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H7140 - Transition mires and quaking bogs

General

Description habitat

This habitat type consists of peat-forming communities developed at the oligotrophic to mesotrophic water surfaces, with characteristics intermediate between soligenous and ombrogenous types. They present a large and diverse range of plant communities influenced by base-rich groundwater or surface water, which mixes with acidic, oliogotrophic precipitation. Two vegetation types are included in this habitat type in The Netherlands: 1) Quaking bog (association Scorpodio-Caricetum diandrae) and 2) Peat bog (association Pallavicinio-Sphagnetum). These communities are a developing stage of the hydrosere of ditches and peat pits in low laying peat areas. They are preceded by H3150 - Natural eutrophic lakes with Magnopotamion or Hydrocharition -type vegetation and succeeded by bush or forest, and possibly swamp heath #2.

General occurrence

This habitat type mainly can be found in Dutch low-lying peat lands. Quaking bog can mostly be found in low-lying peat lands near Pleistocene sandy grounds, as can be found in North West Overijssel, The Utrecht-Holland lake area and, in some cases, in Brabant near the Kempens plateau. Peat bog can be found more regularly. It develops in low lying peat areas after acidification of quaking bog and can also be found in peat areas with brackish water in North Holland #2

Environmental conditions

Peat bog comprises of a bottom layer consisting of large marsh plant rootstocks that are still in contact with eutrophic and base-rich water. Within the vegetation layer, eutrophication and base richness of the water decreases from the bottom upwards. The upper layer consists of various reed species. The bottom layer is related to the class of peat moor channels #1.
Quaking bog consists of a floating plant layer with various kinds of sedge and moss. These plant communities are restrained to contact zones where base rich mesotrophic surface water or groundwater mixes with acidic, oliogotrophic, precipitation water in a quiet surrounding (no waves). The water level should be more or less at a constant level. The communities can be found near pleistocene sandy grounds in low-lying peat areas in The Netherland. Yearly mowing is necessary for a prolonged preservation of this community #1.

Control and growth opportunities

Both plant communities are endangered in The Netherlands because of acidification, drying out and forestration. Forestration occurs spontaneously if the mowing management of peat bogs and quaking bods is no longer prolonguated. For Peat bog, former management measurements such as light grazing and adding of a thin sludge layer can enhance its species richness. In addition, restoration of the former maximum level in a 'boezem' can enhance the species-richness. For Quaking bog, yearly mowing proves to be helpful. Without mowing, the community converts into woods and brush wood. Eutrophication reduces the species richness of Quaking bog and less rare vegetation types will occur #1. For this habitat type, digging of new peat pits is essential for the survival of these plant communities as it is a part of the hydrosere process.

Dose-effect relations

These dose-effect relations have been based on information of plant communities belonging to this habitat type.

Flow chart

Dose-effect relations

surge	HSI
present	0
absent	1

Reference: #1

mowing policy	HSI
never	0
yearly	1

Reference: #1

Soil type	HSI
sand	1
loamy sand	1
loam	1
peat	1
other	0

Reference: #2

water level	HSI
shallow en temporal drying	1
wet	1
other	0

Reference: #2

salinity	HSI
very fresh	1
other	0

Reference: #1

water level fluctuation	HSI
hardly	1
other	0

Reference: #1

Uncertainty and validation

These dose-effect relations have not been validated.

Applicability

These dose effect relations have been based on habitat factors of plant communities belonging to this habitat type. Relations are not complete, as it is very difficult to identify distinguished relations for plant communities that belong to a successive development from open water to forest.

Example project

At present, there is no example of a project available.

References

1 Weeda, E.J., Schaminée, J.H.J., Van Duren, L.. Atlas van Plantengemeenschappen in Nederland. Deel 1. Wateren, moerassen en natte heiden. KNNV 2000.
2 http://www.minlnv.nl/natura2000