Long-Term Experimental Nitrogen Deposition Alters the Composition of the Active Fungal Community in the Forest Floor

Global increases in the rate of atmospheric N deposition have the potential to alter the composition and function of soil microbial communities. Here, we tested the hypothesis that experimental N deposition has altered the composition of active communities of Dikarya fungi. Such a change may underlie previously observed reductions in decomposition and increases in soil organic matter in a long-term field experiment. The actively metabolizing forest floor fungal community was characterized from cDNA clone libraries constructed from 28S fungal rRNA extracted from the forest floor of two northern hardwood stands in the lower peninsula of Michigan. We demonstrate that long-term experimental N deposition altered the composition of the active communities of Dikarya fungi in the forest floor in each of these forest stands. Because forest floor fungi are important decomposers, the alteration of forest floor fungal communities by increasing N deposition may have implications for the cycling and storage of C in forest ecosystems.