Variation in forest soil fungal diversity along a latitudinal gradient

In forest ecosystems, plant communities shape soil fungal communities through the provisioning of carbon. Although the variation in forest composition with latitude is well established, little is known about how soil fungal communities vary with latitude. We collected soil samples from 17 forests, along a latitudinal transect in western China. Forest types covered included boreal, temperate, subtropical and tropical forests. We used 454 pyrosequencing techniques to analyze the soil communities. These data were correlated with abiotic and biotic variables to determine which factors most strongly influenced fungal community composition. Our results indicated that temperature, latitude, and plant diversity most strongly influence soil fungal community composition. Fungal diversity patterns were unimodal, with temperate forests (mid latitude) exhibiting the greatest diversity. Furthermore, these diversity patterns indicate that fungal diversity was highest in the forest systems with the lowest tree diversity (temperate forests). Different forest systems were dominated by different fungal subgroups, ectomycorrhizal fungi dominated in boreal and temperate forests; endomycorrhizal fungi dominated in the tropical rainforests, and non-mycorrhizal fungi were best represented in subtropical forests. Our results suggest that soil fungal communities are strongly dependent on vegetation type, with fungal diversity displaying an inverse relationship to plant diversity.