Phylogenetic measures of biodiversity uncover pteridophyte centres of diversity and hotspots in Tuscany

Biodiversity studies traditionally use species as their analysis unit. However, observed biodiversity is not necessarily an indicator of significant biodiversity and therefore, should not be used alone, particularly when the results will be employed for conservation planning. Here, we examine pteridophyte diversity in Tuscany using 4668 geo-referenced pteridophyte records stored in Wikiplantbase #Toscana and calculating standard richness measures and phylogenetic indices; in addition, we assessed the environmental predictors of each diversity metric. Finally, we identified which areas hosting significantly high diversity are not adequately covered by protected areas or intersected by human activities. Although considerable diversity is distributed along Tuscany within areas traditionally recognised as biodiversity hotspots, important areas of diversity are identified only after the application of randomisation tests and through the phylogenetic metrics. Topographic ruggedness resulted the single most important variable predicting high value of all indices; temperature seasonality and temperature continentality resulted the secondary explanatory variables with a significant negative effect on most diversity indices.