Poor fen

A poor fen (also known as transitional bog, transitional mire or sedge mire) is a natural wetland habitat, supporting a dense carpet of mosses and sedges. It develops where the water is fairly acidic and has very few plant nutrients.[1] Poor fen is intermediate between the taller vegetation of fen, which occurs where the water is much less acidic, and the short, mossy vegetation of bog, which is even more acidic.

Formation of bogs (mesotrophic) In the climatic zone (taiga, forest-tundra) of the Arkhangelsk region. 1
The development of fen (mesotrophic) swamp forests during the dry season. Summer 2018. A strong decrease of groundwater level and the feed stream. In the climatic zone (taiga, forest tundra) of the Arkhangelsk region.


Poor fen occurs where the ground is permanently wet with nutrient-poor water which is somewhat acidic. It occurs around springs on mountain slopes, in places where neutral water enters more acidic bogs, and in complex with wet acidic grassland.[1]

The organic soils of poor fens are composed of peat.[2] As with all peatlands, the rate of plant decomposition is slower than accumulation under wetland conditions. As the peat surface thickens, the plant community changes in response to lower nutrient availability, and increasingly acidic and anaerobic chemistry.[3]

Poor fen is usually grazed by wild animals or livestock, which prevents ecological succession to wet woodland.

Natural disturbance factors influencing poor fens include fire, flooding, windthrow, and insects. Similar to grazing, a natural fire regime can prevent succession to woodland. In the absence of fire, a thick layer of leaf litter can encroach on the open mire which in turn stifles fen vegetation.[2]


Apis mellifera on Potentilla palustris
The marsh cinquefoil (Potentilla palustris)

Poor fens are covered with peat-forming Sphagnum mosses[3] such as Sphagnum angustifolium, Sphagnum fallax and Sphagnum magellanicum, while other brown mosses can also be frequent, such as Polytrichum commune. Mosses combine with a high abundance of sedges such as Carex canescens, Carex echinata, Carex nigra, Carex lasiocarpa, Eriophorum scheuchzeri (white cottongrass) and Trichophorum cespitosum (tufted bulrush). Other abundant plants are Andromeda polifolia (bog-rosemary), Betula nana (dwarf birch), Dactylorhiza maculata (heath-spotted orchid), Eriophorum vaginatum (hare's-tail cottongrass), Potentilla erecta (common cinquefoil), and Vaccinium oxycoccos (bog cranberry).[1]

See also


  1. ^ a b c "D2.2a Poor fen" (PDF). European Red List of Habitats - Mires Working Group. Luxembourg: European Union. 2016. Retrieved 2019-01-10. type of mire, fed by throughput of acid, nutrient-poor ground water
  2. ^ a b "Poor Fen". Natural Communities of Michigan: Classification and Description. Michigan Natural Features Inventory, Report No. 2007-21. Lansing: Michigan State University. 2007. Retrieved 2019-01-10.
  3. ^ a b "Chapter 7: Natural Communities, Aquatic Features, And Selected Habitats" (PDF). PUBSS-1131H Complete Ecological Landscapes of Wisconsin: An assessment of ecological resources and a guide to planning sustainable management. Madison: Department of Natural Resources. 2017. pp. 126–128.
A Directory of Important Wetlands in Australia

A Directory of Important Wetlands in Australia (DIWA) is a list of wetlands of national importance to Australia. Intended to augment the list of wetlands of international importance under the Ramsar Convention, it was formerly published in report form, but is now essentially an online publication. Wetlands that appear in the Directory are commonly referred to as "DIWA wetlands" or "Directory wetlands".

Ballynahone Bog

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.


Base-richness in ecology is the level in water or soil of chemical bases, such as calcium or magnesium ions. Many organisms are restricted to base-rich environments. Chemical bases are alkalis, and so base-rich environments are neutral or alkaline. Because base-poor environments have few bases, they are dominated by environmental acids (usually organic acids) and so are acidic. However, the relationship between base-richness and acidity is not a rigid one – changes in the levels of acids (such as dissolved carbon dioxide) may significantly change acidity without affecting base-richness.

Base-rich terrestrial environments are characteristic of areas where the underlying rocks are limestone. Seawater is also base-rich, so maritime and marine environments are themselves base-rich.

Base-poor environments are characteristic of areas where the underlying rocks are sandstone or granite, or where the water is derived directly from rainfall (ombrotrophic).

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.

