Differences between epiphytic assemblages on introduced Caulerpa taxifolia and coexisting eelgrass (Zostera capricorni) in Botany Bay (NSW, Australia)
Patricia Prado and Thierry Thibaut

A preliminary study was conducted to assess the potential effects of introduced Caulerpa taxifolia (Caulerpales, Chlorophyta) on the biodiversity and trophic functioning of seagrass systems in New South Wales, Australia. Epiphytic assemblages growing on fronds of C. taxifolia were compared to those on eelgrass Zostera capricorni (Aschers.) leaves in zones where both species were coexisting. The study was conducted at three shallow sites (ca. 1 m depth) in Botany Bay during austral spring. Assemblages on both C. taxifolia and Z. capricorni were dominated by epiphytic algae (ca. 65% of the total taxa) but results showed significantly greater numbers on C. taxifolia compared to Z. capricorni as well as important differences among study sites. n-MDS ordinations and PERMANOVA analyses confirmed the existence of significant differences in the assemblage compositions of C. taxifolia and Z. capricorni as well as differences between times and sites. SIMPER analysis showed that animal composition made a higher contribution to dissimilarities between habitats compared to epiphytic algae (36% vs. 23% respectively). In particular, filter-feeding organisms, associated with surfaces such as ascidians (5 taxa) and bryozoans (2 taxa) emerged as important contributing taxa. Hence, our results suggest that introduced C. taxifolia from Botany Bay is a suitable substratum for settlement of epiphytes, at least during the study period, and that observed patterns are due to differences in habitat structure. Further research is necessary to determine the influence of seasonal processes, such as production of toxic secondary metabolites, in other invaded locations of New South Wales.

Keywords: epiphytic assemblages, Caulerpa taxifolia, Zostera capricorni, richness of taxa, habitat complexity, New South Wales
Contents of this volume Sci. Mar. 72(4) : 645-654 Back PDF
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