Impact of local forest composition on soil fungal communities in a mixed boreal forest

Abstract

While fungi are key drivers of the carbon cycle and obligate symbionts of trees, the link between plant-fungal interactions and landscape vegetation changes has been largely overlooked. Our aim was to test whether a local difference in dominant tree species would shape the composition of soil fungi communities. Fungal communities were described using next-generation DNA sequencing. Composite soil samples were collected in four paired sites (represented by one pure aspen stand and one pure spruce stand) and soil nutriments were measured. Of the more than 1119 OTUs, 31.6% were Ascomycota while 27.8% were Basidiomycota, 15% were ectomycorrhizal fungi whereas 19.7% were saprotrophic. Communities displayed high species turnover among forest types rather than differences in species richness. Among tested predictors, the dominant tree species explained around 11% of fungal community variation. pH and soil nutrients were also strong predictors of fungal communities. Our study revealed strong correlations between dominant tree species and fungal communities at a local scale and raised questions regarding the impact of fungal communities on forest soil nutrient dynamics.