Doctoral Thesis
Cascading impacts of the plant pathogen Phytophthora cinnamomi to mycophagous quenda (Isoodon fusciventer) and native fungi
Doctor of Philosophy (PhD), Murdoch University
2024
Abstract
Phytophthora cinnamomi is a soil-borne plant pathogen that has caused plant species losses in woody ecosystems around the world. Phytophthora cinnamomi is suggested to alter fauna habitat, which may result in cascading impacts, but these topics are underexplored. A principal aim of my research was to investigate P. cinnamomi impacts in native jarrah forest, where the bandicoot ‘quenda’ (Isoodon fusciventer), a small mammal, forages for fungi (e.g., truffles), earthworms, and tubers by digging soil. I predicted that P. cinnamomi would reduce habitat for quendas and result in a shift in fungal communities across my study sites in the Shire of Mundaring, Western Australia.
Phytophthora cinnamomi infestations had lower shrub cover and densities of habitable grasstrees compared with adjacent non-infested areas of jarrah forest. Quenda foraging pit densities were reduced in P. cinnamomi infested forest. However, truffle densities were unchanged. I measured densities of small to large size classes of canopy dominant trees, jarrah and marri. These data suggested low recruitment success in infested forest. In contrast, densities of mature trees were unchanged within infested forest, possibly because of competitive release (i.e., fewer tree saplings, grasstrees and shrubs). I used novel DNA metabarcoding to examine how fungi are affected by P. cinnamomi. I found no change in richness and abundances of ectomycorrhizal fungi, arbuscular mycorrhizal, and saprotrophs, but minor shifts in assemblages of the latter two. Finally, I monitored quenda movements with GPS trackers. Fewer quendas were trapped within infested forest, suggesting preferential avoidance, but some quendas still moved through and nested within infestations.
Phytophthora cinnamomi has had cascading effects on the jarrah forest ecosystem by altering quenda habitat, but had minor impacts to fungi. Phytophthora cinnamomi can remain in soil for decades or longer. Planting shrubby, mycorrhizal native plants that are P. cinnamomi resistant may help to mitigate these impacts.
Details
- Title
- Cascading impacts of the plant pathogen Phytophthora cinnamomi to mycophagous quenda (Isoodon fusciventer) and native fungi
- Authors/Creators
- Thomas M Mansfield
- Contributors
- Rachel Standish (Supervisor) - Murdoch University, School of Environmental and Conservation SciencesTrish Fleming (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityShane Tobe (Supervisor) - Murdoch University, Centre for Biosecurity and One HealthGiles Hardy (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and Sustainability
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005674270107891
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Resource Type
- Doctoral Thesis
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