Herbicide, not prescribed burning, drives larger shifts in soil fungal communities in a Mediterranean-type urban woodland

Invasive species management is increasingly important for conservation of native ecosystems, particularly for urban reserves, given their high value, visibility and disturbance. Often control methods for invasive weed species do not consider lesser-known facets of ecosystems, such as the soil fungal community. We collected soil samples from areas treated with prescribed burns, herbicide application, and combined prescribed burn and herbicide in two Mediterranean climate-type, urban woodlands in southwestern Australia, and subjected the extracted DNA to high throughput sequencing to describe the fungal communities present. We found that the soil fungal community in the two sites responded similarly and was broadly resistant to the management applications. However, herbicide application was associated with a reduction in relative abundances of some phyla and families, as well as key functional groups, compared to non-treated controls. Fire appeared 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 regeneration in this system. Our results highlight the need to further examine herbicide effects on soil fungi and further research is needed to quantify effect duration for all treatments. • Invasive species threaten biodiversity and are controlled in a variety of ways. • Many methods are macro-organism-focused and may affect non-target microbes. • A combination of herbicide and fire was undertaken in an urban Banksia Woodland. • Herbicides were associated with lower fungal richness and altered composition. • Prescribed burns offset the effect of herbicide application on the soil fungi.