Raised bogs, also called ombrotrophic bogs (ombrotrophe Moore), are acidic, wet habitats that are poor in mineral salts and are home to flora and fauna that can cope with such extreme conditions. Raised bogs, unlike fens, are exclusively fed by precipitation (ombrotrophy) and from mineral salts introduced from the air. They thus represent a special type of bog, hydrologically, ecologically and in terms of their development history, in which the growth of peat mosses over centuries or millennia plays a decisive role. They also differ in character from blanket bogs which are much thinner and occur in wetter, cloudier climatic zones.
Raised bogs are very threatened by peat cutting and pollution by mineral salts from the surrounding land (due to agriculture and industry). There are hardly any raised bogs today that are still living and growing. The last great raised bog regions are found in western Siberia and Canada.
The term raised bog derives from the fact that this type of bog rises in height over time as a result of peat formation. They are like sponges of peat moss, full of water, that form a more or less dome shape in the landscape. In Germany, the term Hochmoor ("high bog"), strictly refers only to the classical, lens-shaped bogs of northwest Germany. The bogs are not influenced by mineral-rich groundwater or surface water, but are fed exclusively by precipitation — mainly rainwater, hence their alternative German designation of Regenmoor or "rain-fed bog". Thus the latter refers to all bogs, not just those that are arched or only slightly arched, but which nevertheless are characterized by an extreme mineral salt deficiency and other resulting ecological properties.
A living raised bog needs a moist, balanced climate in which to grow. The quantity of precipitation has to be greater than the water losses through discharge and evaporation. In addition, the precipitation must be evenly spread through the year.
Raised bogs in Europe have been developing for about 11,000 years, since the beginning of the Holocene and after the retreat of the last ice sheet. As far as their origins are concerned, a distinction is made between lake mires or 'siltation-formed raised bogs' (Verlandungshochmoore) and 'mire-formed raised bogs' (wurzelechte Hochmoore). The former emerged in a secondary process after the silting up of lakes or oxbows (see illustration on the right in the sequence). At first, fens emerged under the influence of groundwater (minerotrophy). Oxygen deficiencies and high acidity in the constantly moist substrate inhibited the decomposition of dead plant parts and led to peat formation.
Thus the raised bog rises very slowly above the groundwater level, hence its name. As the resulting peat slowly rises above the influence of mineral salts in the groundwater, it reaches a point where the development of the raised bog begins to change in nature; that is, the bog now becomes fed solely by rainwater, which is low in salt. By contrast, mire-formed raised bogs are created directly on the mineral substrate of low-salt areas without having been initially formed as fens (see figure on the left in the sequence). They are formed either as a primary bog due to the erosion of previously dry mineral soils, for example due to clearing, climate change or infiltration, or as a secondary process as a result of the growth of a raised bog on neighbouring mineral soil. The formation of a typical raised bog is a very slow process, which lasts from centuries to a thousand years even in favourable, undisturbed conditions. Furthermore, there are a number of transitional and intermediate bogs, which in different ways combine characteristics of both raised bogs and fens. (See bog.)
The main constituents of the peat are rootless peat mosses that grow slowly in height whilst at the same time the lower layer becomes peat as the air is excluded. Depending on the geographical location, various species of peat moss are involved in making a raised bog. The growth rate of the peat layer is only about a millimetre per year.
Growing bogs can be divided into two layers. The 'acrotelm' (Greek: akros = highest; telma = bog) is the upper part and includes the vegetation layer and the bog 'floor'. Here fresh organic substances (peat formation horizon) are created by the growth and dying of plant elements. The "catotelm" (Greek: kato = below) is the underlying water-saturated part with less biological activity. This layer is counted as a geological subsoil due to the small earth-forming processes that are still going on and is known as the peat preservation horizon (Torferhaltungshorizont). In raised bogs, the upper peat layer is called white peat, since it consists of largely undecomposed light brown peat mosses. The lower layer is black peat, which is already well humified and has a black-brown colour with still recognizable plant remains.
The formation of raised bogs is dependent on the climate, that is to say the amount of precipitation and rate of evaporation, which in turn are decisively determined by the temperature. In addition, the relief of the terrain has an influence on the water discharge behaviour and thus the shape of a raised bog. This results in geographical limitations to the formation of raised bogs. Favourable conditions for the development of raised bogs are found mainly in North America (Canada and Alaska), Northern Europe and Western Siberia, South America, Southeast Asia and in the Amazon Basin. In these regions, bogs of all kinds and peat deposits of four million square kilometres have been formed, covering three percent of the earth's surface. In the southern hemisphere low-mineral-rich bogs are rarely formed from peat mosses. Only in the Tierra del Fuego do peat moss raised bogs exist. The most peaty countries in the tropics are found in Southeast Asia. In many cases it is not yet clear how these bogs have emerged as mosses are entirely absent here.
