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|Fig 1, Snipe|
How raised bogs developed in Ireland
12,000 years ago Ireland was covered in snow and ice.
About 10,000 years ago the ice melted as a result of the climate becoming warmer.
The water from the melted ice formed lakes in low-lying areas in the Midlands of Ireland.
Plants grew around the edges of the lakes and when they died, they sank and accumulated at the bottom of the lake.
After hundreds of years the dead plants (peat) had filled the whole lake and this is known as a fen.
Types of plants, such as Sphagnum mosses which like these wet and nutrient poor conditions, colonised the surface of the fen and as they died and accumulated, they transformed the fen into a raised bog.
|Fig 2, Greater Sundew
As a result of a dry period in Ireland's climate approx 4,500 years ago trees colonized the bogs but these later died when the climate became wetter. (This explains why we sometimes find trees (such as bog oak and dale) under many metres of peat)
Over the years as the peat accumulated the centre of the bog grows higher than the surrounding mineral soil - like a dome, and for this reason these bogs became known as a raised bogs.
Raised bogs are fed only by rain water, the sphagnum mosses, which are the peat forming mosses, retain large volumes of water and have water levels generally higher than the local water table They are very acidic and poor in nutrients. The plants and animal that live on our raised bogs are especially adapted to these conditions. Raised bogs consist of domed masses peat which can be up to 15m deep, formed by the accumulation of dead plant material which retain large volumes of water. Due to their waterlogged condition raised bogs hold and preserve archaeological and organic remains. Boglands are a living archive of our past climate, ecology and archaeology.
Bogs act as a carbon store reducing greenhouse gases and “reducing” climate change.
|Fig 3, Raised Bog Pool
with open water
Raised Bogs are rare in the European Union (EU) are becoming increasing scare and under threat in Ireland. Raised bogs have been developing in Ireland for thousands of years and once covered over 310,000 ha. However due to extensive peat harvesting for fuel and horticulture as well as drainage for agriculture and forestry much of the original raised bog habitat has been lost (approx 92%). Only a small percentage of what remains is of conservation value.