Daphnia vertical position and implications for the impact of the invasive zooplankton predator, Bythotrephes longimanus, on plankton communities in south-central Ontario
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Authors
Hasnain, Sarah
Date
Type
thesis
Language
eng
Keyword
Bythotrephes longimanus , Daphnia , Daphnia mendotae , Zooplankton , Invasive Species , Introduced Predator , Daytime Vertical Position , Vertical Distribution , Intraspecific Trait Variation , Dispersal , Trophic Cascade , Food Web , Freshwater ecosystems , Limnology , Predator Density , Anti-predator response , Phytoplankton , Algae
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Abstract
Species diversity and identity play an important role in determining community structure and regulating ecosystem processes. However, species interactions are often characterized by the mean effect or response, often ignoring intraspecific variation in trait expression. In this thesis, I examined the ecological consequences of intraspecific trait variation in Daphnia vertical position in plankton communities invaded by the presence of the invasive zooplankton predator, Spiny water flea (Bythotrephes longimanus). In the first chapter, I assessed the factors influencing Daphnia vertical position response to Bythotrephes presence using a field survey of invaded and uninvaded lakes across a gradient of abiotic variables in south-central Ontario. In the second chapter, I examined the influence of Daphnia vertical position on Bythotrephes impacts on plankton communities using mesocosm experiments where I manipulated Bythotrephes presence and Daphnia vertical position. In the final chapter, I used mesocosm experiments to determine if differences in the vertical position of dispersing Daphnia influenced recovery in Daphnia populations invaded by Bythotrephes. Results from my field survey show that Daphnia vertical position response to Bythotrephes is species specific, with only D. mendotae and D. longiremis vertical position influenced by Bythotrephes presence. In invaded lakes, D. mendotae vertical position in dependent on water clarity and Bythotrephes density. Results from my mesocosms experiment suggest that Daphnia vertical position influences the type and magnitude of Bythotrephes impacts on Daphnia populations, resulting in indirect impacts on small cladocerans, large cladocerans and copepodids. Furthermore, differences in Daphnia vertical position in invaded mesocosms influenced algal densities, resulting in trophic cascades in mesocosms where more Daphnia were hypolimnetic. There was no effect of differences in vertical position of dispersing Daphnia on Daphnia populations invaded by Bythotrephes. Taken together, these results suggest that Daphnia vertical position response to Bythotrephes is species specific and that differences in Daphnia vertical position result in differences in Bythotrephes impacts on plankton communities in invaded lakes.
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Attribution 3.0 United States
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.
Queen's University's Thesis/Dissertation Non-Exclusive License for Deposit to QSpace and Library and Archives Canada
ProQuest PhD and Master's Theses International Dissemination Agreement
Intellectual Property Guidelines at Queen's University
Copying and Preserving Your Thesis
This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner.