Red List habitat classification > RLH - Sparsely vegetated habitats > RLH2.6b Western Mediterranean base-rich scree

Western Mediterranean base-rich scree

Quick facts

Red List habitat type code RLH2.6b
Threat status
Europe Least Concern
EU Least Concern
Relation to
Source European Red List habitat factsheet
European Red List of habitats reports
European Red List of habitats (Excel table)

Summary

This is a calcareous and ultrabasic scree, constituted by boulders, rock debris and riverine gravel of the western Mediterranean, from lowlands through to the high mountains. It is composed by rock types that are sedimentary and metamorphic limestones and dolomites, further serpentinite and other ultramafic as well as silica-poor igneous volcanic rock such as basalt. Epilithic lichens and bryophytes may be very diverse, particularly in the mountains, where they are mostly found in crevices and other shady and humid microsites of immobile boulders. The vascular plant vegetation of western Mediterranean base-rich screes consists mainly of hemicryptophytes and chamaephytes adapted to the mechanical disturbance caused by mobile screes, shortages in water supply and lack of fine-grained soil. Many plants are disturbance-resilient and capable of regeneration even after being buried by moving stones. Prostrate stems, stolons, radicants, extensive root systems, storage tubers and rhizomes are common traits in the plants that are present in this habitat. Scree creeping, passive moving with mobile screes, and accumulation of scree through resilient tussocks and root stocks, thereby controlling erosion, are characteristic growth form functional strategies in Mediterranean screes. Species-rich genera of vascular plants are, among others, Campanula, Iberis, Linaria and Scrophularia. The species composition in the high mountains is particularly variable and includes many regional endemic taxa. Several phytosociological alliances restricted to subalpine and alpine levels of mountain ranges in the Iberian and Apennine Peninsulas or to the larger islands have been described. They reflect phytogeographical patterns of isolation and centers of speciation. Lowland scree and gravel vegetation is in comparison more uniform in the western Mediterranean. Most plant communities belong to the extremely variable class of Thlaspietea rotundifolii. Local habitat variation reflects differences in slope and substrate mobility, rock size and mineral composition, microclimate, aspect and solar radiation, humidity and precipitation.

Mediterranean base-rich screes cover extensive areas in the high mountains. In the lowlands and foothills, by contrast, they may be rare. Gravel banks occur along permanent or temporary streams. Western Mediterranean base-rich scree habitats occur from the Iberian Peninsula through southern France to the Apennines (Italy), on the Balearic Islands, Corsica, Sardinia, Sicily, and on many of the smaller islands and archipelagos of the Tyrrhenian Sea, such as the Tuscan, the Aegadian and the Aeolian, and further in the Mediterranean domain of northwest Africa (Morocco, Algeria and Tunisia).

Indicators of quality:

The dynamics of scree and gravel habitats depend on the natural constant supply of rock debris and riverine materials. When there is no supply from rock source areas above, the habitat and its vegetation will be subject to succession and gradually change in character towards grasslands, shrublands or woodlands. High-mountain screes in the western Mediterranean, underlying natural dynamics, are normally little or not affected by human impact. In contrast, riverine gravel fills in the lowlands, with their rivers, have commonly been subjected to quarrying, hydrological control or other drastic changes of the river regime. Human-made screes such as mining heaps may provide important and valuable secondary habitats, especially after long periods of abandonment. They should be considered and preserved when their quality is good, especially when primary scree habitats are absent in a wider area. The habitat quality must be assessed by taking into account the regional species pool. Scree and boulder specialists, with many endemics and relict plants among them, are useful indicators of good habitat quality.

The following characteristics may be used as indicators of favorable habitat quality:

  • Occurrence of rare and phyto-geographically significant plants
  • Presence of sizable areas of scree and gravel with adequate and ongoing supply of rock material through cliff, stream and river dynamics, and with local differences in slope, moisture, aspect, substrate mobility, and grain size
  • Contact with natural habitats such as cliffs, high-mountain pioneer grasslands and plant cushion vegetation, or riverine scrubs and woodlands
  • Absence of gravel quarrying and mining
  • Absence of hydrological and traffic constructions affecting the river regime

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

Threat status

Synthesis of Red List assessment

The habitat is assessed as Least Concern (LC) in view of its stable trend, since a reduction of less than 3% has occurred over the last 50 years. The quality of this habitat has decreased over the last 50 years, but it is not declining fast enough to qualify for a threatened category.
EU
Red List Category Red List Criteria
Least Concern -
Europe
Red List Category Red List Criteria
Least Concern -

Confidence in the assessment

medium
Red List of habitat categories and criteria descriptions

Pressures and threats

  • Mining, extraction of materials and energy production
    • Mining and quarrying
  • Transportation and service corridors
    • Roads, paths and railroads
    • Paths, tracks, cycling tracks
  • Human intrusions and disturbances
    • Outdoor sports and leisure activities, recreational activities
    • Mountaineering, rock climbing, speleology
    • Skiing, off-piste

Habitat restoration potential

Recovery of this habitat is possible provided that the natural geo-morphological processes are not hampered and that undamaged sites occur nearby. There is no further information available on this issue.

Trends in extent

Average current trend in quantity

Stable Stable
EU28 EU28+

Trends in quality

Average current trend in quality

Stable Stable
EU28 EU28+

Conservation and management needs

The best management practice for this highly natural habitat is to leave it simply untouched, thus avoiding any human interference with its natural processes. Natural succession, if any, cannot be seen as a threat. An increase on public awareness about the biological relevance of these apparently inhospitable and sterile environments is recommended.

