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The ecological consequences of the reduction of species diversity : experimental approaches

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dc.contributor.advisor Menge, Bruce A.
dc.contributor.advisor Lubchenco, Jane
dc.creator Allison, Gary William
dc.date.accessioned 2012-10-04T16:37:36Z
dc.date.available 2012-10-04T16:37:36Z
dc.date.copyright 1997-01-16
dc.date.issued 1997-01-16
dc.identifier.uri http://hdl.handle.net/1957/34118
dc.description Graduation date: 1997 en_US
dc.description.abstract The influence of loss of diversity on community dynamics and ecosystem functioning has recently received considerable attention. Although study of biodiversity has a long history within ecology, empirical investigations exploring consequences of loss have been rare. Because many factors confound diversity comparisons, experimental manipulations of diversity offer the most direct way of attributing cause to diversity loss. The effects of reduction in number of species will depend on the strength and sign of species interactions affected by loss of diversity. An experiment performed on a high zone, rocky intertidal community in which macroalgal diversity was manipulated demonstrated that effects of diversity loss will be highly dependent on which species are removed. However, effects of diversity reductions were strongest at the harsh end of a stress gradient where interactions were more positive. Thus, factors that affect the strength and sign of species interactions such as the degree of physical stress may serve as a rough guide to where the effects of diversity loss will be most severe. An assessment of the influence of diversity on community response to a strong physical perturbation was performed using an experimentally-induced thermal stress. Higher diversity treatments were most strongly affected directly by the stress because such treatments had higher abundance and therefore more biomass to lose. However, those same treatments recovered more quickly from the stress. Community recovery of initially low diversity treatments was slowed by persistence of non-typical states or slow recovery of dominant species. A simulation study was performed to assess the ability of different experimental designs to detect biodiversity effects. Our ability to predict consequences of changes in diversity will be dependent on our ability to distinguish the most influential biodiversity "components" within a system. This study uncovered a phenomenon that will be common in biodiversity studies: misidentification of one biodiversity component (e. g., an effect of a keystone species) as a different component (e. g., an effect of the number of species). I call this phenomenon "aliasing." Because of the complexity of biodiversity, experiments and observational studies will be highly susceptible to aliasing and, thus, results will require careful interpretation. en_US
dc.language.iso en_US en_US
dc.subject.lcsh Intertidal ecology -- Oregon en_US
dc.subject.lcsh Biological ecology -- Oregon en_US
dc.title The ecological consequences of the reduction of species diversity : experimental approaches en_US
dc.type Thesis/Dissertation en_US
dc.degree.name Doctor of Philosophy (Ph. D.) in Zoology en_US
dc.degree.level Doctoral en_US
dc.degree.discipline Science en_US
dc.degree.grantor Oregon State University en_US
dc.contributor.committeemember Hixon, Mark
dc.contributor.committeemember McCune, Bruce
dc.description.digitization File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6770A in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR. en_US
dc.description.peerreview no en_us


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