Replacement of the compound ascidian species in a southeastern Brazilian fouling community

Abstract

The replacement of compound ascidians on two series of ceramic plates (225 cm²) has been studied for nine months in the São Sebastião Channel. One of the series was initiated in the summer and the other in the winter. Five species were the most abundant and frequent on the plates. Diplosoma listerianum (Milne-Edwards, 1841) and Symplegma brakenhielmi (Michaelsen, 1904) showed the higher percent values of cover in the beggining of succession. Although Didemnum speciosum (Herdman, 1886) recruited in high numbers, its cover was only important after some months because of its slow growth rate. Clavelina oblonga Herdman, 1880 was a typical late successional species with low recruitment intensity and slow growth rate, and Botryllus niger (Herdman, 1886) was characterized by its constant appearing and disappearing. The overgrowth between ascidian species was not seen and it seems probable that the replacement of species was related to the death of early colonizers that presented a shorter life span.