Long‐term increase in nitrogen supply alters above‐ and below‐ground ectomycorrhizal communities and increases the dominance ofRussulaspp. in a temperate oak savanna

Abstract

Summary• Here we examine the effects of increased nitrogen (N) supply on the ectomycorrhizal fungal communities of a temperate oak savanna.• In a 16-yr N-addition experiment in which replicate 1000 m 2 plots received 0, 5.4 or 17 g N m − 2 yr − 1 , ectomycorrhizal sporocarp production was measured in the 14th, 15th and 16th year of fertilization. Ectomycorrhizal fungi (EMF) colonizing roots were examined by morphotyping-PCR-RFLP and sequence analysis in the 14th and 15th year of fertilization.• Total sporocarp richness was reduced by > 50% in both fertilization treatments in all 3 yrs, whereas Russula spp. produced approx. five times more sporocarps with 17 g N m − 2 yr − 1 . Below-ground, treatment-scale species richness and species area curves were lower with 17 g N m − 2 yr − 1 but richness, diversity indices and evenness at smaller spatial scales were not. Dominant fungi colonizing roots included Cenococcum geophilum , common in all treatments, Cortinarius spp., dominant in unfertilized plots, and Russula spp., dominant with 17 g N m − 2 yr − 1 .• Communities of EMF in this temperate deciduous ecosystem responded to N addition similarly to those of coniferous ecosystems in that increased N supply altered EMF diversity and community composition but differently in that dominance of Russula spp. increased.

Variation in ectomycorrhizal fungal communities associated with Oreomunnea mexicana (Juglandaceae) in a Neotropical montane forest

“…Temperate Russula, particularly from the subsection Foetentineae, tend to inhabit more fertile habitats with relatively higher N availability (Avis et al 2003;Avis et al 2012) and have been reported to increase in abundance in response to N fertilization in permanent plots (N addition of 5.4 or 17 g N m −2 year −1 in oak savanna; Avis et al 2003). Several authors have also noted that EM fungi associated with N-rich habitats may form less beneficial or parasitic relationships with their hosts (Johnson et al 1997;Egger and Hibbett 2004;Avis 2012).…”

“…In contrast, all of the 14 species of Cortinarius observed here were found infecting root tips at the low fertility/high rainfall sites. Some Cortinarius species have been shown extract N from organic sources under conditions of low N availability (Taylor et al 2000;Lilleskov et al 2002;Avis et al 2003). More research on functional traits may help us understand the influence of fertility and rainfall on fungal community composition, and its effect on associated plant communities.…”

“…Given that this genus is an important component of many EM fungal communities in the tropics (e.g., Peay et al 2010;Smith et al 2011;Tedersoo et al 2011) and appears to shift in community composition with changes in soil N availability (Lilleskov et al 2002;Avis et al 2003;Avis et al 2008), it was chosen to test hypotheses concerning phylogenetic diversity. To augment data on Russula distribution obtained from root tips, Russula fruiting bodies were collected every 2 weeks throughout the study period from January to July 2012 along four 50×4 m transects in each site.…”

Ectomycorrhizal communities of Quercus garryana are similar on serpentine and nonserpentine soils

“…The most abundant and most frequent species of ectomycorrhizas associated with oaks on serpentine soils were the very common fungal species associated with oaks on all soils world wide: C. geophilum, an asexual Ascomycota with sclerotia; hypogeous Ascomycota (Tuber, Genea, Gilkeya, and other Pezizales); crust-forming resupinate Basidiomycota (Sebacina Avis et al 2003;Valentine et al 2004;Moser et al 2005;Richard et al 2005;Walker et al 2005;Frank et al 2006b). Serpentine soils supported extensive mycorrhizal communities.…”

Enigmatic Sebacinales

“…In ECM species of the Minnesota oak savanna, Quercus ellipsoidalis and Q. macrocarpa, Avis et al (2003) found Sebacina spp. and Tremellodendron pallidum as mycobionts.…”