Madeiran oromediterranean siliceous dry grassland

This habitat consists of perennial cespitose grasslands of oromediterranean, humid to ultrahyperhumid bioclimates, in the summit of mountains of Madeira Island, to which this vegetation is strictly endemic. Such communities occur at altitudes over 1,500 m Asl, either in earthy rock crevices (chasmophytic) or over horizontal platforms along hillsides with shallow andosols, on silicate volcanic substrata (either hardrock or pyroclast). The physiognomy of these communities varies from dense mat-like, more or less continuous in platforms, to discontinuous on rock outcrops following crevices; it´s height is normally between 0.2 and 0.4 m. Dominant species are mostly madeiran endemic grasses: Parafestuca albida (= Koeleria albida), Deschampsia maderensis, Festuca jubata, Anthoxanthum maderense, Agrostis obtusissima and Holcus pintodasilvae; notheworthy madeiran endemics having their optima in this habitat are: Armeria maderensis, Anthyllis lemmaniana, Crepis andryaloides, Orchis scopulorum, Micromeria varia subsp. thymoides var. cacuminicolae, Rumex bucephalophorus subsp. fruticescens.

This vegetation occupies azonal permanent habitats in a mosaic with tree-heath forests of Madeira (Polysticho falcinelli-Ericion canariensis- G2.7 =Polysticho-Ericion arboreae) and mat-forming mountain low heath communities of Erica maderensis (Argyranthemo montani-Ericetum maderensis, Bystropogono punctati-Telinion maderensis –G2.7). Side contacts with succulent semi-deciduous rosette Crassulaceae comophyte (i.e. on the surface of rock) communities (Sinapidendro angustifolii-Aeonion glandulosi – F8.2) enrich the madeiran grasslands with many other endemics (see F8.2- Madeiran xerophytic scrub). Other common contacts are with Thymus micans communities (E1.Ad).

As the summit of Madeira´s mountains was, until recently, grazed mostly by domestic goats, the coenotic extreme of the community in platforms is thought to be quite rare, being the rocky coenotical extreme the dominant case. Platforms if permanently grazed normally had nitrogen-prone grasslands dominated by Agrostis castellana / Holcus sp. pl. With withdrawal of goat grazing the platforms with shallow andosols were gradually colonized, in recent years, by this habitat's community where the habitat optimum seems to be. Thus, due to grazing withdrawal the actual area of the community is bigger than it was ten years ago. Although in shallower platforms and rock outcrops the community seems to be of a permanent type (a permasigmetum in the sense of S. Rivas-Martínez) and kept by regular gravitational disturbance, in deeper more stable soils ecological succession may lead to substitution of grasslands by woody types.

Indicators of quality:

The habitat contains a set of endemics with high constancy and fidelity that are observed in most well-preserved situations. Nevertheless, poorer basal communities dominated by few of the grasses can be found. These have lower floristical quality, but, in turn can develop into fully coenotically saturated versions. In general, the greater the diversity of the above cited flora is found and less of generalist Mediterranean and Madeiran-Canarian grasses or semi-nitrogen-prone grasses (e.g. Bromus sp. pl.) are found, the better the habitat quality is (e.g. Dactylis smithii subsp. hylodes, Agrostis castellana).

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats