Made available in DSpace on 2014-07-29T15:10:32Z (GMT). No. of bitstreams: 1 Tese Tatiana S Fiuza.pdf: 214501 bytes, checksum: abb8f10f906147d3c8811901c4bb08ab (MD5) Previous issue date: 2009-01-22 / The purpose of this work is to perform the pharmacognostic studies of the species Hyptidendron canum (Pohl ex Benth.) Harley (Lamiaceae) and Eugenia uniflora L. (Myrtaceae), investigate the population variability of the constituents of the essential oil from H. canum leaves and inflorescences, and assess the bioactivity of the crude ethanol extracts and fractions from leaves of this plants against microorganisms (bacteria and the fungus Candida albicans) and on Oreochromis niloticus Linnaeus. For the variability study of the H. canum essential oil, samples obtained from leaves and inflorescences from Hidrolândia, Silvânia, Bela Vista and Goiânia cities were analyzed by gas chromatography and gas chromatography with mass spectrometry. The anatomic analysis and the phytochemical screening of the leaves from the two species were performed using conventional techniques. The antimicrobial activity was assessed with Gram-positive and Gram-negative bacteria and with the Candida albicans fungus using the well diffusion test and the agar dilution method to determine the minimal inhibitory concentration (MIC). The biological activities of the crude ethanol extract and ethyl acetate, hexanic and chloroformic fractions of the leaves from the two species were tested in O. niloticus fish hepatopancreas and gill. The H. canum essential oils analysis indicated high chemovariability in the oils from different locations. The phytochemical screening and the thin layer chromatography (TLC) analysis of the H. canum leaves evidenced the presence of flavonoids, saponins, terpenes and lignans, while the E. uniflora leaves evidenced the presence of tannins, steroids, triterpenes, anthraquinonic heterosides, saponinic and flavonoids. As for the antimicrobial activity testing, the crude ethanol extracts from both species presented antimicrobial activity against all the microorganisms tested and the E. uniflora ethyl acetate fraction presented satisfactory activity against resistant Pseudomonas aeruginosa. The H. canum crude extract and fractions presented vasoactive activity in the hepatopancreas and gill of the tilapias, causing varying degrees of vasodilation and vascular congestion. An apparent proliferation of blood capillaries was detected in the hepatopancreas of the fish that ingested the hexanic fraction. The E. uniflora crude extract and the ethyl acetate, chloroform and hexanic fractions caused vasodilation, vascular congestion and tissue alterations in the O. niloticus hepatopancreas and gills / O presente trabalho teve por objetivo realizae o estudo farmacognóstico das espécies Hyptidendron canum (Pohl ex Benth.) Harley (Lamiaceae) e Eugenia uniflora L. (Myrtaceae), investigar a variabilidade populacional dos constituintes do óleo essencial das folhas e inflorescências da H. canum e avaliar a bioatividade dos extratos etanólicos brutos e das frações das folhas das referidas plantas contra icrorganismos (bactérias e fungo) e em Oreochromis niloticus Linnaeus. Para o estudo da variabilidade do óleo essencial da H. canum, as folhas e inflorescências foram coletadas nos municípos de Hidrolândia, de Silvânia, de Bela Vista e de Goiânia e seus óleos essenciais foram analisados por cromatografia gasosa e cromatografia gasosa acoplada a espectrometria de massa. A análise anatômica e a prospecção fitoquímica das folhas das duas espécies foram realizadas utilizando as técnicas convencionais. A atividade antimicrobiana foi avaliada com bactérias Gram-positivas e Gramnegativas e com o fungo Candida albicans, usando o teste de difusão em poço e o método de diluição em ágar, para determinar a concentração inibitória mínima (CIM). As atividades biológicas do extrato etanólico bruto e das frações acetato de etila, hexânica e clorofórmica das folhas das duas espécies foram avaliadas no hepatopâncreas e brânquias do peixe O. niloticus L. A análise dos óleos essenciais da H. canum indicou elevada quimiovariabilidade nos óleos dos diferentes locais. A triagem fitoquímica e a cromatografia em camada delgada (CCD) das folhas da H. canum evidenciaram a presença de flavonóides, saponinas, terpenos e lignanas e das folhas da E. uniflora, a presença de taninos, esteróides, triterpenos, heterosídeos antraquinônicos, saponínicos e flavonóides. Na avaliação da atividade antimicrobiana, observou-se que os extratos etanólicos brutos das duas espécies demonstraram atividade antimicrobiana contra todos os microrganismos testados, e a fração acetato de etila da E. uniflora apresentou boa atividade contra Pseudomonas aeruginosa resistentes aos antibióticos convencionais. O extrato bruto e as frações da H. canum apresentaram atividade vasoativa no hepatopâncreas e brânquias das tilápias, promovendo, em maior ou menor grau, vasodilatação e congestão vascular. Detectou-se ainda aparente proliferação dos capilares sanguíneos no hepatopâncreas dos peixes tratados com a fração hexânica. Verificou-se que tanto o extrato bruto, quanto as frações acetato de etila, clorofórmica e hexânica da E. uniflora promoveram, no hepatopâncreas e nas brânquias de O. niloticus, vasodilatação, congestão vascular e alterações teciduais

