Are available vegetation data suitable for assessing plant diversity? A study case in the Foreste Casentinesi National Park (Italy)

This paper aimed to analyze potentials and shortcomings of existing vegetation data collected in an Italian National Park (Foreste Casentinesi NP) to: (1) assess coarse scale patterns of species diversity, and (2) set up a habitat monitoring system. We generated a specifically designed georeferenced dataset by assembling all available forest vegetation data, and then we analyzed spatial and temporal patterns of data by sample-based accumulation and rarefaction curves. The analyses were performed on data gathered from the year 1934 to 2007. This broad temporal range may provide valuable information about processes occurring over a longer period than the majority of the published resurvey studies. Our study revealed an uneven distribution of the records both in time and space, corroborating the view that this type of data is inappropriate to analyze trends of plant diversity at coarse scale. However, especially the oldest records of the dataset represent a valuable source of information about long-term plant diversity changes, if used in resurvey studies designed with proper techniques. Detecting the directions of vegetation, or habitat, dynamics is crucial for addressing effective conservation actions.