Macaronesian rocky sea cliff and shore

This habitat comprises the rocky sea cliffs of the Macaronesian islands, which are formed by a narrow strip of lava bedrock (basalt) that is influenced by salt spray from the sea. Some of the Macaronesian coastal cliffs are among the highest sea cliffs in Europe and the world, like the Cliffs of the Giants along the western coast of Tenerife, with vertical walls reaching 500 meters above sea level, and the cliffs of Gabo Girao in Madeira, reaching a height of 540 m above sea level. The habitat refers to the area that is still under influence of the sea (waves, salt spray and strong wind), but above the mean high tide (supralittoral). The sea cliffs of the Macaronesian islands differ from those of the temperate Atlantic coast and the Mediterranean coast due to the dominance of a set of Macaronesian endemic species. The cliffs of the different island groups also show a diversity in species composition, which is expressed in three alliances of the class Crithmo-Limonietea: Frankenio-Astydamion of the Canary island, Helichrysion obconico-devium of the Madeiran archipelago and Euphorbio azoricae-Festucion petraeae on the Azores. In the Canary islands, the most characteristic species of sea cliffs are Astydamia latifolia and several endemic species of Limonium. Species that are also found at Atlantic and/or Mediterranean sea cliffs are Crithmum maritimum, Plantago coronopus, Frankenia laevis, Frankenia pulverulenta, and Asplenium marinum. Additional characteristic species which are restricted to the Canary islands are Plantago aschersonii, Lotus glaucus, Argyranthemum frutescens, Frankenia ericifolia, Atractylis preauxiana, Reichardia crystallina and Reichardia ligulata. The characteristic Limonium species are often restricted to only one or two islands, like Limonium imbricatum (La Palma, Tenerife), Limonium fruticans (Tenerife), Limonium macrophyllum (Tenerife, Gran Canaria) and Limonium brassicifolium (El Hierro, La Gomera). Limonium pectinatum (including L. humboldtii) is a more widespread species of coastal cliffs, found on most of the Canary Islands and also on Selvagens. Limonium papillatum is found on coastal cliffs of Lanzarote and Fuertaventura, but also on the smaller islands Alegranza, La Graciosa, Lobos and Selvagens. On Madeira the endemic shrubs Helichrysum  obconium and Helichrysum devium form different plant communities of coastal cliffs. Other characteristic species are Lotus glaucus, the endemic Limonium pyramidatum, Crithmum maritimum, Lotus loweanus, Frankenia laevis and Plantago coronopus. In the Azores, the most characteristic species are the endemics Azorina vidali, Daucus carota subsp. azorica, Euphorbia azorica, Festuca petraea, Myosotis maritima, Solidago sempervirens subsp. azorica and Spergularia azorica. Juncus acutus grows on littoral lava bed depressions that are temporarily submerged in sea water, but also on rocky shores. Like in other coastal regions in the Macaronesian archipelagos, an altitudinal gradient with different zones may be distinguished within the cliff habitat, from the supralittoral belt to the cliff top, with algae and lichens on the lowest parts and transitions towards succulent vegetation and thicket on the higher cliffs. Additionally, in the Macaronesian archipelagos coastal cliffs and small islands form important nesting sites to pelagic and coastal seabirds, especially where these are inaccessible to predators and undisturbed by human or animals (e.g. no grazing). Important birds of the Macaronesian coastal cliffs are several species of Petrels and Shearwaters.

Indicators of good quality:

• No human or animal disturbance (e.g. no grazing)

• Presence of sea bird colonies

• Presence of characteristic zonation belts

• Absence of alien plant species (like Mesembryanthemum sp., Carpobrotus sp.)

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats