Dissertations / Theses on the topic 'Ecological systems'
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Дегтярьова, Ія Олександрівна, Ия Александровна Дегтярева, Iia Oleksandrivna Dehtiarova, and D. Snitko. "Ecological-economic systems efficiency." Thesis, Видавництво СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/7833.
Full textMilner, Rebecca J. "Ecological Systems in Action." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/2977.
Full textДегтярьова, Ірина Борисівна, Ирина Борисовна Дегтярева, and Iryna Borysivna Dehtiarova. "Synergism of ecological-economic systems." Thesis, Вид-во СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/8090.
Full textLascoutx, Ruiz Alfredo. "A Politico-Ecological Approach of Transitional Spaces In Social Ecological Systems." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/41987.
Full textМельник, Леонід Григорович, Леонид Григорьевич Мельник, Leonid Hryhorovych Melnyk, Ірина Борисівна Дегтярьова, Ирина Борисовна Дегтярева, and Iryna Borysivna Dehtiarova. "Synergetic effects of ecological-economic systems." Thesis, Видавництво СумДУ, 2009. http://essuir.sumdu.edu.ua/handle/123456789/7920.
Full textLopes, Marta Filipa Lobão. "Ecological quality assessment in transitional systems." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14856.
Full textEstuaries are poles of attraction for human settlement which is a source of pressures to surface water bodies. The implementation of the European Water Framework Directive (WDF, 2000/60/EC) has increased the investigation in order to develop methodologies to assess the Ecological Quality Status (EQS) of aquatic ecosystems. Transitional systems are naturally stressed and characterized by highly dynamic physical, chemical and hydro-morphologic conditions and by species with a higher level of tolerance to change, being more difficult to develop suitable quality indicators for these systems. The general purpose of this study is to test the ability of synthesis descriptors, including primary (S, taxa richness) and derived biological variable (H’, Shannon-Wiener diversity), biotic indices (AMBI and M-AMBI), body size properties (abundance distribution by body size classes, length, weight and length-weight relationships) and non-taxonomic indices (ISS), as well as functional indicators related to the decomposition rates of various experimental substrates, a macrophyte (Phragmites australis) and an alga (Fucus vesiculosus), to evaluate the environmental quality in transitional systems. This study was carried out in one of the most pristine channels of the Ria the Aveiro, Mira Channel, along a full salinity gradient and in a metals and metalloid sediment contamination area, the Estarreja Channel, and two reference channels (Canelas and Salreu). In this study were used different sampling techniques, the leaf-bag technique and a hand-held corer. In Mira Channel, the alga and the macrophyte presented an opposite trend in the decomposition rate along the salinity gradient, with the decomposition rates of the alga always higher than those of the macrophyte. The decomposition rates of the macrophyte and the alga were higher in the mid estuary and in higher salinity areas, respectively, corresponding to the preferencial distribution areas of each species. The macrobenthic fauna associated with the decaying and an artificial substrate (control) showed equally well the benthic succession from the marine to the freshwater areas and, despite the strong differences in the decay rates, no significant differences were found between the benthic communities associated with the alga and the macrophyte. The body size properties of the macrobenthic fauna associated with the P. australis leaf-bag (1mm and 5mm) and corer samples were studied along the full salinity gradient. The dominant species of the sub-set of measured specimens were not the same of the original macrobenthic fauna sampled but, despite that, the sub-set of measured specimens was also able to show the benthic succession from the marine to the freshwater areas. The body size abundance distribution of the benthic macroinvertebrates according to the ISS size classes did not show a particular trend in any sampler along the salinity gradient. Significant differences were found in the length, weight and length-weight relationships of Annelids, , Molluscs and even some species along the salinity gradient. No significant differences were found in the AMBI, M-AMBI and ISS values along the salinity gradient for all the samplers. The EQS of the corer samples obtained using the M-AMBI was lower than that of the leaf-bags. The EQS obtained with the ISS was higher than that obtained with the M-AMBI in the leaf-bags but not in the corer samples. The ecological effects of contaminated sediments associated with the industrial chemical effluents discharged in the Estarreja Channel were studied a decade after ceasing the emissions, using the Sediment Quality Triad approach and two reference channels. The results showed that despite the emissions ceased in 2004, the sediment remains polluted with high levels of metals and metalloid, available to bioaccumulation and with severe consequences at the community level. The sediment contamination problem was also studied using the leaf-bag technique with a macrophyte, an alga and a control substrate. The results showed that the decay rates, the associated macrofauna and the application of the AMBI, M-AMBI and ISS indices to the mesh-bag samples were not able to identify the sediment contamination. Contrarily to the AMBI, the M-AMBI and the ISS showed significant differences between the contaminated and the reference channels for the corer samples. Although such statistical significance, the interest of using these complex biotic indices could be questioned, when much simple ones, like the S and H’ allow to reach the same conclusions.
