Geographical and ecological differentiation in Italian mesophilous pastures referred to the alliance Cynosurion cristati Tx. 1947
Blasi, C.; Tilia, A.; Rosati, L.; Del Vico, E.; Copiz, R.; Ciaschetti, G.; Burrascano, S.
The alliance Cynosurion cristati has been found by various authors across the European continent. However, the fact that its diagnosis is based on species that are found in a wide range of geographical and ecological conditions and on the absence of grazing-sensitive species has rendered the characterization of this alliance somewhat complicated. The aims of this paper were: i) to investigate differences in the composition of some European mesophilous pastures, with particular focus on Italy; ii) to assess the main factors underlying these changes; iii) to evaluate the need for a new classification for such communities in the Italian peninsula. We used previously published data from several other European countries and both published and unpublished data from Italy. A synoptic table of data from different parts of Europe was analysed by means of hierarchical clustering. We used Multi-Response Permutational Procedure and phi coefficient to test differences between Cynosurion clusters and identify their diagnostic species. We performed Non-metric Multi-Dimensional Scaling on a table of 111 Italian relevés. Kendall’s correlation coefficient was calculated by relating the relevé scores in the ordination with the geographical, environmental variables, and with the Ellenberg indices relative to soil conditions. The first axis scores were also used as the dependent variable in a regression tree. Important compositional differences were found within the Cynosurion cluster, with significant differences emerging between the Apennine pastures in central and southern Italy and those in northern and central Italy. The first axis ordination was strongly related to the latitudinal/thermal gradient. Indeed, latitude and temperature were the most important variables in the regression tree. Our results highlight marked compositional variation in Cynosurion grasslands. This variation, which is related in the Italian peninsula to bioclimatic and biogeographical factors, led us to propose a rearrangement of the existing classification of the alliance for this part of Europe.