ARCTIC MYCORRHIZAL INTERACTIONS UNDER CLIMATE CHANGE

Abstract

The Arctic is experiencing climate change at an extreme rate, affecting both the rates of plant growth and nutrient cycling. Due to the changes in temperature, but also in nutrient cycling, with increased nutrient mineralization and decreasing P:N ratio (phosphorus, P and nitrogen, N), the arbuscular mycorrhizal fungi (AM) that are prevalent in warmer soils have shown the potential to increase in the otherwise unfavorable Arctic environment. Additionally, graminoids that are commonly associated with AM, are increasing in abundance in response to climate change. Despite this, the association between graminoids and AM in the Arctic has rarely been the focus of research, and how it is affected by increasing temperatures is not well understood. This study used an altitudinal gradient in subarctic Scandinavia as a proxy for climate change to show a potential positive relationship between climate change and AM association in the Arctic graminoid Poa alpina. A likely positive relationship was found between AM association and temperature, and a potential, although uncertain, negative relationship between soil P and AM association. While no significant relationship was found between tissue P and either temperature, soil P or AM association, a negative relationship was found between tissue N and AM association. The likely relationship found between temperature and AM association is similar to that found in the forb–AM association and contributes to the scare knowledge about the graminoid–AM interaction, while the tissue nutrient analyses indicated that AM association could be most beneficial for the most nutrient limited plants. These trends indicate that their AM association has the potential to improve the fitness of Arctic graminoids in a warmer climate, and if future research confirms these trends, it would further our understanding of why certain Arctic plants benefit from climate change.