The RRAP Rubble Stabilisation R&D Subprogram was part of RRAP’s first R&D phase and investigatined methods to stabilise damaged reef surfaces where dead or degraded corals have become loose and unconsolidated rubble, preventing or slowing reef recovery.
Natural and man-made disturbances (for example, cyclones, ship groundings, crown-of-thorns starfish outbreaks or coral bleaching) can reduce functional and diverse coral reefs to fields of rubble, with an unstable and mobile surface. The lack of stability and frequent motion inhibits recruitment (settlement and regrowth) of young corals back onto reefs and hampers recovery.
Rubble stabilisation, as a reef restoration technique, is in its infancy.
It is also important to be able to identify coral reefs that can most benefit from restoration strategies: those most vulnerable to rubble formation, and those where prevailing wave regimes can make mobile rubble persist and hinder recovery.
Of interest is identifying reefs where rubble is most likely to be generated through cyclone disturbance, crown-of-thorns starfish outbreaks and/or bleaching events, each of which can generate different rubble volumes and characteristics. The project aimed identify where the hydrodynamic conditions can maintain or continue to mobilise rubble, preventing stabilisation and thus coral settlement and recovery.
Evidence was drawn from existing reef restoration activities to assess the effectiveness of rubble stabilisation on ecosystem recovery. The project ran an evaluation of the efficacy of at least one existing methodology under a range of physical conditions. The project also explored the potential of biogeochemical binding methods as a future prospect for rubble stabilisation at larger scales than currently economically feasible.
Drawing on the above outcomes, a dedicated package of rubble stabilisation guidance tools was produced (such as manuals, maps, and standing operating protocols) to assist reef managers to prioritise assessment of rubble stabilisation interventions and allow users to decide where stabilisation activities are likely to be both useful and feasible.
The project aimed to determine where rubble will be a persistent problem on the Great Barrier Reef, hindering recovery of the reef after storms, bleaching or crown-of-thorns starfish predation.
This project aimed to evaluate and test the efficacy of existing approaches to rubble stabilisation and explore new bio-geochemical-binding methods.
This project synthesised results of RRAP rubble stabilisation research and build new rubble stabilisation modelling and analysis tools and guidelines for local practitioners.
Ceccarelli, D. M., McLeod, I. M., Boström-Einarsson, L., Bryan, S. E., Chartrand, K. M., Emslie, M. J., Gibbs, M. T., Gonzalez Rivero, M., Hein, M. Y., Heyward, A., Kenyon, T. M., Lewis, B. M., Mattocks, N., Newlands, M., Schläppy, M.-L., Suggett, D. J., & Bay, L. K. (2020). Substrate stabilisation and small structures in coral restoration: State of knowledge, and considerations for management and implementation. PLOS ONE, 15(10), e0240846. https://doi.org/10.1371/journal.pone.0240846
Lewis, B. M., Suggett, D. S., Prentis, P. J., & Nothdurft, L. D. (2022). Cellular adaptations leading to coral fragment attachment on artificial substrates in Acropora millepora (Am-CAM). Scientific Reports, 12, Article 18431. https://doi.org/10.1038/s41598-022-23134-8
Kenyon, T. M., Mumby, P. J., Callaghan, D. P., Baldock, T. E., & Doropoulos, C. (2023). Coral rubble dynamics in the Anthropocene and implications for reef recovery. Limnology and Oceanography, 68(12), 2955–2969. https://doi.org/10.1002/lno.12254
Harris, D. L., Webster, J. M., Vila-Concejo, A., Duce, S., Leon, J. X., & Hacker, J. (2023). Defining multi-scale surface roughness of a coral reef using a high-resolution LiDAR digital elevation model. Geomorphology, 439, 108852. https://doi.org/10.1016/j.geomorph.2023.108852
