Contrasting Patterns and Drivers of Soil Fungal Communities between Two Ecosystems Divided by the Treeline

The treeline is a sensitive region of the terrestrial ecosystem responding to climate change. However, studies on the composition and formation mechanisms of soil fungal communities across the treeline are still lacking. In this study, we investigated the patterns of soil fungal community composition and interactions among functional guilds above and below the treeline using Illumina high-throughput sequencing and ecological network analysis. The results showed that there were significant differences in the soil environment and soil fungal community composition between the two ecosystems above and below the treeline. At the local scale of this study, geographic distance and environmental factors affected the composition of the soil fungal community. Soil temperature was an important environmental predictor of soil fungal community composition. Species in soil fungal communities in the subalpine meadow were more closely related to each other compared to those in the montane forest. Furthermore, the soil fungal community in montane forest was more stable. Our findings contribute to a better understanding of how mountain ecological functions respond to global climate change.

Fungal Community Composition and Diversity Vary With Soil Horizons in a Subtropical Forest

Soil fungal communities, which drive many ecosystem processes, vary across soil horizons. However, how fungal communities are influenced by soil horizon layers remains largely unstudied. In this study, soil samples were collected from the organic horizon (O horizon) and mineral matter horizon (M horizon) in two sites of Dabie Mountain, China, and the effects of the two horizons on the soil fungal community composition were assessed based on Illumina MiSeq sequencing. Our results showed that soil fungal community composition varied with soil horizons, and soil fungal species richness and diversity in the O horizon were significantly higher than that in the M horizon. Total organic carbon (TOC), total organic nitrogen (TON), alkali-hydrolyzable nitrogen (AHN), available potassium (AK), and available phosphorus (AP) significantly influenced fungal community composition, abundance, and diversity across the two horizons (P < 0.05). Furthermore, precipitation was found to have a significant effect on fungal community composition. Our results demonstrate changes in fungal communities across soil horizons and highlight the importance of soil organic matter on fungal communities and diversity.

Soil fungal community composition and functional similarity shift across distinct climatic conditions

ABSTRACT A large part of ecosystem function in woodland systems depends on soil fungal communities. However, global climate change has the potential to fundamentally alter these communities as fungal species are filtered with changing environmental conditions. In this study, we examined the potential effects of climate on host-associated (i.e. tree-associated) soil fungal communities at climatically distinct sites in the Tehachapi Mountains in California, where more arid conditions represent likely regional climate futures. We found that soil fungal community composition changes strongly across sites, with species richness and diversity being highest at the most arid site. However, host association may buffer the effects of climate on community composition, as host-associated fungal communities are more similar to each other across climatically distinct sites than the whole fungal community. Lastly, an examination of functional traits for ectomycorrhizal fungi, a well-studied guild of fungal mutualist species, showed that stress-tolerant traits were more abundant at arid sites than mesic sites, providing a mechanistic understanding of these community patterns. Taken together, our results indicate that fungal community composition will likely shift with future climate change but that host association may buffer these effects, with shifts in functional traits having implications for future ecosystem function.