Literature review of coral reef restoration in and around the coral triangle from the viewpoint of marine biodiversity

Abstract

The coral reefs of the Coral Triangle and nearby marine regions are the most biodiverse marine ecosystems in the world, providing ecosystem services to hundreds of millions of people. However, like coral reefs in other regions, these ecosystems are in decline due to a myriad of anthropogenically-induced stressors. To mitigate this decline, active coral reef restoration efforts have been increasing worldwide, including in this region. An important end-goal of coral reef restoration is the conservation of functional biodiversity of not only zooxanthellate scleractinian corals, but of all associated coral reef organisms. In this literature review, we collected papers from the Web of Science (1995- 2021) focused specifically on coral reef restoration from six countries and regions around the Coral Triangle (Japan, Taiwan, mainland China, the Philippines, Malaysia, Indonesia) to examine how much coral reef restoration research has been performed in each area, when it was performed, what methodologies were used, what organisms were targeted, and whether any assessment of biodiversity was included. Our results show great disparity in the research efforts of each area, with the Philippines clearly leading research in the region with almost half of the literature examined, followed by Japan and Indonesia, with nascent efforts in mainland China, Taiwan, and Malaysia. Overall, for the region, research appears to be increasing with time. Research in most areas was concentrated in one or two locations, and almost exclusively focused only on corals. Only approximately 38% of papers mentioned biodiversity in any manner, and only 14% included organisms other than scleractinian corals in their results. It is clear from this review that extensive research and data gaps exist regarding coral reef restoration in the western Pacific and Coral Triangle, particularly from the viewpoint of biodiversity. It is hoped that research can address these gaps before coral reef ecosystems in the region decline even further.