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The Global ETD Search service is a free service for researchers
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Showing 21 to 28 of 28 (0.057 seconds)Spelling suggestions: "subject:"biotic integrity"" "subject:"biotic ntegrity""
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Development of a diatom based index of biotic integrity for acid mine drainage impacted streamsZalack, Jason T. January 2006 (has links)
No description available.
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An Index of Biotic Integrity for Macroinvertebrates and Salamanders in Primary Headwater Habitat Streams in OhioMoore, Edward L., Jr. 15 January 2010 (has links)
No description available.
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| 23 |
Integrating GIS with Benthic Metrics: Calibrating a Biotic Index to Effectively Discriminate Stream Impacts in Urban Areas of the Blackland Prairie Eco-RegionEarnest, Steven F. P. 12 1900 (has links)
Rapid Bioassessment Protocols integrate a suite of community, population, and functional metrics, determined from the collection of benthic macroinvertebrates or fish, into a single assessment. This study was conducted in Dallas County Texas, an area located in the blackland prairie eco-region that is semi-arid and densely populated. The objectives of this research were to identify reference streams and propose a set of metrics that are best able to discriminate between differences in community structure due to natural variability from those caused by changes in water quality due to watershed impacts. Using geographic information systems, a total of nine watersheds, each representing a different mix of land uses, were chosen for evaluation. A total of 30 metrics commonly used in RBP protocols were calculated. Efficacy of these metrics to distinguish change was determined using several statistical techniques. Ten metrics were used to classify study area watersheds according to stream quality. Many trends, such as taxa presence along habitat quality gradients, were observed. These gradients coincided with expected responses of stream communities to landscape and habitat variables.
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IMPORTANCE OF TOTAL SUSPENDED SOLIDS IN EXPLAINING FISH COMMUNITY STRUCTURE IN AGRICULTURAL HEADWATER STREAMSJennifer L Troy (7042787) 16 October 2019 (has links)
<div>Agricultural headwater streams in the Midwestern United States are subject to contaminants from fields, increased sedimentation, and degradation of natural habitat. Previous research has shown that physical instream habitat degradation better explained variation in fish community structure than water chemistry. However, these studies did not include total suspended solids (TSS), which are considered a major freshwater contaminant. The objective of this study is to determine whether total suspended solids better explains fish community structure than other variables in agricultural headwater streams. Mixed linear effects modeling was used to determine the set of independent variables that best predicts each of the fish response variables of species richness, Shannon diversity index, fish density, and index of biotic integrity. Standardized coefficients were used to determine which independent variable in each of the models had the largest influence on fish response metrics. The set of independent variables that best explained species richness were mean total suspended solids, imidacloprid, discharge, and substrate richness. Shannon diversity index was explained best by the combination of maximum total suspended solids, mean total suspended solids, atrazine, total nitrogen, and discharge. Fish density was explained best by the percentage of silt and clay, dissolved oxygen, the percentage of canopy cover, cover type richness, and discharge. IBI was explained best by the combination of the percentage of silt and clay, total phosphorus, mean total suspended solids, and dissolved oxygen. Total suspended solids was the most influential independent variable for fish species richness and Shannon diversity, however the percentage of silt and clay in benthic sediments was the most influential independent variable for fish density and IBI. Results also indicate discharge and total phosphorus as being influential to fish community metrics. The results from this study suggest that models containing a combination of different types of independent variables best explain fish community structure. This study supports the use of conservation and restoration practices that reduce total suspended solids and the amount of silt and clay present in bed sediments to increase fish community integrity of agricultural headwater streams of the Midwestern United States.</div>
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| 25 |
The political economy of ecological research analyzing the "total maximum daily load" process in the upper Mill Creek (Cincinnati) /Stone, Harry James. January 2004 (has links)
Thesis (Ph. D.)--Miami University, Dept. of Botany, 2004. / Title from second page of PDF document. Includes bibliographical references.
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| 26 |
Effects of Water Quality, Instream Toxicity, and Habitat Variability on Fish Assemblages in the Trinity River, TexasArnold, Winfred R., 1960- 12 1900 (has links)
The Trinity River flows through the Dallas-Ft. Worth Metroplex in north central Texas where it receives effluents from numerous point sources including seven large regional wastewater treatment facilities. Historically, the Trinity River has been impacted by massive wastewater loadings which often constitute > 80% of the total river discharge during low flow periods. Normally, high mass loadings correspond to the summer months, compounding the effects of a naturally stressful period, characterized by high temperatures and low dissolved oxygen concentrations.
Samples from 12 stations were collected quarterly over an 18 month period from the Trinity River and two tributaries. Water samples were analyzed for a variety of water quality variables, including metals, priority pollutants, pesticides, and general water quality parameters. Water samples were also tested for acute and subchronic effects with several test species. Fish were collected at each station and assemblages were characterized using traditional classification techniques and the Index of Biotic Integrity. In addition, sediment samples were assessed for toxic effects which could have adversely
impacted fish recruitment and in situ biomonitoring experiments were performed. Quantitative habitat characterization analyses were performed to gain additional information that could possibly explains differences in fish assemblage structure related to habitat variability.
Data were analyzed using regression, univariate, multivariate, and descriptive statistical techniques and new approaches for analyzing impact assessment data were discussed. Results indicated that the most substantial impacts on fish assemblages were confined to a segment of the river where a sequence of point sources, in close proximity to each other, were overloading the river's capacity to sufficiently dilute and/or detoxify the effluent. Data also indicated the presence of episodic toxicity from nonpoint sources. In addition, toxic effects in sediment samples and differences in habitat were detected and may have contributed to measured differences among fish assemblages in the Trinity River.
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| 27 |
LAND COVER AND STREAM BIOLOGICAL INTEGRITY IN NORTH-CENTRAL INDIANAAlexandra Ann Adams (18066691) 28 February 2024 (has links)
<p dir="ltr">The Temperate Plains ecoregion of Indiana has experienced significant agricultural development since the 19th century, which has left streams vulnerable to impacts such as sedimentation and nutrient accumulation. This thesis describes first the accuracy of the USDA Cropland Data Layer (CDL) in land cover change, and second, the relationships between agricultural and forested land covers and stream biological integrity. I first employed the CDL to review land cover change, particularly relating to agriculture and forest, for the area of interest between 2010 and 2020. I determined that the CDL improved in accuracy for the area of interest in the chosen timeframe for non-agricultural and non-forest land cover. I concluded that the CDL was best used as a supplement to primary-source land cover measures. Next, I calculated the fish Index of Biotic Integrity (IBI) scores for 20 sampled agricultural and forested streams in North-Central Indiana. I also assessed the stream habitats at all sites using the Qualitative Habitat Evaluation Index (QHEI) and percent cultivated crops in drainage basin areas for all streams. Forested streams had significantly higher QHEI scores than agricultural streams (median = 62 and 40.4, respectively). No other relationships were statistically different, including IBI and land cover category, which may have been due to the small sample size (n = 20). I concluded that future studies may build on these findings by controlling for agricultural drainage types or using precise measures of forested land cover.</p>
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| 28 |
The Effect of Dredging on Fish Communities in Agricultural Streams in Crawford, Sandusky and Seneca Counties of Ohio.Selden, Justin D. 27 November 2013 (has links)
No description available.
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