Renbetets effekt på mycelbiomassans utveckling i Arktis

Abstract

Today’s global warming is becoming strongly evident, bringing numerous consequences towards both nature and humanity, with the Arctic warming faster than other regions. Extramatrical mycelium (EMM), from mycorrhizal fungi, plays a key role in the soil organic carbon storage and sequestration in sub- and oroarctic ecosystems. Although much is still unknown regarding the development of these hyphal networks, they are strongly influenced by climatological factors and the pressure of herbivore grazing. This study aimed to more closely investigate how the production of EMM evolves over time within four northern sites spread out across Sweden and Finland: Långfjället (LAN), Sonfjället (SON), Ritsem meadow (RIG), and Kilpisjärvi (KLP). This was done through an experiment starting in 2020 where the fungal biomass of enclosed sample areas was compared to ambient ones divided by time of incubation. The mesh bags used were placed in the soil over time, ranging from one growing season up to two years and one growing season. The samples were then processed for ergosterol to be extracted and analyzed in order to retrieve the total biomass in kg C/ha. A consistent pattern found in the results was that incubation category D, which had spent the longest time in the ground, was associated with higher levels of biomass. Further, the results pointed to a higher production rate in areas without the influence of reindeer grazing - a pattern especially true for RIG. The lowest amount of biomass was found in KLP. This could be attributed to both a later enclosure of the area, as well as having the highest latitude out of all study sites and therefore being shaped by the cold climate. A general correlation between increasing latitude and decreasing biomass could be observed despite the fact that LAN was the only area not being statistically significant for the incubation time. In conclusion, this study demonstrates that incubation length, geographical location, and herbivore regulation are all tightly interconnected drivers of EMM accumulation in sub- and oroarctic ecosystems.