The impact of cyclonic activity during 1981-1985 and 2004-2009 on taxonomic diversity of mollusks in the Gulf of Batabanó, Cuba

The cyclonic activity within the Gulf of Batabanó has been historically documented and, in the past two decades, it has been possible to observe signals of environmental degradation in its physical and biological state. Yet a study aimed at evaluating the effects of cyclonic activity on the taxonomic diversity of mollusks has not been made. The objective of this study was to evaluate the effects of cyclonic activity during 1981-1985 and 2004-2009 on the taxonomic diversity of soft-bottom mollusks of this region. To measure the cyclonic activity, the Power of Dissipation Index for hurricanes (PDI) was used. The average taxonomic distinctness index (Delta+) and the variation in the taxonomic distinctness (Lambda+) of the inventory of the mollusks species for both periods were used as a measure of taxonomic diversity. We detected high cyclonic activity (HCA) during 2004-2009 and low cyclonic activity (LCA) during 1981-1985. The taxonomic composition during both periods was made up of 3 classes, 20 orders, 68 families, 155 genus, and 208 species. Significant differences in the taxonomic composition between the two periods were detected, due principally to the loss of genus and species. The taxonomic distinctness index reveals significant changes of the taxonomic structure of mollusks during 2004-2009, which is related to a rise in cyclonic activity. These results suggest that the taxonomic diversity of mollusks was less complex during 2004-2009 than during 1981-1985.