Rhododendron: An ecological disaster in Killarney National Park

One of Ireland's finest woodland environments is under threat from the dangerous invasive plant

The great rhododendron disaster has taken place while Killarney is in the hands of the Irish nation. The nation deserves much better – Daniel Kelly, forestry expert and emeritus fellow in botany at Trinity College Dublin

Killarney National Park was chosen as Ireland's Best Day Out by The Irish Times in 2015, reflecting its well-deserved status at home and abroad for recreation, natural beauty and its bountiful weave of plant and animal life.

So you might expect that the park’s keystone oak woodlands are under sensitive ecological management, based on the best science available. After all, they are in the hands of the National Parks and Wildlife Service (NPWS), whose self-declared primary mission is “the conservation of ecosystems to maintain and enhance flora and fauna”.

The jewels in Killarney's crown, the western woodlands, are now dying on their feet, and warnings from the group that pioneered their rescue in the 1980s have been ignored

So it may come as a shock to learn that the jewels in Killarney’s crown, the western woodlands, are now dying on their feet, and that the warnings from Groundwork, the volunteer organisation that pioneered their rescue in the 1980s, have been repeatedly ignored.


These oak woods are the nearest thing we have to the ancient forests that once blanketed this island, but infestation by rhododendron now threatens their future, two decades after they were completely cleared of the invasive plant.

NPWS persists with a rhododendron management strategy which, while it sometimes appears to be making great advances, has never been tested by the service’s own scientific staff, let alone to an external review. And an exceptional volunteer resource, which had accumulated remarkable expertise, has been lost.

This raises troubling questions about whether the park’s management structure, and by extension the NPWS, is fit for purpose, at a moment when our natural landscapes across the country are more threatened than ever.

The charges and counter charges between Groundwork and the NPWS can seem as tangled as the rhododendron thickets now engulfing so many of our woodlands, in Killarney and across the country. However, after trawling through many documents that have come to light through formal complaints to the EU (and to Unesco) about the park’s environmental management, and through interviews with several NPWS staff and their critics, some patterns begin to emerge.

Rhododendron threat: one of the plants in the formerly cleared Eamonn’s Wood, in Killarney National Park, last week. Photograph: Bill Quirke/Groundwork

The central problem is clear and is not disputed. The contention is about how it may be resolved.

The park’s oak woods are among the most diverse – and rarest – ecosystems in the country. But by the late 1970s even Killarney’s remote, and therefore supposedly pristine, western woodlands were effectively “ecological ghosts”.

That is, they were still rich in magnificent mature trees, but there was no new generation rising to take their place.

Widespread infestation by rhododendron, an exotic invasive shrub, was blocking tree regeneration, and shading out the rich and distinctive communities of native plants and animals these forests support. And where rhododendron had still not penetrated, excessive grazing by deer and sheep posed, and still poses, a severe secondary threat to natural recovery, gobbling up oak seedlings as fast as they sprang up.

Rhododendron was introduced to Killarney, especially around Muckross House, in the 19th century, and began to spread quite quickly. It swept through the wilder woodlands only after the park was gifted to the State in 1932.

This ornamental plant – appreciated for its beautiful flowers, and a very effective windbreak – also creates dense thickets, blocking light and preventing the regeneration of native oak forest plants. It is a classic example of what ecologists call “invasive alien species”. Killarney’s climate suits it exceptionally well. Free of factors that curb its population in its native Turkish and Mediterranean homeland habitats, it quickly and completely dominates very large areas if not managed well.

You might have expected much better care of such invaluable natural landscapes, until you realise that there is no legislation guiding ecological standards or best practice in our national parks.

In 1981 citizen volunteers stepped in and, remarkably, the tide of infestation was slowly swept back, one square metre at a time. Groundwork, formed by budding ecologists and environmental activists, set up workcamps that were soon attracting 100-200 volunteers annually, each working for at least a week, under skilled supervision. These were not, by all accounts, holidays for the faint-hearted.

Twice, over the last two years, I have hiked with Groundwork veterans to different woods they had cleared. Each trip took several hours, just to get in and out. The terrain is steep and often very tough. The best mountain boots fill up with water before you walk 100m. Tussocks of moor grass, hidden boulders and bog holes try to twist your ankles at every step after that.

