ZOOPLANKTON COMMUNITIES IN TWO ASTATIC BASINS IN THE NATURAL RESERVE OF CASTELPORZIANO (CENTRAL ITALY): COMPOSITION AND TEMPORAL SUCCESSION

The composition and temporal succession of the zooplankton communities in two neighboring biotopes (a permanent pond, P17; the latter exhibited more stable environmental conditions. A total number of 52 taxa was collected, of which only 20 were shared by both ponds. In spite of its harshness, T17 had a richer and more diversified zooplankton than P17, suggesting an important role of the dry phase in determining such conditions. Substantial differences in temporal succession of zooplankton were apparent for T17, in which distinct successional phases were identified on the basis of diversity and exclusiveness of the taxa present. This composition and structure seemed to be strongly linked to the long-lasting wet phase.; and a temporary pond, T17) in the natural reserve of Castelporziano (Central Italy) were investigated for one year. Along with some physicochemical parameters (pH, dissolved oxygen, conductivity), the relative abundance of major zooplankton groups, species composition, and community structure (i.e., species richness, Shannon diversity, and evenness) of both ponds were compared. Almost all the parameters considered showed greater variations in T17 than in P17