NatureServe Ecological System
National Vegetation Classification (NVC) Associations:
Moulton and Tennessee Valley Limestone Hill Barrens [Juniperus virginiana / Schizachyrium scoparium - (Andropogon gerardii, Sorghastrum nutans) - Silphium (trifoliatum, terebinthinaceum) Wooded Herbaceous Vegetation] --- Global Rank = G2
Tennessee Vegetation Classification Report:
Xeric Limestone Prairie, Cedar Barrens
Western Valley of the Tennessee River in portions of eastern Decatur, northeastern Hardin, western (mostly southwestern) Perry, and northwestern Wayne counties.
This community is restricted to the Western Valley of the WHR and all examples are found on the tops and sides of hills that flank the Tennessee River Valley to the east and west. Most occur within 2.5 mi of the Tennessee River but some are found up to 5.5 mi from the River. Most examples occur between 415-475 ft above sea level but some occur as low as 375 ft and some as high as 590 ft. Slopes range from level to steeply sloping (0-40 percent). Level areas are confined to summits, side benches or flats between adjacent slopes. Rock outcrops are common as are eroded gravelly patches. The outcrops are formed of a variety of Silurian-aged limestones, some range from greenish-gray to reddish and they are extremely rich in fossils. Soils are mostly clayey and calcareous.
This community is likely maintained by a combination of edaphic factors, including: the presence of shallow, gravelly, drought-prone soils underlain by limestone bedrock; soils with high clay content and with shrink/swell properties depending on moisture; relatively strong slopes that tend toward xeric in summer-fall. In the past, ground fires may have been important in periodically burning through this community. Fires would have been especially important in the adjacent woodlands.
This is a small patch community dominated by perennial grasses and forbs. It occurs as small to large openings among juniper-oak-hickory woodlands and there are usually numerous shrub islands or scattered stunted trees within this community. Vegetation height ranges from <0.2-2 m except for tree/shrub islands where vegetation can reach 10 m. Cover varies from dense to relatively sparse depending on the amount of exposed rock outcrops.
This community includes 7 major variations: (1) woodland edge and tree/shrub islands; (2) tall-grass zones; (3) short-grass zones; (4) limestone glade; (5) limestone glade seep, swale, and streamside; (6) eroded gravel slopes; and (7) outcrops. Of course not all examples have all subtypes. See component associations.
Ridge and Valley Dry Limestone Savanna
Ridge and Valley Dry Limestone Barren
Southern Cumberland Plateau Escarpment Dry Limestone Barren
Western Valley Dry Calcareous Woodland
Western Valley Limestone Glade
Western Valley Limestone Glade Seep
The presettlement distribution of this community very likely coincides with the areas of shallow, exposed gravelly hillslopes. It is likely that this community was more abundant in the past when fires were more frequent and adjacent woodlands would have been more open. More work is needed to determine potential area and amount of existing acreage.
Logging of surrounding woodlands. Damage of sensitive soils by ATV, jeep, tractors, and bulldozers. Grazing by livestock. Mining of limestone.
Decatur Co, TN.: Nine-Acre Glade, Gumdale Glade, Carroll Cabin Barrens State Natural Area.
- DeSelm, H. R. 1988. The barrens of the western Highland Rim of Tennessee. Pages 199-219 in: D. H. Snyder, editor. Proceedings of the first annual symposium on the natural history of the lower Tennessee and Cumberland river valleys. Austin Peay St. University, Center for Field Biology, Clarksville, TN.