Rich fen
Encyclopedia
Rich fen is a type of fen
Fen
A fen is a type of wetland fed by mineral-rich surface water or groundwater. Fens are characterised by their water chemistry, which is neutral or alkaline, with relatively high dissolved mineral levels but few other plant nutrients...

 that is rich in calcium, with a pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

 around 6-8, but nutrient poor. These special conditions have given the rich fens a specialized and species rich flora, which often consists of orchids, sedges and mosses (Rydin et al. 1999). The rich fens are often classified into the categories moderately rich fen and extremely rich fen. The extremely rich fens have a higher pH and more vascular plants (Rydin et al. 1999).

Threats

Historically rich fens have been used as meadows and pastures, but the practices ceased during the 20th century (Emanuelsson 2009). Many wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

 areas, among them the rich fens, were drained in the 19th and 20th century to create new agricultural land or to increase productivity in the forestry (Emanuelsson 2009). There are several other threats though, that might cause degradation and loss of rich fens such as acidification, eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...

and overgrowth by trees and bushes because of lack of management. Habitat fragmentation is an ongoing threat that leads to reduced connectivity within the landscape. Small and isolated fragments hold in general fewer species than larger and less isolated areas. One reason is that it is more difficult for the species to disperse between the isolated fragments (Hunter et al. 2007).
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