This dissertation examines nursery/garden centre compliance with Invasive Alien Plant (IAPs) legislation in eThekwini and uMsunduzi, South Africa. Despite South African governmental programmes, an apparent lack of public awareness regarding IAPs persists. The cost to clear IAPs in South Africa is estimated to be 12 billion Rand over 20 years. Nurseries/garden centres should be able to increase customer awareness of IAPs. However, Government regulation/instruction of nurseries/garden centres seems inadequate. A mixed methods approach involving quantitative and qualitative analyses of questionnaires, observations and interviews was used in this study. There was little evidence that nurseries/garden centres stocked/sold CARA plants. However, they were stocking/selling NEMBA plants in spite of knowing CARA, NEMBA and indigenous alternatives. There is little interaction with relevant government/industry programmes. It is recommended that the Department of Environmental Affairs institute a IAPs Advisory Committee to see to the dissemination and provision of relevant information and training concerning IAPs to the industry.

Made available in DSpace on 2016-06-02T19:31:42Z (GMT). No. of bitstreams: 1 2411.pdf: 1852790 bytes, checksum: 59e732f774f4acfec1f2c3148f4d6104 (MD5) Previous issue date: 2009-03-26 / Pittosporum undulatum Vent., an Australian tree implicated in supression of tree recruiment in many ecosystems, is found invading secondary Araucaria forests in subtropical Brazil. The first chapter of this study aimed to investigate the role of allelopathy in the invasive proccess, accessing germination and growth of Bauhinia forficata Link. in presence of secondary metabolites from cheesewood leaves. Leachates in concentrations of 20%, 15%, 10% and 5% (w/v), extracts from dry material (10%; 7,5%; 5% and 2,5%) and coumarin solutions (2,5 mM; 1,25 mM; 0,625 mM and 0,3125 mM) were prepared. Petri-dishes germination bioassays, with countings done at each 12 hours, allowed to determinate both germinabilty and germination rate; polyethylene glicol (PEG 6000) solutions were used to evaluate osmotic effects. For seedlings growth, the three highest concentrations of each solution were tested and after seven days root and shoot lenght were measured. While germinability was only sensitive to extracts from dry material, the germination rate showed a dose-dependent curve for all solutions. In seedlings, roots were the most sensitive structure and severe morfo-anatomic anomalies were observed. The main purpose of the second chapter was to investigate the use of Pittosporum undulatum Vent. (cheesewood) leaves as a possible sustainable alternative for barnyard grass control. Leachates in concentrations of 20%; 15%; 10%; 5% and 2,5% (w/v), aqueous extracts from powdered leachated and non- eachated leaves (10%; 7,5%; 5%; 2,5% and 1,25%), coumarin solutions (2,5 mM; 1,25 mM; 0,625 mM and 0,3125 mM) and Roundup Original® according to label informations were prepared. Polyethylene glycol were also used. Both germinability and germination rate were determined by germination biossays, with countings done at each 12 hours. In growth experiments, seedlings were exposed for seven days, when root and shoot length were measured. All solutions, with exception of coumarins, caused only small inhibitory effects on germination. In relation to the growth, all treatments but control caused necrose, absence of hairs and dose-dependent lenght reduction in radicles. Hipocotiles were affected by phenolic compound, extracts from non-leachated leaves and gliphosate. Although the allelopathic effects, ecophisiological aspects relative to Pittosporum undulatum still need to be cleared before its leaves can be used as a herbicide. / A árvore australiana Pittosporum undulatum Vent. (Pittosporaceae) é encontrada diminuindo o recrutamento de espécies nativas em formações secundárias de Floresta Ombrófila Mista no sul do Brasil. O objetivo do primeiro capítulo desse estudo foi verificar a ação alelopática da espécie no processo invasivo, investigando a sensibilidade de sementes e plântulas de Bauhinia forficata Link. (pata-de-vaca) à compostos foliares de pau-incenso. Foram preparados extratos aquosos lixiviados nas concentrações de 20%, 15%, 10% e 5% (m/v), extratos aquosos obtidos do pó de folhas lixiviadas (10%; 7,5%; 5% e 2,5% ) e soluções de cumarina a 2,5 mM; 1,25 mM; 0,625 mM e 0,3125 mM. Bioensaios em placas de Petri, com contagens realizadas a cada 12 horas, permitiram determinar a germinabilidade e velocidade de germinação; soluções