Coastal bogs (Planregenmoore) or Atlantic bogs, as their names suggest, tend to form close to the sea. In addition, in regions covered by blanket bog, there are also lightly convex coastal bogs with low energy surface relief in level locations. The distribution of coastal bogs in Europe extends from Ireland to the east via South Norway to Southwest Sweden and north to the Lofoten. In North America there are coastal bogs in the area of the Great Lakes (especially in Minnesota and Ontario). Coastal bogs are also fed exclusively by rain.
In the less oceanically influenced climatic regions of North-West Europe (lower precipitation), raised bogs take on the classical lens shape and are called plateau bogs or plateau raised bogs (Plateauregenmoore). They grow more strongly in the centre than at the margins. This results in the centre of the bog bulging, hence the name "raised bog". This bulging can be several metres high. As a result, the perimeter of the bog is more or less inclined, and is known as the rand. The sloping bog sides of larger bogs are traversed by drainage channels or soaks (Rüllen) through which excess water is discharged.
Other characteristic structures of these raised bogs are the flat, treeless raised bog core with its characteristic microrelief of shallow wet depressions or flarks (Schlenken) alternating with hummocks (Bülten) of drier peat moss. Larger accumulations of water in the middle of the bogs are called kolks or bog ponds (of humic acid-rich water); the wet area on the outer margins is known as a moat or lagg.
Genuine ombrotrophic bogs on the North German Plain are usually sharply divided into two layers: an underlying black peat layer, which is strongly decomposed, and an overlying white peat layer which is less decomposed. This difference is a result of changes in the hydrology of the bog. The white peat grew more rapidly under humid conditions than the black peat. This is attributed to a climate change with high precipitation and low evaporation around 1000 to 500 BC. As a result, the peat moss growth grew locally and the black peat/white peat boundary layer was formed, although this did not develop simultaneously in all raised bogs.
Raised bogs also occur in precipitation-rich upland regions at the montane and, more rarely, alpine levels (i.e. above the tree line). As a result of the sloping terrain, they often have a characteristic, asymmetric or non-concentric appearance. Mountain or upland bogs may be topographically divided into:
Kermi bogs (Kermimoore, Schildhochmoore, Strangmoore or Blankenmoore) or kermi raised bogs have only a slightly domed shape. The surface of the bog rises steadily from the broad lagg zone. Kermis have ridge-shaped hummocks of peat moss, that are aligned with the contours of the bog. The flarks or elongated depressions are generally tub-shaped and hardly distinguishable externally from kolks. In the central area of these bogs, there are always large kolks. In northern Russia and western Sibiria, kermis frequently occur in giant complexes where the bogs have grown into one another. Kermis are also found in Finland in the central and northern boreal forest zone.
String bogs or aapa fens (Aapamoore or Strangmoore) are typically found on the northern fringes of the distribution area for raised bogs, in the sub-polar zone, north of the 66th latitude in the northern hemisphere. Here, raised bogs only occur as islands within wetlands supplied by mineral soil water. On level ground these islands are irregularly distributed; on hillsides they form ridges parallel to the contours and at right angles to line of slope. The ridges separate boggy hollows of mineral soil known by the Finnish word, rimpis. The main distribution area for string bogs are the Scandinavian hills, central Finland, Karelia and north Sibiria. In North America, Alaska is the main location for string bogs, thanks to its cold continental climate. Frost action plays an important role in these bogs. On the ridges or hummocks, ground ice is found until early summer.
Palsa bogs (Palsamoore or Palsenmoore) are found on the margins of the Arctic permafrost soils (tundra). Here the ridges of the string bogs can grow into hummocks several metres high. Like string bogs, the so-called palsas frequently lie within peatlands fed by mineral soil water. Some are surrounded by water-filled, ditch-like hollows. Peat formation is limited; these bogs are peat deposits from warmer, interglacial periods and did not experience frost heaving of their inner core of ice until the climate became colder. These ice lenses increase in size from year to year as a result of freeze-thaw processes of the surrounding water. The low temperatures prevent full decomposition of the organic material.
Polygonal bogs (Polygonmoore) are widespread on the Arctic and sub-Arctic plains of Sibiria and North Americas and cover vast areas. They are associated with patterned peatland and ice wedges. A scanty layer of peat-forming vegetation can occur in the inner honeycomb-shaped areas of this frost pattern terrain (cryoturbation) and are fed during the short summers with sufficient moisture, because the meltwater is prevented from draining away by the raised polygonal margins. The peat layers can attain a thickness of 0.3 to 1 m (1.0–3.3 ft).
