Suther Prairie: Vascular Flora, Species Richness, and Edaphic Factors

Abstract

Piedmont prairie communities of the southeastern United States were common prior to European settlement. Suther Prairie in Cabarrus County, North Carolina is among the best-known examples of such an ecosystem. This study provides a complete floristic list of species observed at the site from 1997–2007. Sampling over the 10 yr period included fixed transects and general floristic inventories. During the 2006–07 growing seasons, additional transects and 90 randomly placed 1 m2 quadrats were established for sampling species frequency. Soil in six of these random quadrats was sampled at three depths (0–10 cm, 11–20 cm, 21–30 cm) for pH, organic C, total N, and extractable P, K, Ca, Mg, Zn, Mn, Cu, B, and Na.There were 208 species documented during the 10 yr sampling period. In 2006–07 142 new species were identified, but 49 previously documented species were not re-located. Of the 208 species, 66 were graminoids (36 grasses and 30 sedges/rushes). Ninety of these had previously been reported from prairie habitats. Obligate or facultative wetland species comprised 32% of the list. Thirteen species were rare, watch-listed, or uncommon for North Carolina. Big Bluestem (Andropogon gerardii) and Eastern Gamagrass (Tripsacum dactyloides var. dactyloides) had the highest frequency of occurrence during the 2006–07 sampling. Species richness was 6.8 species per m2. Levels of Ca and Mg were much higher than normal for Piedmont soils, and there was significant variation in soil C, N, P and Zn levels among the sampled depths.