Modifications of Community Structure in Ectomycorrhizal Arctic Fungi as a Consequence of Global Warming

Arctic regions are experiencing the greatest changes of climate warming on the planet, and marked variations have already been observed in terrestrial arctic ecosystems. While most studies have focused on the effects of warming on arctic vegetation and nutrient cycling, little is known about how belowground communities, such as root-associated fungi, respond to warming. Similarly, there is also a gap in knowledge on how edible ectomycorrhizal fungal species will respond to climate changes. Here, we investigate how long-term summer warming affects ectomycorrhizal (ECM) fungal communities. We used Ion Torrent sequencing of the rDNA internal transcribed spacer 2 (ITS2) region to compare ECM fungal communities in plots with and without experimental warming over 18 years in both dry and moist tussock tundra in Alaska, USA. Warming had profound effects on community composition, abundance and, to a lesser extent, on richness of taxonomic and functional groups of ECM fungi. In addition, our data show that the direction and extent of response to warming tend to be species-specific and the reported compositional shifts in the community might affect nutrient cycling and soil organic C storage. We recommend that future studies on fungal communities and their roles in nutrient cycling take into account species-level responses.