Orientador: Flavio Antonio Maes dos Santos / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-16T20:45:37Z (GMT). No. of bitstreams: 1 Virillo_CarolinaBernucci_D.pdf: 2082404 bytes, checksum: 73a7c246ad5ac8eccbc8fcf39ee5364b (MD5) Previous issue date: 2010 / Resumo: Os mecanismos responsáveis pela alta diversidade de espécies arbóreas em florestas tropicais têm sido alvo de intenso debate na literatura, e dentre os inúmeros mecanismos propostos, dois deles têm encontrado relativo suporte empírico: a dependência de densidade e a diferenciação de nichos. O objetivo deste trabalho foi investigar a ocorrência destes mecanismos na Floresta Ombrófila Densa Atlântica, que apresenta uma enorme diversidade de espécies vegetais, que variam em abundância, e uma grande diversidade de habitats, o que faz deste bioma um local apropriado para buscar evidências da ocorrência desses mecanismos. Foi investigada a influência da densidade de coespecíficos, da vizinhança e do microhábitat na demografia de quatro espécies arbóreas, e esperava-se que estes fatores atuassem de maneira conjunta na determinação da demografia das espécies estudadas. Em cinco áreas de 0,25 ha, duas na Floresta Ombrófila Densa de Terras Baixas (TB) e três na Floresta Ombrófila Densa Submontana (SM), foram marcados e medidos os indivíduos destas espécies, e um recenso foi realizado após dois anos para obtenção de taxas de mortalidade e recrutamento. Indivíduos com PAP (perímetro a altura do peito) > 15 cm foram acompanhados mensalmente para a avaliação da fenologia reprodutiva e do incremento diamétrico. Foi avaliada a influência da densidade de indivíduos e da distância e número de vizinhos coespecíficos na demografia das espécies. Também foi avaliada a relação da demografia com habitats específicos, dados pela declividade e pela porcentagem de abertura de dossel, assim como da fenologia reprodutiva e do incremento diamétrico com a cota de altitude e com o índice de iluminação da copa (IC). Para nenhuma das espécies estudadas foi encontrada relação entre a densidade total de indivíduos e as taxas de mortalidade e de recrutamento. Entretanto, nas áreas de maior abundância, foram encontradas associações entre os indivíduos mortos e os demais indivíduos da população, assim como diminuição da agregação conforme se considera classes de tamanho maiores, que podem ser interpretadas como evidências dos processos dependentes de densidade, indicando que os processos dependentes de distância ou densidade só se mostram importantes em situações de densidade elevada. Houve relação do número de indivíduos com a declividade para a maioria das espécies, mas foram poucas as relações significativas com a abertura de dossel. A mortalidade, o recrutamento e o crescimento dos indivíduos com PAP < 15 cm apresentaram poucas relações significativas com as variáveis ambientais (IDP e abertura do dossel), provavelmente devido ao baixo número de eventos registrados. Para duas das espécies, a fenologia reprodutiva se relacionou com a cota de altitude, mas não com o IC, indicando um aspecto da preferência de hábitat. Já o incremento diamétrico variou muito dentro de uma mesma cota altitudinal, se relacionando, para duas das espécies, com o IC, mas para as outras duas espécies nem a altitude e nem a iluminação das suas copas explicou a variação observada no crescimento. Recomenda-se que um maior número de variáveis ambientais sejam utilizadas para caracterizar os microambientes quando se busca evidências de preferências de hábitat. É provável que os mecanismos estudados não sejam mutuamente exclusivos e que eles atuem em conjunto na determinação dos processos demográficos populacionais, e assim influenciando conjuntamente na manutenção da grande diversidade de espécies arbóreas em florestas tropicais. / Abstract: The mechanisms that are responsible for the high tree species diversity in tropical forests have been intensively debated on literature, and among the several proposed mechanisms, two of them have been relatively empirically supported: the density-dependence and the niche differentiation. The aim of this work was to investigate the occurrence of these mechanisms on the Atlantic Ombrophilous Dense Forest, that has a huge plant species diversity, that vary on their abundance, and a high diversity of habitats, what makes this biome an appropriate place to seek for the existence of these mechanisms. We investigated the influence of conspecific density, neighborhood and microhabitat on the demography of four tree species, and we expected these factors to act together on determining the demography of the studied species. On five 0.25 ha area, two on the Lowland