Smithsonian Marine Science Symposium

Registration

VENUE INFO

Agenda

Speakers

Home

Abstract

BIODIVERSITY AND ABUNDANCE OF SPONGES ON CARIBBEAN MANGROVE ROOTS

M. Cristina Diaz¹ and Klaus Ruetzler²
¹Museo Marino de Margarita, Venezuela,
²National Museum of Natural History
Bio

Surveys of diversity and abundance of sponges in Caribbean mangroves were carried out between 2003 and 2007 with support of the Marine Science Network program. The results show that sponges are an important component of the red-mangrove (Rhizophora mangle) root epifauna, both in species richness and relative abundance. Sixty-five species were reported from Bocas del Toro (Panama) and 62 from Twin Cays (Belize) mangrove habitats. Three new Haplosclerida species with unusual (filamentous) cyanobacterial symbionts were discovered (genera Haliclona and Xestospongia) and are currently being described. Field guides for each fauna are being produced with the aim of facilitating the study of marine sponges by non-experts. A comparison of mangrove species composition from Bocas del Toro and Twin Cays shows a high similarity with other well studied Caribbean sites, such as Venezuela (65 species) and Cuba (43). However, since most Caribbean mangrove systems have not been rigorously evaluated taxonomically, a conclusive biogeographic analysis can not yet be attempted. The distribution of sponge species within each studied geographic region indicates that the majority (50-80%) presents a disjunct distribution, being restricted to one or a few sites within a particular locality. The relative abundance of major epibenthic taxonomic groups (such as, algae, cyanobacteria, ascidians, sponges, bivalves) shows great variations in both space (between localities of each region) and time (over the course of one year or more). Recommendations to be considered for future studies of mangrove sponges include, that surveys should cover long fringe distances to account for the disjunct distributions; and that ecological studies relying on abundance or changes in species composition should be based on one given locality and long-term because of large spatial and temporal variations in the relative importance of major taxonomic groups.