Long-term dynamics of a freshwater sponge population

1. Quantitative field data were collected from a Sardinian population of the sponge Ephydutia fluvtatilis from 1987 to 1993 in order to study its life style. 2. Growth of sponges was high during the annual cycle, and showed few changes in 6 years. Gemmulation was very rapid and highly efficient. Life spans of many specimens extended up to 5 years. 3. The population was destroyed by one flood during our study period. The persistence of gemmules on substrata suggested that dispersal was low in our study population. Recolonization started 7 months after the flood and re-established a new population, different from the previous one in terms of spatial structure and specimen size.