Hunting for grassland fungi

In the northern part of Norway on the coast of Helgeland, we find Tjøtta Farm. Here are particularly good examples of semi-natural grasslands that are traditionally managed, making them ideal for exploring fungal diversity.

Large parts of this grassland have been continuously grazed by sheep and cattle since the Viking Age, without fertilisation, ploughing, or reseeding. In this landscape, a significant diversity of grassland fungi has been found. Many are rare and red-listed for endangered species.

Modern agriculture has led to the abandonment or intensification of many traditionally managed pastures. As a consequence, semi-natural pastures are becoming increasingly rare, along with the diversity of grassland fungi related to them.

The diversity can survive a few years without livestock grazing. However, when trees and shrubs take over, the rare grassland fungi are outcompeted by more common woodland mycorrhiza fungi.

The situation becomes even more critical if the pasture is fertilised. Grassland fungi are highly sensitive to nitrogen, and with fertilisation, the rich diversity will be lost, possibly for ever.

Research Scientist Thomas Holm Carlsen regularly surveys the pasture on Tjøtta. In his experience, a single field visit is not sufficient to assess the diversity of fungi in an area.

"Fungi are mainly a network of hyphae that branch out underground. On the surface we merely see the fruits. The fungi only produce fruits when conditions are right. Therefore, we are in the field several times during the season to capture the diversity of grassland fungi," he says.

"It's pretty cool that an apparently dull mushroom can turn out to be a completely unique discovery if you just take a closer look."