Cefn Blaenau

Cefn Blaenau is a 23-hectare Site of Special Scientific Interest in a small upland valley in Carmarthen & Dinefwr, Wales. It was designated an SSSI in 1989 primarily for its flush and spring vegetation as well as the diverse mosaic of unimproved pasture, ‘ffridd’ land (steeply sloping land between enclosed fields and open hills, often dominated by bracken or gorse), marshy grassland, wet heath, acid grassland, broadleaved woodland, streams, and small rock outcrops. These habitats, which are well represented at this site, have been greatly reduced in north Carmarthenshire due to land improvement, agricultural intensification, and afforestation. Only about 140 hectares of flush and spring vegetation remain in the county.

The headwaters of the River Marlais (a tributary of the Cothi) run through the valley. The valley bottom has a series of mires merging into areas of wet heathy pasture dominated by purple moor-grass (Molinia caerulea) and rich in sedges. In the very wet, flushed mire areas there is an abundance of bog-mosses (Sphagnum spp.) with other localized plants such as marsh St John’s-wort (Hypericum elodes), round-leaved sundew (Drosera rotundifolia), common butterwort (Pinguicula vulgaris), and bog pondweed (Potamogeton polygonifolius).

At the base of the valley slopes there are boggy areas with common cottongrass (Eriophorum angustifolium), cross-leaved heath (Erica tetralix), common bilberry (Vaccinium myrtillus), marsh lousewort (Pedicularis palustris), and many-stalked spike-rush (Eleocharis multicaulis). The wet pasture supports uncommon species such as whorled caraway (Carum verticillatum), bog asphodel (Narthecium ossifragum), and heath spotted-orchid (Dactylorhiza maculata subsp. ericetorum).

Along streamsides, linear areas of poor-fen vegetation occur, including various rushes (Juncus spp.), ragged-robin (Lychnis flos-cuculi), marsh thistle (Cirsium palustre), greater bird's-foot-trefoil (Lotus uliginosus), marsh bedstraw (Galium palustre), sneezewort (Achillea ptarmica), marsh marigold (Caltha palustris), meadowsweet (Filipendula ulmaria), meadow vetchling (Lathyrus pratensis), devil's-bit scabious (Succisa pratensis), and lady-fern (Athyrium filix-femina). More open areas along these streamsides favour the uncommon ivy-leaved bellflower (Wahlenbergia hederacea) and bog pimpernel (Anagallis tenella).

The drier valley slopes have grazed acidic grassland characterized by tormentil (Potentilla erecta), wavy hair-grass (Deschampsia flexuosa), heath bedstraw (Galium saxatile), pig nut (Conopodium majus), and mosses (Polytrichum spp.). Distinctive wet flushes descend these dry slopes and, where there is a deeper accumulation of soil, bracken (Pteridium aquilinum) is dominant, interspersed with grass-heath areas and willow and hawthorn scrub. These ffridd areas are of importance for birds, particularly nesting whinchat, tree pipit, yellowhammer, linnet, curlew, and grasshopper warbler. Red kites, buzzards, sparrow hawks, kestrels, and goshawks are a common sight in the valley.

On the south-facing slopes of the valley, adjacent to the SSSI, there are a number of traditionally managed hay meadows where various wildflowers are present, such as meadow buttercup (Ranunculus acris), oxeye daisy (Chrysanthemum leucanthemum), yarrow (Achillea millefolium), black knapweed (Centaurea nigra), self-heal (Prunella vulgaris), red clover (Trifolium pratense), yellow rattle (Rhinanthus minor), common eyebright (Euphrasia nemorosa), common cat’s ear (Hypochaeris radicata), and smooth hawksbeard (Crepis capillaris).

Four species of fritillary butterfly – marsh (Eurodryas aurinia), small pearl-bordered (Boloria selene), dark green (Argynnis aglaja), and silver-washed (Argynnis paphia) – have been noted. The marsh and small pearl-bordered fritillaries occur in the wet pastures, whilst the dark green is found on the drier bracken slopes and the silver-washed in the tree canopy. All have declined nationally and are local species, now principally of south-western Britain. Rare and also present is the brown hairstreak (Thecla betulae), while the small copper (Lycaena phlaeas) and green hairstreak (Callophrys rubi) are notably abundant.

Another species of note, found in the wet flushed areas, is the nationally uncommon keeled skimmer dragonfly (Orthetrum coerulescens). This is a species of southern wet heathlands whose larvae develop in the wet mud of base-enriched flushes or bog pools. The valley is particularly rich in Odonata species: dragonflies recorded include the emperor (Anax imperator), golden-ringed (Cordulegaster boltonii), broad-bodied chaser (Libellula depressa), four-spotted chaser (Libellula quadrimaculata), southern hawker (Aeshna cyanea), common hawker (Aeshna juncea), black-tailed skimmer (Orthetrum cancellatum), common darter (Sympetrum striolatum), and black darter (Sympetrum danae); damselflies include the large red (Pyrrhosoma nymphula), azure (Coenagrion puella), emerald (Lestes sponsa), common blue (Enallagma cyathigerum), blue-tailed (Ischnura elegans), scarce blue-tailed (Ischnura pumilio), and beautiful demoiselle (Calopteryx virgo).

