<p dir="ltr">Water scarcity and acute drought continue to be serious concerns, even in humid climates where precipitation normally exceeds evapotranspiration (ET), highlighting the need for improved landscape water conservation practices. Lawns represent the largest area in most managed landscapes and require regular mowing, feeding and sometimes supplemental summer irrigation to persist. A general historical guideline for lawn irrigation is to supply 25-38 mm per growing wk-1 in the absence of rainfall. This fixed volume is often applied on a programmatic “set and forget” three times per week schedule (e.g. M-W-F). This application guideline often results in excess irrigation as it does not take into account plant need or prevailing environmental conditions. Further, in times of acute summer drought policymakers may restrict irrigation to once or twice weekly to conserve water. The effects of these regulations on turf health and potential water savings are unclear. Thus, two multi-year summer field studies were conducted to identify opportunities for improved lawn water conservation. Study one evaluated the effect of varying weekly irrigation volume and frequency on mature Kentucky bluegrass (Poa pratensis L.:KBG) located under a fixed-roof rainout structure. Turfgrass response was measured as visual turf quality (TQ), digital green color (DGC), volumetric soil water content (VWC) and area under the curve for each response variable. In year one, KBG was subject to six irrigation programs and compared to a high deficit control for 49 days. The programs were: 25 mm total water wk-1 applied either three times (M-W-F) or twice (M and F) weekly, 19 mm total wk-1 twice weekly (M and F), 13 mm total wk-1 once weekly and 60 or 80% accumulated ETo three times weekly. Due to poor performance, the high deficit control and 60% ETo were excluded from further evaluation. In year two, seven programs were evaluated: 33 mm total water wk-1 applied once, twice, or three times weekly, or every-other-day, 25 mm total wk-1 applied twice or three times weekly and 80% ETo twice weekly for 63 days. In both years, generally, 25-33 mm wk-1 applied two or three times wk-1 produced the most consistent TQ, DGC and highest VWC. Study two compared three supplemental irrigation programs to a natural rainfall control for six widely planted cool-season lawn grasses for 70 days. The six lawn grasses were: a KBG sod, seeded drought tolerant and susceptible KBG cultivars, a turf-type tall fescue (Schedonorus arundinaceus (Schreb.) Durmort.: TTTF) blend and two KBG and perennial ryegrass (Lolium perenne L.:PRG) mixtures. In Study two, highly significant differences p < .001 occurred for irrigation program and lawn grasses. While supplemental irrigation aided all grasses, rainfall in year one and two measured 119 mm and 343 mm, respectively, affecting data in each study year. Area under the turfgrass quality curve (AUTQC) was lowest for the rainfall control (339 and 425) and highest for 33 mm wk-1 applied three times (507 and 526) and 80% ETo programs (508 and 535) in year one and two, respectively. Annual responses for DGC and VWC generally followed TQ trends. For grasses subject only to natural rainfall, TTTF, and the KBGs were generally superior to the KBG:PRG mixtures, thus emphasizing the importance of species selection. In summary, these studies compared a traditional “set and forget” irrigation program to a range of alternative programs and different lawn grasses. These data provide evidence for irrigation savings by employing a combination of planting drought tolerant lawn species and adopting a more limited irrigation program. Future field studies should include the evaluation of adaptive, data-driven programs based on forecast environmental conditions and threshold responses like DGC or predetermined VWC set points calibrated for varying soil types and growing environments.</p>

This thesis choreographs the procession around and within a tower. An alternating sequence of compression and expansion of space creates a rich spatial experience. Each moment along the sequence is meant to complement or contrast the others, exaggerating their effect. The tower's form is designed by producing and then selecting from a series of potential solutions. Each iteration is guided by the aforementioned sequence of spatial conditions. / Master of Architecture

