Response of soil fungal richness and composition to Lantana camara L. infestation in the Toowoomba region, South-East Queensland, Australia

Infestations by the weedy perennial plant Lantana camara L. (lantana) cause major disruptions to biodiversity; however, the effects of lantana on soil fungal communities are poorly understood, yet may interrupt important mutualisms in natural and semi-natural ecosystems. This research is aimed at understanding the impacts of lantana on the soil fungal community of five sites on contrasting soils in the Toowoomba region of south-east Queensland. Soil samples were collected from paired lantana infested and non-infested plots and the soil fungal community ascertained via analysis of terminal restriction fragments (TRFs) of isolated fungal DNA samples. Soils from these plots were also sampled for a range of chemical characteristics. Forty-eight identifiable fungal TRFs were recovered from the T-RFLP analysis. Mean fungal taxon richness showed no significant differences between lantana infested and non-infested plots across the range of sites examined. However, one site on nutrientpoor granitic soils had significantly higher (ANOVA, p<0.001) fungal taxon richness than other sites on other soils. While a number of fungal taxa were ubiquitous across all sites and lantana infested and non-infested plots, some taxa were exclusively found in either infested or non-infested plots at one site, suggesting some association between fungal composition and infestation. We conclude that there are no differences in the fungal taxon richness between lantana infested and non-infested plots, but a significant difference in mean fungal taxon richness between sites representing contrasting soil types. Further analysis of fungal composition may reveal more conclusive patterns regarding the possible effects of lantana invasion on soil fungal assemblages. Further research is required to confirm compositional differences with respect to lantana infestation and determine whether such effects are the direct effects of allelopathy or indirect effects of changes to soil properties.