The Olea europaea L. var. sylvestris (Mill.) Lehr. forests in the Mediterranean area

Abstract

This paper examines the forest communities dominated by Olea europaea L. var. sylvestris (Mill.) Lehr. that have been described up until now in the Mediterranean Region (including other isolated extrazonal areas in the northwestern Iberian Peninsula and in Northern Turkey) as more or less evolved aspects of woods, microwoods and high maquis that principally tend to make up climacic and edapho-climacic “series heads”. These forma- tions maintain a significant large-scale distributive potential within the infra- and thermomediterranean bioclimate belts (with a few penetrations into the mesomediterranean) with a dry-subhumid (and sometimes humid) ombrotype; however, they are currently quite rare and fragmented in the wake of large-scale deforestation and the impoverishment of old-growth communities dominated by a species known to live for millennia. The study was conducted through the analysis of phytosociological data taken from the scientific literature and other unpublished data regarding North-Africa (Morocco, Algeria), the Iberian Peninsula, the Balearic Islands as well as other islands from the Tyrrhenian area (Sardinia, Corsica, Sicily and its minor islands), the Italian Peninsula, the Balkan Peninsula, the Aegean region, Turkey and the southern Anatolian coast. A comparison between the different communities has shown a high floristic and physiognomic-structural homogeneity that justifies their categorization in the Quercetea ilicis class. The biogeographic and ecologic vicariance shown by the same formations within the large Mediterranean distribution range makes it pos- sible to subdivide them into the following orders and alliances: 1) Pistacio-Rhamnetalia alaterni [A) all. Tetraclini articulatae-Pistacion atlanticae (suball. Pistacienion atlanticae); B) all. Asparago albi-Rhamnion oleoidis; C) all. Oleo sylvestris-Ceratonion siliquae]; 2) Quercetalia calliprini [D) all. Ceratonio-Pistacion lentisci]; 3) Quercetalia ilicis [E) all. Querco rotundifoliae-Oleion sylvestris; F) all. Fraxino orni-Quercion ilicis; G) all. Erico arboreae-Quercion ilicis; H) all. Arbuto unedonis-Laurion nobilis (suball. Arbuto-Laurenion nobilis)]. Regarding the syntaxonomical aspect: (i) two new associations are described [Hippocrepido emeroidis-Oleetum sylvestris and Junipero foetidissimae-Oleetum sylvestris]; (ii) two new associations [Phillyreo latifoliae-Oleetum sylvestris Barbero, Quézel & Rivas-Martínez ex Gianguzzi & Bazan ass. nova and Calicotomo intermediae-Oleetum sylvestris Quézel, Barbero, Benabid, Loisel & Rivas-Martínez 1988 ex Gianguzzi & Bazan ass. nova] and a new subassocia- tion [Aro neglecti-Oleetum sylvestris Rivas-Martínez & Cantò 2002 corr. Rivas-Martínez & Cantò fraxinetosum angustifoliae Pérez Latorre, Galán de Mera, Deil & Cabezudo ex Gianguzzi & Bazan subass. nova] are leptotypified; (iii) a nomen novum of the association is redefined [Rhamno laderoi-Oleastretum sylvestris (Cantò, Ladero, Perez-Chiscano & Rivas-Martínez 2011) Gianguzzi & Bazan nom. nov.].