Made available in DSpace on 2014-07-29T15:30:33Z (GMT). No. of bitstreams: 1 CIRLANE SILVA FERREIRA.pdf: 793070 bytes, checksum: b29f3e5051b2e84947431f66651a7662 (MD5) Previous issue date: 2006-03-31 / The state of Goiás represents a high risk to schistosomiasis stablishment area The presence of the intermediate host Biomphalaria sp added to high migration levels of people from endemic regions of the country are evidences that favour the installation of this disease life cycle In this state of Goiás there are reports of high parasitary intensity and even cases of paraplegia associated with schistosomiasis. The Stryphnodendron polyphyllum (Martius 1837) known locally as Barbatimão de folha pequena is reported as a molluscicide plant This paper assesses the activity of gross bark extracts from S polyphyllum on the metabolism and on the acid-alkaline balance of B glabrata The mollusks were exposed to the extract at 25 and 50 mg/L concentrations for 24 hours and compared to a control group The concentrations of glucose calcium urea proteins and the activity of the following enzymes dehydrogenases lactate and aminotransferases were estimated using the spectrophotometry method The organic acids citrate propionate α- cetoglutarate succinate acetate malate fumarate pyruvate and lactate were detected and quantified using the liquid chromatography method Of all the organic acids found in the hemolymph, only citrate and propionate presented a significant alteration The acid-alkaline balance was verified by measuring the concentrations found in the pH oxygen carbonic gas carbonate ions and oxygen saturation using Radiomiter equipment The S polyphyllum extract tested proved effective due to celular toxicity on B glabrata(Say 1818) Alterations verified in the biochemical dosages reflect the metabolic disturbances in the hemolymph of the mollusk The Cirlane Silva Ferreira x extract interference caused an increase in the levels of glucose urea calcium aspartate alanine aminotransferases and carbonic gas pressure simultaneously causing a decrease in the levels of lactate dehydrogenase pH oxygen pressure carbonate ions and oxygen saturation This study confirms the bioactivity of the S polyphyllum aqueous extract on B glabrata One of the main contributions of the methodology used is that it enabled observation after direct contact with the extract that proved bioactivity on the metabolism of the mollusk The analysis of the aqueous extract taken from the bark of the barbatimão may be the basis for new and less toxic as well as less costly alternative for the control of schistosomiasis in Brazil, where the savannah is vast and financial resources are often scarce in the health sector / O Estado de Goiás representa uma área de alto risco ao estabelecimento da esquistossomose A presença do hospedeiro intermediário Biomphalaria sp somada à elevada migração de pessoas oriundas de regiões endêmicas do país são fatores que favorecem a instalação do ciclo desta doença Há no Estado de Goiás relatos de casos com alta intensidade parasitária e até mesmo um caso com paraplegia associada a esquistossomose O Stryphnodendron polyphyllum (Martius 1837) conhecido como Barbatimão de Folha Pequena é relatado como planta moluscicida Neste trabalho avaliou-se a atividade de extratos brutos da casca do caule de S polyphyllum sobre o metabolismo e o equilíbrio ácido-base do B glabrata Os moluscos foram expostos ao extrato por 24 horas nas concentrações de 25 e 50 mg/L e comparados com um grupo controle Foram avaliadas as concentrações de glicose cálcio uréia proteínas e atividade das enzimas lactato desidrogenase e aminotransferases pelo método de espectrofotometria Os ácidos orgânicos citrato propionato α-cetoglutarato succinato acetato malato fumarato piruvato e lactato foram dosados pelo método da cromatografia líquida Dos ácidos orgânicos encontrados na hemolinfa apenas o citrato e o propionato tiveram uma alteração significativa O equilíbrio ácido-base foi verificado pela medida das concentrações de pH oxigênio gás carbônico íons carbonatos e saturação de oxigênio através de equipamento Radiomiter O extrato de S polyphyllum testado demonstrou ação efetiva observada pelo estabelecimento de toxicidade celular sobre B glabrata (Say, 1818) As alterações apresentadas nas dosagens bioquímicas refletem os distúrbios metabólicos ocorridos na hemolinfa deste molusco A interferência deste extrato fez com que os níveis de glicose uréia cálcio aspartato alanina aminotransferases e pressão de gás carbônico se elevassem enquanto que os níveis de lactato desidrogenase pH pressão de oxigênio íons carbonato e saturação de oxigênio diminuíram Este trabalho confirma a bioatividade do extrato aquoso de S polyphyllum sobre o B glabrata Uma das principais contribuições desse estudo desenvolvido é a observação pós-contato direto com o extrato que demonstrou uma bioatividade sobre o metabolismo do molusco A análise de extrato aquoso obtido do caule do barbatimão pode subsidiar nova alternativa de menor toxicidade e menor custo financeiro no controle da esquistossomose no Brasil onde o Cerrado é vasto e a carência de recursos é freqüente no setor da saúde

