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314 L. Gianguzzi et al.

Table 5. Ecological and stational characteristics of the two particularly true in the central-southern part of the Italo-
surveyed sites. Thyrrhenian Province, where, in addition to a high
Tableau 5. Caractéristiques écologiques et stationnelles des concentration of endemism, species with a wider
deux localités étudiées.
distribution have found refuge stations. The two
Ecological and Punta Bassana Mount S. Giuliano exiguous stations of the S. mattiazzi, entity, bearing a
stational data (Marettimo Island) (western Sicily) Mediterranean–Atlantic centre of gravitation, located at
the extreme south-eastern limit of the range, fall within
Administrative Favignana (Trapani) Erice (Trapani)
province the latter category.
UTM coordinates TC 43.04 TC 88.16 Monitoring of the individuals of the two stations –
Altitude (m above 120 270 whose ecological and stational data are summarized in
sea level) Table 5 – was made to assess their vulnerability state
Slope (°) 45 10 according to IUCN criteria (IUCN, 2001, 2003, 2006).
Aspect NE NW
Substrate limestone limestone Given the lack of previous data, a field survey was
Bioclimate lower thermo- upper thermo- performed over the period 2005–11 (Marettimo Island:
Mediterranean lower Mediterranean lower Punta Bassana) and 2011/12 (Erice: Mount S. Giuliano).
subhumid subhumid At first glance, in both stations, although punctual,
2
Occupied area (m ) 80 1000 the taxon would seem not to be subjected to immediate
Mature individuals 8 c.350
Endemic species co- 1 7 risks caused by direct threats, because of the peculiarity
occurring of the habitat and factors intrinsic to the species. The
Other rare species 2 2 calcareous rocky ridges in which it settles represent a
co-occurring very specific environment, free of urban and agricultural
pressures and other threats such as the naturalization of
The garrigue – diversified by the endemic species invasive species. Hence, no reduction of the surface and
Micromeria graeca subsp. fruticulosa, which is very no alteration of its level of naturalness is to be
frequent in both stations (Table 1) – is ascribed to the anticipated in the short term. Moreover, the species is
Erico–Micromerietum fruticulosae (Cisto–Ericion, not a fodder or pasture entity, so it is not subject to
Cisto–Micromerietea) association. This coenose is major damage by grazing weighing on the territory, and
spread along the calcareous dolomite relieves of the the tuberous roots of the species confer on it a certain
Aegadian Islands and north-western Sicily (Brullo and fire resilience (Trabaud 1987; Saracino and Leone 2004;
Marcenò 1983), already reported for the areas of Mount Canadell and Lopez-Soria 1998).
S. Giuliano and Mount Cofano (Gianguzzi and La However, clearly, the small size of the two
Mantia 2008). populations constitutes in itself a major risk factor,
The presence of S. mattiazzi in the Brachypodium because they are isolated and at a considerable distance
retusum grasslands was detected in the station of Mount from the closest stations, as well as being far from the
S. Giuliano (Table 2) where the coenose occupies main range. Also, although the species is somewhat
restricted linear surfaces, placed between the Erica shrub resilient to fire, in the Mount S. Giuliano station the fires
and the most eroded part of the rocky plateau, close recur almost every year (Gianguzzi and Ottonello 2000;
to the cliff. The grassland itself is referred to Gianguzzi and La Mantia 2008), which may induce a
the Helminthotheco aculeatae–Brachypodietum retusi disturbance of the populations. The passage of fire during
association, described also for the calcareous relieves of the spring–summer interferes negatively both with the
north-western Sicily (Brullo et al. 2006, 2010). The reproductive capacity of the species and with its growth
presence of the species in aspects with Brachypodium biology, not to mention the ecological–environmental
was already reported in Corsica (Paradis 2010). upheavals caused to the respective phytocoenoses and to
In a syndynamic perspective, the two surveyed the habitat. Moreover, the soil, in addition to being
associations for the territory of Mount S. Giuliano fall in exposed to the erosive effects resulting from weathering,
the Holm Oak vegetation series tied to the compact is subjected to the laterization (De Lillis 1995), altering
limestone (Pistacio lentisci–Querco ilicis sigmetum), the water retention capacity of the soil pockets in which
already described for the area of Mount Cofano the species is settled (De Bano 1981, 2000).
(Gianguzzi and La Mantia 2008). In the Marettimo Additional impacts are related to the reforestation
Island, the above garrigue of the Erico–Micromerietum interventions on denuded slopes – very frequent in the
fruticulosae is instead tied to the xerophilous series of territory – which cause an increase of the erosive
the Periploco angustifoliae–Euphorbio dendroidis phenomena from digging holes, steps, etc. (Gianguzzi
sigmetum (Gianguzzi, Scuderi, and La Mantia 2003a). 2007). These interventions induce other environmental
modifications through the shading of the topsoil and the
Population analysis and assessment of the risk level increase of allelopathic substances in the soil brought by
Sicily and circum-Sicilian islands are among the main the non-native species (genera Pinus, Cupressus,
centres of plant diversity in the Mediterranean basin Eucalyptus) usually used (Saracino, Fascetti, and Leone
(Médail and Quézel 1999; Brullo et al. 2002). This is 2002).