Disturbance History and Environmental Characteristics Shape the Ectomycorrhizal Fungal Community of Two Varieties of Pinus clausa

The soil biota is diverse, yet the ecological and evolutionary processes that regulate species diversity and abundance of soil microorganisms across space and time remains elusive. In forest ecosystems, periodic disturbances which operate at different time scales represent one possible avenue by which diversity in the soil biota may be maintained due to their effect on genetic and phenotypic characteristics of the host and associated environment. To investigate the degree to which host variety and environmental characteristics shape the belowground ectomycorrhizal (ECM) fungal community, we sampled ten populations of a single pine species that has diverged into two genetically distinct varieties as a result of disturbance history (Pinus clausa var. immuginata and var. clausa) and used multivariate analysis to relate the community matrices of ECM fungi to host and environmental characteristics. Host variety was an important determinant of ECM fungal community structure and diversity at both the species level and when fungi were grouped into categories based on their substrate exploration and nutrient acquisition strategies independent of environmental characteristics. Overall, our results suggest that periodic disturbances which shape the host populations are also important for structuring the ECM fungal community independent of environmental effects.