Abstract

Coral reef fish communities are essential for ecosystem health but are threatened by many of the same environmental stressors as coral. Marine heatwaves and hurricanes are intensifying with climate change and can adversely affect reef fish via physiological stress or coral loss. Additionally, Caribbean reef fish are threatened by invasive Indo-Pacific lionfish predation. Here, I determine the impacts of invasive lionfish, marine heatwaves, and hurricane passage on patch reef fish communities from 2009-2024 in The Bahamas. Using a metacommunity framework, I also analyze shifts in fish community composition spatially via network analysis to determine whether reef connectivity reduces fish species turnover through time and following hurricanes. Lionfish biomass was positively related to native fish biomass and species richness, possibly driven by attraction of lionfish to reefs with abundant prey. Although marine heatwaves negatively affected fish biomass, they had a consistent, positive effect on species richness, suggesting a complex, possibly non-linear relationship of temperature to diversity. Hurricane passage negatively affected fish biomass but had no clear impacts on species richness or turnover. Over the timeseries, beta diversity significantly increased in the metacommunity with more central, connected reefs experiencing lower species turnover, likely driven by dispersal. My findings show predictable changes in reef fish biomass to multiple stressors but demonstrate more complex responses of species richness, supporting the use of multiple metrics to more fully understand drivers of environmental change. Further, by using a metacommunity framework, my findings reinforce the prominent paradigm of a dynamic nature of reef fish assemblages over time.