de polietileno glicol (PEG 6000) foram preparadas para analisar os efeitos osmóticos. Nos bioensaios de crescimento, utilizaram-se as três concentrações mais elevadas de cada solução, sendo, após sete dias, medidos o comprimento radicular e de parte aérea. Enquanto a germinabilidade mostrou-se sensível apenas aos extratos de pó de folhas, a velocidade de germinação apresentou resposta dose-dependente para todas as soluções testadas. Quanto ao crescimento, a radícula foi a estrutura mais sensível aos efeitos alelopáticos, sendo observadas alterações morfo-anatômicas. No segundo capitulo, objetivou-se investigar o uso de material foliar de pau-incenso como alternativa ao manejo do capim-arroz, uma gramínea resistente a herbicidas que traz problemas a plantações de arroz e à biodiversidade de planícies úmidas em todo o mundo. Foram preparados extratos aquosos foliares lixiviados nas concentrações de 20%; 15%; 10%; 5% e 2,5% (m/v), extratos aquosos obtidos do pó de folhas lixiviadas e não-lixiviadas (10%; 7,5%; 5%; 2,5% e 1,25%), soluções de cumarina a 5mM; 2,5 mM; 1,25 mM; 0,625 mM e 0,3125 mM e solução de Roundup® Original seguindo as recomendações do fabricante. Soluções de PEG também foram utilizadas. Para bioensaios de germinação, as contagens foram realizadas a cada 12 horas, sendo determinadas as porcentagens e velocidades germinativas; para o crescimento, plântulas de sete dias submetidas aos compostos tiveram medidos seus comprimentos de radícula e parte aérea. A germinação, apesar de fortemente inibida pela cumarina, foi pouco sensível às demais soluções. Quanto ao crescimento, as radículas analisadas apresentaram necrose, ausência de pêlos e redução dose-dependente do comprimento para todos os tratamentos com exceção do controle. Os hipocótilos foram afetados pelo composto fenólico, glifosato e extratos aquosos de folhas não-lixiviadas. Apesar da ação alelopática, aspectos ecofisiológicos relativos ao pau-incenso ainda devem ser esclarecidos para que suas folhas possam ser usadas como herbicida.

Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-10-07T13:06:43Z No. of bitstreams: 1 TeseLALR.pdf: 3856057 bytes, checksum: 10fbc03e49473d6963719567da88bceb (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:05:24Z (GMT) No. of bitstreams: 1 TeseLALR.pdf: 3856057 bytes, checksum: 10fbc03e49473d6963719567da88bceb (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:05:40Z (GMT) No. of bitstreams: 1 TeseLALR.pdf: 3856057 bytes, checksum: 10fbc03e49473d6963719567da88bceb (MD5) / Made available in DSpace on 2016-10-13T20:05:57Z (GMT). No. of bitstreams: 1 TeseLALR.pdf: 3856057 bytes, checksum: 10fbc03e49473d6963719567da88bceb (MD5) Previous issue date: 2016-03-04 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / With the purpose of elucidating some aspects concerning the influence of leaf chemical composition on Chironomidae (Diptera) larvae colonization and their role in decomposition, field experiments were carried out here presented in four chapters: i) Chemical and elemental composition of leaf litter of Hedychium coronarium, Pteridium arachnoideum and Magnolia ovata during decomposition in a low-order stream; ii) Influence of leaf chemical composition in the colonization of Hedychicium coronarium, Pteridium arachnoideum and Magnolia ovata leaf litters by Chironomidae (Diptera) larvae; iii) Feeding habits of the Chironomidae (Diptera) larvae and their contribution to the consumption of plant tissues during decomposition in low order streams; iv) Influence of Chironomidae (Diptera) larvae in the kinetics of aerobic decomposition of Hedychium coronarium, Pteridium arachnoideum and Magnolia ovata leaf litters. The experiments were performed in low order streams in São Carlos-SP and consisted on incubation of polyethylene bottles with small holes containing dried leaves of the three plant species, being removed from time to time over 85 days. Overall, the results indicated that: i) the invader leaf litter showed major quantities of refractory and allelopathic materials than native one; ii) differences in the leaf litter chemical composition influenced the Chironomidae larvae colonization; iii) the chironomids feeding habits differed among plant species and vary with the time of incubation of the leaf litter, amount of remaining mass and adhered organic matter; iv) Chironomidae larvae, mainly shredders, that colonize leaf litters can influence mass loss. / Buscando esclarecimentos sobre a influência da composição química foliar na colonização por larvas de Chironomidae (Diptera) e seu