Date of Award
2024
Document Type
Thesis
Publisher
Edith Cowan University
Degree Name
Doctor of Philosophy
School
School of Science
First Supervisor
Anna Hopkins
Second Supervisor
Katinka Ruthrof
Third Supervisor
Joe Fontaine
Fourth Supervisor
Ben Miller
Abstract
This research aims to fill the knowledge gap in soil fungi in the Banksia woodland and emphasizes considering holistic ecosystem dynamics in invasive species management strategies. This is accomplished by surveying soil fungi under different fire regime across the Swan Coastal Plain, and within both in and ex situ herbicide application trials. This is the first such study to investigate the fungal component of the Banksia woodland so thoroughly. Chapter 2 quantified and analysed changes in soil fungal community composition and functional groups over a 50-year fire chronosequence in fire-prone Banksia woodland in southwestern Australia. Effects were variable, but fungal abundance increased with increasing time since fire, especially among symbiotrophic fungi. We found that the Banksia woodland fungal community responses varied across the post-fire chronosequence for different soil types and depths, especially when considering functional groups. Chapter 3 quantified soil fungal dynamics over the first 12 months after fire in Banksia woodlands in southwest Australia. Over the post-fire sampling period, richness and diversity declined and soil fungal community composition changed significantly throughout the sampling period, with family level taxa and functional groupings experiencing the most change. Through the sampling period, an increase in saprotrophic and endophytic fungi was observed, along with a decrease in all pathogenic fungi. Chapter 4, soil samples were collected from areas with prescribed burn and/or herbicide application in two urban woodlands. the soil fungal community in the two sites responded similarly and was broadly resistant to the management applications. However, herbicide application was associated with declines in relative abundances of some phyla and families, as well as key functional groups. Fire seemed to offset the negative effects of herbicide application, indicating complex interactions with the soil fungal community. Herbicide application in combination with fire is critical for grassy weed management and promoting native plant species. Chapter 5 investigated how soil fungal communities in glasshouse conditions responded to herbicides used for controlling invasive species in Banksia woodlands in southwestern Australia. Pelargonic acid was observed to induce the most decreases in fungal richness and Shannon diversity. Within functional groups, fluazifop-b-butyl increased the relative abundance of pathotrophs. We show that some herbicides, in the manner applied, can lead to immediate changes in the fungal community. Finally, chapter 6 synthesises all the previous chapters and deals with the global and management implications moving forward. Overall, this study not only provided an identification of over 3.5 million sequences across 20,838 unique fungal ASVs, but also explores gaps in the knowledge, with a large amount of taxonomic and functional information still missing more work is required to sequence and identify possibly characteristic fungi. Throughout the 4 projects the effects of wildfires, prescribed burns, and herbicide on the soil fungal community of the Banksia woodland have been demonstrated. This is the largest study based in this system to date, a system unique in its domination by a non-mycorrhizal tree.
DOI
10.25958/zcr2-v485
Access Note
Access to this thesis is embargoed until 10th January 2030
Recommended Citation
Brace, A. J. (2024). Shifting soil fungal communities in response to fire and weed management in urban Banksia woodlands. Edith Cowan University. https://doi.org/10.25958/zcr2-v485