Fungal Diversity & Isotope Patterns

Just published is a great new paper I had the priveledge of contributing to: Global diversity and geography of soil fungi by Leho Tedersoo et al. Science 346, (2014); DOI: 10.1126/science.1256688 

Also see the accompanying Perspectives article independently writen by my current postdoctoral advisor and colleague at SLU, David A. Wardle and Bj√∂rn D. Lindahl Science 346, 1052 (2014); DOI: 10.1126/science.aaa1185 

As well as the news release on the SLU website: http://www.slu.se/en/about-slu/fristaende-sidor-eng/whats-on/news/2014/11/disentangling-global-soil-fungal-diversity/

A common problem for fungal ecologists is the accurate assignment of nutritional mode to a given sporocarp (mushroom).  Using a discriminant model based on collector categorizations, along with δ13C and δ15N values from sporocarps, I demonstrated that regardless of geographical location one can confidently assign nutritional modes to fungi. This is interesting given that there are strong global graidents in plant and soil δ15N values.

Mayor, J.R., Schuur, E.A.G. & Henkel, T.W. (2009). Elucidating the nutritional dynamics of fungi using stable isotopes. Ecol Lett, 12, 171–183. PDF

 

Birkebak, J.M., Mayor, J.R., Ryberg, M. & Matheny, P.B. (2013). A systematic, morphological and ecological overview of the Clavariaceae (Agaricales). MycologiaPDF

 

Furthormore, I recently published a new synthesis of relative ecosytem 15N patterns from around the world:

Abstract

Ectomycorrhizal (EcM)-mediated nitrogen (N) acquisition is one main strategy used by terrestrial plants to facilitate growth. Measurements of natural abundance nitrogen isotope ratios (denoted as d15N relative to a standard) increasingly serve as integrative proxies for mycorrhiza-mediated N acquisition due to biological fractionation processes that alter 15N:14N ratios. Current under- standing of these processes is based on studies from high-latitude ecosystems where plant produc- tivity is largely limited by N availability. Much less is known about the cause and utility of ecosystem d15N patterns in the tropics. Using structural equation models, model selection and isotope mass balance we assessed relationships among co-occurring soil, mycorrhizal plants and fungal N pools measured from 40 high- and 9 low-latitude ecosystems. At low latitudes 15N-enrichment caused ecosystem components to significantly deviate from those in higher lati- tudes. Collectively, d15N patterns suggested reduced N-dependency and unique sources of EcM 15N-enrichment under conditions of high N availability typical of the tropics. Understanding the role of mycorrhizae in global N cycles will require reevaluation of high-latitude perspectives on fractionation sources that structure ecosystem d15N patterns, as well as better integration of EcM function with biogeochemical theories pertaining to climate-nutrient cycling relationships. 

Mayor, J.R.; Bahram, M.; Henkel, T.; Beugger, F.; Pritsch, K.; Tedersoo, L. (2014) Ectomycorrhizal impacts on plant nitrogen nutrition: emerging isotopic patterns, latitudinal variation, and hidden mechanisms. Ecol Lett, doi:10.1111/jeu.12187