Tesis sobre el tema "Freshwater invertebrates"
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She, Shu-sheng. "Determinants of macroinvertebrate community structure on stone surfaces in Hong Kong streams /". [Hong Kong] : University of Hong Kong, 1993. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1373149X.
Texto completoChan, King-tung. "Multivariate analysis of benthic macroinvertebrate communities of Hong Kong streams /". Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18037045.
Texto completoShe, Shu-sheng y 佘書生. "Determinants of macroinvertebrate community structure on stone surfaces in Hong Kong streams". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31233879.
Texto completoFirkins, Ian. "Environmental tolerances of three species of freshwater crayfish". Thesis, University of Nottingham, 1993. http://eprints.nottingham.ac.uk/11282/.
Texto completoRodrigues, Andreia do Carmo Martins. "Combined effects of invasive species and insecticide exposure on freshwater invertebrates". Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22326.
Texto completoFreshwater invertebrate communities are often exposed to multiple stressors that can disrupt aquatic trophic chains and ecosystem functioning. Insecticide contamination and invasive species are two main anthropogenic stressors of concern in freshwaters. Understanding their combined effects to community structure and vital ecosystem functions present challenges for an improved ecological risk assessment. The main objective of this research was thus to investigate whether the deleterious effects of insecticide pollution may be mediated by the presence of alien invasive species. An integrative study was designed to assess the direct and indirect effects of these actual threats to freshwater benthic communities, from the individual towards the community and ecosystem levels with focus on detritus-based food webs. Chlorantraniliprole (CAP), an anthranilic diamide was selected as model compound due to its novel mode of action that confers specificity for ryanodine receptors of insects. Plus, CAP neurotoxicity can potentially disrupt individual behaviour and chemical communication among freshwater species. In a first step, CAP toxicity was assessed and compared with that from a broad-spectrum pyrethroid. Although CAP revealed less toxicity towards the selected species in comparison with the pyrethroid esfenvalerate (ESF), environmentally relevant concentrations of both insecticides disrupted the feeding behaviour of the shredder Sericostoma vittatum and impaired the development of the collector Chironomus riparius. Further, metabolic costs and sub-organismal effects due to insecticide-induced stress were also assessed with different biochemical biomarkers, revealing high energetic costs in exposed organisms. Two biotic factors of high ecological relevance, predation and resource quality, were selected and effects of two widely distributed invasive species (Procambarus clarkii and Eucalyptus globulus) were also considered. Multiple stressors exposures were then performed in microcosms systems with tri-trophic simplified detritus-based food webs to evaluate effects on leaf decomposition, C. riparius development and shredder-collector interactions. In a first trial, combined effects of CAP exposure and predation risk were tested. Shredders presence drastically increased leaf decomposition, but CAP exposure decreased this ecosystem process. CAP toxicity, predation risk and shredders presence independently lead to decreases on C. riparius growth. Additionally, in similar assays, alder and eucalypt leaf decomposition was reduced under predation risk, impairing larvae growth, being this effect exacerbated in the presence of less nutritive eucalypt leaves. In both assays, C. riparius growth was reduced in the presence of the shredders, suggesting a competition between these species, irrespective of CAP exposure or predation risk. Lastly, freshwater benthic communities were exposed to CAP and invasive species presence in mesocosms systems allowing to test the different combinations of stressors under a more complex and realistic exposure scenario. Community responses to CAP were assessed in the presence of leaf litter of different nutritional value (native A. glutinosa vs invasive E. globulus leaves) and the presence of different predators (native dragonfly Cordulegaster boltonii vs invasive crayfish P. clarkii). A path analysis using structural equation modeling (SEM), was applied to identify, quantify and discriminate between the strength of direct and indirect effects of all stressors and their combination on community structure (macroinvertebrate abundances) and ecosystem function (leaf decomposition and primary production). Environmentally relevant exposure to CAP, presence of crayfish and eucalypt leaves all contribute to changes on macroinvertebrate abundances. Crayfish presence mediated CAP toxicity to collectors and grazers. Shredders and collectors survival was reduced in treatments with eucalypt leaves which also presented lower leaf decomposition in comparison with streams with alder leaves. CAP toxicity towards collectors was magnified in the streams with Eucalyptus leaves. Density-mediated effects were observed and reductions of grazer species lead to increased primary production. In summary, this research showed that predator identity and detritus quality can mediate the effects of insecticide contamination on structural and functional endpoints in benthic freshwater communities and highlights the value of incorporating biotic stressors in ecotoxicological experiments. The present thesis is a contribution to the complex task of assessing the effects of pesticides under a more natural and complex scenario of exposure that is, nevertheless, critical for an effective risk management of freshwater ecosystems near agricultural areas.
