A review of autonomous reef monitoring structures ( <scp>ARMS</scp> ) for monitoring hard‐bottom benthic biodiversity

Abstract Amid increasing anthropogenic pressures on ecosystems, standardised biodiversity monitoring is critical for assessing biodiversity change. Marine hard‐bottom habitats, though ubiquitous and biodiverse, present challenges for biodiversity monitoring due to their complex structure and limited accessibility. Autonomous reef monitoring structures (ARMS) have been developed to standardise marine hard‐bottom biodiversity monitoring across sites and research groups. This review analyses the methodological approaches utilised to date, spatial distribution, and temporal coverage of ARMS research across 49 publications. Variation in deployment, retrieval, replication strategy, and processing of ARMS was observed, presenting a barrier to study interoperability. Spatial coverage is biased to coral reef ecosystems and the Northern Hemisphere but is expanding globally. Irregular deployment timing and overall deployment durations constrain temporal coverage across sites and biogeographical regions, with few studies exploring the influence of deployment timing and duration on ARMS' community composition. Genetic methods, namely, DNA barcoding and metabarcoding, dominate community composition analyses but there is significant variation in methods of DNA extraction, PCR protocols, target genes, sequencing platforms, and bioinformatic pipelines. Furthermore, images of ARMS' plates are an underutilised resource for biodiversity investigations and rarely used in conjunction with genetic analyses. This review highlights the need for greater standardisation and reporting consistency in ARMS research to improve study interoperability and reproducibility to enable global biodiversity monitoring in our changing world.