Kenyon, T. M., Harris, D., Baldock, T., Callaghan, D., Doropoulos, C., Webb, G., Newman, S. P., & Mumby, P. J. (2023). Mobilisation thresholds for coral rubble and consequences for windows of reef recovery. Biogeosciences, 20(20), 4339–4357. https://doi.org/10.5194/bg-20-4339-2023
Kenyon, T. M., Jones, C., Rissik, D., Brassil, W., Callaghan, D. P., Mattocks, N., & Baldock, T. E. (2025). Bio-degradable ‘reef bags’ used for rubble stabilisation and their impact on rubble stability, binding, coral recruitment and fish occupancy. Ecological Engineering, 210, 107433. https://doi.org/10.1016/j.ecoleng.2024.107433
Kenyon TM, Eigeland K, Wolfe K, et al. Material Legacies on Coral Reefs: Rubble Length and Bed Thickness Are Key Drivers of Rubble Bed Recovery. Glob Chang Biol. 2024;30(11):e17574. doi:10.1111/gcb.17574
Deng, W., Kenyon, T., Eigeland, K., Callaghan, D. P., & Baldock, T. E. (2025). Structural and hydrodynamic modelling of the probability of breakage of branching and plate coral colonies. Coastal Engineering, 195, 104647. https://doi.org/10.1016/j.coastaleng.2024.104647
Liu, D., Callaghan, D. P., Wuppukondur, A., & Baldock, T. E. (2025). A probabilistic coral rubble mechanical instability model applied with field observations from the Great Barrier Reef. Coastal Engineering, 195, 104655. https://doi.org/10.1016/j.coastaleng.2024.104655
Kenyon, T. M., Mumby, P. J., Webb, G. E., Dove, S., Newman, S. P., & Doropoulos, C. (2025). Trajectories and agents of binding in stabilized and unstabilized coral rubble across environmental gradients. Ecosphere, 16(2), e70195. https://doi.org/10.1002/ecs2.70195
Liu, D., Callaghan, D. P., & Baldock, T. E. (2025). Accelerating coral rubble instability assessments with machine learning: Insights from the Great Barrier Reef. Applied Ocean Research, 158, Article 104580. https://doi.org/10.1016/j.apor.2025.104580
Liu, D., Callaghan, D. P., & Baldock, T. E. (2025). Quantifying the impact of future climate change on the risk of coral rubble instability across the Great Barrier Reef by 2100. Journal of Environmental Management, 386, Article 125716. https://doi.org/10.1016/j.jenvman.2025.125716
Cheung, Mandy W.M., Chaloupka, Milani, Mumby, Peter J., and Callaghan, David P. (2025). The spatial risk of cyclone wave damage across the Great Barrier Reef. Ecological Informatics 89 103175 103175-89. https://doi.org/10.1016/j.ecoinf.2025.103175
Deng, W., Kenyon, T., Eigeland, K., Callaghan, D. P., & Baldock, T. E. (2025). Structural and hydrodynamic modelling of the probability of breakage of branching and plate coral colonies. Coastal Engineering, 195, 104647. https://doi.org/10.1016/j.coastaleng.2024.104647
Lewis, B., Suggett, D., Prentis, P., Cooper, C., & Nothdurft, L. (2025). Asexual reproduction in reef-building corals: insights into fragment attachment to improve restoration and predict natural recovery. Royal Society Open Science, 12(10), Article 251209. https://doi.org/10.1098/rsos.251209
Deng, W., Simonnet, C., Nolan, L., Callaghan, D. P., & Baldock, T. E. (2026). Investigating coral rubble dynamics through tilting base and flume experiments. Coastal Engineering, 205, 104931. https://doi.org/10.1016/j.coastaleng.2025.104931
Kenyon, T. M., Eigeland, K., Richardson, M. A., Baldock, T. E., Wolfe, K. D., Sjahruddin, F. F., & Mumby, P. J. (2025). Threshold velocities for coral rubble bind breakage across varying reef environments. Marine Ecology Progress Series, 773, 1–16. https://doi.org/10.3354/meps14982
Kenyon, Tania M. (2021). From Rubble to Reef: The physical and biological dynamics of coral reef rubble beds. PhD Thesis, School of Biological Sciences, The University of Queensland.https://doi.org/10.14264/30ab794
Lewis, Brett. (2024) Substrate attachment in colonial Scleractinia. PhD thesis, Queensland University of Technology.
Baldock, T., Kenyon, T., Harris, D., Callaghan, D., Bryan, S.E., Lewis, B.M. and Mumby. P. (2025) Reef Restoration and Adaptation Program – Rubble Location, Prediction and Sub-program Management (RS-01) Final Report 2025. (21pp).
