Spatial and environmental drivers of vascular plant richness across the islets of Sardinia

Islands have often been considered as “natural laboratories” for studies on the biology, ecology, and genetics of plant species. Although, distribution patterns of vascular flora of Sardinia (second largest island of Mediterranean Basin), and its 261 circum-Sardinian islets, have been poorly investigated. We focused our research on distribution of the vascular flora in all the islets around Sardinia; besides all common island species–area relationship (ISAR; including choros) functions, the correlation between total vascular flora/endemic richness and geographic, topographic, climatic and anthropic drivers have been analyzed. A total of 81 islets hosted endemic plants; all ISAR functions showed significant correlations but the responses of endemic richness were higher influenced by elevation, distance from the main island and human disturbances than total richness. Our study provided new insights into the small Mediterranean island biogeography, useful for future conservation activities.