As comunidades de invertebrados de água doce estão frequentemente expostas a múltiplas pressões que podem perturbar as cadeias tróficas e funções do ecossistema. A contaminação por inseticidas e a presença de espécies invasoras são duas das principais pressões antropogénicas nestes sistemas. Entender os seus efeitos combinados na estrutura e funções das comunidades é um dos atuais desafios para uma melhor avaliação de risco ecológico. O principal objetivo deste estudo foi avaliar se os efeitos deletérios da poluição por inseticidas são mediados pela presença de espécies invasoras. Para tal, foi realizado um estudo integrativo dos efeitos diretos e indiretos destas ameaças para as comunidades bentónicas de água doce, medindo respostas ao nível do indivíduo, da comunidade e ecossistema, com foco em cadeias alimentares de detritos. Chlorantraniliprole (CAP), uma diamida antranílica, foi usado como composto modelo devido ao seu modo de ação que lhe confere especificidade pelos recetores de rianodina de insetos. Além disso, a neurotoxicidade do CAP pode perturbar o normal comportamento e comunicação química entre espécies. Primeiramente, a toxicidade do CAP foi avaliada e comparada com a de um piretróide de amplo espectro. Embora o CAP se tenha revelado menos tóxico para as espécies estudadas que o esfenvalerato (ESF), concentrações ambientalmente relevantes de ambos os inseticidas inibiram a alimentação do fragmentador Sericostoma vittatum e diminuíram o desenvolvimento do coletor Chironomus riparius. Os custos metabólicos e os efeitos ao nível suborganismal foram avaliados através de diferentes biomarcadores bioquímicos, revelando elevados custos energéticos para estes invertebrados quando sob stress químico. Os efeitos de dois fatores bióticos de elevada relevância ecológica, predação e qualidade do recurso alimentar, foram estudados e avaliados alterando a sua identidade por duas espécies invasoras (Procambarus clarkii e Eucalyptus globulus) amplamente distribuídas na Europa. Exposições a múltiplos stressores foram então realizadas em sistemas de microcosmos com cadeias alimentares de detritos simplificadas para avaliar a decomposição de folhada, o crescimento de C. riparius e alterações nas interações fragmentador-coletor. Num primeiro ensaio, foram avaliados os efeitos combinados da exposição a CAP e risco de predação. A presença de fragmentadores aumentou consideravelmente as taxas de decomposição da folhada, mas a contaminação por CAP teve o efeito contrário. A toxicidade do CAP, o risco de predação e a presença de fragmentadores contribuíram para o decréscimo do crescimento de C. riparius. Em ensaios similares, a decomposição da folhada de amieiro e eucalipto foi reduzida sob risco de predação, diminuindo o crescimento das larvas, sendo este efeito exacerbado com eucalipto, de menor valor nutricional. Em ambos os ensaios, o crescimento de C. riparius foi reduzido na presença dos fragmentadores, sugerindo uma competição entre estas espécies, independentemente da exposição a CAP ou presença do predador. Por fim, comunidades bentónicas de água doce foram expostas a CAP e presença de espécies invasoras em mesocosmos, permitindo testar as diferentes combinações de stressores sob um cenário de exposição mais relevante. As respostas das comunidades ao CAP foram avaliadas na presença de folhada de diferentes valores nutricionais (da nativa Alnus glutinosa vs folhas da invasora E. globulus) e na presença de diferentes predadores (odonata nativo Cordulegaster boltonii vs lagostim invasor P. clarkii). Para identificar, quantificar e discriminar a magnitude dos diversos efeitos diretos, indiretos e combinados dos vários stressores sobre a estrutura da comunidade (abundância de macroinvertebrados) e função do ecossistema (decomposição foliar e produção primária), utilizou-se um método de análise de equações estruturais (SEM). Concentrações ambientalmente relevantes de CAP, a presença do lagostim e das folhas de eucalipto, contribuíram para alterações na abundância de macroinvertebrados. A presença do lagostim mediou os efeitos tóxicos do CAP para coletores e herbívoros. A sobrevivência dos fragmentadores e coletores foi reduzida nos tratamentos com folhada de eucalipto, que por sua vez também apresentaram menor decomposição em comparação com os rios com folhada de amieiro. A toxicidade do CAP para os coletores foi magnificada em rios com eucalipto como recurso alimentar. Efeitos mediados pela densidade foram observados através da redução de herbívoros que levou ao aumento de produção primária. Em síntese, este estudo demonstra que a identidade do predador e a qualidade dos recursos alimentares podem mediar os efeitos da contaminação por inseticidas em parâmetros estruturais e funcionais das comunidades bentónicas de água doce e destaca o valor da incorporação de stressores bióticos em testes ecotoxicológicos. A presente tese é um contributo para a complexa tarefa de avaliar os efeitos dos pesticidas considerando cenários de exposição ecologicamente relevantes que é, no entanto, crítica para uma avaliação de risco eficaz em ecossistemas de água doce perto de áreas agrícolas.
