Another Life: Why we need even more wetlands

Whatever sun there is glints on shards of mirror in the shore’s sandy grassland. We are lucky to live on a hillside, looking down on silvery, wind-shimmered ponds of rain, and not watching the last of the midland floods oozing back into the Shannon.

February 2nd was World Wetlands Day, as if that was something to celebrate. To mark it a new map of the wetlands of Co Roscommon was launched. It is the latest in a national survey of wetlands, so far totting up 9,881 throughout Ireland.

Roscommon may have thought it had a mere 74, but Wetland Surveys Ireland, expert consultants in these things, found another 568 throughout the county, Indeed, if you look at their revised national map, little flags for each site are crowded across the Republic. There'll be even more when they've updated Offaly, Galway and Donegal in work scheduled for this year.

But what, exactly, makes a “wetland” and why should we need to keep them all? In their enormous variety, from bogs, fens and drainage ditches to turloughs, estuaries and shore lagoons, they offer some 25 distinct Irish habitats dominated by water and with specially adapted plants, animals and insects.

Interest in conserving wetlands in Ireland has concentrated greatly on birds, notably the great flocks of swans, geese and ducks that migrate here in winter. But maintaining biodiversity is the prime aim of conservation, so the myriad of underwater lives should matter even more. Fish, frogs and newts, yes, but also freshwater mussels, water beetles large and small, and the larvae of dragonflies, mayflies, caddis flies and even, dammit, midges.

But decisions about what to define as wetland can still be unexpected. Clicking among the thicket of flags on my local corner of the national wetland map, I raised a habitat on the Mayo shore of Killary Harbour, beneath the steep slope of Mweelrea Mountain.

There, at the tumbled ruins of Derry, a tiny pre-Famine clachan far from any road, grow tall thickets of bushy Mediterranean heather, just coming into bloom. They flourish on the banks of little streams running down from the mountain.

Their choice of streamsides and lakeshores has made this rare and lovely heather, introduced to Ireland centuries ago, a particular treasure for Mayo, and their home on the Killary is now part of the "Lost Valley", a new tourist stop on the Wild Atlantic Way.

Without the wild plants of our wetlands much of Ireland would be dominated by farming’s dull grasses. When wetlands ceased to be important for food, fuel, thatch and clay, the hunger for more dry farmland saw them as wasteland. All over Ireland thousands of the shallower ones were drained.

Even now their role in holding back rainfall, absorbing polluting sediments, and helping flood control often fails to register.

With the winter’s misery still raw, this may not seem the time to preach about constructed wetlands – the deliberate creation of new ones. Many, indeed, would be a restoration of lost hollows, ditches and streams in farmland, with a wealth of new expertise to get them flowing effectively again. The technical term “wetland reanimation” carries the right sense of restoring life to the earth, of re-creating one of its generous ecosystem services.

At its most ambitious an integrated constructed wetland – an ICW in the jargon – can deal with the sewage of a whole community. Its low-tech construction can save substantial money over conventional sewerage works of concrete pipes and tanks. Such an ICW absorbs virtually all the polluting nitrates and phosphates and creates a pleasant, planted local landscape with a rich variety of wildlife.

A showpiece ICW in Ireland has been one at Glaslough in Co Monaghan, created on the Castle Leslie demesne. A network of five planted ponds deals with the waste from a village, a hotel, a restaurant and an equestrian centre, all with about 800 people. Its success is drawing close interest from planners with Irish Water.

Indeed, Ireland’s development of ICWs over the past three decades has brought wide EU involvement, along with government guidelines for wetlands on sloping land of farms in Ireland and Scotland.

The model for these was pioneered by Dr Rory Harrington, a former senior ecologist with the National Parks and Wildlife Service. Under his guidance a group of farmers at Anne Valley, Co Waterford, constructed a sloping wetland that filters farmyard waste through vegetated and landscaped ponds to deliver clean water, fit for brown trout, to the adjoining Annestown river.

As climate changes, delivering both drought and floods, wetlands will be a great moderator, whether holding back the flow of too much rain or as reservoirs when no rain falls. Building more to absorb the waste of rural communities, or to deal with farming’s mucky water, is both to borrow the planet’s natural processes and offer new homes for its wildlife.

Michael Viney's Reflections on Another Life, a selection of columns from the past four decades, is available from irishtimes.com/ irishtimesbooks