Two populations of Simethis mattiazzi (Xanthorrhoeaceae) were recently discovered in the Channel of Sicily – (1) Punta Bassana (Marettimo Island) and (2) Mount S. Giuliano (western Sicily) – at a considerable distancefrom the nearest stations hitherto known, located in southern Sardinia, the Pontine Islands Archipelago and Tunisia. Thetaxonomical and distributive aspects of this species are analysed to highlight the relictual and biogeographicalsignificance of the disjointed and fragmentary nuclei distributed in several small islands of the Channel of Sicily, theItalian Peninsula and North Africa. Some morphological, biological, ecological and phytosociological aspects of the twonew populations are analysed to assess risk factors. These relictual populations are included in a residual garrigueascribed to the association Erico–Micromerietum fruticulosae, endemic to western Sicily and characterized by asignificant frequency of endemic or rare species. The coenose is tied to the calcareous dolomite rocky ridges locatednear the coast and exposed to humid currents from the sea; this ecological combination gives to the habitat a characterof oceanic environmental conditions, somewhat similar to the Atlantic stations where the main range of the speciesgravitates. The survey has shown the populations to be formed of a small number of individuals at both stations, whichhas further highlighted the biological precariousness of these populations, located at the extreme south-eastern limit ofthe range of the species. The threats of anthropogenic nature, such as reforestation with non-native conifers, but mostlyby fires, the frequency of which tends to alter the integrity of the sites, increase this vulnerability. The IUCN “riskstatus” for the regional territory of Sicily of S. mattiazzi is to be ascribed to the “Critically endangered” category, inaccordance with the B1ab (ii) and B2ab (ii) criteria of the IUCN. The same “risk status” is likely to be extended to the other isolated stations of the western Mediterranean.
|Numero di pagine||16|
|Rivista||ACTA BOTANICA GALLICA|
|Stato di pubblicazione||Published - 2012|
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