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Brendan Twieg

M.Sc. candidate, Forest Sciences, UBC
Supervised by Dan Durall and Suzanne Simard

Succession of Ectomycorrhizae on paper birch and Douglas-fir

Similar forests of different ages have been found to support distinct ectomycorrhizal (ECM) fungal communities (Smith et al 2002, Visser 1995). Paper birch and Douglas-fir are important early- to late-successional species in the Interior Cedar Hemlock biogeoclimatic zone in British Columbia. I am using a chronosequence of forests at ages from 5 to 105 years since stand initiation to examine the ectomycorrhizal fungal communities on paper birch and Douglas- fir. This will allow us to quantify the relative dominance of different ECM fungal groups at different forest ages.

Questions we hope to answer:

  • Does ECM fungal community composition shift according with the four main ecological succession stages of these forests?
  • Do certain ECM fungal groups not appear until a certain successional stage?
  • Do the numbers and proportions of ECM fungi common to both tree hosts change over time?
  • If the answer is "yes" to any or all of those questions, which site factors are most closely correlated to these phenomena?
  • Does clearcutting result in the same pattern of early-ECM succession as wildfire?

Results so far:

  • We have recognized 50 unique genotypes from 111 DNA sequences thus far.
  • Preliminary analyses show distinct shifts in the relative dominance of Piloderma, Russula, and Rhizopogon-Suillus spp. as these stands mature.
  • The potential for common ECM networks to exist between Douglas-fir and paper-birch is comparatively low in 5 year-old stands, partially due to Rhizopogon dominance in these stands. Rhizopogon morphotypes were not found associated with birch.
  • Although no differences have been detected between stand initiation types of the same age, we believe analysis of the complete molecular data and multivariate analyses will detect differences.

Smith, J.E., R. Molina, M.M.P. Huso, D.L.Luoma, D. McKay, M.A. Castellano, T. Lebel, and Y. Valachovic. 2002. Species richness, abundance, and composition of hypogeous and epigeous ectomycorrhizal fungal sporocarps in young, rotation- age, and old-growth stands of Douglas-fir (Pseudotsuga menziesii) in the Cascade Range of Oregon, U.S.A. Can. J. Bot. 80: 186-204.

Visser, Suzanne. 1995. Ectomycorrhizal fungal succession in jack pine stands following wildfire. New Phytologist 129: 389-401

Last reviewed shim5/8/2013 6:27:35 PM