Our study investigated the vulnerability of marine ecosystems to loss of functional diversity, and biogeographical drivers of community ecological functions in the Galápagos archipelago. We collected relative abundance data for 121 reef fish species sampled using Baited Remote Underwater Stereo-Video systems (stereo-BRUVs), identified 82 functional entities and described functional diversity and vulnerability based on five functional traits. We also assessed the influence of spatial and environmental variability and human management on functional entity composition and richness.
We found that Galápagos reef fish communities have a high vulnerability to functional diversity loss following species loss due to the low redundancy and high sensitivity of reef fish functional entities. Most functional entities with resilience because of functional redundancy include piscivorous diets, while most that are sensitive and represented by only one species are lower trophic levels. Variables relating to latitudinal environmental variation and marine habitat were important predictors of reef fish functional entity distribution. Our study raises concerns about the long-term functioning of Galápagos marine communities under present climate change and human management scenarios. We suggest using functional trait analysis and grouping species by ecological functions for consideration in the future marine management of Galápagos marine communities.