Spatial and Temporal Dimensions of the Rhizopogon Spore Bank

外生菌根(EM)孢子库是植物-真菌群落生态学的一个基本组成部分，但研究很少。EM孢子库可以为严重干扰后的树木更新提供必要的接种物，并可能促进树木入侵非林区。在许多西北美洲松林生态系统中，根际植物是孢子库中含量最丰富的成分，在一些森林边界环境中，它们几乎是整个孢子库的组成部分。本文着重了解在循环火灾和松树更新的背景下，根际孢子库的时空动态。提出了一个概念模型，并提出了与该模型相关的五个具体假设。这些假设集中在孢子寿命和根部扩散上的差异测量的参数包括：i)森林边缘地带孢子阴影的空间格局，ii)向这些区域的当前扩散速度和方式，iii)三个关键根际植物的孢子寿命和v)复合原生孢子库的寿命。将结合生物测定、分子生态学、大规模空间采样和种子库生态学的技术对假设进行验证。工作涉及群落生态的一个重要但基本未被研究的组成部分(即EM孢子库)，并提供了一个类似的系统来测试为植物种子库开发的想法。这项工作的更广泛的影响是它与森林更新和扩张的直接关系；预测EM孢子库的空间和时间范围的能力将为森林管理者提供一种合理的方法来评估在高度干扰的系统中接种EM的可能性。

Ectomycorrhizal (EM )spore banks are a fundamental,but poorly studiedcomponent,of plant-fungal community ecology.EM spore banks can providethe inoculum necessary for tree recruitment following severe disturbance andmay facilitate tree invasion into bordering non-forested areas.Rhizopogon speciesare the most abundant component of spore banks in many western NorthAmerican pinaceous ecosystems,and in some forest-border settings they appearto be virtually the entire spore bank.This proposal is focused on understandingthe spatial and temporal dynamics of Rhizopogon spore banks in the context ofcyclic fire and pine regeneration.A conceptual model for these interactions isproposed,and five specific hypotheses related to the model are tested.Thesehypotheses focus on differences in spore longevity and spore dispersal amongRhizopogon species,and on differences in mode and frequency of dispersal withinmature-forests and post-fire forests.Measured parameters include:i)spatialpattern of the spore shadow in forest border zones,ii)current dispersal rates andmodes into these zones,iii)spore longevity of three key Rhizopogon species andiv)longevity of complex native spore banks.Hypotheses will be tested bycombining the techniques of bioassays,molecular ecology,large-scale spatialsampling,and seed bank ecology.The work addresses a crucial,but essentiallyunstudied,component of community ecology (i.e.,EM spore banks),andprovides an analogous system in which to test ideas developed for plant seedbanks.The broader impacts of this work are its direct relationship to forestregeneration and expansion;the ability to predict the spatial and temporal extentof the EM spore banks will provide forest managers with a rational way to assessthe likelihood of EM inoculum in highly disturbed systems.