Effects of nitrogen fertilization on fungal community structure in a temperate hardwood forest: Implicit links between structure, function and resilience.

摘要

This study documents soil fungal communities at the Harvard Forest Chronic Nitrogen Addition experiment, which was established in 1989 to test the effects of long-term nitrogen fertilization on ecosystem processes. Researchers at this site have observed an accumulation of soil carbon in the nitrogen fertilized plots and a decrease in fungal biomass, ligninolytic enzyme activity, and rates of litter decay. We hypothesized that decreased decomposition rates in nitrogen-fertilized plots were due to changes in the structure of the fungal community, especially Basidiomycetes, the primary decomposers of lignin in this ecosystem. We performed a marker gene study of fungal communities in the organic soil horizon using 454 high-throughput sequencing of three separate loci. The dominant OTU increased significantly in relative abundance in the highest N treatment. Additionally, Basidiomycete community composition was altered by N additions. These results suggest that changes in fungal community structure may contribute to decreased decomposition rates.