Final Report Summary - MYCOIND (Mycorrhizas and Europe's oaks: a functional biodiversity knowledge gap)
In boreal and temperate forests nearly all tree roots form mycorrhizas and a gram of forest soil can contain hundreds of metres of mycorrhizal fungal filaments. These intimate fungus-root mutualisms play a crucial ecological role by determining nutrient acquisition and drought tolerance of trees. Oak forests are an extensive forest type in temperate regions worldwide. In Europe, forest ecosystems are threatened due to a loss of biodiversity caused by human and environmental factors among which increasing pollution is a key threat. Ectomycorrhizal (ECM) fungi are major ecological players in these ecosystems, but they are rarely used in measures of forest biodiversity status or condition because large-scale, high-resolution, standardized and replicated data on mycorrhizal communities is lacking. Thus, we:
(1) assessed the mycorrhizal diversity of European forests creating baseline data against future forest changes;
(2) tested for relationships between mycorrhizal community composition and forest condition; and
(3) studied changes in mycorrhizal diversity and abundance across environmental gradients.
This has been carried out through field mycorrhizal sampling across nine countries (Spain, France, Belgium, the Netherlands, Germany, Britain, Hungary, Romania and Austria) in Europe at 22 intensively monitored long-term oak forest plots from the ICP Forests European network (see http://www.icp-forests.org(si apre in una nuova finestra) online for further details) mainly formed by Quercus robur and / or Quercus petraea and covering strong natural and anthropogenic environmental gradients (e.g. from 5.1 kg of nitrogen deposition / ha per year in a plot in Spain, to over 30 kg / ha per year in a plot in the Netherlands). We collected more than 6 000 mycorrhizas and had access to environmental data from the plots (soil and foliar chemistry, soil solution, atmospheric deposition, understory vegetation, tree growth, meteorology, litterfall and crown condition) through the corresponding national Focal Centre (see http://icp-forests.net/page/participating-countries(si apre in una nuova finestra) online for further details) of the ICP Forest Programme in each country. This is likely to be by far the widest and most intensive mycorrhizal survey carried out to date.
We have found that oak forests in Europe harbor a high mycorrhizal diversity, these fungal communities are formed by few dominant species and several rare ones, which makes a difficult task to capture their entire diversity. Overall we identified 394 different ECM fungi belonging to 28 families; from 24 species in a Dutch plot (0.25 - 0.3 ha) to 83 species at a Romanian plot. This reflects the high phylogenetic and functional diversity of ECM fungi and the strong environmental gradients covered. Across plots, milkcaps (Lactarius spp.) and brittlegills (Russula spp.) dominate oak ECM communities with ca. 45 % of the mycorrhizas collected, followed by the ubiquitous ascomycote Cenococcum geophilum found in 10 % of roots across twenty one out of the twenty two plots sampled. Species like the oak milkcap (Lactarius quietus; 11.5 %), Elaphomyces muricatus (false truffle), Russula vesca (the flirt) and Laccaria amethystina (the amethyst deceiver) are widespread in Europe colonizing the roots of oaks in more than 15 oak forests.
Nitrogen (N) availability (inferred from atmospheric N deposition, soil solution nitrate and N content in leaves) among other environmental factors seems to directly and indirectly affect (e.g. through changes in soil pH) the mycorrhizal community composition of oak forests at large spatial scales. Fungal species richness decreases with increased N atmospheric deposition while fungal communities become less even due to an increase in N tolerant species. From the big pool of ECM species found, some of them could act as belowground indicators of oak forest condition; e.g. Scleroderma citrinum (common earthball) and Lactarius quietus tend to be more abundant in high N availability conditions while Laccaria amethystina tends to be scarce in N-rich environments.
