Red List habitat classification > RLC - Freshwater habitats > RLC2.5a Temperate temporary running watercourse

Temperate temporary running watercourse

Quick facts

Red List habitat type code RLC2.5a
Threat status
Europe Data Deficient
EU Data Deficient
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)


This habitat type includes temporary freshwater streams and rivers in the European temperate region. These water bodies are characterized by strong fluctuations in water level, which includes dry periods, alternating with long periods of running water. These fluctuations in water level are related to the level of the underlying water table and the amount of precipitation. In the United Kingdom the term ‘chalk streams’ is used to describe watercourses developing on chalk rock formations. This very soft and porous geological substrate acts as temporary reservoir. More than 80 % of the annual stream discharge originates from the aquifer in these chalk-based systems. The slow release of water from the aquifer provides a relatively stable hydrological regime despite the concentration of rainfalls in some seasons. Chalk streams can be subdivided into different hydrological categories. Only the winterbourne ones have a natural dry period each year and are considered part of the habitat C2.5a Temperate, temporary running waters. Chalk streams and rivers that never dry out are not included in this habitat. The seasonal cycle of wetting and drying results into characteristic plant communities that have adapted to these situation. The main channels are often dominated in spring by aquatic Ranunculus beds, consisting mainly of Ranunculus peltatus or R. penicillatus subsp. pseudofluitans. Note that Ranunculus fluitans is not typical of this habitat, because require more stable water level. Grasses and herbs are dominating the shores and accompanying marshes. Those include a number of annual species that appear in autumn after re-wetting of the shores. These temporary streams differ from Mediterranean temporary rivers mainly for the duration of the completely dry period (that is shorter) and for the absence of clearly Mediterranean floristic elements. If the dry period is prolonged and the hydrologic conditions very irregular these temporary streams could also scarcely vegetated.

England is usually considered to have the major part of properly defined ‘chalk streams’ of Europe. They are located in and down-stream of areas of outcropping chalk. It is unclear which other countries have similar streams, but surely temporary streams with similar hydrology they occur also in other karst areas of Europe and on substrates averagely permeable such as turbidite deposits rich in calcareous elements. In former times in United Kingdom, ‘chalk streams’ were connected to floodplains and wet meadows, representing systems with a high biodiversity and luxurious plant growth. Nowadays they are generally highly modified systems.

Indicators of good quality:

  • The periodical alternation of wet-and-dry regimes
  • The absence of heavy anthropogenic activities that can alter the hydrogeological system (e.g. water capitation and drainage, artificial shores for flood defence)
  • The absence of communities and species indicating an excessive nitrification or disturbance such as ruderal and exotic species
  • Water course connected to floodplains and wet meadows

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

Threat status

Synthesis of Red List assessment

The limited number and low quality of the data available have not allowed the use of any Red List criterion for the assessment. Only 15-20% (between 3 and 5) of the countries in which the habitat occurs were able to provide some quantitative or qualitative data. Most countries that were able to provide some kind of evaluation about the trend in quantity and quality stated that the habitat is declining and/or slightly damaged. The habitat has been assessed as Data Deficient (DD) due to the generalized lack of information and quantitative data.
Red List Category Red List Criteria
Data Deficient -
Red List Category Red List Criteria
Data Deficient -

Confidence in the assessment

Red List of habitat categories and criteria descriptions

Pressures and threats

  • Agriculture
    • Use of biocides, hormones and chemicals
    • Fertilisation
    • Irrigation
  • Mining, extraction of materials and energy production
    • Mining and quarrying
    • Sand and gravel extraction
  • Pollution
    • Pollution to surface waters (limnic, terrestrial, marine & brackish)
    • Pollution to groundwater (point sources and diffuse sources)
    • Soil pollution and solid waste (excluding discharges)
  • Natural System modifications
    • Human induced changes in hydraulic conditions
  • Climate change
    • Changes in abiotic conditions
    • Droughts and less precipitations
    • Flooding and rising precipitations
    • Changes in biotic conditions
    • Habitat shifting and alteration

Habitat restoration potential

The capacity of this habitat to recover naturally differs according to the type of damage that the habitat has undergone. If the damage influences the hydrology and morphology of the stream or its basin the recovery time can be very long or even impossible. If the damage is represented by pollution of superficial or even ground- water, the habitat can be restored in a relatively short time (10 years, or even less) through intervention and complete removal of the causes of pollution.

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

The conservation and management actions should include regulation of water abstraction, agricultural and industrial activities in the stream basin, fishing and extraction of send and gravel from the river bed. The restoration and improvement of the water quality and hydrological regime may be necessary in those cases where the habitat was damaged. The inclusion of some streams in protected areas could be useful to control and manage the water exploitation and other human activities such as fishing.

List of conservation and management needs

  • Measures related to agriculture and open habitats
    • Adapting crop production
  • Measures related to wetland, freshwater and coastal habitats
    • Restoring/Improving water quality
    • Restoring/Improving the hydrological regime
    • Managing water abstraction
  • Measures related to spatial planning
    • Establish protected areas/sites
    • Legal protection of habitats and species
    • Manage landscape features
  • Measures related to hunting, taking and fishing and species management
    • Regulation/Management of fishery in limnic systems
    • Specific single species or species group management measures
  • Measures related to urban areas, industry, energy and transport
    • Urban and industrial waste management


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)
Bulgaria Present unknown Decreasing Decreasing
France mainland Present unknown Unknown Unknown
Corsica Present unknown Unknown Unknown
Germany Present unknown Decreasing Decreasing
Italy mainland Present 111 Decreasing Decreasing
Luxembourg Uncertain unknown Unknown Unknown
Poland Uncertain unknown Unknown Unknown
Slovakia Present 0.01 Decreasing Decreasing
Slovenia Present 0.1 Decreasing Decreasing
Spain mainland Present unknown Decreasing Decreasing
Balearic Islands Present unknown Decreasing Decreasing
Canary Islands Present unknown Decreasing Decreasing
United Kingdom Present unknown Unknown Unknown
Northern Island Present unknown Unknown Unknown
Gibraltar Present unknown Unknown Unknown
Croatia Present 0.1 Unknown Unknown
Ireland Uncertain unknown Unknown Unknown
Romania Uncertain unknown Unknown Unknown
Austria Uncertain unknown Unknown Unknown
Estonia Uncertain unknown Unknown Unknown
Finland mainland Uncertain unknown Unknown Unknown
Greece (mainland and other islands) Uncertain unknown Unknown Unknown
Latvia Uncertain unknown Unknown Unknown
Lithuania Uncertain unknown Unknown Unknown
Portugal mainland Uncertain unknown 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)
Albania Uncertain unknown Unknown Unknown
Bosnia and Herzegovina Uncertain 1 Stable Increasing
Kosovo Uncertain unknown Unknown Unknown
Montenegro Uncertain unknown Unknown Unknown
Serbia Uncertain unknown Unknown Unknown
Kaliningrad Uncertain unknown Unknown Unknown
Former Yugoslavian Republic of Macedonia (FYROM) Uncertain unknown Unknown Unknown

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 77700 224 112 Only few countries were able to provide numerical data. Difficult to distinguish this habitat from others
EU28+ 224 113 Only few countries were able to provide numerical data. Difficult to distinguish this habitat from others
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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1050 Copenhagen K
Phone: +45 3336 7100