Os estuários são pólos de atração para a instalação de aglomerados humanos, constituindo uma fonte de pressão para as massas de água superficiais. Com a implementação da Diretiva Europeia Quadro da Água (DQA, 2000/60/CE) tem aumentado a investigação no sentido de desenvolver metodologias para avaliar o estado de qualidade ecológica (EQE) dos ecossistemas aquáticos. Os sistemas de transição são caracterizados por condições físico-químicas e hidromorfológicas extremamente dinâmicas e por espécies com uma maior tolerância à mudança, sendo difícil desenvolver indicadores de qualidade adequados para estes ecossistemas. O objetivo deste estudo é testar a capacidade de descritores de síntese, tais como a riqueza em espécies (S) e a diversidade de Shannon-Wiener (H'), índices de base taxonómica (AMBI e M-AMBI) e não taxonómica (ISS), as propriedades do tamanho corporal (distribuição de abundância por classes de tamanho corporal, comprimento, peso e relações comprimento-peso), bem como indicadores funcionais (taxas de decomposição de uma macrófita (Phragmites australis) e uma alga (Fucus vesiculosus)), para avaliar a qualidade ambiental dos sistemas de transição. Este estudo foi realizado ao longo de um gradiente completo de salinidade num dos canais com menor impacto antropogénico da Ria de Aveiro, o Canal de Mira, numa área com contaminação sedimentar por metais e metaloides, o Canal de Estarreja, e dois canais de referência (Canelas e Salreu). Neste estudo foram utilizadas diferentes técnicas de amostragem, a técnica dos sacos de folha e corers. No Canal de Mira, a alga e a macrófita apresentaram uma tendência oposta na taxa de decomposição ao longo do gradiente de salinidade, com as taxas de decomposição da alga sempre superiores. As taxas de decomposição da macrófita e da alga foram mais elevadas a meio do estuário e em áreas de maior salinidade, respetivamente, correspondendo às preferenciais áreas de distribuição de cada espécie. A fauna bentónica associada aos substratos orgânicos e a um substrato artificial (controlo) mostrou a sucessão bentónica ao longo do gradiente estuarino e, apesar das grandes diferenças nas taxas de decomposição, não foram encontradas diferenças nas comunidades bentónicas entre ambos os substratos. As propriedades do tamanho corporal da fauna bentónica dos sacos de folhas de P. australis (1mm e 5mm) e corers foram estudadas ao longo do gradiente estuarino. As espécies dominantes do sub-conjunto de espécimes medidos não são as mesmas da fauna bentónica original mas, apesar disso, foram capazes de mostrar a sucessão bentónica ao longo do gradiente salino. A distribuição da abundância pelas classes de tamanho estabelecidas para o cálculo do índice ISS não mostrou nenhuma tendência ao longo do gradiente de salinidade em nenhum dos amostradores. Foram encontradas diferenças significativas no comprimento, peso e na relação comprimento-peso dos Anelídeos, Artrópodes, Moluscos e de algumas espécies ao longo do gradiente de salinidade. Não foram encontradas diferenças significativas nos valores AMBI, M-AMBI e ISS ao longo do gradiente estuarino. O EQE das amostras dos corer foi inferior ao dos sacos de folhas. O EQE obtido com o ISS foi mais elevado do que o obtido com o M-AMBI nos sacos de folha, mas não nas amostras do corer. Os efeitos ecológicos associados à contaminação dos sedimentos por efluentes químicos lançados no Canal de Estarreja foram estudados uma década após a sua cessação, recorrendo à Tríade de Qualidade Sedimentar e dois canais de referência. Os resultados mostraram que o sedimento permanece contaminado com elevados níveis de metais e metaloide, disponíveis para serem bioacumulados e com graves consequências ao nível da comunidade. A contaminação do sedimento foi também estudada utilizando a técnica dos sacos de folhas com a macrófita, a alga e um substrato de controlo, tendo-se verificado que as taxas de decomposição, a macrofauna associada e a aplicação dos índices AMBI, M-AMBI e ISS aos sacos de folhas não foram capazes de identificar o problema. Ao contrário do AMBI, o M-AMBI e o ISS apresentaram diferenças significativas entre o canal contaminado e os canais de referência para as amostras do corer. No entanto, a utilização de índices tão complexos é questionável, na medida em que índices mais simples, tais como a S e a H', permitem chegar às mesmas conclusões.
