The “Killer Fungus”: A Natural Solution to Invasive Moss?
For over 80 years, the heath star moss—often called tank moss—has been quietly colonizing the UK. Since its suspected arrival on military equipment in 1941, this resilient, invasive species has spread across the country, outcompeting native flora on delicate heathlands and sand dune ecosystems. It is a true generalist, capable of growing on everything from rotting tree stumps to tarmac.
But nature may have developed its own counter-offensive. George Greiff, a researcher at the John Innes Centre, has identified a mysterious fungus that appears to be systematically killing off this invasive intruder. This discovery, born from a chance observation on an Isle of Wight cliffside, has opened a new frontier in ecological management.
Decoding the Mycological Assassin
Identifying the fungus was no small feat. Greiff noted that the organism, which he began collecting in 2017, was notoriously tricky to pin down through appearance alone. It wasn’t until he employed advanced DNA sequencing that the culprit was revealed: a member of the Bryoscyphus genus.
This group of fungi is specialized for “moss-killing.” By penetrating the moss cells from the inside while simultaneously attacking the surface with chemical compounds and physical mycelium, the fungus effectively shuts down the plant’s biological processes. It is a sophisticated, dual-action biological mechanism that has effectively turned the tide on the heath star moss in several regions.
Did you know? The heath star moss is so hardy that it can thrive on human-made structures like thatched roofs and pavement, making it significantly harder to manage than native species that require specific soil conditions.
The Future of Biological Control
While the discovery of a “killer fungus” is exciting, scientists are proceeding with caution. The primary concern is ecological safety: could this fungus jump to native, non-problematic plant species? there is the risk of natural selection—could the invasive moss develop a mutation that makes it resistant to the fungus, potentially leading to a “super-moss” outbreak?
Research is currently shifting toward:
- Host Specificity Studies: Determining exactly how narrow the fungus’s target range is.
- Resistance Monitoring: Tracking whether the moss population is evolving to survive the infection.
- International Collaboration: Comparing samples with findings from France and the Netherlands to map the fungus’s behavior across Europe.
Proactive Stewardship
If you are a land manager or an amateur botanist, keep an eye out for patches of “dieback” on mossy surfaces. Documenting these areas can help researchers like Greiff map the spread of this natural control agent. However, do not attempt to transplant or move infected moss, as this could unintentionally spread the fungus to areas where it might have unforeseen consequences.
Frequently Asked Questions
- Is the heath star moss harmful to humans?
- No, the moss itself is not harmful to humans; it is primarily an environmental concern because it displaces native biodiversity.
- How does the fungus kill the moss?
- The fungus infects the moss cells internally and externally, using a combination of chemical enzymes and physical growth to destroy the plant’s structure.
- Can I use this fungus to clear moss from my garden?
- Not at this time. The research is currently focused on large-scale ecological impacts in heathlands and dunes, not domestic garden maintenance.
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