Grassland Vegetation of the Eastern Edwards Plateau

Abstract

The herbaceous vegetation of 35 sites on the eastern Edwards Plateau was sampled by measuring point cover of all species and analysed by a Detrended Correspondence Analysis (DCA) ordination. A gradient was found, from sites dominated by the midgrasses Schizachyrium scoparium and Muhlenbergia reverchonii, to sites dominated by the shortgrasses Stipa leucotricha, Bouteloua rigeidiseta, Hilaria belangeri, Aristida longiseta and Buchloe dactyloides. Slope, elevation and soil pH decreased, soil depth increased, and the soil type classification changed along this gradient. It is argued that this gradient corresponds to an ordering of sites along a moisture gradient, the steeper slopes being wetter than the flatter sites despite their shallower soils because water is available in crevices in the underlying limestone. This gradient probably also reflects more severe grazing pressure on the flatter sites in the past.