Dissertations / Theses on the topic 'Benthic macroinvertebrates'
To see the other types of publications on this topic, follow the link: Benthic macroinvertebrates.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Benthic macroinvertebrates.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Christman, Van D. "Ecology of benthic macroinvertebrates in experimental ponds." Diss., This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134927/.
Full text
2
Johansson, Andreas. "Effects of beaver dams on benthic macroinvertebrates." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-396803.
Full textAbstract:
In the 1870's the beaver (Castor fiber), population in Sweden had been exterminated. Thebeaver was reintroduced to Sweden from the Norwegian population between 1922 and 1939.Today the population has recovered and it is estimated that the population of C. fiber in all ofEurope today ranges around 639,000 individuals. The main aim with this study was toinvestigate if there was any difference in species diversity between sites located upstream anddownstream of beaver ponds. I found no significant difference in species diversity betweenthese sites and the geographical location of the streams did not affect the species diversity.This means that in future studies it is possible to consider all streams to be replicates despiteof geographical location. The pond age and size did on the other hand affect the speciesdiversity. Young ponds had a significantly higher diversity compared to medium-aged ponds.Small ponds had a significantly higher diversity compared to medium-sized and large ponds.The upstream and downstream reaches did not differ in terms of CPOM amount but somewater chemistry variables did differ between them. For the functional feeding groups I onlyfound a difference between the sites for predators, which were more abundant downstream ofthe ponds.
3
Gabel, Friederike. "Impacts of ship-induced waves on benthic macroinvertebrates." Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2012. http://dx.doi.org/10.18452/16498.
Full textAbstract:
Schifffahrt stellt weltweit eine der wichtigsten Nutzungen der Flüsse und Seen dar, die zukünftig weiter zu nimmt. Sie schädigt Ufer durch Wellenschlag erheblich. Die Effekte von Schiffswellen auf benthische Wirbellose sind aber bisher kaum bekannt, obwohl diese eine zentrale Rolle im litoralen Nahrungsnetz spielen. Daher untersuchte ich 1) die direkten Effekte von Schiffswellen auf benthische Wirbellose, 2) die resultierenden Auswirkungen auf trophische Interaktionen und 3) das Wachstum und die Fitness von Wirbellosen, sowie 4) die langfristigen Änderungen der litoralen Wirbellosenzönosen. Labor- und Feldversuche zeigten, dass mit zunehmender wellengenerierter Sohlschubspannung mehr Individuen verdriftet wurden. Die Verdriftung wurde jedoch durch eine hohe strukturelle Habitatkomplexität gemindert, da diese die Wellenenergie stärker dissipierte und den Wirbellosen bessere Festhaltemöglichkeiten bot. Die Verdriftung der Wirbellosen bewirkte ein höheres Prädationsrisiko durch spindelförmige Fische, während hochrückige Fische die Ingestion bei Wellenexposition reduzierten. Wellenschlag verringerte auch das Wachstum und die Fitness nativer Wirbellosenarten, indem die Ingestion verringert oder der Energieverbrauch erhöht wurde, wohingegen Neozoen nicht beeinträchtigt wurden. Der kumulative Effekt von Schiffswellen veränderte die Artenzusammensetzung benthischer Zönosen sehr. Die Abundanz nativer Wirbelloser und die Artenzahl waren an exponierten Ufern geringer, während die Abundanz invasiver Arten zunahm. Folglich beeinträchtigen Schiffswellen benthische Wirbellose auf der Ebene der Individuen, Arten, Zönosen, sowie tropischer Interaktionen, und können so die ökologische Struktur und Funktion des gesamten Litorals beeinflussen. Durch Schutz komplexer Habitate wie Wurzeln und dichte Schilfbestände, sowie durch Wellenschlagsreduzierung durch größere Mindestabstände zum Ufer und angepasste Fahrtgeschwindigkeit, können die Auswirkungen von Schiffswellen gemindert werden.Inland navigation is a major human use of rivers and lakes worldwide which is expected to increase in the future. It significantly affects shore habitats by ship-induced waves. In contrast to the importance of such pressures, the effects of these hydrodynamic disturbances on benthic invertebrates in the littoral zones are poorly understood, even that invertebrates are a central element of littoral food webs. Hence, I investigated 1) the direct and immediate effects of ship-waves on benthic invertebrates, 2) their subsequent effects on trophic interactions and 3) on the growth and fitness of invertebrates, and finally 4) the long-term effects on the community composition. Laboratory and field experiments showed increasing detachment of invertebrates with higher wave-induced shear stress. Detachment was significantly mitigated by higher structural complexity of the habitats, as complex habitats dissipate wave energy and provide better fixing possibilities. Moreover dislodgement of invertebrates led to a higher risk of being preyed upon by fusiform fish, while deep bodied fish reduced feeding under waves. Waves also reduced growth and fitness of native invertebrates via reduced feeding or increased energy costs, while non-native invertebrates were not affected. The cumulative impact of ship-waves alters the community composition of benthic invertebrates. The abundance of native invertebrates and total species richness was lower at exposed sites, while non-native invertebrates increased in abundance. Thus, ship-waves affect benthic invertebrates on the individual, species, and community levels, as well as the interaction of trophic levels, and hence will alter the ecological structure and function of whole littoral zones. Adverse effects of ship-waves may be mitigated by protecting structural complex habitats such as tree roots and dense reed belts, and by minimizing wave generation by increasing minimum sailing distance to shore or by adjusting vessel speed.
4
Garey, Andrew L. "The Effects of Hydropeaking on Lotic Benthic Macroinvertebrate Assemblages." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4057.
Full textAbstract:
The term hydropeaking refers to anthropogenically induced, short-duration, high-magnitude discharge pulses that are generated in lotic systems for electricity production. The practice of hydropeaking produces the largest source of renewable energy worldwide, and its use is projected to increase through the year 2040. The primary objective of this work was to evaluate the effects of hydropeaking on benthic macroinvertebrate assemblages, which are important components of lotic ecosystems. Results of this work show that, across a wide range of impacted systems worldwide, the consistently observed patterns of elevated benthic macroinvertebrate drift in response to hydropeaking pulses are primarily related to the rate at which discharge is increased (i.e., ramping rate) and secondarily to the time between pulses. In addition, it was shown that taxa inhabiting depositional habitat patches (i.e. fine substrates and slow water velocities) were most susceptible to peaking-induced drift, and that these taxa were also those most prevalent in hydropeaking-impacted systems. Collectively, these results suggest that increased pulse ramping rate and the resulting elevated macroinvertebrate drift may be positive selective forces, which benefit populations adapted for life in hydropeaking-impacted lotic ecosystems. These results provide a greater understanding of the factors that are most important for governing the effects of hydropeaking on benthic assemblages.
5
O'Hare, Matthew Thomas. "Flow preferences of benthic macroinvertebrates in three Scottish rivers." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312705.
Full text
6
Song, Mi-Young. "Ecological quality assessment of stream ecosystems using benthic macroinvertebrates." Toulouse 3, 2007. http://thesesups.ups-tlse.fr/224/.
Full textAbstract:
Dans cette étude, nous avons appliqué le modèle SOM (Self-Organizing Map) pour une évaluation de la qualité écologique de l'écosystème aquatique en se basant sur les macroinvertébrés benthiques. D'abord, dans le chapitre I, le SOM a été utilisé pour extraire les informations à partir de grandes matrices de données complexes de variables environnementales et des macroinvertébrés benthiques des différents microhabitats. Bien que les échantillonnages aient e��té réalisés dans une zone limitée, le patron des variables environnementales révèle une hétérogénéité spatiale. Les classes de macroinvertébrés dans le modèle SOM ont montré une variation temporelle et permettent l'évaluation de la qualité de l'eau en accord avec les conditions des différents microhabitats. En conséquence, l'hétérogénéité spatiale locale est importante en révélant les dynamiques des communautés et les indices biotiques, particulièrement en rapport avec le processus de restauration des rivières polluées. Dans le chapitre II, les échantillons ont été classés en 3 groupes principaux par le modèle SOM pour distinguer les assemblages EPTC (Ephéméroptères, Plécoptères, Trichoptères, Coléoptères) dans les cours d'eaux du Coteau de Gascogne, tributaires de la Garonne (sud-ouest France). Des faibles richesses et diversités ont été observées dans cette zone affectée par une pratique agricole intensive, caractérisée par de très fortes valeurs de TDS (Total Dissolved Solids), nitrate (NO3) et COD (Chemical Oxygen Demand). Les espèces EPTC tolérantes ont été utilisées comme paramètres de contrôle pour les changements d'assemblage de communautés collectées dans des sites impactés par la pratique agricole. .In this study, we applied the SOM for ecological assessment using benthic macroinvertebrates in aquatic ecosystem. First, Chapter I, SOM was utilized to extract information from complex data of environmental variables and benthic macroinvertebrate communities residing in different micro-habitats. Although the sampling was carried out in a limited area, the patterns of environmental variables revealed spatial heterogeneity. The clustering of benthic macroinvertebrate communities in the trained SOM was efficient in showing temporal variation and evaluating water quality according to the conditions of different micro-habitats. Consequently, local spatial heterogeneity is important in revealing dynamics of community abundance and biotic indices, especially regarding restoration processes in polluted streams. Chapter II, the samples were grouped into three main clusters corresponding to distinc EPTC assemblages in the tributary streams of the Garonne River catchment, southern France. Lower richness and diversity of macroinvertebrates were observed in the areas affected by agricultural land use, being associated with high Total Dissolved Solids (TDS), Nitrate (NO3) and Chemical Oxygen Demand (COD). Tolerant EPTC species were identified as controlling parameters for the changes in the assemblages collected at the agricultural-impacted sites. .