The west Siberian raised bog area covers 700,000 km2 (270,000 sq mi). The large bogs have domes in the centre up to 10 m (33 ft) high. They are predominantly of the kermi bog type. They represent probably the most important type of raised bog on earth. The Vasyugan Swamp in this region, is the largest bog system on earth and covers more than 50,000 km2 (19,000 sq mi). It is estimated to contain over 14 billion tonnes of peat deposits.
The largest central European raised bog areas are the southern North Sea coastal area and the Alpine Foreland. As in North America there is a succession of raised bog types along the line of descent towards the ocean, from northwest to southeast. As a result of peat use, raised bogs have been harvested for peat and cultivated, apart from a few remnants (less than 10% of the original area). The largest contiguous raised bog in central Europe was the Bourtange Moor, which originally covered an area of about 2,300 km² including the Dutch portion, but only small sections remain. The largest remaining raised bog in northern Europe is the 76 km² Lille Vildmose. Other large raised bogs are the Teufelsmoor northeast of Bremen, the Vehnemoor (exhausted) and the Esterweger Dose (formerly about 80 km², exhausted) between Oldenburg and Papenburg. The raised bogs of the Central Uplands of the Harz, Solling, Thuringian Forest (Großer Beerberg, Schneekopf - Teufelsbad, Fichtenkopf, Saukopf), Giant Mountains, Ore Mountains, Fichtel and Rhön (Black Moor, Red Moor) are, by contract, comparatively small. In the Black Forest the Wildseemoor has been protected and, in the Vosges on le Tanet, north of the Col de la Schlucht a large area has been protected. The Alpine Foreland, which was formed by ice-age glaciation, is also rich in peatland. The Wurzacher Ried (Haidgauer Regenmoorschild) is considered the largest and best preserved raised bog in central Europe. Other raised bogs and peatland areas include the Federsee, the High Fens on the Germano-Belgian border, the Ewiges Meer near Aurich and the Lengener Meer near Wiesmoor. In 2003, Estonia exported 3.6 million m³ of peat for west European garden use, more than 60% of the state production. In Lithuania 60% of the usable peat area has been prepared for extraction or is already exhausted.
Lough Lurgeen Bog and Glenamaddy Turlough Bog contains very good examples of the Annex 1 habitats: active raised bog, turlough (both priority habitats), degraded raised bog (capable of regeneration) and vegetation of depressions (rhynchosporion). These habitats are considered to be among the best examples in Ireland due to their relatively large size and the generally low levels of disturbance. In the Natura form compiled for the site active raised bog was given a rating of A (Excellent value) which emphasises the importance of the site. Raised bog habitats are now very rare in Europe and it has recently been estimated that the Republic of Ireland contains 50% of the relatively intact oceanic raised bog systems in Europe.
The site contains the second largest area of intact raised bog surface in Ireland. The combination of raised bog, oligotrophic lake and turlough habitats is unique in Ireland and thus the entire system is very important from both a hydrological and ecological perspective.
A region of peatland extends from Alaska in the west to the coast of the Atlantic in the east, and is comparable in size to that of West Siberia. A zone of domed raised bogs adjoins the zones of palsa bogs and string fens. In the direction of descent towards the ocean, blanket bogs occur east of Hudson Bay. These are superseded towards the west by plateau bogs in the area of the large lakes and, eventually, by kermi bogs.