papel na decomposição foram realizados experimentos aqui apresentados em 4 capítulos: i) Composição química de detritos foliares de H. coronarium, P. arachnoideum e M. ovata durante a decomposição em um córrego de baixa ordem; ii) Influência da composição química foliar na colonização de detritos de H. coronarium, P. arachnoideum e M. ovata por larvas de Chironomidae (Diptera); iii) Hábitos alimentares das larvas de Chironomidae (Diptera) e sua contribuição para o consumo de tecidos vegetais durante a decomposição de detritos em riachos de baixa ordem; iv) Influência das larvas de Chironomidae (Diptera) na cinética da decomposição aeróbia de detritos foliares de H. coronarium, P. arachnoideum e M. ovata. Os experimentos foram realizados em riachos tropicais de baixa ordem e consistiram na incubação de frascos de polietileno com pequenos furos contendo folhas desidratadas das três espécies vegetais, sendo retirados parceladamente ao longo de 85 dias. De maneira geral, os resultados indicaram que: i) as plantas invasoras apresentaram maior teor de materiais refratários e alelopáticos do que a nativa; ii) as diferenças na composição química dos detritos influenciaram na colonização pelas larvas de Chironomidae; iii) os hábitos alimentares de quironomídeos diferiram entre as espécies vegetais e variaram com o tempo de incubação dos detritos, quantidade de massa remanescente e matéria orgânica aderida; iv) as larvas de Chironomidae, em especial os fragmentadores, que colonizam os detritos foliares podem influenciar na perda de massa. / FAPESP: 2012/13642-8

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-13T12:34:55Z No. of bitstreams: 1 RafaelLeiteFreire_DISSERT.pdf: 5587232 bytes, checksum: af7254b0e2cbb0b57a16d93d8d90d36e (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-23T16:06:21Z (GMT) No. of bitstreams: 1 RafaelLeiteFreire_DISSERT.pdf: 5587232 bytes, checksum: af7254b0e2cbb0b57a16d93d8d90d36e (MD5) / Made available in DSpace on 2017-01-23T16:06:21Z (GMT). No. of bitstreams: 1 RafaelLeiteFreire_DISSERT.pdf: 5587232 bytes, checksum: af7254b0e2cbb0b57a16d93d8d90d36e (MD5) Previous issue date: 2016-03-28 / Este trabalho tem como objetivo geral compreender as continuidades e descontinuidades hist?ricas na representa??o dos corpos monstruosos/alien?genas no di?logo entre a linguagem televisiva, teatral e cinematogr?fica. Procuro, assim, o entre-lugar que o corpo transversaliza nos espa?os acerca dessas linguagens com base no seriado Jornada nas Estrelas dos anos 1960, no projeto de teatro de rua ?Trek in The Park? (2009-2013), e no filme hom?nimo ao seriado (2009). Nesses tr?s objetos art?sticos-midi?ticos se verificou uma mudan?a na percep??o ao corpo monstruoso. No decorrer da hist?ria, esse corpo foi visto em produ??es art?sticas variadas, como a representa??o do feio, e produtor dos sentidos de medo, constrangimento e riso. No corpus de an?lise pressuponho uma mudan?a ao olhar esses corpos na contemporaneidade, por se tratar de um per?odo no qual se assiste a um maior protagonismo de minorias, a exemplo de gays, negros e mulheres, e ainda maior visibilidade do corpo monstruoso - agora gerador de identifica??o positiva - nos ?mbitos da performance e da cena em geral. Portanto, os objetivos espec?ficos s?o: percorrer historicamente as concep??es de corpo monstruoso, relacionar as concep??es de corpo na contemporaneidade, analisar a produ??o de sentidos e o investimento pol?tico nos corpos alien?genas. Para tanto, o trajeto te?rico-metodol?gico se constitui por meio do movimento interic?nico proposto por Courtine (2013), o qual se refere a imagens que est?o ligadas ? mem?ria interna (lembran?as) e externa (diversas imagens visualizadas). Tal como ao conceito de Dispositivo, de Foucault (1979), entendido como a rede que interliga discursos, institui??es, proposi??es filos?ficas ou morais, enunciados cient?ficos, etc. Assim como o conceito ampliado e atualizado por Agamben (2009). Analiso, pois, dois epis?dios de Jornada nas Estrelas encenados tamb?m pela companhia Teatral ?Trek in the Park: Tempo de Loucura? e ?A Caminho para Babel?, procurando de forma aprofundada debater a respeito do corpo dos Vulcanos e seu gestual. Por fim, concluo o personagem Spock como controverso e com ares de anti-her?i. / This study aims to understand the continuities and discontinuities in the historical representation of the monstrous / alien bodies in the dialogue among the television, theatrical and cinematic language, seeking thus the betweenplace distance that goes along the body in a transversal direction