Above and Below Ground Fungal Diversity in a Hemlock-dominated Forest Plot in Southern Ontario and the Phylogenetic Placement of a New Ascomycota Subphylum

The objective of this thesis was to assess the diversity and community structure of fungi in a forest plot in Ontario using a variety of field sampling and analytical methods. Three broad questions were addressed: 1) How do different measures affect the resulting view of fungal diversity? 2) Do fruiting bodies and soil rDNA sampling detect the same phylogenetic and ecological groups of Agaricomycotina? 3) Will additional rDNA sampling resolve the phylogenetic position of unclassified fungal sequences recovered from environmental sampling? Generally, richness, abundance, and phylogenetic diversity (PD) correspond and identify the same dominant fungal groups in the study site, although in different proportions. Clades with longer branch lengths tend to comprise a larger proportion of diversity when assessed using PD. Three phylogenetic-based comparisons were found to be variable in their ability to detect significant differences. Generally, the Unifrac significance measure (Lozupone et al., 2006) is the most conservative, followed by the P-test (Martin, 2002), and Libshuff library comparison (Singleton et al., 2001) with our dataset. Fruiting body collections and rDNA sampling recover largely different assemblages of fungi at the species level; however, both methods identify the same taxonomic groups at the genus-order level as well as ectomycorrhizal fungi as the dominant functional type of Agaricomycotina. This work also shows that the Soil Clone Group I (SCGI) clade is widespread in soils of diverse origins and represents a novel subphylum of Ascomycota.Ph