Ballynahone Bog (from Irish Baile na hAbhann, meaning 'townland of the river') is a raised bog, situated in County Londonderry, Northern Ireland, about 3 km south of Maghera, on low-lying ground immediately north of the Moyola River about 14 km from its mouth at Lough Neagh. It is one of the largest lowland raised bogs in Northern Ireland.Black Bog
Black Bog is a raised bog in County Tyrone, Northern Ireland, situated about 17km west of Cookstown. It is one of the two largest intact active bogs in Northern Ireland with hummock and hollow pool complexes and represents one of the best examples of this habitat type in the United Kingdom.Blawhorn Moss
Blawhorn Moss is a raised bog located to the northwest of the village of Blackridge, about 6 kilometres (3.7 mi) west of Armadale in the council area of West Lothian in central Scotland. A large part of Blawhorn Moss, extending to around 69 hectares, has been managed as a National Nature Reserve by SNH since 1980. In 2001, SNH purchased a further 40 hectares, which was declared as an extension to the existing National Nature Reserve in 2008. It is the largest and least disturbed raised bog in the Lothians.The NNR is classified as a Category IV protected area by the International Union for Conservation of Nature, and is also designated as both a Special Area of Conservation and a Site of Special Scientific Interest. The reserve is owned and managed by Scottish Natural Heritage (SNH).Bog
A bog or bogland is a wetland that accumulates peat, a deposit of dead plant material—often mosses, and in a majority of cases, sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, quagmire, and muskeg; alkaline mires are called fens. They are frequently covered in ericaceous shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink.Bogs occur where the water at the ground surface is acidic and low in nutrients. In some cases, the water is derived entirely from precipitation, in which case they are termed ombrotrophic (cloud-fed). Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general, the low fertility and cool climate result in relatively slow plant growth, but decay is even slower owing to the saturated soil. Hence, peat accumulates. Large areas of the landscape can be covered many meters deep in peat.Bogs have distinctive assemblages of animal, fungal and plant species, and are of high importance for biodiversity, particularly in landscapes that are otherwise settled and farmed.Bog of Allen
The Bog of Allen (Móin Alúine in Irish) is a large raised bog in the centre of Ireland between the rivers Liffey and Shannon.
The bog's 958 square kilometers (370 square miles) stretch into County Offaly, County Meath, County Kildare, County Laois, and County Westmeath. Peat is mechanically harvested on a large scale by Bórd na Móna, the government-owned peat production industry. The area has miles of narrow gauge industrial railways for transporting turf to processing plants and turf powered power plants. In addition, the cutover portions are used as area for grazing. The bog is crossed by the Grand Canal and the Royal Canal.Bog pond
A bog pond (German: Moorauge) is a waterbody in the middle of a raised or kettle bog, formerly also in percolating mires (Durchströmungsmooren). It is also called a bog eye, raised bog kolk, bog kolk or just kolk.
Bog ponds owe their existence to the growth of the bog body and are thus of biogenic origin.
Brown bog ponds are surrounded by peat and receive their water exclusively from precipitation or from the large rain storage capacity of raised bogs. Such kolks generally represent the non-evaporating excess water of a bog. The central waterbody of these bogs exhibit almost no sedimentation.
The accumulation of nutrients can lead to the formation of floating mats. Their vegetation differs from that of other structures in the bog. Usually the edges of the kolk are more nutrient-rich as a result of mineralisation processes caused by wave and wind action. Here, woody plants such as downy birch (Betula pubescens) and other species of plant e.g. purple moor grass (Molinia caerulea) may establish that otherwise are missing on the central areas of intact bogs. The bog water is brown, nutrient-poor, humic acid rich and lime-free (dystrophic).Cors Caron
Cors Caron is a raised bog in Ceredigion, Wales. Cors is the Welsh word for "bog": the site is also known as Tregaron Bog, being near the small town of Tregaron. Cors Caron covers an area of approximately 862 acres (349 ha). Cors Caron represents the most intact surviving example of a raised bog landscape in the United Kingdom. About 44 different species groups inhabit the area including various land and aquatic plants, fish, insects, crustaceans, lichen, fungi, terrestrial mammals and birds.Flanders Moss
Flanders Moss (Scottish Gaelic: A’ Mhòine Fhlànrasach) is an area of raised bog lying in the Carse of Forth in west Stirlingshire, Scotland. The villages of Thornhill and Port of Menteith lie to the north with the villages of Kippen and Buchlyvie lying to the south. The moss is a National Nature Reserve, managed by Scottish Natural Heritage. Formed on the Carse of Stirling over 8000 years ago, it is an internationally important habitat currently undergoing active restoration.
