Differential hypogeous sporocarp production from Nothofagus dombeyi and N. pumilio forests in southern Argentina

Abstract

Mycorrhizal fungi that form hypogeous sporocarps are an important component of the temperate forest soil community. In many regions, such as the Nothofagus forest in the Patagonian Andes, this group of fungi has been poorly studied. Here we examined the spring and autumn community composition of “sequestrate fungi”, based on sporocarp production in pure forests of Nothofagus dombeyi (evergreen) and N. pumilio (deciduous). We investigated the possible relationships between these communities and environmental factors over 2 y. The rarefaction curves and the minimal richness estimates converged at nearly the same level for each forest type, and the asymptotes suggested that the sampling effort was sufficient to capture most of the hypogeous sporocarp richness in these forest stands. In total 27 species were recovered. Basidiomycota, Ascomycota and Glomeromycota respectively accounted for nine, two and one genera. Species richness of hypogeous sporocarps varied in relation to forest type but not to season (fall and spring), whereas sporocarp biomass varied according to an interaction between season and forest type. Species richness and sporocarp biomass were positively correlated with rainfall and negatively correlated with altitude. In addition sporocarp species richness was positively related to number of trees per transect. We found that two different forest stands, each dominated by different species of Nothofagus, exhibited different hypogeous sporocarp communities.

• biomass
• fruit bodies
• hypogeous richness
• Nothofagus forest
• Patagonia

Acknowledgments

This study was supported by CONICET, PIP N° 6193, Argentina.

Dr Daniel Luoma, Dr Leho Tedersoo and an anonymous reviewer provided very helpful comments that enhanced the quality of the manuscript. Dr Laura Domínguez helped with taxa identification. Dr Colwell provided helpful advice about the ESTIMATES program. The Nahuel Huapi National Park personnel facilitated sampling activities within the park. E.N. and C.U. are researcher and S.L. fellow of Conicet (National Research Council of Argentina)