Red List habitat classification > RLE - Grasslands > RLE1.1b Cryptogam- and annual-dominated vegetation on siliceous rock outcrops

Cryptogam- and annual-dominated vegetation on siliceous rock outcrops

Quick facts

Red List habitat type code RLE1.1b
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)

Summary

These open pioneer grasslands occur on shallow soils (Leptosols) at rock outcrops, on eroded slopes, or in disturbed patches within dry or mesic grasslands. Stands are usually of limited extent, in many cases occupying just a few square metres. This vegetation is dominated by vernal therophytes of the genera Cerastium, Myosotis, Veronica and others and succulent plants of the genera Sedum or Sempervivum (inclusive Jovibarba). Hemicryptophytes are also common, especially the narrow-leaved tussock-forming species of Festuca and several xerophilous Poa species, but they are not the dominant component of this vegetation, except for some short-growing species such as Scleranthus perennis. Geophytes such as Gagea sp. pl. also occur in places. The richness of therophytes and geophytes increases when moving from northern and western to southeastern Europe. Bryophytes and lichens are also common and they can attain a very high cover in some places. Mosses are represented for example by Ceratodon purpureus, Polytrichum piliferum and Syntrichia ruralis agg., lichens by Cetraria aculeata, Cladonia sp. pl. and Xanthoparmelia sp. pl.

Shallow soils supporting this vegetation are well drained and dry out quickly, especially during summer periods of warm weather. Therefore vegetation has its phenological optimum in spring when moisture is still available due to lower evaporation rates. Most therophytes complete their life cycle within a short period of a few weeks prior to the peak of the seasonal development of hemicryptophytes, which helps them avoid competition for light. In contrast, most succulents are perennial and adapted to enduring summer drought period. However, they are more sensitive to disturbance, therefore more disturbed sites tend to contain more therophytes and less disturbed sites more succulents.

This vegetation is distributed throughout temperate and boreal Europe, but it is rarely found in extensive stands. It occurs across a broad altitudinal range from the lowlands to the subalpine belt. The type corresponds to the phytosociological order Sedo-Scleranthetalia, including the Sedo-Poetalia glaucae, which is by some authors separated as an order that occurs from the middle boreal to the arctic zone. Phytosociological literature distinguishes several alliances confined to different European regions, which are geographical vicariants with distinct species composition. A specific subtype of this habitat is found in the supratemperate, very humid belt of Madeira (over 1400 m a.s.l.), where Thymus micans dominates open pioneer communities on shallow soils and rocks, derived from hard volcanic substrate. Another specific subtype occurs on and around acidic outcrops in middle and northern Fennoscandia and Iceland (the Veronico-Poion glaucae).

Indicators of good quality:

These grasslands are confined to stressed or disturbed sites. Due to their small spatial extent, individual stands can be entirely destroyed, but they can regenerate if suitable conditions return. Sites on the rock outcrops near lookout points can be negatively affected through frequent trampling by tourists. On the other hand, disturbance-dependent stands occurring in patches among closed grasslands may become overgrown by tall perennial species if disturbance (e.g. grazing) ceases. Therophytes typical of this vegetation can also occur in human-made habitats such as roadsides, railway banks or quarries, where they form communities with ruderal and nutrient demanding species; such sites are not included in this habitat type and are of lower conservation interest.

The following characteristics can be considered as indicators of good quality:

·      Long-term habitat stability

·      High species richness of therophytes and succulents

·      Occurrence of rare species

·      Dependence on naturally stressful conditions or natural disturbance rather than human-induced disturbance

·      Absence of tall, nutrient-demanding and ruderal species

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

Threat status

Synthesis of Red List assessment

Based on both the short-term reduction in quantity of 37% and the long-term reduction of 51%, the habitat is assessed as vulnerable (VU) in both EU28 and EU28+.
EU
Red List Category Red List Criteria
Vulnerable A1, A3
Europe
Red List Category Red List Criteria
Vulnerable A1, A3