A greater than 10-fold increase in Canada goose (Branta canadensis) populations over the past several years has resulted in concerns over grazing impacts on grass seed production in the mid-Willamette Valley, Oregon. This study was designed to develop methods to quantify and statistically analyze goose-grazing impacts on seed yields of tall fescue (Festuca arundinacea Schreb.) and perennial ryegrass (Lolium perenne L.). Yield-mapping-system equipped combines, incorporating global positioning system (GPS) technology, were used to measure and map yields. Image processing of ground-level photography to estimate crop cover and other relevant observations were spatially located via GPS to establish spatial-temporal goose grazing patterns. We sampled each field semi-monthly from mid-winter through spring. Spatially located yield data, soils information, exclosure locations, and grazing patterns were integrated via geographical information system (GIS) technology. To avoid concerns about autocorrelation, a bootstrapping procedure for subsampling spatially contiguous seed yield data was used to organize the data for appropriate use of analysis of variance. The procedure was used to evaluate grazing impacts on seed yield for areas of fields with different soils and with differential timing and intensity of goose grazing activity. We also used a standard paired-plot procedure, involving exclosures and associated plots available for grazing. The combination of spatially explicit photography and yield mapping, integrated with GIS, proved effective in establishing cause-and-effect relationships between goose grazing and seed yield differences. Exclosures were essential for providing nongrazed controls. Both statistical approaches were effective in documenting goose-grazing impacts. Paired-plots were restricted by small size and few numbers and did not capture grazing impacts as effectively as comparison of larger areas to exclosures. Bootstrapping to subsample larger areas of yield for comparison was an effective method of avoiding autocorrelation of data while better representing impacts within a field. Occasional yield increases, ranging from 1 to 5 percent, were recorded following goose grazing. Goose grazing generally resulted in seed yield reductions, ranging up to 20 percent. Later and more intensive grazing tended to increase yield reductions. Newly seeded tall fescue tended to be the most sensitive to grazing. Established perennial ryegrass tended to be more resilient. / Graduation date: 2003

Les immeubles de grande hauteur (IGH) sont des constructions symboliques liées, le plus souvent, aux problématiques de la rareté du foncier, aux défis de la densification urbaine dans les grandes villes et aussi au questionnement de la construction durable. Pourtant, un IGH ne se limite pas seulement à ces seuls points :quel impact en terme de risque représente un IGH sur son environnement ?Quelle démarche d'analyse d'un éventuel péril lié à la présence de ces constructions sur leur environnement faut-il considérer ?<p><p>La conception d'un IGH ne peut être effectuée sans une analyse des risques engendrés par la présence de tels immeubles sur leur environnement et sur le développement urbain. En effet, quand un événement indésirable y survient, un IGH peut se révéler être une menace pour ses occupants et son <p>voisinage immédiat. Les IGH sont des immeubles où plusieurs centaines de personnes sont présentes, ce qui engendre de nombreuses contraintes au niveau de la sécurité incendie notamment. En cas d'accident comme un incendie, diverses matières toxiques peuvent être libérées dans l'atmosphère, endommageant l'environnement de l'immeuble.<p><p>C'est ici que peut intervenir une méthode d'analyse des risques environnementaux permettant à un expert d'évaluer différentes situations envisagées pour l'immeuble même et son environnement. Le modèle proposé est une nouvelle méthode quantitative issue d'une approche semi-quantitative. Des matrices d'évaluation et une formulation quantitative permettent de quantifier le risque environnemental. Ce risque est déterminé pour différents secteurs autour de l'IGH car chaque environnement étudié est hétérogène et différent.<p><p>La méthode proposée reprend un ensemble de paramètres déterminés à l'aide de critères d'évaluation et de paramètres géométriques tels que la différence d'altitude entre les immeubles, la distance, etc. Nous verrons comment ces paramètres influencent le modèle et l'analyse de risques environnementaux. Un ensemble de simulations numériques seront effectuées sur un panel de cas d'études simples afin de valider le programme. Deux IGH actuellement détruits ont été étudiés avec pour objectif de comparer les résultats obtenus avec la réalité de la situation ainsi que les différentes propositions correctives. Pour chaque étude, des critiques et commentaires seront produits afin de se rattacher à la réalité des situations décrites.