Tipperary County Council spent nearly €250,000 tackling invasive species over the last four years.
However biodiversity experts say preventing the spread of invasive species now will stop us spending huge amounts on them in the future.
The Journal Investigates found councils across the country spent over €8.5 million to deal with non-native plants and animals between 2020 and 2024.
The costs incurred by Mayo County Council over that period was almost €1.3 million
Japanese knotweed, sika deer and rhododendrons not only affect their environments but can be dangerous to humans.
Report author Anthea Lacchia says a wide scope is needed to stop the damage.
“Really we need to be considering the whole of Ireland – and not just Ireland – but adjacent countries in terms of how we manage these species. So we need to respond very rapidly because once they actually take hold and spread they’re very, very difficult to remove and very costly to remove. So the key really is prevention.”
