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Azores

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Terrestrial Biodiversity


The fact that the Azores is composed of islands (i.e isolated regions) contributes to the emergence of endemic species that constitute a unique natural heritage of global importance. Of the 4467 species and subspecies of terrestrial plants and animals known to inhabit this archipelago, 420 are endemic, some of which are confined to few or only one location!

Fig 6 Notwithstanding this significant percentage of terrestrial endemism, the native fauna and flora of the Azores is impoverished when compared to the other Macaronesian archipelagos (Madeira and the Canary Islands). Given the isolation of the Azores, the ancestors of all the terrestrial endemic species found in the archipelago had to travel over a significant water distance (more than 1200 km) from neighbouring Europe and about 800 km from Madeira Island. Additionally, the Azores archipelago is geologically young and colonization by flora and fauna occurred over a short geological period. Accordingly, it is of no surprise that the only indigenous terrestrial vertebrates are bats (two species) and birds (16 species) (Borges et al., in press). Among these is the Azores bullfinch (Pyrrhula murina), an endangered bird species with a population of about 250, included in the IUCN Red List, whose population is restricted to the cloud forest on the east of the Island of São Miguel (McGinley, 2007).

Table I: Number of currently known terrestrial species and subspecies in the fauna and flora of the Azores (based on the catalogue of Borges et al., 2005 in Borges et al., in press).
Total   
Endemic
Algicolous fungi 1 0
Lichenicolous fungi 22 0
Lichens   
551   
12
Bryophyta   
438   
9
Plantae   
947   
68
Nematoda   
80   
2
Annelida   
21   
0
Mollusca   
111   
49
Arthropoda   
2227   
267
Chordata   
69   
13
TOTAL   
4467   
420

Regarding native plant communities, laurisilva - a humid evergreen broadleaf laurel forest – was considered up until recently to be one of the predominant vegetation forms in the Azores. The Azorean laurisilva differs from that found on Madeira and on the Canary Islands, in terms of species composition. Today, only 2% of the original Laurel forest cover has been spared from deforestation.

Fig 7
Fig 8
In contrast to other Macaronesian archipelagos, the Azores only has one endemic genus of vascular plants (Azorina). After human settlement, other types of vegetation cover became progressively dominant. Presently, they include pastureland, production forest (mostly with Cryptomeria japonica), mixed woodland (dominated by non-indigenous taxa), field crops and orchards, vineyards, hedgerows, and gardens.

Fig 9_These islands were discovered in the fifteenth century, and more than 500 years of human settlement have taken their toll on the local fauna and flora. The indigenous flora and fauna have been under severe pressure from deforestation, agriculture and the introduction of invasive species. Approximately 70% of the vascular plants and 58% of the arthropods found in the Azores are exotic, many of them invasive.