The eastern part of Flanders Moss is the largest raised bog in Europe to remain in a predominantly near-natural state.As well as being an important habitat for wildlife, Flanders Moss also plays a key role for carbon sequestration acting as a carbon sink.Himmerland
Himmerland is a peninsula in northeastern Jutland, Denmark. It is delimited to the north and the west by the Limfjord, to the east by the Kattegat, and to the south by the Mariager Fjord. The largest city is Aalborg; smaller towns include Hobro, Aars, Løgstør, Støvring and Nibe. In northeastern Himmerland is the Lille Vildmose, Denmark's largest raised bog, which sustains a rich bird life of international importance.Kilkerrin
Kilkerrin (Irish: Cill Choirín) is a village in County Galway, Ireland. It is situated on the R364 regional road 6 km south of the town of Glenamaddy. Notable features in the area are Kiltullagh Lake and the Lough Lurgeen raised bog.Lille Vildmose
Lille Vildmose (meaning: “little wild bog”) is a raised bog also known as the East Himmerland Moor in the hinterland in the municipalities of Aalborg and Mariagerfjord, Denmark. It is the largest remaining raised bog in Northern Europe. The bog is a remnant of heathland that once extended south from Limfjorden to Rold Forest.List of National Natural Landmarks in Indiana
From List of National Natural Landmarks, these are the National Natural Landmarks in Indiana.Moine Mhòr
Moine Mhòr ("Great Moss" in Scottish Gaelic) encompasses a large area of raised bog in the Kilmartin Glen area of Argyll and Bute, Scotland. As well as raised bog there are areas of saltmarsh, brackish grassland, alder carr, fen and woodland, and the variety of habitats at Moine Mhòr provide important habitats for a variety of animal and plant species. The area was declared a National Nature Reserve (NNR) in 1987, and is now owned and managed by Scottish Natural Heritage (SNH). According to SNH lowland raised bogs like Moine Mhòr are some of the rarest and most threatened natural wildlife habitats in Europe, due to removal of peat, afforestation and reclamation of farmland.Around 8,000 people visit the Moine Mhòr NNR every year, with the reserve being popular with local people and school groups, as well as tourists visiting the nearby attractions of Kilmartin Glen and the Crinan Canal. A 600 m nature trail has been constructed at the northern edge of the reserve; other visitor facilities include a car park and picnic area.North Eifel
The North Eifel (German: Nordeifel), the northern part of the Eifel, a low mountain range in Germany and East Belgium, comprises the following six sub-regions:
Our Valley and
High Eifel.All elements belong to the Hohes Venn – Eifel Nature Park.
The raised bog of the Hohes Venn is particularly noteworthy. It was designated as a world heritage site by UNESCO. The Eifel Lake Plateau with the second largest dam in Germany, the Rur Valley Dam, lies in the centre of the North Eifel.
Also within the North Eifel are:
Eifel National Park,
Monschau Hedegerow Country (Monschauer Heckenland),
Hürtgen Forest and
Zitter Forest.Polistovsky Nature Reserve
Polistovsky Nature Reserve, Polistovsky Zapovednik (Russian: Полистовский заповедник) is a strict nature reserve (a zapovednik) in the northwest of Russia, located in Bezhanitsky and Loknyansky Districts of Pskov Oblast, in the Polist-Lovat Swamp System. The reserve is about 120 km southeast of the city of Pskov. It was formally established on May 25, 1994. Previously, it functioned as a zakaznik. The nature reserve is created to protect the raised bog ecosystems of the Northwestern Russia.Raheenmore Bog
Raheenmore Bog is a raised bog north-west of Daingean, County Offaly, in Ireland. Since the 1980s the greater part of the bog has been maintained as a 162 hectare Nature Reserve, which is currently managed by the National Parks and Wildlife Service. A Special Area of Conservation covers 182 ha, including some land in private ownership.Rdeysky Nature Reserve
Rdeysky Nature Reserve, Rdeysky Zapovednik (Russian: Рдейский заповедник) is a nature reserve (a zapovednik) in the northwest of Russia, located in Poddorsky and Kholmsky Districts of Novgorod Oblast, in the Polist-Lovat Swamp System. The reserve is about 180 km southeast of the city of Pskov. It was established on May 25, 1994. The nature reserve is created to protect the raised bog ecosystems of the Northwestern Russia.Rhode, County Offaly
Rhode (historically spelt Road, from Irish: Ród) is a village in County Offaly, Ireland. It is situated on the R400 at its junction with the R441 which leads to Edenderry, the nearest town, located 12 km east of Rhode.
The village is on an "island" of high ground surrounded by an expanse of raised bog which forms part of the Bog of Allen.
The modern village of Rhode developed around a peat-burning power plant operated by the Electricity Supply Board which was supplied with milled peat by Bord na Móna. The plant was shut down in 2003 and its cooling towers were demolished on March 16, 2004, removing a highly visible landmark.Torronsuo National Park
Torronsuo National Park (Finnish: Torronsuon kansallispuisto) is a national park in the Tavastia Proper region of Finland. Even before its declaration as a national park in 1990, the near-natural state swamp area was a protected area. Its area is 25.5 square kilometres (9.85 sq mi).
The park area is a typical ombrotrophic raised bog – a thick turf layer with its middle part raising above its edges. The turf layer is one of the thickest measured among Finnish bogs, locally extending to 12 metres (39 ft).
Torronsuo is valuable for its birdlife and butterfly species. Roughly a hundred species nest in the area. Part of the birds and insects are species that typically live in the northern areas, and they aren't seen much elsewhere in southern Finland.