We deliver, for the first time, valuable baseline data on ECM fungi that will contribute to a better understanding of expected changes in oak forests in Europe and on the functional significance of mycorrhizal diversity and abundance in these ecosystems. Prediction of these changes would allow faster reactions to avoid degradation of ecosystem goods and services. Taking initiatives to address relevant ecological questions contributes to a mechanistic and predictive understanding of the environment. Thus, data resulting from this project will contribute to European environmental interests and competitiveness across a range of spatial and temporal scales. This project provides novel understanding of the role of fungi in oak forest ecosystems that can help to design appropriate forest conservation strategies. Moreover, the wide geographical scale in which this project has been developed has involved collaborations with twelve national forest research institutions and foresters from nine European countries creating a new network for European mycorrhizal research collaboration.
(1) assessed the mycorrhizal diversity of European forests creating baseline data against future forest changes;
(2) tested for relationships between mycorrhizal community composition and forest condition; and
(3) studied changes in mycorrhizal diversity and abundance across environmental gradients.
This has been carried out through field mycorrhizal sampling across nine countries (Spain, France, Belgium, the Netherlands, Germany, Britain, Hungary, Romania and Austria) in Europe at 22 intensively monitored long-term oak forest plots from the ICP Forests European network (see http://www.icp-forests.org(si apre in una nuova finestra) online for further details) mainly formed by Quercus robur and / or Quercus petraea and covering strong natural and anthropogenic environmental gradients (e.g. from 5.1 kg of nitrogen deposition / ha per year in a plot in Spain, to over 30 kg / ha per year in a plot in the Netherlands). We collected more than 6 000 mycorrhizas and had access to environmental data from the plots (soil and foliar chemistry, soil solution, atmospheric deposition, understory vegetation, tree growth, meteorology, litterfall and crown condition) through the corresponding national Focal Centre (see http://icp-forests.net/page/participating-countries(si apre in una nuova finestra) online for further details) of the ICP Forest Programme in each country. This is likely to be by far the widest and most intensive mycorrhizal survey carried out to date.
We have found that oak forests in Europe harbor a high mycorrhizal diversity, these fungal communities are formed by few dominant species and several rare ones, which makes a difficult task to capture their entire diversity. Overall we identified 394 different ECM fungi belonging to 28 families; from 24 species in a Dutch plot (0.25 - 0.3 ha) to 83 species at a Romanian plot. This reflects the high phylogenetic and functional diversity of ECM fungi and the strong environmental gradients covered. Across plots, milkcaps (Lactarius spp.) and brittlegills (Russula spp.) dominate oak ECM communities with ca. 45 % of the mycorrhizas collected, followed by the ubiquitous ascomycote Cenococcum geophilum found in 10 % of roots across twenty one out of the twenty two plots sampled. Species like the oak milkcap (Lactarius quietus; 11.5 %), Elaphomyces muricatus (false truffle), Russula vesca (the flirt) and Laccaria amethystina (the amethyst deceiver) are widespread in Europe colonizing the roots of oaks in more than 15 oak forests.
Nitrogen (N) availability (inferred from atmospheric N deposition, soil solution nitrate and N content in leaves) among other environmental factors seems to directly and indirectly affect (e.g. through changes in soil pH) the mycorrhizal community composition of oak forests at large spatial scales. Fungal species richness decreases with increased N atmospheric deposition while fungal communities become less even due to an increase in N tolerant species. From the big pool of ECM species found, some of them could act as belowground indicators of oak forest condition; e.g. Scleroderma citrinum (common earthball) and Lactarius quietus tend to be more abundant in high N availability conditions while Laccaria amethystina tends to be scarce in N-rich environments.
We deliver, for the first time, valuable baseline data on ECM fungi that will contribute to a better understanding of expected changes in oak forests in Europe and on the functional significance of mycorrhizal diversity and abundance in these ecosystems. Prediction of these changes would allow faster reactions to avoid degradation of ecosystem goods and services. Taking initiatives to address relevant ecological questions contributes to a mechanistic and predictive understanding of the environment. Thus, data resulting from this project will contribute to European environmental interests and competitiveness across a range of spatial and temporal scales. This project provides novel understanding of the role of fungi in oak forest ecosystems that can help to design appropriate forest conservation strategies. Moreover, the wide geographical scale in which this project has been developed has involved collaborations with twelve national forest research institutions and foresters from nine European countries creating a new network for European mycorrhizal research collaboration.