The functional approach in the analysis of herbaceous communities: an example from highly biodiverse Prealpine grasslands.

The functional approach for community description and analysis is now widespread among plant ecologists. Functional analysis has a key role at different levels, as shifts in functional traits that currently result from changes in climate, soil and/or management, have predictable effects in rates and magnitudes of ecosystem processes. Moreover, plant functional types represent a useful means to deal with communities characterised by high species diversity, and could be fundamental in conservation ecology and community management. A functional investigation was performed on calcareous grasslands from Monte Barro, a small mountain in Lombard Prealpine District. Plant attributes for several vegetative traits were gathered on 151 species from field and laboratory measurements. Ordination (PCA) and fuzzy clustering then led to species allocation to plant strategies according to Grime’s C-S-R triangular scheme (GRIME, 2001). According to the results of multivariate analysis, two main axes of variation act among species from Prealpine calcareous grasslands, the first one referring to competitive ability and the second one to effective resource use. As to the functional characterisation of the examined communities, species mainly belong to stress-tolerant strategy, while ruderality is almost not represented. A clear pattern of variation in strategy distribution among vegetation types was recorded by plotting different grasslands along possible light/soil moisture gradients: increase in nutrient and water availability is related to a reduction in the stress-tolerant species while competitors increase, with a consistent progressive decrease in species number.Moreover, a strong association between functional types and species richness was recorded, as the communities with the highest species number were also characterised by the most even distribution of different strategies.