Deriving a habitat quality index to inform reef conservation in the Great Barrier Reef

Details

Supervisors

Hanert, Emmanuel ; Saint-Amand, Antoine

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences et technologies de l'environnement

Abstract

The Great Barrier Reef, as the world’s largest coral reef ecosystem, is an exceptional site of global importance. Unfortunately, after thousands of years of existence, this wonderful biodiversity place, which shelters no less than 600 coral species and 1600 fish species, is under severe threats. The main threat is climate change. It induces a rise in seawater temperature which causes bleaching events. In addition, we are witnessing an increase in the frequency of destructive tropical cyclones. Human activities along the coasts bordering the GBR are also responsible for the degradation of this vast marine ecosystem. Agricultural activities discharge many pollutants into the ocean that degrade water quality. The many COTS outbreaks that ravage some reefs are also a significant concern to be considered. The aim of this thesis is to develop indices to understand, identify and quantify the main threats. First, single-threat indices are developed for each of them. Those indices have been designed to provide an estimate of coral cover loss. Then, we combine them to obtain a global reef-level habitat quality index for the entire GBR. The contribution of each threat in the global index will be deduced from coral cover data. The habitat quality index can be used to improve estimates of connectivity between reefs to obtain a closer-to-reality connectivity. Most of the indices presented in this thesis have the advantage of giving an annual indication of the impact of the threats. They therefore allow us to monitor the evolution of the state of the GBR. This could help decision-making, particularly for the creation of protected areas.