in the spaces between these languages based on the Star Trek television series of the 1960s, the street theater project "Trek In The Park" (2009-2013), and the eponymous to the show, the film of (2009). These three artistic-media objects have been a change in the perception of the monstrous body. Down through history, this body was seen in various artistic productions as representing the ugly and producer of fear of felt, embarrassment and laughter. The analysis corpus presupposes a change to look at these bodies in contemporary times, because it is a period in which we are witnessing a major role of minorities, such as gays, blacks and women, and greater visibility of the monstrous body - now a generator of positive identification - in the areas of performance and the overall scene. Therefore, the specific objectives are: to go historically through the monstrous body of conceptions, to relate the concepts of body in contemporary times, and to analyze the production of senses and political investment in alien bodies. Thus, the theoretical and methodological path is constituted through intericonic movement proposed by Courtine (2013), which refers to images that are linked to the internal memory (memories) and external (various images viewed). As the concept of device, of Foucault (1979), understood as the network that interconnects speeches, institutions, philosophical or moral propositions, scientific statements, etc. As well as the expanded and updated concept by Agamben (2009). Thus, I analyze, two episodes of Star Trek also staged by the Theatre Company "Trek in the Park: Amok Time" and "Journey to Babel", looking in depth to debate about the body of Vulcan and his gestual. Finally, I conclude the character Spock as controversial and with anti-hero characteristics.

It is imperative to understand the strong coupling between the carbon capture process and water use to sustainably manage rangelands. Woody encroachment is undermining rangelands grass production. Evapotranspiration (ET) highlights the links between ecosystem carbon capture process and water use. It forms the biggest flux of the hydrological cycle after precipitation yet it is not well understood. The Grassland and the Albany Thicket (AT) biomes in the Eastern Cape, South Africa, provide an interesting space to study the dynamics in rangelands biomass production and the associated water use. Therefore, the main purpose of this study was to contribute towards management of rangelands by understanding the dynamics in rangeland grass production and water use. To achieve this aim, the impact of Acacia mearnsii, an invasive alien plant, on soil chemical properties and rangelands grass production was investigated. This was achieved by analysing the biophysical attributes of A. mearnsii as they related to grass production. Secondly, selected soil variables that could be used as a prognosis for landscape recovery or deterioration were evaluated. In addition, aboveground grass biomass was measured in areas cleared of A. mearnsii and regression equations were prepared to help model aboveground grass biomass in areas cleared of A. mearnsi. The thesis also explored dynamics in water vapour and energy fluxes in these two biomes using an eddy covariance system. Consequently, water vapour and energy fluxes were evaluated in order to understand landscape water use and energy partitioning in the landscape. The study also tested the application of Penman-Monteith equation based algorithms for estimating ET with micrometeorological techniques used for validation. Pursuant to this, the Penman- Monteith-Leuning (PML) and Penman-Monteith-Palmer (PMP) equations were applied. In addition, some effort was devoted to improving the estimates of ET from the PMP by incorporating a direct soil evaporation component. Finally, the influence of local changes in catchment characteristics on ET was explored through the application of a variant of the Budyko framework and investigating dynamics in the evaporative index as well as applying tests for trends and shifts on ET and rainfall data to detect changes in mean quaternary catchment rainfall and ET. Results revealed that A. mearnsii affected soil chemical properties and impaired grass production in rangelands. Hence, thinning of canopies provided an optimal solution for enhanced landscape water use to sequestrate carbon, provide shade, grazing, and also wood fuel. It was also shown that across sites, ET was water limited since differences between reference ET and actual ET were large. ET was largely sensitive to vapour pressure deficit and surface conductance than to net radiation, indicating that the canopies were strongly coupled with the boundary layer. Rangeland ET was successfully simulated and evaporation from the soil was the dominant flux, hence there is scope for reducing the so-called ‘unproductive’ water use. Further, it was shown that the PML was better able to simulate ET compared to the PMP model as revealed by different model evaluation metrics such as the root mean square error, absolute mean square error and the root mean square observations standard deviation ratio. The incorporation of a soil evaporation component in the PMP model improved estimates of ET as revealed by the root mean square error. The results also indicated that both the catchment parameter (w) and the evaporative index were important in highlighting the impacts of land cover change on ET. It was also shown that, despite changes in the local environment such as catchment characteristics, global forces also affected ET at a local scale. Overall, the study demonstrated that combining remote sensing and ground based observations was important to better understand rangeland grass production and water use dynamics.

Extensive areas of the Eastern Cape Province have been invaded by Pteronia incana (Blue bush), a non-palatable patchy invader shrub that is associated with soil degradation. This study sought to establish the relationship between the invasion and a range of eco-physical and land use gradients. The impact of the invader on soil moisture flux was investigated by comparing soil moisture variations under grass, bare and P. incana invaded surfaces. Field based and laboratory spectroscopy was used to validate P. incana spectral characteristics identified from multi-temporal High Resolution Imagery (HRI). A belt transect was surveyed to gain an understanding of the occurrence of the invasion across land use, isohyetic, geologic, vegetation, pedologic and altitudinal gradients. Soil moisture sensors were calibrated and installed under the respective surfaces in order to determine soil moisture trends over a period of six months. To classify the surfaces using HRI, the pixel and sub-pixel based Perpendicular Vegetation Index (PVI) and Spectral Mixture Analysis (SMA) respectively were used. There was no clear trend established between the underlying geology and P. incana invasion. Land disturbance in general was strongly associated with the invasion, as the endemic zone for the invasion mainly comprised abandoned cultivated and overgrazed land. Isohyetic gradients emerged as the major limiting factor of the invasion; a distinct zone below 619mm of mean annual rainfall was identified as the apparent boundary for the invasion. Low organic matter content identified under invaded areas was attributed to the patchy nature of the invader, leading to loss of the top soil in the bare inter-patch areas. The area covered by grass had consistently higher moisture values than P. incana and bare surfaces. The difference in post-rainfall moisture retention between grass and P. incana surfaces was significant up to about six days, after which a near parallel trend was noticed towards the ensuing rainfall episode. Whereas a higher amount of moisture was recorded on grass, the surface experienced moisture loss faster than the invaded and bare surfaces after each rainfall episode. ii There was consistency in multi-temporal Digital Number (DN) values for the surfaces investigated. The typically low P. incana reflectance in the Near Infrared band, identified from the multi-temporal HRI was validated by field and laboratory spectroscopy. The PVI showed clear spectral separability between all the land surfaces in the respective multi-temporal HRI. The consistence of the PVI with the unmixed surface image fractions from the SMA illustrates that using HRI, the effectiveness of the PVI is not impeded by the mixed pixel problem. Results of the laboratory spectroscopy that validated HRI analyses showed that P. incana’s typically low reflectance is a function of its leaf canopy, as higher proportions of leaves gave a higher reflectance. Future research directions could focus on comparisons between P. incana and typical green vegetation internal leaf structures as potential causes of spectral differences. Collection of spectra for P incana and other invader vegetation types, some of which have similar characteristics, with a view to assembling a spectral library for delineating invaded environments using imagery, is another research direction.

