Comprehensive sampling of an isolated dune system demonstrates clear patterns in soil fungal communities across a successional gradient

Abstract

Coastal sand dunes are extremely dynamic ecosystems, characterized by stark ecological succession gradients. Dune stabilization is mainly attributed to plant growth, but the establishment and survival of dune-inhabiting vegetation is closely linked to soil microorganisms and to the ecological functions they fulfill. Fungi are particularly important in this context, as some interact intimately with plant roots, while others are critical to soil structure and nutrient availability. Our study aimed to describe wholly fungal diversity and community composition in a secluded coastal dune ecosystem at eight different stages of succession. We comprehensively sampled a relic foredune plain, which is part of an archipelago in the Gulf of Saint Lawrence (Québec, Canada), by collecting soils from 80 sites and measuring soil characteristics. Soil fungal communities were characterized by pyrosequencing, followed by taxonomic classification and assignment of putative roles. Even though we did not observe clear patterns in diversity, we were able to detect distinct taxonomic and community composition signatures across succession stages, which seemed to translate into variations in fungal life strategies. Our results show that a taxonomically and functionally diverse fungal community exists at each dune succession stage, even in the barren foredunes.

High richness of ectomycorrhizal fungi and low host specificity in a coastal sand dune ecosystem revealed by network analysis

“…Details about the study system and its soil fungal communities are described in more detail in Roy‐Bolduc et al. (2015). …”

“…The inter-ridge swales harbor a diverse array of vegetation, including several Ericaceae, Sphagnum, and Carex species. Details about the study system and its soil fungal communities are described in more detail in Roy-Bolduc et al (2015).…”

Soil Microbial Networks Shift Across a High-Elevation Successional Gradient

“…While the vast majority of research on community patterns along successional gradients has focused on macroorganisms, shifts in microbial communities are beginning to be addressed. Recent work suggests that the composition of microbes changes considerably and predictably during primary succession (Nemergut et al, 2007;Tarlera et al, 2008;Roy-Bolduc et al, 2015;Poosakkannu et al, 2017), with certain groups like Actinobacteria and N fixers prevalent in early successional stages, and other groups such as Acidobacteria and mycorrhizal taxa dominating later stages (Rime et al, 2015;Poosakkannu et al, 2017;Yarwood and Högberg, 2017). Much work also suggests that the taxonomic diversity (Nemergut et al, 2007;Tarlera et al, 2008;Brown and Jumpponen, 2014;Rime et al, 2015;Poosakkannu et al, 2017) and functional diversity (Tscherko et al, 2003) of soil bacterial and fungal communities generally increase during succession.…”

Maintenance of host specialisation gradients in ectomycorrhizal symbionts

“…Plants may benefit from specialists by hedging their bets by associating with both generalists and specialists. This bet‐hedging might explain why tree hosts associate with generalists yet also support communities comprising specialist ECM fungi (Horton et al ., 2005; Roy‐Bolduc et al ., 2015). Similarly, generalist fungi that maintain this lifestyle are protected against loss of a specific host tree species or genera for the same reasons.…”