Understanding anthropogenic disturbance on coral reefs through species traits

As climate change and local stressors reshape species assemblages, our understanding of ecosystems and how to manage them increasingly centres on their changing function. From the perspective of species traits, knowledge gaps remain around disturbance responses and particularly relationships between different taxa. This thesis explores disturbances on coral reefs through a trait-based lens, and highlights avenues through which these perspectives can inform future management strategies. First, this work investigates how trait-derived groups of fishery target species respond differentially to fishing pressure, discovering that groups sharing similar traits also share responses to fisheries activity. Positing that by extension trait groups also respond similarly to management actions, it proposes a framework for incorporating trait information into conservation decision-making. Next, an analysis of linked trait space distributions between corals and fish finds that they become decoupled following a coral bleaching disturbance, driven by changes in the trait composition of the coral community whilst the fish remained relatively stable. A follow-up study highlights how subsets of the fish assemblage make unique contributions to linked trait space distributions and assesses their importance for detecting habitat structuring across the coral and fish community. Finally, this thesis evaluates long-term changes in the functional composition and cross-taxa relationships between coral and fish assemblages over successive, varied disturbances. It finds fluctuations in the functional diversity of coral and fish communities explained by latitude, shelf position and disturbance history, which are also reflected in changes in shared structuring between coral and fish trait assemblages. The most influential traits in temporal cross-taxa associations indicate that functions such as structural complexity and herbivory are crucial for relationships between coral and fish assemblages. As a whole, this thesis examines how anthropogenic disturbance affects the trait composition of coral reef communities, identifying aspects of resistance and vulnerability that can inform future management approaches.