Temporal dynamics in the taxonomic and functional profile of the Sphagnum-associated fungi (mycobiomes) in a Sphagnum farming field site in Northwestern Germany

Abstract

The drainage of peatlands for their agricultural use leads to huge emissions of greenhouse gases. One sustainable alternative is the cultivation of peat mosses after rewetting (‘Sphagnum farming’). Environmental parameters of such artificial systems may differ from those of natural Sphagnum ecosystems which host a rich fungal community. We studied the fungal community at a 4 ha Sphagnum farming field site in Northwestern Germany and compared it with that of natural Sphagnum ecosystems. Additionally, we asked if any fungi occur with potentially negative consequences for the commercial production and/or use of Sphagnum biomass. Samples were collected every three months within one year. High-throughput sequencing of the fungal ITS2 barcode was used to obtain a comprehensive community profile of the fungi. The dominant taxa in the fungal community of the Sphagnum farming field site were all commonly reported from natural Sphagnum ecosystems. While the taxonomic composition showed clear differences between seasons, a stable functional community profile was identified across seasons. Additionally, nutrient supply seems to affect composition of fungal community. Despite a rather high abundance of bryophyte parasites, and the occurrence of both Sphagnum-species-specific and general plant pathogens, their impact on the productivity and usage of Sphagnum biomass as raw material for growing media was considered to be low.

Does Shift in Vegetation Abundance After Nitrogen and Phosphorus Additions Play a Key Role in Regulating Fungal Community Structure in a Northern Peatland?

“…Clavaria sphagnicola , Galerina tibiicystis , G. sphagnicola , and G. paludosa ( Kostka et al, 2016 ; Borg Dahl et al, 2020 ) were recovered in this study and there were far fewer sequences in samples from the long-term experiment (1,289) relative to the short-term one (10,550). The lack of relationship between Sphagnum mosses and those fungi inhabiting their tissues and surface may be owing to the contrasting responses of different species.…”

“…After the loss of the “natural N filter” function of Sphagnum mosses when cumulative N deposition exceeds their immobilizing capacity, vascular plants may take advantage of increased available N in the soil ( Lamers et al, 2000 ; Chiwa et al, 2016 ; Wieder et al, 2020 ). The expansion of vascular plants to the detriment of Sphagnum may favor fungal functional guilds associated with shrubs, trees, and graminoids, especially mycorrhizal fungi, but is likely detrimental to fungal guilds associated with Sphagnum via endophytic or biotrophic relationships ( Kostka et al, 2016 ; Noordeloos et al, 2017 ; Borg Dahl et al, 2020 ). Besides, plant competition between PFT for nutrients will likely reshape the community of ericoid mycorrhizal (ErMF), arbuscular mycorrhizal (AMF), and ectomycorrhizal fungi (EcMF), which in turn regulates plant–plant interactions and ecosystem processes ( Smith and Read, 2008 ; Tedersoo et al, 2020 ).…”

Plant species composition and vegetation structure ofSphagnumcultivation sites

“…Regardless of the intention to grow Sphagnum, the created sites could also provide substitute habitat for rare and threatened species as an ancillary benefit. This has already been determined for spiders (Muster et al, 2015(Muster et al, , 2020, birds, amphibians, dragonflies, butterflies (Zoch & Reich, 2022) and fungi (Dahl et al, 2020). The suitability of such sites as substitute habitat for bog-typical and threatened plant species, including bryophytes, remains to be determined.…”

Table_1.docx

“…After the loss of the "natural N filter" function of Sphagnum mosses when cumulative N deposition exceeds their immobilizing capacity, vascular plants may take advantage of increased available N in the soil (Lamers et al, 2000;Chiwa et al, 2016;Wieder et al, 2020). The expansion of vascular plants to the detriment of Sphagnum may favor fungal functional guilds associated with shrubs, trees, and graminoids, especially mycorrhizal fungi, but is likely detrimental to fungal guilds associated with Sphagnum via endophytic or biotrophic relationships (Kostka et al, 2016;Noordeloos et al, 2017;Borg Dahl et al, 2020). Besides, plant competition between PFT for nutrients will likely reshape the community of ericoid mycorrhizal (ErMF), arbuscular mycorrhizal (AMF), and ectomycorrhizal fungi (EcMF), which in turn regulates plant-plant interactions and ecosystem processes (Smith and Read, 2008;Tedersoo et al, 2020).…”