Iberian oromediterranean siliceous dry grassland

Dwarf grasslands growing in alpine (crioro) and upper subalpine (oro) environment at elevations above 1900 m in siliceous mountains in Mediterranean Iberian Peninsula, from the Cantabrian range in the NW to Sierra Nevada in the SE. Conditions are extreme in such altitudes, and include low temperatures, a short growing season in which solar irradiation is very high and rainfall can be low, combined with a high wind exposure. Strong wind sweeps the snow preventing from being accumulated. The removal of the protective snow layer in winter exacerbates drought by enhancing evaporation and also entails an important abrasion and mechanical pressure. Due to the extreme cold and dryness, those grasslands have been qualified as psychro-xerophilous. They occupy crests and slopes in which snow cover is shallow, avoiding depressions where it accumulates. Phenomena of cryoturbation and solifluxion are common in the soils, which are leptosols, lithosols or distric cambisols without histic, gleic and hydromorphic properties. The plants are dwarf or prostrated, with hard tissues to endure wind abrasion and drought. The grasses, particularly the Festuca species, have hard leaves with sclerenchyma bundles that give way to a low palatable or even indigestive pasture (revientabarrigas). Cover can be complete (ca 100%) to intermediate (40-50%) or low depending on extreme conditions, slope and solifluxion incidence. Succession towards tall vegetation types is prevented by extreme environmental conditions in the higher altitudes, where those grasslands are the Potential Natural Vegetation. Grazing, usually by sheep, is restricted to a short growing season and its impact used to be low.

The majority of the species are Iberian endemics, often restricted to one of the mountain groups and particularly abundant in Sierra Nevada.

Indicators of good quality:

• The grassland should be dominated by grasses (Festuca sp. pl.), grass-like species (Luzula sp. pl.) and other herbaceous plants, having few ligneous plants.
• A medium to high vegetation cover
• Absence of nitrophilic species linked to human activities
• No visible anthropic disturbances due to building activities, skying or intensive trampling

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats