A strong species–area relationship for eukaryotic soil microbes: island size matters for ectomycorrhizal fungi

Abstract

While the effects of habitat size and isolation have been successfully studied for macro-organisms, there is currently debate about their relative importance in explaining patterns of microbial species richness. In this study, we examine the species richness of a dominant group of eukaryotic soil microbes, ectomycorrhizal fungi, on 'tree islands' of constant age and host composition that range in size from < 10 to > 10,000 m(2). Our results show that ectomycorrhizal species richness is significantly reduced on smaller and more isolated tree islands, and the species-area slope that we observe (0.20-0.23) is similar to average slopes reported for macro-organisms. Additionally, species' occurrence patterns across tree islands and investment trends in fungal fruit bodies suggest that a trade-off between competition and dispersal could play an important role in structuring ectomycorrhizal assemblages.

Spatial scaling of functional gene diversity across various microbial taxa

“…However, as the authors indicated, the ARISA-defined OTU could also underestimate the number of fungal species, which could lead to lower z values. In addition, the estimated z value is substantially lower than the z values (0.20-0.23) for ectomycorrhizal fungi (7).…”

“…Knowledge about the spatial distribution patterns of biodiversity are critical to deciphering the forces shaping and maintaining biodiversity (1) and are of practical importance for predicting species extinction risk because of loss of habitat (1) and for designing reserves to protect biodiversity (1). Therefore, the spatial distribution patterns of biodiversity have received a great deal of attention in macrobial ecology (1), but only more recently in microbial ecology (3)(4)(5)(6)(7).…”

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

“…Comparable studies of temperate and tropical sites in the Northern and Southern Hemisphere reveal several-fold more species and lineages than Yasuni (Tedersoo and Nara, 2010). The level of richness compares better with a monodominant Coccoloba uvifera coastal forest in Cuba (U Kõ ljalg and L Tedersoo, unpublished data) and other island ecosystems (Supplementary Table S2; Peay et al, 2007;Tedersoo et al, 2007;L Tedersoo and A Sadam, unpublished data from São Tomé and Mount Cameroon). The relatively low EcM fungal diversity strongly contrasts with the peaking plant diversity, including high host species richness in the Yasuni 50-ha plot (26 species ;Valencia, 2004;Valencia et al, 2004), and challenges the hypothesis of a positive fungal diversity, host diversity relationship (Dickie, 2007), on a global scale.…”

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

“…In addition, EM fungal communities may be affected by climate and soil (Cox et al, 2010;Jarvis et al, 2013;Roy et al, 2013). Moreover, EM fungal communities often exhibit spatial structures (Lilleskov et al, 2004;Bahram et al, 2013a;Miyamoto et al, 2014), which may be driven by autocorrelations in environmental factors (Toljander et al, 2006;Tedersoo et al, 2012) or independently by fungal internal factors (e.g., dispersal; Peay et al, 2007). Thus, at larger regional and global scales, whether EM fungal communities are differentiated by hosts, environmental factors or geographical distance is less clear.…”