<p><p>The high-rise buildings (HRB) are symbolic constructions linked most often to scarce building lands, urban density challenges for big cities and the problematic of sustainable construction. However, an HRB is not limited to just these items alone: what risk impact does an HRB have on the environment? What analysis method of possible risk on the environment is to be considered for the presence of constructions?<p><p>HRB design cannot be done without any environmental risk assessment for such buildings on their environment or their impact on urban development. When an unwanted event occurs, an HRB can be a threat to its occupants and its immediate vicinity. The presence of large numbers of people in those building definitely generates a lot of problems at the level of fire safety, for example. Accidents such as a fire can release toxic materials, which will thus impact the environment of the building.<p><p>In such circumstances, a method of analysis of environmental risks come useful to experts to assess the different situations to be considered for the building itself. The proposed model is a new quantitative method which is the result of a semi-quantitative approach. Quantifying the environmental risk is made possible by evaluation matrices and quantitative formulation. This risk is determined for various sectors around HRB because every environment is heterogeneous and different.<p><p>The proposed method incorporates a set of parameters which were determined by means of evaluation criteria and geometrical parameters such as the difference in height between the buildings, distance, etc. We will see how these parameters affect the model and analysis of environmental risks. A set of simulations are performed on a range of simple models to validate the program. Two HRBs which have now been demolished were studied so as to compare the results obtained with the real-life of the situation and the corrective different proposals. For each study, criticism and comments will be produced to relate to the reality of the situations which has been described.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Made available in DSpace on 2016-04-27T16:57:26Z (GMT). No. of bitstreams: 1 Marcio Vieira de Almeida.pdf: 1460243 bytes, checksum: a4f44f26cc2c378ae48bfea70049311a (MD5) Previous issue date: 2013-06-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The focus on this research is the learning and teaching of Differential and Integral Calculus, through the reading of articles written by the researcher David Tall. It is a bibliographical theoretical research, in the modality of panorama, in which the organization is also based on elements of Content Analysis, according to Bardin. We present information about the biography of the English researcher and his relationship with the community of national research. The CAPES Thesis Database was studied, with the objective of identifying the use of theories developed by Tall in national researches. The material for analysis, used for the development of the panorama, was based on 14 articles, taken from the session Limits, Infinity & Infinitesimals of the academic website of the English researcher. The theoretical elements and the approaches in teaching formulated to the concepts real numbers, infinity, limits, continuity, derivatives, integral and differential equations are highlighted in this material. The panorama brings summaries and analysis of theoretical elements, besides highlighting important information on the learning and teaching of Differential and Integral Calculus under Tall s perspectives. With this research, we hope to have contributed to both research and teaching practice / Esta pesquisa tem por foco a aprendizagem e o ensino do Cálculo Diferencial e Integral. Trata-se da realização de um panorama de artigos de autoria de David Tall relacionados a esse tema. É um estudo teórico de caráter bibliográfico, na modalidade panorama, cuja organização se pautou também em elementos da Análise de Conteúdo, segundo Bardin. São apresentados dados sobre a biografia do pesquisador inglês e a relação dele com a comunidade de pesquisa nacional. É realizado um levantamento, no banco de dissertações e teses da CAPES, com a intenção de identificar a utilização dos elementos teóricos desenvolvidos por Tall, em pesquisas nacionais. O material de análise, utilizado para o desenvolvimento do panorama, constituiu-se de 14 artigos, retirados da seção Limits, Infinity & Infinitesimals do sítio acadêmico do pesquisador. São destacados, nesse material, os elementos teóricos e as abordagens para o ensino formuladas para os conceitos: números reais, infinito, limites, continuidade, derivada, integral e equações diferenciais. O panorama traz sínteses e análises de elementos teóricos, além de colocar em evidência dados importantes sobre a aprendizagem e o ensino do Cálculo Diferencial e Integral, na perspectiva de Tall. Com a apresentação deste trabalho espera-se ter contribuído tanto com a pesquisa quanto com a prática docente

