Investigation into the Spatial Scale Dependence of the Biodiversity Structure and Ecosystem Function of the Belize Barrier Reef System

Abstract

Understanding the spatial variability of coral reef communities is essential for predicting ecosystem function and informing conservation strategies. This study investigates the relationships between benthic composition and reef fish biomass and diversity across multiple spatial scales within the Belize Barrier Reef System (BBRS). Standardised ecological surveys were conducted across four geographically distinct regions and two major reef habitats—fore reefs and patch reefs—encompassing 1,280 transects. Analyses focused on fish species richness, biomass distribution across trophic groups, and benthic taxonomic and structural composition.
Reef fish species richness and biomass varied significantly among locations, with diversity and total biomass highest at sites characterised by greater structural complexity. Fore reefs and patch reefs supported distinct community assemblages, but spatial variation was more strongly influenced by location than by habitat type alone. Benthic assemblages also exhibited clear regional and habitat-level structuring, with patch reefs dominated by macroalgae, turf algae, and seagrasses, and fore reefs by live coral and gorgonians.
Multivariate analyses revealed strong statistical associations between benthic structure and fish biomass. Key benthic predictors included turf algae, live coral, macroalgae, seagrass, and gorgonian cover, though the strength and direction of these relationships varied among trophic groups. Sites with greater benthic compositional and structural heterogeneity consistently supported higher functional group biomass and greater ecological diversity.
These findings highlight the scale-dependent nature of reef ecosystem dynamics and underscore the ecological importance of benthic habitat composition in shaping fish community structure. The results advocate for spatially explicit, trait-informed conservation approaches that maintain benthic heterogeneity and habitat mosaics. Considering increasing anthropogenic and climatic pressures, protecting the structural and compositional diversity of reef habitats will be essential to sustaining fish biodiversity, ecological function, and the resilience of coral reef ecosystems in the BBRS.

Date of Award	18 Mar 2026
Original language	English
Awarding Institution	University of Portsmouth
Supervisor	Michelle Hale (Supervisor), Trevor John Willis (Supervisor) & Jim Smith (Supervisor)