Les réseaux neuronaux profonds sont des outils prometteurs pour l'évaluation de la biodiversité aviaire, en particulier pour la détection des chants et la classification acoustique des espèces. Toutefois, on connaît mal l’étendue de leur capacité de généralisation face à la variation intraspécifique présente dans les chants d’oiseaux, ce qui pourrait mener à des biais. Notre étude porte sur l'évaluation des performances de BirdNET, un réseau neuronal profond, pour le traitement d’un corpus d'enregistrements audio caractérisés par une variation intraspécifique significative, en utilisant l’exemple du chant du bruant des prés (Passerculus sandwichensis). Dans la population de l'île de Kent, au Nouveau-Brunswick, les individus sont suivis et enregistrés grâce à leurs bagues de couleur et la présence de microdialectes est solidement documentée. Nous avons recueilli et annoté 69 606 chants provenant de 52 individus et analysé ces données à l'aide d’une version récente de BirdNET. Nos résultats révèlent que BirdNET démontre une précision globale suffisante, prédisant correctement 81,9 % des chants, ce qui dépasse les résultats rapportés par ses développeurs. Toutefois, nous avons observé une variation considérable dans les scores de confiance et les taux de prédiction exactes entre les individus, ce qui suggère des biais potentiels. Cependant, nos recherches n'ont pas mis en évidence de variation entre les résultats des différents microdialectes, ce qui souligne la relative robustesse de l'algorithme. Nous avançons que la variation observée entre les individus est due au fait que certains d’entre eux chantent systématiquement plus près des microphones, résultant en des chants plus clairs donc plus faciles à identifier. Pour mieux comprendre le processus de prise de décision de BirdNET, nous avons tenté de produire des cartes d'activation de classe, qui constituent un outil précieux pour identifier les éléments d’un chant qui déterminent une prédiction. Cependant, il ne nous a pas été possible d’obtenir des cartes d’activation de classe d’après la version actuellement disponible du code de BirdNET sans avoir recours à des connaissances avancées en informatique. L'accès à des outils explicatifs adaptés aux innovations récentes dans les architectures de réseaux neuronaux 4 profonds serait crucial pour mieux interpréter les résultats et renforcer la confiance des utilisateurs. Nos résultats soulignent la nécessité de poursuivre les recherches sur la capacité de généralisation des réseaux neuronaux profonds pour la bioacoustique en utilisant des ensembles de données monospécifiques portant sur de plus longues périodes ou des aires de répartition géographique plus vastes. En outre, l'extension de cette étude à des espèces ayant des répertoires plus importants ou des différences plus subtiles entre le chant des individus pourrait nous informer davantage sur les limites et le potentiel des algorithmes d'apprentissage profond pour la détection et la classification acoustiques des espèces. En conclusion, notre étude démontre les performances prometteuses de BirdNET pour le traitement d'un large corpus de chants de bruants des prés, et confirme son potentiel en tant qu'outil précieux pour l'évaluation de la biodiversité aviaire. Les biais dus aux techniques d’enregistrement et la variation dans les taux de succès observés entre les individus méritent d'être étudiés plus en détail. / Machine learning, particularly deep neural networks, has gained prominence as a valuable tool in ecological studies and wildlife conservation planning. In the field of avian biodiversity assessment, deep neural networks have shown remarkable promise, particularly in acoustic species detection and classification. Despite their success, a critical knowledge gap exists concerning the generalization ability of these algorithms across intraspecific variation in bird song. This raises concerns about potential biases and misinterpretation of results. This study focuses on evaluating the performance of BirdNET, a deep neural network, in processing audio recordings characterized by significant intraspecific variation in the Savannah Sparrow (Passerculus sandwichensis) song. Savannah Sparrows are an ideal candidate for this investigation, given their well-studied population on Kent Island, New Brunswick, Canada. Each male sings a unique, unchanging song throughout its life, and the population exhibits well-documented geographical microdialects. We collected a large corpus of Savannah Sparrow songs using autonomous and focal recorders on Kent Island, yielding a total of 69,606 manually annotated songs from 52 different sparrows. We analyzed the audio data using BirdNET-Analyzer. The resulting confidence scores were used to assess the algorithm's performance across