Section 4 - Technical guidance - Wetland
| Feature | Feature detail | Unit of measurement |
|---|---|---|
| W01 - Aquifer-fed naturally fluctuating water bodies - BAP habitat | - | hectares |
| W02 - Chalk rivers - BAP habitat | - | metres |
| W03 - Eutrophic standing waters - BAP habitat | - | hectares |
| W04 - Fens - BAP habitat | - | hectares |
| W05 - Lowland raised bogs - BAP habitat | - | hectares |
| W06 - Mesotrophic lakes - BAP habitat | - | hectares |
| W07 - Pond | Pond of high value | square metres |
| W08 - Reedbeds - BAP habitat | - | hectares |
See also
|
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W01 - Aquifer fed naturally fluctuating water bodies - BAP Habitat
- Only applies to fluctuating meres in Norfolk. Water depth varies: six metres in some cases to complete drying out for a period of time.
Condition assessment
- Concentric zonation of vegetation in these lakes is strikingly obvious, especially when they are in their dry phase. Water chickweed and common nettle are typical of the damp centre of Breckland mere basins, with a broad band of reed canary-grass at a slightly higher level.
- Pondweeds and stoneworts present during wet phases.
W02 - Chalk Rivers - BAP Habitat
- Chalk rivers have a characteristic plant community, often dominated in mid-channel by river water-crowfoot and water-starworts and along the edges by watercress and lesser water-parsnip.
- They have low banks which support a range of water-loving plants.
Condition assessment
If the site is a SSSI use the latest condition assessment from EN, otherwise leave the box blank.
W03 - Eutrophic standing waters - BAP habitat
- Standing waters greater than one hectare with plentiful plant nutrients.
- Often covered in dense algae in mid-summer.
- Beds are covered by dark anaerobic mud, rich in organic matter.
Condition assessment
- Marginal fringe of reedbed present.
- Algae are abundant in the water.
- Numerous species of invertebrate and fish are present.
- Bed covered by dark anaerobic mud.
W04 - Fens - BAP habitat
- Fens occur on soils that experience at least periodic waterlogging.
- They can encompass a wide range of plant communities on both peat and mineral soils and can include swamps, mires, springs and flushes.
- In the lowlands particularly, fens tend to be dominated by tall sedges, grasses and other tall herbs such as meadowsweet, yellow iris and common valerian.
- Fens often occur in association with other semi-natural habitats especially wet woodland, wet grassland and open water.
Notes
Species-poor fens in lowland heathland should be recorded as 'M03 - Lowland heathland - BAP habitat'.
This type of vegetation on unenclosed moorland should only be recorded as 'M07 - upland valley mires, springs and flushes'.
Common Reed often occurs in fens, however, vegetation with greater than 60% reed cover should be recorded as 'W08 - Reedbeds - BAP habitat'.
Condition assessment
- The water level and its management should result in either: surface water; or the ground being wet enough for a six-inch nail to be easily pushed in, for at least part of the year.
- Cover of undesirable species (docks, thistles, ragworts, Indian (Himalayan) Balsam) must be less than 5%.
- Cover of scrub must be less than 10%.
- The vegetation must (on average) be less than knee-high.
W05 - Lowland raised bog - BAP habitat
This is a rare habitat type.
Peatland vegetation dominated by bog mosses (Sphagnum), which develops mainly in cool humid lowland areas such as the head of estuaries, river flood-plains and in depressions where drainage is impeded.
The bog is usually slightly higher than the surrounding land.
Raised bog in lowland heathland should be recorded as M03 - Lowland heathland - BAP habitat.
See also 'M06 - Blanket bog - BAP habitat'.
Condition assessment
- Cover of undesirable species (docks, thistles, ragworts) must be less than 5%.
- Cover of scrub must be less than 10%.
- Cover of bog moss (Sphagnum) must be between 30% and 60%.
- Heathers and cotton grasses must be at least frequent.
W06 - Mesotrophic lakes - BAP habitat
- Lakes greater than one hectare with a narrow range of nutrients, such as inorganic nitrogen and phosphorus.
- They have a high diversity of floating, submerged and marginal aquatic plants.
Condition assessment
- Dragonflies, water beetles, stoneflies or mayflies present.
- At least ten different submerged and floating leaved plant species are present.
- Fringe of marginal vegetation including sedges.
W07 - Pond
Ponds up to one hectare in size including temporary ponds and scrapes.
If over a hectare it may be 'W03 - Eutrophic standing waters - BAP habitat' or 'W08 - Reedbeds - BAP habitat'.
Feature detail
Pond of high value: This includes sunny, shaded or temporary ponds which:
a) Contain at least 15 naturally occurring, floating, submerged and/or marginal plants
and/or
b) support high value species of plant or animal.
Note
High value species includes BAP species and species that have been recognised as of national or local significance. Record the species separately (see species features pages 98-100) or record in the notes column.
Condition assessment
- No obvious signs of pollution or water supply of inappropriate quality.
- Absence of damaging alien plants or animal species.
W08 - Reedbeds - BAP habitat
- Reedbeds are wetlands dominated by stands of common reed.
- The water table is at or above ground level for most of the year.
- They tend to incorporate areas of open water and ditches, and small areas of wet grassland and wet woodland may be associated with them.
Condition assessment
- Cover of scrub within the reedbed must be less than 10%.
- The vegetation must include at least 60% reeds.
- Surface water is present over at least part of the reedbed for most of the year.
- Cover of undesirable species (docks, thistles, ragworts, Indian (Himalayan) balsam) must be less than 5%.
Page last modified:
19 May, 2005
Page published: 3 March, 2005