Speed Presentation 2024 Australian Marine Sciences Association Annual Meeting combined with NZMSS

Will it stick? A year-long field experiment tests the effects of coral-rubble stabilisation on sessile benthic organisms (#339)

Tanya Dodgen 1 , Catherine Kim 1 , Tania Kenyon 2 , Scott Bryan 1
  1. Queensland University of Technology, Brisbane, QLD, Australia
  2. University of Queensland, Brisbane

Recent cyclones and bleaching events on Australia’s Great Barrier Reef have degraded some popular tourist sites from high coral cover to coral rubble. Rubble beds are difficult to restore using traditional outplanting techniques because outplants have low survival rates in loose substrate. In response, some tourism operators are trialling rubble stabilisation methods, including securing rubble with aluminium panels. Stabilisation is expected to increase survivorship of smaller corals and may also enhance the community of benthic organisms that naturally stabilise rubble by growing over fragments and binding them together, like ascidians and sponges. However, stabilisation may favor coral-competitors such as cyanobacteria or macroalgae. In a one year field experiment (2023-24) on Moore Reef, we deployed 1 m2 stabilising aluminium panels across a site of 110m2. We surveyed the community composition of binding organisms and the frequency of binding in control vs stabilised plots at 4, 8, and 12 months post intervention. Preliminary observations show more binding occurring in stabilised plots, mostly due to algal turf, but fewer corals were present and tended to be smaller than in control plots. Improving our understanding of how rubble stabilisation affects benthic communities is crucial to inform restoration strategies and predict reef recovery outcomes