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Title: Animal body-size relationships : patterns, mechanisms and implications
Author: Leaper, R.
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2000
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The papers presented here represented an effort to investigate body-size relationships explicitly, using a variety of different approaches, scales of observation and empirical methods, and addressed issues pertinent to several aspects of food web theory, macroecology, and experimental community ecology. At the scale of the food web, (Paper I) the inclusion of parasites in the Ythan food web challenged previous empirical studies of predator-prey body-size relationships and the assumptions underlying food web models. Specifically body-size was neither the determinant of the trophic hierarchy of feeding links in the web, a key assumption in the cascade model and its variants, nor a constraint on the distribution of feeding links between individuals within the food web. Continuing the food web theme, but using a macroecological approach (Paper II), abundance body-size relationships reported in the literature were shown to be biased. Although the shape of the abundance body-size constraint space in the Ythan was broadly similar to the polyhedral shape reported for entire ecosystems, when the body-sizes of small taxa were included in the data set, the statistical relationship between body-size and abundance differed markedly from those documented for most other terrestrial and aquatic studies. At the scale of the marine invertebrate guild (Papers III and IV), an experimental approach demonstrated that the mechanisms proposed to generate patterns in body-size and patterns of re-assembly in benthic assemblages could not be rigorously supported. Specifically, habitat architecture was not as intimately related to body-size patterns as originally claimed, and the re-assembly of benthic communities was not driven by a directional change in organisms size. In both experiments issues of spatio-temporal scale made it difficult to relate patterns to underlying processes.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available