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dc.contributor.advisorKeitt, Timothy H.
dc.creatorLasky, Jesse Roberten
dc.date.accessioned2013-11-14T21:32:16Zen
dc.date.issued2012-05en
dc.date.submittedMay 2012en
dc.identifier.urihttp://hdl.handle.net/2152/22194en
dc.descriptiontexten
dc.description.abstractSpatial variation in tree community composition and assembly is due in large part to dispersal limitation, spatial variation in environmental conditions, and interactions among competing trees. The relative importance of these processes may be governed by landscape structure and environmental conditions. (I) The movement of frugivores between remnant forests and successional areas is vital for tropical forest tree species to colonize successional habitats. I found that avian frugivores crossing forest edges were generally insensitive to percent cover and clustering of pasture trees. If pastures were abandoned the distance from forest edges would not likely limit frugivore visitation and seed deposition under pasture trees in my study. (II) Relatively little is known from a theoretical conservation perspective about how reserve size affects communities assembled by abiotic and dispersal limitations. Simulated small reserve systems increased the distance between environments dominated by different species, diminishing the importance of source-sink dynamics. I found a trade-off between preserving different aspects of natural communities, with greater [alpha]-diversity in large reserves and greater [gamma]-diversity across small reserve systems. (III) Functional trait diversity of co-occurring organisms may be indicative of the processes that structure communities. Across spatial scales, an axis of leaf succulence exhibited the strongest evidence for niche-based assembly among co-occurring Ficus individuals, whereas specific leaf area (SLA) showed the strongest evidence for niche-based assembly among species. Trait analyses of co-occurring individuals had greater power than analyses at the species level, especially for traits with high intraspecific variation. Environmental filtering may be stronger at higher elevations due to drought stress. (IV) Individual fitness is a function of the interaction between traits and environment, or environmental selection. I estimated spatial selective gradients affecting a subtropical tree community and found that the trait axes with the strongest selection were also those with the least spatial variation. Interestingly, factors associated with selection were quite different for growth versus survivorship. The trait-by-environment interactions I identified are strong candidates for spatial niche differentiation, and may explain how tree species coexist in this diverse subtropical forest.en
dc.format.mimetypeapplication/pdfen
dc.language.isoen_USen
dc.subjectAmazoniaen
dc.subjectFrugivoreen
dc.subjectSeed dispersalen
dc.subjectHierarchical bayesen
dc.subjectLandscape ecologyen
dc.subjectReserve sizeen
dc.subjectConservation biologyen
dc.subjectSubtropical foresten
dc.subjectTropical foresten
dc.subjectMetacommunityen
dc.titleSpatial variation in tree community assemblyen
dc.date.updated2013-11-14T21:32:16Zen
dc.description.departmentEcology, Evolution and Behavioren
thesis.degree.departmentEcology, Evolution and Behavioren
thesis.degree.disciplineEcology, Evolution and Behavioren
thesis.degree.grantorThe University of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen
dc.embargo.terms5/1/2013en
dc.embargo.lift5/1/2013en


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