7
Roberts, Lenn Darrell. "Benthic Macroinvertebrate Susceptibility to Trout Farm Effluents." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/35004.
Full textAbstract:
The direct effects of a Virginia trout farm on benthic macroinvertebrates were examined using multiple approaches. Static laboratory tests with the amphipod, Hyallela azteca, were conducted with exposures to water taken from a spring, effluent above a sedimentation basin, and effluent below a sedimentation basin. On-site mesocosms were constructed to expose previously colonized artificial substrates to the same treatments as the laboratory tests. Flat-headed mayflies were also collected from a nearby stream and transported to the mesocosms for a 10 day exposure. There was no significant difference between treatments in the laboratory tests after 20 days, but after 28 days the control was significantly lower than the above sedimentation basin treatment in one test. In the multispecies field tests, a clear decrease in total invertebrate abundance and EPT abundance was seen in the effluent treatments compared to the spring water treatments, with a slight improvement in survival in the treatment below the sedimentation basin. However, only total invertebrate abundance after 21 days produced statistically significant differences. A significant difference was detected between the effluent and the spring treatments in the flat-headed mayfly field test. We suggest that the effects seen in this study do not explain the lack of taxa richness in the receiving stream. The main cause of mortality from trout effluents appears to be solids accumulating upon the organisms, and sedimentation basins should be effective best management practices for protecting macroinvertebrates.Master of Science
8
Foster, Carole A. "Benthic macroinvertebrates in Uvas Creek, California, downstream of a reservoir." Thesis, San Jose State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1583489.
Full textAbstract:
I sampled macroinvertebrates in May, July, and October 2008 in Uvas Creek, a reservoir-regulated stream in south Santa Clara County, California, to assess what factors (including canopy closure, turbidity, and stream flow) downstream of the reservoir were related to food availability for rearing juvenile Steelhead (Oncorhynchus mykiss). I found benthic and drifting macroinvertebrate biomass was considerably greater during most months in the more open-canopied two sites in the downstream reach as compared to the densely shaded, more turbid and silty two sites in the upstream reach. Abundance of important drifting aquatic invertebrates in May (chironomids, simuliids, and baetids) was proportional to benthic abundance, but large hydropsychids were relatively scarce in the drift. Terrestrial drift abundance correlated with canopy density, but differences were small compared to the substantial increase in aquatic drift in sunnier sites. Thinning of the canopy at select locations and reduction of sediment input to Uvas Creek and its tributaries due to vineyard and other operations could increase benthic macroinvertebrate productivity in the upstream reach, which would increase food availability for rearing juvenile Steelhead.
9
Kaller, Michael D. "Effects of sediment upon benthic macroinvertebrates in forested northern Appalachian streams." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1862.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2001.Title from document title page. Document formatted into pages; contains x, 157 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references.
10
McNish, Julie Helen. "An interdisciplinary assessment of variations in acidity in Yorkshire rivers, with special reference to episodic acidification of headwaters in the Esk catchment." Thesis, University of Huddersfield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285628.
Full text
11
Béjar, Maceiras María. "Interactions between sediment transport, physical habitat and benthic communities in a mountainous river affected by natural and human disturbances." Doctoral thesis, Universitat de Lleida, 2018. http://hdl.handle.net/10803/664346.
Full textAbstract:
Aquesta tesi presenta noves idees sobre les interaccions entre processos físics (transport de sediments, cabal i hàbitat) i ecològics (comunitats bentòniques, deriva de macroinvertebrats) resultants de pertorbacions naturals (afluents, riuades) i antròpiques (extraccions d’àrids a la llera i hidro-puntes o embolades) en un riu de muntanya (tram alt del riu Cinca, vessant Sud dels Pirineus). S’analitzen processos i interaccions a múltiples escales temporals (des de l’escala instantània a l’anual) i espacials (des del nivell de partícula fins el tram fluvial). La identificació de les escales d’interacció, així com l’ús de noves tècniques de mostreig han demostrat ser rellevants per a l’estudi de la relació espècie-hàbitat i constitueixen, conseqüentment, un nou exemple d’integració eco-geomorfològica que permet millorar el coneixement dels sistemes fluvials i recolza la gestió sostenible dels ecosistemes associats.Esta tesis doctoral analiza las interacciones entre los procesos físicos (transporte de sedimentos, caudal y hábitat) y ecológicos (comunidades bentónicas, deriva de macroinvertebrados) afectados por perturbaciones naturales (crecidas y entrada de afluentes) y antrópicas (extracción de áridos e hidropuntas) en un rio de montaña (el alto Cinca, en el sur de los Pirineos). Dichos procesos y sus interacciones se han evaluado desde una escala instantánea hasta anual, y desde la escala de partícula a la escala de tramo. La identificación de las escalas de interacción así como el uso de nuevas técnicas de muestreo han demostrado ser relevantes para el estudio de la relación especie-hábitat y constituyen, por ello, un nuevo ejemplo de integración eco-geomorfológica que contribuye al conocimiento de los sistemas fluviales y apoya la gestión sostenible de los mismos.
This doctoral thesis presents new insights on the interactions between physical (sediment transport, flow and habitat) and ecological (benthic communities, macroinvertebrate drift) processes driven by natural (tributaries, floods) and human disturbances (gravel mining and hydropeaking) in a montane river (the upper Cinca, Southern Pyrenees). The work addresses processes and interactions spanning instantaneous to annual temporal scales, and from grain to river reach scale. Identification of the key scales of interaction and the integration of sampling techniques that provide continuous and high density measurements are shown to provide sound knowledge into species-habitat relations and, in turn, a firm evidence supporting the rational assessment and sustainable management of fluvial ecosystems.
12
Khan, Muhammad Irfan. "A lotic microcosm for ecological and ecotoxicological studies on benthic macroinvertebrates." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320214.
Full text
13
Neale, Martin William. "Classifying and measuring the ecological status of lakes using benthic macroinvertebrates." Thesis, University of Ulster, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414101.
Full text
14
Tharme, Rebecca Elizabeth. "Ecologically relevant low flows for riverine benthic macroinvertebrates: characterization and application." Doctoral thesis, University of Cape Town, 2010. http://hdl.handle.net/11427/11040.
Full textAbstract:
Intensifying hydrologic alteration and the resultant degradation of river ecosystems worldwide have catalyzed a growing body of ecohydrological research into the relationships between flow regime attributes, physical habitat dynamics and biotic response, particularly for determining environmental flows. While invertebrate response to floods has received most attention, in this thesis the aim was to identify and characterize low flows that constituted various degrees of physical disturbance to benthic macroinvertebrate assemblages of perennial rivers.
15
McTammany, Matthew Eric Jr. "The Impact of Urbanization on Benthic Macroinvertebrates in Southern Appalachian Streams." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/46508.
Full textAbstract:
Macroinvertebrate assemblage structure was compared from 12 streams differing in urbanization type and degree. Urbanization, both historical and current, was measured using several variables generated from GIS overlays of land cover, aerial photographs, and field exploration in the study watersheds. Quantitative benthic macroinvertebrate samples were taken, and a variety of physicochemical characteristics were measured. Increasing urbanization resulted in a decline in diversity and abundance of intolerant organisms. Streams in industrial areas had greater invertebrate density due to large increases in a few tolerant groups. Urbanization in the watersheds was coupled with changes in the physical and chemical structure of the streams suggesting some possible mechanisms for urbanization impact on stream biota. Multivariate analysis grouped streams based on a number of pollution-sensitive taxa suggesting the utility of this type of approach in analyzing community data.
Primary funding for this project was from the Coweeta Hydrologic Lab NSF-LTER grant. Additional funding was provided through a Graduate Research and Development Project grant from the Graduate Student Assembly of Virginia Polytechnic Institute and State University. Matching funds were provided by the Biology Department.Master of Science
16
Eby, Gloria. "TMDL BIOASSESSMENT SAMPLING OF BENTHIC MACROINVERTEBRATES FOR LAKE JESUP AND LAKE SEMINARY." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3899.
Full textAbstract:
The objective of this study was to obtain a bioassessment using benthic macroinvertebrates to meet TMDL (Total Maximum Daily Load) criteria for an oligotrophic (Lake Seminary) and an eutrophic (Lake Jesup) freshwater system in Seminole County, Florida. Monthly sampling of the benthic macroinverterbrate communities provided important biological data necessary to construct TMDL protocol and trophic state. Since macroinvertebrates are near the base of the food chain, they not only provide a critical role in the natural flow of energy and cycling of nutrients through the food web, but also provide a good indication of water quality by their presence and abundance. This study suggests that TMDL protocol and reversal trends in eutrophication can be successfully monitored using benthic macroinvertebrate data. Comparative methodology between the LCI and conventional methods indicate that the LCI is a valid, cost-effective and rapid bioassessment method when compared to the conventional method and that the conventional method is an effective tool when more in depth benthic studies are needed as it shows distinct seasonal patterns and accounts for more of the sensitive, intolerant taxa. Furthermore, this type of biological monitoring and trend analysis aids in the implementation of anthropogenic controls that targets waters for TMDLs in suspect systems. When integrated within a watershed management plan, multi-metric indexing functions as an effective overall indicator of the biological condition within a waterbody responding to its watershed.M.S.
Department of Biology
Sciences
Biology MS
17
Lage, Fernanda. "Aplicação da tríade de qualidade do sedimento em análise espacial no reservatório do Guarapiranga (SP, Brasil)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-19032014-141437/.
