Dataset for Moriana-Armendariz et al. 2021- Increased snow and cold season temperatures alter High Arctic parasitic fungi - host plant interactions.

In the Arctic, fungal mycelial growth takes place mainly during the cold-season and beginning of growing season. Climate change induced increases of cold-season temperatures may, hence, benefit fungal growth and increase their abundance. This is of special importance for parasitic fungi, which may significantly shape Arctic vegetation composition. Here, we studied two contrasting plant parasitic fungi’s occurrences (biotrophic Exobasidium hypogenum on vascular plant Cassiope tetragona, and necrotrophic Pythium polare on moss Sanionia uncinata) in response to increased snow depth, a method primarily used to increase cold-season temperatures, after 7-13 years of snow manipulation in Adventdalen, Svalbard. We show that enhanced snow depth increased occurrences of both fungi tested here, and indicate that increased fungal infections of host plants were at least partly responsible for decreases of host occurrences. While bryophyte growth in general may be influenced by increased soil moisture and reduced competition from vascular plants, Pythium is likely enhanced by the combination of milder winter temperatures and moister environment provided by the snow. The relationships between host plants and fungal infection indicate ongoing processes involved in the dynamics of compositional adjustment to changing climate.

R, 3.6.1