Red List habitat classification > RLG - Forests > RLG1.4 Broadleaved swamp woodland on non-acid peat

Broadleaved swamp woodland on non-acid peat

Quick facts

Red List habitat type code RLG1.4
Threat status
Europe Vulnerable
EU Vulnerable
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


These are true swamp woodlands on non-acid peat or hydromorphic soils with a high content of organic matter occurring mainly in lowland fens where the water-table is constantly at ground level or seasonally above it, for example where sites are inundated by spring snow-melt or rain-fed flooding. However, in contrast to the woodlands of mature floodplains included in G1.2 and G1.3, there is no regular deposition of allochthonous sediments, so enrichment and terrestrialisation typically do not occur here though intermediate habitats can be found in wetter river valleys. There is characteristically a well-developed tree canopy in which, throughout most of the nemoral zone, Alnus glutinosa is the usual dominant, often with a naturally multi-stemmed growth form, Quercus robur replacing it locally in the more Continental east and Populus tremula in the Boreal zone. On thin peats in Boreal swamps of the Finnish coast and archipelago and in regions in central Europe where Alnus glutinosa is missing, Alnus incana can replace A. glutinosa in this swamp woodland. Also the dense Alnus barbata forests on swamps on coastal alluvial plains around the Black Sea belong here. Betula pubescens is a common associate but never dominates. Shrubby willows such as Salix aurita, Salix cinerea and Salix pentandra can occur in an understorey, along with other smaller woody species listed below, but they do not dominate here. Shrubby vegetation (with or without occasional trees) developed in similar situations are placed in F9.2 and F9.3 Riparian scrubs. In the field layer, large Carex spp. are a consistent and sometimes prominent feature, with C. elongata typical through much of central Europe, C. laevigata and C. paniculata replacing it towards the Atlantic zone. The associated flora throughout can be rich with large graminoids, tall herbs and sprawlers, including many typical fen species, and a carpet of bryophytes tolerant of more shady wet habitats. In Boreal and Euxinic stands, the associated flora has some distinctive herbs. In other stands, alders and huge sedge tussocks can dominate in much more species-poor swamp with much bare peat and open water.

Indicators of quality:

  • No forest exploitation or only very limited signs of forestry
  • Intact natural hydrology: maintenance of high groundwater table and no signs of drying of the peat or water-logged soil
  • Typical structure and composition of canopy: dominance must always ultimately lie with vigorously growing trees rather than the associated shrubs
  • Presence of old trees and a variety of dead wood (lying and standing) and the associated flora, fauna and fungi
  • Presence of natural disturbance such as treefall openings with natural regeneration
  • Structural diversity/complexity with (semi)natural age structure or completeness of layers
  • Regional variation in the associated flora of this essentially azonal habitat is low but such distinctive typical flora and fauna species as are characteristic should persist.
  • Absence of non-native tree species and absence of invasive aliens in all layers (fauna and flora),
  • Absence of species indicative of drying of the peat or the wet soil conditions or of excessive eutrophication and no signs of pollution

Characteristic species
For full habitat description, please download the habitat factsheet.

Threat status

Synthesis of Red List assessment

The habitat is Vulnerable, because of a reduction in quantity of 34 % (EUR28) and an assumed reduction of >30% in EUR28+ (for EUR28+ a reassessment with more data is recommended). Furthermore an intermediate reduction in quality over almost 2/3 of its area supports the assessment Vulnerable under criterion C/D1. Because of large EOO and AOO all other criteria are least concern. Assessment of long-term historic trends was not possible due to data deficiencies. With a strict and more consistent application of quality indicators an even larger area would be at least slightly affected.
Red List Category Red List Criteria
Vulnerable A1
Red List Category Red List Criteria
Vulnerable A1

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Sylviculture, forestry
    • Forest replanting (non native trees)
    • Removal of dead and dying trees
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
  • Invasive, other problematic species and genes
    • Invasive non-native species
    • Problematic native species
  • Natural System modifications
    • Human induced changes in hydraulic conditions
    • Modification of hydrographic functioning, general
    • Modification of standing water bodies
    • Water abstractions from surface waters
    • Water abstractions from groundwater
  • Natural biotic and abiotic processes (without catastrophes)
    • Introduction of disease (microbial pathogens)
  • Climate change
    • Changes in abiotic conditions