Full textAbstract:
Com o intuito de conhecer o histórico da comunidade bentônica no reservatório do Guarapiranga para futuro estudo sobre a influência das diferentes formas de poluição na represa sobre o zoobentos, este trabalho foi desenvolvido a fim de coletar dados históricos da fauna de fundo e se houve variação na estrutura da comunidade ou não. Foram analisados quatro trabalhos realizados no período de inverno em quatro regiões médio-profundal do reservatório (Guarapiranga, Embu-Mirim, Embu-Guaçu e Parelheiros) ao longo dos anos, 1939, 1976, 1996 e 2010. A riqueza de dados presentada nos trabalhos refletiu a evolução do conhecimento em estudos limnológicos no Brasil e no mundo. A densidade de Oligochaeta apresentou aumento ao longo dos anos, assim como a de Chaoboridae. Por outro lado, Chironomidae que apresentava 30% em 1974 é pouco representativo em 2010. O ambiente mostrou forte e crescente enriquecimento orgânico em todos os pontos ao longo dos anos e isso colaborou para uma maior diversidade de grupos detritívoros (Tubificinae e Naidinae - Oligochaeta), por exemplo. Os níveis de oxigênio dissolvido no fundo diminuíram ao longo dos anos em todos as regiões. Chama-se a atenção para a necessidade de biomonitoramento nas 4 regiões da represa, utilizando inclusive os macroinvertebrados bentônicos e análises físicas e químicas do sedimento e a adoção de uma nova forma de gerenciamento deste manancialWith the purpose to know the history of the benthic community in Guarapiranga reservoir for future study about the influence of different sources of pollution in the reservoir over zoobenthos, this study was conducted to collect historical data of benthic fauna and variation in community structure. Four studies conducted during winter in four regions of the reservoir medium-profundal (Guarapiranga, Embu-Mirim, Embu-Guaçu and Parelheiros) over the years, 1939, 1976, 1996 and 2010 were analysed. The best richness of data presented in the works reflected the evolution of knowledge in limnological studies, in Brazil and worldwide. The density of Oligochaeta had an increase over the years as well as the Chaoboridae. On the other hand, Chironomidae presented 30% in the 70\' community and was not representative anymore in 2010. The environment showed strong organic enrichment for all regions along the years, and this has contributed to a greater diversity of detritivorous groups (Tubificinae and Naidinae - Oligochaeta), for example. The dissolved oxygen levels at the bottom declined over the years in all regions. Attention is called to the necessity of biomonitoring in 4 regions of the reservoir, using benthic macroinvertebrates and physical and chemical sediment analyses and the adoption of a new way of managing this system
18
Eliason, Kevin Matthew. "The Short Term Responses of Benthic Macroinvertebrates to the Removal of Riparian Rhododendron in Southern Appalachian Streams." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/77931.
Full textAbstract:
The southern Appalachian forests of the United States are undergoing changes due to the death of hemlock trees attacked by the hemlock wooly adelgid. This paper addresses the management impacts of Rhododendron maximum removal in the riparian and upslope areas previously occupied by hemlock. This study measured the consequences macroinvertebrates faced due to riparian Rhododendron removal from 300 m reaches of two low order streams. Two additional low order streams served as reference sites for the experiment. The stream macroinvertebrate communities were assessed using a before-after controlled impact model comparing communities between fall 2014 to those from fall 2015 and from spring 2015 to spring 2016. Macroinvertebrate collections consisted of 288 samples with a total of 61,056 individuals. There was a significant increase in collector-gathers in both removal sites, mostly from increases in Ephemerellidae and Chironomidae. There was also a significant decrease in filter feeding organisms in the removal reaches. Traits analysis also revealed that several traits that are shared by collector gathers also increased, e.g., short life cycles that are related to the increase in Chironomidae. Using Nonmetric Multidimensional Scaling (NMDS) and permutational MANOVA significant annual differences in macroinvertebrates were found in all of the stream reaches during both seasons. However, the trait based NMDS and permutational MANOVA found significant change only in one removal site between fall collections based on traits. These finding are consistent with findings from logging and other riparian removal projects; suggesting that the short-term impacts of selective Rhododendron removal on benthic macroinvertebrates are comparable to that of logging activity.Master of Science
19
Sandin, Leonard. "Spatial and temporal variability of stream benthic macroinvertebrates : implications for environmental assessment /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-6056-5.pdf.
Full text
20
Irving, Katherine Sarah [Verfasser]. "Improvement of Global Change Projections for Riverine Benthic Macroinvertebrates / Katherine Sarah Irving." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1214641342/34.
Full text
21
Little, Sally. "The impact of increasing saline penetration upon estuarine and riverine benthic macroinvertebrates." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/9737.
Full textAbstract:
Coastal and estuarine systems worldwide are under threat from future global climate change, with potential consequences including increased penetration of tidal driven salt water into estuarine surface waters. In coastal climate change research this issue has been neglected, despite increases in salinity potentially detrimentally impacting upper estuarine and riverine ecosystem function worldwide. In this research the first direct attempt is made at predicting the impact of future climate-driven increases in saline penetration upon estuarine and riverine benthic macroinvertebrate communities through the acute salinity tolerances of selected species. Two study estuary-river systems were selected based upon their perceived susceptibility to future increases in saline penetration. These estuaries exhibited dynamic tide and salinity profiles with large salinity ranges recorded over a tidal cycle and significant differences in saline penetration extents between low (summer) and high (winter) freshwater river discharge conditions. Salinity was shown to be the dominant environmental variable driving benthic macroinvertebrate species distributions in both estuaries; however additional environmental factors were shown to have locally dominant effects (i.e. sediment grain size). Laboratory and field based salinity toxicity experiments suggested that the tolerance of euryhaline-marine and brackish water species to reductions in salinity corresponded well to tolerance values in published literature. In contrast limnic derived species exhibited greater salinity tolerance under laboratory and field tidal cycle conditions than those published. For all test species, actual field distributions did not reflect distributions anticipated by saline tolerances alone, likely due to the effects of additional biotic and abiotic factors experienced under field conditions. The macroinvertebrate species salinity tolerances did not account for actual field distributions with sufficient accuracy to allow for precise prediction of future distribution patterns under projected saline penetration profiles due to the influence of additional environmental factors. Under the high greenhouse gas emissions climate scenario (SRES A1FI) for the years 2020, 2050 and 2080, projected relative sea level rise was shown to result in an increase in both the upstream extent of saline penetration and gradient of maximum salinity zones in both estuaries. However these increases were moderate even under worst-case conditions (0.32 km and 0.15 km) and unlikely to result in large-scale changes to the benthic macroinvertebrate community. However, in addition to relative sea level rise, predicted changes to freshwater river discharge (climatic and anthropogenic induced) and channel morphology could result in significant increases in the upstream extent of saline penetration predicted for projected sea level rise alone. This could result in critical consequences for estuarine and riverine ecology and ecosystem function across all trophic levels. A conceptual model exploring the potential ecological effects of both increases in saline penetration and changes to the estuarine system (anthropogenic and climatic) was developed, and implications for the future management of estuarine and riverine environments were identified.
22
Freeman, Emily K. "Effects of Dreissenid Mussel Druses on Heavy Metals Transfer via Benthic Macroinvertebrates." Bowling Green State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1372077038.
Full text
23
Sullivan, Joseph C. "Contemporary assessment of benthic macroinvertebrates and fish interactions in the Truckee River, NV." abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1472981.
Full text
24
Amos, Katlyn L. "Investigating Historical and Contemporary Land Cover Effects on Macroinvertebrate Communities and Water Quality of Virginia Piedmont Streams." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/50513.
Full textAbstract:
I investigated the relationships between historical and contemporary land cover and macroinvertebrate communities, water quality, and nutrient levels in 10 streams in a historically agricultural region of the Virginia Piedmont. Historical (1963) and contemporary (2011) impervious surface, open area, and forested cover were evaluated using aerial photos and GIS data. Macroinvertebrates were collected in the fall of 2012 and spring of 2013. Water quality parameters (temperature, conductivity, alkalinity, hardness, and DO) and nutrient concentrations (NH3+NH4, PO4-P, NO3-N, Cl, and SO4) were measured at each site. Overall, forest cover decreased by 6.29%, open area decreased by 1.46%, and impervious surface increased by 4.83% from 1963 to 2011. Macroinvertebrate communities were explored using Principal Coordinates Analysis and were found to be significantly related to 2011 percent impervious surface. Water quality parameters were not significantly related to contemporary or historical land cover. Nitrate was negatively related with 2011 forest cover and positively related with 2011 open area; chloride was positively related with 2011 impervious surface and negatively related with 2011 open area. For the 10 watersheds included in this study, contemporary land cover is a better predictor of macroinvertebrate assemblages and nutrient concentrations than historical land cover.Master of Science
25
Raunio, J. (Janne). "The use of Chironomid Pupal Exuvial Technique (CPET) in freshwater biomonitoring: applications for boreal rivers and lakes." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514286834.
Full textAbstract:
Abstract
In this thesis, I used the Chironomid Pupal Exuvial Technique (CPET) to detect anthropogenic impacts and to determine chironomid species composition in boreal rivers and lakes. The main objectives of the thesis research were i) to evaluate the importance of timing of sampling in the use of the CPET method (I, II), ii) to identify chironomid indicators of different environmental conditions (II, III, IV), and iii) to compare performance of the CPET method and more traditional sampling techniques in detecting anthropogenic impacts and chironomid species composition (III, V). I also determined emergence patterns of lotic chironomids in southern Finland (II, IV).
