[Truncated abstract] Most ecological research investigates the demography of organisms, which can be summarised by their population dynamics and structure. Population dynamics are the rates of birth, growth, reproduction and survival of individuals, which determine the number of individuals in different stage classes, or, the population structure. Understanding the demography of organisms is particularly difficult, and requires the application of different methods of investigation. A number of methods of investigation are required because each can only investigate particular aspects of population demography, and is subject to problems of inaccuracy and bias. Thus, population demography is best understood by simultaneously collecting complimentary data using different methods of analysis to quantify how and why the dynamics and structure of populations change with their environment. The need for complimentary methods of investigation to understand population demography is even greater for organisms that have complex life histories, such as corals. The life histories of corals are particularly complex because they display a variety of modes of sexual and asexual reproduction, and their rates of growth, reproduction and survival are strongly influenced by the size of the individual, which can change rapidly. Additionally, the rates of sexual recruitment to populations of corals are notoriously variable in space and time. Thus, corals are an ideal model to investigate the usefulness of combining methods of analysis to better understand the demography of organisms. In this thesis I demonstrate that combining data from a number of methods of analysis provides a much better understanding of the demography of populations of the mushroom coral Fungia fungites that were exposed to contrasting regimes of disturbance. I used methods of analysis that produce unique and complimentary results, in the form of genetic, size-structure, life history and experimental data. Genetic data confirmed that I was correctly identifying life history stages of polyps, indicated the extent to which a stock-recruitment relationship existed between the sexual recruits and the adult polyps at each population, and provided an estimate of the relative contribution of asexual recruitment to population maintenance. Changes in the size-structures of populations were quantified to determine the effects of different regimes of disturbance, and these changes in population structure were explained by quantifying the life history traits of polyps and their rates of transition through their life cycle. An experimental manipulation was conducted to specifically quantify the effects of sedimentation on the rates of survival and asexual recruitment of polyps, because sedimentation was an important disturbance whose effects were confounded by additional variables. Together, the set of complimentary data provided a good understanding of population demography in the context of varying levels of exposure to certain disturbances, and enabled the best possible predictions about the future of each population under a variety of conditions
| Identifer | oai:union.ndltd.org:ADTP/221129 |
| Date | January 2005 |
| Creators | Gilmour, James Paton |
| Publisher | University of Western Australia. School of Animal Biology |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright James Paton Gilmour, http://www.itpo.uwa.edu.au/UWA-Computer-And-Software-Use-Regulations.html |
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