Succession patterns in algal turf vegetation on a Caribbean coral reef

Over the past three decades, Caribbean coral reefs have drastically changed in structure and organization due to anthropogenically driven environmental changes. The prognostic trend indicates a shift from coral- to more algal-dominated reefs coupled with a loss in biodiversity and destabilization of reef structure. This study focuses on the composition of the most common algal growth form, the turf, and investigates turf succession within a fringing Caribbean coral reef. In a field study starting October 2007, we followed succession of turf algal assemblages grown on artificial substrata for periods of 15 up to 333 days at different water depths (5, 15 and 25 m). Species composition and abundance, biodiversity, total cover, and biomass were investigated and compared in uni- and multivariate analyses. Despite the pronounced change in coral reef structure over the past years, we found little difference from primary succession patterns described 30 years earlier. Succession patterns revealed a high diversity, mainly driven by the filamentous brown algal order Ectocarpales, the crustose green alga Pringsheimiella scutata at early stage, and diverse filamentous Cyanobacteria at later stages. Overall, the study provides insight into the early successional stages of coral reef vegetation by identifying the key species and discussing possible factors determining reef development in relation to environmental change.