Phosphorus addition predominantly influences the soil fungal community and functional guilds in a subtropical mountain forest

Introduction: Fungal communities are key players in the soil biogeochemical processes of forest ecosystems. Although it has been illustrated that soil fungi are susceptible to environmental changes, little is known about the interactive effects of nitrogen (N) and phosphorus (P) enrichment on the soil fungal functional guild. Materials and Methods: Here, a 5-year N and P addition manipulation experiment was conducted in two growing stages (i.e., tree ages <40 and >80 years) of a subtropical forest, in which soil fungal diversity and functional guilds were investigated using a multiple-time sampling strategy. Results: Fungal species richness and Shannon indices were significantly different across sampling times. Fungal community composition was significantly affected by both N and P addition but not by forest age. Old forest had a higher fungal network complexity than young forest, and fertilisation decreased soil fungal network complexity and generated looser and more random networks in comparison with the control. The community composition of symbiotrophic and saprotrophic fungi was significantly impacted by N and P addition and correlated with soil available P and total P contents and soil C:P and N:P. Conclusions: Our findings highlight that soil P availability has a strong effect on soil fungal communities and their functional guild composition in the subtropical forest.