff faces. Qualified rock-climbing biologists can find employment these days.
On occasion, after research suggested that some areas needed to be declared off-limits, cries of protest arose from individual climbers and organizations representing the industry. On the other hand, at some locations, research is contributing to solutions that protect the flora and fauna while demanding only small changes in climbing methods or routes.
No doubt, adventurous biologists will continue to make more discoveries on the frontiers of biological research, the cliff faces of the Southern Appalachians.