Belowground ectomycorrhizal communities in three Norway spruce stands with different degrees of decline in the Czech Republic

Abstract

We investigated the ectomycorrhizal communities on the roots of adult trees and seedlings associated with three Norway spruce stands in the Czech Republic using morphological and molecular tools. The stands had different degrees of forest decline due to air pollution. The aims of the study were to obtain information about the belowground ectomycorrhizal community in a heavily damaged spruce forest and to assess whether missing ectomycorrhizal fungal partners could be one of the reasons for the observed lack of regeneration. The ectomycorrhizal species richness on the roots of adult trees was significantly lower in the heavily damaged site Mumlavska hora than in the other two, but less drastically so than that found in a fruitbody survey. The roots of adult trees and seedlings were fully mycorrhizal at this site although they were less species-rich. The most abundant ectomycorrhizal species on the root system of adult trees in all three forest stands was Tylospora fibrillosa, a member of the athelioid clade. It made up over 60% of root tips in Mumlavska hora and its proportion was at least twice that in the other two sites. This species was also an efficient colonizer of roots from seedlings, in particular, in the most damaged site. The different soil properties in this site may have caused the observed differences in the ectomycorrhizal species richness and composition. For example, cation exchange capacity and soil base saturation were lower and the soil more often saturated. However, the number of living trees and their defoliation status may well directly impact the ectomycorrhizal species composition by presumably affecting the amount of carbon delivered to the symbiotic fungal partners. Athelioids and thelephoroids are an important component of the belowground ectomycorrhizal community in most temperate and boreal forests, but the role they play might even be more crucial in stressed forest ecosystems. Based on our results, we suggest that factors other than missing ectomycorrhizal inoculum constrain natural regeneration in the heavily damaged site Mumlavska hora.

Seedling mycorrhizal type and soil chemistry are related to canopy condition of Eucalyptus gomphocephala

“…In particular, detailed molecular characterization of the fungi colonizing roots is required in order to identify those ECM species that are sensitive to canopy decline of E. gomphocephala. Previous studies in other forest systems have demonstrated that defoliation might affect ECM fungi through carbon allocation to roots (Markkola et al 2004;Peter et al 2008). The situation is complex as ECM fungi may contribute to forest resilience, recovery, and vigor (Amaranthus 1998) as well as plant biodiversity and productivity in natural ecosystems (van der Heijden et al 1998;van der Heijden and van Straalen 2008).…”

“…Also, the canopy condition of E. gomphocephala in the field may impact on spore production by mycorrhizal fungi. It is generally assumed that ECM associations obtain more energy from host plants than AM associations (Smith and Read 2008) and the amount of carbon allocated below ground can influence populations of mycorrhizal fungi (Peter et al 2008). …”

“…Previous studies in Europe have identified significant changes in tree root systems, their mycorrhizal status, and mycorrhizal communities of declining trees compared to healthy trees such as in Quercus (Causin et al 1996;Montecchio et al 2004), Fagus (Power and Ashmore 1996), and Picea species (Peter et al 2008). Reduction in tree vigor might impact on mycorrhizal fungi either directly through changes in resource availability and distribution of mycorrhizas or indirectly through changes in carbon allocation to roots and changes in plant species distribution (Bellgard and Williams 2011).…”

Ecological studies of ectomycorrhizal fungi: an analysis of survey methods

“…This reduction in species was not limited to estimates based on fruiting bodies but was also confirmed using DNA identification methods on EM roottips. In a field investigation in the Czech Republic, Peter et al (2008) obtained information about the EMF community in a heavily-damaged spruce forest and assessed whether missing EMF partners could contribute to the observed lack of regeneration. The EM species richness on the roots of adult trees was significantly lower in the heavily-damaged site than in the other two sites.…”

Ectomycorrhizae associated with Castanopsis fargesii (Fagaceae) in a subtropical forest, China

“…This is because although fruit-bodies are necessarily associated with ectomycorrhizae, a fungus-forming ectomycorrhiza may not always form sporocarps, which are affected by biotic and abiotic factors in natural ecosystems (Horton and Bruns 2001). Advances in molecular techniques have allowed consistent identification of ECM fungi and have facilitated research in natural ecosystems (Peter et al 2008). Molecular studies on ECM communities have been widely carried out in temperate and boreal ecosystems (Ishida et al 2009;Wang and Guo 2010), as well as in tropical regions (Morris et al 2008;Peay et al 2010).…”