Sheppy, Margarette Isabell. "An ecological-systems analysis of anorexia nervosa." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/26044.
Full textEducation, Faculty of
Educational and Counselling Psychology, and Special Education (ECPS), Department of
Graduate
Law, Derek M. "ECOLOGICAL WEED MANAGEMENT FOR ORGANIC FARMING SYSTEMS." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_theses/414.
Full textWhite, Andrew. "Temporal and spatial dynamics of ecological systems." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338459.
Full textReynolds, Jennifer Joan Heather. "Drivers of population cycles in ecological systems." Thesis, Heriot-Watt University, 2012. http://hdl.handle.net/10399/2530.
Full textТерещенко, Ірина Володимирівна, Ирина Владимировна Терещенко, and Iryna Volodymyrivna Tereshchenko. "Self-management in ecological and economical systems." Thesis, Видавництво СумДУ, 2012. http://essuir.sumdu.edu.ua/handle/123456789/26798.
Full textPeng, Qiuliang. "Periodic differential systems with applications to ecological modelling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0006/NQ29093.pdf.
Full textGuttal, Vishwesha. "Applications of nonequilibrium statistical physics to ecological systems." Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1209696541.
Full textvon, Heland Jacob. "Rowing social-ecological systems: morals, culture and resilience." Doctoral thesis, Stockholms universitet, Systemekologiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-62422.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript. Paper 5: Submitted. Paper 6: In press.
Kuang, Yan. "Modeling and analysis of competing dynamic ecological systems." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35555.
Full textDepartment of Industrial & Manufacturing Systems Engineering
David H. Ben-Arieh
The dynamic relationship between competing ecological systems has long been and will continue to be one of vital topics in both ecology and mathematical ecology because of its importance and universal existence. Mathematical modeling has become an effective tool to model and simulate the dynamic system, providing decision makers with strategy recommendations. Although a great amount of previous work has attempted to model the biological mechanisms including dispersal, only rarely has there been a systematic investigation on different spatial effects. The author introduces spatial games as a modeling approach with different constructions towards different dynamic systems in order to benefit from the systematic research on spatial dynamics when studying the competing ecological systems. This research developed models of two systems: (1) two-spotted spider mite prey-predator system; (2) tomato spotted wilt virus (TSWV) and west flower thrips (WFT) vector-borne disease system. For two-spotted spider mite system, the author presented four spatial mathematical models as well as a novel spatial game model to describe the spatial movement of two competing species. For the TSWV-WFT system, a spatial game was introduced to describe the spatial dynamics of adult thrips and the novel model was validated with experimental data. The author also gave suggestions for efficiently controlling the vector-borne disease by performing sensitivity analysis towards parameters. The major contribution of this research is to introduce spatial games as a tool to describe the dynamic schemes in ecological systems. Compared to a traditional dynamic model, a spatial game model is more expressive and informative. This approach uses a payoff function and a movement probability function that can be adjusted based on habits, characteristics and mobility schemes of different competing entities, which has enriched its modeling power. The methodology and modeling approach used in this dissertation can be applied to other competing species dynamic systems, and have a broad impact on research areas related to mathematical ecology, biology modeling, epidemiology, pest control, vector-borne disease control, and ecological decision-making processes.
