Regulation of species richness by advection and richness-dependent processes in a coastal fish community

The WWF Oasis of Palo, 38 kms north of Rome, is one of the last remnants of the Mediterranean plain forest formerly covering the coastal areas of Latium. Within this preserved area, nine temporary waterbodies were periodically visited during 2001 to obtain information on their morphology, water cycle and faunal composition. In total, 25 crustacean species were listed and monthly changes in their abundance were recorded. Cladoceran species prevailed in all waterbodies (11 species, 7 genera, 2 families). Copepoda were represented by 8 species, 7 genera, 2 families. Ostracoda included 5 species, 5 genera, 3 families. Anostracans were recorded in only two pools and were represented by Chirocephalus diaphanus Prévost, 1803, the most common species in Italy. Chirocephalus kerkyrensis Pesta, 1936 usually occurring in the waterbodies of the Mediterranean maquis, was missing. Species richness was maximal in late autumn and winter, and correlated positively with pond duration, flooded area, water level and number of rainpools. The species most frequently recorded were Chydorus sphaericus O.F. Müller, 1785 and Daphnia curvirostris Eylmann, 1887 for Cladocera, Megacyclops viridis Jurine, 1820, Diacyclops bicuspidatus odessanus Shmankevitch, 1875 and Mixodiaptomus kupelwieseri Brehm, 1907 for Copepoda, Cyclocypris ovum Jurine, 1820 and Eucypris virens Jurine, 1820 for Ostracoda. Others, like Alona affinis Leydig, 1860, Ceriodaphnia pulchella Sars, 1862 (Cladocera), Macrocyclops albidus Jurine, 1820 (Copepoda), Herpetocypris reptans Baird, 1835 Fabaeformiscandona fabaeformis Fischer, 1854 (Ostracoda) were found in only one pool.