Investigates Soil InvadersINVASIVE SPECIES MANAGEMENT cost councils an average of €1.7 million a year in recent years, The Journal Investigates can reveal.
Over €8.5 million was spent across all councils from July 2020 to August 2024.
This is “a drop in the ocean” compared to what would be required to seriously turn the problem around, says Eoghan Daltun, a farmer, rewilder and author of two books on Irish rainforests.
“That won’t stop the problem from getting worse by a long shot,” he told The Journal Investigates.
Invasive species have devastating consequences on the environment, displacing and replacing native species and damaging ecosystems. Today we reveal for the first time just how much local authorities are spending to tackle the issue.
The top three spending councils over those four years were Mayo, Cork and Meath County Councils, with total spends of approximately €1.28m, €950k and €814k, respectively.
Next up were Galway and Fingal County Councils, with spends of around €700k
and €650k each.
For 11 of the councils, the amount spent increased from 2021 to 2023, while for 10 councils it stayed roughly the same.
These figures were obtained through Access to Information on the Environment (AIE) requests for our SOIL INVADERS investigation, a multi-part series out over the coming week, into the spread of invasive plants in Ireland.
The local authority spend, which includes prevention, eradication and control of the invasive species, is likely to be an underestimate, as it does not include the end of 2024 and start of 2020, as well as activities hindered by the Covid pandemic.
In addition, Kerry and Westmeath County Councils and Dublin City Council told us that they did not have any information on amounts spent on invasive species management. A number of other councils only provided partial information.
Invasive species are species that are not native to Ireland and cause harm to the environment, human and animal health, and the economy.
Giant hogweed’s sap can cause severe burns and scarring, rhododendron engulfs native forests making it impossible for native plant saplings to grow, and Japanese knotweed’s ability to grow through concrete makes it a “disaster” for property.
They can be introduced either intentionally or accidentally, and include plants as well as animals such as sika deer, American mink and zebra mussels.
Most of the money spent by local authorities was directed towards controlling the spread of Japanese, Himalayan and Giant knotweed through multi-annual spraying of the plants with herbicide by council-appointed contractors.
Other common species treated and removed by councils included Giant-rhubarb, Giant hogweed, rhododendron and cherry laurel.
Removal of invasive species from contaminated soils in preparation for housing developments was another key reason for the spend.
When asked for the reason for the high spend, a spokesperson for Mayo County Council told The Journal Investigates that “this is largely due to the specialist removal of many invasive species… and associated contaminated soils from various sites in preparation for Social Housing Developments”.
Hans Visser, biodiversity officer at Fingal County Council told us that “all funding for invasive species in Fingal is spent on eradication measures of Japanese knotweed, Himalayan balsam, Giant hogweed, sea buckthorn, cherry laurel, rhododendron and mink”.
A spokesperson for Cork County Council said that “the expenditure was used for the survey and treatment of various invasive species, primarily Knotweed, but also Gunnera and Winter Heliotrope, on council property in multiple locations across the county”.
“The level of expenditure reflects the scale of the county (Cork County Council is the largest local authority by area) and the nature of treatment required.”
Despite millions being spent each year, invasive species are still proliferating in many parts of the country, our investigation has found.
In West Cork’s Beara Peninsula, there are “huge problems with invasive species”, said rewilder and author Eoghan Daltun.
The three most problematic species in this part of Ireland are Rhododendron ponticum, sika deer and feral goats, he said, explaining that a mild, wet temperate climate is creating the perfect conditions for them to spread.
I don’t think there is an awareness of what a threat invasive species are to what nature we have left.
“If we zoom out, invasive species are the second biggest driver of biodiversity loss on the planet,” he said.
When it comes to plants, in Ireland there are more non-native species than native ones, according to the latest plant records by the Botanical Society of Britain and Ireland (BSBI).
In its latest Plant Atlas, the BSBI reported a “devastating” loss of Irish flora. Out of 1,939 plant species recorded in Ireland, only 952 were native and 987 were not native.
The estimated annual global cost of invasive species is a staggering $423bn. On the island of Ireland alone, it was estimated over 10 years ago that they cost the economy €261m a year.
“Invasive alien species are a major and growing threat to biodiversity and ecosystems, but also to people globally,” said Professor Helen Roy, an ecologist who specialises in invasive species and is based at the UK Centre for Ecology & Hydrology and the University of Exeter.
Commenting on the amounts spent by local authorities in Ireland, she said: “The cost would be far greater if there wasn’t that action now. Things would be a lot worse if those things were not being done and that money was not being spent.
