Show simple item record

dc.contributor.authorDeVore, Jayna Lynn
dc.date.accessioned2014-03-04T20:23:52Z
dc.date.available2014-03-04T20:23:52Z
dc.date.issued2011-12
dc.identifier.otherdevore_jayna_l_201112_phd
dc.identifier.urihttp://purl.galileo.usg.edu/uga_etd/devore_jayna_l_201112_phd
dc.identifier.urihttp://hdl.handle.net/10724/27699
dc.description.abstractPlants play a major role in the construction and maintenance of ecosystems, supporting green food webs through herbivory and brown food webs through detrital inputs, affecting abiotic habitat variables, and influencing energy flow through these systems by changing the structural context in which trophic transfers take place. Alterations in these communities, such as those following plant invasion, may therefore affect consumers within impacted habitats. However, the multifaceted roles of plants makes the nature and strength of these effects difficult to predict. This dissertation explores detritally and structurally-mediated effects through which invasion by the Asian grass Microstegium vimineum influences forest floor consumers through investigating belowground C dynamics, abiotic parameters, energy flow, and the growth and survival of 3200 American toads, 800 southern leopard frogs, and 200 eastern newts across eight independent invasion fronts. The mechanisms behind observed effects were further explored through manipulations of the presence of lycosid spider predators and short-term foraging and survival trials within paired invaded and uninvaded enclosures. Belowground, this plant was found to influence abiotic habitat parameters and carbon dynamics, potentially contributing to observed effects on the production of microarthropods. However, it also serves as an important basal resource, making it likely that bottom-up influences of this plant are a consequence of changes in detrital communites in invaded habitats rather than resource sequestration of nonindigenous plant tissues. Investigation of the mechanisms through which stilt grass influences the American toad demonstrated that structural changes initiated a contextually-mediated dampening of intraguild predation rates among lycosid spiders, increasing their survival, and thereby augmenting predation pressure on metamorphic toads. Interspecific comparisons of the effects of invasion on three amphibians utilizing disparate metamorphic strategies revealed that the nature of the influence of invasion may be predicted by the metamorphic strategy of the species in question, as small, actively foraging toads are susceptible to top-down pressures while larger, sit-and-wait leopard frogs are sensitive to bottom-up effects and cryptic, toxic eastern newts did not respond to trophic effects. This research demonstrates that invasion indirectly affects consumers through alterations in detrital inputs and habitat structure, although the nature and strength of these effects varies interspecifically.
dc.languageeng
dc.publisheruga
dc.rightspublic
dc.subjectinvasive species
dc.subjectexotic plant
dc.subjectdetrital food web
dc.subjectsoil food web
dc.subjectroot exudates
dc.subjectpriming effect
dc.subjectbelowground
dc.subjectaboveground
dc.subjectarthropod
dc.subjectstructural complexity
dc.subjectcontextually-mediated indirect effects
dc.subjectbottom-up
dc.subjecttop-down
dc.subjectautogenic ecosystem engineer
dc.subjecttrophic effects
dc.subjectmetamorphic strategy
dc.subjectbehavioral syndromes
dc.subjectintraguild predation
dc.subjectforaging strategy
dc.subjectJapanese stilt grass
dc.subjectNepalese brown-top
dc.subjectMary's grass
dc.subjectMicrostegium vimineum
dc.subjectlycosid spider
dc.subjectamphibian
dc.subjectAmerican toad
dc.subjectAnaxyrus americanus
dc.subjectBufo americanus
dc.subjectSouthern leopard frog
dc.subjectLithobates sphenocephalus
dc.subjectRana sphenocephala
dc.subjecteastern newt
dc.subjectNotophthalmus viridescens
dc.titleAn exercise in complexity
dc.title.alternativeindirect influences of invasion by an exotic grass (Microstegium vimineum) on forest floor food webs
dc.typeDissertation
dc.description.degreePhD
dc.description.departmentDaniel B. Warnell School of Forestry and Natural Resources
dc.description.majorForest Resources
dc.description.advisorJohn C Maerz
dc.description.committeeJohn C Maerz
dc.description.committeeSteven B. Castleberry
dc.description.committeeJohn Carroll
dc.description.committeeMark Bradford


Files in this item

FilesSizeFormatView

There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record