Remnant Grasslands of the Fayette Prairie, Texas

摘要: Twenty-five remnant grasslands from across the Fayette Prairie of SE Texas were sampled for species frequency and basal cover as well selected soil topographic properties. Polar ordination was used to elucidate stand patterns plant-environmental interrelationships. Three major topo-edapho-vegetation complexes defined. Upland clay soils (Vertisols Mollisols) characterized by Andropogon gerardii var. gerardil, Bouteloua curtipendula Carex microdonta. sandy loam (Alfisols) had Paspalum plicatulum, Coelorachis cylindrica Fimbristylis puberula characteristic species. Schizachyrium scoparium frequens Sorghastrum nutans ubiquitous dominants or codominants in all upland communities. Panicum virgatum Tripsacum dactyloides dominated lowland (Vertisols). The should be classified a southern extension True Grassland Association. INTRODUCTION is located (Fig. 1). It isolated Blackland N Coastal S narrow strips Post Oak Savanna. To E it borders on southeastern Evergreen Forest (Braun, 1950) W grades into South Plains (Godfrey et al., 1970). once contained approximately 1.5 million ha native grassland 1970), but little undisturbed vegetation remains (Johnson, 1931; Launchbaugh, 1955). No quantitative analysis exists area and, result, available data are insufficient adequately describe classify prairie. purpose this study to: (1) provide ecological soil; (2) relate differences vegetational composition edaphic factors, (3) evaluate affinities determine appropriate classification STUDY AREA flat gently rolling topography. Two rivers, Brazos Colorado, cross area. Uplands historically prairie although Quercus stellata Q. virginiana occurred occasionally scattered individuals small clumps. Lowlands stands hardwood forest including stellata, Ulmus crassifolia, Fraxinus spp. Carya illinoiensis. Current land use primarily tame pasture with limited cropland. Geologically, consists material deposited middle upper Miocene (Geol. Atlas Tex., 1974). formations occur: Fleming, Oakville Sandstone Cook Mountain Fleming formation underlies most except western margin. Laid down Miocene, 400-m-thick layer calcareous silty sediment some medium coarse grained sandstone. slightly older. found strip NW side S-central portion prairie,