Landscape development and dynamics of woody vegetation in a subtropical savanna parkland, 1941-1990 /
A study was undertaken in southern Texas to (1) evaluate two
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy Connect to the full text of this electronic book |
| Summary: | A study was undertaken in southern Texas to (1) evaluate two remote sensing techniques (ground-penetrating radar [GPR] and electromagnetic induction [EMI] as tools for detection of diagnostic subsurface features, (2) assess the uses of EMI for mapping subsoil heterogeneity, (3) document spatial changes in woody landscape elements form 1941 to 1990 and determine soil properties that might explain variation in plant community dynamics, and (4) compare development and dynamics of landscape vegetation components for the Mesquite Brushiand Preserve (NMP) with the La Copita Research Area (LCRA). GPR was not effective in delineating differences in soils and correlations between EMI readings and soil properties were low or non-significant. Even so, results suggest EMI can be useful for general research, survey and exploration applications. Landscape elements classified as woodlands and groves increased in area (1.0 and 1.30/o/y from 1941-1969 vs. 0. I to 0.3%/y from 1969-1990) on the LCRA. Upslope migration of woodland margins was dynamic in some areas but static in others. 'Soil properties were comparable across woodland-savanna boundaries. However, differences in soil conductivity along transacts spanning static and dynamic boundaries suggest edaphic factors may account for differences in boundary behavior. Expansion of landscape elements classified as groves was variable and it is proposed that patterns of grove expansion are a function of (a) the size and shape of coarse-textured inclusion which occur in an otherwise continuous argillic horizon and (b) time of habitation of these inclusion by woody plants. A net increase in areal cover in vegetation classified as woodlands (37 vs. 38%) and groves (128 vs. 5%) on the LRCA and the MBP. Densities of landscape elements classified as small shrub clusters and individual shrubs were more variable on the MBP than on the LCRA, and no consistent trends were observed. Grove size increased on the LCRA (362 M2 in 1941 to 825 M2 in 1990), and did not change on the MBP. The MBP appears to be farther along the process of succession from grassland to woodland than the LCRA. This may reflect site specific differences in historical grazing practices or in topoedaphic constraints. |
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| Item Description: | Vita. "Major Subject: Range Science". In title, numerals are used. |
| Physical Description: | xiii, 92 leaves : illustrations, maps ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |