Abrupt changes in the composition and function of fungal communities along an environmental gradient in the high Arctic

Abstract

Fungi play a key role in soil-plant interactions, nutrient cycling and carbon flow and are essential for the functioning of arctic terrestrial ecosystems. Some studies have shown that the composition of fungal communities is highly sensitive to variations in environmental conditions, but little is known about how the conditions control the role of fungal communities (i.e., their ecosystem function). We used DNA metabarcoding to compare taxonomic and functional composition of fungal communities along a gradient of environmental severity in Northeast Greenland. We analysed soil samples from fell fields, heaths and snowbeds, three habitats with very contrasting abiotic conditions. We also assessed within-habitat differences by comparing three widespread microhabitats (patches with high cover of Dryas, Salix, or bare soil). The data suggest that, along the sampled mesotopographic gradient, the greatest differences in both fungal richness and community composition are observed amongst habitats, while the effect of microhabitat is weaker, although still significant. Furthermore, we found that richness and community composition of fungi are shaped primarily by abiotic factors and to a lesser, though still significant extent, by floristic composition. Along this mesotopographic gradient, environmental severity is strongly correlated with richness in all fungal functional groups: positively in saprotrophic, pathogenic and lichenised fungi, and negatively in ectomycorrhizal and root endophytic fungi. Our results suggest complex interactions amongst functional groups, possibly due to nutrient limitation or competitive exclusion, with potential implications on soil carbon stocks. These findings are important in the light of the environmental changes predicted for the Arctic.

Relationships between plant diversity and soil microbial diversity vary across taxonomic groups and spatial scales

“…4a). Saprophytic microbes have a wide range of functional abilities, and most soils contain most functional guilds of saprophytes (H€ attenschwiler et al 2005, Grau et al 2017, Semchenko et al 2018). The positive relationship, thus, supports the idea of a functional relationship between plants and microbes at the global scale Jackson 2006, Chen et al 2019).…”

Mycorrhizal fungi affect orchid distribution and population dynamics

“…Fungal communities are well known to differ among habitats and to be patchily distributed (e.g. Grau et al ., ; Maghnia et al ., ; Chaudhary et al ., ), but OMFs have received little attention. Bunch et al .…”

“…Fungal communities are well known to differ among habitats and to be patchily distributed (e.g. Grau et al, 2017;Maghnia et al, 2017;Chaudhary et al, 2018), but OMFs have received little attention. Bunch et al (2013) found that Cypripedium acaule associated with different OMFs in locations with different soil chemistry.…”

Of mammals and bacteria in a rainforest: Temporal dynamics of soil bacteria in response to simulated N pulse from mammalian urine

“…The earlier-mentioned global prevalence of spatial heterogeneity in soil microbial communities has potential implications for the interactions, survival, and evolution of virtually all terrestrial organisms. Both symbiotic mutualists and pathogens, two functional groups that have the most direct effects on plant and animal survival and reproduction, generally show strong compositional differences among habitats at a landscape scale (Geml et al, 2016;Grau et al, 2017). Because many of these exhibit substantial differences in interacting with various plants and animals, these soil microbes can enable the co-existence of closely related species, either by niche divergence, as shown in Osborne et al, or by density-dependent interactions.…”