Ecological consequences of genetically-based thermal traits in fishes
Date
2019-05-13
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Abstract
Unprecedented contemporary rates of environmental change risk irreversible loss of biodiversity and ecosystem functioning in aquatic systems, with population persistence dependent on resiliency in thermal physiology and thermoregulation. The association between thermal physiology and behavioural traits can predict population persistence, range shifts, and evolution in the face of contemporary climate change, but the mechanisms underlying these relationships are unknown. In this thesis, I characterize the impact of abiotic environmental factors on population distributions, assess the relationship between thermal tolerance and preference traits, characterize the genetic architecture of these thermal traits, and use these empirical data to construct a mechanistic species distribution model for a genetically similar cluster in a marine environment. I found that temperature and water volume are significant drivers of age- and size-class distributions within a wild marine population of Oligocottus maculosus. I also found that population and generation significantly impacted various thermal tolerance traits, and that there were significant correlations between physiological and behavioural thermal traits in Gasterosteus aculeatus across generations and populations. I also show that the thermal tolerance limits of freshwater populations of G. aculeatus are closer to observed thermal extremes in their natural environments than their marine counterparts. Using phenotypically-divergent populations of G. aculeatus, I identified four significant quantitative trait loci (QTL) that were associated with thermal tolerance traits and that many of these traits co-localized to the same two QTL. Using these genetically-based thermal traits, I predicted a conservative but northward shift in the geographic range of the marine populations of G. aculeatus. Collectively, these data demonstrate that the inclusion of both physiological and behavioural data will be important in forming more robust predictions regarding species’ responses to climate change, with an emphasis on temperature-associated behaviours when considering predictions regarding population persistence. By integrating multiple responses to climate change and facilitating collaboration across fields, we can begin to produce more accurate and robust predictions concerning the fate of populations, communities, and ecosystems under contemporary climate change.
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Keywords
Thermal tolerance, Thermal preference, QTL mapping, Species distribution models, Climate change
Citation
Smith Wuitchik, S. J. (2019). Ecological consequences of genetically-based thermal traits in fishes (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.