PARENT SESSION
Oral Session #43: Soil Ecology: Mycorrhizae and Roots. Presiding: W. Stock.
Wednesday, August 8, 2001. 8:00 AM to 12:15 PM. Hall of Ideas F.
Ectomycorrhizal fungal diversity in four North American forests and the effect of nitrogen fertilization.
Lansing, Jennifer 1, Allen, Michael2, Deutschman, Douglas1, 1 2
ABSTRACT- The ectomycorrhizal (ECM) fungal communities of four North American forest vegetation types were assessed to gain basic knowledge of the below-ground ECM community and diversity. A manipulative nitrogen fertilization field experiment on mature stands was performed to investigate the effects of fertilization. The four sites: balsam poplar (Populus balsamifera), AK; red oak (Quercus rubra), GA; red pine (Pinus resinosa), MI; and pinyon pine (Pinus edulis), NM were fertilized with 100kgN/ha/yr and the ECM community was assessed using a combination of morphotyping and RFLP analysis of the rDNA ITS (internal transcribed spacer) region. Each site had a greater richness of ECM fungi at the plot level than at the level of an individual soil core with each plot containing at least five times the number of ECM types. The site with the least richness was the red oak with an average plot richness of 20 ECM types and an average soil core richness of 5. At the pinyon pine site there was an average richness of 25 ECM types per plot and an average richness of 5 per tree. The balsam poplar and red pine sites had the greatest richness. At the balsam poplar site the average plot richness was 40 ECM types with an average soil core richness of 8. Red pine had 45 ECM types with an average of 8 types per soil core. Fertilization did not affect ECM richness but did result in community differences and shifts in the dominance of certain ECM species.
KEY WORDS: ectomycorrhizal fungi, diversity, nitrogen fertilization