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Spatial Correlation and Facilitation Between Dreissena and Hexagenia: Possible Food-Web Disruption?

DeVanna, Kristen M.
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1320935549

Abstract Details

2011, Doctor of Philosophy, University of Toledo, Biology (Ecology).
Understanding what factors drive an organism’s population fluctuations in time and space can be very difficult in complex ecosystems due to changing environmental conditions and issues with spatial scale. In this dissertation, I examined the effect of soft-sediment Dreissena (D. polymorpha and D. rostriformis bugensis) clusters, an invasive ecosystem engineer, on a native burrowing mayfly (Hexagenia limbata and H. rigida). Specifically, at the small-scale, I examined the effect of Dreissena clusters on Hexagenia: 1) habitat preference, 2) availability as prey, and 3) behavior during changing abiotic (low oxygen) and biotic (presence of a predator) conditions. At the large scale I examined: 1) the spatial association of Hexagenia and Dreissena and 2) the abiotic and biotic factors influencing Hexagenia spatial distribution and temporal fluctuations. I conducted experiments, spatial mapping and statistics, and generalized additive models to examine these objectives. Hexagenia were found to prefer sediment covered with both live and artificial clusters over bare sediment, likely due to decreased fish predation when under Dreissena clusters in turbid conditions. Hexagenia also received benefit from Dreissena clusters during hypoxic conditions; Hexagenia were able to exit anoxic burrows to seek well-oxygenated waters while staying within the Dreissena cluster as refuge from predation. At the large scale, Hexagenia density was not related to Dreissena density, however Hexagenia were more likely to occur where Dreissena were also present. Similarly, Dreissena density was not a good predictor of Hexagenia density in western Lake Erie, but abiotic factors, such as percent silt, organic carbon, depth, and distance from western shore did significantly influence Hexagenia distribution. Sites with high average Hexagenia density were clustered near the western shoreline of Lake Erie and exhibited a two-year density cycle, likely a density-dependent regulation. Overall, abiotic factors appear to be the diving force behind Hexagenia spatial distribution, temporal fluctuations a result of a density-dependent population regulation, and biotic factors likely regulate small-scale habitat preference and behavior of Hexagenia. What is important is that Dreissena presence and resulting habitat alterations are not inhibiting Hexagenia presence and Hexagenia are maintaining sustainable population levels in areas with high densities of dreissenids in western Lake Erie.
Christine Mayer, PhD (Advisor)
Jonathan Bossenbroek, PhD (Committee Member)
Thomas Bridgeman, PhD (Committee Member)
Lynda Corkum, PhD (Committee Member)
Kenneth Krieger, PhD (Committee Member)
152 p.
Aquatic Sciences; Ecology; Environmental Studies; Limnology
ecosystem engineer; invasive species; hypoxia; mayflies; Dreissena; Hexagenia; zebra mussels; predation; yellow perch; round goby; quagga mussels; habitat selection

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Citations

  • DeVanna, K. M. (2011). Spatial Correlation and Facilitation Between Dreissena and Hexagenia: Possible Food-Web Disruption? [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1320935549

    APA Style (7th edition)

  • DeVanna, Kristen. Spatial Correlation and Facilitation Between Dreissena and Hexagenia: Possible Food-Web Disruption? 2011. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1320935549.

    MLA Style (8th edition)

  • DeVanna, Kristen. "Spatial Correlation and Facilitation Between Dreissena and Hexagenia: Possible Food-Web Disruption?" Doctoral dissertation, University of Toledo, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1320935549

    Chicago Manual of Style (17th edition)

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© 2011, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.