Multi-scale effects of environmental stress on reef fish communities

Lamb, Robert Wellington

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Year:: 2019
Contributor:: Lamb, Robert Wellington (creator); Witman, Jon (Advisor); Sax, Dov (Reader); Dunn, Casey (Reader); Kellner, James (Reader); Brown University. Biology and Medicine: Ecological and Evolutionary Biology (sponsor)
Genre:: theses
Subject:: Fishes; Coral reefs; ecology; climate change; Biotic communities; Marine ecology; Ocean; Galapagos Islands; Pacific Ocean--El Niño Current
Extent:: 22, 181 p.
DOI: https://doi.org/10.26300/z4vm-1856

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Abstract:: Environmental variation limits the distributions of species across space and affects the outcome of biotic interactions and population dynamics over time. It is unclear which species characteristics will favor resistance, resilience, or decline in response to the extremes of temperature, precipitation, and mechanical stress by wind and waves associated with global climate change. I explored the wide oceanographic variation and relatively pristine fish communities of the Galapagos Islands as a model system to study the ecological outcomes of variation in environmental stress. In response to a local, high-frequency stressor (wave exposure), I found that speed of locomotion dictates the ability of herbivores to navigate high wave exposure. Fast-moving herbivorous fishes consumed palatable macroalgae across wave exposure, whereas slower-moving urchins had limited effects when the frequency of high wave-induced flow speeds increased. This led to the derivation of a stress-mobility hypothesis, wherein mobility relative to the return time of environmental stress is the factor that best predicts an herbivore’s ability to continue feeding and exerting top-down control on benthic communities. I also compared the predictive capacity of factors related to the biogeography and ecology of 78 reef fish species to inform population trajectories over 6 years in response to a regional, low-frequency stressor (El Niño events). Planktivores were most susceptible to population declines during the cold, oligotrophic waters brought by El Niño, but showed remarkable resilience by recovering via massive larval recruitment during the subsequent La Niña period dominated by high upwelling of cold, nutrient-rich water one year later. At the height of the 2015-16 El Niño event, the strongest in recent history, I also discovered a novel ulcerative skin disease affecting 18 different species of reef fish. Associated with a bacterium Rahnella sp., the disease was temperature and density-dependent, and disappeared as El Niño subsided. By studying the effects of environmental variation on reef fish communities, my thesis aims to provide a trait-based framework for predicting the trajectory of ecological communities under climate change.
Notes:: Thesis (Ph. D.)--Brown University, 2019

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Rights: In Copyright
Restrictions on Use: Collection is open for research.

Citation

Lamb, Robert Wellington, "Multi-scale effects of environmental stress on reef fish communities" (2019). Ecological and Evolutionary Biology Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.26300/z4vm-1856

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Ecological and Evolutionary Biology Theses and Dissertations

Theses and Dissertations for the Ecological and Evolutionary Biology department.
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