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Fig. 3: examples of Sicilian UNESCO world heritage: the Greek theatre of Taormina, built in the third
century BC with Mt. Etna in the background (above, left); the rocky Necropolis of Pantalica, con-
taining over five thousand tombs carved from the 13th to the 7th century BC and vestiges of
Byzantine early medieval settlements (above, right); the temple of Segesta, built in the 420’s BC
and left unfinished because of the Carthaginian conquest of the city (bottom, left); Cloister and
Arab cistern of San Giovanni degli Eremiti, founded as a church in the 6th century AC, converted
into a mosque after the Islamic conquest of Sicily and returned to the Christians by Roger II, after
the establishment of the Norman domination in Palermo (bottom, right). (Photos Guarino)
The remarkable landscape diversity of Sicily had a direct influence not only on the number
of species, speciation processes and genetic variability in the natural vegetation, but also on
the human cultural diversification and stratification, which is one of the main features of the
island. In the last ten thousand years, since the beginning of agriculture and commercial trad-
ing, the human activity increased the natural patchiness of the Sicilian landscapes up to the
exasperation. Many alien plants reached the island from their original milieus and, in some
cases, they gave rise to new polyploid populations, sometimes hybridogene, which occasion-
ally (see, for instance, Poa annua and Veronica persica) achieved a worldwide success
(BRULLO & GUARINO 2007).
Even if the effects of the human interaction with the native flora, in terms of species migra-
tion and habitat fragmentation, are rather evident and relatively well known, also in this case
there are some still unsolved open questions: for instance, it is hard to explain why some spe-
cies, which in the Eastern Mediterranean are clearly favoured and spread by transhumance
and pastoralism, in Sicily remained shelved on the Hyblaean Plateau, without having spread
to the carbonatic substrates of the rest of the island. This is the case of Phlomis fruticosa,
Ferulago nodosa, Salvia triloba, Sarcopoterium spinosum which are very common in the
Hyblaean district but absent from the rest of the island, if we except some small and localised
occurrences of Phlomis fruticosa near Palermo (GIANGUZZI et al. 1995) and in the Peloritani
Mts. (SCIANDRELLO et al. 2013).

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