The Working for Water (WfW) Programme is a public works programme designed to clear South Africa of invasive alien vegetation and to restore lowwater consuming indigenous vegetation in the areas that have been cleared. Funds to clear alien invasives were initially secured on the basis that such a programme would increase water runoff, facilitate biodiversity and ecosystem functioning, and provide social benefits through job creation. The economic merits of the Programme, in terms of increased water yields, has been established in the Western Cape and KwaZulu-Natal, but questioned in the Eastern and Southern Cape. However, there are economic aspects of the studies carried out in the Eastern and Southern Cape that merit more attention than was given them; one of these being the issue of non-water benefits. Preliminary figures emanating from contingent valuation pilot studies conducted at six WfW projects sites indicated that one of these non-water benefits, namely the biodiversity and ecosystem resilience benefit, could be substantial. As such, the primary objective of the present study was to apply the contingent valuation method (CVM) to value people’s preference for indigenous vegetation. This value was intended to serve as a proxy for increased biodiversity and ecosystem resilience at three WfW sites. Despite the controversy surrounding the CVM, it has been found that it is a credible valuation tool. The CVM’s merits lie in its versatility and in the fact that it is the only method available which is capable of obtaining estimates of both nonuse and use values, thus making it applicable for valuing biodiversity. The primary aim of a CVM study is to determine an estimate of the total willingness-to-pay (WTP). In this study, the total WTP figure was calculated by multiplying the median WTP for the local WfW Programme by the total number of user households. The respective total WTP amounts are shown in Table 1. It was anticipated that respondents would be willing to pay more for the national WfW Programme, than for the less inclusive good (i.e. the local WfW Programme). The results correspond with this expectation at the Port Elizabeth and Underberg sites. However, due to strategic factors Worcester respondents were willing to pay more for the local WfW Programme than for the national Programme.

This thesis presents two applications of the incompleteness and one application of the imperfection of the market economy. The first application, Chapter 2, studies the decision making problem of an individual seeking to accumulate an optimal amount of human capital realizing that the wage income derived from the accumulated human capital is subject to incompletely insured uncertainty. In other words, the financial market that insures against wage income risk is not fully functional. We find that the individual's inability to diversify wage income risk tends to increase the need to accumulate more human capital in order to elevate wage path and compensate for the burden of its associated risk. This is particularly true when (i) the wage income risk is positively correlated with the rate-of-return risk in the financial market, resulting in an even greater risk burden to the individual, and (ii) the individual is more risk averse. There are two possibilities that no human capital is needed. The first possibility occurs when it is optimal to work as an unskilled worker because both the burden from wage income risk and the rate of return from education are low. The second possibility is the case where the risk burden is so high that the optimal time spent in school to acquire sufficient human capital to cover the risk is so long that the discounted rate of return from education is negative. In this case, the best strategy is to invest in financial assets alone and forfeit the opportunity to earn wage income - either as an educated or as an unskilled worker - to avoid its associated risk. Chapter 3 applies equilibrium unemployment theory with a frictional labor market to study the impact of immigration on the local labor market. Markets are imperfect in the sense that job matching takes time and recruitment is costly. We find that labor market outcomes of both the natives and existing immigrants depend crucially on how the economic surplus from successful matching is divided between the firms and the workers or, in other words, on the bargaining power of the workers. An arrival of immigrants with low bargaining power tends to benefit both the natives and the existing immigrants. A disparity between the two worker types in the matching efficiency also plays a major role. An inferior matching technology among the immigrants, interpreted here as reflecting their less established social network, lowers their wage rate and increases their unemployment rate. The natives are more likely to benefit from additional immigration than the existing immigrants and, when they do, the overall benefit can be decomposed into "job creation spillover" effect resulting from the immigrants' low bargaining power, and "job stealing" effect resulting from the immigrants' less efficient matching. The implications on the pattern of international migration flows are also discussed. In