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Title: The organization of complex ecological structures : a study of the functional role of heterogeneity in the formation of hierarchically structured populations of Canada geese Branta canadensis (Linnaeus 1758)
Author: Close, Andrew John
Awarding Body: University of Newcastle Upon Tyne
Current Institution: University of Newcastle upon Tyne
Date of Award: 2009
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The translocation of organisms to new bio-geographical regions has significant and negative impacts upon native biodiversity and socio-economic development. Biological invasions are dynamic multi-step processes. In order to alleviate the impacts attributed to the introduction of non-native species, it is essential to understand the processes that determine the outcomes of each step of the invasion process. Recent studies argue that environmental heterogeneity is fundamental to the outcome of each stage of the invasion process. Indeed, environmental heterogeneity has been shown to increase the invasive potential of non-native species. Heterogeneity is defined as the condition of diversity and non-uniformity of structure and is found throughout complex and dynamical biological systems. It can be categorized into two discrete forms; endogenous and exogenous heterogeneity. Interactions between endogenous processes and exogenous factors generate ecological patterns and structures that demonstrate distinct spatial and temporal signatures at multiple and contrasting scales. This study examined the functional role of heterogeneity in the formation of complex scale-dependent ecological structures within an invasive non-native species system, namely of Canada geese Branta canadensis (Linnaeus 1758). A graph theoretic approach was used to quantify the degree of connectivity within the study system. Findings indicated that the underlying complexity in the distribution of ecological patterns and structures was best explained by two theoretical models previously described in the literature: the small-world effects models and the scale-free graph.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available