Diversity of Molluscs Associated with Mangrove Vegetation in the Mangrove Forest Perancak Jembrana Bali

This study aims to analyze the diversity and association of molluscs in the Perancak Jembrana mangrove forest habitat. The study used the square method. A total of 30 squares were carried out in three mangrove forest zones (land zone, middle zone and estuary zone). Species diversity was analyzed using the Shanon-Wiener index. The association of molluscs with mangrove vegetation was analyzed using the 2x2 contingency table method. The use of mangrove vegetation strata was analyzed using Detrended Correspondence Analysis (DCA). The results of the study found 14 species of molluscs from the Gastropoda class which are included in five families and one species from the Bivalvia class. The most dominant mollusc species include Littorina scabra, Terebralia sulcata, Littoraria carinifera and Cerithidea obtusa. The mollusc diversity index is 2.39, the evenness index is 0.86, this indicates that the condition of the Perancak mangrove forest is in the stable category. Several mollusk species show high association properties with mangrove plant species, namely Nerita lineata - Rhizophora mucronata, Nerita lineata - Sonneratia alba, Cassidula nucleus - Rhizophora mucronata, Cassidula nucleus-Rhizophora mucronata, Littorina scabra-Avicennia lannata, Littorina scabra - Xylocarpus granatum, Littorina sp.- Avicennia lannata, Littorina sp.- Sesuvium portulacastrum. Mollusc species that strongly use strata I (substrate) are Cerithidea cingulata, Nassarius dorsatus, Littorina sp., Cassidula aurisfelis, commonly use strata II (mangrove roots) and strata III (mangrove stems) are Ostrea edulis, Cassidula mustelina, Terebralia sulcata, Cerithidea obtusa, Nerita lineata and molluscs are strongly associated with strata IV (mangrove leaves), namely Littoraria carinifera, Littorina scabra, Littorina undulata.