Variable effects of ectomycorrhizal fungi on litter decomposition in temperate pine forests

In this study, we tested the hypothesis that ectomycorrhizal (ECM) fungi suppress the decomposition of N-poor, recalcitrant litter more in forests with low N-availability by exacerbating saprotrophic N limitation. We conducted an in-situ ECM fungi and root reduction experiment (via soil trenching) in nine pine forests across three US states, which varied in soil and litter N content, climate, and pine host (Pinus muricata in California, P. elliottii in Florida, and P. resinosa in Minnesota). In each site, we decomposed needle litter from (1) a pine species native to that site and (2) a common litter, P. strobus, for one year. We then characterized the fungal communities colonizing litter using high-throughput sequencing of the ITS2 region.