Ecology of fungal root endophytes in the boreal forest
Although the boreal forest is Canada's largest ecosystem, our understanding of the diversity and function of the organisms below the boreal soil surface is limited. However, it is the interactions among these organisms that drives soil nutrient cycling, as well as a variety of other critical ecosystem processes. It is likely that the roots of boreal forest plants harbour a highly diverse, but as yet unknown, community of ecologically important endophytic symbionts. Until recently, however, information on this group has surfaced only incidentally, during research targeting other organisms. DNA-based approaches are revealing the true diversity residing in boreal forest soils. Information on the functional relationships between fungal root endophytes and their host plants will be invaluable for modeling carbon allocation patterns in forest ecosystems. The influence of root endophytes on host plant access to recalcitrant nutrient sources will also improve our understanding of the key microbial nutrient cycling processes necessary for plant growth.
The role of root symbionts in forest migration
As part of the international Polar Year, we are studying the role of ectomycorrhizal fungi (ECMF) in the upward migration of the boreal forest into northern areas currently supporting arctic tundra. As these fungal symbionts enhance plant nutrient acquisition, water absorption and resistance to disease and frost they are critical for conifer establishment in high elevation and high latitude habitats. The availability of ECMF to conifer seedlings above the present tree line is likely governed by the presence of other woody plants such as Betula, Salix and Arctostaphylos, which act as alternate hosts for compatible ECMF species. We are currently assessing the availability of ECMF to black spruce seedlings in the main plant communities found above tree line in the Mealy Mountains.
Use of root symbionts in land reclamation
Heavy metals and arsenic are common contaminants of abandoned mine sites. These compounds inhibit plant growth and therefore represent a serious challenge land restoration efforts. Because these toxins cause stunting and abortment of fine roots, plants grow poorly due to their inability to absorb mineral nutrients from the soil. We are therefore assessing the effectiveness of microbial root symbionts to ameliorate these toxic effects and restore the natural course of plant succession on abandoned mine sites.
Lignocellulose Decomposition of wood due to wood-inhabiting fungi
Coarse woody debris supports large numbers of saproxylic fungal species. However, most of the current knowledge comes from Scandinavia and studies relating the effect of stand or log characteristics on the diversity and composition of decomposer fungi have not been conducted in Northeastern Canada. Logs from five tree species were sampled along a decomposition gradient in nine stands representing three successional stages of the boreal mixed forest of Northwestern Quebec, Canada. Using a molecular fingerprinting technique, we assessed fungal community Shannon-Weaver diversity index, richness, and composition. We used linear mixed models and multivariate analysis to link changes in fungal communities to log and stand characteristics. We found a total of 33 operational taxonomic units (OTUs) including an indicator species for balsam fir (similar to Athelia sp.) and one found only in aspen stands (similar to Calocera cornea). Spruce logs supported to the highest fungal Shannon-Weaver diversity index and OTU number. Our results support the hypothesis that log species influences fungal richness and diversity. However, log decay class does not. Stand composition, volume of coarse woody debris, and log chemical composition were all involved in structuring fungal communities. Maintaining the diversity of wood-decomposing communities therefore requires the presence of dead wood from diverse log species.
Biogas production from anaerobic digestion of wood-derived materials
Along side of Biogas Energy Inc. (BEI), we are determining the potential of wood-derived waste materials for the production of biogas. Both waste wood and boxboard are currently composted, emitting carbon dioxide directly to the atmosphere. However, anaerobic digestion of these materials can result in the production of a mixture of carbon dioxide and methane (biogas), useful for heating and the generation of electricity. Biogas production from waste lignocellulosic materials could help offset the use of non-renewable fossil fuels.