There is something delightful, but somehow also unlikely, about seeing Highland cattle in any circumstances. Their exuberant manes of russet hair and their magnificent horns seem to belong more to misty Victorian paintings than to our hard realities, and certainly more to remote moorland than to modern farmland.

So it’s a particular surprise to find half a dozen of them in St Catherine’s Park in west Dublin, adjacent to Lucan village and its sprawling suburbs.

The surprise for some residents, however, was at first an apparently unpleasant one. They found Fingal County Council workers putting up robust fencing around a meadow in the park’s bottomlands, within the River Liffey’s flood plain. “We love walking that meadow,” one of them told Hans Visser, the council’s biodiversity officer. “We love to exercise our dogs there.”

But complaints morphed into a chorus of approval when the first batch of Highland cattle made their debut appearance. The fence debate prompted much more communication about the park between local communities and the council. This will bear fruit next spring in a new playground and planting scheme, but that’s another story.

Today the cattle seem to be a hit with everyone. “They’re gorgeous-looking,” says a passerby, “and so docile you can stroke their fringes.” The cattle will walk right up to the fence, shaggy hair falling over their eyes like a nonchalant teenager’s, and, ignoring barking dogs, wait to be petted.

Although their slim, sharp and curving horns deter overly intimate or boisterous contact, they are, ironically, among the least aggressive of all domesticated cattle.

“They are really gentle giants,” says Peter Jones, the farmer who leases the grazing in St Catherine’s. He is one of fewer than a dozen Irish farmers raising Highland cattle for beef, and he is very pleased with the results so far. Despite the fact that Highland cattle take twice as long as most commercial breeds to mature, he finds that they are much cheaper to raise. Among the hardiest cattle in these islands, they will graze on moorland when other breeds need winter shelter and copious fodder.

“You offer them a bale of hay in bad weather,” says Jones, “and they’ll say thank you very much and wander off up the mountainside again. They grazed for me in the heather right through the bad snow a couple of winters back.”

As the Jones family farm is in Glenasmole, adjacent to commonage on the Dublin Mountains, his herd’s maintenance costs are exceptionally low.

But what is some of his herd doing in St Catherine’s Park? Or in Robswall Park, in Malahide, and Racecourse Park, in Baldoyle? The answer is that they play a vital part of the grazing mix that Visser is experimenting with, in the hope of maximising species richness in Fingal’s bigger parks, and farther afield in the county as well.

The cattle’s heavy hooves poach the land, breaking up the surface and making it uneven. This creates niches for “specialist” plants, long excluded by mats of uniform grasses, to creep back into the species mix.

The Highland cattle also seem to eat anything and everything. This might seem to threaten rare plants, but in fact it controls the spread of the common, dominant species, again opening up opportunities for greater diversity. Besides, cattle graze largely by tugging up plants with their tongues, rather untidily, while sheep – also in the meadow – graze by cropping vegetation closely. “The mix of feeding behaviour creates a mosaic of microhabitats,” says Visser, “and the seeds of rare native plants, long dormant in the seed bank, get a chance to germinate again.”

He stresses the experimental nature of this kind of nature management. “Is each step achieving what we hope for?” he asks himself. “We find we often have to adapt grazing regimes to achieve particular conservation goals.”

In St Catherine’s he is particularly hopeful that green figwort, a tall plant with subtly shaded purple-brown flowers, will return to the area. Where the cattle’s trampling creates mini wetlands, he envisages the return of unusual dragonflies, as well as frogs and newts. And these latter, in turn, might lure an otter from the river from time to time.

In the bigger picture, Visser is looking at all the abandoned private land along the Liffey flood plain. Ungrazed fields generally end up dominated by brambles and nettles or, worse, by invasive aliens such as Japanese knotweed. Visser hopes to show local private landowners that low-cost grazing can be both profitable and good for biodiversity.

For Peter Jones the opportunity to showcase his cattle in an urban area is a great way to publicise his specialised beef. Highland meat is said to be especially tasty, and it has proven to be remarkably low in cholesterol.

His mother, Mary Jones, hopes that local people will soon be buying it from their farm, “restoring the link between city people and food production, farm to table”. She acknowledges wryly, however, that some people may be uneasy about eating animals they have got to know so well.

Peter Jones also has some interesting ideas about using his cattle to promote biodiversity closer to his home. He has become increasingly concerned about the state of the Wicklow uplands, and he thinks the problem is as often undergrazing as overgrazing. “The vegetation in Glenasmole is becoming denser and denser, and the heather is dominated by bracken. This leaves less space for other plants, and this means less wildlife up there, too: fewer small animals and birds. The wild deer are very selective feeders. They only eat the nice things, so they are not much help. The Highland cattle, however, eat everything, and are really opening up the landscape.”

Nature needs to be managed, he says. He recalls that the mountains used to be burned regularly and lightly, which brought new growth and vitality. But today’s increased fuel load makes the fires that happen at random much more intense, “and that damages nature more”.

“The past generations did some things right,” he says. “That’s why we’re all still here. I wonder if we’re doing the same for our children. I’m not sure we are.”

glenasmolehighlandfold@hotmail.com; fingalcoco.ie/environment/conservation- and-biodiversity/