Studies on littoral and sublittoral macrophytes around the Mauritius coast

Abstract

Floristic composition from the intertidal lagoon, reef, and subtidal (down to 20 m depth) regions, around the mauritius coast were studied to assess its present status. This provides firsthand information on the ecological distribution of mangroves, seagrasses, and subtidal marine algae. The marine flora was representEd. by 127 species of seaweeds, five species of seagrasses, and 3 species of mangroves. The greatest number of species and biomass of marine algae occurred in the intertidal and the lagoonal zones. Only a few species of seaweeds, such as Asparagopsis taxiformis, Halimeda spp, Turbinaria ornata, and coralline algae, were associated with corals in the subtidal regions. The most widely distributed marine algae were Ulva spp., Enteromorpha kylini, Cladophora saviniana, Boodlea composita, Sargassum binderi, Turbinaria ornata, Gracilaria salicornia, Hypnea cornuta, Digenea simplex and Laurencia papillosa. The mangroves were mainly restricted to the northeast and east coasts and Rhizophora mucronata comprises almost 100% of the vegetation. The small patches of seagrasses such as Halophila ovata, Halodule uninervis, and Syringodium isoetifolium occurred commonly in patches in the lagoons towards the northeast and east. The poor representation of marine algae and seagrasses reflects the degradation of the marine ecosystem. The steep slopes and small tidal amplitude, have resulted in the formation of fringing mangroves along the coast