Mycorrhizal ecology of ICP Forests biomonitoring plots
Revealing the diversity, geographic ranges and environmental drivers of mycorrhizas in European forests.
Filipa Cox and Adriano Spiccia collecting samples of mycorrhizas (Photo: W. Keilig)
Although trees dominate forest environments, creating a complex habitat that shelters many species while shading out many other plants, this dominance relies on a hidden relationship with fungi. Their thread-like filaments are intertwined among the roots of many trees, forming an intimate symbiosis that helps both organisms grow - a mutualism. Both organisms need carbon and nutrients to grow and, while trees excel at capturing and storing carbon from the air, the long thin filaments excel at extracting water and nutrients, like nitrogen and phosphorus, from the soil. The magnitude of exchange can be extremely high: all of the carbon in a fungus can be obtained directly from its partner trees, while most of the mineral nutrients in a tree come directly from partner fungi.
The diverse groups of fungi involved are called ectomycorrhizal (or ECM) fungi, after the modified fine roots, or ectomycorrhizas, where the two organisms join each other. These symbiotic relationships are remarkably common: the majority of European tree species depend on ECM fungi and there are many fungi that form these relationships. Some of these fungi are well known for their sexual fruiting bodies, for example the poisonous fly agarics and the edible truffles and penny buns. However, in general, we know worryingly little about the diversity of ECM fungi. While some fungi may grow with a wide variety of trees and other plants, others may be specialists restricted to closely related tree species. And while around 8,000 species have been described, there may be many more undiscovered. In addition, we largely ignore the geographic ranges of these fungi. Some may be widely distributed, but others may be restricted to a handful of small locations; and we know that at least some can invade in other continents and that others may be locally extinct. Most worryingly of all, we know that ECM fungi are sensitive to environmental change, particularly pollution and changes in rainfall and temperature. But we do not know how these observations translate to changes at large geographical scales.
This project fills the gap in our understanding of the wider diversity and distribution of mycorrhizal symbioses, and focusses our selection of experimental and genetic models. We are making use of one of the most extensive biomonitoring plot networks on Earth in which the effects of pollution and changes in forest soil quality have been closely monitored. Kew contributes mycorrhizal expertise and ICP Forests (www.icp-forests.org) provides access to plots and intensive long-term data. We use these plots to carry out the first precise mapping of ECM fungi across Europe’s three major forest types: beech, Scots pine and Norway spruce. At each plot we use optimised molecular ecology techniques to obtain DNA sequences from ectomycorrhizas. Once we know who and where are the dominant fungi, we use the monitored data from the plots along with environmental change projections to understand the processes that control these hidden symbioses and predict their fate in our changing world.
Project partners and collaborators
United Nations Economic Commission for Europe established the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests.
Forest Research/Forestry Commission
Johan Heinrich von Thünen-Institut
Federal Ministry of Food, Agriculture and Consumer Protection
Bayerische Landesanstalt für Wald und Forstwirtschaft
Forschungsanstalt für Waldökologie und Forstwirtschaft
Nordwestdeutschen Forstlichen Versuchsanstalt
Landesamt für Natur, Umwelt und Verbraucherschutz Nordrhein-Westfalen
Forstliche Versuchs- und Forschungsanstalt Baden-Württemberg
Office National des Forêts
Forest Research and Management Institute
Ministero delle Politiche Agricole, Alimentari e Forestali, Corpo Forestale dello Stato
Dirección General para la Biodiversidad
Research Institute for Nature and Forest
Natural Environment Research Council
Forestry Commission/Forest Research
British Mycological Society