Abstract Detail

Mycological Section

Cheeke, Tanya E. [1], Phillips, Richard P. [1], Kuhn, Alexander L. [2], Rosling, Anna [3], Bever, James D. [1], Fransson, Petra [4].

Mycelial production and standing fungal biomass are higher in temperate hardwood forests dominated by ectomycorrhizal trees than in forests dominated by arbuscular mycorrhizal trees.

Mycorrhizal mycelia are the dominant pathway through which nutrients are transported to trees and plant-derived carbon (C) enters forest soils. While much is known about the role mycorrhiza play in the transfer of C for nutrients, much less is known about these dynamics in stands dominated by tree species that associate with arbuscular mycorrhizal (AM) fungi vs. those that associate with ectomycorrhizal (ECM) fungi. We quantified fungal mycelia production, fungal/bacterial ratios, and the activity of five extracellular enzymes across a gradient driven by tree species and their mycorrhizal associates in three temperate hardwood forests in central Indiana, USA. Free and total ergosterol were used to measure active and total fungal biomass; quantitative PCR was used to determine fungal/bacterial ratios; and potential enzyme activity was used to evaluate seasonal variation in C, N, and P acquiring enzymes in plots dominated by AM-associated trees, ECM-associated trees, and a mixture of AM-ECM trees. We found strong convergence in the degree to which the abundance of AM and ECM trees in a plot influenced fungal dynamics, as all three sites showed similar patterns across their respective “mycorrhizal gradients”. Over the course of the growing season, plots dominated by ECM trees had nearly three times more standing fungal biomass than plots dominated by AM trees, and over 1.5 times more hyphal production. Fungal/bacterial ratios increased with increasing dominance of ECM-associated trees in all sites and across all seasons, and acid phosphatase activity was higher in ECM plots while peroxidase activity was higher in AM-plots. This study suggests that decomposition processes and nutrient availability in temperate hardwood forests vary with the dominant tree species in a stand. Understanding the role of mycelial production and activity on soil nutrient availability is critical for predicting how forest ecosystems might respond to environmental perturbations such as climate change, where range shifts in dominant tree species are predicted to occur.

1 - Indiana University, Department of Biology, 1001 East Third Street, Bloomington, IN, 47405-7005, USA
2 - State University of New York , College of Environmental Science and Forestry, 235 Fellows Ave., Syracuse, NY, 13210, USA
3 - Uppsala University, Department of Evolutionary Biology, Norbyägen 18D, Uppsala, 75236, Sweden
4 - Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, Skoglig mykologi och växtpatologi, Box 7026, Uppsala, 750 07, Sweden

Keywords:
Fungi
mycorrhiza
deciduous forest
ectomycorrhizal fungi
arbuscular mycorrhizal fungi.

Presentation Type: Oral Paper:Papers for Sections
Session: 22
Location: Salon 1/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:00 PM
Number: 22006
Abstract ID:361
Candidate for Awards:None