Ecological indicators of Tuber aestivum habitats in temperate European beech forests

- Central/temperate European beech forests show vegetation correlates with T. aestivum.
- T. aestivum is associated with specific shrubs in addition to known host species.
- Floristic composition beyond known hosts is a good indicator of T. aestivum habitat.
- Ecological indicator values elucidate T. aestivum habitat requirements.

Although Tuber aestivum is widely distributed across Europe, little is known about its biology and ecology. We assess the vegetation composition of wild T. aestivum sites and use this information to characterise suitable habitats in Fagus sylvatica, Carpinus betulus and Ostrya carpinifolia (FCO) forests. Plant species composition at 16 naturally colonised T. aestivum sites in southwestern Germany and Switzerland was compared with that of 232 reference sites in Swiss FCO forest communities. The vegetation composition of truffle sites exhibits a high proportion of herb and shrub species that are indicators of a warm and dry climate, alkaline soil, and open tree canopy and thus typically occur in thermophilous FCO communities on calcareous bedrock. We conclude that T. aestivum is associated with a set of key species in addition to known host species. Based on their floristic composition, we identified FCO forest communities with high and low suitability for T. aestivum.