Mycorrhizal responses to soil warming and disturbance in temperate forests of the eastern United States

It is predicted that the planets global temperature will continue to increase and that more disturbance events will occur. These factors are expected to affect forest productivity as well as soil respiration, decomposition, mineralization, and mycorrhizal activity. The response of ectomycorrhiza (EM) and arbuscular mycorrhiza (AM) to soil warming and disturbance was determined by seedling growth, fungal colonization amounts, foliar nitrogen (N) and 15N content, and EM fungal species diversity. It was hypothesized that EM fungal colonization, foliar 15N, and EM fungal diversity would decrease with increasing soil temperatures and that AM species would be unaffected. The first two hypotheses were not supported but EM fungal diversity was decreased. It was also hypothesized that disturbance would result in greater fungal colonization of seedlings receiving more light but decrease EM fungal diversity. Results demonstrated that support of these hypotheses is tree species dependent.