“60% of global extinctions are caused either solely or by invasive alien species working alongside some other kind of driver, which I think is a staggering figure,” she said.
“Although invasive alien species are one of the main drivers of biodiversity loss, actually managing them is achievable, but it is urgent. We need to be acting now in order to be able to meet the benefits of that action,” she told The Journal Investigates.
Quicker action is needed, according to Eoghan Daltun.
“The big problem with invasive species is that generally, across the board, not just in Ireland, action tends to only begin to be taken when they’ve already spiraled out of control,” he said.
This is “the wrong way to be approaching these things, because that’s when it becomes massively difficult to tackle the problem”.
We really need to be far more on the ball in getting in there quickly when the problem is still manageable, and nipping it in the bud.
Ireland’s 4th National Biodiversity Action Plan aims to control, manage and where possible, eradicate invasive alien species by 2030, as well as adopting an all-island approach by 2025.
The National Parks and Wildlife Service (NPWS) is leading the implementation of the National Biodiversity Action Plan as well as being responsible for legislation and policy around invasive alien species in Ireland.
A spokesperson for the NPWS told The Journal Investigates that “much of the work in tackling invasive alien species happens at local level and is carried out by local authorities in their areas through their own biodiversity action plans”.
“NPWS supports this work through initiatives such as the Local Authority Biodiversity Action Fund.” This supports work to raise awareness of invasive species and prevent further spread.
They added that the NPWS has provided over €1.8m to local authorities in the last five years to carry out projects related to invasive species.
Despite the urgency to tackle this issue, not all money allocated to control invasive species is being spent.
Our investigation found that councils received nearly €5m in funding over the last four years. Most of this came from Transport Infrastructure Ireland (TII) and the Department of Housing, Local Government and Heritage through grants such as the Local Biodiversity Action Fund.
Most councils spent more than the funding received, and used the their own internal funds to make up the difference.
But in the case of TII funding, local authorities are not claiming the full amount allocated for management of invasive species on national roads (those with an N or M name).
Over €1.2m was not claimed between 2020 and 2024. TII increased the annual funding to councils from €450k to €800k across that time.
The amount claimed by local authorities depends on the need to manage invasive species on national roads in their areas.
“These overall annual allocations assigned for the management of IAPS [invasive alien plants] are based, among other things, on the funding available to TII annually, the many competing demands for these limited resources, and estimates of the allocation requirements of local authorities,” TII told The Journal Investigates.
“Within any year it is expected that a local authority’s claims should be below the overall allocation assigned to it.”
Amounts not claimed by local authorities annually “are redistributed to other TII funded programmes, when and as required, to maximise their delivery”, the spokesperson said.
There is clearly more that can be done to tackle invasive species, but experts told us that there is work being done on a national level to help coordinate this effort.
A dedicated Invasive Species Unit was formed last year, fulfilling a key target to improve the management of invasive species in the latest Biodiversity Action Plan.
The unit is part of the National Biodiversity Data Centre (NBDC), which for many years was gathering data and information on invasive species in Ireland and allowing people to report sightings of invasive species.
A new five-year Shared Ireland Biosecurity and Invasive Species Initiative, led by the NBDC, will also support actions in both jurisdictions, a spokesperson for the NPWS told us.
Its aim is to prevent the introduction and spread of invasive species as well as “to strengthen data collection and early detection systems”.
The NPWS partnered with the Northern Ireland Environmental Agency (NIEA) for the initiative. It involves “an investment of over €1.3 million from the Government of Ireland’s Shared Island Initiative, NPWS and the NIEA”, the spokesperson said.
“We know a lot of action on invasives is being taken by councils, tidy towns, community groups, state agencies, NGOs,” Colette O’Flynn, invasive species officer at the NBDC, told The Journal Investigates.
“There’s an awful lot happening, but from a centralised point of view, we don’t have a good overview of all the action that is being taken on invasive species.”
To help with this, the new unit recently launched an open portal called Actions on Invasives where “people can upload what they’re doing, including prevention, control, survey, awareness and research measures”, she said.
“We hope to get an overview and a better understanding of actions on invasives across Ireland.”
This is the first part of our SOIL INVADERS series on the impact of invasive plants across Ireland. Keep up-to-date with the series by signing up to our newsletter.
Reporter: Anthea Lacchia • Editor: Maria Delaney • Main Image Design: Lorcan O’Reilly • Social Media: Sadbh Cox
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