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INTERACTIONS AMONG TOP-DOWN REGULATORS IN A TEMPERATE FOREST FLOOR ECOSYSTEM: EFFECTS ON MACROFAUNA, MESOFAUNA, MICROBES AND LITTER DECAY

Hickerson, Cari-Ann Marie
http://rave.ohiolink.edu/etdc/view?acc_num=csu1276104836

Abstract Details

2010, Doctor of Philosophy in Regulatory Biology, Cleveland State University, College of Science.
High species diversity and complexity of forest-floor food webs present a challenge for understanding the role of species interactions (e.g. competition and predation) as regulatory mechanisms for ecosystem processes such as decomposition and nutrient cycling. In particular, we understand very little about the roles of forest-floor predators in regulating diversity and abundance of lower trophic levels and ecosystem processes. However, ecological theory and several studies suggest that interactions among intraguild predators (IGP) may be important controls of diversity and abundance of organisms and detritus in lower trophic levels within food webs. A key prediction is that interactions among predators weaken trophic cascades. My research examined this prediction by characterizing interactions among predators and examining their effects on lower trophic levels within the forest-floor food web of Northeast Ohio. The results of the laboratory microcosm studies, in combination with several previous studies, suggest that the effects of removal treatment on intraguild predators, especially centipedes, spiders, carabid beetles, and salamander, were not the result of intraguild predation, but were more likely to have been the result of non-consumptive competitive interactions (NCEs). Predator removal from open, unrestricted field plots resulted in changes in the abundances of several groups of predators and macrodetritivores. Additionally, I found that predator manipulation affected composition of microflora within the soils at my field site. The mechanisms for this effect remain uncertain but may be indicative of antibiotic interactions within the soil through bacteria dispersed through skin secretions and feces of predators, particularly salamanders. This work contributes significantly to a growing body of evidence indicating that territorial predators, such as P. cinereus, which are constrained to spatially fixed microhabitats, can be strong regulators of guild members and lower trophic levels. My results also support an important role for top-down, predator-mediated regulation of species composition in a forest-floor, detrital food web, a system that is commonly thought to be regulated primarily through bottom-up effects of organic matter supply, i.e, leaf litter. Further, this is the only study of which I am aware that attempted, and detected, significant top-down, predator-mediated effects at multiple trophic levels, including the microbial level, in the complex food web of the temperate forest-floor.
B. Michael Walton (Advisor)
Julie Wolin (Committee Member)
Jeff Johansen (Committee Member)
Joe Keiper (Committee Member)
Ron Midura (Committee Member)
Rebecca Drenovsky (Other)
Paul Doerder (Other)
162 p.
Ecology
food webs; temperate forest floor; intraguild predators; trophic cascade; competition; Plethodon cinereus; centipedes

Recommended Citations

Citations

  • Hickerson, C.-A. M. (2010). INTERACTIONS AMONG TOP-DOWN REGULATORS IN A TEMPERATE FOREST FLOOR ECOSYSTEM: EFFECTS ON MACROFAUNA, MESOFAUNA, MICROBES AND LITTER DECAY [Doctoral dissertation, Cleveland State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=csu1276104836

    APA Style (7th edition)

  • Hickerson, Cari-Ann. INTERACTIONS AMONG TOP-DOWN REGULATORS IN A TEMPERATE FOREST FLOOR ECOSYSTEM: EFFECTS ON MACROFAUNA, MESOFAUNA, MICROBES AND LITTER DECAY. 2010. Cleveland State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=csu1276104836.

    MLA Style (8th edition)

  • Hickerson, Cari-Ann. "INTERACTIONS AMONG TOP-DOWN REGULATORS IN A TEMPERATE FOREST FLOOR ECOSYSTEM: EFFECTS ON MACROFAUNA, MESOFAUNA, MICROBES AND LITTER DECAY." Doctoral dissertation, Cleveland State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=csu1276104836

    Chicago Manual of Style (17th edition)

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© 2010, all rights reserved.
This open access ETD is published by Cleveland State University and OhioLINK.