List of conservation and management needs

  • Measures related to spatial planning
    • Establish protected areas/sites
    • Manage landscape features

Distribution

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)
France mainland Present 131 Decreasing Decreasing
Italy mainland Present 144 Decreasing Stable
Sardinia Present 144 Decreasing Stable
Sicily Present 144 Decreasing Stable
Portugal mainland Present 5,4 Unknown Increasing
Spain mainland Present 72 Stable Stable
Balearic Islands Present 72 Stable Stable
Corsica Present 131 Decreasing Decreasing
EU28 + Present or presence uncertain Current area of habitat (Km2) Recent trend in quantity (last 50 years) Recent trend in quality (last 50 years)

Extent of Occurrence, Area of Occupancy and habitat area

Extent of Occurrence (EOO) (Km2) Area of Occupancy (AOO) Current estimated Total Area Comment
EU28 1548150 351 352
EU28+ 351 352
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

The full list of characteristic species and genus are available above from the Summary. The species available in the EUNIS database are shown here.
Ferns Cystopteris montana
Ferns Gymnocarpium robertianum
Ferns Polystichum lonchitis
Flowering Plants Achnatherum calamagrostis
Flowering Plants Adonis distorta
Flowering Plants Allium palentinum
Flowering Plants Androsace ciliata
Flowering Plants Andryala ragusina
Flowering Plants Arabis alpina subsp. alpina
Flowering Plants Arenaria bertolonii
Flowering Plants Biscutella valentina
Flowering Plants Bupleurum ranunculoides subsp. ranunculoides
Flowering Plants Calamagrostis pseudophragmites
Flowering Plants Carduus carlinoides
Flowering Plants Coincya monensis subsp. cheiranthos
Flowering Plants Conopodium thalictrifolium
Flowering Plants Crambe filiformis
Flowering Plants Echium albicans
Flowering Plants Eryngium glaciale
Flowering Plants Festuca glacialis
Flowering Plants Galeopsis angustifolia
Flowering Plants Gouffeia arenarioides
Flowering Plants Hypochaeris robertia
Flowering Plants Jurinea fontqueri
Flowering Plants Laserpitium gallicum
Flowering Plants Minuartia cerastiifolia
Flowering Plants Myosotis alpestris
Flowering Plants Plantago monosperma
Flowering Plants Platycapnos saxicola
Flowering Plants Poa balbisii
Flowering Plants Ptilostemon niveus
Flowering Plants Ptychotis saxifraga
Flowering Plants Rumex scutatus
Flowering Plants Salix breviserrata
Flowering Plants Scrophularia canina
Flowering Plants Scrophularia sciophila
Flowering Plants Senecio pyrenaicus
Flowering Plants Spergula viscosa
Flowering Plants Tolpis staticifolia
Flowering Plants Trisetum distichophyllum
Flowering Plants Verbascum conocarpum
Flowering Plants Vincetoxicum hirundinaria subsp. lusitanicum
Species scientific name English common name Species group
Cystopteris montana Ferns
Gymnocarpium robertianum Ferns
Polystichum lonchitis Ferns
Achnatherum calamagrostis Flowering Plants
Adonis distorta Flowering Plants
Allium palentinum Flowering Plants
Androsace ciliata Flowering Plants
Andryala ragusina Flowering Plants
Arabis alpina subsp. alpina Flowering Plants
Arenaria bertolonii Flowering Plants
Biscutella valentina Flowering Plants
Bupleurum ranunculoides subsp. ranunculoides Flowering Plants
Calamagrostis pseudophragmites Flowering Plants
Carduus carlinoides Flowering Plants
Coincya monensis subsp. cheiranthos Flowering Plants
Conopodium thalictrifolium Flowering Plants
Crambe filiformis Flowering Plants
Echium albicans Flowering Plants
Eryngium glaciale Flowering Plants
Festuca glacialis Flowering Plants
Galeopsis angustifolia Flowering Plants
Gouffeia arenarioides Flowering Plants
Hypochaeris robertia Flowering Plants
Jurinea fontqueri Flowering Plants
Laserpitium gallicum Flowering Plants
Minuartia cerastiifolia Flowering Plants
Myosotis alpestris Flowering Plants
Plantago monosperma Flowering Plants
Platycapnos saxicola Flowering Plants
Poa balbisii Flowering Plants
Ptilostemon niveus Flowering Plants
Ptychotis saxifraga Flowering Plants
Rumex scutatus Flowering Plants
Salix breviserrata Flowering Plants
Scrophularia canina Flowering Plants
Scrophularia sciophila Flowering Plants
Senecio pyrenaicus Flowering Plants
Spergula viscosa Flowering Plants
Tolpis staticifolia Flowering Plants
Trisetum distichophyllum Flowering Plants
Verbascum conocarpum Flowering Plants
Vincetoxicum hirundinaria subsp. lusitanicum Flowering Plants

Vegetation types

Relation to vegetation types (syntaxa)

Not available

Other classifications

This habitat may be equivalent to, or broather than, or narrower than the habitats or ecosystems in the following typologies.
Classification Code Habitat type name Relationship type
EUNIS Habitat Classification 200711 H2.6 Calcareous and ultra-basic screes of warm exposures narrower
European Environment Agency (EEA)
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