Haag, Daniel. "Models for the representation of ecological systems? the validity of experimental model systems and of dynamical simulation models as to the interaction with ecological systems /." [S.l.] : [s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=962066893.
Full textHaag, Daniel. "Models for the representation of ecological systems? the validity of experimental model systems and of dynamical simulation models as to the interaction with ecological systems /." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9386085.
Full textAbram, Joseph James. "An evaluation of structural loop analysis on dynamic models of ecological and socio-ecological systems." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/426888/.
Full textDalmazzone, Silvana. "Economic activity and the resilience of ecological systems : complexity, nonlinearities and uncertainty in economic-ecological modelling." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311013.
Full textTomlinson, Benjamin John. "Modelling Social-Ecological Systems in the Catalan Coastal Zones." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/384929.
Full textVander, Meer Elizabeth. "Resisting Incorporation : Considering Biodiversity Beyond Ecological and Economic Systems." Thesis, Lancaster University, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518144.
Full textGuimaraes, Nuno Ana. "Managing social-ecological systems under uncertainty : implications for conservation." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/18974.
Full textMancy, Rebecca. "Modelling persistence in spatially-explicit ecological and epidemiological systems." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/6219/.
Full textMacpherson, Morag Fiona. "Modelling population and disease dynamics in complex ecological systems." Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2824.
Full textWeerasena, Lakmali. "Optimization models for designing spatially compact ecological reserve systems." Connect to this title online, 2009. http://etd.lib.clemson.edu/documents/1253031678/.
Full textMacKinnon, Richard A. "Examining the work-home interface : an ecological systems perspective." Thesis, University of East London, 2012. http://roar.uel.ac.uk/1599/.
Full textPeres, Edna M. "The translation of ecological resilience theory into urban systems." Thesis, University of Pretoria, 2016. http://hdl.handle.net/2263/56100.
Full textThesis (PhD)--University of Pretoria, 2016.
tm2016
Architecture
PhD
Unrestricted
Rodrigues, Carla Cristina Morbey. "Topological and dynamical complexity in epidemiological and ecological systems." Doctoral thesis, Universidade de Évora, 2017. http://hdl.handle.net/10174/21241.
Full textHentati-Sundberg, Jonas. "SEA CHANGE : Social-ecological co-evolution in Baltic Sea fisheries." Doctoral thesis, Stockholms universitet, Stockholm Resilience Centre, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-122372.
Full textAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.
Campanaro, Richard. "Socio-ecological coevolution : an ecological analysis of the historical development of international systems in the circumpolar Arctic." Thesis, London School of Economics and Political Science (University of London), 2012. http://etheses.lse.ac.uk/566/.
Full textBarfuss, Wolfram. "Learning dynamics and decision paradigms in social-ecological dilemmas." Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20127.
Full textCollective action is required to enter sustainable development pathways in coupled social-ecological systems, safely away from dangerous tipping elements. Without denying the usefulness of other model design principles, this thesis proposes the agent-environment interface as the mathematical foundation for the design of social-ecological system models. First, this work refines techniques from the statistical physics literature on learning dynamics to derive a deterministic limit of established reinforcement learning algorithms from artificial intelligence research. Illustrations of the resulting learning dynamics reveal a wide range of different dynamical regimes, such as fixed points, periodic orbits and deterministic chaos. Second, the derived multi-state learning equations are applied to a newly introduced environment, the Ecological Public Good. It models a coupled social-ecological dilemma, extending established repeated social dilemma games by an ecological tipping element. Known theoretical and empirical results are reproduced and novel qualitatively different parameter regimes are discovered, including one in which these reward-optimizing agents prefer to collectively suffer in environmental collapse rather than cooperating in a prosperous environment. Third, this thesis challenges the reward optimizing paradigm of the learning equations. It presents a novel formal comparison of the three decision paradigms of economic optimization, sustainability and safety for the governance of an environmental tipping element. It is shown that no paradigm guarantees fulfilling requirements imposed by another paradigm. Further, the absence of a master paradigm is shown to be of special relevance for governing the climate system, since the latter may reside at the edge between parameter regimes where economic welfare optimization becomes neither sustainable nor safe.
