Preliminary evidence of early Reef Cube^® enhancements to mobile benthic ecosystems

Abstract

Reef Cubes® are ecological engineering units, intended to restore biodiversity while serving functions to marine engineers. Ecological engineering must be backed by quantitative scientific evidence. Here, preliminary results of the Reef Enhancement for Fisheries at Aquaculture Sites (REFAS) project are presented. 11 Clusters of Reef Cubes® were deployed in June 2021. Sampling was undertaken before and after in the Spring and Autumn of 2021, in daylight and at night-time. Guided Baited Remote Underwater Video Station (BRUVS) surveys were completed with a modified BlueROV2. All mobile benthic and demersal species were identified during a 30-minute window and quantified in terms of Max-N. Biodiversity indices, rarefaction curves and multivariate community compositions were compared at reef and non-reef sites before and after build. Average species richness, Pielou’s evenness, Simpson’s and Shannon’s indices were similar between reef and non-reef sites. Seasonal increases of total abundance and total species were found, and these were significantly greater at reef sites. There were also significant differences in the community compositions of the reef and non-reef sites that were not observed before the build. These results are significant for the implications of using Reef Cubes® and indicate that Reef Cubes® could be a potential tool for biodiversity remediation.