New "Killer Fungus" Offers Hope for UK Habitats Ravaged by Invasive Moss

The discovery of a previously unknown fungal species in Britain that targets a highly aggressive invasive plant has sparked optimism regarding the restoration of native ecosystems that have been severely degraded. This fungus specifically infects heath-star moss, a non-native species that has been encroaching upon and displacing indigenous flora across the UK. Researchers suggest this biological interaction may mark a significant ecological counterattack by the British environment against invasive species.

Dr. George Greiff, a 30-year-old scientist, led the investigation into the moss die-back fungus, guiding BBC News through its effects in south Wales. Greiff initially identified the phenomenon four years ago while hiking on the Isle of Wight. Upon noticing dead patches of invasive moss on a cliffside, he collected samples but could not immediately determine the cause of the decay. However, as he observed more instances of decaying moss, he collaborated with colleagues in the UK and France to solve the mystery. The result was the identification of a potent, unprecedented fungus, now classified as the moss die-back agent.

While fungi are often viewed negatively, this particular strain is considered beneficial. Its target, heath-star moss, is ubiquitous throughout Britain, appearing on hillsides, sand dunes, and even garden fences. "It's aggressive. I've even seen it growing in tarmac," Greiff noted. He acknowledges the moss’s aesthetic appeal, plucking fragments from a green carpet to illustrate its appearance, but emphasizes the ecological damage it causes.

Since humans introduced approximately 2,000 non-native plants and animals to Britain, either accidentally or intentionally, some have come to dominate local ecosystems. The North American grey squirrel, which has nearly eradicated native red squirrel populations, is a well-known example. Among plants, Japanese knotweed, known for damaging structures, and rhododendron, which leaves toxic residues in soil, are major offenders. However, less is understood about heath-star moss. Scientists believe it arrived from the southern hemisphere in the 1940s and had spread to nearly every location in the UK by 1990.

"This moss has just exploded. In the 1930s, native mosses would have been growing here instead," Greiff explained. The UK is home to over 1,000 moss species, which serve as the foundation for critical habitats such as peatlands and rare temperate rainforests (damp coastal woodlands). These ecosystems are vital for carbon storage but are currently under threat from non-native flora. Heath-star moss spreads rapidly via widespread spore dispersal, making it a highly successful invader.

Greiff, who works at Amgueddfa Cymru museum in Cardiff, recalled his initial ignorance of the moss, admitting he once threw a sample in the bin. He is now scanning landscapes for signs of the fungus’s activity. During a walk through Bannau Brycheiniog national park near Abergavenny, south Wales, Greiff pointed out areas where native moss populations have significantly declined or gone locally extinct. His keen observational skills allowed him to spot "patches of death" on low banks.

Soon, Greiff located a ring of dead moss roughly the size of his hand. While the scene appeared understated to the naked eye, a macro lens revealed white fungal structures suspended on the moss tips. Greiff highlighted nearby baby heather plants, which are now able to establish themselves in the gaps created by the decaying moss. With his awareness of the fungus’s benefits, Greiff now seeks it out wherever he travels, joking that his travel map mirrors the locations where the fungus has been found.

Full identification required extensive DNA sequencing. In a laboratory at Amgueddfa Cymru, Greiff demonstrated the fungus under a microscope, showing how it attaches to moss stems, expanding like cotton candy around a stick, and even penetrating moss cells.

Source: BBC News Generated at: 2026-05-30 23:03:12 UTC