Seasonal dynamics of ectomycorrhizal fungi in alpine habitats

Ectomycorrhizal (ECM) fungi are essential for establishment and maintenance of ECM plant communities. Recent work has shown that fungal biomass varies seasonally in alpine tundra soils with Kobresia myosuroides vegetation, reaching maximum annual levels during late winter under the snow pack (Schadt et al. 2003). But seasonal dynamics of ECM fungi, one substantial part of the soil fungal biomass, are still poorly understood. The aims of the proposed study are to improve our understanding (i) of the seasonal and developmental dynamics of ECM fungi in the soil and on the roots, (ii) of the ecological function of different fungal life forms (mycelia and spore banks) in the soil, and (iii) of the interactions of soil fungal communities with different host plants. The first work package (WP) is a seasonal monitoring of the mycobionts of three co-occurring alpine ECM host plants (Bistorta vivipara, Kobresia myosuroides; Salix herbacea), combining molecular biology techniques with ECM morphotyping. We are especially interested in how the fungal species composition on mycorrhized roots is linked to the (presumed) shifts of the soil fungal community. Therefore, the second WP is a seasonal monitoring of the ECM fungal communities present in the soil, and an estimation of fungal biomass. A promising, new strategy for the study of the soil fungal community is to separately investigate actively growing mycelia and dormant spore bank. This can be achieved by the application of soil-washing techniques (Parkinson & Williams, 1960) to half of each sample before molecular analyses. The third WP is identification and quantification of fungal fruit bodies, with the aim to investigate if they are indicators for underground fungal communities in primary successional habitats. Comparison of the soil fungal community with the mycorrhizal status of ECM host plants will provide evidence of mechanisms affecting the mycorrhization processes. We will be able to attribute the degree of successful mycorrhization to the different fungal life forms (spores, mycelia). With the comprehensive investigations planned in this study, we can address how soil and root fungal communities interact, and how this fungal below ground bio-complexity changes during the season. This will add to our understanding on establishment, developmental dynamics and seasonal succession of ECM fungi in general.

Ectomycorrhizal (ECM) fungi are essential for establishment and maintenance of ECM plant communities. Recent work has shown that fungal biomass varies seasonally in alpine tundra soils with Kobresia myosuroides vegetation, reaching maximum annual levels during late winter under the snow pack (Schadt et al. 2003). But seasonal dynamics of ECM fungi, one substantial part of the soil fungal biomass, are still poorly understood. The aims of the proposed study are to improve our understanding (i) of the seasonal and developmental dynamics of ECM fungi in the soil and on the roots, (ii) of the ecological function of different fungal life forms (mycelia and spore banks) in the soil, and (iii) of the interactions of soil fungal communities with different host plants. The first work package (WP) is a seasonal monitoring of the mycobionts of three co-occurring alpine ECM host plants (Bistorta vivipara, Kobresia myosuroides; Salix herbacea), combining molecular biology techniques with ECM morphotyping. We are especially interested in how the fungal species composition on mycorrhized roots is linked to the (presumed) shifts of the soil fungal community. Therefore, the second WP is a seasonal monitoring of the ECM fungal communities present in the soil, and an estimation of fungal biomass. A promising, new strategy for the study of the soil fungal community is to separately investigate actively growing mycelia and dormant spore bank. This can be achieved by the application of soil-washing techniques (Parkinson & Williams, 1960) to half of each sample before molecular analyses. The third WP is identification and quantification of fungal fruit bodies, with the aim to investigate if they are indicators for underground fungal communities in primary successional habitats. Comparison of the soil fungal community with the mycorrhizal status of ECM host plants will provide evidence of mechanisms affecting the mycorrhization processes. We will be able to attribute the degree of successful mycorrhization to the different fungal life forms (spores, mycelia). With the comprehensive investigations planned in this study, we can address how soil and root fungal communities interact, and how this fungal below ground bio-complexity changes during the season. This will add to our understanding on establishment, developmental dynamics and seasonal succession of ECM fungi in general.