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AShowalter dissertation REVISED.pdf (2.28 MB)

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The Impact of Environmental Conditions, Food Resources, and Ecological Stoichiometry in Structured Populations

Showalter, Ann Marie
http://orcid.org/0000-0002-4581-8282
http://rave.ohiolink.edu/etdc/view?acc_num=miami1452104389

Abstract Details

2016, Doctor of Philosophy, Miami University, Ecology, Evolution and Environmental Biology.
In this dissertation, I explore how population structure and the characteristics of individuals within structured populations respond to changes in environmental conditions that affect the quantity and quality of food resources. Chapter 1: For bluegill sunfish, individual size and population size-structure is affected by factors that alter prey availability, including primary productivity, sediment-feeding gizzard shad, and intraspecific competition. In a ten-month study, I manipulated productivity and gizzard shad in experimental ponds with bluegill populations that varied in density, and I used AIC model comparisons to identify the factors most associated with bluegill response variables. Density-dependence, probably driven by resource competition, was the most consistent factor associated with individual bluegill biomass. None of the models I examined were significant in explaining adult/juvenile density or the proportion of adults. Chapter 2: I investigated how elemental imbalance between an individual’s diet and its needs varies with ontogenetic diet shifts. I examined ontogenetic changes in stoichiometry in the bluegill sunfish, which undergoes an ontogenetic diet shift from zooplankton to benthic invertebrates, and I compared imbalance between diet elemental content and organism needs before and after diet shifts. Elemental imbalance estimates indicated potential carbon limitation in all size-classes of bluegill, and the diet shift tended to reduce C imbalance relative to P. My results provide stoichiometrically-explicit support for previous findings that energetics is an important driver of bluegill diet shifts. As a consequence of the need to satisfy carbon requirements, N:P imbalance is exacerbated. Thus, ontogenetic diet shifts can produce trade-offs in elemental imbalance between elemental ratios. Chapter 3: I examined how light and nutrient conditions experienced in larval stages of the damselfly Enallagma aspersum affected development time, mass at emergence, and adult body composition. I reared larval damselflies to adulthood in outdoor mesocosms under high and low light and nutrient conditions. Light level consistently affected damselflies by altering temperature and producing temporal changes in food availability. Damselflies reared in high light had faster development times, but did not differ in mass at emergence. In addition, temperature can explain most patterns adult elemental content, although male and female C:P differed in response to light. Overall, differences in light-driven temperature effects appear to be a major factor affecting damselfly life history traits and stoichiometry.
Maria Gonzalez (Advisor)
Michelle Boone (Committee Member)
Ann Rypstra (Committee Member)
Michael Vanni (Committee Member)
Jing Zhang (Committee Member)
140 p.
Aquatic Sciences; Biology; Ecology; Freshwater Ecology; Limnology; Organismal Biology
ecological stoichiometry; bluegill sunfish; population structure; damselfly; food quality; ontogeny; gizzard shad; nutrients; elemental imbalance; nitrogen; phosphorus

Recommended Citations

Citations

  • Showalter, A. M. (2016). The Impact of Environmental Conditions, Food Resources, and Ecological Stoichiometry in Structured Populations [Doctoral dissertation, Miami University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=miami1452104389

    APA Style (7th edition)

  • Showalter, Ann. The Impact of Environmental Conditions, Food Resources, and Ecological Stoichiometry in Structured Populations. 2016. Miami University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=miami1452104389.

    MLA Style (8th edition)

  • Showalter, Ann. "The Impact of Environmental Conditions, Food Resources, and Ecological Stoichiometry in Structured Populations." Doctoral dissertation, Miami University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1452104389

    Chicago Manual of Style (17th edition)

miami1452104389
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© 2016, all rights reserved.
This open access ETD is published by Miami University and OhioLINK.