Tan, Thomas Ching-Jen. "Telomere biology in the freshwater planarian Schmidtea mediterranea". Thesis, University of Nottingham, 2011. http://eprints.nottingham.ac.uk/12308/.
Texto completoOrtiz, Natali Ortiz. "The effect of pond dyes on mosquitoes and other freshwater invertebrates". Thesis, University of Reading, 2018. http://centaur.reading.ac.uk/77950/.
Texto completoSimaika, John Pascal. "Practical conservation planning from local to continental scales using freshwater invertebrates". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/18051.
Texto completoENGLISH ABSTRACT: Dragonflies (Insecta: Odonata) are a valuable tool for assessing aquatic systems and have been used as indicators of ecological health, ecological integrity, and environmental change, including climatic change. In four separate studies I explored the usefulness of dragonflies as surrogates in biomonitoring, site prioritization and indication of global climate change. In the use of dragonflies for biomonitoring, I field-tested a freshwater ecological integrity index, the Dragonfly Biotic Index (DBI), based on dragonfly assemblages at the local scale, and compared the DBI to a standard freshwater benthic macroinvertebrate-based freshwater health index. Overall, dragonflies were more sensitive to changes in river condition than were macroinvertebrates, and the DBI site value and macroinvertebrate scores were highly significantly correlated. I conclude that dragonfly assemblages in the form of a DBI are an excellent tool for environmental assessment and monitoring freshwater biodiversity, with the potential to replace benthic macroinvertebrate-based freshwater quality assessments. In the second study, I used the DBI to prioritize sites for conservation action in South Africa. Using a selected set of top prioritized sites, I compared the DBI’s performance to that of a rarity-complementarity algorithm. Site prioritization using the DBI reveals that CFR sites protect Red Listed taxa rather well. The rarity-complementarity algorithm represents all species, but without greater emphasis on the rare and threatened species. I conclude that the DBI is of great value in selecting biodiversity hotspots, while the algorithm is useful for selecting complementarity hotspots. The third study was made possible by the recent completion of a continental assessment of freshwater biodiversity, which revealed that patterns of richness and threat of four well-studied aquatic taxa largely coincide at the continental scale. Using only dragonflies, I built a protected areas network for Africa using spatial planning software. I then compared the performance of the existing African reserve network and that of known global biodiversity hotspots against the model, and identified sites of conservation concern. Although the current reserve network covers 10.7% of the landscape, the proportional representation of species geographic distributions in reserves is only 1.1%. The reserve network is therefore inefficient, and many areas of conservation priority that are not formally protected remain. The advantage of operating at the fine scale, while covering a large geographic area is that it shifts the focus from the large-scale hotspots to smaller priority areas within and beyond hotspots. In the fourth study, I created species distribution models of dragonflies in an El Niño-prone biodiversity hotspot in South Africa, and predicted the changes in species richness, geographic range and habitat suitability, forty and eighty years from now. According to the model results of two different emissions scenarios, at least three species will be lost from the area by 2050, and four by 2080. The remaining species are predicted to persist with reduced geographical ranges, at generally higher elevations. Most species presented here thrive quite well in artificial environments, that is, engineered ponds or dams. It is therefore unlikely that loss in connectivity will play a role for these species.
