Assessing the impact of acute disturbances on the structure and composition of a coral community using innovative 3D reconstruction techniques

Loss of live coral and declines in the structural complexity of reef habitats affects ecosystem-level processes such as energy flow, nutrient cycling, and community dynamics. Scleractinian corals are the primary contributor to the biological and physical three-dimensional (3D) structure of coral reef ecosystems. Disturbance events that induce coral mortality can alter the 3D structure of reefs habitats and lead to disruptions in trophic structure and organismal relationships that drive ecological processes. The coral reef ecosystem at Wai'ōpae, southeast Hawai'i Island, experienced several acute disturbance events in 2014, including a hurricane, tropical storms, and a severe coral bleaching event. This study utilized innovative 3D reconstruction techniques to create high-resolution models of the coral reef habitat and quantify structural metrics known to affect the biodiversity and abundance of associated reef organisms. A volumetric analysis was applied to the reconstructed 3D point clouds to determine the precise loss of habitat that occurred throughout the surveyed reef area. Conducting a temporal analysis using 3D reconstructions enabled us to test the hypothesis that volume and 3D architectural complexity of the coral community at Wai'ōpae was significantly impacted by the acute disturbance events.