Yet in these conditions, Groundworkers achieved something some experts had doubted was possible: the complete clearance of rhododendron from half a dozen of Killarney’s most ecologically valuable woods, about 350 hectares in all.

The National Parks Service, as the NPWS used to be known, gave its blessing to this enterprise from the outset. Indeed, the service was among Groundwork’s greatest admirers. Or so it seemed.

The rhododendron strategy in the manual was not adhered to, and nor was the park plan implemented, at least in regard to Groundwork's involvement

In 2005, a four-year plan for the park was published by the NPWS, and signed off by the minister of the day. It endorsed Groundwork’s “clearly defined strategies and extremely well co-ordinated work programme” in glowing terms, and confirmed its outcome: “a significant proportion of the formerly infested oak woods in the Park [is] being maintained free of rhododendron.”

The plan assigned major future roles to Groundwork. The NPWS also chose a prominent Groundwork leader, the ecologist Therese Higgins, to write a definitive manual on national rhododendron clearance strategy. This document remains on the service’s website to this day.

Yet in the very year the plan was published, a new administration in the park diverged sharply from previous arrangements with Groundwork. The rhododendron strategy in the manual was not adhered to, and nor was the park plan implemented, at least in regard to Groundwork’s involvement.

Groundwork leaders claim they tried to work with the new managers, despite disagreements about methodology, but they had one red line. They wanted to protect the integrity of their previous work by keeping the cleared woods clear. They had found that this could be done by checking each of these areas for seedlings, once every six to eight years, keeping ahead of the plant’s reproductive cycle.

They had developed a “systematic sweep” system, similar to open-air police searches, to do these inspections. It requires a big headcount but can be carried out quite quickly, once the basic rhododendron control has been completed. They say these checks are vital to catch the fast-growing plants when they are already big enough to find easily but, crucially, before they start flowering: a single rhododendron flower can produce 7,000 seeds.

Unless the systematic sweep system is maintained, Groundwork says, rhododendron will persistently return to cleared woods from dormant seeds, or from seeds blown or carried in from other areas, for decades after the first clearance. This restarts the cycle of infestation, making the original clearance a waste of time, effort and money.

This core Groundwork principal was clearly articulated and endorsed in the rhododendron manual published by the NPWS.

Yet the new Killarney NPWS management refused to allow Groundwork to carry out these surveys. Management said it could handle this work with its own – much less numerous – staff. As a result, Groundwork reluctantly ceased operations in 2009, rather than, as they saw it, give credibility to a strategy that they believed was guaranteed to fail.

And that might have been had three prominent Groundwork volunteers, local ecologist Bill Quirke and workcamp leaders Una and Trevor Halpin, not taken it upon themselves to continue monitoring sample patches of the woods they had cleared. Since 2013, they have produced detailed reports, with numerous geo-tagged photographs, that appear to establish that re-infestation is widespread in woods that had been rhododendron-free for up to two decades.

Groundwork took this evidence to the EU Commission, making a formal complaint in 2014 that the NPWS had allowed prime (Annex 1) habitat under its care to deteriorate, thus violating the EU’s Habitats Directive. This is a very serious allegation which, if accepted by Brussels, would trigger substantial fines on the State.

The Department of Culture, Heritage and the Gaeltacht, the parent body of the NPWS, told The Irish Times that “upon consideration of the steps that the department has put in place the EU Commission decided not to pursue these complaints”.

This statement deserves analysis. First, it implicitly concedes that something had indeed gone wrong in these woods, if “steps” needed to be “put in place” to persuade the commission not to pursue the complaint.

Second, while the commission did close the first complaint on this basis in 2016, Groundwork has brought a second complaint since, based on updated evidence of continuing reinfestation. This suggests that whatever steps were taken by the NPWS, they have not been effective.

And, contrary to what the department implies, this second complaint remains open, according to Groundwork’s records.

Perhaps we need to go back to 2005 to attempt to ascertain why the previously amicable, and highly productive, relationship between the NPWS and Groundwork abruptly broke down, and what this may tell us about the national service tasked with protecting our environment.

It’s natural to wonder whether Groundwork had overstepped some boundary, or whether something untoward had come to light that forced the NPWS to distance the park from the group. Citizen environmentalists have been known to become messianic or cultish elsewhere.

But if there is a skeleton in Groundwork’s cupboard, nobody in the NPWS has ever produced it, nor did anyone I spoke to in the service attribute any misconduct to the group.

On the contrary, the group is still spoken of by senior NPWS staff with admiration and respect, and the break-up is attributed to regrettable “differences over methodology”.

Yet Groundwork claims, and the evidence seems to support this, that their methodology was much more effective at maintaining woods free of rhododendron than subsequent strategies. And this methodology had been explicitly embraced in the NPWS’s 2005-2009 plan for the park, and in the manual the service still publishes online.

Senior NPWS management consulted by The Irish Times include the principal officer responsible for science, the divisional manager covering Killarney, and the regional ecologist responsible for the area.

None of them could offer any explanation, nor find any documentary record, to show how and why the published park plan and the strategy manual were stillborn. None of them seemed to find it remarkable that there is apparently so little connection between official NPWS policies and plans for 2005-2009, and what has happened on the ground since.

Rhododendron threat: a Groundwork volunteer at work in Killarney National Park. Photograph: Bill Quirke/Groundwork

For one key party to the dispute, what happened in 2005 is very simple.

Peter O’Toole is a long-serving NPWS conservation ranger in Killarney. He has had little formal scientific training but has a well deserved reputation for determination and hard work. He was put in overall charge of rhododendron management at the park in 2005. Groundwork members say they had had warm relationships with him prior to this point.

O’Toole defends his record and the “great clearances” he and his team are doing. “We get no credit for what we’ve done. Just one organisation harping and harping on against us, trying to scupper us … it’s sickening.”

I ask O’Toole if he did not consider it a failure, at the outset of his tenure, to have lost the services of an organisation that had, according to published NPWS documents, achieved so much.

“I wish they were still here,” he says. “But they refused to work with us. They wanted to stay in the Stone Age, but we wanted to progress things on.”

This seems an odd characterisation of the group described so positively by the 2005 park plan. Far from being primitives, Groundwork was consistently led by qualified scientists, several of whom now occupy senior positions in Irish and international conservation organisations.

A founding member of Groundwork, Ciaran O’Keefe, is now one of the four principal officers (directors) at the NPWS, with special responsibility for science, biodiversity and exotic invasive species like rhododendron. But the byzantine NPWS structure determines that O’Keefe has no active input into rhododendron policy in the park.

“The reality is that we don’t have scientists directing the management,” O’Keefe says. “What we do have is a system where we employ people who we believe are competent managers, who if they need a scientific opinion… they call for it.”

So rather than being guided by science, it appears, our national park managements treat their scientific staff on the basis of “don’t call us, we’ll call you”.

O’Toole, however, argues that he has developed his own successful methodology through trial and error. And the park management has supported him unstintingly, through greatly increased investment in contractors, and the highly publicised use of a new brand of volunteer.

These are drawn from organisations including Voluntary Service International, and the local Mountain Meitheal and Men’s Sheds. They give very generously of their time but they do not purport to have any ecological expertise. O’Toole says they do what he tells them to do.

Since 2015, O’Toole works with Tim Cahalane, a contractor, who has drawn up an ambitious clearance plan for the next five years. But my interviews with the NPWS scientific staff show that the methods O’Toole is using, and which are incorporated in this plan, have still not been subjected to scientific testing.

O’Toole and Cahalane drive me through the park to see vast tracts of mature rhododendron killed by O’Toole’s system. This involves making deep cuts in the stems and injecting the herbicide Roundup. On the face of it, the method appears to be effective, and O’Toole is proud that his method avoids most collateral damage from the herbicide, and that he has greatly reduced the concentration used in each application.

The EU office examining Groundwork's complaint comments, with some stupefaction, on the lack of field records kept at Killarney National Park

There is no gainsaying the amount of work that O’Toole has overseen, the increase in the number of hectares cleared, and the increased investment in the project by the NPWS (more than €200,000 in the last year alone. Groundwork cost the park approximately one 10th of that amount annually).

But no scientific assessment has been done on the long-term effectiveness of these clearances.

When I ask the service’s regional ecologist, Jervis Good, for records of scientific testing of rhododendron clearance methods since 2005, he sends me as samples six small filing cards. They are handwritten field notes by O’Toole on his own methods, covering five months in 2008-9.

Neither Good nor O’Keefe can produce any record of independent verification or external review of O’Toole’s methodology over 15 years. The EU office examining Groundwork’s complaint comments, with some stupefaction, on the lack of field records kept at the park.

This contrasts strikingly with the meticulous record-keeping by Groundwork.

On one drive, I point out to Cahalane that regrowth is very obvious in several “cleared” areas, with plants big enough to be easily visible at several hundred metres.

“You are always chasing your tail [in rhododendron clearance],” he says, “there is no such thing as ‘clear’. I don’t deny missing a few, there are always some you miss.”

Cahalane’s language, perhaps unintentionally, precisely echoes that used by Groundwork in its first complaint to the EU:

“Without the employment of the systematic sweep method, a Rhododendron programme will chase its tail for decades, constantly ‘fire-fighting’ but never actually ‘putting out the fire’ in any particular area of wood.”

Rhododendron flowering last week in the formerly cleared Eamonn’s Wood, in Killarney National Park. Photograph: Bill Quirke/Groundwork

Groundwork, and a number of independent and well-qualified critics, fear that the park’s approach – large-scale, publicly visible clearances but, as they see it, without effective follow-up – is worse than useless. They say it is a waste of public money, as the rhododendron is already making a comeback.

I tell O’Toole and Cahalane that I have recently visited woods that had been maintained completely clear by Groundwork for decades, and which had supposedly been checked by NPWS staff or contractors only months or weeks before my visit.

I had found numerous rhododendron deep in these woods. They had not only reached a vigorous flowering stage, but had demonstrably released countless seeds in previous years.

O’Toole is “not concerned with lightly infested peripheral areas”.

Days later, O’Keefe describes these same “peripheral areas” to me as “the best semi-natural oak woods in the country”.

O’Toole continues: “Nothing has matured, and we are going back all the time, catching up all the time. You go back next time and you won’t see them. It’s not a disaster there, not at all. Only a rhododendron canopy would be a disaster.”

Perhaps this last sentence captures, more than any other, the shift in standards from Groundwork’s approach to the current one: for Groundwork, clear meant clear. Now, anything short of full domination of once-cleared wood by rhododendron appears to be good enough.

In recent years, Groundwork has gone back to these woods, again and again. Not only do they find rhododendron still growing there, they find more of it on almost every visit.

O’Keefe and Good both tell me they accept unreservedly that Groundwork’s annual data since 2013 on the return of rhododendron to these woods is accurate. This position contrasts starkly with the official NPWS response to the Groundwork EU complaint in 2014, where it was baldly stated that “no…reasonable ecological assessment of the situation could conclude that there is a reinfestation taking place in the park”.

O’Keefe and Good both agree that it is an urgent priority in 2019 to remove the plants that the group has geo-tagged, especially where they form “clumps”. They also say they would be happy for Groundwork to return to particular sites, to compare their methods with O’Toole’s (and with other methods) over time.

Overall, they say they are committed to science-led eradication in the future. But how this can happen under current NPWS structures remains unclear. Good says: “We need to do a lot more monitoring… this is not an entirely new strategy for the park, but I think we are looking for an improved strategy, yes.”

They also concur that an external and independent scientific review of the park’s entire rhododendron strategy is now needed.

Divisional manager Philip Buckley broadly agrees. O’Toole, who does not respond to follow-up questions based on the interviews with his colleagues, also says he would welcome an external review.

The issue is not who does the work but whether the cleared areas stay clear. I can see no way forward as long as NPWS conservation work is not directed by science

Taken together, these commitments seem to point to a way forward. On behalf of Groundwork, however, Bill Quirke responds very sceptically.

“The commitments which NPWS has made to you are a rerun of the commitments they previously made to Unesco in May 2017, and/or commitments made by the NPWS directors to Groundwork in May 2014, and again in 2018. We have no evidence of any of these commitments yet having been fulfilled.”

Quirke argues that Groundwork’s methodology, which the NPWS acknowledged as highly successful over a 25-year period, needs no further testing. And given the time elapsed, neither he nor his colleagues see any revival of the group in its 2009 form as realistic.

As fellow veteran Therese Higgins, author of the neglected NPWS rhododendron manual puts it, “The issue is not who does the work, or what method is used, but whether the work gets done, and whether the cleared areas stay clear. I can see no way forward as long as NPWS conservation work is not directed by science.”

Quirke and his colleagues would, however, also welcome an external review, but only if it were truly independent, and included experts who know the Killarney woodlands well. Quirke wants something else too, though: he wants to “hold accountable” those responsible for “this public service scandal”.

Rhododendron threat: one of the plants in the formerly cleared Eamonn’s Wood, in Killarney National Park, last week. Photograph: Bill Quirke/Groundwork

But who is accountable, really?

O’Toole is unquestionably a dedicated public servant. Is he to blame if he was given great responsibilities and authority, without the scientific training they surely require? The Irish Times asked the NPWS for details of O’Toole’s scientific qualifications and training, but this information was not provided.

Arguably he does not need a scientific background, but the methods of fighting this species – and ensuring the health and future of one of Ireland’s finest forests – must be the best that science can offer, and must be monitored by scientists.

I have interviewed dozens of NPWS staff, over 15 years, and in almost every case their expertise and commitment has been exceptional. But their morale is generally very low.

This service is the whipping boy for everyone from environmental NGOs to farmers, from turf-cutters to hunters. Unlike the Environmental Protection Agency, for example, or the Arts Council, it has no statutory autonomy, and it is not allowed to articulate independent views on Government policy.

Politicians shuffle the service around from one department to another with almost every change of government. They rarely back its staff, when they come under attack for attempting to enforce a raft of complex and frequently unpopular environmental laws. On the contrary, they often undermine them for political advantage. And politicians will continue doing this as long as public opinion allows them to do so.

If An Garda was as under-resourced and under-supported as the NPWS, crime would be as rampant as environmental degradation is today. Until we as a nation care as much about damage to our public landscapes and natural heritage as we do about damage to persons or private property, it may be very hard to reform the NPWS.

And if the NPWS is incapable of preventing the return of invasive plants even in prime landscapes directly under its control, like Killarney National Park, how can we expect the service to enforce nature regulations on privately owned land? Small wonder that more than 90 per cent of our nominally protected habitats are already described, by the NPWS itself, as in “bad or inadequate condition”.

One must hope that the commitments the NPWS has made to implement an improved rhododendron strategy in Killarney will be honoured. But this issue is just one symptom of a national malaise. Until public opinion forces Government to take biodiversity and landscape health seriously, the service will be expected to struggle on.

At this moment of chronic biodiversity loss and climate crisis, we shouldn’t just be debating rhododendron in Killarney. We should be considering Liam Lysaght’s recent proposal in this newspaper. The director of the National Biodiversity Data Centre wrote that we should: “Establish a Government department for biodiversity and rural economy supported by an independent State agency for nature conservation. This is essential to advocate for biodiversity and to promote innovative ways to demonstrate its benefits to the rural economy.”

Is anybody listening?

Informative or offensive?

The NPWS and Groundwork have made a number of attempts to reach a new agreement after the impasse in 2009. Several times these negotiations, the last as recent as 2018, appeared to make good progress. But each time the NPWS failed to make further contact.

In October 2011, a meeting was arranged on site in Killarney between Groundwork representatives and the NPWS, including Pat Dawson, representing management, and conservation ranger Peter O’Toole, in charge of rhododendron eradication.

While there were robust exchanges, by all accounts, some of Groundwork’s key points appeared to be accepted. The following day, Dawson wrote to Groundwork: “I found our trip yesterday to be most informative and constructive... I recognise and acknowledge the passion and commitment of all involved in the challenge of controlling and eradicating rhodo from the park.”

The following day, however, he wrote to his NPWS colleagues that “We (all three of us – as well as our divisional manager, Philip Buckley) were most upset at comments made by one or more Groundwork representatives and directed primarily at Peter, which we found offensive and most unhelpful.”

How the same meeting could be described by the same person, within 24 hours, as “informative and constructive” and then “offensive and most unhelpful” is hard to understand. Perhaps some light is shed by another email later the same month from the senior ranger at the time, now deceased, to Dawson: “I also believe that the morale of our own staff should be our number one priority when this issue [rhododendron eradication] is being considered.”

Morale is obviously important in any organisation, but should it be a bigger priority than the successful implementation of the organisation’s key responsibilities?