The activities of competing wood decay fungi bring about the decomposition of deadwood. The rate of decomposition is determined by the community composition, which is shaped by competitive interactions. Fungi compete with one another for territory and resources within 3 dimensional space via the production of an arsenal of inhibitory chemical compounds, yet interspecific interactions and chemical warfare within communities have never before been studied in 3 dimensional resources. This thesis, therefore, aims to determine how interactions cause metabolic processes to change, and, by the use of novel 3 dimensional systems, how those processes are affected by increased species diversity and spatial heterogeneity. Overarching hypotheses which have driven investigations are: (1) secondary metabolism and interaction outcome are inherently linked, both of which are affected by environmental conditions, (2) changes to spatial distributions and increased species diversity cause interaction outcomes and community dynamics to alter, and (3) changes to metabolic strategies for antagonism and resource utilisation will reflect alterations to community dynamics. Transitive interactions in pair wise 2 dimensional systems often became intransitive in species richer 3 dimensional systems, and the extent of patch fragmentation determined the length of coexistence of individuals within communities. Production of secondary metabolites comprising the fungal chemical weaponry, namely extracellular lignocellulolytic enzymes and volatile organic compounds (VOCs), was significantly different between 2 and 3 dimensional systems, between systems of varied species diversity, and between different spatial distributions of fungi, reflecting the observed changes to community dynamics. Furthermore, the production of intracellular metabolites which function in the biosynthesis pathways of antimicrobial compounds and agents of decay, was affected by species diversity, spatial distributions and territory fragmentation. Additionally, secondary metabolism and interaction outcome were found to be inherently linked, and affected by abiotic conditions. Specifically, interaction outcomes changed under different temperatures, and when wood was pre colonised for different lengths of time. Changes to the production of both enzymes and VOCs reflected the different outcomes, as either the cause or effect of outcome changes. These conclusions not only confirm the thesis hypotheses, but also demonstrate the importance of environmental conditions, species diversity and spatial dynamics to fungal community dynamics and forest ecosystem functioning.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:742895 |
| Date | January 2018 |
| Creators | O'Leary, Jade |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/111801/ |
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