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"A fen is a wetland that is largely sourced from groundwater, including springs and seepages etc, or surface water, such as rivers or rainwater runoff.
Fens are usually peat-forming habitats and the water table is near the ground surface for much of the year.
The term ‘fen ‘encompasses many different types of wetland, from poor-fens, such as valley mires, to rich-fens, including alkaline fen. Although bogs share many of the same plants and animals as fens, they are predominantly rainwater-fed." - Freshwater Habitats Trust: Fens
"It is estimated that 3,400 km2 of fen was present in England in the 17th century, but only 10 km2 remains today.
The cause of this decline is complex and the result of a number of factors. Lack of management and livestock grazing has led to many fens being encroached by trees and scrub. The use of fertilisers in nearby arable land is also impacting on fens, which have impermeable surfaces, preventing infiltration. Many historic fens have been drained to use the land for commercial purposes, including farming.
Climate change brings additional threats, with less reliable rainfall and increasing summer droughts that could affect the water table and threaten the survival of our remaining fens." - Freshwater Habitats Trust: Fens
"With a high peat content and water table, fens are highly diverse habitats, supporting many endangered plant and animal species.
Some examples of rare fen plant species are Slender Green Feather Moss (Hamatocaulis vernicosus), Crested Buckler-fern (Dryopteris cristata) and Fen Orchid (Liparis loeselii). Fens are home to a very special invertebrate community, with astonishing diversity in groups like, beetles, dragonflies, molluscs, moths and soldierflies. Among the vertebrate visitors of fens, we can find Water Vole, Bittern and several species of newts." - Freshwater Habitats Trust: Fens
"Before the era of livestock farming (Neolithic times), no domestic cattle grazed in wetlands. Instead, fens and/or neighboring woodlands in Europe were grazed by large ungulates such as Elk (Alces alces) and Red deer (Cervus elaphus; Cromsigt 2000), and in North America, Moose (Alces alces) and Wapiti (Cervus elaphus canadensis; Jackson 1961)." - Biodiversity Management of Fens and Fen Meadows by Grazing, Cutting and Burning
"In addition, fens usually form peat, a layer of organic material formed by the partial decomposition of plant material that is a vital carbon sink. This also helps with flood control and providing habitat for wetland wildlife. " - Freshwater Habitats Trust: Fens
While fens are home to a diverse array of species year-round, they are also important resting and refueling spots for migratory wildlife, particularly songbirds and water fowl.
"Cattle defoliate plants, trample vegetation (Arnesen 1999), alter soil structure (Murray 1997), and crush sedge tussocks with their hooves, which can allow the invasion of shrubs. Cattle maintain palatable shrub species in a state of small stature while grazing, but if the cattle subsequently are removed from the fen, the shrubs may grow prolifically to form a dense stand of shrubs (Middleton 2002a). Unpalatable tree species such as Alder (Alnus glutinosa) may even grow up under constant grazing management with low animal numbers because cattle largely avoid eating the saplings (BunzelDrücke 1996; Holsten 2003). From a conservation perspective, the invasion of trees in fen areas is mostly regarded as a problem because the biodiversity of characteristic, low-stature fen species is reduced because of low light availability (Kotowski & Van Diggelen 2004). At the same time, cattle create ‘lawns’ of regularly grazed sites and ‘tussocks’ that are rarely grazed (McNaughton 1984; J.P. Bakker et al. 1984), so that cattle increase the spatial heterogeneity of habitats for plants and animals. In wet meadows, small mammal density was positively affected by cattle at intermediate grazing intensities (ca. 0.5 cattle/ha) and negatively by much higher or lower stocking densities (Schmidt et al. 2005). The species number and abundances of grasshoppers, butterflies, solitary bees and wasps was higher in pastures with lower stocking rates than in intensively grazed pastures (0.7 cattle/ha vs. 3.2 cattle/ha, respectively; Kruess & Tscharntke 2002). However, other studies of freshwater wetlands indicate that grazing intensity hardly affects the species richness of invertebrate communities (Steinman et al. 2003)." - Biodiversity Management of Fens and Fen Meadows by Grazing, Cutting and Burning
"The role of cattle in introducing non-native species into wetlands also needs to be considered in the discussion of biodiversity conservation in fens. Especially in North America, cattle have a significant role in introducing non-native species into fens. Some of the non-native species of seeds that are found in the manure of cattle (Mt. Pleasant & Schlather 1994) are maintained in the seed banks of fens for decades after abandonment by cattle (Middleton 2002a). We are not aware of any studies that examine the role of cattle in maintaining native biodiversity in fens in North America." - Biodiversity Management of Fens and Fen Meadows by Grazing, Cutting and Burning
Data also shows that "...high grazing pressure increases soil degradation due to cattle trampling. If there are any benefits to the biodiversity of fens from cattle grazing, these benefits would be realized only at very low stocking densities. Because of the irreversibility of soil degradation..."
