Community structure of ectomycorrhizal fungi in a Pinus muricata forest: above- and below-ground views

Abstract

We examined the species diversity of an ectomycorrhizal community in natural stands of bishop pine (Pinus muricata D. Don) to determine the correspondence between above- and below-ground views of species composition, spatial frequency, and abundance. We addressed this question by simultaneously sampling fruit bodies and ectomycorrhizae over a 4-year period. By using molecular methods based on polymerase chain reaction, we were able to identify the fungal symbionts directly from mycorrhizae in nearly all of the mycorrhizal morphotypes we found. Most species were either rare or low in abundance. Among the common species we observed three patterns: (i) some species, such as Russula xerampelina s.l. and Amanita francheti were well represented both above- and below-ground; (ii) some common fruiting species such as Suillus pungens were rare components belowground; (iii) some species that were common as mycorrhizae were represented poorly or unrepresented in the aboveground fruiting record. The latter was the case for Russula amoenolens, thelephoroid types (i.e., Tomentella sublilacina and thelephoroid-2), and a boletoid type. These results show that (i) the pattern of resource allocation to production of fruit bodies versus ectomycorrhizae varied among species, and (ii) the correspondence between above- and below-ground is imprecise at best at the community level. Keywords: mycorrhizal types, basidiocarps, sporocarps, fungal community, ecology of fungi, PCR, molecular ecology.