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dc.contributor.author Sircom, Julie
dc.date.accessioned 2009-05-22T14:21:58Z
dc.date.available 2009-05-22T14:21:58Z
dc.date.issued 2009
dc.identifier.uri http://hdl.handle.net/10222/11486
dc.description.abstract The North Mountain of the Annapolis Valley, NS, in eastern Canada, is a ~200 km basalt ridge drained by many small first or second order streams in independent catchments. The area is fairly uniform geologically, presenting an opportunity to compare streams of similar chemistry, slope and aspect, that vary in other respects, such as invertebrate community structure. In this thesis, I examine two macroinvertebrate functional groups to determine key factors influencing their abundance, composition and diversity across catchments. Chapters 2 and 3 are concerned with the predatory invertebrate guild in eight of the streams, in two groups separated by ~65 km. In Chapter 2, I assessed factors influencing composition of the predator guild using similarity matrices. Similarity in predator composition declined with distance, and streams that were more similar in disturbance (spates) were more similar in predator composition. Similarity within one family, Rhyacophilidae, was related to similarity in fish population. Chapter 3 reports the results of laboratory experiments involving two widespread species. Field data suggested an asymmetric interaction between Sweltsa onkos (Plecoptera: Chloroperlidae) and Rhyacophila vibox (Trichoptera: Rhyacophilidae); behavioural observations in artificial streams supported this. In the presence of R. vibox, S. onkos had higher mortality and injury rates, and grew less. The results of these chapters suggest that, although disturbance is important in shaping community structure, the results of interspecific interactions can be detected at large scales. S. onkos can only attain high numbers in streams where fish predation reduces the abundance of R. vibox. Chapter 4 examines biodiversity patterns in the macroinvertebrate detritivore guild in 25 streams encompassing ~80 km of the ridge. Using density and richness of the detritivore community, detrital resource quantity, and top predator abundance, I looked for evidence in support of several mechanisms that can lead to positive species-energy relationships. Patterns conformed to expectations of the ‘More Individuals Hypothesis’. It appears that taxonomic richness of the detritivore guild increases with detrital resource availability because more taxa can attain their minimum viable population size where more resources are available. en_US
dc.language.iso en en_US
dc.publisher Springer en_US
dc.subject insect en_US
dc.subject stream en_US
dc.subject community en_US
dc.subject biodiversity en_US
dc.subject competition en_US
dc.subject predation en_US
dc.date.defence 2009-03-19
dc.contributor.department Department of Biology en_US
dc.contributor.degree Doctor of Philosophy en_US
dc.contributor.external-examiner Dr. Joseph Culp en_US
dc.contributor.graduate-coordinator Dr. Paul Bentzen en_US
dc.contributor.thesis-reader Dr. Jeffery Hutchings en_US
dc.contributor.thesis-reader Dr. Ian McLaren en_US
dc.contributor.thesis-supervisor Dr. Sandra Walde en_US
dc.contributor.ethics-approval Not Applicable en_US
dc.contributor.manuscripts Yes en_US
dc.contributor.copyright-release Yes en_US

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