Defining rarity and determining the mechanisms of rarity for North American freshwater fishes

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dc.contributor.authorPritt, Jeremy Josephen
dc.contributor.committeechairFrimpong, Emmanuel A.en
dc.contributor.committeememberAngermeier, Paul L.en
dc.contributor.committeememberDolloff, C. Andrewen
dc.contributor.departmentFisheries and Wildlife Sciencesen
dc.date.accessioned2014-03-14T20:33:24Zen
dc.date.adate2010-04-29en
dc.date.available2014-03-14T20:33:24Zen
dc.date.issued2010-01-06en
dc.date.rdate2010-04-29en
dc.date.sdate2010-04-12en
dc.description.abstractConserving rare species and protecting biodiversity depends on sound information on the nature of rarity. Rarity is multidimensional, presenting the need for a quantitative classification scheme by which to label species as rare or common. I defined rarity for freshwater fishes based on the range extents, habitat breadths, and site abundance and examined the relationship between these dimensions of rarity and imperilment. Imperiled fishes were most often rare by all three dimensions, whereas undesignated species were most often common by all three dimensions. Next, I examined the effect of sampling intensity on observed rarity of stream fish using different numerical and proportional rarity criteria and found that increasing sampling intensity increased the number of species labelled as rare with proportional criteria but did not affect the number of species labelled as rare with numerical criteria. Additional electrofishing passes within a fixed reach increases the likelihood of detecting rare and endemic species. A tradeoff between information collected and sampling resources should be carefully considered in the context of objectives when sampling for rare species. Finally, I examined the effect of regional and watershed habitat variables, biotic interaction variables, and instream habitat variables, on the rare or common status on 23 North American freshwater fishes. I also compared biological and reproductive traits among species classified into the rarity framework. Rarity was successfully explained in 19 of the 23 species and I found that regional and watershed habitat variables were the most important predictors of rarity. I also found that species large body size, high fecundity, and long age at maturity were generally more common by range extent and site abundance while those species that did not guard nests were more frequently rare by site abundance. These results indicate that large-scale variables can be used to successfully predict species rarity and rare fishes differ in their biology and reproduction from common fishes.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-04122010-150013en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-04122010-150013/en
dc.identifier.urihttp://hdl.handle.net/10919/31696en
dc.publisherVirginia Techen
dc.relation.haspartPritt_JJ_T_2010.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectsampling intensityen
dc.subjectrare speciesen
dc.subjectimperiled species listen
dc.subjectproportional rarityen
dc.subjectnumerical rarityen
dc.subjectspecies traitsen
dc.subjecthabitat templatesen
dc.titleDefining rarity and determining the mechanisms of rarity for North American freshwater fishesen
dc.typeThesisen
thesis.degree.disciplineFisheries and Wildlife Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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