microdialects and individual birds. Our results revealed that BirdNET exhibited considerable overall accuracy, correctly predicting 81.9% of the songs, which surpassed the results reported by the developers of BirdNET. We observed variations in BirdNET's confidence scores among individual birds, suggesting potential biases in its classifications. However, our investigation indicated no evidence of distinct biases towards specific microdialects, highlighting the algorithm's relative robustness across these groups. We suspect that the variation observed amongst individuals is caused by the fact that some were singing consistently closer to microphones, yielding clearer songs. To gain insights into BirdNET's decision-making process, we sought to employ class activation maps, a valuable tool for identifying essential song elements contributing to species predictions. However, we were unable to produce class activation maps from the current version of BirdNET 6 without advanced computer science skills. Access to informative tools adapted to recent innovations in deep neural network architectures for bioacoustic applications is crucial for understanding and interpreting results better. Such tools would enhance user confidence and favour accountability for conservation decisions based on these predictions. Our findings underscore the need for further research investigating the generalization capacity of deep neural networks in bioacoustics on single-species datasets with more extensive intraspecific variation and broader geographical ranges. Additionally, expanding this investigation to species with larger song repertoires or more subtle inter-individual song differences could provide valuable insights into the limits and potential of deep learning algorithms for acoustic species detection and classification. In conclusion, our study demonstrates BirdNET's promising performance in processing a large corpus of Savannah Sparrow songs, highlighting its potential as a valuable tool for avian biodiversity assessment. Biases and variations in confidence scores observed across individual birds warrant further investigation.

No description available.

South Africa’s growing elephant populations are concentrated in relatively small enclosed protected areas resulting in the over utilisation of the available food sources. Elephants and other herbivores as well as other natural disturbances such as fires and droughts play an important role in maintaining savannah environments. When these disturbances become too concentrated in a particular area the vegetation composition may be negatively affected. Excessive damage to the vegetation would result from exceeding the capacity of a protected area to provide food resources. The effect of the 120 elephants on the vegetation of Welgevonden Private Game Reserve, is not known. The rugged terrain of this reserve makes it a difficult, time consuming and labour intensive exercise to conduct ground studies. Satellite images can be used as a monitoring tool for vegetation change and improve the quantity and quality of environmental data to be collected significantly, allowing more informed management decision-making. This study evaluated the use of satellite imagery for monitoring elephant induced vegetation change on Welgevonden Private Game Reserve. The LANDSAT Thematic Mapper multispectral images, acquired at two yearly intervals from 1993 until 2007 were used. However, no suitable images were available for the years 1997, 2001 and 2003. A series of vegetation change maps was produced and the distribution of water sources and fire occurrences mapped. The areas of change were then correlated with the spatial distribution of water points and fire occurances, with uncorrelated areas of change. This was analysed using large animal population trends, weather data and management practices. On the visual comparison of the vegetation maps, it was seen that over this time period there was some decrease and thinning of woodland, but the most notable change was the increase of open woodland and decrease in grasslands. Using only the digital change detection for the period 1993 to 2007, a general increase in vegetation cover is seen. But this generalisation is misleading, since comparing the digital change detection to the vegetation maps indicates that while vegetation cover may have increased, significant changes occurred in the vegetation types. Most of the areas of significant change that were identified showed a strong positive correlation with burnt areas. The distribution of the water sources could not be directly linked to the vegetation change although rainfall fluctuations seemed to have accelerated vegetation changes. Years with high game counts, such as 1999, also coincide with very low rainfall making it difficult to differentiate between the effects of heavy utilisation of vegetation and low rainfall. Furthermore, many of the initial vegetation changes could be the result of land use changes due to the introduction of browsers, selective grazers and elephants that allow for more natural utilisation of the vegetation. Remote sensing makes it possible to successfully track changes in vegetation and identify areas of potential elephant induced vegetation change. Vegetation changes caused by disturbances, such as fire and anthropogenic activities, can be accounted for but it is not possible to conclude with a high level of certainty that the further changes seen are solely a result of elephant damage. Further work is required to reliably isolate elephant induced vegetation changes, as well as to establish the effects these changes have on the ecosystem as a whole. / Environmental Sciences / (M. Sc. (Environmetal Sciences))

