How soil fungal communities respond to invasive plant species treatments in soil from Banksia woodland, southwestern Australia.

Aaron Justin Brace; Katinka Ruthrof; Joe Fontaine; Ben Miller; Anna Hopkins

Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

How soil fungal communities respond to invasive plant species treatments in soil from Banksia woodland, southwestern Australia.

Aaron Justin Brace , Katinka Ruthrof, Joe Fontaine, Ben Miller , Anna Hopkins

Abstract

Abstract Context: Invasive plants are one of the most significant threats to woodlands globally. Methods of invasive plant control include manual removal and herbicide application. While the impacts of control methods on invasive and off-target native plant species are often explored, the impacts on below-ground organisms, such as fungi, are less well understood. Aims: We conducted a glasshouse trial to investigate the responses of soil fungal communities to herbicides and manual removal, which are used to control common invasive plant species in Banksia woodland in southwestern Australia. Methods: Three herbicides; broad spectrum (glyphosate and pelargonic acid) and grass-specific (fluazifop-p-butyl) were separately applied at the recommended woodland rate to pots either containing Ehrharta calycina, a key invasive grass species, or Eucalyptus todtiana, a native woodland tree. After six weeks, samples of treated soils were then subjected to high throughput sequencing to determine fungal community diversity, richness, relative abundance, composition, and putative ecosystem function. Key Results: Pelargonic acid induced the widest changes including decreased fungal richness and Shannon diversity, but all affected community composition. Within functional groups, fluazifop-b-butyl led to a large decrease of symbiotrophs in the mycorrhizal species. Conclusions: We show that invasive species management, in the manner applied, can lead to immediate changes in fungal community composition. Implications: Observed patterns require further exploration, specifically, repeat testing under different environmental conditions, to better determine the impact and mode of action of herbicides on below ground organisms. The functional changes in the soil fungal community could further disturb the soil fungal community and complicate subsequent management considerations.

BT24083 Accepted 29 April 2025