Rediscovery of a relict Searsia tripartita maquis in Southwestern Sicily (Italy) with data on habitat 5220

This paper reports the presence of a nucleus of thermophilous maquis with Searsia tripartita within the “Monte San Calogero” Nature Reserve (Sciacca, Southwestern Sicily, Italy), within a Natura 2000 site (ITA040009). S. tripartita is a summer-deciduous shrub with a South-Mediterranean distribution range, which is relatively common in North Africa but with only a few disjunct occurrences in Sicily. Here we report on a site that is located at the northern limit of the species’ range. The local occurrence of the species was reported for the first time some 200 years ago by Gussone, as testified by two herbarium specimens kept in the Gussone Herbarium of Naples. This study explores the synecology and the dynamic trends of the S. tripartita maquis using vegetation field surveys and a diachronic analysis of historical images spanning 27 years, from 1998 to 2024. The plant community colonizes an extremely dry and stony area at the base of carbonate rocks, subject to dry-semiarid thermomediterranean bioclimatic conditions. The surveyed plant community can be referred to Calicotomo infestae-Rhoetum tripartitae , a distinct low maquis association considered endemic to southern Sicily, framed within the southern Mediterranean alliance Periplocion angustifoliae (order Pistacio-Rhamnetalia alaterni , class Quercetea ilicis ). Additional considerations are given to the conservation status of the rare habitat of Community interest 5220* (Habitats Directive 92/43/EEC) in which this community is classified.