Microscale impact assessment of the Dutch Deltaplan Reclamation Project using empirical modeling techniques /
| Main Author: | |
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| Other Authors: | , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1990.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | The possibility and criteria for the quantification of ecological principles, as a means to assess the environmental impact of the Deltaplan on the aquatic biota of southwest The Netherlands, were investigated. Examination of the experimental data for eight of the most common species of aquatic Hemiptera and twelve environmental components, collected from 498 randomly selected sample sites, produced a second order polynomial regression model in which two variables proved to be statistically significant and could be related to the imposed environmental change. Response surface analysis generated four different contour systems. Three diagrams were simple. The fourth represented a ridge and suggested the existence of a single compound variable. The derived logarithmically transformed chloride to calcium ratio induced the development of a macro-environmental gradient which, for the biotopes sampled, took on the form of a curve. Incorporation of spline functions in the polynomial regression equation resulted in an improved statistical fit and generated two cardinal points at which the slope of the regression line changed for all species of aquatic Hemiptera tested. The first critical value of approximately 1:1.225 indicated a point of deflection in the composition of species below which mostly transient species were found, while the upper ratio of 7.620:1 represented a deflection point above which only specialized insects were present. The range of ratio's in between was associated with a set of highly resilient organisms. An examination of the functional relationship between the intrinsically linear regression model and the classification of aquatic Hemiptera as indicator species suggests the usefulness of the derived spline properties as attractive criteria for the evaluation of ecological damage. For the execution and operation of the Deltaplan this translates into a potential harmful effect when the composition of the water changes so rapidly that the ionic make-up shifts from one extreme to the other without utilizing the intermediate stage as a jumping point for adaptation to natural change. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Civil engineering." |
| Physical Description: | xi, 148 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |