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Data from: Ectomycorrhizal fungi are more sensitive to high soil nitrogen levels in forests exposed to nitrogen deposition

Jörgensen, Karolina1; Clemmensen, Karina E.1; Wallander, Håkan2; Lindahl, Björn D.1

Published Jan 05, 2024 on Dryad. https://doi.org/10.5061/dryad.5hqbzkhcp

Data files

Jan 05, 2024 version files 105.11 KB

Abstract

Ectomycorrhizal fungi are essential for nitrogen cycling in many temperate forests and responsive to anthropogenic nitrogen addition, which generally, decreases host carbon allocation to the fungi. In the boreal region, however, ectomycorrhizal fungal biomass has been found to correlate positively with soil nitrogen availability. Still, responses to anthropogenic input, for instance through atmospheric deposition, are commonly negative.

To elucidate whether variation in nitrogen supply affects ectomycorrhizal fungi differently depending on geographical context, we investigated ectomycorrhizal fungal communities along two fertility gradients across nemo-boreal forests with similar ranges in soil N/C ratios and inorganic nitrogen availability but located in regions with contrasting rates of nitrogen deposition.

Ectomycorrhizal biomass and community composition remained relatively stable across the nitrogen-gradient with low atmospheric nitrogen deposition, but biomass decreased, and the community changed more drastically, with increasing nitrogen availability in the gradient subjected to higher rates of nitrogen deposition. Moreover, potential activities of enzymes involved in ectomycorrhizal mobilisation of organic nitrogen decreased as N/C ratios increased.

In forests with low external input, we propose that stabilising feedbacks in tree-fungal interactions maintain ectomycorrhizal fungal biomass and communities even in highly fertile soils. In contrast, anthropogenic nitrogen input seems to impair ectomycorrhizal functions.