Ombrophilous Dense Forest and three on the Lower-montane Ombrophilous Dense Forest, we tagged and measured all the plants of the studied species; the plants were re-censused after two years so we obtained the mortality and recruitment rates. Plants with perimeter at breast height (PBH) > 15 cm were monthly observed to evaluate their reproductive phenology and diameter increment. We evaluated the influence of the density of plants and the number and distance of conspecific neighbors on the demography of the studied species. We also evaluated the relationship of the demographic rates with specific habitats, given by canopy openness and declivity, and of the reproductive phenology and diameter increment with the altitude and the crown illumination index (IC). We found no relationship between the total density of individuals and the mortality or recruitment rates, but on the areas of high abundance we found associations between the dead plants and the other plants of the populations, as well as lower aggregation as we considered bigger size classes, which could be interpreted as evidences of the density dependent processes, indicating that the density or distance-dependent processes are important only on high density situations. We found significant relationships between the number of individuals and declivity for the majority of species, but there were few significant associations with the canopy openness. Mortality, growth and recruitment of plants PBH < 15 cm have few significant correlations with environmental variables (declivity and canopy openness), probably because of the low number of events registered. For two of the studied species, the reproductive phenology was related to the altitude but not with IC, indicating one aspect of the habitat preference. The diameter increment showed great variation on the same altitude, and for two species it was related with IC, but for the other two neither the altitude nor the IC explained the observed variation on growth. We recommend the use of more environmental variables to characterize the microenvironments when seeking for evidence of habitat preference. It's possible that the studied mechanisms are not mutually exclusive and that they act together on determining the demographic processes, and so, influencing together the maintenance of the high tree species diversity on tropical forests. / Doutorado / Mestre em Biologia Vegetal

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-10-29T10:05:37Z No. of bitstreams: 2 Dissertação - Leonardo Barros de Macedo - 2012.pdf: 639690 bytes, checksum: 4360ea45fb11a0ae3bac9bc2ce2974ea (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2014-10-30T10:18:59Z (GMT) No. of bitstreams: 2 Dissertação - Leonardo Barros de Macedo - 2012.pdf: 639690 bytes, checksum: 4360ea45fb11a0ae3bac9bc2ce2974ea (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-30T10:18:59Z (GMT). No. of bitstreams: 2 Dissertação - Leonardo Barros de Macedo - 2012.pdf: 639690 bytes, checksum: 4360ea45fb11a0ae3bac9bc2ce2974ea (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2012-08-17 / Soybean (Glycine max L.) is now a major export products from Brazil and one of the main commodities in the world. In the Central West region of Brazil, the main soybean-producing region, the lesion nematode, Pratylenchus brachyurus, has become a major problem for culture can lead to significant losses. Weeds are also a limiting factor for obtaining high yields in soybean, and herbicide application to control it can affect the population of nematodes. This study aimed to evaluate the effect of herbicides, including glyphosate, on the population density of P. brachyurus on soybean conventional and transgenic cultivar. Two experiments were conducted in field conditions and another in a greenhouse in 2010/2011 harvest. The experimental design of the first was completely randomized in factorial arrangement 2x4+2, with four replicates. In greenhouse the design was completely randomized, with the same factorial design and six replications. The factors of the treatments consisted of cultivars, with two levels (BRSGO Iara and M-SOY 8001), and methods of weed control, with four levels (pull-off manual and chemical control with lactofen, chlorimuron-ethyl, and haloxifop-r). Two additional treatments consisted of transgenic cultivar BRS Valiosa RR with manual control of weeds and glyphosate. The assessments for the population of P. brachyurus, in the field were made at 45 and 90 days after emergence (DAE). We also evaluated the biomass, leaf area index (LAI), fresh and dry mass of pods. In the greenhouse were measured wet weight of roots and aboveground biomass