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A multi-trophic level examination of recreational impacts on a national wild and scenic river

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dc.contributor.advisor Li, Judith Lew
dc.creator Wright, Kristopher Keith
dc.date.accessioned 2012-10-08T20:49:28Z
dc.date.available 2012-10-08T20:49:28Z
dc.date.copyright 1997-02-28
dc.date.issued 1997-02-28
dc.identifier.uri http://hdl.handle.net/1957/34237
dc.description Graduation date: 1997 en_US
dc.description.abstract Initially, components of an aquatic food web were examined to study impacts of recreational use on the aquatic ecology of Quartzville Creek, Oregon in 1995 and 1996. Measurements of the food web components consisted of observations of harlequin ducks (Histrionicus histrionicus), visual counts of the larval caddisfly Dicosmoecus gilvipes, benthic macroinvertebrate samples, and chlorophyll a biomass of epiphytic algae. In February 1996, a major flood forced closure of the study area to the general public throughout the 1996 season, providing a "natural experiment" situation. The difficulty was how to distinguish between effects of flood damage and effects of the presence/absence of humans. By accounting for various measured abiotic and biotic factors using multiple regression, distinctions between disturbance effects were made with regard to abundances of D. gilvipes and benthic invertebrates. Regression analysis also was used to account for annual site differences in average depth, habitat types and substrates. Generally, recreational impacts were apparent at more localized spatial and temporal scales than were effects from extensive flooding. However, scales at which these disturbances affected components of the food web varied. Impacts of the flood included an 81% reduction in overall D. gilvipes densities, a 37% decrease in benthic abundance, reduced chlorophyll a biomass, fewer numbers of ducks and changes in site substrates and habitats. These impacts occurred across all study sites and throughout the 1996 season, except for the recovery of benthic abundance to 1995 levels by July 1996. Recreational impacts were apparent at the site scale and appeared to be seasonal in duration. In 1995, sites without human use had significantly higher densities of D. gilvipes than those sites impacted by recreation. In 1996, no significant differences in D. gilvipes densities among sites were observed after accounting for flood effects and site differences. There were no direct significant relationships to human use among sites with regard to total benthic invertebrates, chlorophyll a biomass or H. histrionicus. Despite the lack of a direct spatial relationship between H. histrionicus and D. gilvipes at the local scale of this study, there were strong temporal correlations between harlequin brood development and D. gilvipes maturation. en_US
dc.language.iso en_US en_US
dc.subject.lcsh Stream ecology -- Oregon -- Quartzville Creek en_US
dc.subject.lcsh Quartzville Creek (Or.) -- Recreational use -- Environmental aspects en_US
dc.subject.lcsh Outdoor recreation -- Environmental aspects -- Quartzville Creek en_US
dc.title A multi-trophic level examination of recreational impacts on a national wild and scenic river en_US
dc.type Thesis/Dissertation en_US
dc.degree.name Master of Science (M.S.) in Fisheries Science en_US
dc.degree.level Master's en_US
dc.degree.discipline Agricultural Sciences en_US
dc.degree.grantor Oregon State University en_US
dc.contributor.committeemember Jarvis, Robert
dc.contributor.committeemember Matzke, Gordon
dc.description.digitization File scanned at 300 ppi (Monochrome, 8-bit Grayscale) using ScandAll PRO 1.8.1 on a Fi-6670 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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