The lecturer with the School of Biological Sciences at Queen’s University and a former senior scientist with Inland Fisheries Ireland (IFI), warns the problem is growing but the public is largely unaware of it. “While I was in IFI, I headed up an invasive species section. It was meant to be only a relatively small section of my work but it ended up being a full-time commitment,” says Prof Caffrey, who has devoted over 20 years of his career to working on invasive species.

He defines invasive species as non-native plant or animal species that are harmful, either to the economy, to human health or to the environment. A study by the National Biodiversity Data Centre identified around 340 potentially damaging species in marine, terrestrial and freshwater habitats. Further studies identify 60 ‘High Impact’ invasive species that have the potential to cause significant damage. “Realistically, we’re talking about 60 or so species but there is very little awareness about them,” he says. “One of the big questions we have is how do we get this information across to the person on the ground, who, inadvertently, is the one spreading them.”

“Work on this plant should always be overseen by a competent professional. You need to draw up a management plan because it’s going to take two or three or even four years,” he said. Generally, the favoured route of treatment is to inject the stems with herbicide, a process that can take up to four years before the plant is eradicated. Legally, landowners are obliged to excavate knotweed and have it removed to a landfill.

Prof Caffrey believes farmers have a huge role to play in its control and this can be achieved by implementing biosecurity measures like cleaning and disinfecting to prevent the spread. “I know farmers are very careful about pests and diseases and I would urge them to be equally conscious of the problem that is invasive species,” he says. “Even things like cleaning their boots or tractors, having worked in a certain area, is something that needs to be done and should be mandatory. “That’s the way forward and the only way we’re going to stop introducing and spreading invasive species.” He would like to see awareness about invasive species included in the curriculum at primary school level to educate people on how damaging invasive species actually are.