Neste trabalho foi desenvolvido um modelo para análise tridimensional não linear geométrica de edifícios considerando a influência de todas as partes componentes do sistema estrutural, incluindo a ligação núcleo-laje e o solo de fundação. Pilares e vigas são modelados com elementos finitos de barra com seção transversal de forma qualquer, enquanto as lajes são modeladas por elementos finitos de casca. Ambos consideram o comportamento não linear geométrico e adotam como graus de liberdade posições nodais e vetores generalizados ao invés de deslocamentos e rotações, sendo também considerado para o elemento de barra o grau de liberdade de empenamento da seção. Apresenta-se uma estratégia cinemática para o acoplamento de topo entre os elementos de casca e a seção dos elementos de barra, gerando assim um elemento de núcleo com diafragma. O acoplamento se dá através de uma matriz de incidência cinemática responsável por inserir na Hessiana e no vetor de forças internas do elemento de barra que discretiza o núcleo as contribuições de elementos de casca a ele conectadas. Admite-se para os materiais do edifício a lei constitutiva elástico-linear de Saint Venant-Kirchhoff e a não linearidade geométrica é considerada através de uma formulação Lagrangiana total com cinemática exata. A flexibilidade dos apoios é considerada através de uma matriz de rigidez do sistema solo-fundação. Esta matriz é calculada em outro programa de acoplamento entre o Método dos Elementos de Contorno e o Método dos Elementos Finitos por meio de uma estratégia numérica baseada, por sua vez, no Teorema de Betti-Maxwell. A estratégia consiste na determinação de coeficientes de flexibilidade de pontos sobre uma malha discreta do sistema solo-fundação, sendo o solo modelado via Método dos Elementos de Contorno com uso da solução fundamental de Mindlin e os elementos estruturais de fundação, que podem incluir placas, sapatas, blocos e estacas, são modeladas com elementos finitos convencionais de barra e de casca. O programa permite a análise de edifícios completos, considerando a influência do empenamento dos núcleos nos pavimentos e também os efeitos da interação solo-estrutura. Exemplos numéricos são apresentados para confirmar a eficiência e demonstrar o potencial de aplicação da formulação proposta. / In this thesis a numerical model for geometric nonlinear analysis of three-dimensional structures of tall buildings was developed, considering the influence of all structural components, including the core-slab connection and the foundation system. Columns and beams are modeled by a frame finite element which can have a cross section of any shape, while the slabs are modeled by shell finite elements. Both consider the nonlinear geometric behavior and adopt nodal positions and generalized vectors as degrees of freedom instead of displacements and rotations. For the frame finite element it is also considered the cross sectional warping as a degree of freedom. A numerical strategy is presented for the coupling between the shell elements and the frame\'s cross section, thus forming a structural-core element with diaphragm. The coupling is done through a kinematic array which is responsible for inserting the contributions of shell elements, connected to the core walls, into the Hessian matrix and also into the internal force vector of the frame element used to discretize the core. The linear-elastic constitutive relation of Saint Venant-Kirchhoff is adopted for the building materials and the geometric nonlinearity is considered via a Lagrangian formulation with exact kinematics. The foundation\'s flexibility is considered through a stiffness matrix for the soil-foundation system. This matrix is computed in another program based on the numerical coupling between the Boundary Element Method and the Finite Element Method, using a numerical strategy based on the Maxwell-Betti\'s Theorem. This strategy consists in determining the flexibility coefficient of points on a discrete mesh of the soil-foundation system. The soil is modeled by the Boundary Element Method using the fundamental solution of Mindlin. The structural foundation elements, including shallow foundation, footings, blocks and piles, are modeled using conventional frame and shell finite elements. The program is applied to the analysis of complete structural systems of tall buildings, considering the influence of the core warping on the mechanical behaviour of the slabs and also the soil-structure interaction effects. Numerical examples are presented to confirm the efficiency and to demonstrate the potential application of the proposed formulation.

