Cryptogam- and annual-dominated vegetation on calcareous and ultramafic rock outcrops

This habitat includes low-grown, open herbaceous communities on very shallow, skeletal soils over limestone, dolomite, gypsum, serpentine or other base-rich bedrock types. Short-lived vernal therophytes and succulents are the dominant life forms among the vascular plants. The therophyte synusia is often rich in species, however, it is subject to considerable inter-annual dynamics in total abundance and species composition, which depends on specific weather conditions of each year. Typical therophytes include those of the genera Alyssum, Androsace, Arabis, Arenaria, Cerastium, Erophila, Thlaspi and Veronica. Succulents are represented by various species of Sedum and Sempervivum (including Jovibarba). Geophytes such as Allium are also typical. Perennial grasses and forbs are regularly present in this vegetation, but usually with a low cover.

This habitat is one of the few types in Europe, where non-vascular plants typically reach similar or higher cover and often also higher small-scale species richness than the vascular plants. There are many medium-sized to tiny cushions or lawns of acrocarpous mosses, mainly from the family Pottiaceae. Lichens are represented by several larger lobate or fruticose species, but mainly by soil-covering crusts. These crustose species are often colourful, like Fulgensia spp. (yellow), Psora decipiens (red), Toninia sedifolia (bluish) and Squamarina lentigera (bright white) and form the so-called coloured lichen synusia.

This habitat usually occurs in small patches on rock outcrops or in slightly disturbed places within calcareous grasslands. Disturbance can be by soil erosion on outcrops and steep slopes, by grazing or trampling. The soils are usually very shallow Lithic, Skeletic, Rendzic, Calcaric or Dolomitic Leptosols, developed on various types of limestone, dolomite or gypsum. In some places, especially on the Balkan Peninsula, this vegetation develops also on ultramafic bedrock (serpentines), which are also base-rich, but with an increased amount of Mg²⁺ rather than Ca²⁺ cations.

This habitat is distributed from the submediterranean to the hemiboreal zones of Europe. In southern Europe it occurs mainly at higher altitudes, while similar sites at lower altitudes support annual vegetation with different species composition, dominated by Mediterranean annual species. Compared to the rocky grasslands of type E1.1g, which typically cover larger areas on slopes, the stands of E1.1d normally grow in more or less plain patches where the erosion is reduced and thus tiny annuals and cryptogams can survive. While such situations in most parts of Europe occur only as small patches within dry grasslands, the so-called alvars in the hemiboreal zone of Europe (mainly the Swedish islands of Öland and Gotland as well as Western Estonia) display this habitat as landscape-dominating feature, partly extending over many square kilometres as in the Great Alvar of Öland. Here, pre-Cambrian limestone flatrocks that are covered only partly and very thin with fine soil, which is subject to strong frost action in winter, create an extraordinary habitat, rich in specialised species, including even some endemic taxa.

While human land use has slightly increased the spatial extent of this habitat type (through clearing forest and creating artificial rocks, such as wall tops), the majority of stands of E1.1d are natural.

 Indicators of quality:

These grasslands occur at sites disturbed by natural erosion, grazing, or due to human impact such as trampling. Although very frequent or intense disturbance may be detrimental, especially if coupled with nutrient enrichment, slight disturbance is positive because it reduces overgrowing by competitively stronger grasses and herbs. Some occurrences of this habitat, especially those occurring outside rock outcrops or steep slopes, would decline in the absence of disturbance.

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

·      Long-term habitat stability

·      High species richness

·      Occurrence of rare species

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

·      Absence of tall, nutrient-demanding, ruderal and alien species

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats