Fungal Succession and Diversity in Ectomycorrhizal Associations: A Case Study Approach

This paper examines fungal succession among ectomycorrhiza-forming fungi by reviewing several studies. The first group of studies confirmed that common nursery fungi were replaced by other species over time. The second series of experiments showed that the root system underwent a succession of fungi as the stand aged. Fungi were apparently associated with certain parts of the root system: the youngest roots with early-succession species and the older part of the root system with later-stage species. The next series of studies showed that disturbing tree roots of existing plants changed the fungal species that formed mycorrhizas on roots of newly planted seedlings adjacent to the existing plants. Other studies showed that the removal of the surface layers of the forest floor increased both fungal species richness and abundance of fruiting bodies. However, the increase in fruiting body production was observed to occur primarily in early succession fungal species. Finally, it was shown that the youngest stands had few very abundant fungal species, with other species present in low to very low quantities. Over time, the fungal population changed with more species present, but the roots were still dominated by relatively few species.