Kuckländer, Nina. "Synchronization via correlated noise and automatic control in ecological systems." [S.l.] : [s.n.], 2006. http://opus.kobv.de/ubp/volltexte/2006/1082.
Full textGouhier, Tarik Claude. "Causes and consequences of population fluctuations in spatial ecological systems." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:8881/R/?func=dbin-jump-full&object_id=92227.
Full textSaikaly, Pascal E. "Ecological approach to mitigate toxic shocks in activated sludge systems." Connect to resource online, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1125670988.
Full textKuckländer, Nina. "Synchronization via correlated noise and automatic control in ecological systems." Phd thesis, Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2006/1082/.
Full textThe first part is motivated by field studies on feral sheep populations on two islands of the St. Kilda archipelago, which revealed strong correlations due to environmental noise. For a linear system the population correlation equals the noise correlation (Moran effect). But there exists no systematic examination of the properties of nonlinear maps under the influence of correlated noise. Therefore, in the first part of this thesis the noise-induced correlation of logistic maps is systematically examined. For small noise intensities it can be shown analytically that the correlation of quadratic maps in the fixed-point regime is always smaller than or equal to the noise correlation. In the period-2 regime a Markov model explains qualitatively the main dynamical characteristics. Furthermore, two different mechanisms are introduced which lead to a higher correlation of the systems than the environmental correlation. The new effect of "correlation resonance" is described, i. e. the correlation yields a maximum depending on the noise intensity.
In the second part of the thesis an automatic control method is presented which synchronizes different systems in a robust way. This method is inspired by phase-locked loops and is based on a feedback loop with a differential control scheme, which allows to change the phases of the controlled systems. The effectiveness of the approach is demonstrated for controlled phase synchronization of regular oscillators and foodweb models.
Gegenstand der Arbeit ist die Möglichkeit der Synchronisierung von nichtlinearen Systemen durch korreliertes Rauschen und automatische Kontrolle. Die Arbeit gliedert sich in zwei Teile.
Der erste Teil ist motiviert durch Feldstudien an wilden Schafspopulationen auf zwei Inseln des St. Kilda Archipels, die starke Korrelationen aufgrund von Umwelteinflüssen zeigen. In einem linearen System entspricht die Korrelation der beiden Populationen genau der Rauschkorrelation (Moran-Effekt). Es existiert aber noch keine systematische Untersuchung des Verhaltens nichtlinearer Abbildungen unter dem Einfluss korrelierten Rauschens. Deshalb wird im ersten Teils dieser Arbeit systematisch die rauschinduzierte Korrelation zweier logistischer Abbildungen in den verschiedenen dynamischen Bereichen untersucht. Für kleine Rauschintensitäten wird analytisch gezeigt, dass die Korrelation von quadratischen Abbildungen im Fixpunktbereich immer kleiner oder gleich der Rauschkorrelation ist. Im Periode-2 Bereich beschreibt ein Markov-Modell qualitativ die wichtigsten dynamischen Eigenschaften. Weiterhin werden zwei unterschiedliche Mechanismen vorgestellt, die dazu führen, dass die beiden ungekoppelten Systeme stärker als ihre Umwelt korreliert sein können. Dabei wird der neue Effekt der "correlation resonance" aufgezeigt, d. h. es ergibt sich eine Resonanzkurve der Korrelation in Abbhängkeit von der Rauschstärke.
