Another Life: The summer downpours send gushes of peaty water bouncing down the hill; the sun divines beautiful coppery tints as it swirls around my wellies at the ford or in the channel through the strand. The land behind the shore brims with water; there's a reed-marsh, a salt-marsh, a bog-marsh laced with lilies. Behind the duach, the big lagoon of Corragaun mingles floods from the mountain with sandy spring tides surging up the channel, writes Michael Viney.
These are all different "wetlands", each with its own mix of plants and animals, its own distinct ecology and chemistry. Sulphur from the sea reacts with hydrogen to give the salt-marsh its reek of rotten eggs; its plants swell up in succulence to dilute their burden of salt, or even drop their leaves to get rid of it. A new book, edited by UCD botanist Marinus Otte, is packed with things I didn't know.
Bogs, turloughs, callows, fens, wetland woods - each ecosystem has its experts, some of whom write more appealingly than others. One picks one's way through Wetlands of Ireland (UCD Press), leaving the stickier academic bits for subsequent solemn attention: at €60 hardback, €30 paperback, this is for people who want to learn.
Dr Otte himself, however, is among the more lucidly passionate fans of Irish wetlands. The sight of a flourishing thicket of reeds bowed by a storm almost at the edge of a cliff on Aran brought home to him their special richness and diversity. No one book had brought all the wetlands together, or made the case for their conservation. Distribution, Ecology, Uses and Economic Value is the sub-title, leaving little room to wonder what wetlands are "good for".
Ecologically, of course, they have value in their own right, as some of the most productive ecosystems in the world. Some freshwater tidal marshes, for example, produce more biomass per square metre than tropical rain forests. They offer food and shelter to many birds - the winter waders of Dublin Bay, for example, and the waterfowl and corncrakes of the Shannon callows - and to fish, invertebrates and otters.
In the cities, wetlands beside rivers and estuaries are often the only safe migration routes for wildlife; their gleaming ooze provides free passage from one habitat to another.
For value in the economic sense, we have to consider much more than peat briquettes and gardeners' peatmoss from the bogs. Just as salt-marshes buffer the ocean's assault on soft coastlines, inland wetlands are "hydrologic moderators", buffering the impact both of floods and droughts.
John Cross and Daniel Kelly write of the value of wetland woods in slowing down the rush of rain into flood-plains and filtering it of polluting phosphorus and nitrogen running off the farmland. Bankside trees give shade to salmon and trout and feed them with insects; fisheries boards welcome the promise of new riparian woodlands.
Wetlands have been receiving, using and filtering the liquid waste from people and their farm animals for thousands of years, but only in the past 40 has there been development of "constructed wetlands" that do the same job deliberately. There was an isolated example as far back as the 1880s, when the British army set up a system at the Curragh Camp in Co Kildare, and in the 1960s the late and innovative General "Mickey Joe" Costello used it as a template for his own dairy farm in Co Sligo.
For a revelatory chapter on the subject, Marinus Otte joins with Féidhlim Harty of Co Cork, a pioneer of modern constructed systems that bring reeds, bulrushes and yellow flags to the treatment of waste water and float water lilies on terminal ponds that are clean enough for trout. There are now constructed systems in over half the counties of Ireland, and if this book did nothing more than convince every county engineer of their merit, it would be deeply worthwhile; constructed wetlands cost half as much as conventional sewage treatment, need no chemical dosing and run on sunshine.
Meanwhile, existing wetlands are disappearing at an alarming rate, as their equation with "wasteland" continues to make them a target for construction, landfill and forestry. The Rural Environmental Protection Scheme should have been more help in protecting small, local wetlands, often the farmer's first choice for conifer plantations. Their place in landscape policy, when finally we get one, and their role in managing the island's flow of water, deserve serious consideration.
"What would the world be, once bereft/ Of wet and wildness? Let them be left,/ O let them be left, wildness and wet;/ Long live the weeds and the wilderness yet." Gerard Manley Hopkins had it right.