Made available in DSpace on 2014-07-29T16:26:02Z (GMT). No. of bitstreams: 1 Tese Vonedirce 2011.pdf: 4881714 bytes, checksum: d1c8bbd4c344b9b79c27aa78e3b2d930 (MD5) Previous issue date: 2011-12-16 / The alcohol sector has shown a remarkable process of expansion since 2000, towards the central Cerrado, admittedly favored by situation anchored in renewable energy and defense of national sovereignty. The state of Goias is one of the prime targets of this expansion, since 2004, primarily from 2006 to 2007, and has been concentrating a strong sugar industry in southern Goiás / Southwest Microregion of Quirinópolis (MRQ), where he spent about 4 000 ha more than 150 000 ha planted in the period, with great impact on the local socio-economy, according to previous studies, and subsidiaries of this thesis. This micro-region has favorable soil and climatic characteristics and economic importance of high logistics intra-and inter-regional exports, but the changes in land use and environmental impacts related to this process are still poorly studied. This thesis aims to understand the spatial pattern of expansion of sugarcane and the MRQ, with emphasis on soil and its use changes, considered by many authors as the agricultural frontier expansion of the 1970s, but more organized and capitalized technified, aiming prove the hypothesis that there has been setting a new centrality of the sugarcane industry in the Cerrado, focusing on production of ethanol and bio-energy, multi-scale consequences of which affect, among other things, the other pre-existing supply chains, especially food production. We analyzed in more detail the succession of land uses in the period since 2004, before the arrival of the cane in order to identify the substitution patterns of crops and pastures by the new culture and the potential for direct environmental impacts of sugarcane due observation of pressure on water resources for irrigation purposes and on soils associated with the management system of high technological standards, involving inputs and pesticides, and heavy machinery, among others. The research was based mainly on compiling data and maps, and thematic development of multi-scale cartographic documents, including use of satellite imagery and GIS analysis of census data and detailed study of various impacts on soil and water resources, with sampling Field and laboratory analysis. It is concluded that sugarcane has focused initially on the best land of the MRQ, where it has the best infrastructure in regional / state, where it stood, triumphant, with other uses, in particular, grains (soybeans), and secondarily pastures, in which continues with the current expansion. The process as in the past is supported by federal policy, now the PNE - 2030, and receives federal and state subsidies. It's still fast and plays the same model of previous agricultural expansion, occupation of Savannah in the 1970s, differing, however the fastest and well-planned action of large financial groups and the rapid formation of joint ventures and sugar and alcohol agribusiness complexes horizontal extension of those South-East and even multinationals. These groups previously selected areas where expansion triggered the installation of plants inducing a re-zoning, but retained the strategy of producing agricultural commodities. Finally, it was found that the main direct environmental impacts cultivated areas are the loss of soil biodiversity and water resources soil compaction and increase their resistance to penetration, indicating compression, and it is assumed that there is potential for erosion and also the subsequent contamination of their time, because crop management. It was concluded that MRQ experience, paradoxically, both positive and negative social and environmental impacts arising from a rapidly expanding sugarcane which materialized a new centrality of the space sector in the Central Cerrado, similar to that which occurred in the past the state of São Paulo, but this time relying on an industry already established in the south-southeast and which together make up what is called the polygon of the cane and a new center, as part of this arc expansion of sugar cane, as undeniable and great expression of state and national levels, and gradually reference also becoming international. / O setor sucroalcooleiro vem apresentando um processo notável de expansão desde 2000, rumo ao Cerrado central, reconhecidamente favorecido por conjuntura ancorada na