Im zweiten Teil der Arbeit wird eine automatische Kontroll-Methode präsentiert, die es ermöglicht sehr unterschiedliche Systeme auf robuste Weise in Phase zu synchronisieren. Die Methode ist angelehnt an Phase-locked-Loops und basiert auf einer Rückkopplungsschleife durch einen speziellen Regler, der es erlaubt die Phasen der kontrollierten Systeme zu ändern. Die Effektivität dieser Methode zur Kontrolle der Phasensynchronisierung wird an regulären Oszillatoren und an Nahrungskettenmodellen demonstriert.
Anderies, John M. "Culture, economic structure, and the dynamics of ecological economic systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0004/NQ34506.pdf.
Full textMcGuire, Julia Bayer. "Social ecological food systems| Sustainability lessons from Maine dairy networks." Thesis, The University of Maine, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10300303.
Full textMilk production has played an integral role in the culture, landscape, and economy of Maine's agriculture. Maine dairy farmers have faced numerous sustainability challenges to economic, environmental, and social aspects of their industry. Like many other complex social ecological systems, the Maine dairy industry faces a gap between scientific knowledge and actionable management or policy. A cultural dichotomy exists between conventional and organic farming. Shifting the focus from this binary, metrics such as social capital may play a key role in solving sustainability issues. Difficulties arise in the governance of complex social ecological systems when the scales of assessment, management, and policy do not match principal challenges. Despite efforts by many, Maine dairy challenges may be fueled by a state political system that is restricted by term limits and short legislative sessions. Piecemeal policy-making leads to assessment and policy outcomes that do not take the complexities of the system into consideration.
In the case of the Maine dairy industry, using mental modeling and social network analysis: 1) we seek to explore a method that may improve understanding in cases of disintegration between sustainability policy and action; 2) we test whether social capital, measured using Maine dairy farmers' information networks, spans perceived boundaries between conventional and organic management and between different farm sizes, and; 3) we investigate the scale problemscape for long-term success of the Maine dairy industry.
We found no significant difference in the importance of the economic, environmental, or social factors that dairy farmers considered to be the most challenging to industry sustainability. Social capital, rather than farm management practice or size, is a critical variable for better understanding industry sustainability. We found gaps between the current industry policy structure and the management and assessment scales required to address sustainability challenges. The barriers to effective long-term management, assessment, and policy are numerous for the Maine dairy industry. Our findings suggest that solutions concentrating on only one sustainability factor are unlikely to work in the longterm. Solutions may lie in a more holistic evaluation process, and inclusion of social capital and scale assessments to effectively link science and policy.
AlAdwani, Mohammad S. Kh F. Sh. "Understanding the effects of functional responses in ecological dynamical systems." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121887.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 45-46).
The main purpose of incorporating functional responses into ecological models has been to add more realism and to help us to mechanistically explain the dynamics of species abundances in nature. Yet, their effects have not been widely understood, especially in multispecies systems. That is, it remains unclear whether the perceived benefits of adding functional responses are simply mathematical artefacts or not. For example, while functional responses have been useful to model the dynamics of 2-species systems, still some functional responses have been criticized for producing unrealistic results. Moreover, it has been unclear the extent to which adding functional responses in multispecies systems can allow the dynamics to reach any type of behavior, contrary to the limits that nature may impose. Thus, it is necessary to fully understand the effect of functional responses on ecological models as it is directly linked to their explanatory power of ecological dynamics.
In this Masters thesis, we examine the effect of functional responses in 2-species and multi-species models (or systems). In particular, we examine the number of interior fixed points that are added into dynamical models by introducing functional responses. This number is linked to the capacity of a model to fit data and to the model's sensitivity to perturbation in its parameters. Note that classic ecological models without functional responses have only one interior fixed point regardless of the dimension of the system. We introduce, for the first time, a methodology to count the number of interior fixed points present in a dynamical system with functional responses. In particular, for 2-species models, we uncouple the 2-variable isocline equations (after some manipulations) into two separate single variable equations and examine them. For multispecies models, we compute the mixed volume (number of interior fixed points) of the system's isocline equations (after some manipulation).