Confidence in the assessment

medium
Red List of habitat categories and criteria descriptions

Pressures and threats

  • Agriculture
    • Abandonment of pastoral systems, lack of grazing
  • Mining, extraction of materials and energy production
    • Mining and quarrying
  • Urbanisation, residential and commercial development
    • Urbanised areas, human habitation
  • Pollution
    • Nitrogen-input
  • Natural biotic and abiotic processes (without catastrophes)
    • Biocenotic evolution, succession

Habitat restoration potential

Degraded semi-natural (e.g. in former pasture systems) and anthropogenic stands (e.g. wall tops; railway gravel) can be restored by re-installing the former grazing system and/or cutting down woody encroachment inside the habitat (and in its surrounding, if it throws shadow on the site).
Natural and and semi-natural sites that have been degraded by quarrying or leisure activities can recover themselves when the negative impact has stopped, but this will take considerable time.

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

Generally, continuation of low-intensity grazing is the recommended measure. However, the majority of stands is rather stable also without management.

List of conservation and management needs

  • No measures
    • No measures needed for the conservation of the habitat/species
  • Measures related to agriculture and open habitats
    • Maintaining grasslands and other open habitats

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)
Austria Present 10 Decreasing Decreasing
Bulgaria Present 88 Decreasing Stable
Croatia Uncertain Unknown Unknown Unknown
Czech Republic Present 19 Decreasing Decreasing
Finland mainland Present 5 Decreasing Decreasing
Aland Islands Uncertain 5 Decreasing Decreasing
France mainland Present 125 Decreasing Decreasing
Corsica Uncertain 125 Decreasing Decreasing
Germany Present 7 Decreasing Decreasing
Greece (mainland and other islands) Uncertain Unknown Unknown Unknown
Hungary Uncertain Unknown Unknown Unknown
Ireland Present Unknown Unknown Unknown
Italy mainland Present 141 Decreasing Stable
Sardinia Uncertain 141 Decreasing Stable
Sicily Uncertain 141 Decreasing Stable
Lithuania Present 2 Decreasing Decreasing
Luxembourg Uncertain Unknown Unknown Unknown
Poland Present Unknown Stable Decreasing
Portugal mainland Present 0.34 Unknown Decreasing
Romania Present 0.2 Stable Stable
Slovakia Present 0.45 Decreasing Stable
Slovenia Present 0.05 Stable Stable
Spain mainland Present 647 Unknown Stable
Balearic Islands Uncertain 647 Unknown Stable
Sweden Present 80 Decreasing Decreasing
United Kingdom Present 120 Decreasing Unknown
Northern Island Uncertain 120 Decreasing Unknown
Portugal Azores Uncertain 0.34 Unknown Decreasing
Madeira Present 0.34 Unknown 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)
Albania Uncertain Unknown Unknown Unknown
Andorra Uncertain Unknown Unknown Unknown
Bosnia and Herzegovina Present 5 Decreasing Decreasing
Faroe Islands Uncertain Unknown Unknown Unknown
Guernsey Uncertain Unknown Unknown Unknown
Iceland Present Unknown Unknown Unknown
Isle of Man Uncertain Unknown Unknown Unknown
Jersey Uncertain Unknown Unknown Unknown
Kosovo Present Unknown Decreasing Stable
Liechtestein Uncertain Unknown Unknown Unknown
Former Yugoslavian Republic of Macedonia (FYROM) Uncertain Unknown Unknown Unknown
Monaco Uncertain Unknown Unknown Unknown
Montenegro Uncertain Unknown Unknown Unknown
Norway Mainland Present Unknown Unknown Unknown
Svalbard Uncertain Unknown Unknown Unknown
Jan Mayen Uncertain Unknown Unknown Unknown
San Marino Uncertain Unknown Unknown Unknown
Serbia Uncertain Unknown Unknown Unknown
Switzerland Present 5 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 10876150 5568 650
EU28+ 8319 800
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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