The sabulicolous therophytic associations in Sicily: new insights through the statistical approach stressing on the continuum vs discrete model of plant communities

This study presents an updated syntaxonomic review of the annual psammophilous plant communities fromcoastal dunes and inland territories of Sicily. A total of 301 relevés were collected. The relevés data were analysed usingclassification (WPGMA, similarity ratio) and ordination methods (detrended correspondence analysis and principalcomponent analysis). Eighteen plant communities were recognized, four of which are described here for the first time(Rostrario littoreae-Tuberarietum villosissimae, Filigini asterisciflorae-Loeflingietum hispanicae, Astragalo kamarinensis-Coronilletum repandae, Sileno coloratae-Ononidetum variegatae cutandietosum maritimae). The surveyed associationsare ascribed to the following orders: Cutandietalia maritimae (annual associations of semi-fixed dunes) andMalcolmietalia (inland sandy soil communities). Moreover, for this latter order, a new alliance, Filagini asterisciflorae-Linarion humilis, that groups the therophytic communities from fossil dunes and deep sandy soils of the inland of theSicily, is proposed. Another aim of this study is to check and compare the discrete model of plant community against thecontinuum model along environmental gradients.