Indivíduos, populações e espécies tendem a usar e selecionar habitats de modo não-aleatório. Consequentemente, a perda e a degradação de habitats geram impactos distintos sobre os organismos dependendo de seus atributos. Os efeitos da perda de habitat são claros – os organismos são eliminados ou desalojados por falta de habitat ou baixo sucesso reprodutivo. As consequências da degradação de habitat são mais sutis, e resultam na incapacidade de um ecossistema sustentar determinadas espécies. Como a perda e a degradação de habitat reduzem a disponibilidade de nichos, espera-se que táxons ecologicamente especializados e com requerimentos estreitos de nicho sejam mais propensos à extinção que generalistas. Organismos que são negativamente afetados por perda e degradação de habitat em geral exibem porte muito grande ou muito pequeno, baixa mobilidade, baixa fecundidade, reduzido recrutamento e estreitos requerimentos de nicho. Campos temperados constituem ambientes particularmente afetados por perda e degradação de habitat. No sudeste da América do Sul, como em muitas outras regiões do planeta, a expansão da agricultura e silvicultura são os principais responsáveis pela perda de habitat campestre. Os remanescentes de vegetação natural são usados para criação de gado, estando sujeitos à degradação pelo sobrepastejo, pisoteio e técnicas de manejo. Avaliar como a perda e degradação de habitat afetam a diversidade de organismos campestres é vital para o desenvolvimento de estratégias de conservação e manejo. A presente tese tem por objetivo investigar como a degradação e perda de habitat induzidas pela pecuária e silvicultura afetam a diversidade e a composição das comunidades de aves. Inicialmente, exploramos as relações entre variáveis de habitat e a composição da comunidade de aves num gradiente de altura da vegetação determinado por pastejo em campos litorâneos do Rio Grande do Sul. Posteriormente, avaliamos como variações no relevo interagem com variáveis de habitat e afetam a diversidade de aves em áreas de pecuária na Campanha gaúcha. Finalmente, avaliamos de que forma a perda de habitat resultante do estabelecimento de plantações industriais de celulose em áreas de campo afeta a composição de comunidades de aves campestres. Nossos resultados demonstram que a degradação de habitat decorrente do manejo de gado em campo nativo afeta a comunidade de aves de forma diferencial. Aves adaptadas a campos ralos ou generalistas tendem a ser beneficiadas pelo pastejo, ao passo que as espécies associadas à vegetação alta e densa são desfavorecidas. As variações na topografia reduzem os impactos da degradação de habitat nos campos. Essas variações interagem com o habitat e afetam de forma diferencial os distintos componentes da diversidade. Por outro lado, a perda de habitat decorrente da silvicultura gera um impacto de maior magnitude, alterando a composição das comunidades de aves e favorecendo aves não-campestres. Nesse contexto, impedir que novas áreas de campo nativo sejam convertidas em plantações de árvores passa a ser imperativo. Embora o manejo do gado aumente a diversidade em nível de paisagem ao criar um mosaico de manchas de vegetação de alturas distintas, maior atenção deve ser dada à manutenção e recuperação de formações densas de herbáceas de grande porte. Isso somente pode ser assegurado através de mudanças no regime do pastejo ou do desenvolvimento de técnicas de manejo alternativas. / Individuals, populations and species tend to select habitats in a non-random way. Consequently, habitat loss and degradation will have different impacts on organisms according to their traits. The effects of habitat loss are straightforward – organisms are eliminated or displaced because of the inexistence of adequate habitat or of low breeding success. Effects of habitat degradation are more subtle and result in the reduction of the capacity of an ecosystem to support some subsets of species. Since habitat loss and degradation reduce niche availability, ecologically specialized taxa with narrow niche requirements are expected to be more extinction prone than habitat generalists. Temperate grasslands have been strongly impacted by habitat loss and degradation. In southeastern South America, the expansion of agriculture and industrial pulpwood plantations are the main sources of habitat loss. Remnants of natural grassland vegetation are used for livestock ranching, being subject to habitat degradation from overgrazing, trampling and inadequate management techniques. The evaluation of how habitat loss and degradation affect the diversity of grassland organisms is vital for the development of management and conservation techniques. The main goal of this thesis is to evaluate how habitat degradation and loss related to cattle ranching and pulpwood plantations affect the diversity and composition of bird communities. We began by exploring the relationship between habitat variables and the composition of the bird community along a gradient of vegetation height determined by grazing in coastal grasslands of the state of Rio Grande do Sul. We then assessed how variations in the relief interact with habitat variables e affect the diversity of birds in rangelands of the Campanha gaúcha. Finally, we evaluated how habitat loss related with grassland afforestation for pulpwood plantations affects the composition of grassland bird communities. Our results demonstrate that habitat degradation resulting from livestock ranching in natural grasslands affects bird communities in a differential way. Birds adapted to stunted grasslands or habitat generalists tend to benefit from grazing, whereas tall-grass specialists are negatively affected. Variations in topography are responsible for reducing the impacts of habitat degradation in grasslands. These variations interact with habitat and have a differential effect on distinct components of diversity. On the other hand, the magnitude of the impact of habitat loss from afforestation is larger, altering the composition of bird communities and favoring a series of non-grassland species. In this sense, protecting remaining grasslands from afforestation is imperative. Although cattle ranching increases diversity at the landscape level by creating a mosaic of vegetation patches of different height, more attention should be given in maintaining and recovering dense formations of tall grassland plants. This can only be achieved by changing grazing regimes or developing alternative management techniques.

