Fish assemblages of Caribbean coral reefs: Effects of overfishing on coral communities under climate change Public Deposited

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  • March 19, 2019
  • Valdivia-Acosta, Abel
    • Affiliation: College of Arts and Sciences, Department of Biology
  • Coral reefs are threatened worldwide due to local stressors such as overfishing, pollution, and diseases outbreaks, as well as global impacts such as ocean warming. The persistence of this ecosystem will depend, in part, on addressing local impacts since humanity is failing to control climate change. However, we need a better understanding of how protection from local stressors decreases the susceptibility of reef corals to the effects of climate change across large-spatial scales. My dissertation research evaluates the effects of overfishing on coral reefs under local and global impacts to determine changes in ecological processes across geographical scales. First, as large predatory reef fishes have drastically declined due to fishing, I reconstructed natural baselines of predatory reef fish biomass in the absence of human activities accounting for environmental variability across Caribbean reefs. I found that baselines were variable and site specific; but that contemporary predatory fish biomass was 80-95% lower than the potential carrying capacity of most reef areas, even within marine reserves. Second, I examined the effect of current native predatory reef fishes on controlling the invasion of Pacific lionfish across the Caribbean. Native predators and lionfish abundance were not related, even when predatory capacity was relatively high within certain marine reserves. Third, as herbivorous fishes may facilitate coral recovery after warming events by controlling competitive macroalgae, I evaluated whether major benthic groups, such as hard corals, crustose coralline algae, and macroalgae, were associated with these fish assemblages across Caribbean and Pacific reefs. Although, macroalgae abundance was negatively related to herbivorous fishes across geographical regions, contemporary coral cover showed no association with herbivores abundance after a recent history of thermal stress. Finally, I analyzed the relationship between ~30 years of thermal stress anomalies and coral assemblages in the Caribbean and suggest that recent warming has partially promoted a shift in coral-community composition across the region that compromise reef functionality. My dissertation research highlights the complex interactions among functional groups in coral reefs, local stressors, and environmental variability across geographical scales, and provides novel insights to reevaluate conservation strategies for this ecosystem in a rapidly changing world.
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  • In Copyright
  • Peterson, Charles
  • Layman, Craig
  • Baum, Julia
  • Hurlbert, Allen
  • Bruno, John
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2014
Place of publication
  • Chapel Hill, NC
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