We show that incorporating functional responses into 2-species models feeds the system with one or two extra interior fixed points. Importantly, this number increases exponentially in multispecies systems. Hence, we conclude that the explanatory power of multispecies models with functional responses is drastically reduced if model parameters are not ecologically restricted. We believe this work sheds new lights on the applicability of functional responses and opens a new dialogue of what constitutes a realistic model.
by Mohammad S KH F SH AlAdwani.
S.M.
S.M. Massachusetts Institute of Technology, Department of Civil and Environmental Engineering
Hau, Jorge Luis. "Toward environmentally conscious process systems engineering via joint thermodynamic accounting of industrial and ecological systems." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1117650243.
Full textTitle from first page of PDF file. Document formatted into pages; contains xxii, 306 p.; also includes graphics. Includes bibliographical references (p. 290-306). Available online via OhioLINK's ETD Center
Hau, Jorge L. "Toward environmentally conscious process systems engineering via joint thermodynamic accounting of industrial and ecological systems." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1117650243.
Full textÓ, Duibhir Conall. "Simulating Systems : Interactive computer simulations as an educational tool for teaching about social-ecological systems." Thesis, Linnéuniversitetet, Institutionen för kulturvetenskaper (KV), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-105265.
Full textSaikaly, Pascal. "Ecological approach to mitigate toxic shock loads in acivated sludge systems." Cincinnati, Ohio : University of Cincinnati, 2005. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1125670988.
Full textde, la Torre-Castro Maricela. "Humans and Seagrasses in East Africa : A social-ecological systems approach." Doctoral thesis, Stockholm University, Department of Systems Ecology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1061.
Full textThe present study is one of the first attempts to analyze the societal importance of seagrasses (marine flowering plants) from a Natural Resource Management perspective, using a social-ecological systems (SES) approach. The interdisciplinary study takes place in East Africa (Western Indian Ocean, WIO) and includes in-depth studies in Chwaka Bay, Zanzibar, Tanzania. Natural and social sciences methods were used. The results are presented in six articles, showing that seagrass ecosystems are rich in seagrass species (13) and form an important part of the SES within the tropical seascape of the WIO. Seagrasses provide livelihoods opportunities and basic animal protein, in from of seagrass associated fish e.g. Siganidae and Scaridae. Research, management and education initiatives are, however, nearly non-existent. In Chwaka Bay, the goods and ecosystem services associated with the meadows and also appreciated by locals were fishing and collection grounds as well as substrate for seaweed cultivation. Seagrasses are used as medicines and fertilizers and associated with different beliefs and values. Dema (basket trap) fishery showed clear links to seagrass beds and provided the highest gross income per capita of all economic activities. All showing that the meadows provide social-ecological resilience. Drag-net fishery seems to damage the meadows. Two ecological studies show that artisanal seaweed farming of red algae, mainly done by women and pictured as sustainable in the WIO, has a thinning effect on seagrass beds, reduces associated macrofauna, affects sediments, changes fish catch composition and reduces diversity. Furthermore, it has a negative effect on i.a. women’s health. The two last papers are institutional analyses of the human-seagrass relationship. A broad approach was used to analyze regulative, normative and cultural-cognitive institutions. Cooperation and conflict take place between different institutions, interacting with their slow or fast moving characteristics, and are thus fundamental in directing the system into sustainable/unsustainable paths. Ecological knowledge was heterogeneous and situated. Due to the abundance of resources and high internal control, the SES seems to be entangled in a rigidity trap with the risk of falling into a poverty trap. Regulations were found insufficient to understand SES dynamics. “Well” designed organizational structures for management were found insufficient for “good” institutional performance. The dynamics between individuals embedded in different social and cultural structures showed to be crucial. Bwana Dikos, monitoring officials, placed in villages or landing sites in Zanzibar experienced four dilemmas – kinship, loyalty, poverty and control – which decrease efficiency and affect resilience. Mismatches between institutions themselves, and between institutions and cognitive capacities were identified. Some important practical implications are the need to include seagrass meadows in management and educational plans, addressing a seascape perspective, livelihood diversification, subsistence value, impacts, social-ecological resilience, and a broad institutional approach.
