Rivers & Streams (definition)

Durham Lowland Priority Habitats
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Rivers and Streams Habitat Definition

Rivers and streams are naturally dynamic habitats with a constant or seasonal flow of water. In their unmodified state rivers are dynamic features, which interact with their floodplains enabling a range of wetland habitats to develop such as grazing marsh, wet woodland and fen habitats including reedbed. Both shingle beds and eroding river banks support a range of specialised invertebrates, including very rare beetles. Small streams and ditches are important, particularly as corridors for mobile species such as the otter and kingfisher.

Identification & Mapping

This habitat definition encompasses all natural and near-natural running water systems including rivers, streams, ditches and their associated riparian habitat that meet any of the following criteria:

  1. Riverine water bodies of good or high hydromorphological/ecological status (as defined by the Water Frameword Directive)
  2. Headwaters (defined as a watercourse within 2.5km of its furthest source as marked with a blue line on OS maps at 1:50,000 scale, excluding headwater which have been significantly altered from their natural state)
  3. Active shingle rivers
  4. Contains records of at least 1 species from the following list (which are BAP priority species strongly dependent on river quality):
    Common sturgeon
    Spined loach

    Smelt
    River jelly lichen
    White clawed-crayfish
    Pale pin-palp
    River-shore crane fly  
    Freshwater pearl mussel
    Northern february red stonefly
    Floating water plantain
    Reed bunting (only when recorded breeding near a river)
  5. Contains records of 6 or more species from the following list (widespread BAP priority species that are less dependent on river quality):
    European eel
    Bullhead
    Atlantic salmon
    Brown/sea trout
    River lamprey
    Brook lamprey
    Sea lamprey
    Northern yellow splinter
    Water vole
    Otter
    Soprano pipistrelle
    Tubular water-dropwort
    Greater water parsnip
    Marsh stitchwort

 

When mapping the extent of this habitat, the reaches should only extend to the top of adjacent banks. Areas of other BAP priority habitats that are adjoining this habitat, such as lowland fen or wet woodland, although part of the river system, should be mapped and recorded separately. The exception to this, are ponds which have been created as a result of river dynamics, e.g. oxbows.

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