Monitoring the impacts of ecosystem-based coral reef restoration on nocturnal reef ecology

Abstract

Coral reefs are iconic centres of biodiversity but are severely threatened by climate change and chronic and acute anthropogenic disturbance. In response, coral reef restoration is expanding in scale and innovation to aid reef recovery. Ecosystem-based restoration is an emerging technique that restores functional interactions to aid coral recovery and resilience. This is a promising tool but requires monitoring that captures the diverse range of ecological interactions that are being restored. Nocturnal activity on restoration reefs has not been studied, yet it is a period of heightened activity for functionally important groups. In this thesis, I experimentally investigate the influence of ecosystem-based restoration techniques—acoustic enrichment and fish stocking—on the nocturnal ecology of restoration reefs. In Chapter 2, using infrared video footage, I found that both ecosystem-based restoration treatments had significantly different community compositions to the control, where predatory fish drove the differences in the acoustic enrichment reefs, but not at the fish-stocked or control reefs. This highlights important directions for future research to understand the impact that nocturnal visitors have on restoration outcomes. In Chapter 3, using automated eco-acoustic indices and manually identified fish sound metrics, I found no clear difference between restoration treatments in the soundscape. There was tentative evidence that fish-stocked reefs had an enhanced soundscape, with a greater amplitude index score when compared to control reefs. I discuss the potential complementarity between the findings of Chapter 2 and 3 and emphasise the need to use acoustic monitoring alongside other biodiversity monitoring. Overall, my thesis highlights the importance of varied monitoring techniques that shed light on the potential opportunities and obstacles that restoring ecological interactions may bring for coral reef restoration. This knowledge is crucial to ensuring that restoration is as effective as possible, to safeguard the future of coral reefs in this rapidly changing world.

Date of Award	1 Oct 2024
Original language	English
Awarding Institution	University of Bristol
Supervisor	Steve Simpson (Supervisor) & Andrew N Radford (Supervisor)