Timing of sampling was found to be a critical design factor in the application of the CPET, especially if the trophic gradient between study sites was short. Sampling occasions need to match with the emergence periods of indicator chironomid taxa to ensure the maximum likelyhood of detecting human impacts, if any exist. However, the optimal timing of sampling varies spatially and is dependend on several environmental factors, such as latitude, altitude and trophic gradient. The shift in taxonomic composition of emerging chironomids was found to be especially rapid in spring, and tended to decrease towards autumn. This was probably due to the short emergence periods of some spring-emerging univoltine species, with their annual emergence taking only a few weeks. In contrast to whole genera, the detection of a certain species may require accurate timing of sampling. Thus, among-site differences observed at species level may reflect spatially varying emergence patterns rather than true differences in community composition. On the other hand, because of the among-species variation in species' tolerances towards, for example eutrophication, genus level identification may mask subtle differences between study sites. Nevertheless, for most monitoring purposes genus level identification seems practical and adequate, although species level resolution is desirable.
Comparisons of the CPET method and more traditional grab sampling showed that pupal exuvial samples provided a more complete picture of the chironomid fauna, and that this information was obtained cost-effectively. Further, the integrative nature of the CPET was found to be critically important in the assessment of both lotic and lentic habitats. Sampling only a single macrohabitat type may result in biased estimates of the ecological condition of the whole water body. Further, in comparison to profundal grab samples, integrating species from various habitats using the CPET method appeared to have only a minor negative influence on the signal strength.
Determination of emergence patterns of lotic chironomids showed that nearly 200 chironomid species occurred frequently in rivers of southern Finland. A major proportion of species richness was accounted for the sub-families Chironominae (emerging mainly during the summer months) and Orthocladiinae (spring and autumn). Overall, these studies demonstrated that the CPET is a cost-effective and sensitive method for the assessment and monitoring of freshwaters, and should be considered as an alternative and/or supplementary tool to more traditional sampling methods.
26
Dahl, Joakim. "Detection of human-induced stress in streams : comparison of bioassessment approaches using macroinvertebrates /." Uppsala : Dept. of Environmental Assessment, Swedish Univ. of Agricultural Sciences, 2004. http://epsilon.slu.se/s332.pdf.
Full text
27
Ranganath, Sheila Casaba. "Recovery of Channel Morphology and Benthic Macroinvertebrate Assemblages after Livestock Exclusion." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33455.
Full textAbstract:
Measurements in paired stream reaches with and without livestock access in southwestern Virginia suggest that livestock exclusion practices installed on short, isolated stream reaches result in improved geomorphic and riparian vegetation condition, but do not significantly improve the benthic macroinvertebrate assemblage. Detailed longitudinal and cross-sectional surveys, pebble counts, and rapid geomorphic assessments were conducted on contiguous, paired stream reaches (5 pairs) with and without active livestock access across a range of time since livestock exclusion was implemented. In addition, bank characteristics were quantified by measuring groundcover biomass, shrub crown volume, tree density and diameter, soil bulk density, and particle-size analysis. Benthic macroinvertebrates were collected with a D-frame dip net and quantified using the Virginia Stream Condition Index (SCI), and other benthic macroinvertebrate metrics. We determined that: 1) small lengths of livestock exclusion can significantly increase channel depth and decrease the width to depth ratio, and increase groundcover vegetation growth, but do not significantly alter benthic macroinvertebrate assemblages; and, 2) qualitative geomorphic assessment results showed trends over time since exclusion (0 to greater than 50 years), but not in any of the other parameters evaluated. These observations suggest that a more targeted and holistic approach that addresses watershed-wide impacts must be implemented to restore aquatic habitat. (Key Words: CREP, stream channel morphology, livestock exclusion, agriculture, benthic macroinvertebrates, riparian buffers.)Master of Science
28
Hedrick, Lara B. "Evaluation of the impacts of highway construction on sediment and benthic macroinvertebrates in Appalachian streams." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5643.
Full textAbstract:
Thesis (Ph. D.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains xii, 162 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references.
29
Hilderbrand, Robert Howard. "Relations between large woody debris, physical habitat, and benthic macroinvertebrates in Appalachian mountain streams." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06082009-170744/.
Full text
30
Longing, Scott Douglas. "Ecological studies of benthic macroinvertebrates for determining sedimentation impacts in Chattahoochee National Forest streams." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27008.
Full textAbstract:
Understanding sedimentation impacts to benthic macroinvertebrates in headwater, mountain streams is a top priority of watershed management programs in the Chattahoochee National Forest. Five studies involving the analysis of historical, biological survey data and current data were conducted to improve our understanding of macroinvertebrate response to sedimentation and to support the development of biological information for sediment load models to be applied in the Chattooga River watershed. An initial analysis of historical data involving a composited, macroinvertebrate reach-scale sample revealed weak relationships between assemblage metrics and sedimentation, which was similar to results of two recent macroinvertebrate studies that found biological ratings of good or excellent with reported physical impact attributed to sedimentation. Those findings and field reconnaissance in the Chattooga River watershed revealed that patchy, coarse sands may be the primary issue of concern regarding sedimentation impact to benthic macroinvertebrates. Therefore, a modified sampling approach was used to investigate relationships of macroinvertebrates and environmental conditions that included micro-habitat patches containing coarse sands, a product of erosion associated with Southern Blue Ridge, silicate parent geology. At the microhabitat, patch scale, flow velocity was the main environmental factor associated with a macroinvertebrate assemblage gradient, and was significantly correlated with percent deposited sediment across 264 samples. The high dominance of just a few macroinvertebrate genera, and the majority lack of individual macroinvertebrate associations with dominant substrate types may suggest that the dominant macroinvertebrates utilize a multi-microhabitat portion of the streambed at any given time, which may be due to the homogenization of streambeds due to sand (providing ease of movement) and its immobility (low bedload volume and sand patch shift). Because flow was the only significantly correlated environmental variable on an assemblage gradient produced by ordination (and was individually correlated with dominant substrate and percent deposited sediment), a subsequent study was conducted to determine macroinvertebrate sensitivity to deposited sediments among two flow-differentiated habitat types. Results showed that more taxa were related to a gradient of percent deposited sediment in fast water habitats, and no taxa were positively correlated with percent deposited sediment. Indicator species analysis found a number of taxa that were associated with a four-level grouping of percent deposited sediment levels. Therefore, a final study involved calculating deposited sediment tolerance values using indicator species associations and individual cumulative abundances across percent deposited sediment levels. The final index developed from cumulative abundances showed a relationship with deposited sediment within the range 0 â 30%, and that low range was due to the low deposited sediment levels at which all 50% cumulative abundances fell (1 - 10%). The sedimentation index produced from indicator species analysis produced a reach-scale index that was related to percent pool embeddedness. Key findings from these studies are: (1) sand is the primary deposited sediment type, with most streambed comprised of cobble-sand substrate, (2) few taxa are associated with deposited sand substrate, (3) there are high numbers of a relatively few dominant taxa across samples and streams, (4) macroinvertebrate response to deposited sediments is greatest in fast water habitats, and (5) the developed sedimentation biotic index is a potential, assemblage-level indicator of increasing sedimentation in these headwater systems. The functional and habit organization of the four most dominant taxa determined in recent studies suggest that they may be utilizing sand patches for crawling and collecting food, therefore structurally adapting to long-term, press disturbances due to historical and contemporary anthropogenic activities and natural erosion. In addition, macroinvertebrate assemblage composition in these streams indicates overall good â healthâ and suggests streambed stability in the presence of a large portion of coarse sand. However, an important question that remains involves sand movement along streambeds and the ecological consequences of continued sediment inputs to these headwater systems.Ph. D.
31
KORPIK, JEFFERY S. "IMPACT OF HABITAT AND WATER QUALITY ON THE BENTHIC MACROINVERTEBRATE COMMUNITY IN A MULTI-STRESSED URBAN STREAM." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123858583.
Full text
32
Vasconcelos, Márlon de Castro. "Efeito do sedimento fino de origem terrestre sobre a fauna de macroinvertebrados bentônicos em riachos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/10908.
