Collaborative Research: Dispersal Limitation as a Primary Factor in Determining Ectomycorrhizal Community Structure

Proposal Title: Collaborative Research: Dispersal Limitation as a Primary Factor in

Determining Ectomycorrhizal Community Structure

Institution: University of California-Berkeley

Abstract Date: 12/04/07

Ectomycorrhizal fungi are obligate mutualists with temperate forest trees such as pines,

oaks, aspens, and birch. These fungi provide mineral nutrients to the trees in exchange

for sugars, and trees require them for growth and survival. Following severe

disturbance such as forest fires or logging, trees need to reestablish their relationships

with mycorrhizal fungi in order to survive. Prior work has shown that these fungi arrive

in an ordered sequence, or 'succession', after such disturbances. A new model is

proposed to explain this observed pattern through differences in spore dispersal and

competitive interactions among mycorrhizal fungi. Four key predictions of this model

concerning limitations to aerial spore dispersal and effect of tree root density on fungal

competition will be tested through a combination of field sampling and manipulative

growth-chamber experiments. The broader impacts of this work are that it will help us

understand an essential biotic process necessary for tree establishment, and will build a

foundation of basic ecological knowledge for an important group of understudied

organisms. Training of graduate and undergraduate students will be an important

component of this research. In addition this work takes advantage of its location within

Point Reyes National Seashore by feeding back into management decisions within the

park and through outreach efforts directed towards public education.