Cultivating a mycorrhizal biodiversity baseline
The socioeconomic and ecological importance of forests is widely recognised. Maintaining forest biodiversity is critical to conserving ecosystem services. Fungi play an acknowledged but not well-understood role in perpetuating forest ecosystem health, and an EU-funded consortium aimed to learn more.The ambitious project 'Mycorrhizas and Europe's oaks: A functional biodiversity knowledge gap' (MYCOIND) spanned nine countries. MYCOIND set out to establish a dataset that would enable future studies to incorporate mycorrhizal fungi when measuring forest health and biodiversity. Researchers collected live mycorrhizal fungal samples from oak forest soils in 22 study plots, and identified the samples to species-level when possible. DNA sequencing focused on the ITS region of the nrDNA, standard for fungi barcoding. The scientists then compared mycorrhizal biodiversity with forest health in each plot. Plot health ranged from pristine forests to forests heavily impacted by human activities.Two fungi — milkcaps (Lactarius spp.) and brittlegills (Russula spp.) — appear to dominate in oak forest soils. A third, ascomycote (Cenococcum geophilium) was most widespread, occurring in 21 of the 22 plots. MYCOIND identified a total of 394 fungi from 28 families, and the biodiversity of individual plots varied widely. Environmental factors had direct and indirect impacts on mycorrhizal species' richness. In particular, the presence, absence and abundance of certain fungal species are clearly tied to nitrogen availability in soils.The significance of mycorrhizal–forest interactions is difficult to overstate. Nearly all boreal and temperate forests on Earth have mycorrhizal fungi growing in their roots. Mycorrhizi play a key role in trees' nutrient and water acquisition, and one gramme of forest soil can contain hundreds of metres of these fungi. For Europe's oak forests, the MYCOIND data now offer a baseline against which future forest fungi changes can be measured by the network of researchers established during the project. Such knowledge may prove invaluable as humans seek to mitigate the threats that forests face from anthropocentric activities.