at 30 and 60 DAI. The reproduction factor (RF) was determined in both trials. In the field, to calculate the RF was considered the population of nematodes 45 DAE as initial population. The use of transgenic cultivar and glyphosate did not affect the population density of P. brachyurus. There was no difference in the behavior of cultivars in relation to nematode P. brachyurus. Herbicides clorimuron, lactofen and haloxifop also did not affect the population of P. brachyurus. However clorimuron and lactofen reduced the growing of soybean cultivars BRS Iara and M-SOY 8001. / A soja (Glycine max L.) é hoje um dos principais produtos de exportação do Brasil e uma das principais commodities do mundo. Na região Centro Oeste do Brasil, a principal região produtora de soja, o nematoide das lesões radiculares, Pratylenchus brachyurus, tornou-se um grande problema para a cultura, podendo ocasionar importantes perdas. As plantas daninhas também constituem fator limitante para a obtenção de altos rendimentos na cultura da soja, e a aplicação de herbicidas para o seu controle pode afetar a população de nematoides. O presente trabalho teve como objetivo avaliar o efeito de herbicidas, incluindo glyphosate, sobre a densidade populacional de P. brachyurus, em cultivares de soja convencionais e uma cultivar transgênica. Foram conduzidos dois ensaios, um em campo e outro em casa de vegetação, na safra 2010/2011. O delineamento experimental utilizado no campo foi blocos casualizados, em arranjo fatorial 2x4+2, com quatro repetições. Em casa de vegetação foi utilizado inteiramente casualizado, com o mesmo esquema fatorial, e seis repetições. Os fatores dos tratamentos consistiram em: cultivares, com dois níveis (BRSGO Iara e M-Soy 8001) e métodos de controle das plantas daninhas, com quatro níveis: arranquio manual e controle químico com lactofen, chlorimuron-ethyl e haloxifop-r. Os dois tratamentos adicionais consistiram da cultivar transgênica BRS Valiosa RR, com controle manual de plantas daninhas e glyphosate. As avaliações para a população de P. brachyurus, no campo, foram efetuadas aos 45 e 90 dias após emergência (DAE). Também avaliaram-se biomassa, índice de área foliar (IAF), massa fresca e massa seca das vagens. Em casa de vegetação foram avaliados o peso fresco de raízes e a biomassa da parte aérea, aos 30 e 60 dias após a inoculação (DAI). O fator de reprodução (FR) foi determinado em ambos os ensaios. No campo, para cálculo do FR considerou-se a população do nematoide aos 45 DAE como população inicial. O uso da cultivar transgênica e do herbicida glyphosate não afetou a densidade populacional de P. brachyurus. Não houve diferença no comportamento das cultivares em relação ao nematoide P. brachyurus. Os herbicidas clorimuron, lactofen e haloxifop também não influenciaram a população de P. brachyurus. Entretanto, clorimuron e lactofen reduziram o crescimento vegetativo das cultivares de soja BRSGO Iara e M-Soy 8001.

Made available in DSpace on 2016-02-26T14:53:15Z (GMT). No. of bitstreams: 1 MarcelaMarcelinoDuarte.pdf: 1274052 bytes, checksum: b5ce76c20accecbe1f4d7eaa128750c6 (MD5) Previous issue date: 2009-03-13 / The aims of this work were to evaluate the effect of different population levels of the green belly stink bug D. melacanthus on corn and wheat plants and also to estimate the damage level of this pest for both crops. The experiments were carried out in an experimental area of Embrapa Western Region Agriculture in Dourados, Mato Grosso do Sul State. Corn was sown in February 2006 and wheat in May 2007. In the corn trial, experimental units were iron cages of 1 m length, 0.9 m width and 0.9 m height that had five corn plants. In the wheat trial, the experimental unit was a wood cage with 160 plants distributed in three rows of 1.12m length and 0.2 m between them. At the moment when the wheat plants showed three leaves they were submitted to different infestation levels of D. melacanthus (0, 2, 4, 6, and 8 bugs/cage) for a period of 15 days. In the corn trial, plants were submitted to the same infestation levels at the moment when showed one leaf (V1) and the period of infestation was 10 days. For both experiments, the experimental design was a completely randomized block with five replicates. Experiments were carried out until harvest and the following measurements were done: number of corn grains row in the ears, ear weight, weight of 100 corn seeds, corn grain yield, ear number, weight of 100 wheat seeds and wheat grain yield. All these measurements were submitted to variance analysis and averages compared by Tukey test at 5%. For determination of the economic threshold level of this pest