Ectomycorrhizal abundance and community structure from scrub pine hosts grown in contrasting soils

Variation in soil properties influences spatial patterns in ectomycorrhizal (ECM) fungal colonization and diversity. Although differential responses by ECM fungal communities to variable soil properties have been widely studied, fewer studies have examined ECM fungal communities from hosts growing in mafic soils. To better understand how ECM fungal communities are influenced by these soils, a field study was conducted to examine whether ECM abundance and community structure vary on host trees growing in mafic and non-mafic soils. To address these questions, soil cores were extracted from beneath Pinus virginiana trees from stands associated with mafic and non-mafic soils in a forest preserve in the Blue Ridge Mountains of Virginia. P. virginiana was used as the host tree because it commonly grows in both soil types and is relatively even-aged across preserve stands. Across soil sources, ECM abundance, measured as mean colonized root tips, was 72% higher on roots from host trees growing in mafic compared to non-mafic soils, but was not significantly higher. Mean richness and diversity per host tree were both higher on hosts from mafic compared to non-mafic soils, and mean richness was significantly higher on mafic hosts. These results suggest that increased host receptivity under mafic soil conditions affects ECM abundance and community properties, and that richer ECM fungal communities may occur on hosts growing in these soils.