AFRIKAANSE OPSOMMING: Naaldekokers (Insecta:Odonata) is waardevolle instrumente om akwatiese sisteme te assesseer, en is al gebruik as aanwysers van ekologiese gesondheid, ekologiese integriteit en omgewingsverandering, insluitend klimaatsverandering. In vier studies het ek die nut van naaldekokers as surrogate in biomonitering, area prioritisering en indikasie van globale klimaatsverandering ondersoek. In die benutting van naaldekokers in biomonitering, het ek ´n varswater ekologiese integriteits indeks, die Dragonfly Biotic Index (DBI), wat gebaseer is op naaldekokergemeenskappe op die plaaslike skaal, getoets en dit vergelyk met ´n standaard bentiese makroinvertebraat-gebaseerde varswater gesondheids index. Naaldekokers was meer sensitief vir veranderinge in riviertoestand as makroinvertebrate, en die DBI lokaliteit waarde en makroinvertebraat telling was beduidend gekorreleer. Die gevolgtrekking was dat naaldekoker gemeenskappe in die vorm van die DBI ‘n uitstekende instrument is vir omgewings assessering en die monitering van varswater biodiversiteit, met die potensiaal om bentiese makroinvertebraat-gebaseerde varswaterkwaliteit assessering te vervang. In die tweede studie, het ek die DBI gebruik om areas te prioritiseer vir bewaringsaksie in Suid Afrika. Met die gebruik van ‘n geselekteerde set top prioriteit areas, het ek die DBI se prestasie vergelyk met die van ‘n rariteit-komplemetariteit algoritme. Area prioritisering met die gebruik van die DBI het aangedui dat CFR areas taxa op die Rooi Lys goed beskerm. Die rariteit-komplementariteit algoritme verteenwoordig alle spesies, maar beklemtoon minder skaars en bedreigde spesies. Die gevolgtrekking was dat die DBI van meer waarde is in die selektering van biodiversiteits ‘hotspots‘, terwyl die algoritme nuttig is vir die selektering van komplementariteits ‘hotspots‘. Die derde studie was moontlik gemaak deur die onlangse voltooiing van ‘n kontinentale assessering van varswater biodiversiteit, wat aangedui het dat patrone van rykheid en bedreiging van vier goed-bestudeerde akwatiese taxa grootliks ooreenstem op die kontinentale skaal. Met die gebruik van naaldekokers, het ek ‘n beskermde area netwerk gebou vir Afrika met ruimtelike beplannings sagteware. Ek het die prestasie van die bestaande Afrika reservaatnetwerk en die van bekende globale biodiversiteit ‘hotspots‘ vergelyk teen die model, en het areas van bewaringsbelang geidentifiseer. Alhoewel die bestaande reservaatnetwerk 10.7% van die landskap dek, is die proporsionele verteenwoordiging van spesies se geografiese verspreiding net 1.1%. Die reservaatnetwerk is dus onvoldoende en baie areas van bewaringsbelang is nie formeel beskerm nie. Die voordeel van op die fyn skaal werk terwyl ‘n groot geografiese are gedek word, is dat dit die fokus van groot skaal ‘hotspots‘ na kleiner prioriteits areas binne en buite ‘hotspots‘ verskuif. In die vierde studie, het ek spesies verspreidingsmodelle van naaldekokers geskep in ‘n El Nino-geneigde biodiversiteits ‘hotspot’ in Suid Afrika, en het veranderinge in spesies rykheid, geografiese verspreiding en habitatsgeskiktheid voorspel, veertig en tagtig jaar van nou af. Volgens die modelresultate van twee verskillende emissie scenarios, sal ten minste drie spesies verlore gaan uit die area teen 2050, en vier teen 2080. Daar word voorspel dat die oorblywende spesies sal voortduur in verkleinde geografiese areas, by groter hoogte bo seespieël. Die meeste spesies hier verteenwoordig floreer in kunsmatige omgewings, soos mensgemaakte damme. Dit is dus onwaarskynlik dat ‘n verlies in konnektiwiteit ‘n rol sal speel vir hierdie spesies.
Cappo, Michael. "Frogs as predators of organisms of aquatic origin in the Magela Creek system, Northern Territory /". Title page, contents and summary only, 1986. http://web4.library.adelaide.edu.au/theses/09SM/09smc249.pdf.
Texto completoElangovan, Ramalingam. "Accumulation and distribution of aluminium in two freshwater invertebrates at neutral pH". Thesis, University of Manchester, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488074.