Chapter 4, a simple macroeconomic model is constructed and applied quantitatively to OECD countries, to analyze the effect of incomplete insurance on saving, growth and welfare in a closed economy. In this economy, precautionary saving motivated by uninsured idiosyncratic shocks raises growth rates but lowers risk-free returns. Welfare is measured by the sum of growth rates and risk-free rates of return, not growth rates alone. This welfare measure takes the negative impact of precautionary saving into consideration. Applied to the OECD data, three major results emerge: (i) the heterogeneous performance of growth and saving across the countries reflects different degrees of insurance incompleteness, (ii) since the externality of growth on productivity was very strong in the 1960's, the heavily constrained insurance market itself improves productivity by promoting growth, thereby enhancing welfare, (iii) while the externality of growth became weaker in the 1980's, the development of insurance markets lowered growth, but still contributed to a raise in welfare. / Arts, Faculty of / Vancouver School of Economics / Graduate

This dissertation presents research on the value of using different sources of data to explore the factors determining invasiveness of introduced species. The research draws upon the availability of data on the historical trial plantings of alien species and other sources. The focus of the study is on Australian Acacia species as a taxon introduced into southern Africa (Lesotho, South Africa and Swaziland). The first component of the study focused on understanding the factors determining introduction outcome of species in historical trial plantings and invasion success of Australian Acacia species using Species Distribution Models (SDMs) and classification tree techniques. SDMs were calibrated using the native range occurrence records (Australia) and were validated using results of 150 years of South African government forestry trial planting records and invaded range data from the Southern African Plant Invaders Atlas. To understand factors associated with survival (‘trial success’) or failure to survive (‘trial failure’) of species in historical trial plantings, classification and regression tree analysis was used. The results indicate climate as one of the factors that explains introduction and/or invasion success of Australian Acacia species in southern Africa. However, the results also indicate that for ‘trial failures’ there are factors other than climate that could have influenced the trial outcome. This study emphasizes the need to integrate data on whether the species has been recorded to be invasive elsewhere with climate matching for invasion risk assessment. The second component of the study focused on understanding the distribution patterns of Australian Acacia species that are not known as invasive in southern Africa. The specific aims were to determine which species still exist at previously recorded sites and determine the current invasion status. This was done by collating data from different sources that list species introduced into southern Africa and then conducting revisits. For the purpose of this study, revisits means conducting field surveys based on recorded occurrences of introduced species. The known occurrence data for species on the list were obtained from different data sources and various invasion biology experts. As it was not practical to do revisits for all species on the list, three ornamental species (Acacia floribunda, A. pendula and A. retinodes) were selected as part of the pilot study for the conducted revisits in this study. Acacia retinodes trees were not found during the revisits. The results provided data that could be used to characterize species based on the Blackburn et al., (2011) scheme. However, it is not clear whether observed Acacia pendula or A. floribunda trees will spread away from the sites hence the need to continuously monitor sites for spread. The methods used in this research establish a protocol for future work on conducting revisits at known localities of introduced species to determine their population dynamics and thereby characterize the species according to the scheme for management purposes. / Dissertation (MSc)--University of Pretoria, 2014. / National Research Foundation (NRF) / Zoology and Entomology / MSc (Zoology) / Unrestricted

I arbetet studerades volymtillväxt hos några försök med lärk och deras hybrider i Siljansfors försökspark (SLU). Mätningar gjordes hösten 2021 på ett lärkförsök, anlagt våren 2015. Syftet var att för första gången i Sverige testa och jämföra på en och samma lokal produktionspotentialen hos japansk (Larix kaempferi), europeisk (Larix decidua) och rysk lärk (Larix sukaczewii), samt korsningar mellan dessa i relation till tall (Pinus sylvestris), gran (Picea abies) och contorta (Pinus contorta). Jämförelser gjordes också med mätningar på två tidigare försök på samma försökspark anlagda 1963 och 1965 bestående av rysk- och europeisk lärk, tall, gran, vårtbjörk och glasbjörk, dock inga hybrider. Resultatet från jämförelserna i försök 9297 från 2015 visar att europeisk lärk har den största volymutvecklingen mellan 2015 och 2021.