Diversity and spatial patterns of plant communities in volcanic temporary ponds of Sicily (Italy)

The results of a study on plant community diversity, floristic richness, and spatial patterns in volcanic temporary ponds of Sicily are presented. A total of 166 plots were analyzed, 103 for Etna and 63 for Hyblaean sites. For each plot, the floristic composition and species cover were determined using standard relevé methods. Moreover, for these ponds, pH, conductivity, temperature, rainfall, altitude, and a floristic richness and diversity index were assessed. The plant communities were analyzed using a hierarchical cluster analysis, while the ordination method Non-metric Multidimensional Scaling was used to establish spatial patterns in the scattergram and to generate hypotheses on the vegetation/environment relationships. A total of nine plant communities for Hyblaean and seven for Mount Etna with a specific floristic composition were recognized. The spatial patterns of plant communities mainly followed an ecological gradient related to hydroperiod of the ponds, as well as local topography and human activities. The results show a considerable difference in floristic richness between the two study areas, as well as a different distribution of the life forms. Furthermore, for each study area the floristic richness and diversity index increased from the deep zone towards the shallow zone.