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 100 for “"headwater streams"”.
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Logging impacts the ecology of molecules in headwater streams
… film that begins in upland soils and ends in streams. The fate and function of DOM in aquatic ecosystems are strongly affected by its chemical properties. Thus, recent progress in the molecular characterization of DOM has opened a new line of inquiry into harvest impacts on aquatic ecosystem …
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Linking Heterotrophic Metabolism and Nutrient Uptake in Headwater Streams
… level. We address how nutrient demand in headwater streams changes with shifts in organic matter supply and associated microbial activity by investigating these relationships in the predominantly heterotrophic conditions of a southern Appalachian stream. We measured litter input, organic …
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Effects of forest disturbance on shredder production in headwater streams
… production in disturbed versus reference forest streams. Benthic samples were collected monthly in 3 streams in a mature hardwood reference forest and 3 streams in an 11-year-old clearcut. Reference forest streams had significantly greater total leaf biomass and significantly more slow-processing …
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Determining primary drivers of river bead functionality in mountain headwater streams
I evaluated flux attenuation potential, or functionality, in laterally extensive storage-dominated reaches known as 'beads.' Beads are disproportionately important to river corridor health. Bead functionality was evaluated as a relationship between driver variables, which directly measure or …
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Livestock Exclusion Effects on the Structure and Function of Headwater Streams
The structure and function of headwater streams was evaluated in response to livestock exclusion implemented through Virginia's Conservation Reserve Enhancement Program (CREP). We measured riparian plant characteristics along with stream organic matter dynamics, benthic macroinvertebrates, algal …
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Effects of experimentally-altered hydrology on ecosystem function in headwater streams
Forested headwater stream ecosystems are important integrators of terrestrial and aquatic systems and their function depends greatly on water availability. In the southern Appalachians, models of future climate change predict alterations to the timing and intensity of storms such that most …
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Quantifying Solute and Water Fluxes in Headwater Streams Using Passive Flux Meters
… flux but have been used only very recently in streams. In this study, PFMs were deployed in the surface and subsurface of headwater stream channels to examine the efficacy of the device to quantify mean concentrations of calcium, aluminum, and sulfur in streams of the Hubbard Brook Experimental …
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Denitrification in sediments of headwater streams in the southern Appalachian Mountains, USA
… determinants of denitrification in sediments of streams in the southern Appalachian Mountains, USA. Stream water and sediments were sampled seasonally in two streams of contrasting nitrate availability, Noland Creek (high NO₃-N) and Walker Branch (low NO3-N). Eight additional streams with varying …
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Characterization of dissolved fluvial carbon from landscape characteristics across High Arctic headwater streams
… of the stream network through a watershed. Small headwater streams in the High Arctic are understudied and account for a significant amount of the freshwater geochemical flux from North America. This research investigates the concentration of fluvial dissolved organic carbon (DOC) and dissolved …
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Sample Collection and DNA Extraction Methods for Environmental DNA Metabarcoding in Headwater Streams
<p>DNA is found to be free and ubiquitous in the environment where it is no longer associated with the source organism, and is also known as environmental-DNA (eDNA). Methods optimized for specific environments may be able supplement insight to local taxa richness. With the advent of high …
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Community ecology of aquatic insects in forested headwater streams in the southern Appalachians
… processes for benthic macroinvertebrates in headwater streams in the southern Appalachians. Distance decay in taxonomic and functional similarity was used to determine the scales at which taxonomic turnover occurred within functional niches. Trait-neutral models of community composition were …
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Transport and decomposition of allochthonous litter in Icelandic headwater streams: Effects of forest cover
… a part of a larger research project entitled ForStreams. Changes in catchment vegetation can have large impacts on stream ecosystems, especially through transport of terrestrial organic matter into them. The objectives of the present study were to compare non-forested and forested catchments in …
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Multi-scale hydrogeomorphic influences on bull trout spawning habitat in snowmelt-dominated headwater streams
… in gravel-bed, pool-riffle, snowmelt dominated headwater streams of northwestern Montana. Subreach redd occurrence tended to be associated with the finest available textural facies. In subreach streambed sections hosting bull trout redds, redd density was significantly (at α=0.05) positively …
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WHAT PREDICTS TERRESTRIAL INVERTEBRATE SUBSIDY USE BY BROOK TROUT (SALVELINUS FONTINALIS) IN HEADWATER STREAMS?
… input and use of these subsidies to vary among streams. Among the watershed characteristics that may influence input and use of terrestrial invertebrates, I predicted that forest succession stage would be especially important due to differences in terrestrial invertebrate biomass in early and …
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Multi-scale hydrogeomorphic influences on bull trout spawning habitat in snowmelt-dominated headwater streams
… in gravel-bed, pool-riffle, snowmelt dominated headwater streams of northwestern Montana. Subreach redd occurrence tended to be associated with the finest available textural facies. In subreach streambed sections hosting bull trout redds, redd density was significantly (at α=0.05) positively …
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WHAT PREDICTS TERRESTRIAL INVERTEBRATE SUBSIDY USE BY BROOK TROUT (SALVELINUS FONTINALIS) IN HEADWATER STREAMS?
… input and use of these subsidies to vary among streams. Among the watershed characteristics that may influence input and use of terrestrial invertebrates, I predicted that forest succession stage would be especially important due to differences in terrestrial invertebrate biomass in early and …
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Modelling Stream Metabolism and Fish Biomass in Headwater Streams of the Eastern Cascades Mountains
Headwater streams are important for the biological integrity of river systems because they represent most of the length of the hydrological network and control the downstream flow of energy and nutrients to larger river systems. Headwater streams are culturally and economically important because …
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Impacts of aquaculture effluent on water quality and biotic communities in Virginia headwater streams
… Low fish species richness and abundance in these headwater streams limited the usefulness of the IBI. The proposed general discharge permit for aquaculture in Virginia is discussed and trout farm management and design recommendations are presented.
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INFLUENCES OF DISEASE-DRIVEN AMPHIBIAN DECLINES ON ECOSYSTEM STRUCTURE AND FUNCTION IN PANAMANIAN HEADWATER STREAMS
… biogeochemical cycling. Tadpoles in tropical streams likely regulate flows and ratios of nitrogen (N), phosphorus (P), and carbon (C), influencing ecosystems by altering nutrient supplies to other animals and their food resources. I used ecological stoichiometry as a framework to assess how …
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