Spatial partitioning of soil fungi along an urban to rural gradient

Background/Question/Methods

Soil fungi play a critical role in regulating ecosystem carbon fluxes, and changes in soil fungal community composition may significantly alter ecosystem processes. Urbanization may alter fungal community composition through effects on soil, such as soil chemistry, yet little is known about the environmental drivers that govern soil fungal community diversity. In this study, we use DNA cloning of fungal DNA to classify communities of soil fungi of the subkingdom Dikarya along an urban (Brooklyn, NY, USA) to rural (Litchfield County, CT, USA) gradient in the Greater New York City Metropolitan Area.

Results/Conclusions

Fungal community composition varied markedly among the seven sites sampled along the gradient. Six of the seven sites had a unique dominant genus, and the majority of the OTUs sequenced from each site were unique to that site. Canonical correspondence analysis and linear regressions indicated that shifts in fungal community composition were most closely associated with distance from an urban center and soil N concentration. Distance accounted for 20% of the variation in fungal community composition among sites. However, only about half of the variation in composition among sites was explained by the drivers investigated in this study, suggesting other biotic and abiotic factors may also play key roles in regulating fungal community composition. As urban populations grow and cities expand into more rural areas, a detailed understanding of the changes in soil microbial communities and the environmental variables that govern them will help indicate changing patterns and process in new urban ecosystems.