Peat is often used as a growing medium in nurseries and gardens.
"water extraction nearby or the prevention of flooding from nearby rivers and by the nutrients from agricultural run-off. At some key sites, attempts have been made to maintain higher water tables, including irrigation and the installation of an impermeable membrane." - The Wildlife Trust: Lowland Fen
Legal protections and programs such as the Great Fen Project can help protect fens from future harm, while we work on solutions to protect them from pollution and over-extraction.
By making informed changes in how to allocate and use water, we can drastically reduce our over extraction of water, while actually boosting food security.
"In North America, fire was probably a much more structuring factor than grazing during the presettlement period. Before the defeat of Chief Black Hawk in 1832, American Indians and lightning fires annually burned fens in Wisconsin and other parts of the Middle Western United States (Curtis 1959; Prince 1997). Also, farmers had once burned pastured fens to improve forage quality, but in places such as southern Wisconsin, this practice abruptly ceased after World War II (Middleton 2002b). After that time, many fens became less species-rich and/ or encroached by woody species. Fire in North-American fens can be considered a natural disturbance, and should be considered to help maintain the biodiversity of fens.
Fire is generally considered destructive in peatlands in Europe (Klimkowska 2004), mainly because the peat may catch fire, particularly in drained fens. Once set, the fire may smolder for long periods of time (Anon. 2005). Nevertheless, fire set by lightning strike must have once burned undrained fens in the European landscape as it is reported for mires in Finland (Pitkänen et al. 1999), and so could be considered as a natural disturbance at least for the management of undrained fens. The burning of sedge meadows was regularly practiced in eastern Europe (Poland and Belarus) until recently (Kloskowski & Krogulec 1999; Kozulin & Flade 1999)." - Biodiversity Management of Fens and Fen Meadows by Grazing, Cutting and Burning
"The re-introduction of appropriate native ungulates in fens could be beneficial, especially in relatively unpopulated regions. Native ungulates require large areas in which to range, and so it is not likely that these could be re-introduced successfully in urbanized areas. Other native ungulates could be re-introduced to fens in both Europe and North America. In North America, moose may once have been important herbivores in fens, and could be reintroduced in remote parts of North America. Moose are dangerous animals and not especially welcome in urbanized areas. Elk eat woody vegetation in European fens (Bokdam & van Braekel 2002), so that these could be useful to manage woody species in fens. Free ranging wild animals such as red deer in Central Europe have little influence on sedge-dominated fen vegetation because hunting pressure and disturbance by people keep the animals in the forests during daytime. When red deer enter open habitat at night, they prefer food of high energy and protein content (Wagenknecht 2000) and avoid vegetation dominated by sedges because of their low nutritional value.
... While Aurochs and wild horses no longer exist, Heck cattle and Polish Konik horses are available. Heck cattle were bred in an attempt to redevelop the aurochs by mixing various European cattle races. Polish Konik horses are a primitive horse breed from Poland and are sometimes used to graze fens in Europe (e.g. Wicken Fen, Norfolk and Suffolk Broads, England). Both Heck cattle and Polish Konik horses should be regarded as primitive breeds only, and not directly equivalent to their wild ancestors. Both Heck cattle and Konik horses avoid nutrient-poor sedge vegetation in the same way as red deer when nutrient-rich food is available (Vulink 2001). However, both of these large ungulate species resemble their extinct wild ancestors, and so have been introduced to some nature reserves in Europe (J.P. Bakker 1989)." - Biodiversity Management of Fens and Fen Meadows by Grazing, Cutting and Burning
Biodiversity Management of Fens and Fen Meadows by Grazing, Cutting and Burning (PDF) "This paper is a review of the literature on the effects of grazing, fire and cutting on fens, to explore the relationship between management and biodiversity in fens."
Freshwater Habitats Trust "We're building a national network of wilder, wetter, cleaner, connected freshwaters"
USGS Wetland and Aquatic Research Center "WARC conducts relevant and objective research, develops new approaches and technologies, and disseminates scientific information needed to understand, manage, conserve, and restore wetlands and other aquatic and coastal ecosystems and their associated plant and animal communities throughout the nation and the world."
The National Trust: Freshwater Community Grant Fund "Grants of £500 to £5,000 are available for initiatives that create, look after or improve local freshwater habitats and provide opportunities for people to connect with nature."