Massicotte, Hugues , Tackaberry, Linda E. , Green, D. Scott .
Relocation success of whitebark pine under genetic, soil microbial and elevation shifts: soil impacts on seedling growth traits and mycorrhizal communities.
Whitebark pine (WBP, Pinus albicaulis Engelm.) is a high elevation conifer limited to subalpine/treeline habitats in western North America. Vital to slope stabilization, plant succession and watershed protection, it is experiencing dramatic declines due to white pine blister rust and the mountain pine beetle. In addition, predicted climate warming may favour competition by more shade-tolerant high elevation species. Currently, WBP is Blue-listed in British Columbia and, to survive, it may need to expand naturally (or by intervention) into higher alpine areas, or north in latitude beyond its present range. WBP forms obligate root-fungal symbiosis (ectomycorrhizas=ECM) and successful relocation should depend on suitable soil microbial processes as well as abiotic factors. A greenhouse bioassay was established to explore limits of location and population sensitivity on successful establishment, using soils from multiple locations (climatically different sites– McBride Peak, Perkins Peak) and geographically distinct WBP populations (five north-south and east-west seedlots). Seed (total=1392) was sown into subalpine soils (specifically, those from WBP stands) and alpine soils (beyond established treeline) to assess soil impacts on seedling growth adaptive traits and ECM communities. To promote germination, growth, and ECM formation, we used an extended cold seed stratification followed by scarification, 25/20˚C day/night temperatures, extended photoperiod (20 hr), and no fertilization. Soils were analysed for pH, total C and N, P, exchangeable cations and CEC. At five months, a sub-sample of seedlings was measured for growth using stem basal diameter, shoot and root dry weights, and root/shoot mass ratios. ECM colonization was assessed using descriptive morphology methods (light microscopy). Early findings are discussed within the context of how WBP may respond to natural or assisted re-establishment under genetic, soil microbial, and elevation shifts. Proactive management in high elevation forests might sustain threatened species and ecosystem function.
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1 - University of Northern British Columbia, Ecosystem Science and Management Program, 3333 University Way, Prince George, B.C., V2N 4Z9, Canada
adaptive growth traits
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Cottonwood C/Snowbird Center
Date: Wednesday, July 29th, 2009
Time: 4:15 PM