Rubble Biodiversity Samplers (RUBS): 3D-printed coral models to standardise biodiversity censuses

1. To ensure standardised, quantitative and repeatable methodologies,
marine ecologists have engineered a range of artificial units to survey
benthic communities with varying designs depending on target taxa, life
history stage and habitat. In tropical ecosystems, autonomous units have
typically lacked microhabitat complexity (e.g. planar tiles), short-term
efficacy (> 1 y deployment) and/or a truly standardised design to
sample cryptobenthic diversity. 2. Coral rubble is characterised by high
microhabitat complexity, which is unresolved in sampling efforts. Yet,
rubble can support the greatest density and diversity of metazoan taxa. 3.
We engineered Rubble Biodiversity Samplers (RUBS) as a dismantlable
lightweight 3D-printed model to standardise cryptobenthic biodiversity
sampling. 4. We demonstrate the effectiveness of RUBS with preliminary
results from short-term (1–14 days) deployments in Palau, Western
Micronesia. 5. RUBS uphold the microhabitat complexity inherent in coral
rubble (~50% interstitial space) and provide an effective and efficient
methodology to sample cryptobenthic fauna, which could be applied in
comparative studies. 6. The RUBS concept provides a platform for the
broader implementation of 3D-printed models in marine ecology to overcome
issues of standardisation regardless of habitat type.