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| Macaronesia is a biogeographical region comprising five Atlantic Oceanic
archipelagos: the Azores, Madeira, Selvagen (Savage Islands), Canaries and Cape
Verde. It has strong affinities with the Atlantic coast of the Iberian Peninsula and
the north-western fringes of Africa. This paper re-evaluates the biogeographical
history and relationships of Macaronesia in the light of geological evidence, which
suggests that large and high islands may have been continuously available in the
region for very much longer than is indicated by the maximum surface area of the
oldest current island (27 Ma) – possibly for as long as 60 million years. We review
this literature, attempting a sequential reconstruction of Palaeo-Macaronesia
from 60 Ma to the present. We consider the implications of these geological
dynamics for our understanding of the history of colonization of the present
islands of Macaronesia. We also evaluate the role of these archipelagos as stepping
stones and as both repositories of palaeo-endemic forms and crucibles of neoendemic
radiations of plant and animal groups. Our principal focus is on the
laurel forest communities, long considered impoverished relicts of the Palaeotropical
Tethyan flora. This account is therefore contextualized by reference to the
long-term climatic and biogeographical history of Southern Europe and North
Africa and by consideration of the implications of changes in land–sea configuration,
climate and ocean circulation for Macaronesian biogeography. We go on
to provide a synthesis of the more recent history of Macaronesian forests, which
has involved a process of impoverishment of the native elements of the biota that
has accelerated since human conquest of the islands. We comment briefly on
these processes and on the contemporary status and varied conservation
opportunities and threats facing these forests across the Macaronesian biogeographical
region. | |
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