Page 10 - PastaLaMantia_2013

The vascular flora of the satellite islands of Sicily

vascular plants; No. hab = number of terrestrial habitats; No. end isl = number of endemics
exclusive to the given island; No. end arch = number of endemics on the archipelago; No.
end sic = number of endemics of the whole Sicilian region; No. excl arch = number of taxa
exclusive to the given island; surf refers to the surface area measured in hectares.; rou =
main rock outcrop (c = prev. calcareous, v = prev. volcanic); cli = bioclimate following
Rivas-Martínez (2008): i = infra-, t = thermo- and m = meso-mediterranean; dis =
distance from the nearest mainland (measured in Km). N.B.: the sharpest differences
between present and past distances are underlined; the nearest mainland is Calabria
for Stromboli, Panarea for Lbi, Str for Stc, and Africa for Lampedusa, Linosa, and
Pantelleria. During the LGM, the nearest mainland for Linosa and Pantelleria was Sicily.

Geological (and geological disturbance) history
If we go back millions rather than thousands of years in geological history,
the picture becomes even more complex. Although many palaeontologists (e.g.,
Rook et al., 2006) share the opinion that most of Sicily rose out of the sea only
during the Miocene (i.e., 23­–5.3 Mya), many others argue that repeated emersion
events may have occurred earlier, i.e., during the Mid Cretaceous (120–90 Mya:
Zarcone et al., 2010) or at least since the Oligocene (34–23 Mya: Rosenbaum
et al., 2002). These fragments of land may have acted as ‘stepping stones’ for
plant migration between Eurasia and Africa even before the Mediterranean
Sea acquired its present size and shape. Within this context, only the island
of Marettimo may have experienced partial emersion as long as 230–200
Mya (Martini et al., 2007), while all the other islands have a more recent and
discontinuous history of connection with the main island. For example, only a
few volcanic islands emerged ca. 1.5 Mya, while most of them (e.g., the Aeolian
Archipelago) appeared more recently (Calanchi et al., 2007). The ancient and
long-lasting isolation of Marettimo probably accounts for much of its floristic
originality. In fact, the western-most island of the Egadi Archipelago hosts the
only known Sicilian population of four species of high phytogeographic interest,
while the only extant relatives of several local endemics currently occur very
far away. For example, Thymus nitidus is related to T. richardii subsp. ebusitanus
of Ibiza as well with T. richardii subsp. richardii of Majorca and the former
Yugoslavia (Morales, 1997); Bupleurum dianthifolium is related to B. barceloi
of Majorca; and Pseudoscabiosa limonifolia is closely related to P. saxatilis of
southern Spain.
As a consequence of the tectonic uplift of southern Spain and NW Africa, at
the end of the Miocene (5.96–5.33 Mya), the Mediterranean Sea was separated
from the Atlantic Ocean, and its waters gradually dried and disappeared.

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