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Acta Botanica Gallica: Botany Letters 315

Risk factors intrinsic to the species are obviously tied Channel of Sicily. The graphical representation itself of
to the relictuality of the stations, placed here at the the range of S. mattiazzi (Figure 2) – with a predominant
extreme south-eastern limit of the range. These isolated Atlantic centre of gravitation – shows that the
populations are extremely sensitive to environmental Mediterranean stations are mainly located in the western
stresses and stochastic events likely to compromise their part of the respective territories (character of
survival (Lesica and McCune 2004) and to enhance and environmental oceanicity). In particular, the various more
increase the effects of human disturbance (Kappelle or less punctual sites distributed in the Tyrrhenian area
et al. 1999). Therefore, a strong risk of imminent loss of probably represent evidence of an ancient and
genetic diversity needs to be considered (Siikamäki and widespread occurrence of the species, confirming the
Lammi 1998). ancient palaeogeographic connections that affected the
In light of the population surveys carried out entire Mediterranean Region (Francini and Messeri,
(Table 5), and considering that the estimated extent of 1956; Caflisch and Schmidt Di Friedberg 1967; Catalano
2
occurrence is 5 km , the area of occupancy is 0.75 km – et al. 1995, 1996).
2
compared with an effective area of occupancy of On this basis, the status of the species in Sicily
2
0.00108 km ; hence, at regional level, the species is to is even more critical, given the limited extent of the
be ascribed to the category “Critically endangered”,in two populations and the small number of individuals,
accordance with the IUCN criteria B1ab (ii) and B2ab particularly in the Marettimo Island. Although both
(ii) (Gärdenfors et al. 2001; IUCN 2003, 2006). surveyed stations fall within Sites of Community
Importance (ITA010002 “Isola di Marettimo” and
ITA010010 “Monte S. Giuliano”) and that of the
Conclusion Marettimo Island lies within a Special Protection Area
Along the sectors of the Atlantic belt, S. mattiazzi is a (ITA010027 “Arcipelago delle Egadi – area marina
very common species. It becomes vulnerable in the more e terrestre”), some conservation programmes on
inland, disjointed stations distributed within the various levels would be appropriate to avoid a
Mediterranean area, where populations are often probable extinction of the species in the short term.
exiguous and fragmentary. For example, it is protected in In particular, we recommend (1) an ex situ cultivation
Catalonia, being included in the Catàleg de flora of the species, which may also allow some
amenaçada (Sàez, Aymerich, and Blanché 2010) and investigations on its reproductive strategies, either
considered “in danger of extinction”. vegetative or sexual; (2) a reintroduction of the
In Italy, it is included in the Regional Red Lists of species in stations adjacent to the surveyed areas; and
Conti, Manzi, and Pedrotti (1997), and its conservation (3) collection and storage, in a special bank, of seeds
status is considered as “threatened” in Lazio, collected in nature to ensure the existence of a
“vulnerable” in Campania; no reference is available in reserve of germplasm.
Sardinia, although it is also present in localized areas
and probably not free from hazards.
In Sicily, S. mattiazzi is undoubtedly an element of Acknowledgements
particular phytogeographical significance, with the two Prof. Gianguzzi is grateful to Prof. Salvatore Brullo (University
exiguous populations recently found on the Marettimo of Catania) for having stimulated this research, after his first
Island and on Mount S. Giuliano. They denote an discovery of the species on the Marettimo Island, on the
evident relictual character, becoming localized within occasion of the “Excursion of the Sicilian Section of the Italian
Botanical Society” (3-5 May 2003). This research was
an Erica multiflora garrigue, ascribed to the
supported by a contribution from ‘‘Ricerca d’Ateneo ex 60%’’,
Erico–Micromerietum fruticulosae, which also has its University of Palermo.
own relictual character, as its somewhat rich and peculiar
floristic composition demonstrates. The association,
circumscribed to some calcareous outcrops of western References
Sicily, is characterized by the presence of several Abate, B., C. Di Maggio, A. Incandela, and P. Renda. 1993.
endemics. Moreover, this paper also highlighted that the Carta Geologica dei Monti di Capo San Vito (scala 1/
aspects detected in the locality of Mount S. Giuliano are 25000). Palermo: Dipartimento di Geologia e Geodesia.
more intact and better preserved, unlike the population Abate, B., A. Incandela, F. Nigro, and P. Renda. 1998. Plio-
Pleistocene Strike-Slip tectonics in the Trapani Mts. (NW
of the Marettimo Island, which is made up by very few
Sicily). Bollettino della Società Geologica Italiana 117:
individuals and is probably more vulnerable. 555–67.
The calcareous dolomite rocky ridges, located near Abate, B., A. Incandela, and P. Renda. 1999. Geologia
the coast, represent the habitat in which these two dell’Isola di Marettimo (Arcipelago delle Egadi, Sicilia
populations live and where they are exposed to the occidentale). Naturalista Siciliano s. 4, no. 23: 3–41.
Abate, B., G. Lo Cicero, and P. Renda. 1982. Facies
marine humid currents from the west. This ecological
carbonatiche ed evaporitiche del Trias superiore di
combination gives to the two biotopes a peculiar Marettimo. Rendiconti della Società Geologica Italiana 5:
character that is not frequent in other sites of the 71–6.