Schultz, Lisen. "Nurturing resilience in social-ecological systems : Lessons learned from bridging organizations." Doctoral thesis, Stockholms universitet, Systemekologiska institutionen, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-27503.
Full textMarttila, M. (Maare). "Ecological and social dimensions of restoration success in boreal river systems." Doctoral thesis, Oulun yliopisto, 2017. http://urn.fi/urn:isbn:9789526217253.
Full textTiivistelmä Virtavesien ekologisen tilan heikentyminen on johtanut maailmanlaajuisiin toimiin niiden elinympäristöjen kunnostamiseksi. Usein ekologisen kunnostuksen onnistuminen edellyttää kuitenkin ihmisen ja ympäristön vuorovaikutussuhteiden laaja-alaista ymmärtämistä. Tässä väitöskirjatutkimuksessa käytettiin monitieteistä viitekehystä virtavesikunnostusten ekologisten ja sosiaalisten vaikutusten tutkimiseen. Ensimmäisessä osatyössä arvioitiin kunnostustoimenpiteiden kestävyyttä sekä uoman rakenteellisen monimuotoisuuden kehittymistä pitkällä aikavälillä (10-20 vuotta kunnostusten jälkeen). Toisessa osatyössä tehtiin valtakunnallisen sähkökalastusaineiston avulla meta-analyysipohjainen yhteenveto suomalaisten virtavesikunnostusten vaikutuksista taimenen ja lohen kesänvanhojen (0+) poikasten tiheyteen sekä tutkittiin kunnostustulokseen vaikuttavia ympäristötekijöitä. Kolmannessa osatyössä selvitettiin kunnostusten onnistumista ekosysteemipalvelujen näkökulmasta vertaamalla kahden eri käyttäjäryhmän kokemia muutoksia kolmen tutkimusjoen välillä. Väitöskirjan tulokset osoittivat, että kunnostukset lisäsivät jokiuoman rakenteellista monimuotoisuutta sekä lyhyellä että pitkällä aikavälillä ja vaikuttivat myönteisesti myös biologisiin indikaattoreihin (lohikalojen poikastiheys ja vesisammalet). Vaihtelu pohjan laadussa oli kuitenkin luonnontilaisia uomia vähäisempää ja erityisesti kutuun soveltuvaa soraa oli niukasti. Lohikalojen tiheysvaste vaihteli voimakkaasti jokien välillä, mikä selittyi pääasiassa valuma-alueeseen liittyvillä (esim. valuma-alueen koko ja geologia) ja paikallisilla (mahdollinen lajien välinen kilpailu) tekijöillä. Paikkasidonnaisia eroja havaittiin myös vaikutuksissa ekosysteemipalveluihin ja ne heijastivat etenkin maisemassa ja kalasaaliissa koettuja muutoksia. Tutkimus osoitti, että erilaiset taustat ja odotukset vaikuttavat vahvasti siihen, millaisten kriteerien perusteella kunnostusten onnistumista arvioidaan. Jotta kunnostuksilla saavutettaisiin hyötyjä sekä jokiekosysteemeille että yhteiskunnalle, on tärkeää tuntea paikalliset erityispiirteet ja -tarpeet ja ottaa ne huomioon kunnostuskohteiden valinnassa sekä toimenpiteiden suunnittelussa ja toteutuksessa
Reinke, Diane Carolyn. "A human ecological systems perspective on family violence in Canada's North." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ21203.pdf.
Full textTorre-Castro, Maricela de la. "Humans and seagrasses in East Africa : a social-ecological systems approach /." Stockholm : Department of Systems Ecology, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1061.
Full textCulbertson, Trisha L. "Ecological implications for sustainable stormwater systems in the tallgrass prairie region." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/793.
Full textMcLean, K. M. "Ecological studies on sulphate-reducing bacteria in offshore oil storage systems." Thesis, University of Aberdeen, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377605.
Full textHale, James David. "Elucidating the drivers, contextual sensitivity and resilience of urban ecological systems." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6238/.
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