This thesis examined vegetation change over the last 43 years in Australia's largest contiguous alpine area, the Kosciuszko alpine zone in south-eastern Australia. Using historical and current data about the state of the most common vegetation community, tall alpine herbfield, this thesis addressed the questions: (1) what were the patterns of change at the species/genera and life form levels during this time period; (2) what were the patterns of recovery, if recovery occurred, from anthropogenic disturbances such as livestock grazing or trampling by tourists; (3) what impacts did natural disturbances such as drought have on the vegetation and how does it compare to anthropogenic disturbances; and (4) What are the benefits, limitations and management considerations when using long-term data for assessing vegetation changes at the species/genera, life form and community levels? The Kosciuszko alpine zone has important economic, cultural and ecological values. It is of great scientific and biological importance, maintaining an assemblage of vegetation communities found nowhere else in the world. It is one of the few alpine regions in the world with deep loamy soils, and contains endemic flora and fauna and some of the few periglacial and glacial features in Australia. The area also forms the core of the Australian mainland's most important water catchment and is a popular tourist destination, offering a range of recreational opportunities. The vegetation of the Kosciuszko alpine zone is recovering from impacts of livestock grazing and is increasingly exposed to pressures from tourism and anthropogenic climate change. At the same time, natural disturbances such as drought and fire can influence the distribution, composition and diversity of plants. Thus, there is a need for detailed environmental data on this area in order to: (1) better understand ecological relationships; (2) understand existing and potential effects of recreational and management pressures on the region; (3) provide data against which future changes can be assessed; and (4) provide better information on many features of this area, including vegetation, for interpretation, education and management. The research in this thesis utilised three types of ecological information: (1) scientific long-term datasets; (2) photographic records; and (3) a comparison of disturbed and undisturbed vegetation. This research analysed data from one of the longest ongoing monitoring programs in the Australian Alps established by Alec Costin and Dane Wimbush in 1959. Permanent plots (6 transects and 30 photoquadrats) were established at two locations that differed in the time since grazing and have been repeatedly surveyed. Plots near Mt Kosciuszko had not been grazed for 15 years and had nearly complete vegetation cover in 1959, while plots near Mt Gungartan showed extensive impacts of grazing and associated activities which only ceased in 1958. Some transect data from 1959 to 1978 have been analysed by the original researchers. The research presented in this thesis extends this monitoring program with data from additional surveys in 1990, 1999 and 2002 and applies current methods of statistical evaluation, such as ordination techniques, to the whole data set for the first time. Results indicated that the recovery from livestock grazing and the effects of drought have been the main factors affecting vegetation. Recovery from livestock grazing at the three transects at Gungartan was slow and involved: (1) increasing genera diversity; (2) increasing vegetation cover; (3) decreasing amounts of bare ground; and (4) a directional change over time in species composition. Patterns of colonisation and species succession were also documented. In 2002, 44 years after the cessation of grazing, transects near Mt Gungartan had similar vegetation cover and genera diversity to the transects near Mt Kosciuszko, but cover by exposed rock remained higher. A drought in the 1960s resulted in a temporary increase of litter and a shift in the proportional cover of life forms, as grasses died and herb cover increased at both locations. Proportions of cover for life forms reverted to pre-drought levels within a few years. The results also highlighted the spatial variability of tall alpine herbfield. The photoquadrats were surveyed in the years 1959, 1964, 1968, 1978 and 2001 and are analysed for the first time in this thesis. After comparing a range of methods, visual assessment using a 130 point grid was found to be the most suitable technique to measure vegetation cover and genera diversity. At the 18 quadrats near Mt Gungartan, there was a pattern of increasing vegetation cover as bare areas were colonised by native cudweeds and the naturalized herb Acetosella vulgaris. Revegetation from within bare areas largely occurred by herb species, while graminoids and shrub species predominately