Full textAbstract:
O aporte de sedimento fino é um dos principais agentes causadores de impactos a ecossistemas aquáticos. Este trabalho teve por finalidade avaliar por experimentalmente o efeito do sedimento fino sobre a fauna de macroinvertebrados bentônicos em um riacho subtropical. O local escolhido foi o rio Forqueta no distrito de Barra do Ouro pertencente ao município de Maquiné, RS. Foi adicionado por tratamento cerca 3138 cm3 de sedimento fino, separado em duas frações: areia fina (0 mm a 0,250mm) e areia grossa (0,25 mm a 1mm), em dois níveis, com e sem sedimento. Os dados foram analisados através por meio de uma Análise de Variância (ANOVA) de dois fatores para abundância total, riqueza e riqueza rarefeita, além de uma Análise de Variância Multivariada (MANOVA) para abundância relativa e composição de espécies e de uma Análise de Correspondência Canônica (pCCA), esta última, para avaliar o quanto eventos de perturbações influenciam a fauna aquática. A interação entre a velocidade do fluxo e os fatores envolvendo sedimentos também foram avaliados. O sedimento fino afetou negativamente a abundância total, a riqueza e a composição de espécies, mas não a riqueza rarefeita e a abundância relativa.O fluxo foi um importante fator para a distribuição da fauna avaliada, sendo a abundância, riqueza e a riqueza rarefeita maior em áreas com maior fluxo. Houve interação do fluxo com a areia fina, aumentando seu efeito sobre a abundância total e riqueza rarefeita em locais com maior velocidade de fluxo. A pCCA mostrou que eventos pontuais e de curta duração de acréscimo de sedimento fino não são danosos à fauna aquática. Os resultados obtidos mostram que o sedimento fino afeta de forma negativa a fauna de macroinvertebrados bentônicos em riachos, e este efeito negativo se dá por diversas formas, tais como redução do hábitat, perda da qualidade do alimento, estresse fisiológico e por outros. A relação da fauna com a velocidade pode ser atribuída às preferênciasecológicas dos grupos encontrados. Por alguns resultados divergirem de estudos prévios, o efeito do sedimento fino sobre a fauna aquática deve ser mais bem estudado.One of the main forms by which aquatic ecosystems are impacted is the input of fine sediment. The objective of our study was to determinate by one experiment the effect of fine sediment on benthic macroinvertebrates in subtropical streams. The study area was the Forqueta River in Barra do Ouro district of Maquiné city, Rio Grande do Sul, Brazil. It’s was added 3138 cm3 of sediment, in two fractions: fine sand (0mm – 0.25mm) and coarse sand (0.25mm – 1mm) into the river with two levels (with or without sediment) . The data were analyzed by Analysis of Variance (ANOVA two-way) for abundance, richness and rarefied richness, the last one intended to compare species richness based on an equivalent number of individuals. Using Multivaried Analysis of Variance (MANOVA) we examined the effect of fine sediment on relative abundance and composition of species. Sediment was used as one factor in four levels. A Partial Canonical Correspondence Analysis (pCCA) was used to examine the effect of the disturbance event on communities. The interaction between the flow and the factors of the sediment was examined. There was a negative effect of fine sediment on abundance, richness and species composition, but the effect was null on relative abundance and rarefaction of species richness. The flow was important for distribution of individuals colleted. The abundance, species richness and rarefied richness were highest on places with fastest flows. The flow increased the effect of fine sand on abundance and rarefied richness. The pCCA showed that disturbance events of small frequency consisting of input of terrestrial sediment have no negative effects on benthic macroinvertebrate. The relationship between flow and benthic macroinvertebrates can be attributed to the ecological preferences of species. These results showed that fine sediment impact is harmful for benthic macroinvertebrates in streams, particularly in termsof abundance. This negative effect may be a consequence of loss of habitat, reduced food quality, physiological stress and others forms. Because some results differ from other studies, the effect of the fine sediment on the benthic macroinvertebrates needs to be better studied.
33
Jarving, Ohlsson Julius, and Linus Welander. "Hasslebäcken En studie av vattenkvalitet,vandringshinder och potentiellareproduktionsbiotoper för öring." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-32374.
Full textAbstract:
This paper is about analyzing water quality of a stream that flows in southwest of Swedencalled Hasslebäcken. The stream is a tributary of Suseån and has its springs in the naturereserve Biskopstorp and flows through a mixed landscape of mostly spruce forests andagriculture land. Little is known about Hasslebäcken and its water and therefore a study by request of Suseåns vattenråd was performed. The study consisted of analyzing the water ofphosphorous, nitrogen, pH, suspended particles and conductivity. To broaden the examination of water quality sampling of benthic macroinvertebrates and two index (ASPTindex and Shannon’s diversity index) of water quality were used. Another part of the study were to search for fish barrier in the stream and to evaluate the possibilities for troutspawning and habitats. The whole stretch of the stream were examined and eleven differentsampling sites were used. The results show that Hasslebäckens upper parts have low levelsof nutrients while the lower parts show intermediate to extremely high levels. The indexresults points at low ecological values for Shannon and high ecological values for ASPT. Thisis normal for a stream that flows through an agricultural landscape. The results concerning pH show a lower pH in the upper parts than in the lower parts. This is also normal for a stream in a production forest of spruce in these parts of Sweden. Hasslebäcken also have several fish barrier that prevent various fish species to migrate up along the stream from thesea. The evaluation of trout habitats and spawning area show decent possibilities for successful reproduction and growth.
34
Braccia, Amy. "Quantifying the environmental factors that determine benthic macroinvertebrate assemblages in streams by analyzing stressors associated with a gradient of cattle grazing." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29326.
Full textAbstract:
Relationships between macroinvertebrate assemblages and environmental stressors were assessed from fall 2002 through spring 2004 in five small streams that represented a study design that involved a gradient of increasing stress (increased cattle density). Macroinvertebrate assemblages were related to environmental factors that were quantified at the sample scale. Environmental factors and macroinvertebrates were concurrently collected so that assemblage structure could be directly related to environmental variables and so that the relative importance of stressors associated with cattle grazing in structuring assemblages could be assessed. Macroinvertebrate metrics showed significant and strong responses to cattle density during most sampling periods. The majority of metrics responded negatively to the grazing gradient, while a few (total taxa richness, number of sensitive taxa, and % collector filterers) increased along the gradient before declining at the most heavily grazed sites. Total number of sensitive taxa and % Coleoptera had the strongest relationship with cattle density throughout the study period. Based on sample-scale, quantitative measures of environmental variables, measures of physical habitat (% fines and substrate homogeneity) were most important in structuring assemblages. Detrital food variables (coarse benthic and fine benthic organic matter) were secondarily important while autochthonous food variables (chlorophyll a and epilithic biomass) were not as important in influencing assemblage structure. Based on a comparative analysis of reach-scale habitat measures and estimates, quantitative measures of % fines, collected from within an enclosed sampler concurrently with macroinvertebrates, were the best predictor of macroinvertebrate assemblages. Quantitative measures and visual estimates of riparian and channel characteristics had strong relationships with macroinvertebrate metrics but the relationships were never as strong as those detected with instream measurements of % fines. The channel characteristic, bank height, was the best predictor of % fines.Ph. D.
35
Merricks, Timothy Chad. "Ecotoxicological Evaluation of Hollow Fill Drainages in Low Order Streams in the Appalachian Mountains of Virginia and West Virginia." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/32977.
Full textAbstract:
Hollow fills are composed of excess spoil and debris produced from surface coal mining that is not returned to the original mined site. Hollow fills are often constructed in the head of hollows nearby or adjacent to the mined land area, which may be the origins of headwater streams or drain into low order systems. Eleven hollow fills were utilized in evaluating the influence fill drainages had on low order streams in Virginia and West Virginia. The study was conducted in six watersheds including; Five Mile Creek in Mingo County, West Virginia, Trace Fork in Mingo County, West Virginia, Lavender Fork in Boone County, West Virginia, Middle Creek in Tazewell County, Virginia, South Fork of the Pound River in Wise County, Virginia, and Powell River in Wise County, Virginia. Bioassessment procedures used in the evaluation of hollow fill drainages included water/sediment chemistry, acute water column toxicity testing using Ceriodaphnia dubia, chronic sediment toxicity testing using Daphnia magna, benthic macroinvertebrate surveys, and in situ Asian clam (Corbicula fluminea) toxicity testing. Common significant differences in water quality between reference and fill influenced sites, among all watersheds, were elevated conductivity and water column metal concentrations, particularly aluminum and copper. Water column and sediment toxicity testing reported limited significant mortality or reproductive impairment associated with hollow fill drainages. The West Virginia watersheds used in the study consisted of headwater streams originating directly from the settling ponds, placed at the base of the hollow fills, receiving drainages from the fills. Benthic macroinvertebrate analysis reported no significant alteration in total taxa or EPT richness downstream of the ponds. Yet, collector filterer populations, including benthic macroinvertebrates and in situ Asian clams, were enhanced directly downstream of the ponds due to organic enrichment originating from the ponds. A decrease in collector filterer populations and lowered clam growth suggested the organic enrichment dissipated downstream from the ponds. Chlorophyll a analysis of the phytoplankton community was not significantly related to the enhance collector filterer populations in the streams, however the high concentrations in the settling ponds suggest abundant algal communities. The hollow fills evaluated in Virginia drained into receiving systems, whose headwater origins were not directly related to hollow fill drainages. Low taxa richness was associated with the hollow fill and settling pond drainages, however receiving system sites were minimally influenced. Yet, as reported in the West Virginia watersheds, the settling ponds input organic enrichment that enhanced collector filterer populations, including benthic macroinvertebrates and in situ test clams. An analysis of the hollow fillsâ age, or maturity, reported no significant difference between young and old fills. In general, a common feature of among the various aged fill drainages was elevated conductivity, compared to reference sites of the watersheds.Master of Science
36
Soucek, David John. "Integrative Bioassessment of Acid Mine Drainage Impacts on the Upper Powell River Watershed, Southwestern Virginia." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/27852.
Full textAbstract:
Acid mine drainage (AMD), a result of oxidation of minerals containing reduced forms of sulfur (pyrites, sulfides) upon exposure to water and oxygen, is an environmental problem associated with abandoned mined lands (AML). Numerous studies have documented the impacts of AMD upon aquatic communities within acidified stream reaches; these impacts include reduced taxonomic richness and abundance, and/or a shift from pollution sensitive to pollution tolerant species. This dissertation comprises a number of integrative assessments and experiments conducted to investigate the nature of AMD ecotoxicity in the upper Powell River watershed. Emphasis was placed upon bioassessment methodologies and AMD impacts beyond the zone of pH depression. Major findings and processes developed included: 1) an Ecotoxicological Rating (ETR) system was developed that integrates chemical, toxicological, and ecological data into a single value depicting the relative environmental integrity of a given station within a watershed; 2) water column chemistry rather than sediment toxicity was the major factor causing acute toxicity to aquatic biota in close proximity to AMD discharges; 3) solid ferric hydroxide can cause acute toxicity to standard test organisms in the absence of dissolved iron; 4) Asian clams (Corbicula fluminea) can be used to detect both acutely toxic AMD inputs and nutrient loading in low order streams, and clam responses of survival and growth reflect those of indigenous communities to the two contaminant types; 5) aluminum (Al) in transition from acidic to neutral pH waters can cause acute toxicity to aquatic invertebrates, and may be the cause of impaired benthic macroinvertebrate communities in neutral pH (>7.0) waters downstream of an acidic tributary; 6) in the larger river system (North Fork Powell and Powell mainstem), urban inputs appear to have a greater influence upon aquatic communities than metal loading from AMD impacted tributaries; 7) the use of individual level assessment endpoints, such as Asian clam growth in in situ toxicity tests, eliminates variables that may confound attribution of community level impacts to contaminants; and 8) the near elimination of predatory stoneflies (Plecoptera) downstream of the Stone/Straight Creek tributary to the North Fork Powell River was associated with water column Al concentrations.
