La flora legnosa dell’Italia centrale. Analisi lungo un gradiente longitudinale

A key problem in quantifying biodiversity is whether it is possible to infer overall diversity using suitable data subsets. The aim of this paper, based on updated data on the native woody flora of Italy, is to evaluate the reliability of such data as a predictor of vascular plant richness at a medium scale represented by the 20 administrative regions. Woody taxa were divided in trees, shrubs and lianas. We used stepwise multiple regression and principal component analysis to analyse the correlation between environmental heterogeneity, vascular plant units (species and subspecies) richness and woody units richness. Woody flora of Italy consists of 61 families, 133 genera, 469 species, 509 units. Shrubs constitute 74% of the woody flora, trees and lianas 23 and 3% respectively. Both stepwise multiple regression analysis and two principal component analyses strongly suggest that woody units, and trees in particular, are correlated with total vascular plant richness, at all hierarchical taxonomical levels. The environmental heterogeneity has been demonstrated to be much more important than the area for the Italian regions biodiversity. Woody flora, as a surrogate of total flora, is extremely useful for rapid assessments of overall vascular plant diversity that may be exploited for monitoring purposes.