The burning question about fungi: what happens to them in extreme heat?

Toby Kiers, an evolutionary biologist, says: ‘If we don’t understand what is going on underground … we’re just missing such a huge part of the picture.’ Photograph: Seth Carnill

When Toby Kiers and a group of fungi experts hiked the Apennine mountains in northern Italy last July, the country was experiencing its worst drought for 70 years. But Kiers, an evolutionary biologist at Vrije Universiteit Amsterdam, saw the dried vegetation and burnt forests of the drought- and fire-stricken areas bordering Tuscany and Emilia-Romagna as a unique learning opportunity.

Armed with rubber mallets, measuring tape and GPS devices, Kiers and her team were investigating a very particular life form: the bustling fungal life beneath their feet.