Spatial and Temporal Dimensions of the Rhizopogon Spore Bank

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Ectomycorrhizal (EM )spore banks are a fundamental,but poorly studied component,of plant-fungal community ecology.EM spore banks can provide the inoculum necessary for tree recruitment following severe disturbance and may facilitate tree invasion into bordering non-forested areas.Rhizopogon species are the most abundant component of spore banks in many western North American pinaceous ecosystems,and in some forest-border settings they appear to be virtually the entire spore bank.This proposal is focused on understanding the spatial and temporal dynamics of Rhizopogon spore banks in the context of cyclic fire and pine regeneration.A conceptual model for these interactions is proposed,and five specific hypotheses related to the model are tested.These hypotheses focus on differences in spore longevity and spore dispersal among Rhizopogon species,and on differences in mode and frequency of dispersal within mature-forests and post-fire forests.Measured parameters include:i)spatial pattern of the spore shadow in forest border zones,ii)current dispersal rates and modes into these zones,iii)spore longevity of three key Rhizopogon species and iv)longevity of complex native spore banks.Hypotheses will be tested by combining the techniques of bioassays,molecular ecology,large-scale spatial sampling,and seed bank ecology.The work addresses a crucial,but essentially unstudied,component of community ecology (i.e.,EM spore banks),and provides an analogous system in which to test ideas developed for plant seed banks.The broader impacts of this work are its direct relationship to forest regeneration and expansion;the ability to predict the spatial and temporal extent of the EM spore banks will provide forest managers with a rational way to assess the likelihood of EM inoculum in highly disturbed systems.