Texto completoO'Neill, Anne Jennie. "Biomarkers of chemical impacts in the freshwater invertebrates Asellusaquaticus and Pacifastacus leniusculus". Thesis, University of Plymouth, 2004. http://hdl.handle.net/10026.1/1687.
Texto completoCowley, C. "The influence of road runoff on the benthic macro-invertebrates of an unpolluted chalk stream". Thesis, University of Westminster, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354965.
Texto completoCheung, Ka-wing. "Spatial and seasonal variations of freshwater macroinvertebrates, odonata and waterbirds in Luk Keng marshland, Hong Kong". Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B41290951.
Texto completoHansen, Jonathan Ford. "Long-term implications of dam removal for mesohabitat and macroinvertebrate communities in Michigan and Wisconsin rivers". Diss., Connect to online resource - MSU authorized users, 2008.
Buscar texto completoKhan, 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.
Texto completoChan, King-tung y 陳勁東. "Multivariate analysis of benthic macroinvertebrate communities of HongKong streams". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31213911.
Texto completoHolthuis, Bernadette Veronica. "Evolution between marine and freshwater habitats : a case study of the gastropod Neritopsina /". Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/5195.
Texto completoCuster, Kevin Wayne. "FACTORS CONTROLLING NICKEL BIOAVAILABILITY AND EFFECTS ON BENTHIC INVERTEBRATES IN HARDWATER FRESHWATER STREAMS". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1364295154.
Texto completoSpann, Nicole. "Freshwater bivalves as biomonitors of metal pollution". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610276.
Texto completoWood, Diane L. "The influence of abiotic factors on lotic insect communities of submerged rootmats and temporary pools /". free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9964013.
Texto completoLeung, Sze-lun. "Scale-dependent effects of spatial and temporal variability on benthic macroinvertebrate communities in Hong Kong streams /". Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B25334542.
Texto completoDriver, Patrick y n/a. "The role of carp (Cyprinus carpio L) size in the degradation of freshwater ecosystems". University of Canberra. School of Resources, Environmental and Heritage Sciences, 2002. http://erl.canberra.edu.au./public/adt-AUC20050404.110223.
Texto completoStendera, Sonja Johnson Richard K. "Spatiotemporal variability of chemistry and biota in boreal surface waters : a multiscale analysis of patterns and processes /". Uppsala : Swedish University of Agricultural Sciences, 2005. http://diss-epsilon.slu.se/archive/00000956/.
Texto completoThesis documentation sheet inserted. Appendix reproduces four papers and manuscripts co-authored with R.K. Johnson. Issued also electronically via World Wide Web in PDF format; online version lacks appendix.
JIANG, HUAN. "Ecological Risk Assessment of Salts in Swedish Freshwater Ecosystem : A preliminary assessment for invertebrates and vertebrates". Thesis, Högskolan i Halmstad, Sektionen för ekonomi och teknik (SET), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-16578.
Texto completoWidenfalk, Anneli. "Interactions between pesticides and microorganisms in freshwater sediments : toxic effects and implications for bioavailability /". Uppsala : Dept. of Environmental Assessment, Swedish University of Agricultural Sciences, 2005. http://epsilon.slu.se/200523.pdf.
Texto completoMichael, Taylor. "Invertebrate Activities in Wetland Sediments Influence Oxygen and Nutrient Dynamics at the Sediment-water Interface". Kent State University Honors College / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1525568331200468.
Texto completoUys, Amanda Cloete. "The invertebrates of temporary rivers in the Eastern Cape, South Africa". Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004908.
Texto completoWeiss, Steven P. "Bioassessment of the West Branch of the Wolf River /". Link to full text, 2007. http://epapers.uwsp.edu/thesis/2007/weiss.pdf.
Texto completoVeenstra-Quah, Anneke Alison y mikewood@deakin edu au. "The impact of stresses imposed on macroinvertebrate communities in two urban streams". Deakin University. School of Biological and Chemical Sciences, 1999. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050815.102219.
Texto completoBernard, David P. "Impact of stream acidification on invertebrates : drift response to in situ experiments augmenting aluminum ion concentrations". Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24478.
Texto completoScience, Faculty of
Zoology, Department of
Graduate
Gustafsson, Pär. "Forest – stream linkages : Brown trout (Salmo trutta) responses to woody debris, terrestrial invertebrates and light". Doctoral thesis, Karlstads universitet, Avdelningen för biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-6731.
