Abstract
Ectomycorrhizal (ECM) fungi are essential for the uptake of nutrients by boreal forest trees. The fungi also form a major component of the biodiversity within forests, with 1100 species recorded from Sweden. The fungi are very sensitive to changes in the soil environment and most are negatively affected by the increased levels of soil N resulting from forest fertilisation. We are slowly gaining a deeper understanding of why the fungi react so strongly to N fertilisation and the overall aim of the proposed project is to increase our knowledge of the consequences of nitrogen fertilisation to the biodiversity and functioning of ectomycorrhizal fungi with a view to minimising negative impacts. The project will help verify that the long term negative effects of fertilisation may fortunately be limited and dependent upon C allocation patterns within the trees. The potential for the fungi to acidify the soil during nitrate uptake was recently highlighted and this will be investigated. The role of mycorrhizal morphology in determining fungal response to fertilisation will also be determined. The potential effects of fertilisation upon the population structure of ECM fungi have been overlooked and this will be examined by determining the size of individual mycelia in negatively- and positively-affected fungi. The final part of the project will synthesise current knowledge and new results into a mechanistic model describing how ECM fungal communities react to forest fertilisation.
Sweden