for both crops, grain yield data were submitted to regression analysis. The cost to control the stink bug on corn and wheat crops was considered in the calculation of the damage level. For the corn crop, number of corn grains row in the ears and the weight of 100 seeds were not significantly influenced by different population densities of the stink bug. For wheat, ear number and the weight of 100 seeds were not significantly different for the different infestation levels of the stink bug. The economic threshold levels were 0.58 and 1 bug/m2 for corn and wheat crops, respectively / O objetivo desse trabalho foi de avaliar o efeito de diferentes níveis populacionais do percevejo barriga-verde Dichelops melacanthus nas plantas de milho e de trigo, visando estimar o Nível de Dano (ND) dessa praga para essas culturas. Os experimentos foram conduzidos em campo na área experimental da Embrapa Agropecuária Oeste em Dourados, MS. O milho foi semeado em fevereiro de 2006 e o trigo em maio de 2007. No ensaio com milho, as unidades experimentais consistiram de uma gaiola em armação de ferro de 1,0 m de comprimento por 0,90 m de largura e 0,90 m de altura, a qual continha cinco plantas de milho. No ensaio com trigo a unidades experimentais consistiram de uma gaiola de madeira que abrangia 160 plantas distribuídas em três fileiras, espaçadas de 0,20 m por 1,12 m de comprimento. Quando as plantas de trigo apresentaram três folhas estas foram submetidas a diferentes níveis populacionais de D. melacanthus (0, 2, 4, 6 e 8 percevejos/gaiola) por um período de infestação de 15 dias. No ensaio de milho, quando as plantas apresentavam uma folha (V1), foram submetidas aos mesmos níveis populacionais do percevejo utilizados no experimento de trigo durante um período de infestação de 10 dias. Ambos os ensaios foram conduzidos no delineamento de blocos casualizados com cinco repetições. Os experimentos foram conduzidos até a colheita para determinação das seguintes variáveis: número de fileiras de grãos nas espigas, peso da espiga, peso de cem sementes e rendimento de grãos do milho e número de espigas, peso de cem sementes e rendimento de grãos do trigo, sendo estas os dados obtidos submetidos à análise de variância e as médias dos tratamentos comparadas pelo teste de Tukey a 5% de significância. Para determinação do NDE da praga nas duas culturas, os valores de rendimento de grãos foram submetidos à análise de regressão. Para o cálculo do nível de dano considerou-se o custo de controle do percevejo na cultura do milho e do trigo. No milho os valores de número de fileiras de grãos por espiga e o peso de cem sementes não foram significativamente influenciados pelas diferentes densidades populacionais do percevejo. No trigo o número de espigas e peso de cem sementes não diferiram estatisticamente entre as diferentes densidades populacionais do percevejo. O NDE encontrado para a cultura do milho foi de 0,58 percevejo/m² e para a cultura do trigo ficou em torno de 1,0 percevejo/m²

The densification of cities in Sweden often result in loss of green space and puts the beneficial values of urban green space under risk. Especially affected are the inhabitants residing in the city core. Through a qualitative case study of Sundbyberg city, this study aims to explore which features of green spaces that becomes important for residents in a city undergoing fast densification. As well as how the needs are answered from a planning perspective. In order to illustrate both perspectives, the study consists of interviews with planners and residents. The results of the study show that the few green spaces in the city core in large have been compensated with small spaces working as multifunctional places. One example of a multifunctional place is a pocket park. This, planners and residents show both a positive and negative view on. The benefits are simply about that it is needed. The disadvantages raised are mainly about the feelings of those places as private and closed space for some people, although these places origins as open space. The study shows that many similarities prevail between the planners and residents views on the different importance’s of the city’s green spaces. It also shows that there is a discrepancy between the residents experienced needs of green spaces and the planner’s vision of the citys future development. While the residents seem to want more quiet places and places for spontaneous activities, especially to meet the needs of elderly and young. The planner’s visions of the citys development seem to go more towards creating small, to some extent green, safe places which connects different parts of the city.

