We present one of the first analyses of ectomycorrhizal communities on native Nothofagus in New Zealand, and contrast these with fungal communities associated with invasive Pinus. As part of a study of timber harvesting effects belowground we sampled two Nothofagus-dominated forests for fungal diversity. Fungal species were identified using database T-RFLP (terminal-restriction fragment length polymorphism) and sequencing.
Results/Conclusions
Despite New Zealand being an isolated archipelago with relatively few native ectomycorrhizal trees, we found a high diversity of ectomycorrhizal fungi under Nothofagus. Ectomycorrhizal fungal species richness was only slightly lower than a range of reports from northern hemisphere Fagaceae forests (estimated 139 total species richness in NZ Nothofagus, compared to 143-195 species estimated in northern hemisphere Fagaceae forests), and was higher than would be expected based on plant host diversity. In part, fungal diversity was driven by a high number of Cortinariaceae species. Timber harvesting impacts on fungal communities were complex, and at least partially driven by increased soil moisture following tree removal. In contrast to native Nothofagus forest, invasive Pinus contorta trees are associated with a depauperate fungal community dominated by non-native fungi, particularly Amanita muscaria, Suillus luteus, and an unknown Cantharellales. This suggests that Pinus contorta is co-invading New Zealand with a consortium of fungi from its native range, and only forming sparse associations with native fungi. Differences in physiology between the fungal associates of Nothofagus and Pinus may explain marked differences in the abilities of Pinus and Nothofagus to establish into grasslands.
