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dc.contributor.authorIrons, John Gillam, Iii
dc.date.accessioned2018-08-08T02:11:40Z
dc.date.available2018-08-08T02:11:40Z
dc.date.issued1993
dc.identifier.urihttp://hdl.handle.net/11122/9379
dc.descriptionThesis (Ph.D.) University of Alaska Fairbanks, 1993
dc.description.abstractAutumnal leaf litter that falls into streams of forested regions forms a major source of energy for stream food webs. The processing of this litter has been studied for many years, and two generalizations have come from this research: (1) nitrogen concentration is positively correlated with breakdown rate, and (2) temperature is negatively correlated with breakdown rate. Along with investigators in Michigan and Costa Rica, I examined these generalizations by estimating breakdown rates of litter of ten tree species with widely varying nutritional quality along the latitudinal gradient of Costa Rica to Michigan to Alaska. At each site, litter processing experiments were done using leaves of the same ten tree species and the same methods in streams with similar character. We found that (1) condensed tannin, a plant defense against herbivory, was more highly correlated (negatively) with breakdown rates than was nitrogen (positively correlated with breakdown), and (2) breakdown rate showed a complex response to water temperature (i.e., latitude). I propose a model of leaf litter breakdown in which the microbial contribution to litter breakdown is negatively correlated with latitude (i.e., temperature) and the invertebrate contribution to litter breakdown is positively correlated with latitude. In addition, I suggest that secondary compounds of low solubility, especially condensed tannin, should be considered along with nitrogen when evaluating a tree species for leaf litter quality.
dc.subjectEcology
dc.subjectLimnology
dc.titleLatitudinal gradients in leaf litter decomposition in streams: Effects of leaf chemistry and temperature
dc.typeThesis
dc.type.degreephd
dc.identifier.departmentDepartment of Biology and Wildlife
refterms.dateFOA2020-03-06T01:15:52Z


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