colonised bare ground by lateral expansion from the edges, eventually replacing the colonising herbs. At the 12 quadrats near Mt Kosciuszko, vegetation cover was almost complete in all years surveyed except 1968, which was at the end of a six year drought. Similar to the results from the transect study, the drought caused an increase in litter at both locations as graminoid cover declined. Initially herb cover increased, potentially as a result of decreased competition from the graminoids and a nutrient spike from decaying litter, but as the drought became more severe, herb cover also declined. Graminoid cover rapidly recovered after the drought, reaching pre-drought levels by 1978, and was at similar levels in 2001. Herb cover continued to decline after peaking in 1964. The photoquadrat study also documented the longevity and growth rates of several species indicating that many taxa may persist for several decades. It further provided insights into replacement patterns amongst life forms. In addition to assessing vegetation change following livestock grazing and drought at the long-term plots, recovery from tourism impacts was examined by comparing vegetation and soils on a closed walking track, with that of adjacent undisturbed tall alpine herbfield at a series of 22 paired quadrats. Fifteen years after the track was closed there was limited success in restoration. Over a quarter of the closed track was still bare ground with non-native species the dominant vegetation. Plant species composition differed and vegetation height, soil nutrients and soil moisture were lower on the track which had a higher compaction level than adjacent natural vegetation. The results presented in this thesis highlight that tall alpine herbfield is characterised by nearly entire vegetation cover which is dominated by graminoids, followed by herbs and shrubs in the absence of disturbance by livestock grazing, trampling or drought. The studies also showed that under quot;average" conditions, the relative cover of herbs and graminoids remained fairly stable even though there can be considerable cycling between them. Spatial variability in terms of taxa composition was high. The only common introduced species in unrehabilitated sites was Acetosella vulgaris, which was effective at colonising bare ground but was eventually replaced by other native species. However, in areas actively rehabilitated, such as on the closed track, non-native species introduced during revegetation efforts still persist with high cover 15 years after their introduction. Monitoring of vegetation change is also important at the landscape scale. This thesis provides a review of the potential use, the limitations and the benefits of aerial photography to examine vegetation change in the Kosciuszko alpine zone. Numerous aerial photography runs have been flown over the area since the 1930s for government agencies, industry and the military. Some of these records have been used to map vegetation communities and eroding areas at a point in time. Other studies compared different types and scales of photographs, highlighting in particular the benefits and potential of large scale colour aerial photography to map alpine vegetation. However, despite their potential to assess vegetation change over time, a temporal comparison of vegetation in the Kosciuszko alpine zone from aerial photographs has not been completed to this date. Historical photographs may not be easy to locate or access and difficulties with vegetation classification may restrict the practicality of using historical aerial photographs to assess vegetation change. Despite these issues, aerial photography may provide a very useful and efficient tool to assess changes over time when applied appropriately, even in alpine environments. The development of digital classification techniques, the application of statistical measures of error to both methodology and data, and the application of geographic information systems are likely to further improve the practicality of historical aerial photographs for the detection of vegetation change and assist in overcoming some of the limitations. The results presented in this thesis highlight the need for limiting disturbance, for ongoing rehabilitation of disturbed areas and for long-term monitoring in the Kosciuszko alpine zone. The results contribute to our understanding of how vegetation may change in the future and may be affected by new land use activities and climate change. This type of information, which otherwise would require the establishment of long-term studies and years of monitoring, can assist land managers of this and other important protected areas. The study highlights how the use and expansion of already existing datasets to gather ecological information can save considerable money and time, providing valuable data for current and emerging issues.

