Abiotic rather than biotic filtering shapes the arbuscular mycorrhizal fungal communities of European seminatural grasslands

Abstract

Although it is well known that arbuscular mycorrhizal fungi (AMF) play a key role in the functioning of natural ecosystems, the underlying drivers determining the composition of AMF communities remain unclear. In this study, we established 138 sampling plots at 46 grassland sites, consisting of 26 acidic grasslands and 20 calcareous grasslands spread across eight European countries, to assess the relative importance of abiotic and biotic filtering in driving AMF community composition and structure in both the grassland soils and in the roots of 13 grassland plant species. Soil AMF communities differed significantly between acidic and calcareous grasslands. In root AMF communities, most variance was attributable to soil variables while very little variation was explained by host plant identity. Root AMF communities in host plant species occurring in only one grassland type closely resembled the soil AMF communities of that grassland type and the root AMF communities of other host plant species occurring in the same grassland type. The observed AMF-host plants networks were not modular but nested. Our results indicate that abiotic conditions, rather than biotic filtering through host plant specificity, are the most important drivers in shaping AMF communities in European seminatural grasslands.

Contrasting effects of host identity, plant community, and local species pool on the composition and colonization levels of arbuscular mycorrhizal fungal community in a temperate grassland

“…Soil N availability has often been reported as a driving factor of AMF community composition (Egerton-Warburton et al, 2007;Fitzsimons et al, 2008;Antoninka et al, 2011;Camenzind et al, 2014), and the variation in soil moisture can similarly select AMF taxa more supportive to plants under drought conditions (Yang et al, 2017). The dominating impact of soil properties on the identity and abundance of AMFs has been widely reported in literature (Bouffaud et al, 2016;Dassen et al, 2017;Van Geel et al, 2018). However, it is surprising to find it at such a small spatial scale of metres.…”

“…The role of plant host identity in determining the set of colonizing AMFs and their quantity has been a frequent topic in current research (Eom et al, 2000;Lekberg & Waller, 2016;Van Geel et al, 2018). When examined with data collected at wider spatial scales, and often based on database records, plant identity has rarely played an important role (Lekberg & Waller, 2016;Van Geel et al, 2018; but see Davison et al, 2015), probably due to a larger variation in environmental conditions and to a nonrandom choice of hosts investigated in studies using database data. Our research, however, belongs to studies performed at a more local level, across one or a few ecosystem types (Eom et al, 2000;De Deyn et al, 2011).…”

“…Besides the mutual effects of the AMFs and their plant hosts, the occurrence and abundance of AMFs are known to be affected by multiple soil parameters, with soil pH playing a notable role (Fitzsimons et al ., ; Davison et al ., ; Bouffaud et al ., ; Oehl et al ., ; Van Geel et al ., ), particularly at smaller spatial scales (Rasmussen et al ., ), as well as the availability of N (Camenzind et al ., ; Fitzsimons et al ., ; Van Geel et al ., ) and P (Gosling et al ., ; Camenzind et al ., ).…”

Arbuscular mycorrhizal fungi in European grasslands under nutrient pollution

“…Mycorrhizal fungi are widely recognized as key below-ground symbionts that sustain primary production, biogeochemical cycling and biodiversity (Bardgett & van der Putten, 2014;Bender, Wagg, & Heijden, 2016;Brundrett & Tedersoo, 2018;van der Heijden, Martin, Selosse, & Sanders, 2015;Wagg, Jansa, Schmid, & Heijden, 2011). Consequently, much ecological research has focused on understanding patterns of mycorrhizal fungal diversity, indicating that mycorrhizal fungal communities show considerable variation that is related to environmental conditions (Jacquemyn et al, 2016;Leff et al, 2015;Partel et al, 2017;van der Linde et al, 2018;Van Geel, Jacquemyn et al, 2017). A matter of concern is the numerous observations that anthropogenic disturbances seem to exert a negative impact on mycorrhizal fungal communities, possibly undermining their role in maintaining pivotal ecosystem services (Cotton, 2018;Helgason, Daniell, Husband, Fitter, & Young, 1998;Partel et al, 2017;Vályi, Rillig, & Hempel, 2015;Verbruggen et al, 2018).…”

Cross‐scale integration of mycorrhizal function

“…Drivers of AM fungal community assembly in grasslands were also explored across 46 sites in six European countries (Van Geel et al ., , pp. 1262–1272), across different spatial scales in Åland archipelago of Finland (Rasmussen et al ., , pp.…”