Texto completoMabidi, Annah. "Freshwater invertebrate assemblages of the Eastern Cape Karoo region (South Africa) earmarked for shale gas exploration". Thesis, Nelson Mandela University, 2017. http://hdl.handle.net/10948/13713.
Texto completoOrzetti, Leslie LuChar. "Stream community structure an analysis of riparian forest buffer restoration in the Chesapeake Bay watershed /". Full text available online (restricted access), 2004. http://images.lib.monash.edu.au/ts/theses/Orzetti.pdf.
Texto completoRogers, Megan Bryn. "Woody debris and macroinvertebrate community structure of low-order streams in Colville National Forest, Washington". Connect to this title online, 2003. http://www.dissertations.wsu.edu/Thesis/Fall2003/m%5Frogers%5F121503.pdf.
Texto completoCheung, Ka-wing y 張嘉穎. "Spatial and seasonal variations of freshwater macroinvertebrates, odonata and waterbirds in Luk Keng marshland, Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B41290951.
Texto completoCastro, López Daniel. "Riparian forest quality, land-use dynamics and their influence on macroinvertebrate communities. An evaluation of the ecological status of Pesquería River (N.E., Mexico)". Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668280.
Texto completoA nivel mundial, la diversidad biológica está disminuyendo a un ritmo sin precedentes. Los cambios ambientales actuales están causando crisis hídricas, ecológicas y de biodiversidad que, junto con el cambio climático, están afectando los patrones del paisaje y los esfuerzos de desarrollo sostenible. Por lo tanto, las presiones antropogénicas están cambiando los paisajes del mundo de manera generalizada. Además, estas presiones antropogénicas en el paisaje natural se han asociado con cambios en el paisaje y en las condiciones ecológicas de los ecosistemas de agua dulce. Esto es importante para los países en desarrollo, dado que sus ecosistemas están amenazados por actividades antropogénicas. Además, la falta de investigación, legislación y gestión dificultan los planes de restauración y conservación de sus ecosistemas de agua dulce. En este contexto, el objetivo general de esta tesis doctoral es evaluar el estado ecológico del río Pesquería y evaluar los efectos de la degradación del paisaje a lo largo de su canal ribereño. En esta tesis doctoral demostramos que el análisis de dinámicas de uso de suelo a nivel de los canales ribereños debe verse como una herramienta para la mejora de los ecosistemas acuáticos en México. Observamos la importancia de considerar el ancho del amortiguador ribereño como un ecosistema, no como un área federal, para proteger los ecosistemas acuáticos de México. Corroboramos la eficiencia de la adaptación del QBR-RNMX para usarse en el establecimiento de planes de restauración y contingencia para eliminar especies invasoras del río Pesquería. Esta tesis doctoral proporcionó once métricas biológicas y treinta y dos taxones representativos que pueden usarse como bioindicadores en futuras investigaciones. Sin embargo, se necesitan más estudios, y especialmente la relación de este índice con las presiones del río para establecer un índice para el río Pesquería en el futuro. Además, en la discusión general, proponemos un índice basado en macroinvertebrados como un primer paso para la evaluación del estado ecológico del río. Finalmente, nuestros hallazgos sugieren la creación de un marco mexicano similar a la Directiva Marco del Agua Europea, donde la calidad ecológica del río debería ser el objetivo principal de la recuperación de los ecosistemas ribereños.
Engel, Sarah Rose. "The effectiveness of using volunteers for biological monitoring of streams". Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/31060.
Texto completoMaster of Science
Mazzini, Flávia. "Efeitos da resolução taxonômica de invertebrados bentônicos no diagnóstico da qualidade de ecossistemas lóticos". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/91/91131/tde-22102007-111107/.
