The biodiversity of Sicilian traditional gardens

The potential value of private gardens for enhancing biodiversity has long been recognized; while, less investigated is the contribution of traditional gardens often collocated in the urban areas. Sicily, for its complex history and strategically central position in the Mediterranean basin, is an important crossroad of civilizations which influenced over the time the use of ornamental plants in traditional gardens. With the aim to investigate the biodiversity of Sicilian traditional gardens, the flora of 68 yards, dating from the late 19th to the middle of 20th century and located in the urban area of main cities (over 60, 000 inhabitants - 'Cities'), was analyzed, through a complete plant inventory, and compared with 97 gardens located in small cities (less than 60, 000 inhabitants) and in the rural area ('Rural'). The taxonomic richness, expressed by the use of Shannon (H'), Simpson (D) and Evenness (J) indices showed values of 5.8312 and 6.0270 for H', 0.7113 and 0.6915 for J and 0.0047 and 0.0040 for D, respectively for 'Cities' and 'Rural', and demonstrated the presence of a high plant biodiversity and even the presence of few dominant ones. In the 'Cities', 702 taxa of ornamental plants were identified, belonging to 369 genera and 116 botanical families. In the 'Rural' 935 taxa were identified, belonging to 457 genera and 134 botanical families. In the urban and rural areas 46.3 and 39.9%, respectively, of total taxa were present in only one garden. The richness of species found in Sicilian traditional gardens allows to consider them as "living plant collections".