There is high potential for the formation of common mycorrhizal networks between understorey and canopy trees in a mixed evergreen forest

Abstract

Summary 1The patterns of ectomycorrhizal (ECM) host specificity between understorey and canopy trees were investigated in three mixed evergreen forest stands in northern coastal California. ECM root tips from the dominant canopy ( Pseudotsuga menziesii ) and understorey ( Lithocarpus densiflora ) trees were sampled from 18 soil cores (six per stand) and identified using molecular techniques (PCR, RFLP, and DNA sequencing of the rDNA ITS region). 2 We found 56 ECM taxa; 17 on both hosts, 27 solely on Pseudotsuga and 12 on Lithocarpus . There were no significant differences in ECM taxon richness or diversity across stands, although ECM taxon richness was significantly higher on Pseudotsuga than Lithocarpus . ECM taxa similarity across stands was low. 3 Multiple-host ECM taxa had significantly higher abundance than single-host ECM taxa and 13 of the 17 multiple-host ECM taxa were present on both hosts within at least one core. Twelve of the 14 cores had at least one ECM taxon that was present on both hosts, although the specific taxon varied between cores and stands. In addition, shared ECM taxa often had unequal relative abundances on the two hosts. 4 Taken together, our results suggest that there is high potential for common mycorrhizal networks to form between Lithocarpus understories and Pseudotsuga canopies in mixed evergreen forests.

Strong effect of climate on ectomycorrhizal fungal composition: evidence from range overlap between two mountains

“…Our stand-scale analyses detected significant host effects at some sites, especially in gymnosperm-angiosperm mixed forests (Miyamoto,unpublished data;Supplementary Table S3), as in many previous studies (Ishida et al, 2007;Tedersoo et al, 2008;Smith et al, 2009). However, most EM fungi are assumed to be host generalists (Bruns et al, 2002), which is supported by numerous studies (Kennedy et al, 2003;Roy et al, 2008;Trocha et al, 2012;Bahram et al, 2013b). Therefore, although the host may influence the EM fungal community within a narrow range of climatic conditions at stand scales, the effect could be masked by more dominant determinants (e.g., climate) at larger spatial scales.…”

“…The host plant is regarded as one of the most important factors that influences EM fungal composition, especially at the stand scale, where hosts coexist in relatively narrow spatial and environmental ranges (Kennedy et al, 2003;Richard et al, 2005;Ishida et al, 2007;Tedersoo et al, 2008;Smith et al, 2009;Murata et al, 2013). However, isolating the host effect at larger spatial scales is difficult because the host composition changes with climatic conditions and geological history .…”

Ectomycorrhizal communities associated with silver fir seedlings (Abies alba Mill.) differ largely in mature silver fir stands and in Scots pine forecrops

“…According to the analysis of similarity, the ECM fungal communities on A. alba seedlings differed between fir and pine stands. Because common mycorrhizal networks (CMN) are present in forest soils (Kennedy et al 2003;Teste et al 2009), fir seedlings regenerating under a canopy of pine trees that are in close proximity to fir can be colonized by ECM fungi from mature silver fir trees in adjacent stands. However, in this case, because the pine and fir stands support different species of fungi, the seedlings in pine stands may be affected by pre-existing ECM communities of mature pine caused by the presence of CMN and spore banks.…”

Low diversity and high host preference of ectomycorrhizal fungi in Western Amazonia, a neotropical biodiversity hotspot

“…Sampling effect may also account for these differences, as host preference differs by host taxa in temperate ecosystems (Molina et al, 1992;Tedersoo et al, 2008). Nevertheless, the fungal community dominants are non-selective of their hosts in subalpine to temperate ecosystems of the Northern Hemisphere (Horton and Bruns, 1998;Kennedy et al, 2003;Richard et al, 2005;Ishida et al, 2007;Ryberg et al, 2009). In most ecosystems studied to date, host genus or even species substantially affect the community composition of EcM fungi by slight non-significant shifts in the frequency of individual species (Ishida et al, 2007;Morris et al, 2008).…”