Composition, diversity, and interspecific relationships of grasslands within the True and Upper Coastal Prairies of North America.
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1983.
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| Subjects: | |
| Online Access: | Link to OAKTrust Copy Link to ProQuest Copy |
| Abstract: | No previous study has documented changes in soils and vegetational composition of grasslands across the entire True Prairie-Upper Coastal Prairie transect. Sixty-three relict upland grasslands were sampled along this transect in order to determine relationships among communities, species-environmental relationships, and trends in species diversity. Principal components analysis (PCA) and cluster analysis using thirty-five Texas stands indicated that four community-types could be recognized, and an additional three were identified based on data from previous studies for geographic areas and soil types not sampled. PCA and cluster analysis of all sixty-three stands indicated two community-types, one in the centrall part of the True Prairie and one in the north, could be recognized for sites north of Texas. The first axis from PCA corresponded to a south to north arrangement of stands along which mean temperature (r = -0.93 for correlation between stand position and annual minimum temperature) and precipitation (r = -0.89 for mean precipitation) decreased, while soil organic matter content (r = 0.82) increased. Average species richness increased and concentration of dominance decreased slightly from south to north, but no pronounced trend in diversity occurred across this broad climatic gradient. The ratio of C(,3)/C(,4) graminoids showed a sharp increase from central stands northward. Product moment correlations showed species which increased in the north, including Andropogon gerardii, Stipa spartea and Sporobolus heterolepis, were significantly negatively correlated with mean temperatures and precipitation and positively correlated with soil organic matter. Paspalum plicatulum, Schizachyrium scoparium and Sporobolus asper, species which increased in the south, showed the opposite relationships. Excluding two small northern Texas community-types, grasslands of the True and Upper Coastal Prairies should be viewed as a continuum, with Andropogon gerardii more important northward and Schizachyrium scoparium more important southward. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Range Science." |
| Physical Description: | xii, 155 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references (leaves 134-141). |