Liffey Head Bog EarthCache
-
Difficulty:
-
-
Terrain:
-
Size: 
(other)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
This EarthCache will bring you to Wicklow Mountains, the area called Liffey Head Bog.
Liffey Head Bog
Liffey Head Bog is an actively growing blanket bog within the Park. It is the best example of mountain blanket bog in the east of Ireland. It is situated in a hollow between Djouce, Kippure and Tonduff Mountains. Here you will find the headwaters of the Rivers Liffey, Dargle, Cloghoge and Dodder. This site is of international importance and has been designated a Special Area of Conservation. The wet bog surface and luxuriant growth of mosses and bog cottons show that it is an actively growing bog. Plants which are not common around Wicklow are found here such as Cranberry, Cowberry and Bog Rosemary. Liffey Head Bog has a system of flushes (water flows) which are an important part of the natural drainage system of the bog. These flushes often bring up nutrients from the mineral soil below the peat which support plant species not usually found on mountain blanket bog, such as Star Sedge, rushes and Devils Bit Scabious.
Source of River Liffey
Blanket Bog
Blanket bogs are found wherever there is high rainfall, which is typically in western Ireland and also in mountainous areas. They are called blanket bogs because of their appearance - from a distance they appear homogeneous and they hug the topography like a blanket. With almost 1 million hectares of Ireland covered by blanket bog, it is far more common than the smaller-scale raised bogs. Contrary to popular belief, blanket bogs are essentially a man-made feature, if inadvertent and aided somewhat by the climate. The graphic below is a cross-section of a hypothetical mountainside in Ireland showing how it evolved into a blanket bog.
Blanket bog is one of the most important habitats in the Park. Bogs consist of waterlogged soils upon which only a limited number of plants will survive. The Park contains the best example of bog in the east coast of Ireland.
The type of bog in the Park is known as mountain blanket bog, as it is found in mountainous areas (above 200m in altitude), where rainfall occurs over 175 days a year.
Blanket bogs originally covered 774,360ha of the land surface in Ireland. Extensive survey work has shown that there is only 21% of blanket bog left relatively intact. This is why the conserved areas of bogland are so important.
Formation of Blanket Bogs
Around 4000 years ago Ireland's climate became wetter and milder. Heavy rainfall caused minerals to be leached from the soil forming an impermeable layer in the soil known as an iron pan. Water couldn't soak through this layer, so the soil above the iron pan became waterlogged and peat began to form. Peat is brownish/black in colour and consists of approximately 90% water. Peat is made up of partially decomposed remains of dead plant material, which have accumulated on top of each other over thousands of years. The dead plant material consists of mosses, grasses and heathers. The roots of trees are often found in bogs. These trees are from ancient forests that were swallowed by the bog. The lack of oxygen prevents the complete breakdown of the plant material, resulting in the formation of peat. Peat only grows about 1mm a year but can reach depths of several metres. The name 'blanket bog' is derived from the fact that these bogs consist of a carpet of peat extending over large areas of land. Blanket bogs receive all their nutrients from rainfall, resulting in very acidic conditions (pH levels from 3.5 to 4.2). The lack of nutrients, low oxygen levels and high acidity means that there are only certain plants that will grow in this hostile environment. Many plants have special adaptations to help them survive.
Raised Bog
These develop from a lake or flat marshy area, over either non-acidic or acidic substrates. Over centuries there is a progression from open lake, to marsh, then fen (or on acidic substrates, valley bog) and carr, as silt or peat fill the lake. Eventually peat builds up to a level where the land surface is too flat for ground or surface water to reach the centre of the wetland. This part therefore becomes wholly rain-fed (ombrotrophic), and the resulting acidic conditions allow the development of bog (even if the substrate is non-acidic). The bog continues to form peat, and over time a shallow dome of bog peat develops: a raised bog. The dome is typically a few metres high in the centre, and is often surrounded by strips of fen or other wetland vegetation at the edges or along stream sides, where ground water can percolate into the wetland.
Raised bogs are found almost exclusively in central Ireland, chiefly in the Shannon basin. There are a few examples in Ulster and Munster, but the vast majority are to found in the midlands. Unlike blanket bogs, they were formed naturally. To understand raised bogs, one has to realise that Ireland's vegetation landscape is very young - it began to form only at the end of the Ice Age about 10,000 years ago. When the land surface was new, the glacial morraine left behind created a hummocky and chaotic plain which had poor drainage as a consequence. The depressions filled with water, creating thousands of tiny lakes. It was these tiny lakes that, over the 10 intervening millennia, have become the raised bogs. The graphic below is a cross-section of a hypothetical lake in central Ireland showing how it evolved into a Raised Bog.
Flora on the Bog
Sphagnum or peat mosses are specialised bog plants which colonise every part of the bog. Sphagnum grows upwards from the tips leaving the lower parts of the plant shaded. They die and become peat, resulting in the bog growing upwards above the surrounding landscape. Sphagnum mosses have adapted to the waterlogged conditions by being able to hold up to ten times their own weight in water. Sphagnum mosses have an ion exchange mechanism. They can absorb calcium ions from the rainwater they hold and release acidic hydrogen ions as a waste product. This creates a nutrient poor environment with high acidity allowing sphagnum to dominate. As other types of flora have to grow through the sphagnum, they tend to be stunted in growth. There are many varieties of sphagnum and colours range between greens, reds and yellows.
Peat harvesting
Like most habitats within the Park and in Ireland in general, Liffey Head Bog has been exploited in the past by man. In 1802, the Military Road was built across the bog, which opened it up for turf cutting by the local people. Turf is the name for peat which has been hand cut and dried out for use as a solid fuel for home heating. During World War II, turf cutting was carried out, in order to supply Dublin with fuel. By mid-1980s, machine exploitation of Liffey Head for turf was initiated by the landowner. However, this cutting was carried out in an area of relatively low ecological value. In 1986, a series of parallel drains were dug across an intact area of high ecological value. Protests by conservationists led to the acquisition of most of Liffey Head Bog by the State. This site became one of the core areas of the newly set up National Park. The earlier drainage and peat extraction had altered the hydrology of the bog. Waterlogged conditions are essential to the survival of a bog ecosystem. In 1995, extensive and costly work began on blocking the drains previously dug in order to rehabilitate the bog.
Why Conserve our Blanket Bog ?
Ireland possesses 8% of the world's blanket bog, so we are now the most important country in Europe for this type of habitat, this is why sites such as Liffey Head Bog are so important.
The peat layers of the bog preserve a record of their own growth and development and on a greater scale, provide insights into regional vegetation change, bog change and atmospheric pollution.
Blanket bogs are an important specialised ecosystem and a refuge for several rare plants, invertebrates and bird species. They are nesting grounds for some of our rare bird species. We hope that by encouraging a greater understanding of this complicated ecosystem, that we can help preserve some of Ireland's blanket bog for the future.
Source: Wicklow Mountains National Park, Wikipedia, Wesley Johnston's Site
Please send me your responses to the logging tasks, then go ahead and log this EarthCache. You do not need to wait for my response to post your log. If there is a problem with your log or logging tasks, I will contact you. Please do not include any information in your log that may spoil the logging tasks for others:
(Send your answers via geocaching profile)
1. What you see at the coordinates above? (EarthCache related)
2. What you can read at the wooden square post with a blue metal plaque? (You can find the post location in the Additional Waypoints section). There are at least two of them nearby.
3. What are the differences between a blanket and raised bog? Name at least two of them.
4. What is the one of the most common peat component?
5. How fast does peat grow? (per year)
Additional Hints
(No hints available.)