The area is home to a good population of mustelids, such as badger, otter, weasel, stoat, polecat, and pine marten. Brown hares are also present.

The site is under private ownership and there is no public access, except with the permission of the owners.

Dorothy Lake State Natural Area

Dorothy Lake State Natural Area is a Wisconsin Department of Natural Resources-designated State Natural Area featuring forested end moraine topography, with many steep-sided ridges and depressions. This results in a diverse mosaic of natural communities, including forests, swamps, fens, lakes, and streams.


A fen is one of the main types of wetland, the others being grassy marshes, forested swamps, and peaty bogs. Along with bogs, fens are a kind of mire. Fens are minerotrophic peatlands, usually fed by mineral-rich surface water or groundwater. They are characterised by their distinct water chemistry, which is pH neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients. They are usually dominated by grasses and sedges, and typically have brown mosses in general including Scorpidium or Drepanocladus. Fens frequently have a high diversity of other plant species including carnivorous plants such as Pinguicula. They may also occur along large lakes and rivers where seasonal changes in water level maintain wet soils with few woody plants. The distribution of individual species of fen plants is often closely connected to water regimes and nutrient concentrations.Fens have a characteristic set of plant species, which sometimes provide the best indicators of environmental conditions. For example, fen indicator species in New York State include Carex flava, Cladium mariscoides, Potentilla fruticosa, Pogonia ophioglossoides and Parnassia glauca.Fens are distinguished from bogs, which are acidic, low in minerals, and usually dominated by sedges and shrubs, along with abundant mosses in the genus Sphagnum. Bogs also tend to exist on dome-shaped landmasses where they receive almost all of their usually-abundant moisture from rainfall, whereas fens appear on slopes, flats, or depressions and are fed by surface and underground water in addition to rain.

Fens have been damaged in the past by land drainage, and also by peat cutting. Some are now being carefully restored with modern management methods. The principal challenges are to restore natural water flow regimes, to maintain the quality of water, and to prevent invasion by woody plants.

Goss Moor

Goss Moor is a National Nature Reserve in Cornwall, England, located 12 kilometres (7.5 mi) south-west of Bodmin in the parishes of St Dennis, St Columb Major, Roche and St Enoder. It is the largest continuous mire complex in south-west Britain and consists of mainly peatland and lowland heath. Together with the neighbouring moor to the east, it forms the Goss And Tregoss Moors Site of Special Scientific Interest (SSSI), as well as the Breney Common and Goss and Tregoss Moors Special Area of Conservation (SAC).

Helophilus hybridus

Helophilus hybridus is a hoverfly.

It is a Palearctic species.

Lough Derravaragh

Lough Derravaragh (Irish: Loch Dairbhreach) is a lough in County Westmeath, Ireland, north of Mullingar between Castlepollard, Crookedwood and Multyfarnham.

Lough Derravaragh sits on the River Inny which flows from Lough Sheelin on its way to the River Shannon. Shaped somewhat like Italy, it is a popular lake for angling and other watersports. The main public area is at Donore near Multyfarnham, where there is a caravan park and shop restaurant open in summer.

National Wetlands Inventory

The National Wetlands Inventory (NWI) was established by the United States Fish and Wildlife Service (FWS) to conduct a nationwide inventory of U.S. wetlands to provide biologists and others with information on the distribution and type of wetlands to aid in conservation efforts. To do this, the NWI developed a wetland classification system (Cowardin et al. 1979) that is now the official FWS wetland classification system and the Federal standard for wetland classification (adopted by the Federal Geographic Data Committee on July 29, 1996: 61 Federal Register 39465). The NWI also developed techniques for mapping and recording the inventory findings. The NWI relies on trained image analysts to identify and classify wetlands and deepwater habitats from aerial imagery. NWI started mapping wetlands at a small scale (1:250,000 map which covers an area the size of 128-1:24,000 USGS topographic maps or approximately 7,400 square miles). Eventually, large-scale (1:24K scale) maps became the standard product delivered by NWI. As computerized mapping and geospatial technology evolved, NWI discontinued production of paper maps in favor of distributing data via online "mapping tools" where information can be viewed and downloaded. Today, FWS serves its data via an on-line data discovery "Wetlands Mapper". GIS users can access wetlands data through an online wetland mapping service or download data for various applications (maps, data analyses, and reports). The techniques used by NWI have recently been adopted by the Federal Geographic Data Committee as the federal wetland mapping standard (FGDC Wetlands Subcommittee 2009). This standard applies to all federal grants involving wetland mapping to insure the data can be added to the Wetlands Layer of the National Spatial Data Infrastructure. NWI also produces national wetlands status and trends reports required by the United States Congress.

