| Because of its large size, topographic diversity, and southcentral position in North America, Texas has a flora of some 5,480 species (Correll and Johnston, 1970) in 10 natural regions (Gould, 1975a) and at least 77 major plant associations (Diamond et al., 1987). Central in the state's biogeographic pattern is the Edwards Plateau, a strongly dissected tableland, distinctly bordered on the east and south by the abrupt Balcones Escarpment. The steeply-rising Scarp and high Plateau feature an array of limestone and granite outcrops plus permanently watered canyons, dry mesas, and broad valleys that add to natural diversity. |
| In April, 1984, we met on the Plateau at Junction, Texas, for a symposium that addressed the region's vegetation patterns and dynamics of pattern development. O. W. (Bill) Van Auken organized this session, sponsored by the Southwestern Association of Naturalists. Each participant, whose original contribution follows, lives and works on the Edwards Plateau or Balcones Scarp. Our collective aim is to provide an introduction to the vegetational landscape, including representative photographs, specific research about the history of vegetation patterns, and quantitative information on current structure and succession. |
| We have arranged the symposium contributions in general to specific order over a "gradient" of woodland-forest to grassland studies. The introduction by David Riskind and David Diamond is followed by a historical appraisal of woody versus grassy vegetation by Del Weniger and a floristic geography of woody and endemic plants by Bonnie Amos and Chester Rowell, Jr. Then, chapters by Bill Van Auken and Fred Gehlbach describe woody vegetation structure, including community-types, and infer succession in different parts of the region. The role of fire in structuring a woodland-grassland mosaic is examined by Paul Fonteyn, Wade Stone, Malinda Yancy, John Baccus, and Nalini Nadkarni, while interspecific dynamics of both woodland and grassland are observed by Norma Fowler. Finally, a unique record of grassland succession is summarized by Fred Smeins and Leo Merrill. (See Fig. 1.) |
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II. Gehlbach, Frederick R., 1935