Arbuscular Mycorrhizal Fungal Communities In Maize Fields Are Diverse, Strongly Dominated, and Likely Shaped by Soil Textural Characteristics.

Arbuscular mycorrhizal fungi (AMF) are of interest to agroecology due to the numerous potential benefits their presence can provide.  But, while mycorrhizal host plants are non-specific in association with AM fungi, the functional outcome of the interaction varies depending on the identities of the partners.  So, it is important to understand the composition of the AMF community in agroecosystems, and to identify the features of these environments that the fungal community structure may take shape in response to.  We explored the AMF community in a selection of maize fields across a landscape in eastern New York State and characterized their diversity, dominance, and species abundance distribution.  Species abundances were distributed lognormally, suggesting that several factors influence community structure.  We observed strong dominance across the landscape and in multiple fields of one taxon, while other taxa were frequent but never dominant.  This abundance distribution, diversity, and pattern of strong dominance, are consistent with observations for AMF communities in other, non-agricultural ecosystems.  We used indirect gradient analysis, using NMDS ordination of both taxon-based (Bray-Curtis) and phylogeny-based (UniFrac) dissimilarity measures, to identify edaphic factors shaping the AMF community.  The two approaches revealed different, but complementary, indications that soil textural components, rather than phosphorus or pH, are associated with compositional differences in the AMF community structure.