Neva River

The Neva (Russian: Нева́, IPA: [nʲɪˈva]) is a river in northwestern Russia flowing from Lake Ladoga through the western part of Leningrad Oblast (historical region of Ingria) to the Neva Bay of the Gulf of Finland. Despite its modest length of 74 kilometres (46 mi), it is the fourth largest river in Europe in terms of average discharge (after the Volga, the Danube and the Rhine).The Neva is the only river flowing from Lake Ladoga. It flows through the city of Saint Petersburg, three smaller towns of Shlisselburg, Kirovsk and Otradnoye, and dozens of settlements. The river is navigable throughout and is part of the Volga–Baltic Waterway and White Sea – Baltic Canal. It is a site of numerous major historical events, including the Battle of the Neva in 1240 which gave Alexander Nevsky his name, the founding of Saint Petersburg in 1703, and the Siege of Leningrad by the German army during World War II.


Ombrotrophic ("cloud-fed") soils or vegetation receive all of their water and nutrients from precipitation, rather than from streams or springs. Such environments are hydrologically isolated from the surrounding landscape, and since rain is acidic and very low in nutrients, they are home to organisms tolerant of acidic, low-nutrient environments. The vegetation of ombrotrophic peatlands is often bog, dominated by Sphagnum mosses. The hydrology of these environments are directly related to their climate, as precipitation is the water and nutrient source, and temperatures dictate how quickly water evaporates from these systems.Ombrotrophic circumstances may occur even in landscapes composed of limestone or other nutrient-rich substrates – for example, in high-rainfall areas, limestone boulders may be capped by acidic ombrotrophic bog vegetation. Epiphytic vegetation (plants growing on other plants) is ombrotrophic.

In contrast to ombrotrophic environments, minerotrophic environments are those where the water supply comes mainly from streams or springs. This water has flowed over or through rocks often acquiring dissolved chemicals which raise the nutrient levels and reduce the acidity, which leads to different vegetation such as fen or poor fen.

Platycheirus amplus

Platycheirus amplus is a Holarctic species of hoverfly found in wetlands, fens, moorland streams and bogs.

Ramsar Convention

The Ramsar Convention on Wetlands of International Importance especially as Waterfowl Habitat is an international treaty for the conservation and sustainable use of wetlands. It is also known as the Convention on Wetlands. It is named after the city of Ramsar in Iran, where the Convention was signed in 1971.

Every three years, representatives of the Contracting Parties meet as the Conference of the Contracting Parties (COP), the policy-making organ of the Convention which adopts decisions (Resolutions and Recommendations) to administer the work of the Convention and improve the way in which the Parties are able to implement its objectives. COP12 was held in Punta del Este, Uruguay, in 2015. COP13 was held in Dubai, United Arab Emirates, in October 2018.

Reed bed

Reed beds are natural habitats found in floodplains, waterlogged depressions, and

estuaries. Reed beds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As reed beds age, they build up a considerable litter layer that eventually rises above the water level and that ultimately provides opportunities for scrub or woodland invasion. Artificial reed beds are used to remove pollutants from grey water.

Sphagnum angustifolium

Sphagnum angustifolium, the fine bogmoss, is a species of peat moss with a Holarctic distribution.

Store Dyrehave

Store Dyrehave (literally Large Deer Park) is a forest immediately south of Hillerød, on both sides of Københavnsvej, in North Zealand, Denmark. Consisting of conifers and beech, it was enclosed with stone walls in 1619–28 as a royal deer park for hunting. In 1680, Christian V introduced a geometrical system of roads forming a star with eight branches for par force hunting. Although par force hunting was discontinued in 1777, the road system and numbered stone posts remain fully intact. Store Dyrehave is one of the three forests forming the Par force hunting landscape in North Zealand, a UNESCO World Heritage Site.

Watervalley Wetlands

The Watervalley Wetlands is a nationally important wetland system located in the Australian state of South Australia which consists of a series of contiguous wetlands, lying on 56.6 square kilometres (21.9 sq mi) of private land between the Coorong National Park and Gum Lagoon Conservation Park, in the state's south-east.

Classification systems

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