Bryan, S. E., Kenyon T. and Lewis, B. M. (2025) Reef Restoration and Adaptation Program – Approaches to Stabilisation (RS-02) Final Report. (23pp).
Leung, S., Kenyon, T., and Mumby, P. (2025) Reef Restoration and Adaptation Program – Synthesis, Intervention Tool and Guidelines (RS-03) Final Report 2025. (17pp).
| Title | Conference | Date |
|---|---|---|
| Turning rubble to reef: Quantifying rubble mobilisation and binding dynamics to assess recovery potential of disturbed reefs | 14th International Coral Reef Symposium (ICRS), Bremen, Germany | 2022 |
| Rubble in Focus: Examining characteristics and establishing a baseline for unconsolidated substrate across the Great Barrier Reef | Australian Marine Sciences Association (AMSA) Conference, Cairns, Australia | 2022 |
| A rubble persistance mapping on the Great Barrier Reef: hydrodynamic setting. | 10th World Conference on Ecological Restoration (SER2023), Darwin, Australia | 2023 |
| Cumulative bleaching undermines systemic resilience of the Great Barrier Reef | Asia Pacific Coral Reef Symposium (APCRS), Nus, Singapore | 2023 |
| Predicting coral rubble risk in the Great Barrier Reef | Asia Pacific Coral Reef Symposium (APCRS), Nus, Singapore | 2023 |
| Structural and hydrodynamic analysis of the breakage of coral colonies | Asia Pacific Coral Reef Symposium (APCRS), Nus, Singapore | 2023 |
| Hydrodynamic modelling on Heron Island to predict coral breakage and rubble motion | Australasian Coasts & Ports 2023 Conference, Twin Waters, Australia | 2023 |
| Bayesian network modelling for the Great Barrier Reef | Australia and New Zealand Industrial and Applied Mathematics (ANZIAM), Cairns, Australia | 2023 |
| Coral Recruitment in Rubble beds on Heron Island Reef | Australian Marine Sciences Association (AMSA) Conference, Gold Coast, Australia | 2023 |
| Let’s stick together: Rubble binding in the Indian and Pacific Oceans | Australian Marine Sciences Association (AMSA) Conference, Gold Coast, Australia | 2023 |
| Disentangling the complex and interactive coral bleaching drivers on the Great Barrier Reef | Coral Watch Bleaching Predictions and Solutions Webinar series | 2023 |
| Structural and hydrodynamic analysis of the breakage of branching and plate corals | 2024 International Conference on Coastal Engineering, Rome, Italy | 2024 |
| A deep dive into asexual reproduction using time-lapse and integrated 2D and 3D microscopy | Australian Coral Reef Society (ACRS) Conference, Perth, Australia | 2024 |
| Predicting the future risk of cyclonic wave damage across the Great Barrier Reef | Australian Coral Reef Society (ACRS) Conference, Perth, Australia | 2024 |
| Impacts of Tropical Cyclones over Australia. A Hazard Management Perspective | Australian Marine Sciences Association (AMSA) Conference, Hobart, Australia | 2024 |
| Implications of uncertainty in modelling the risk of coral rubble generation and persistence on the Great Barrier Reef | Australian Marine Sciences Association (AMSA) Conference, Hobart, Australia | 2024 |
| Opportunities and limitations to studying reef rubble with remote sensing | Australian Marine Sciences Association (AMSA) Conference, Hobart, Australia | 2024 |
| Will it stick? A year-long field experiment tests the effects of coral-rubble stabilisation on sessile benthic organisms | Australian Marine Sciences Association (AMSA) Conference, Hobart, Australia | 2024 |
| A synthesis of rubble bed dynamics to inform intervention site selection | Reef Resilience Symposium, Cairns, Australia | 2024 |
| Next-gen bioadhesives: helping shape the future of sustainable rubble stabilisation and reef restoration | Reef Resilience Symposium, Cairns, Australia | 2024 |
| What is rubble anyways? Opportunities and limitations to studying reef rubble substrates via remote sensing | Reef Resilience Symposium, Cairns, Australia | 2024 |
| Comparative analysis of basal attachment of 2 species of reef building coral | Volume Imaging Australia Conference, Online | 2024 |
Supported by the Queensland State Government Small Business Innovation Research Program.
