The coral reef communities at Saint-Gilles la Saline in 1987 (Reunion Isl., S.W. Indian Ocean).

Odile Naim (1)

1 ECOMAR - Laboratoire d'Ecologie Marine

This study documents the structure of benthic communities on the Saint-Gilles La Saline coral reef flat, the most highly evolved fringing reef of Reunion, a high volcanic island belonging to the Mascarene Archipelago. A total of 17 radials and 169 line transects were surveyed along the 9-km-long reef flat. A phytosociological classification based on the algal and hard coral dominance, and a "Principal Component Analysis" (PCA) based on substrate categories and densities of echinoderms and Stegastes (sedentary fish species) both opposed two types of benthic communities (1) a first one dominated by a living and diverse Acropora community (mainly A. formosa and A. humilis with inconspicuous coverage of fleshy algae and high densities of sea-urchins (Echinometra mathaei and Diadematidae) on the reef flat, here named ACR, and (2) a second one (MAS) consisting of a submassive coral community (mainly Montipora circumvallata and Porites (Synaraea) rus) in competition with abundant fleshy algae and cyanophytes, with a few sea-urchins on the reef flat and high densities of holothuroids (mainly Holothuria atra) on the back reef. The ACR community is considered here to be the community in climax, while the MAS community, less abundant, is hypothesized to be the structure degraded by a dystrophy of the system.

Mots clés: South-west Indian Ocean; Reunion island; coral reefs; fringing reefs; reef flats; benthic communities; corals; algae; sea urchins; holothurians; autotrophy; heterotrophy; degradation; eutrophication

Domaines: Biodiversité et Ecologie

Odile Naim. The coral reef communities at Saint-Gilles la Saline in 1987 (Reunion Isl., S.W. Indian Ocean).. The Journal of Nature (Bourbon Sciences), 2006, 18 (1), pp.13-33. ⟨hal-00764600⟩