Macaronesia
The nine major islands of the Azores (from largest to smallest: Sao Miguel, Pico, Terceira, São Jorge, Faial, Flores, Santa Maria, Graciosa, Corvo) are located at the most northwestern point of Macaronesia and quite isolated about 1500 km west of Portugal. The seven main islands of the Canaries (from west to east: El Hierro - smallest island, La Palma, La Gomera, Teneriffa - largest island, Gran Canaria, Fuerteventura and Lanzarote) are located much more near the southern coast of Morocco. Fuerteventura is only separated by 100 km of Atlantic ocean. The Madeira archipelago, which is located between the other two archipelagos (but nearer to the Canaries than to the Azores), is dominated by the eponymous main island Madeira and otherwise consists of only one other small island (Porto Santo) and a few uninhabitated rock islands (Ilhas Selvagens and Ilhas Desertas).
Each of these islands is of vulcanic origin and thus never had connections to any mainland. Vulcanism has partly already ended some centuries ago or even longer (e.g. La Gomera), but is still going on, for example, in some of the Azores, La Palma, near El Hierro or Lanzarote. Most islands are very mountainous. Only in the islands of the oldest origin (e.g. Fuerteventura) erosion has already moderated this (Fuerteventura: highest peak around 800m above sea level, Lanzarote 600m, Tenerife on the other hand 3718m at the Teide summit, other islands mostly between 1000 and 2000m above sea level). The isolation results in relative small species numbers but also in a relative high percentage of endemic species. The Azores show the lowest species numbers due to their extreme isolation.
Climatic conditions
The climate is relative mild all the year, subtropical near the coasts, and shows only small seasonal fluctuations (islands of the ever lasting spring, day temperatures between about 19 and 26 degrees Centigrade on the coasts of the Canaries, Azores a bit cooler). Only if the wind comes from southeastern direction direct from the Sahara desert, there will be short heat periods mainly in the Canaries and Madeira. Most important for the climatic conditions are the balancing effects of the Gulf Stream (respectively its offshóot Canary Stream), which cools in summer and prevends temperatures to fall too much in winter, and the often steadily blowing North-easterly Trade Winds. This Trades result in an impounding of the humid air especially on the northeastern sides of the islands or their mountains. During ascension the humidity is condensating to mist in heights most often between around 500 and 1500 m above sea level. Rain is falling most often in Winter (in the Azores all year). In winter there may be snow fall in the higher mountains above 1800m, but in the Canaries, for example, snow melts quickly except for the Teide. In the Canaries there is a distinct decrease in humidity from west (La Palma, the greenest Canarian island) to east (Fuerteventura, semi-desert conditions at least nowadays).
Vegetation
Because of the different height zones and the winds you can distinguish most often the following vegetation units.
Coastal areas
In most of the islands there are rocky coasts with only narrow belts of halophytic plants (e.g. Astydamia latifolia). In a few islands (especially Fuerteventura, also in the very south of Gran Canaria) there are locally large sand dunes with halophytic plants near the sea (e.g. Zygophyllum fontanesii), semi-shrubs as Launaea arborescens, which also grows on stony slopes,
and especially a rich flora of annual plants (after winterly rainfalls) with Calendula, Rumex, Echium etc.
Dry and hot succulent belt
This zone can be observed especially near the coasts and ascend upt to around 500m above sea level (on the drier southern sides of the islands up to more than 1000m above sea level). This succulent belt shows a relative gappy growth with dry-resistent, often water storing species like Euphorbia sp., Kleinia neriifolia, Rumex lunaria, Periploca laevigata, Lavandula canariensis etc. In the gaps between the perennial species you can observe many annual species especially after rain falls (e.g. Calendula, Rumex vesicarius, Silene, various Brassicaceae, grasses, Bidens, Echium, Malva). This succulent belt largely lacks in the humid Azores.
Pine woodlands
In some islands (especially the Canary Islands La Palma, Tenerife and Gran Canaria) there are large woodlands with mostly the only tree species Pinus canariensis (endemic).
In the mostly only sparse undergrowth you will find species like Cistus or brooms. The pine trees comb the fog humidity with their needles and so multiply precipitation. But these woodlands gernerally occur in drier zones than the laurel-leaf woodland and can be also found in the dry high mountains above the main fog zone until over 2200m above sea level.
In these forests there are only a few butterflies and moths, especially the Lymantriidae Calliteara fortunata and the Noctuidae Bryonycta pineti. Due to their thick bark, Canarian pine forests are well-adapted to sporatic (but not to frequent) fires (driving out from stems and thick branches).
Laurel-leaf zone (Laurisilva, Monte verde)
A particularity of Macaronesia are the laurel-leaf woodlands, which are relicts of the Tertiary. At these ancient times such evergreen, humid, and constant cool-subtropical woodlands also occurred in North Africa and South Europe, where they became extinct due to climatic changes. As last very poor remnants you may consider the Erica arborea-bushland in the southwestern Iberian Peninsula. In Macaronesia these woodlands have survived only because of the humid Trade Winds and thus are located mainly on the north-easterly sides of the islands or their mountains between about 500 and 1600m above sea level (especially in Barrancos and in the more northerly islands even lower). Formerly (about the year 1500) such woodland also existed in the mountains of Fuerteventura where they have been completely destroyed by man. Well developed examples are rare nowadays. You can find this type of woodland in somewhat larger extent only on Madeira, La Gomera (Garajonay National Park), La Palma (in the northeast and less well developed on some eastern slopes of the Cumbres) and Tenerife (Anaga, Teno). Smaller remnants also occur in the north of Gran Canaria or on El Hierro) and in the Azores (here many areas clearcutted for cow pastures).
Laurel-leaf woodlands mostly consist of evergreen trees and bushes like Laurus azorica, Apollonias barbujana, Viburnum tinus, Myrica faya and Erica arborea. The last two species often just remain after degradation by man or naturally at the drier borders of the woodlands as out posts (Brezal-Fayal). In dense laurel-leaf forest there are comparatively few species in the dark undergrowth, such as Tradescantia, Urtica morifolia, various ferns, Geranium or Pericallis, which serve as food for Noctuidae (Euplexia, Mniotype schumacheri) or the Arctiidae Canararctia rufescens. Only at brighter places there is a denser herb growth.
High mountain zones
In altitudes above the mist zone (above about 1600m ) the climate is noticeable drier again. The areas above 2000-2300 m above sea level are often covered with very dry, gappy
and lower shrub communities (e.g. dominated by Spartocytisus supranubianus) and summer-flowering perennials (Erysimum scoparium, Descurainia bourgeaunana, Scrophularia sp.,
Argyanthemum sp., Echium sp. etc.). These altitudes are only reached in La Palma and especially Tenerife (Mount Pico in the Azores shows a different vegetation).
In an entomofaunistic point of view these areas are not too interesting. True high mountain species are rare (among the locusts a Sphingonotus-species and among the
Noctuidae Euxoa beatissima, both Tenerife).
Characteristics of the Azores
The more humid Azores have originally been also densely covered by laurel woodland. Only in the Uplands there occurred already prior to human arrival more open mossy dwarf shrub heathland and small bogs.
Until today most laurel woodland has been transferred into cattle pastures and also into coniferous forests in the higher altitudes.
But despite this many natural and semi-natural habitats are still existing mostly in barrancos (mostly wooded) and in the Uplands. In the higher altitudes this involves mostly steep
Festuca-, moss- and lichen-rich slopes with dwarf shrubs (Erica and others). In some places you can observe very recently a first shift back to laurel forests. But some of the endemic species (e.g. Phlogophora) also cope with the fern understory of coniferous monocultures.
A further characteristic are the many crater lakes and a further problem the many invasive plants.
Lepidoptera and locusts
Altogether, species numbers are relative low in both groups because of the isolating island effect, even if there is a high percentage of endemic species especially among the locusts (genus Calliphona, Arminda, Acrostira, Shingonotus etc.) and moths (e.g. Noctuidae: Noctua noacki, Leucania fortunata, Euplexia euplexina etc.). Among the butterflies there also are some endemisms (especially in the Canaries), for example Pieris cheiranthi, Pararge xiphioides and P. xiphia (the former in the Canaries, the latter on Madeira), Hipparchia wyssi respectively its species group, Hipparchia madeirensis, Gonepteryx cleobule (repectively its species group) and the Blue Cyclyrius webbianus. With Hipparchia azorinus (respectively the related taxa of the species group), only one endemic butterfly group is known from the Azores (but some moths as well, e.g. Phlogophora sp.).
The Lepidoptera of Macaronesia mainly consist of the following groups:
- Palaeotropical to subtropical species, that are widespread in Africa and reached the region due to their flight activity (and/or wind support) and especially settled the lower and medium altitudes. Among these there are some Plusiinae such as Cornutiplusia circumflexa or Chrysodeixis chalcites, further Noctuidae like Spodoptera littoralis or Hypena lividalis as well as the butterfly Catopsilia florella, the Sphingids Hippotion celerio or Acherontia atropos and many others.
- (South)European to Holomediterranean species (Argynnis pandora, Lycaena phlaeas, Polyommatus cramera, Noctua pronuba, Xylena exsoleta etc.)
- Endemic species, whose ancestors partially origin from Europe or North Africa as it is the case with Eilema albicosta, Pieris cheiranthi or Gonepteryx cleobule. Quite a high percentage of these endemisms (especially among the Noctuidae) settles in the native laurel-leaf woodland (Xestia mejiasi, Euplexia, Phlogophora, Mniotype schumacheri).
- Nearctic species, which occur in both the Americas and the Atlantic Islands. Here you can naturally find only very few species such as Vanessa virginiensis, Galgula partita or Danaus plexippus.
- Eremic species, which occur in the Sahara desert and invaded most often the drier eastern Canaries (especially Fuerteventura) such as Polytela cliens, Pandesma robusta or Hyles tithymali. This group lacks in the Azores.
Endangerment
The Macaronesian habitats are threatened by the extension of human settlements (e.g. on islands with high population density as Tenerife, Gran Canaria or southeastern Madeira), agriculture (bananas, pastures etc.), fires (often caused by man) and very heavily by the ever extending mass tourism. Thereby the endangerment is most severe in the lower altitudes (especially at the coasts) and lowest in pine woodland or higher mountains. Even today, the protected laurel-leaf woodlands still decrease, often due to fires as on La Gomera in late summer 2012 where a huge man-made fire also affected the Garajonay national park. This fire was supported by an extreme dry winter 2011/2012 and a dry summer. Different from the pine woodland the laurel-leaf woods are not adapted to fire at all. But the normally relative fire-resistent pine forests can be damaged by too frequent fires, too. There obviosly also is some climatic change which manifests itself in a decreasing steadiness of the Trade Winds. But this has to be surveyed for longer periods.Even the nowadays semi desert island Fuerteventura got its appearance not before the Europeans clearcutted all woodland and kept more and more goats.
The main endangerment factor these days is the mass tourism which destroys ever more areas. You just should risk a glance at the dunes of Maspalomas which are under protection. The whole sensible area is virtually enclosed by huge hotel complexes and the thus attracted human masses are not subserving the rest of dune vegetation. As a minimum postulation there should be no more increasement in bed capacities and thus no more new hotels.
Some photos...