This thesis deals with the influence of population density on the growth of brown trout Salmo trutta. The research was carried out in the Šumava National Park in the river basins of two oligotrophic streams, the Vydra and the Křemelná. Data has been collected between years 2005 and 2010, every spring and autumn. Fish were caught via electrofishing and the length and weight of each individual were measured. Every individual caught was marked in a unique way. A few samples of scales were taken from some of them. The scales were fixed into laboratory slides, scanned and measured by graphic software. According to the differences between annual lamellas density, the age and the annual growth of individual's body length were estimated. Thanks to these results a negative relationship between the individuals' of age 1+ growth rate and the population density was confirmed. The importance of this thesis is mainly in comparing the influence of different spatial and time definitions of population on this relationship. The influence of the population density in spring (the initial time of the growth period) was proved to be essential for the growth rate. This fact suggests the importance of compensation growth intensity after the long period of winter for individual's general growth under conditions provided by...

Water quality is an essential component of vibrant societies and ecosystems. For decades, researchers, managers, and policymakers around the world have struggled to accelerate societal progress while preserving and enhancing water quality and human health. This thesis consists of two studies that I hope will contribute to better understanding, policy, and management. In the first study, I evaluated spatial and temporal patterns in global water quality and their relationship to gross domestic product (GDP) per capita, as a metric of socioeconomic development status. Using global water quality datasets containing over 2.7 million observations, I tested the Environmental Kuznet Curve (EKC) hypothesis, which predicts that environmental degradation is highest at intermediate levels of socioeconomic development. I found that 46% of pollutants persisted at elevated concentrations despite GDP per capita. Because of this, high income countries experience a false sense of water security as water regulation violations are common on a global scale. In the second study, I measured waterborne pathogens in Guayaquil, the largest city in Ecuador. With a population of over 3 million and distinct hydrology from monsoonal rains and estuarine flooding, the Guayaquil metropolitan area faces drinking water and sanitation challenges similar to much of the developing world. I found that 100% of the samples we collected had unsafe total coliform counts. Water pollution is widespread and is a result of careless action. Moving forward, chronic pollution can be prevented with proper legislation that holds governments, companies, and individuals accountable.

No description available.

Thesis (PhD)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The tuberculosis (TB) incidence has increased in Southern Africa and the situation is worsened by the emergence of drug-resistant Mycobacterium tuberculosis strains. Molecular biological techniques have been used to understand the disease dynamics of TB. In a series of studies we describe the use of these techniques to understand the disease dynamics of TB in Southern Africa. Using spoligotyping and IS6110-restriction fragment length polymorphism (RFLP) to characterize M. tuberculosis strains from TB patients in Zimbabwe, we identified a genotype causing a disproportionate number of TB cases. The genotype belonged to the Latin American Mediterranean (LAM) lineage and we named it the Southern Africa1 (SAF1) family and later renamed it SAF1/RDRio, also reflecting its predominance in South America. To establish if this family of strains was predominant elsewhere in Southern Africa, genotypes were compared to those from Western Cape, South Africa and Zambia. The SAF1/RDRio strains were highly prevalent in Zambia but were only a minor fraction of the strains in South Africa. The geographical distribution of SAF1/RDRio strains was determined in Gweru, Zimbabwe, and was found to be spread in high incidence areas. From these two studies it was hypothesized that certain host and bacterial factors were associated with disease due to SAF1/RDRio. Subsequently potential risk factors and clinical outcomes of disease due to SAF1/RDRio strains were explored. An association was found with smoking and cavitary pulmonary disease suggesting that SAF1/RDRio caused a more severe and highly transmissible formof TB Using IS6110-RFLP, principal genetic grouping, spoligotyping, IS6110 insertion-site mapping and variable-number tandem repeats (VNTR) typing, low IS6110 copy clade (LCC) identified in Zimbabwe were characterized and compared to the strains from Cape Town, South Africa and other regions. The LCC strains from Cape Town, South Africa, were found to have close evolutionary relationship with strains from Zimbabwe and other regions and were widely distributed suggesting they play an important role in the global TB epidemic. Observations from these studies and those from other studies led to the hypothesis that specific genotypes of M. tuberculosis predominate in regions of Southern Africa. To gain an insight on the population structure of M. tuberculosis strains in Southern Africa, spoligotyping and/or IS6110-RFLP data from eight countries were compared. This is the first study to describe the M. tuberculosis population structure in Southern Africa. Distinct genotypes were associated with specific geographic regions. These findings have important implications for TB diagnostics, anti-TB drug and vaccine development. The population structure of multidrug-resistant (MDR), pre-extensively drug-resistant (pre-XDR) and extensively drug-resistant (XDR) M. tuberculosis isolates from provinces in South Africa was also determined. This is again the first study to describe the population structure of drug-resistant M. tuberculosis in South Africa. The results also showed geographic localization of genotypes and an association with resistance class. However, decreasing strain diversity was observed as the isolates evolved from MDR-TB to XDR-TB suggesting selection for the specific genotypes. These findings highlight the importance of identifying genetic markers in drug-resistant strains, to enhance early detection of those at risk of developing XDR-TB. / AFIKAANSE OPSOMMING: Die voorkoms van tuberkulose (TB) in Suider Afrika word vererger deur stamme van Mycobacterium tuberculosis wat weerstandig is teen die beskikbare anti-tuberkulose middels. Molekulêre tegnieke word gebruik om in hierdie reeks studies die dinamika van TB in Suider Afrika te ondersoek Deur spoligotipering en IS6110 restriksie fragment lengte polimorfisme (RFLP) tegnieke te gebruik om M. tuberculosis stamme van pasiente in Zimbabwe te beskryf, het ons ‘n genotipe gevind wat ‘n buitengewone aantal TB gevalle veroorsaak het. Hierdie genotipe is deel van die internasionaal beskryfde Latyns Amerikaase en Meditereense (LAM) stam familie. Ons het dit die Suider Afrikaanse Familie1 (SAF1) genoem, maar later hernoem na SAF1/RDRio, omdat dieselfde genotipe in ook volop is in Suid Amerika. Om vas te stel of hierdie familie ook oorheesend is in die res van Suider Afrika, is dit vergelyk met beskikbare databasisse van die Wes-Kaap, Suid-Afrika en Zambië. Alhoewel SAF1/RDRio in die Wes-Kaap gevind is, dra dit slegs tot ‘n mindere mate by tot die plaaslike TB epidemie. Aan die anderkant kom SAF1/RDRio baie algemeen in Zambië voor. ‘n Verdere studie wys ook dat die SAF1/RDRio familie eweredig en wyd verspreid voorkom in hoë insidensie gebiede in Gweru, Zimbabwe. Vanuit die bevindings van hierdie 2 studies, kan ons aflei dat sekere gasheer- en bakteriële eienskappe geassosieer is met SAF1/RDRio-TB-infeksie. Hierna is potensiële risiko faktore en kliniese uitkomste van siekte as gevolg van infeksie met SAF1/RDRio ondersoek. ‘n Assosiasie met rook en kaviterende pulmonale infeksie is gevind,wat daarop dui dat SAF1/RDRio erger vorm van TB veroorsaak en hoogs oordraagbaar is. Deur gebruik te maak van IS6110- (RFLP), hoof groep groepering, spoligotipering, IS6110 invoegings kaartering en veranderlike getal tandem herhaling (VNTR) tipering kon lae IS6110 invoeginsgetal (LCC) stamme van Kaapstad, Zimbabwe en ander gebiede vergelyk word. Al die LCC stamme in die studie is evolusionêr naby verwant aan mekaar en is wyd verspreid, wat dui op hulle belangrike rol in die wêreldwye TB epidemie. Waarnemings in hierdie asook ander studies het tot die hipotese gely dat spesifieke genotipes van M. tuberculosis dominant is in verskillende gebiede van Suider Afrika. Om meer insig tot die populasie samestelling van M. tuberculosis stamme in Suider Afrika in te win is spoligotipes en RFLP-data van 8 lande vergelyk. Hierdie is die eerste studie om die populasie samestelling van M. tuberculosis in Suider Afrika te beskryf en is belangrike fir toekomstige ontwikkeling van nuwe TB diagnose tegnieke, anti-TB middels en TB entstowwe. Die populasie samestelling van multiweerstandige (MDR), pre-ekstreme weerstandige (pre-XDR) en ekstreme weerstandige (XDR) M. tuberculosis van verskillende provinsies in Suid-Afrika is ook bepaal. Hierdie studie is ook die eerste wat die populasie samestelling van weerstandige M. tuberculosis in Suid-Afrika beskryf. Die resultate wys geografiese lokalisering van genotipes en ‘n assosiasie met weerstandigheidsklas. ‘n Afname in stam diversiteit soos die isolate van MDR-TB tot XDR-TB ontwikkel, dui op seleksie van spesifieke genotipes. Hierdie bevinding lê die klem op die belangrikheid van die identifisering van genetiese merkers in weerstandige stamme om die risiko vir die ontwikkeling van XDR-TB te verminder deur vroë deteksie.

As the biomass of jellyfish (medusae of the Scyphozoa and Hydrozoa) has risen in numerous locations worldwide, awareness of their potential to exert a controlling influence on marine ecosystems and hinder the recruitment of fish stocks has increased. Medusae are capable of intensive, size–selective, predation on zooplankton, which may alter the composition of the plankton community. Jellyfish are often found in dense layers, up to hundreds of metres thick, which can extend horizontally for hundreds of kilometres. Such aggregations may benefit specialist feeders, such as turtles, that rely upon jellyfish for food and those fish that are able to find refuge under the jellyfish umbrellas. Nonetheless, the predominance of jellyfish in pelagic ecosystems is not generally viewed as desirable; in fact, this situation has been portrayed as the result of pollution and overexploitation of otherwise productive seas. However, jellyfish are sensitive indicators of environmental change, and their populations appear to respond to climatic fluctuations, so jellyfish warrant study for their intrinsic ecosystem role particularly given present concerns over climate change. With growing acceptance that fishery management should take an holistic ‘ecosystem approach’, knowledge of the interactions between jellyfish, fisheries and climate may be vital in progression towards the goal of ecosystem–based sustainable management of fisheries. Unfortunately, due to their gelatinous nature, medusae are difficult to sample using conventional netting techniques and data on changes in distribution and abundance are consequently sparse. Recent studies have demonstrated that medusae can be detected acoustically and that this technique could provide a rapid and cost–effective estimate of their biomass and distribution. This thesis reports my endeavour to demonstrate the ecosystem role of medusae and to develop acoustic techniques to monitor their biomass. Through regession analyses, I link the abundance of medusae (Aurelia aurita, Cyanea lamarckii, and Cyanea capillata) in regions of the North Sea to climatic fluctuations, as quantified by the North Atlantic Oscillation Index, and show that medusae may be important indicators of regional ecosystem change. The mechanisms linking climatic fluctuations to ecosystem changes are explored via a correlative modelling approach using General Additive Models; I show that the mechanisms are location dependent and explainable in terms of direct, rapidly responding (intra–annual) influences (surface warming, river run–off, and wind–driven mixing and advection) and longer–term (interannual) oceanographic responses (changes in circulation currents i.e. the northward extent of the gulf stream and relative strength of inflow into the North Sea of the North Atlantic current, Continental Shelf Jet and Arctic waters). I present correlative evidence for a detrimental impact by Aurelia aurita on herring 0–group recruitment, once the influence of interannual change in herring spewing stock biomass on recruitment is factored out through modelling with a Ricker stock–recruitment relationship. Similarly, a commensal relationship between whiting and Cyanea spp. medusae is shown to improve North Sea whiting survival to the 1–group. In progress towards the automated acoustic identification of species, I have developed an in situ discrimination tool that can distinguish between echoes from: Aequorea aequorea; Chrysaora hysoscella; clupeid fish (sardine, anchovy and round herring); and horse mackerel/Cape hake. The technique relies upon characteristic differences in echo strength between frequencies, which are determined for each jellyfish species and finfish group using combined multifrequency acoustic and pelagic trawl samples. This method has facilitated the world’s first acoustic–based estimate of jellyfish biomass in the Namibian Benguela Sea. The 12.2 million tonnes of biomass of medusae (Aequorea aequorea and Chrysaora hysoscella) in the Namibian Benguela Sea was found to be greater than the combined biomass, 3.6 million tonnes, of commercially important fish (horse mackerel, Cape hake, sardines, anchovy, and round herring) in the same area. These results suggest that medusae may have an important role in the Benguela ecosystem that has previously been overlooked and that their biomass should be monitored.

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning