The moist soundscape of a healthy bog – the gurgles, squelches and burbles – is best heard on your knees, with your ears tilted close to the ground. It’s not an easy position to hold, given a functioning bog has the consistency of wobbly jelly; the top half-metre is a spongy carpet of sphagnum vegetation, which floats on water. Yet somehow, like a bowl of jelly, the bog manages to keep its shape and form.
One of the last remaining raised bogs in the east of Ireland is Raheenmore in Co Offaly, a few miles northeast of Tullamore. At just over 15m deep – five metres deeper than most other bogs – it’s one of the deepest in the country. Unlike many bogs in the area, Raheenmore was not drained for agriculture or cut for commercial peat production. For the past 40 years it has been managed as a nature reserve, and it’s legally protected by Irish and European law as a Natura 2000 habitat, one of 604 such sites across the country.
If you look at Raheenmore from above, it’s a 210-hectare patch of soggy, boggy brown – a 10,000-year-old remnant of the landscape – surrounded by a patchwork of green fields. Although dry at the margins from historical cutting, it is primarily a watery, tranquil paradise still bulging with life.
Within minutes we came across a patch of gloopy, decaying sphagnum. Dr Kelleghan called it a sign of ammonia pollution
The plump carpets of bright green and crimson sphagnum mosses are the glory of this bog, so delicate and exquisite to the eye, yet dominant and specific in their requirements as plants. Sphagnums need waterlogged, acidic conditions to survive, and that’s the environment they create. They have cells that, like microscopic reservoirs, can retain up to 20 times their dry weight in water. If there’s a downpour of rain, every last drop is soaked up.
Sphagnum mosses don’t like competition; to limit other plants, they acidify their surroundings, changing it to a pH similar to that found in a glass of grapefruit juice. This creates ideal conditions for the retention of water while inhibiting bacterial and fungal growth. A waterlogged, acidic habitat is perfect for accumulating partially decomposed plant material. And given lots of rain and a bit of time, sphagnum is the ultimate bog-builder.
A few years ago I visited Raheenmore with Dr David Kelleghan, an Irish air pollution scientist specialising in the ecological impacts of ammonia, a form of nitrogen. We stepped into it and soon felt the squelchy, bouncy bog under our feet. I spotted ruddy insect-eating sundew plants, and the spider webs were so numerous it seemed as if they were weaving a giant-sized web across the surface of the entire bog. With so much water underfoot, each step is carefully placed, mindful that at any moment your feet can be suddenly sucked into the sodden ground.
[ Sustainable agriculture plan based on bog restoration begins in OffalyOpens in new window ]
Within minutes we came across a patch of gloopy, decaying sphagnum. Kelleghan, who had been monitoring ammonia levels on Raheenmore for about a year, called it a sign of ammonia pollution. We knelt down to get a closer look. Ammonia is alkaline and disrupts the sphagnum’s environment, leading to cellular collapse and death. Ammonia also promotes the growth of nitrogen-loving plants. Sphagnum doesn’t stand a chance in the face of rising ammonia levels.
In 2016 Ireland exceeded its legally binding ammonia limits for the first time. Nearly all ammonia pollution comes from intensive livestock farming. According to the Environmental Protection Agency, the rapid expansion of the dairy sector is one of the main reasons we have about 10 times more of it in our atmosphere than would naturally occur.
However limited, the damage to Raheenmore from ammonia pollution is a warning sign of what might be ahead unless decisive action is taken to cut ammonia. As I stood on the bog with Kelleghan, I was reminded of Ballynahone bog at the tip of Lough Neagh in Northern Ireland, which has become, in parts, so denuded by ammonia that the ground is dry and crispy.
Steps have been taken by the EPA and the National Parks & Wildlife Service to set up, for the first time, permanent ammonia monitoring on some of Ireland’s legally protected sites, such as Raheenmore. If the State were serious about protecting habitats and establishing a truly sustainable food system, it would have implemented this years ago – after all, you cannot manage what you don’t measure. It’s a welcome step nonetheless.
And so, once a month, small plastic tubes containing filter paper, soaked in citric acid, are placed in a small number of protected habitats across the country. The acid absorbs ammonia, and it’s from these samples that scientists estimate how much ammonia is in the air and assess the potential damage.
In Ireland we have 60 per cent of Europe’s remaining active bogs. Public money is being poured into their restoration, but their future is perilous
Scientists say the source of ammonia in Raheenmore is from nearby cattle farming and slurry spreading. The EPA regulates pig and poultry farms for ammonia but not dairy, even though most emissions come from cattle. Where slurry is spread, scientists say, nearby habitats have high concentrations of ammonia, with potentially lethal results.
Each year, the 40 million tonnes of slurry spread on land should be regulated and accounted for under the nitrates directive. But speaking recently to Clare Byrne on RTÉ Radio 1, Teagasc specialist Eddie Burgess voiced what has been whispered for years: this system, which is supposed to be overseen by the Department of Agriculture and the Department of Housing, isn’t working, and fraudulent, bogus movements are taking place. It’s an abysmal regulatory failure by the State, causing untold damage to our habitats and waterways. It is also deeply unfair to the many farmers who have abided by the regulations.
In Ireland we have 60 per cent of Europe’s remaining active bogs. Public money is being poured into their restoration, but their future is perilous without ammonia emissions being urgently slashed.
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