Habitat restoration potential

Natural full recovery of the habitat usually needs time-spans of over 200 years. While the tree species can be planted, the full set of characteristic species includes many saproxylic intertebrates and fungi which need a historic habitat continuity, old and dead trees in a late development stage of forests. Semi-aquatic characteristic invertebrates can partially recolonize after interventions, provided the necessary habitat structures have developed. Some of the characteristic plant species such as Carex spp. have a long term seedbank and may redevelop if the hydrology is restored. Through intervention a partial recovery is possible in > 50 years, for the full set of saproxylic species also >200 years are needed.

Trends in extent

Average current trend in quantity

Decreasing Decreasing
EU28 EU28+

Trends in quality

Average current trend in quality

Decreasing Decreasing
EU28 EU28+

Conservation and management needs

Restoring the natural hydrology (removal of drainage, stopping water abstractions) and reducing all kinds of pollution and eutrophication sources are vital to reducing the pressures and threats. In addition, restoring coniferous plantations to natural tree composition and allowing for more dead and dying trees in managed forests are important to maintain the full set of characteristic species. Regionally specific measures for reducing the impact of non-native species will be necessary.

List of conservation and management needs

  • Measures related to forests and wooded habitats
    • Restoring/Improving forest habitats
    • Adapt forest management
  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving the hydrological regime
    • Managing water abstraction
  • Measures related to spatial planning
    • Establish protected areas/sites
    • Establishing wilderness areas/allowing succession
  • Measures related to urban areas, industry, energy and transport
    • Specific management of traffic and energy transport systems


For each habitat a distribution map was produced from a wide variety of sources indicating known and potential occurrences of the habitat in 10x10 km grids within Europe. Occurrences in grid cells were given in two classes: actual distribution from relatively reliable sources (surveys, expert knowledge), and potential distribution based on models or less reliable indicators. Please download the fact sheet to see the map.

Geographic occurrence and trends

EU28 Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Austria Present unknown Decreasing Decreasing
Belgium Present 40 Decreasing Stable
Bulgaria Present 0.5 Decreasing Decreasing
Croatia Present Oct-50 Decreasing Decreasing
Czech Republic Present 39 Decreasing Decreasing
Denmark Uncertain unknown Unknown Unknown
Estonia Present 400 Unknown Decreasing
Finland mainland Present unknown Decreasing Decreasing
Aland Islands Uncertain unknown Decreasing Decreasing
France mainland Present - -
Germany Present <1000 Decreasing Decreasing
Latvia Present 225 - -
Lithuania Present 1800 Decreasing Increasing
Luxembourg Uncertain unknown Unknown Unknown
Netherlands Present 37 Stable Increasing
Portugal mainland Present 32 Unknown Decreasing
Romania Present 50 Decreasing Decreasing
Slovakia Present 1.5 Unknown Decreasing
Slovenia Present 117 Decreasing Decreasing
United Kingdom Present 70 Decreasing Unknown
Northern Island Present 70 Decreasing Unknown
Ireland Present 9.2 Increasing Decreasing
Hungary Uncertain ujnknown Unknown Unknown
Italy mainland Present unknown Unknown Unknown
Poland Present 245 Decreasing Decreasing
Spain mainland Uncertain Unknown Unknown
Sweden Uncertain unknown Unknown Unknown
EU28 + Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)
Bosnia and Herzegovina Present ca. Decreasing Decreasing
Norway Mainland Present 3780 Unknown Decreasing
Serbia Present Unknown Unknown
Switzerland Present 10 Decreasing Decreasing

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 4237200 2006 5400
EU28+ 2014 9600
AOO = the area occupied by a habitat measured in number of 10x10 km grid cells.
EOO = the area (km2) of the envelope around all occurrences of a habitat (calculated by a minimum convex polygon).

Characteristic species

Not available

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

Not available
European Environment Agency (EEA)
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