Fisheries and Wildlife Sciences electronic theses and dissertations (MU)
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The items in this collection are the theses and dissertations written by students of the Department of Fisheries and Wildlife Sciences. Some items may be viewed only by members of the University of Missouri System and/or University of Missouri-Columbia. Click on one of the browse buttons above for a complete listing of the works.
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Item An ecological study of loggerhead shrikes in central Missouri(University of Missouri--Columbia, 1982) Kridelbaugh, Alan Lee"The objectives of this study were to: 1. Document the population decline and current distribution of loggerhead shrikes in Missouri. 2. Investigate the nesting ecology of loggerhead shrikes in Missouri. 3. Determine habitat selection by loggerhead shrikes in the breeding season. 4. Investigate food habits of loggerhead shrikes in the breeding season. 5. Propose management guidelines to halt the decline of loggerhead shrikes in Missouri."--Page 5.Item Relations among zooplankton abundance, biomass, community structure, and lake trophic state in selected Midwestern waterbodies(University of Missouri--Columbia, 1988) Canfield, Timothy J.; Jones, John R."The objectives of this study were to describe abundance, biomass, and community structure of zooplankton in selected midwestern waterbodies and to evaluate several of the accepted empirical generalizations concerning the response of zooplankton communities to lake trophic state with data from midwest waterbodies. The empirical generalizations examined in this thesis are that as lakes become more productive: (1) total zooplankton abundance increases (Brooks 1969; Patalas 1972; Patalas and Saiki 1973; O ’Brien and de Noyelles 1974; Beaver and Crisman 1982) ; (2) total zooplankton biomass increases (McCauley and Kalff 1981; Mills and Schiavone 1982; Hanson and Peters 1984; Yan 1986); (3) ecological efficiency by which energy is transfered from the primary producers to the zooplankton decreases (Hillbricht-Ilkowska et al. 1972, as cited in Pederson et al. 1976; McCauley and Kalff 1981); (4) zooplankton mean length shifts toward smaller individuals (Brooks 1969; McNaught 1975); and (5) large grazing zooplankton can potentially reduce the amount of chlorophyll a per unit of total phosphorus (Edmondson and Litt 1982; Pace 1984; Shapiro and Wright 1984)."--Page 2.Item Statistical analysis of the impact of technical and economic factors of crop yield(University of Missouri--Columbia, 1981) El-Shereif, Saad; Johnson, Stanley R.The objective of the study has been to derive and apply an aggregate yield model designed to better reflect the impact of technical change. The application is to corn yield for selected crop reporting districts in Missouri. The method developed provides for the introduction of an economically and technically determined potential yield into aggregate yield functions similar to those in common use. The study was conducted in three major phases. First, statistical estimation of technical corn production function was undertaken. Corn yield was estimated as a function of nitrogen, a technology index, and a weather index. Thus, the estimated production function relates controlled and uncontrolled factors to corn yield. The second phase of the study concerned the determination of the potential corn yield using the production function estimated from the experiment station data. An expression for the profit maximizing corn yield based on economic and environmental factors was determined. The resulting expression related the optimal output or yield to output and input prices and the technology index. This profit maximizing yield was viewed as representing the potential under normal weather conditions; thus both an economic and physical concept. The third phase of the study used the potential yield in statistically estimating an aggregate corn yield relationship at the crop reporting district level. One and two production period models incorporating this proxy variable were estimated. Both models were simple specifications, highlighting the impact of the potential yield variable. Price and technology elasticities were calculated. The estimated price elasticities were found similar to those from other studies. Finally, 20 percent changes in the corn to nitrogen price ratio were assumed and elasticities were estimated to test for the response of the aggregate corn yield to economic factors. The response to the price ratio increase differed from that to the decrease. This was because of the economic feedback effect to the potential yield. In general, the results suggest that the potential yield variable can replace trending for technology and improve the economic structure of aggregate yield functions.Item Investigating potential effects of the agricultural contaminants nitrogen and copper on high-elevation lake ecosystems in Sequoia National Park, California(University of Missouri--Columbia, 2024) Ruso, Gabrielle; Paukert, Craig P.; Webb, Elisabeth B.Benthic algae blooms in remote mountain lakes are an emerging concern, but there are many questions regarding what factors influence this phenomenon. In Sequoia National Park in the Sierra Nevada mountains of California, previous research has shown that atmospheric deposition of the macronutrient nitrogen can increase algae growth. Drift modeling also indicates that this region likely receives deposition of copper, a micronutrient, from nearby agricultural pesticide use. As such, we designed a series of studies in the Tokopah Basin with the following objectives: 1) quantify concentrations of nitrogen and copper in high elevation lakes, and evaluate relationships with landscape variables and periphyton growth metrics, 2) investigate the potential for nitrogen and copper to fuel periphyton growth and modify community structure using an in-situ experiment, and 3) evaluate interactions of copper with Pacific chorus frog (Pseudacris regilla) tadpole development. We observed spatiotemporal trends in nitrogen and copper concentrations in lake media, but no detectable effect of these elements on periphyton growth. However, our in situ experimental study revealed that greater copper concentrations reduced periphyton growth and diversity, and that nitrogen and copper worked interactively to alter the algae community. Finally, we found that copper concentrations in tadpoles declined as they developed. This research provides baseline copper concentration and periphyton growth data for future studies, evidence that high nitrogen and low copper concentrations can promote the abundance of specific benthic algae taxa of concern, and evidence that developing tadpoles are unlikely to accumulate and transport copper from aquatic to terrestrial ecosystems.Item Small mammal responses to prairie reconstruction and prescribed burns(University of Missouri--Columbia, 2024) Wimms, Chantelle Marietta; Halsey, SamniquekaAs prairie reconstructions become more relevant, we must understand the impact of reconstruction and a common prairie management practice, prescribed burning, on small mammals. It is believed that small mammals may recover at different times after reconstruction or burning based on a vegetative cover threshold specific to each species. The goal of this study was to investigate whether small mammal abundance is affected by vegetation using deer mice (Peromyscus maniculatus), white-footed mice (Peromyscus leucopus), and prairie voles (Microtus ochrogaster). I first determined whether vegetation functional groups were affected by prescribed burns or reconstruction using vegetation species richness, Shannon H diversity, and percent cover. An Akaike Information Criterion (AIC) was also used to determine whether changes in vegetation cover for each functional group influence small mammal abundance. Findings suggest vegetation was affected by restoration and prescribed fires. Shannon H diversity and richness were higher for the remnant prairie and generally increased with time postfire. Reconstruction had similar effects as fire, though less pronounced. Fire and reconstruction had little effect on small mammals and no vegetational functional group was found to influence small mammal abundance. There was also evidence of potential competition between grasses and forbs. I recommend burning more frequently as the effects of prescribed fires weaken at around two years.