This research was funded by the Virginia Department of Mines, Minerals, and Energy, Division of Mined Land Reclamation, and by the Powell River Project.Ph. D.
37
Layton, Raymond Jay. "Production of benthic macroinvertebrates in a river used for commercial navigation : Kanawha River, West Virginia /." Thesis, This resource online, 1985. http://scholar.lib.vt.edu/theses/available/etd-03032009-041041/.
Full text
38
Horne, Jennifer L. "The influence of grazing macroinvertebrates on the structure of benthic diatom assemblages : implications for biomonitoring." Thesis, University of Sheffield, 2009. http://etheses.whiterose.ac.uk/586/.
Full text
39
Bernard, Aaron Michael. "Geospatial Modeling of Forest Road Networks and Their Effect on Stream Macroinvertebrate Communities." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/33338.
Full textAbstract:
Road construction and maintenance throughout the country continues to be one of the largest contributors of sediment pollution to aquatic systems. Though impacts of road networks on aquatic systems can be potentially severe, little work has been performed to evaluate the effect that road spatial location within a watershed has on water quality. To address this issue from a quantitative perspective, a â Road Impact Factorâ protocol was designed to identify potential erosion-prone segments of road networks based on road gradient, spatial location based on hydrologic flow length, surface composition, and water control installations. The protocol was developed for two regions in Central Idaho and Eastern Oregon. We then used the hydrologic travel time procedure, developed for use in the Hydrologic Engineering Center Hydrologic Modeling System (HEC-HMS) runoff and routing model, in order to characterize the spatial distribution of potential road runoff impacts within the study areas. Ten macroinvertebrate metrics sensitive to sedimentation (i.e. % Intolerant Taxa, Hilsenhoff Biotic Index, etc.) were analyzed to test the significance of the spatial distribution of Road Impact Factors. These 10 metrics were analyzed under the hypothesis that values will be lower for those study areas that have a higher degree of road impact and a lower distance between the road segments and stream reaches. Results of a quadrant analysis and hierarchical clustering analysis showed hypothesized trends for several metrics in Idaho, though the trends were not strong. No trends were observed in Oregon. The variability in results is likely due to limitations of the input datasets.Master of Science
40
Bopp, Jesse A. "Combined effects of water chemistry, canopy cover, and stream size on benthic macroinvertebrates along a central Appalachian stream continuum." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2474.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains viii, 96 p. : ill., maps (some col.). Includes abstract. Includes bibliographical references (p. 41-51).
41
Sokol, Eric Robert. "Community ecology of aquatic insects in forested headwater streams in the southern Appalachians." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/29110.
Full textAbstract:
Competing paradigms of community assembly emphasize different mechanisms for predicting patterns in biogeography. Niche assembly emphasizes the role of environmental gradients as filters that organize a metacommunity by locally selecting colonizers with similar functional traits, whereas dispersal assembly emphasizes the importance of source pool characteristics and dispersal limitation in organizing a metacommunity. In this study, I developed a framework that uses spatially explicit patterns in taxonomic and functional measures of community composition as diagnostics for community assembly 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 used as null models to assess which functional traits were the best candidates to explain how community composition was influenced by environmental gradients: an assessment of niche-based community assembly. Regional scale patterns suggested that niche-based community assembly was the dominant mechanism organizing community composition in headwater streams at local scales (<30km). Therefore, I compared how well trait-neutral models identified functional traits as relevant to community sorting against how well observed trait distributions correlated with environmental variation at a local scale, in the Ray Branch catchment (<10km study extent). Functional traits exhibiting non-random distributions within the Ray Branch watershed were most strongly correlated with environmental variation. Lastly, I assessed how the influences of niche and dispersal assembly on benthic macroinvertebrate community composition were affected by disturbance (shelterwood logging). Environmental variables defining the habitat template, and macroinvertebrate community composition, were measured before and after the disturbance; and path analysis was used to quantify the disturbance effect. The relationship between environmental variation and functional composition increased following logging, indicating disturbance augmented the influence of environmental filters, and consequently, the importance of niche-based community assembly. My dissertation provides the framework for a novel assessment of taxonomic and functional community composition data to infer the types of ecological dynamics that organize communities in the landscape. Additionally, this work provides a theoretical basis for assessing how dominant ecological processes change, in predictable ways, in response to changes in the habitat template.Ph. D.
42
Ilmonen, J. (Jari). "Benthic macroinvertebrate and bryophyte assemblages in boreal springs: diversity, spatial patterns and conservation." Doctoral thesis, University of Oulu, 2009. http://urn.fi/urn:isbn:9789514290633.
Full textAbstract:
Abstract
In this thesis, I studied the patterns in the assemblage composition as well as the biogeography and ecology of spring macroinvertebrates and bryophytes in Finland. My main objectives were to assess the importance environmental variables to macroinvertebrate and bryophyte assemblage composition in springs at the level of multiple spatial scales. In addition, I assessed the importance of springs in the boreal mire landscape, and sought the ecological and environmental determinants of a key species in boreal springs. In a large-scale study, I also examined the concordance between macroinvertebrates and bryophytes across boreal ecoregions, and assessed how macroinvertebrate assemblage variation corresponds to terrestrially-based ecoregions.
Locally, spring macroinvertebrate assemblage structure displays high variation between different kinds of mesohabitats within springs, highlighting the importance of careful sampling of all habitat types in spring surveys. Helocrenes and other aquatic-terrestrial ecotone habitats harbour the highest species diversity and most spring-dependent species among spring habitat types. Further, spring-influenced mire patches were shown to have distinct cranefly assemblages in the mire landscape and to harbour higher cranefly diversity than mire types with lower trophic status, emphasising the importance of springs for mire biodiversity. Regionally, a red-listed spring-dependent caddisfly species appeared to be a surrogate for a high spring conservation value, indicating high overall species diversity and the occurrence of additional red-listed species.
On a large geographical scale, intersecting the boreal ecoregions, a pattern of gradual change of benthic macroinvertebrate assemblage composition from south to north was detected, largely corresponding to terrestrially-derived ecoregions. However, the physical attributes of springs also need to be taken into account in bioassessment studies. Macroinvertebrate assemblage variation also correlated with physical habitat-scale variables, but not with changes in water chemistry. In contrast, spring bryophyte assemblages showed a distinct response to variation in water chemistry, but not to variation in physical habitat characteristics. Bryophytes and insect assemblages were concordant with each other on the large geographical scale, although the concordance was rather weak. Because of their different kind of responses to the physical and chemical variables, insects and bryophytes of springs are poor surrogates for each other in boreal springs.
43
Willey, Katherine Tara. "Environmental Factors Determining the Pre-Restoration Benthic Macroinvertebrate Assemblage In A Stream Used By Cattle." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35221.
Full textAbstract:
I investigated the baseline benthic macroinvertebrate community in relation to the environmental conditions in a section of Smith Creek, north of Harrisonburg, VA, prior to restoration. Quantitative benthic macroinvertebrate and environmental samples were collected in April and September 2006 from the Bruce Farm (BR) section of Smith Creek and the nearby Mixed Use (MU) section of Mountain Run. BR had been heavily used for cattle grazing for decades and suffered from sediment, nutrients, and lack of a forested riparian zone. MU had a forested riparian zone, but still received nutrient and sediment inputs from upstream cattle grazing. Visual habitat assessments were performed in September 2006 and were compared to quantitative measures. Benthic macroinvertebrate densities and taxa richness were greater at BR (total density for combined seasons = 52,438; taxa richness for both seasons = 84) than MU (total density for combined seasons = 3,982 and taxa richness for both seasons = 63). Biological environmental variables related to nutrients and growth of plants on rocks (ash-free dry mass, chlorophyll a, epilithic biomass) influenced the benthic macroinvertebrate assemblage more than physical environmental variables related to the substrate composition (% fines, % gravel, Traskâ s sorting coefficient). Visual habitat estimates were not as effective as quantitative measures of habitat for explaining the benthic macroinvertebrate assemblage.Master of Science
44
Tiller, David, and n/a. "The impact of sewage effluent on the benthic macroinvertebrate community of the upper Thredbo River." University of Canberra. Applied Science, 1988. http://erl.canberra.edu.au./public/adt-AUC20061109.145223.
Full textAbstract:
Thredbo Village is a year round alpine resort located in Kosciusko
National Park, south eastern New South Wales. Treated sewage effluent
from Thredbo Village is discharged to the upper Thredbo River. The
river is a rocky bottomed, high mountain stream (> 1,200 m altitude in
the study area) flowing predominantly through subalpine woodland, the
only major impact on the river within the study area was that of the
Thredbo Village alpine ski resort.
