Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"stream ecosystem"”.
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Effects of physical and chemical disturbance on stream ecosystem structure and function
… influence the structure and function of stream ecosystems. While past investigations have focused on the response of community indicators to stream disturbances, functional indicators may also be helpful for assessing stream ecosystem health. To date, few studies have compared the …
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A study of a Cape mountain stream ecosystem and its response to fire
… of a two-year (1986-1988) study of a mountain stream draining a small catchment in the south-western Cape, South Africa. The catchment was deliberately burnt half-way through the study period. The study was undertaken because although fire is a major natural disturbance, and also a major tool …
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Effects of beaver dam analogs on stream ecosystem function of Crab Creek, Washington State
… WA. Beaver dam analogs are structures placed in streams to mimic the ecosystem effects of beaver activity and are increasingly used as a stream restoration technique. The primary goals of placing these BDAs in the stream was to impound sediment and create a new floodplain at the currently incised …
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Contamination of a soft-water stream ecosystem in southwest Virginia by highway-generated heavy metals
Study of two sections of a stream associated with highways of different traffic densities and a third section used as a reference area demonstrated that concentrations of lead, nickel, cadmium, and zinc in sediments, benthic macroinvertebrates, and fish were highly correlated to the amount of …
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Stream functional response to mountaintop removal and valley fill coal mining
… rubble is dumped into adjoining valleys and streams. Filling valleys eliminates stream headwaters and may result in loss of stream ecosystem functions, which are dependent on temporal and lateral connectivity in river networks. To determine the affect of MTRVF on stream ecosystem function, …
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Influence of Agricultural Land Use on Allochthonous Input and Leaf Breakdown in Southern Appalachian Streams
Streams and terrestrial ecosystems are linked through allochthonous organic matter inputs from streamside vegetation. This allochthonous material makes up the energy base for forested aquatic food webs. Therefore, removal of riparian vegetation associated with agricultural land use affects stream …
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Determining the Effects of Water Quality on Stream Metabolic Function of Urban Stream Corridors in Columbus, Georgia
<p>Urbanization alters streams, disrupting their natural habitat and inducing changes in nutrient dynamics and primary productivity. These human-induced interventions diminish ecological structure, homogenizing once-diverse ecosystems and posing a risk of impairment or destruction. Continuous …
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Moving beyond the stream reach: Assessing how confluences alter ecosystem function and water quality in freshwater networks
… of carbon and nutrients are shaped both by in-stream processes and the surrounding landscape. Streams receive and transport materials from upstream and terrestrial sources that support in-stream ecosystem processes and regulate downstream water quality. Understanding how these processes within …
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Comparison of Heterotrophic Activity in Forested Streams Originating from Wetland and Agricultural Tile Drainage Sources
… Ontario, Canada, have resulted in many headwater streams being sourced by agricultural tile drains instead of wetlands. Tile drainage inputs can influence stream conditions (i.e., temperature, hydrology, and water chemistry) that are important drivers of ecological function. To assess the …
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Habitat suitability modeling for Lontra canadensis in east Tennessee
… wildlife. As river otters are indicators of stream ecosystem health, maintaining habitat that is suitable to L. canadensis would also mean providing quality habitat for many riparian species.
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The Effects of Nutrient Concentrations on Macroinvertebrate Distributions in Georgia
… source pollutant in Georgia's running water ecosystems. Nutrients can naturally occur in low amounts and are typically increased in streams as a result of industry, agriculture, silviculture, and urbanization. In large amounts, nutrients can cause many problems to occur in the stream …
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A Post-Restoration Assessment of the Fishes and Macroinvertebrates of Mill Branch, Knox County, Kentucky, with Emphasis on the Blackside Dace (Chrosomus cumberlandensis)
<p>The first stream habitat restoration project for the federally threatened blackside dace, Chrosomus cumberlandensis (Starnes and Starnes), was initiated in fall 2005 on Mill Branch, a small headwater stream located in the Upper Cumberland River basin, Knox County, Kentucky. The lower 700 meters …
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Impacts of Land-Use on Leaf Breakdown and Macroinvertebrate Assemblages in Southern Appalachian Streams
… have long been associated with alterations in stream ecosystem structure and function, however, 'exurbanization' and its impact on streams is poorly understood. This study compares the ecosystem structure and function of 9 southern Appalachian streams of differing land-use (forested, exurban, …
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Litter Conditioning is Differentially Affected by Leaf Species, Phosphorus Enrichment, and Light Availability
… pervasive and detrimental threats to aquatic ecosystems worldwide. In streams that rely on allochthonous basal food resources, such as leaves, nutrient pollution can result in altered food quality and decreased carbon (C) standing stocks. However, the magnitude and mechanisms of this change in …
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Organic Matter Processes of Constructed Streams and Associated Riparian Areas in the Coalfields of Southwest Virginia
Central Appalachian headwater streams in coalfield areas are prone to mining disturbances, and compensatory mitigation is required in cases of documented impacts. Stream construction on reclaimed mines is a common mitigation strategy. Streams constructed as compensatory mitigation are meant to …
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Influence of Multiple Disturbances on Stream Structure and Function
… the influence of multiple disturbances on ecosystem structure and function in a headwater stream adjacent to an abandoned arsenic mine using an upstream (reference) and downstream (mine-influenced) comparative reach approach. In this study, floods were addressed as a pulse disturbance, and …
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Quantifying changes in macroinvertebrate community composition, biomass, and emergence in response to mining-induced salinization in central Appalachian streams
Many ecosystems are losing biodiversity, raising concern for the services they provide. However, the extent of loss is uncertain, especially for insects that use freshwater during their life. Further study is needed to assess freshwater insect abundances and diversity. In Central Appalachian …
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Assessing Organic Matter Breakdown and Associated Macroinvertebrate Community Structure in Headwater Streams: Effects of Hydrologic Gradients and Upland Timber Harvesting
… and upland timber harvesting with different streamside management zone widths on yellow-poplar (<i>Liriodendron tulipifera</i>) processing and the associated macroinvertebrate community structure in the Cumberland Plateau ecophysic region, U.S.A. Prior to upland timber harvesting, 5.0 ± 0.1 g …
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Predation effects of benthivorous fish on stream food webs – a large scale and long term field experiment
… lakes and reservoirs. Thus, the knowledge about stream ecosystems is much more rudimentary than that for lakes in this respect. The aim of this thesis, therefore, was to describe and assess the effects of fish predation in natural stream ecosystems. For that purpose a reach scale field experiment …
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Influence of riparian forest and agricultural land use on community structure and ecosystem function in headwater streams
… forest buffers are often promoted to improve stream water quality and instream habitat in agricultural areas because the vegetation can filter runoff, reduce bank erosion, and restore channel morphology. However, previous studies have found that protecting narrow strips of riparian areas, …