Distinctive lichen disappears from Welsh mountains

One of the most unusual and distinctive lichens to have grown on the mountains of north Wales is now considered to be extinct following a recent survey.

Natural Resources Wales (NRW) commissioned a survey of the four Welsh mountains where the Whiteworm Lichen (Thamnolia vermicularis) was known to inhabit, but no signs of the species were found.

Sam Bosanquet, Specialist Advisor: Non-Vascular Plants at NRW, said: “The Whiteworm Lichen is found in mountainous areas worldwide, and grows as distinctive worm-like, hollow tubes on exposed mountain tops. It relies on a symbiotic relationship between a fungus and an alga to thrive in habitats where the fungus alone couldn’t survive.

“Despite 136 clumps being recorded on Cadair Idris between 2000 and 2003, a 2019 survey failed to find any examples on the mountain. A further survey in 2022 confirmed that there were no colonies left on Cadair Idris, nor elsewhere in Eryri, which has led us to conclude that is now extinct in Wales.

“The disappearance of Whiteworm Lichen in just 20 years raises concerns about the future of other mountain plants and fungi in Eryri”

Climate change 

Climate change poses a significant threat to mountain species. But lichens and plants face an additional challenge from nitrogen pollution generated by intensive agriculture and industry, which is transported through the atmosphere and deposited on uplands.

The nitrogen acts as a fertilizer, promoting the growth of certain plants and crowding out the area where the Whiteworm Lichen used to thrive.

Pollution modelling reveals that UK agriculture’s ammonia emissions contributes over a third of the nitrogen pollution affecting Eryri.

Mr Bosanquet added: “Extinction is not just a threat for the future: it is happening all around us.

“While it’s too late to save the Whiteworm Lichen in Wales, we can still take action to protect other mountain species facing the combined effects of nitrogen pollution and climate change.

The Natur am Byth! partnership led by NRW, provides an opportunity to tackle this threat, with over £4.1 million awarded to the partnership by the National Lottery

One of the projects supported by the funding – The Tlysau Mynydd Eryri / Eryri’s Mountain Jewels project, led by Plantlife – aims to safeguard some of the most vulnerable plants and invertebrates found on the slopes of Welsh mountains.

By bolstering populations, removing additional threats such as inappropriate grazing, and educating people about these rare plants, the project plans to help these species to be more resilient to climate change.

Additionally, the Welsh Government intends to incorporate measures to reduce ammonia pollution in the Sustainable Farm Scheme, which could contribute to lowering nitrogen pollution levels and prevent further losses.