Annual dune plant communities in Sicily: new insights through the statistical approach

The ephemeral dune plant communities of the Mediterranean Region are grouped in Helianthemetea guttati class. Here we find the Cutandietalia maritimae order, proposed by Rivas-Martinez et al. (2002), with annual associations of semi-fixed dunes, and the Malcolmietalia order, proposed by Rivas Goday (1958), comprising the inland sandy soil communities, which occurs in the clearings of bushes and woodlands in the themomediterranean dry belt. The aim of this survey is the analysis and review of all syntaxa described in Sicily, related to annual dune vegetation, in order to provide a coherent phytosociological synthesis taking into account the floristic, chorologic, and ecological features. The vegetation relevés have been made according to the sigmatist phytosociological approach (Braun-Blanquet 1964). On the whole more than 280 relevés were submitted to UPGMA with Bray–Curtis coefficient using SYNTAX 2000 software (Podani 2001). The ordination of the data-sets was performed using the PC-ORD 4.34 software. Detrended Correspondence Analysis (DCA) (Hill and Gauch 1980) was used to establish spatial patterns in the scattergram and to generate hypotheses on the vegetation/environment relationships. For processing the data, relevés of literature (Brullo & Marcenò, 1974; Brullo et al. 1974; Brullo & Grillo, 1985; Brullo et al. 1988; Bartolo et al. 1990; Brullo et al. 1994; Brullo & Scelsi, 1998; Brullo et al. 2000; Minissale & Sciandrello 2005;2010) as well as several unpublished relevés were taken into account to run the ordination and cluster analysis. Based on the processed data, it is proposed the following syntaxonomic scheme that highlights the floristic and ecological significance, at the level of orders and alliances, including the ephemeral psammophilous vegetation of Sicily. Nomenclatural and taxonomical aspects are referred to Giardina et al. (2007). Malcolmietalia Rivas Goday 1958 Spring flowering pioneer therophitic communities growing on deep sandy soils in the thermomediterranean belts of the Mediterranean Region (Dìez-Garretas et al. 2003). Characteristic species: Avellinia michelii, Brassica tournefortii, Coronilla repanda, Corynephorus articulatus, Evax asterisciflora, Lotus halophilus, Medicago littoralis, Ononis diffusa, Rumex bucephalophorus. Evaco asterisciflorae-Linarion humile all. nova prop. Ephemeral therophitic community from fossil dunes and deep sandy soils of the Camarino-Pachinense disctict (Brullo et al. 2011) Characteristic species: Astragalus kamarinensis Linaria multicaulis subsp. humilis, Loeflingia hispanica, Senecio glaucus subsp. hyblaeus, Tuberaria villosissima var. sicula. Cutandietalia maritimae Rivas-Martìnez, Dìez-Garretas & Asensi 2002 Ephemeral plant communities growing on coastal sands and dunes with salt spray between the perennial vegetation of Ammophiletea class. Characteristic species: Anthemis peregrina, Catapodium hemipoa, Cutandia maritima, C. divaricata, Erodium laciniatum, Ononis serrata, O. variegata, Phleum arenarium, Polycarpon diphyllum, Pseudorlaya pumila, Rostraria littorea subsp. littorea, Silene niceensis, Triplachne nitens, Vulpia fasciculata. Alkanno-Maresion nanae Rivas Goday ex Rivas Goday & Rivas-Martínez 1963 corr. Díez Garretas, Asensi & Rivas-Martínez 2001 Ephemeral therophitic communities of the coastal dunes spreading in the Mediterranea Region, from East-Iberian territory to Macedonian and Cretan coast, also reaching coastal areas between Algiers and Gulf of Hammamet (Tunisia) (Dìez-Garretas et al. 2003). Characteristic species: Alkanna tinctoria, Echium sabulicolum, Hormuzakia aggregata, Maresia nana, Matthiola tricuspidata, Senecio glaucus subsp. coronopifolius, Silene nummica, Wahlenbergia nutabunda. Laguro ovati-Vulpion fasciculatae Géhu & Biondi 1994 Ephemeral psammo-nitrophilous communities of the coastal dunes spreading in the Mediterranean Region. Characteristic species: Chamaemelum mixtum, Lagurus ovatus, Anisantha rigida.