EVOGENE Extra Seminar - Isotopic Explorations of Fungal Functioning in Ecosystems

Fungi are ubiquitous in terrestrial ecosystems, with many either being key decomposers (saprotrophs) or forming symbioses with many of the dominant plants of temperate, boreal, and tundra ecosystems (ectomycorrhizal fungi). In this latter function, fungi receive carbon as sugars and in return supply nutrients to their host plants, with fungi differing greatly in their exploration strategies and enzymatic capabilities. Here, we explore fungal functioning using stable isotope (C and N) and radiocarbon measurements, including: (1) saprotrophic lawn fungi as integrators of competition between C₃ and C₄grasses in lawns, (2) wood decay fungi partitioning resources among species based on the age of the wood being assimilated, (3) fungivorous small mammals preserving a signal of organic nitrogen uptake by fungi in their hair, and (4) linking exploration type in ectomycorrhizal fungi to enzymatic capabilities, carbon demand, and where fungi are active in the soil profile.