Texto completoIn the last decades, it has been observed an expressive deterioration of the environmental quality and biodiversity loss in the aquatic ecosystems as function of anthropogenic activities. Considering that communities' structure can be altered by such disturbances, several methods have been proposed for quality assessment in those ecosystems, standing out, among them, the use of the benthic macroinvertebrates. Some studies using these indicators defend the generic level identification as they supply more information, result in more reliable environmental classifications and present better distinction capacity among sites, when compared to broader levels. However, in most of the works the identification of this group is limited to the family level, mainly due to resources saving during the identification, which is not justified in the case this level misses information to classification aims. In this work, comparison of current biological evaluations through Chironomidae identification structural indexes at the generic level with the one at sub-family/tribe was evaluated. Benthic organisms samples, as well as physical, chemical and microbiological data were collected in seven sampling sites, from several projects taken along different years by CETESB (Company of Technology of Environmental Sanitation), which classified the environment as, according to ICBRIO (Benthic Community Index for rivers), worst, bad, regular, good and excellent quality. The collections were standardized to winter period and to type of sample habitat (depositional river margin). Triplicates were obtained with modified Ponar and Petersen grabs on retained material by 0.5mm-mesh sieve. Counting and identification based on specialized literature were done with the stereomicroscope, and optical microscope. To define the quality gradient, the environmental variables were submitted to a Cluster Analysis by the Ward method, using the simple Euclidean Distance. Density values were lumped on a Bray-Curtis distance matrix by the Unweighted Pair Group method in order to verify the similarity degree among the points and the interferences of taxonomic identification level on the formed associations. Aiming to check the sensibility of the data taxonomic level to the environmental quality gradient, as well as to test the possible influence of taxonomic refinement in the ICBRIO's sensibility, several metrics (Richness, Shannon-Wiener Diversity Index, Sequential Comparison Index, Dominance of Tolerant Groups and Richness of Sensitive Taxa) were used. Seeking the diagnosis of the environmental conditions, reducing costs and manipulation time of the samples, but keeping relevant information to subsidize the policy managers, the present work discards the need of the generic resolution level in the Chironomidae larvae identification. The exposed results confirmed the applicability of ICBRIO with the identification of this group at sub-family/tribe levels on the environmental quality assessment, demonstrating no need of eventual modification in the method.
Villamagna, Amy Marie. "Ecological effects of water hyacinth (Eichhornia crassipes) on Lake Chapala, Mexico". Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26854.
Texto completoPh. D.
Seymour, Karen. "The influence of salmon presence on benthic communities in three Puyallup-White River tributaries". Online pdf file accessible through the World Wide Web, 2007. http://archives.evergreen.edu/masterstheses/Accession86-10MES/Seymour_K%20MESThesis.pdf.
Texto completoUntersteiner, Hubert. "Aquatic invertebrates as indicators to pollution-induced stress validation of the locomotory behaviour of freshwater and marine crustaceans as response to sublethal heavy metal stress". Saarbrücken Suedwestdeutscher Verlag fuer Hochschulschriften, 2009. http://www.svh-verlag.de.
Texto completoCarini, Giovannella y n/a. "Effects of Contemporary and Historical Processes on Population Genetic Structure of Two Freshwater Species in Dryland River Systems (Western Queensland, Australia)". Griffith University. Australian School of Environmental Studies, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20050113.081250.
Texto completoCarini, Giovannella. "Effects of Contemporary and Historical Processes on Population Genetic Structure of Two Freshwater Species in Dryland River Systems (Western Queensland, Australia)". Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367070.
Texto completoThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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Johansson, June. "Sediment chemistry and the potential toxicity to benthic invertebrates in sediments affected by acid sulfate soils : A study on freshwater and marine sediments in Västerbotten, Sweden". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-172323.
Texto completoMuir, William Douglas. "Macroinvertebrate drift abundance below Bonneville Dam and its relation to juvenile salmonid food habits". PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/4108.
Texto completoBrowne, Samantha. "The role of acute toxicity data for South African freshwater macroinvertebrates in the derivation of water quality guidelines for salinity". Thesis, Rhodes University, 2005. http://eprints.ru.ac.za/174/.
Texto completoPerfect, Charles. "From engineered channel to functioning stream ecosystem : rates, patterns and mechanisms of development in a realigned river channel". Thesis, University of Stirling, 2010. http://hdl.handle.net/1893/2431.
Texto completoSchwarz, Simon [Verfasser]. "Effects of the anti-inflammatory drug diclofenac and the beta-blocker metoprolol in brown trout Salmo trutta f. fario and freshwater invertebrates at different levels of biological organization / Simon Schwarz". Tübingen : Universitätsbibliothek Tübingen, 2019. http://d-nb.info/1228814902/34.
Texto completoNebra, 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.
Texto completoEl 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.
梁士倫 y Sze-lun Leung. "Scale-dependent effects of spatial and temporal variability on benthicmacroinvertebrate communities in Hong Kong streams". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31243319.
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