Described as ‘small but delightful’ by the British Lichen Society, Cladonia peziziformis, known by it’s common name the Fire Lichen, is a tiny, ground-dwelling lichen, found on just a handful of heathland habitats in South and West Britain. An increasingly rare lichen, it is classed as Critically Endangered in Britain and Near Threatened in Wales.

At less than 1cm tall, with ear-shaped green-grey scales at its base and upright fissured stalks topped with brown fruiting bodies, a hand lens is essential to get a proper look at this miniature, otherworldly species. But the real mystery of Cladonia peziziformis lies in its life cycle.

One theory is that the nutrients released by plant ash during a burn may play a role in the lichens ecology. Plant-derived smoke also contains multiple chemical compounds which may act as a germination cue, triggering its growth from a spore bank in the soil, though there has been no study to investigate this.

After its initial establishment, it’s thought that Cladonia peziziformis then starts to disappear as it is slowly outcompeted by the recovering heath vegetation.

However, in the last few years, longer-lived populations of Cladonia peziziformis have been discovered in Southern England, occurring on short, heavily grazed less acidic grasslands and heathlands, where localised burning does not always take place.

The fact that this ‘fire lichen’ can be found in habitats which don’t have fires suggests that perhaps its requirement for short open vegetation and bare soil is actually the key factor for its success.

Working alongside universities, we will also support lab trials to further investigate the impacts of fire, analysing ash, smoke, and soil nutrient content, and applying smokewater and ash to soil samples containing lichen spores to test for germination cues.

As well as providing training opportunities for students to engage with science and conservation, this research will aid our understanding of heathland fire dynamics, helping to inform future management to support Cladonia peziziformis and wider heathland management in Wales.