Included here are the Azores, a group of nine volcanic islands situated in the North Atlantic. In geological terms these are the youngest of the Macaronesian Islands. The highest, Pico, reaches an altitude of about 2300m (the highest mountain in Portugues territory) and the three largest islands, São Miguel, Terceira and Pico represent about 69% of the total area of the archipelago.

Azorean Upland Calluna Heath

In the zones above 1500m Calluna vulgaris becomes the dominant heathland species although patches of endemic Doboecia azorica (Ericaceae) may also occur, while the summit rocks include acrtic-alpine bryophytes, particularly Gymnomitrium adustum and Racomitrium lanuginosum.

Azorean Upland Shrublands

Shrublands are scattered throughout the islands and may be dense or open or in some cases have emergent trees. The shrubs can be low growing like Calluna vulgaris, Thymus caespititius and the endemic Daboecia azorica (Ericaceae) or semi-arborescent such as Myrica faya, Laurus azorica and Juniperus brevifolia. Several types have been described. Erica mixed shrubland occurs on acid gravel slopes and is dominated by the endemic Erica azorica (Ericaceae) together with the endemic Juniperus brevifolia (Cupressaceae). These are open communities interspersed with scattered grasslands with species such as the endemic Holcus rigidus and Festuca petraeae (Poaceae), together with Huperzia selago, Lycopodium cernuum and the endemic Tolpis azorica (Asteraceae). Euphorbia shrublands dominated by the endemic Euphorbia stygiana (Euphorbiaceae) are usually small, scattered communities often associated with some form of disturbance. They are mostly seen on mountain slopes or deposits associated with slopes. Lajido shrublands are associated with so-called lajido formations – a term used on Pico Island to describe flat basaltic compact lavas where root penetration is almost impossible. The species that manage to colonise these areas are mainly found in fissures and typically include Calluna vulgaris, Laurus azorica, Myrsine africana, Thymus caespititius and the endemic Erica azorica and Daboecia azorica (Ericaceae). Volcanic sand shrubland is also distinctive but mainly confined to just three locations – Graciosa (Pico Timão), Cabeco do Fogo (Faial) and the ‘sand mountain’ (Pico). Typical species include Thymus caespititius, the endemic Corema album subsp. azoricum (Empetraceae) and Daboecia azorica (Ericaceae), together with herbaceous taxa like Centaurium scilloides, the endemic orchid Plantanthera micrantha (Orchidaceae), and the moss Racomitrium lanuginosu.

References

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