Biodiversity in mediterranean temporary ponds: contrasting space/time patterns among multiple organism-groups

The effectiveness of surrogate taxonomic groups approaches in addressing conservation programs and setting out priority areas for conservation has been widely debated in the last decades. In this sense we evaluated the congruence among spatial and temporal biodiversity patterns of five groups of fauna and flora of a European protected habitat as Mediterranean Temporary Ponds (MTP). The three objectives of the study were: (1) to identify the main source of variability of the biodiversity of each fauna/flora group; (2) to compare the temporal patterns of biodiversity among fauna/flora groups; and (3) to identify crosstaxon congruence in biodiversity parameters. The five groups of organisms incorporated in this study present different capacity to respond to environmental changes and different dispersion capacity (macrofaunal active and passive dispersers, microcrustaceans, macrophytes and microalgae). They were sampled simultaneously three times throughout the hydroperiod in six MTP located in Sardinia. The biodiversity parameters used in this study were: Species richness, Variation in taxonomic distinctness, Average taxonomic distinctness, Index of Faunal Originality, and Shannon-Wiener diversity. We performed a variation partitioning for each biodiversity parameter of each organism group in order to find its relationship with water, landscape and pond characteristics. We also compared the temporal variability of the biodiversity values for each flora/fauna groups. Finally, we established the relationships among biodiversity parameters by means of a PCA analysis. Our results suggest a lower importance of landscape characteristics for active dispersers than for passive ones. Moreover, no variability explained by the pure effect of pond and landscape variables was observed for the macrofaunal active dispersers, whereas these two categories explained a significant proportion for the other groups.