Coral reefs are highly productive, biologically diverse ecosystems, that support an assortment of marine organisms and provide many ecological goods and services to local and surrounding coastal populations. The reef flat is a delicate coastal habitat that faces vulnerability to influences such as coastal runoff and development, sedimentation, overharvesting, increased temperatures, and other effects of climate change. Precise, effective, and repeatable assessments of reef flat habitat dynamics are pivotal for the mapping, monitoring, and conservation efforts aimed at preserving these distinctive environments.

The overall aim of this research was to investigate the ability of Unoccupied Aerial Vehicle (UAV) Full Motion Video (FMV) techniques to effectively quantify the dynamics of habitat zonation across the Vavanga reef flat on Kolombangara Island, Solomon Islands. This study combined UAV footage with synchronous underwater video within ArcGIS Pro, to map the distribution of substrata and biota across the reef flat at multiple classification levels.

Many patterns in the distribution of substrata and biota were illustrated in this study, through a combination of summary statistics, simple linear regressions, and classification and regression trees. Additionally, the classifying ability of the image recognition software ReefCloud.AI was found to be moderately successful when applied to a subset of the collected data. An Object-Based Image Classification (OBIA) was also performed across a section of the high-resolution photo orthomosaic and resulted in variable classification accuracies across the selected classes.

The combination of synchronous UAV FMV and underwater imagery successfully achieved the anticipated outcomes of the project, yielding precise images, maps, and statistical models of the subtidal area. This innovative approach has a broad range of potential applications and has contributed to the development of effective subtidal surveying and mapping techniques. These advancements will enhance our ability to make informed decisions around ecosystem-based management and the conservation of globally threatened coral reef ecosystems.