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 35 for “"Number Of Taxa"”.
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Changes in colonization dynamics and community structure of protozoans and macroinvertebrates in response to stress
The response of macroinvertebrate and protozoan colonization dynamics to industrial pollution was determined in a thermal organic effluent and in a metals effluent. The relationship of the time course data to the MacArthur-Wilson model is considered, along with Pinkham and Pearson's community …
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Botanical Survey of Seven Sites Along the Jack's Fork River, Ozark National Scenic Riverways
A survey of the vascular flora of seven sites in Ozark National Scenic Riverways, Missouri, was made between 27 September 1991 and 17 September 1994. A checklist of 690 taxa representing 116 families, 377 genera, 66 Shannon County records and 20 Texas County records is included. The families with …
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Macroinvertebrate colonization and production in new experimental ponds
Benthic macroinvertebrate colonization of twelve 0.04-ha experimental ponds was studied for the 1st yr of their existence. The ponds were filled in late January 1988, and artificial substrate samples were retrieved at 4-wk intervals from February 25, 1988 to February 25, 1989. The first organisms …
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Abundance, Biomass, and Diversity of Aquatic Invertebrates in Level Ditches and Adjacent Natural Emergent Marsh in an Eastern South Dakota Wetland
The aquatic invertebrate communities of level ditches and adjacent natural emergent marsh in a South Dakota prairie wetland were sampled during the summer of 1982. Collections were made in both the water column and the bottom substrates. Forty-five taxa were collected. Analysis of variance …
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Algal Biodiversity Survey of the Middle Chattahoochee River Using DNA Metabarcoding
… metabarcoding, where DNA belonging to specific taxa can be isolated and identified from water samples. The objective of this study was to conduct an algal biodiversity survey on the middle Chattahoochee River system in Georgia. Water samples (1L) were filtered and sent to RTL Genomics for …
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Feeding Ecology of Fishes in a South Dakota Power Plant Cooling Reservoir
<p>The food habits of bluegills (Lepomis macrochirus), black bullheads Ictalurus melas), and muskellunge (Esox masquinongv) in the Big Stone Power Plant cooling reservoir were studied from January through December 1979. The diet of 794 bluegills >50 mm TL was dominated by vegetation, planktonic …
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Recovery of community structure and leaf processing in a headwater stream following use of a wetland passive treatment system to abate copper pollution
… In kick samples, insect abundance (n) and the number of taxa (#) were reduced at the impacted sites (n = 31, 22, 33, 24 and # = 190, 246, 266, 345, at sites 2 - 5, respectively) relative to the reference site (n = 52, # = 973). Red maple (Acer rubrum) leaves broke down twice as fast at the …
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Estimating Embeddedness From Bankfull Shear Velocity in Gravel Streambeds to Assess Sediment Impacts on Aquatic Biota
… (<2mm in diameter) impairs over 40,000 miles of streams in the U.S., degrading habitat quality for many aquatic species. Embeddedness (emb, %), a measure of fine sediment in gravel bed streams, is negatively correlated with bankfull shear velocity (u*, m/s). This relationship can be modeled by …
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The role of Marine Renewable Energy structures and biofouling communities in promoting self-sustaining populations of Non-Native Species
… created by the large-scale deployment of Marine Renewable Energy Devices (MREDs) have the potential to promote the spread of non-native species (NNS). Knowledge of how community composition resident on MREDs is shaped by geography, local hydrodynamics and the duration of deployment, …
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Changes in the invertebrate populations, fish populations, and water chemistry of a small stream above and below two impoundments
… with the ponds appeared to be an alteration of energy dynamics. The alterations were seasonally dependent, and may have resulted from interception of larger particle organic matter being transported downstream and its replacement by finer organic matter. The alterations manifested themselves …
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Using a complex model of sequence evolution to evaluate and improve phylogenetic methods
The performance of phylogenetic methods was evaluated by testing their success in recovering the true tree from computer simulated data. Data were generated on a variety of tree shapes under a complex model of sequence evolution based on the work of Aaron Halpern and William Bruno. Parameters of …
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Biological assessment of tropical riverine systems using aquatic macroinvertebrates in Tanzania, East Africa
… in place. This thesis describes the development of a macroinvertebrate-based bioassessment method for assessing the degree of anthropogenic disturbance in Tanzanian rivers. The hypotheses that, 'macroinvertebrate assemblages reflect disturbance in river systems'; 'rivers with similar abiotic …
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An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality
… bioassessment technique based on one component of riverine biotas, the benthic macroinvertebrates. Each taxon is assigned a tolerance/sensitivity score, which are summed to provide a Total Score. The Average Score per Taxon (ASPT) is calculated by dividing this Total Score by the number of taxa. …
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Mitochondrial DNA analysis of the evolution and genetic diversity of ancient and extinct bears.
Mitochondrial phylogeographic analyses of modern populations can be used to make inferences about the impacts of the last glacial maximum (LGM) and anthropogenic disruption on late Pleistocene and Holocene ancestral populations. However, it is becoming more and more evident that ancient DNA studies …
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Community responses of aquatic macroinvertebrates to heavy metals in laboratory and outdoor experimental streams
… reduced macroinvertebrate abundance and number of taxa during each season. Owing to differences in sensitivity among taxa, the percent composition of dominant groups varied between control and dosed streams. Mayflies were quite sensitive to Cu, particularly during the summer when water …
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Ecology of benthic macroinvertebrates in experimental ponds
I studied life history parameters of 5 taxa of aquatic insects in the orders Ephemeroptera and Odonata, successional patterns over 2 years of pond development, and precision of 15 biological metrics in a series of 6 replicate experimental ponds from March 1989 to April 1990. I determined voltinism, …
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Effects of watershed land use on the benthic macroinvertebrate assemblages in ridge and valley streams in Chattanooga, Tennessee
A total of 20 sites in five Ridge and Valley streams located in Chattanooga, Tennessee were sampled May 8, 1998 to June 18, 1998 using quantitative and qualitative macroinvertebrate sampling techniques. All streams sampled were part of the Tennessee River drainage system and eventually contribute …
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Potent but forgotten: nitrous oxide contributions by an ascidian on warming reefs
Increasing emissions of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are driving global climate change and greatly impacting ecosystems. Although N2O has approximately 300 times the warming potential of carbon dioxide, mitigation strategies are lagging in …
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Biosystematics and Diversification in the Genus <i>Striga Lour.</i> (Scrophulariaceae) in Africa
<p>Of the 34 taxa of <em>Striga</em> (29 species) that occur in Africa, 25 are endemic. Species diversity differs from region to region. The subtropical zone has 74% of the taxa including 41% endemics. Within this region, the West African part (from Senegal to eastern Nigeria) has 62% of the total …
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Endophytic fungi of Cassia fistula L.
… a natural forest situation provided the highest number of isolates with Bangkok, where the trees were isolated individuals, having the least. Members of the Xylariaceae proved to be common and frequent isolates especially species of Xylaria and Daldinia but Nemania and Hypoxylon were also …
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