No abstract available. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1986.

Submitted by Denize Lourenço (biblicfp@cfp.ufcg.edu.br) on 2017-12-29T12:31:10Z No. of bitstreams: 1 MARIA CELMA VIEIRA SANTOS - DISSERTAÇÃO PROFLETRAS 2016.pdf: 2172451 bytes, checksum: 447c7a89ec3fa3ef428cc0710ee93d74 (MD5) / Made available in DSpace on 2017-12-29T12:31:10Z (GMT). No. of bitstreams: 1 MARIA CELMA VIEIRA SANTOS - DISSERTAÇÃO PROFLETRAS 2016.pdf: 2172451 bytes, checksum: 447c7a89ec3fa3ef428cc0710ee93d74 (MD5) Previous issue date: 2016-11-23 / Neste trabalho, a leitura é concebida como uma prática social, construída através do diálogo, da troca de experiências e da interação. O objetivo geral desta pesquisa é aplicar a prática da leitura do Pensar Alto em Grupo (PAG), na interface com textos do eixo transversal, como contribuição para a formação do aluno como leitor crítico e reflexivo e o professor como agente de letramento. A discussão teórica abrangeu as concepções de leitura segundo Coracini (1995;2005), os estudos acerca do letramento (KLEIMAN, 1995; 2006; SOARES, 2006; STREET, 2014), a co-construção dos sentidos na interação verbal (PONTERCORVO, 2005), a concepção de sujeito sócio-historicamente constituído (BAKHTIN, 2003) e o letramento crítico (FREIRE, 1987; 1996). A metodologia utilizada foi a qualitativa de natureza interpretativista (BORTONI-RICARDO, 2009), por meio da qual foi realizada uma pesquisa-ação (THIOLLENT, 1986), focalizando a mediação como estratégia facilitadora da compreensão leitora e a orquestração das vozes dos alunos. A pesquisa foi realizada com um grupo de sete alunos do 9º ano do Ensino Fundamental, de uma escola pública estadual. Os instrumentos para coleta de dados foram o PAG (ZANOTTO, 2014) e os diários reflexivos de leitura (MACHADO, 1998). A análise dos dados evidenciou a importância do PAG como instrumento pedagógico - uma vez que por meio dessa prática foi possível garantir espaço para a voz e para a subjetividade dos alunos, além de estimular a argumentação e a construção da criticidade. A utilização das perguntas como elemento mediador estimulou a reflexão e incitou a interação entre os participantes. No final do processo, é possível afirmar que houve uma reconfiguração na minha atuação, pois assumi o papel de mediadora e de agente de letramento. Palavras / This study conceives reading as a social practice built through dialogue, through the exchanging of experiences and through interaction. The main goal is to apply the Think-Aloud (TA) reading technique with texts from the transverse axis, both as a contribution for the students’ development as critical and reflective readers and for the teacher as a literacy facilitator. The theoretical framework comprises Coracini’s (1995;2005) concepts of reading, the literacy studies (KLEIMAN 1995; 2006; SOARES 2006, STREET, 2014), the co-construction of the senses in verbal interaction (PONTECORVO, 2005), (BAKHTIN, 2003) notion of the subject constructed socially and historically, and (FREIRE, 1987;1996) critical literacy. The methodology used was qualitative of interpretative nature, (BORTONI-RICARDO, 2009), through which an Action Research (THIOLLENT,1986) was conducted so as to focus on my practice as a mediator and caster of the students’ voices. The study was done with a group of seven students from a public school in the 9th year of Brazilian “Ensino Fundamental”. The tools for collecting data were PAG (ZANOTTO, 2014) and the reflective reading journals (MACHADO, 1998). Data analysis showed the importance of PAG as a pedagogical tool – once it allows students to have a voice and to exercise their subjectivity while stimulating argumentation and the building of criticism. The use of questions as a mediation tool motivated reflection and incited interaction among the participants. At the end of the process, it is possible to state that there was a reconfiguration of my practice, for I took on the role of mediator and literacy facilitator.