The Italian endemic forest plants: an annotated inventory and synthesis of knowledge

Background and aims – Forests are among the most threatened ecosystems worldwide, and endemic plants are often a vulnerable component of the flora of a given territory. So far, however, understory forest endemics of southern Europe have received little attention and are poorly known for several aspects. Material and methods – We developed the first list of native vascular plants that are restricted to Italian forests. Available information on taxonomy, regional distribution, ecology, biology, functional traits, and conservation status was collected for each taxon, allowing to identify major knowledge gaps and calculate baseline statistics. Key results – The list includes 134 taxa, most of which are linked to closed-canopy forest habitats, while the others are also found in margins and gaps. The forest and non-forest Italian endemic flora differed in terms of taxonomic and life-form distribution. The rate and density of forest endemism increased with decreasing latitude and were highest in Sicily, Calabria, and Basilicata, where paleoendemic mono- or oligotypic genera also occur. Endemic phanerophytes were especially numerous on islands. Beech and deciduous oak forests were the most important habitats, but hygrophilous woodlands also host numerous endemics. Overall, the ecology, biology, and functional traits of the forest endemic taxa are still poorly known. The ratio diploids/polyploids was highest in the south and on the islands. Almost 24% of the taxa were assessed as “Critically Endangered”, “Endangered”, or “Vulnerable”, and 24% were categorized as “Data Deficient”, based on the IUCN system. Increasing frequency and intensity of fires was the most frequent threat. Conclusions – This work can contribute to implement the European forest plant species list and serve as a basis for further research on a unique biological heritage of the continent. However, more knowledge about these globally rare taxa is needed, to support their conservation in changing forest landscapes.