Core arbuscular mycorrhizal fungi are predicted by their high abundance–occupancy relationship while host‐specific taxa are rare and geographically structured

Abstract

Habitat restoration may depend on the recovery of plant microbial symbionts such as arbuscular mycorrhizal (AM) fungi, but this requires a better understanding of the rules that govern their community assembly.We examined the interactions of soil and host-associated AM fungal communities between remnant and restored patches of subtropical montane forests.While AM fungal richness did not differ between habitat types, community membership did and was influenced by geography, habitat and host. These differences were largely driven by rare host-specific AM fungi that displayed near-complete turnover between forest types, while core AM fungal taxa were highly abundant and ubiquitous. The bipartite networks in the remnant forest were more specialized and hosts more specific than in the restored forest. Host-associated AM fungal communities nested within soil communities in both habitats, but only significantly so in the restored forest.Our results provide evidence that restored and remnant forests harbour the same core fungal symbionts, while rare host-specific taxa differ, and that geography, host identity and taxonomic resolution strongly affect the observed distribution patterns of these fungi. We suggest that host-specific interactions with AM fungi, as well as spatial processes, should be explicitly considered to effectively re-establish target host and symbiont communities.

Host plant richness and environment in tropical forest transformation systems shape arbuscular mycorrhizal fungal richness

“…While ASVs are likely overestimating AMF species, their d´values for specialization ranged from 0.2 to 0.5 in the roots of the analyzed plant species (Kajihara et al, 2022), i.e., were in a range similar to the values found here. In restored forests, d´was slightlybut significantlylower than in forest remnants (Kajihara et al, 2022), thus, also resembling the effects found here with lower d´(0.2) for ubiquitous AMF taxa and higher d( 0.3) for AMF taxa associated only to forest plants. Since these dv alues are closer to zero (no specialization) than to 1 (specialization) our data agree with the results of metaanalyses that AMF species may have a preference for certain plant communities rather than plant species (Hoeksema et al, 2010;Yang et al, 2012).…”

“…Santos et al, 2006;Torrecillas et al, 2012). For example, a deep sequencing effort of AMF species in roots from five native and one introduced plant species in a remnant and a restored forest on Hawaii resulted in the identification of 1766 amplicon sequencing variants (ASV) (Kajihara et al, 2022). While ASVs are likely overestimating AMF species, their d´values for specialization ranged from 0.2 to 0.5 in the roots of the analyzed plant species (Kajihara et al, 2022), i.e., were in a range similar to the values found here.…”

“…The number of AMF taxa detected in roots depends on the sequencing strategy and bioinformatic filtering as outlined elsewhere ( Davison et al., 2015 ; Vasar et al., 2017 ; Kajihara et al., 2022 ). Sequencing depths by Illumina or pyrosequencing is higher than by cloning sequencing used here.…”

“…Several studies found selectivity of AMF species for host plants ( Grime et al., 1987 ; Miller and Kling, 2000 ; Bever, 2002 ; Carrenho et al., 2002 ; Zhang et al., 2010 ), while others reported a lack of host specificity ( Clapp et al., 1995 ; Santos et al., 2006 ; Torrecillas et al., 2012 ). For example, a deep sequencing effort of AMF species in roots from five native and one introduced plant species in a remnant and a restored forest on Hawaii resulted in the identification of 1766 amplicon sequencing variants (ASV) ( Kajihara et al., 2022 ). While ASVs are likely overestimating AMF species, their d´ values for specialization ranged from 0.2 to 0.5 in the roots of the analyzed plant species ( Kajihara et al., 2022 ), i.e., were in a range similar to the values found here.…”

“…For example, a deep sequencing effort of AMF species in roots from five native and one introduced plant species in a remnant and a restored forest on Hawaii resulted in the identification of 1766 amplicon sequencing variants (ASV) ( Kajihara et al., 2022 ). While ASVs are likely overestimating AMF species, their d´ values for specialization ranged from 0.2 to 0.5 in the roots of the analyzed plant species ( Kajihara et al., 2022 ), i.e., were in a range similar to the values found here. In restored forests, d´ was slightly – but significantly – lower than in forest remnants ( Kajihara et al., 2022 ), thus, also resembling the effects found here with lower d´ (0.2) for ubiquitous AMF taxa and higher d´ (0.3) for AMF taxa associated only to forest plants.…”