Ectomycorrhizal diversity and community structure in stands of Quercus oleoides in the seasonally dry tropical forests of Costa Rica

Most conservation efforts in seasonally dry tropical forests have overlooked less obvious targets for conservation, such asmycorrhizal fungi, that are critical to plant growth and ecosystem structure.We documented the diversity of ectomycorrhizal (EMF) and arbuscularmycorrhizal (AMF) fungal communities inQuercus oleoides (Fagaceae) inGuanacaste province, Costa Rica. Soil cores and sporocarpswere collected from regeneratingQ. oleoides plots differing in stand age (early vs late regeneration) during thewet season. Sequencing of the nuclear ribosomal ITS region in EMF root tips and sporocarps identified 37 taxa in the Basidiomycota; EMFAscomycotawere uncommon. The EMF community was dominated by one species (Thelephora sp. 1; 70%of soil cores), more than half of all EMF species were found only once in an individual soil core, and there were few conspecific taxa.Most EMF taxawere also restricted to either Early or Late plots. Levels of EMF species richness and diversity, andAMF root colonizationwere similar between plots. Our results highlight the need for comprehensive spatiotemporal samplings of EMF communities inQ. oleoides to identify and prioritize rare EMF for conservation, and document their genetic and functional diversity.