Soil factors influencing ectomycorrhizal sporome distribution in neotropical forests dominated by Pinus montezumae, Mexico

Soil factors influencing ectomycorrhizal (ECM) sporome distribution in neotropical forests dominated by Pinus montezumae were examined at Sierra Chichinautzin, Mexico. Study sites were located on three volcanoes of different ages and ECM sporomes were collected during three consecutive years. Inocybe and Laccaria species were preferentially found at the youngest site, while Tricholoma and Russula species showed a more abundant distribution at the oldest site. Total sporome richness was negatively correlated with carbon (C) and nitrogen (N) contents in the soil organic horizon. Canonical correspondence analysis (CCA) was used to investigate the relationships between sporome species and soil variables. The CCA biplot showed that Amanita rubescens, I. fastigiata, and I. geophylla had a strong positive relationship with soil C and N contents, whereas Inocybe sp.4 was negatively related to these variables. This indicates an intra-generic variability in fungal responses to soil factors. The measured soil nutrients influenced species composition patterns, and the differences in sporome distribution evidenced a large degree of community specialization along the soil quality gradient. Together, these data contribute to a better understanding of the ecology of macrofungi in neotropical forests.