VIOLA - The vegetation database of the central Apennines: Structure, current status and usefulness for monitoring Annex i EU habitats (92/43/EEC)

In this paper we describe VIOLA (VegetatIOn of centraL Apennines), a database of high mountain vegetation relevés in the Central Apennines (Italy). We explore the general features of the data collected, specifically the variation in plot size, time range of the relevés and geographical position accuracy. VIOLA gathers a representative number of relevés from 7 Annex I habitats sensu Habitat Directive (92/43/EEC) (4060, 4070∗, 6170, 6210, 6230∗, 8120 and 8210). We characterize the dataset in terms of the total number of relevés, the total number of species, the most abundant species, the total number of endemics, the total number of phytosociological alliances and the most abundant alliance. For each habitat, life form and chorotype spectra were also calculated using the species frequency. In total, we collected 1,687 relevés including both published and unpublished phytosociological information collected above an altitude of 1,600 m a.s.l. in the Central Apennines (Gran Sasso, Majella, Monti del Matese, Monti della Meta and Velino massifs). The oldest relevés back to 1955, whereas the newest ones to 2014. A total of 45% of the relevés were recorded with the exact GPS coordinates, and 55% were referred to general description of the localities (toponyms); most of the relevés (77.8%) are between 10 and 100 m2 wide. The Alpine and subalpine calcareous grasslands (6170) and the Calcareous and calcshist screes (8120), with over 50% and almost 20% of the relevés, respectively, are the most represented Annex I EU habitats in the database. Our results highlight that the stalked hemicryptophytes and Southern Europe Orophilous dominate in all EU habitats. Endemics are present in all habitats but higher percentages occur in Calcareous and calcshist screes, followed by Calcareous rocky slopes and Alpine and subalpine calcareous grasslands. Based on our results, we can confirm the value and usefulness of large vegetation databases for supporting theoretical and applied vegetation and ecological studies at different scales.