Killer fungus could be good news for habitats decimated by invasive moss

Killer fungus could be good news – A previously unknown species of fungus has been identified in the UK, offering a glimmer of hope for ecosystems struggling against the dominance of an invasive plant. This discovery, made by Dr. George Greiff, highlights a potential natural defense against the spread of heath-star moss, a species that has been aggressively encroaching on native habitats. While the fungus is named for its destructive power, it may act as a beneficial agent in the fight to restore balance to British environments.

Combatting an Unseen Threat

The heath-star moss, a non-native species, has been causing significant disruption to UK landscapes by outcompeting native vegetation. Greiff, a 30-year-old scientist, first noticed the moss’s damaging effects while exploring the Isle of Wight four years ago. He encountered dead patches of the plant on a cliffside and took samples, but the cause remained a mystery. Over time, he observed more instances of decaying moss, prompting further investigation.

Working alongside researchers in both the UK and France, Greiff has finally unraveled the mystery. The culprit, now known as *moss die-back*, is a previously undocumented fungus that specifically targets heath-star moss. “It’s fascinating,” he says. “We often think of fungi as harmful, but this one seems to be a welcome presence in the ecosystem.” This finding suggests that the British environment may have its own natural mechanisms to counteract invasive species.

The Spread of a Dominant Invader

Heath-star moss has become a pervasive presence across Britain, from hillsides to sand dunes and even garden fences. Greiff notes its remarkable adaptability, including its ability to grow in tarmac. “It’s a striking plant,” he admits, plucking fragments from a clump of green moss. “But its spread has led to some serious issues.” The moss’s rapid reproduction and far-reaching spore dispersal have made it a formidable invader, threatening the biodiversity of native habitats.

Non-native species have long been a challenge for the UK’s ecosystems. Around 2,000 such plants and animals have been introduced from global regions, either accidentally or intentionally. Among the most infamous are the North American grey squirrel, which has nearly eliminated native red squirrel populations, and the Japanese knotweed, notorious for damaging homes and infrastructure. Rhododendron, another invasive species, leaves toxins in the soil, further complicating ecological recovery.

Greiff’s research has shed light on the heath-star moss’s origins. Scientists believe the species arrived in the UK in the 1940s from the southern hemisphere. By the 1990s, it had spread extensively, replacing native mosses in many areas. “This moss has just exploded,” he explains, emphasizing the dramatic shift in local ecosystems. In the 1930s, native mosses would have thrived in such environments, but now they face a formidable opponent.

A Fungal Fighter in Action

Greiff’s journey to uncover the fungus’s role began with a simple observation of decaying moss. He guided BBC News to a site in south Wales, where the “fairy rings of death” caused by the fungus are visible. “It’s like seeing the aftermath of a battle,” he remarks, scanning the ground for signs of the fungus’s activity. His meticulous attention to detail is evident in the way he carefully examines the moss, noting how it has created gaps for other plants to flourish.

During a walk in the Bannau Brycheiniog national park near Abergavenny, Greiff discovered a patch of dead moss as large as his hand. “It’s a patch of death,” he says, demonstrating the fungus’s destructive work under a microscope. The camera crew, equipped with a macro lens, captured the white blobs on the moss tips, revealing the fungus in action. These microscopic invaders cling to the moss stems, expanding like cotton candy around the plant’s structure. In some cases, they even penetrate the moss cells, causing irreversible damage.

Greiff’s analysis indicates that this fungus is a close relative of the ash die-back pathogen, which has devastated up to 80 million ash trees in Britain. While this raises concerns about its potential impact on other species, his findings suggest it primarily targets heath-star moss. Only a limited number of other moss types appear to be affected, though further research is needed to confirm its full range of influence.

Hope for Ecological Recovery

Greiff’s discovery underscores the importance of native flora in maintaining ecological balance. Mosses are vital to the UK’s most valuable habitats, such as rare temperate rainforests and carbon-storing peatlands. These ecosystems rely on the presence of diverse moss species, which provide essential soil stability and support a wide array of life forms.

As a researcher, Greiff has developed a keen eye for identifying fungal activity in the wild. He jokes that the map of the fungus’s presence also marks his holiday destinations, reflecting its widespread distribution. “The process of identifying this fungus required a lot of DNA sequencing,” he explains, showing the microscopic evidence of its work. This effort has not only clarified the fungus’s role but also highlighted the need for continued monitoring of invasive species and their natural predators.

While the heath-star moss remains a significant threat, Greiff believes the newly discovered fungus could be a native species that has evolved to combat it. This theory suggests a rare instance of the British environment launching a counterattack against its own invasive invaders. The implications of this finding are profound, offering a potential solution to the ongoing battle between native and non-native species in UK ecosystems.

Greiff’s work has already demonstrated the fungus’s ability to create space for native plants like heather to take root. “It’s a natural process,” he says, pointing to these regrowth areas. “The fungus isn’t just killing the moss—it’s opening the door for other species to thrive.” This dynamic interaction between invasive plants and their fungal adversaries may provide a model for future conservation strategies.

As the UK continues to grapple with the challenges of invasive species, Greiff’s discovery serves as a reminder of the resilience within nature. The moss die-back fungus may not be a silver bullet, but it represents a critical step toward restoring the delicate balance of ecosystems. With further study, this newfound ally could help protect the UK’s rich botanical heritage and preserve its native habitats for future generations.