Scleractinia corals of Baa Atoll (Maldives): first checklist and overview of stony corals community structure

Abstract

A survey of scleractinian corals for 21 stations in Baa Atoll (Republic of Maldives) was conducted in June 2009. The goal of the survey was to i) compile for the first time for this atoll a scleractinian coral check-list, ii) estimate the atoll total richness, iii) estimate intra-atoll richness variation and iv) describe preliminary patterns of community structure according to geomorphology and location criteria. The survey was stratified by the main reef geomorphological units. A total of 173 species of scleractinia belonging to 49 genera were recorded, including several species new to Maldives. Conversely, a number of species of genera quite common in the Indian Ocean were absent of the list of Pocilloporidae. Average richness per station was nearly 60 species. Richness ratio between slopes and flats/tops were between 3 and 1.3, with an average of 2.1, highlighting richer slopes than flats and tops. Differences of community composition between geomorphologic strata and between oceanic/lagoonal reefs were significant. Central lagoonal reefs provided highest richness, and highest coral cover as well. These findings are critical to plan for the conservation of Baa Atoll biodiversity.