Nutrient concentrations were measured in the upper Thredbo River
monthly from January to September 1983 at 9 sites along the river, both
upstream and downstream of the effluent discharge. In addition,
invertebrates were collected at the same sites in January, April and July
1983.
The near pristine section of the upper Thredbo River upstream of
Thredbo Village was low in phosphorus and nitrogen (<20 mg m-3 and
<100 mg m-3 respectively). The sewage effluent discharge was high in
phosphorus and nitrogen (up to 5,000 mg m-3 and 28,000 mg m-3
respectively). Phosphorus generally returned to concentrations similar to
those measured in the pristine sections by 3.5 kilometres downstream of
the discharge. Nitrogen (mostly in the form of nitrate and nitrite)
often remained elevated down to the most downstream site, 8 kilometres
downstream of the effluent discharge.
The elevated nutrient concentrations immediately downstream of the
effluent discharge stimulated the growth of attached filamentous algae in
January when conditions for growth were most favourable. It is
concluded that this growth provided an additional food source for several
invertebrate taxa, Cricolopus sp. 12E and 160E (Diptera, Chironomidae),
Conoesucidae sp. TR6, Oxyethira columba (Trichoptera), Nais sp.,
Aeolosomatus niveum (Oligochaeta), and Austrocercella tillyardi
(Plecoptera), which occurred in higher numbers downstream of the effluent
discharge. Downstream of the effluent discharge the taxonomic
composition of the invertebrate community was not altered substantially
from that upstream, although there was a significant increase in the
abundance of the taxa which could take advantage of the increased food
resource. The changes in the invertebrate community were not evident
3.5 kilometres downstream of the effluent discharge, which corresponded
to the return of phosphorus concentrations to background levels. There
were increased abundances of several invertebrate taxa downstream of
both Thredbo Village and the rubbish tip in January which were
consistent with, but not as great as, those downstream of the sewage
effluent discharge. This was likely to be a result of increased nutrient
loads from urban runoff and tip leachate at these sites which possibly
lead to increased algal productivity. However, nutrient concentrations at
these sites were not notably higher than at the control site. The
sewage effluent discharge resulted in only small changes to the
invertebrate community in April or July 1983.
45
Nebra, Costas Alfonso. "Ecology and bioindicator potential of benthic macroinvertebrates in a Mediterranean salt wedge estuary: the Ebro River case." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/385277.
Full textAbstract:
The Ebro Delta-Estuary complex is one of the largest wetland areas in the western Mediterranean, and it is considered one of the most important estuarine zones in Europe. In 2013, the Ebro watershed, including its deltaic plain, was declared World Biosphere Reserve by the UNESCO. Due to its singularity, a total of 7.736 ha of Delta are protected under the Spanish Natural Park figure (including coastal lagoons, freshwater springs, bays and adjacent coastline) which stands out by its faunal (mainly, ornithological and ichthyological) and halophilic floral composition. The Ebro River flows into the Mediterranean Sea and forms a salt wedge or highly stratified estuary, a unique estuary type only found in microtidal coasts worldwide. Diverse human activities occur in this area such as tourism, shooting, commercial fishing and agriculture, as a consequence the entire Delta-Estuary complex is under permanent anthropogenic pressures threatening its ecological integrity; therefore, its conservation should be a priority task.
The main objective of the present PhD thesis was to analyze the ecology of the benthic macroinvertebrate community from the Ebro Estuary, in order to evaluate its potential use as biological indicator of highly stratified Mediterranean estuaries. To achieve this goal the study of the macroinvertebrate community was carried out at a high level of taxonomic resolution and its spatiotemporal dynamics in relation with the estuarine environmental gradients was assessed. An exhaustive environmental description of benthic condition of the Ebro Estuary was done, including water physico-chemistry, grain size characterization and total organic estimation in sediments. Furthermore, due to the relevance of river discharge on salt wedge dynamics and therefore on estuarine benthic ecology, a comparison between current salt wedge dynamics and past near natural conditions was done using historical data available at the Ebro basin authority database. Finally, the bioindicator potential of macroinvertebrates to assess the ES according to the WFD criteria was examined throughout the analysis of the response of macrozoobenthos based metrics to the main human pressures in the Ebro estuary, nutrient enrichment and altered flow regime.El objetivo general de la presente tesis fue describir la ecología de la comunidad de macroinvertebrados bentónicos del estuario del Río Ebro, un estuario de cuña salina o altamente estratificado. En concreto esta tesis exploró a un alto nivel de resolución taxonómica la dinámica espacio-temporal de la comunidad de macroinvertebrados en relación con los gradientes ambientales de un estuario de este tipo, con el propósito de evaluar su uso potencial como indicadores biológicos en otros estuarios mediterráneos altamente estratificados. La condición bentónica actual del estuario del río Ebro fue descrita de manera exhaustiva, incluyendo la caracterización físico-química del agua (concentración de nutrientes, contenido de sólidos en suspensión, oxígeno disuelto, pH, temperatura y salinidad) así como un análisis granulométrico del sedimento y la estimación del contenido en materia orgánica. Los datos físico-químicos fueron utilizados para la estimación de un gradiente de contaminación orgánica mediante la técnica de PCA. Además, debido a la relevancia del caudal del río en la dinámica de la cuña salina (avance, retirada y permanencia) y por lo tanto en la ecología bentónica del estuario, se comparó la dinámica actual de la cuña salina, gravemente alterada por la regulación del caudal, con la dinámica natural de la cuña salina que se obtuvo a partir de datos históricos disponibles en la página web de la Confederación Hidrológica del Ebro. Finalmente, el potencial bioindicador de los macroinvertebrados, con el fin de determinar el Estado Ecológico de acuerdo con los criterios de la DMA, fue evaluado mediante el análisis de la respuesta de varios índices bióticos basados en macroinvertebrados en relación con las principales presiones antrópicas que afectan al estuario del Ebro, contaminación orgánica y la alteración hidrológica. Los resultados obtenidos evidencian la relevancia de los macroinvertebrados en el funcionamiento ecológico del estuario así como su idoneidad como indicadores biológicos en relación con la contaminación orgánica Las principales conclusiones obtenidas en esta tesis son: 1. La comunidad actual de macroinvertebrados del estuario del Ebro difiere en gran medida a la encontrada en la década de los 90 cuando la condición de anoxia, debida a un exceso de materia orgánica de origen eutrófico, impedían el establecimiento de comunidades biológicas. La comunidad actual de macroinvertebrados mostró valores excepcionalmente altos de riqueza (213 taxones) comparado con otros estuarios templados; los moluscos, poliquetos y crustáceos fueron los grupos dominantes en términos de riqueza y de abundancia. 2. Como consecuencia de la regulación hidrológica a la que está sometido el tramo bajo del río Ebro, la dinámica de la cuña salina está gravemente alterada causando largos períodos de presencia de cuña salina y de estratificación de la columna de agua. La presencia de cuña salina divide al estuario del Ebro en dos tramos opuestos en función de sus características limnológicas; aguas arriba de la cuña, un tramo con características fluviales y una comunidad de macroinvertebrados dulceacuícola (alto estuario) y aguas abajo un tramo estuarino con agua con salinidades prácticamente marinas debido a la escasa mezcla con el agua del río y una comunidad de macroinvertebrados de origen marino (bajo estuario). 3. El cambio brusco de salinidad fue el principal factor que determinó la estructura de la comunidad de macroinvertebrados del estuario del Ebro. Debido a la práctica inexistencia de agentes de mezcla entre la capa de agua dulce y la marina, el intercambio de materiales y de organismos es muy limitado, como consecuencia la distribución de la comunidad a lo largo del estuario encaja con un patrón de turnover o sustitución total. Este patrón junto con las características homogéneas de ambos ambientes (alto y bajo estuario) sugieren que el estuario del Ebro está funcionando en términos de fronteras ecológicas como un ecotono. 4. La estaciones de muestreo cercanas al punto nulo o nodal (punto donde contactan ambas capas de agua y con valores de velocidad cercanos a cero) mostraron los valores más bajos de riqueza y abundancia debido a que esta zona de mayor estrés dentro del estuario. 5. Durante la última década el estado químico del estuario del Ebro ha mejorado debido a la disminución de los aportes de nutrientes, en especial de fósforo, en toda la cuenca. Esto llevó a la mitigación del proceso de eutrofización y a una oligotrofización del estuario que actualmente recibe menos aportes de materia orgánica atenuando su impacto y reduciendo los eventos de anoxia e hipoxia. Como resultado de esta mejora, la comunidad de macroinvertebrados ha sido capaz de recolonizar el estuario alcanzando un alto grado de complejidad. 6. La comunidad de macroinvertebrados demostró su capacidad de respuesta frente a las principales presiones que afectan al estuario del Ebro. Los parámetros de la comunidad disminuyeron hacía el punto nodal en respuesta al incremento de factores de estrés hidrológico y al incremento de la contaminación en el punto nodal debido a la circulación convergente. 7. La alteración hidrológica de la dinámica de la cuña salina creó una estabilidad artificial en las condiciones ambientales, este hecho favoreció a la comunidad de macroinvertebrados. Como consecuencia tras la aplicación de varios índices biológicos se identificó una respuesta paradójica a esta presión, a mayor grado de alteración hidrológica mayor complejidad en la comunidad y por lo tanto mejor estado ecológico. Este resultado evidencia que es necesaria una aproximación diferente para la determinación del estado ecológico en cuencas mediterráneas donde los aspectos hidrológicos están ganando en relevancia en comparación con la calidad del agua y del sedimento.
46
Haidekker, Alexandra. "The effect of water temperature regime on benthic macroinvertebrates a contribution to the ecological assessment of rivers /." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976540819.
Full text
47
Mulders, Joseph Alexander. "Effects of land-use change on benthic macroinvertebrates in the upper reaches of the Apies-Pienaar catchment." Diss., University of Pretoria, 2015. http://hdl.handle.net/2263/53534.
Full textAbstract:
Urbanisation of catchment areas is a major cause of freshwater ecosystem degradation worldwide. As catchments become more developed and river ecosystems become increasingly engulfed in various land use activities, there is a growing need to understand these impacts on freshwater ecosystems. Benthic macroinvertebrates are extensively used as indicators of ecosystem health and have been an instrumental tool in ecosystem monitoring and management. The effects of changing land use on macroinvertebrates at a fine scale however, have not been extensively investigated.
Therefore an investigation was conducted to compare chemical, physical and biological surface water quality parameters and aquatic macroinvertebrate community composition along the first 8 km of the Hartbeesspruit, which contains multiple land use types, in the upper Apies-Pienaar catchment in Gauteng, South Africa.
Five sampling sites corresponding to changes in land use were sampled four times at six-week intervals from September 2013 to February 2014. Influential variables that were recorded included in-stream habitat, riparian cover, flow regime and surface water quality parameters. Physical surface water parameters that were tested in situ included pH, salinity, total dissolved solutes, temperature, clarity and conductivity. Ex situ surface water parameters that were tested included physical parameters (alkalinity and turbidity), chemical parameters (major ions, metal ions and nutrients), and biological parameters (bacteria, coliforms and Escherichia coli). Macroinvertebrates were sampled using Hester-Dendy artificial samplers, which, following a 6 week exposure period, were sampled three times from November 2013 to February 2014. Macroinvertebrates were identified to family level and counted.
Macroinvertebrate community composition across sites was assessed through macroinvertebrate abundance, family richness, SASS score, ASPT, Shannon-Wiener index, Pielou s evenness, non-metric multidimensional scaling and Indval analyses. Nineteen families were collected, of which only three made up 80% of macroinvertebrates sampled. These families were Hirudinea, Chironomidae and Oligochaeta.
Indices of macroinvertebrate community composition indicated a general increase in value from upstream to downstream which showed similar comparative variation between sites to physical water quality parameters (except temperature and clarity), major ions (except arsenic), the metal ion magnesium and nutrient sulphate. Surface water parameters showed patterns indicative of effects due to evaporation, dilution and connectivity of water flow along the stream due to the presence of dams and wetlands. Temperature was an important influence on macroinvertebrate abundance and family richness at a temporal scale.
On a spatial scale the most influential parameters on macroinvertebrate composition were seen to be depth, turbidity and conductivity, and temperature to a lesser extent. The land use types that showed the greatest association with various assemblages were the urban, recreational and least transformed wetland land uses. Although major influential factors, this pattern was not seen to be strictly due to the input of contaminants arising from associated activities, nor the variation in physical characteristics, but rather the discontinuity in flow regime.
It was concluded that at a fine scale, the strongest factors that influenced macroinvertebrate community composition along the Hartbeesspruit, was not land use type but rather the hydrological pathways of connectivity and stream flow that exist within the system. The hydrological pathways influenced values and concentrations of chemical and physical surface water parameters which in turn further influenced macroinvertebrate assemblages present.Mini Dissertation (MSc)--University of Pretoria, 2015.
Geography, Geoinformatics and Meteorology
MSc
Unrestricted
48
Evans, Shane Kent. "Studies of Benthic Macroinvertebrates in Western Virginia Streams as Related to the Implementation of Rapid Bioassessment Techniques." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30700.
Full textAbstract:
This study tested two key assumptions in developing regional biocriteria: (1) the accuracy of the ecoregion classification framework and (2) the accuracy of standardized qualitative sampling. Except for the Central Appalachians ecoregion, there was little or no correspondence of benthic macroinvertebrate distribution with the ecoregions or subregions of western Virginia. I found that it was more accurate to rearrange the subregions into three larger regions called bioregions: the forested hills and mountains (subregion 69a), valleys and plateaus (subregions 66c, 67a, and 67b), and the mountains (subregions 66a, 66b, 67c, and 67d). As an alternative to the ecoregion classification scheme, I classified my reference sites in biotic groups and then assessed the effect of several environmental variables on discriminating between the groups. There was a 69.8% correct classification rate using 14 environmental variables. Stepwise multiple discriminant analysis and graphical analysis showed that sampling date, slope, pH, habitat assessment score and distance to source were the best predictors of community structure. These environmental variables correctly classified 52.8% of the reference sites. These classification rates are comparable to rates published in similar studies. My study demonstrated that aggregations of subregions into bioregions and a biotic approach are more accurate classification schemes than ecoregions or subregions for biocriteria based on benthic macroinvertebrates.
A second study evaluated the accuracy of a standardized qualitative sampling approach, commonly used in rapid bioassessments, in assessing the biological condition of lotic systems. I compared a typical standardized qualitative sampling method with subsampling with a typical quantitative sampling method on a stream with varying degrees of impairment. Although some metrics did respond to differences in sample abundance, overall the two methods made similar estimates of community composition. The two sampling methods made the same assessment an average 89% of the time using multimetric index developed for the Mid-Atlantic Region. I found no pattern showing one method was more accurate in making assessments of biological condition than the other. Given the greater time and costs associated with quantitative sampling methods, I conclude that standardized qualitative methods, are preferable for rapid bioassessment approaches to environmental assessment.Ph. D.
49
Schmidt, Travis Scott. "Development and Implementation of Integrative Bioassessment Techniques to Delineate Small Order Acid Mine Drainage Impacted Streams of the North Fork Powell River, Southwestern Virginia." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/35095.
Full textAbstract:
Acid mine drainage (AMD) results from the oxidation of pyretic mineralogy, exposed by
mining operations to oxygen and water. This reaction produces sulfuric acid and
liberates heavy metals from the surrounding mineralogy and impairs water quality and
freshwater communities. The U.S. Army Corps of Engineers has begun an ecosystem
restoration project to remediate the abandoned mine land (AML) impacts to the North
Fork Powell River (NFP) and is utilizing the ecotoxicological rating (ETR) system to
delineate these affects to focus restoration efforts. The ETR was developed to summarize
the integrative data into a single number ranging from 0 to 100, which is descriptive of
the environmental integrity of a sampling station. The ETR is conceptualized to work as
an academic grading scale (0 through 100), rating reference stations with A's (90-100)
and B's (80-89) and impacted stations with C's (70-80), D's (60-70) and failures (F =
60). Two rounds of ETR investigations have evaluated seven headwater tributaries to
the NFP including investigations of Ely and Puckett's Creek from 1997 and 1998. This
thesis contains the results of the second series of ETR investigations at 41 stations in Cox
Creek, Jone's Creek, Reed's Creek, Summers Fork, Straight Creek, and areas in the NFP.
Eight stations were recommended for reclamation; CC 03, JCRF2 02, JCRF2 01, RCPS
09B, RCPS 11B, SULF 01, SU 02, and SU 01. Summers Fork was the most severely
impacted watershed of the second round of ETR investigations. An effort to streamline
the ETR to the most ecologically predictive parameters was successful in creating a
system more time and cost efficient then the initial ETRs and exclusive of benthic
macroinvertebrate surveys. The Modified ETR streamlined the ETR to just 5 parameters
including; mean conductivity, mean Asian clam survival, mean aluminum (Al) and
manganese (Mn) in the water column, and mean habitat score to describe the AMD
impacts to small headwater streams. Also, an investigation was conducted to determine
the mode of toxicity, (i.e., exposures to metal contaminated surface waters or sediments)
by which Al and iron (Fe) dominated AMD impairs benthic macroinvertebrate
communities. It was found that water column exposures both within and beyond the zone
of pH depression are the most likely mode by which AMD impairs the benthic
macroinvertebrate communities of the NFP.Master of Science
50
Hiner, Stephen W. "Analyses of Two Aspects of Study Design for Bioassessment With Benthic Macroinvertebrates: Single Versus Multiple Habitat Sampling and Taxonomic Identification Level." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9716.
Full textAbstract:
Bioassessment is the concept of evaluating the ecological condition of habitats by surveying the resident assemblages of living organisms. Conducting bioassessment with benthic macroinvertebrates is still evolving and continues to be refined. There are strongly divided opinions about study design, sampling methods, laboratory analyses, and data analysis. Two issues that are currently being debated about study design for bioassessment in streams were examined here: 1) what habitats within streams should be sampled; 2) and is it necessary to identify organisms to the species level? The influence of habitat sampling design and level of taxonomic identification on the interpretation of ecological conditions of ten small streams in western Virginia was examined. Cattle watering and grazing heavily affected five of these streams (impaired sites). The other five streams, with no recent cattle activity or other impact by man, were considered to be reference sites because they were minimally impaired and represented best attainable conditions. Inferential and non-inferential statistical analyses concluded that multiple habitat sampling design was more effective than a single habitat design (riffle only) at distinguishing impaired conditions, regardless of taxonomic level. It appeared that sampling design (riffle habitat versus multiple habitats) is more important than taxonomic identification level for distinguishing reference and impaired ecological conditions in this bioassessment study. All levels of taxonomic resolution, which were studied, showed that the macroinvertebrate assemblages at the reference and impaired sites were very different and the assemblages at the impaired sites were adversely affected by perturbation. This study supported the sampling of multiple habitats and identification to the family level as a design for best determining the ecological condition of streams in bioassessment.Master of Science