defesa da energia renovável e soberania nacional. O estado de Goiás é um dos alvos preferenciais dessa expansão, desde 2004, principalmente 2006-2007, e vem concentrando uma forte agroindústria canavieira na região Sul Goiano/Sudoeste, Microrregião de Quirinópolis (MRQ), onde passou de cerca de 4 mil ha a mais de 150 mil ha plantados no período, com grande impacto na socioeconomia local, segundo estudos anteriores e subsidiários desta tese. Essa microrregião conta com características edafoclimáticas favoráveis e logísticas de grande relevância econômica intra e inter-regional para exportação, porém as mudanças de uso do solo e impactos ambientais relacionados a esse processo ainda são pouco estudados. A presente tese objetiva compreender o padrão espacial de expansão da cana para e na MRQ, com ênfase em solos e suas mudanças de uso, entendidas por vários autores como expansão da Fronteira Agrícola da década de 1970, porém mais organizada, tecnificada e capitalizada, visando comprovar a hipótese de que aí vem se configurando uma nova centralidade do setor sucroenergético no Cerrado, voltado à produção de etanol e bioenergia, cujas consequências multiescalares afetam, dentre outros aspectos, as demais cadeias produtivas pré-existentes, especialmente de produção de alimentos. Analisou-se com mais detalhe a sucessão de usos do solo no período desde 2004, anterior à chegada da cana, de modo a identificar os padrões de substituição de culturas e pastagens pela nova cultura e o potencial de impactos ambientais diretos da cana devida constatação de pressão sobre os recursos hídricos para fins de irrigação e sobre os solos associados ao sistema de manejo de elevado padrão tecnológico, envolvendo insumos e defensivos, além de maquinaria pesada, dentre outros. A pesquisa baseou-se principalmente na compilação de dados e mapas, e elaboração de documentos cartográficos temáticos multiescalares, incluindo uso de imagens de satélite e SIG, análise de dados censitários diversos e estudo detalhado de impactos através de entrevistas dos principais atores, de descrição e coleta de amostras de solos e recursos hídricos e análise laboratorial. Conclui-se que a cana se concentrou inicialmente nas melhores terras da MRQ, onde conta com a melhor infra-estrutura regional/estadual, e vem concorrendo, vitoriosa, com outros usos, em particular, grãos (soja), e secundariamente pastagens, nas quais prossegue com a expansão atual. O processo, como no passado está amparado em política federal, ora o PNE - 2030, e recebe subsídios federais e estaduais. Ainda está acelerado e reproduz o mesmo modelo de expansão da Fronteira Agrícola anterior, de ocupação do Cerrado dos anos de 1970, diferenciando-se, entretanto pela rápida e mais bem planejada atuação de grandes grupos financeiros e formação rápida de joint ventures e complexos agroindustriais sucroalcooleiros horizontais em extensão daqueles do Sul-Sudeste e mesmo multinacionais. Esses grupos selecionaram previamente as áreas de expansão onde desencadearam a instalação das usinas induzindo um novo zoneamento, mas mantiveram a estratégia de produção de commodities agrícolas. Por fim, constatou-se que os principais impactos ambientais diretos nas áreas cultivadas são a perda de biodiversidade dos solos e dos recursos hídricos a compactação dos solos e a aumento de sua resistência à penetração, indicando compactação, e supõe-se que há potencial de erosão subsequente e também de sua contaminação com o tempo, devido manejo da cultura. Conclui-se também que a MRQ vivencia, paradoxalmente, os impactos socioambientais positivos e negativos decorrentes de uma expansão sucroalcooleira que materializou rapidamente uma nova centralidade espacial do setor no Cerrado Central, similar àquela ocorrida no passado no estado de São Paulo, porém desta feita contando com um setor já consolidado no Sul-Sudeste e que juntos se configuram no que se está chamando de polígono da cana e numa nova centralidade, esta como parte do arco de expansão da cana, já de inegável e grande expressão estadual e nacional, e aos poucos se tornando referência também internacional.

South Africa’s growing elephant populations are concentrated in relatively small enclosed protected areas resulting in the over utilisation of the available food sources. Elephants and other herbivores as well as other natural disturbances such as fires and droughts play an important role in maintaining savannah environments. When these disturbances become too concentrated in a particular area the vegetation composition may be negatively affected. Excessive damage to the vegetation would result from exceeding the capacity of a protected area to provide food resources. The effect of the 120 elephants on the vegetation of Welgevonden Private Game Reserve, is not known. The rugged terrain of this reserve makes it a difficult, time consuming and labour intensive exercise to conduct ground studies. Satellite images can be used as a monitoring tool for vegetation change and improve the quantity and quality of environmental data to be collected significantly, allowing more informed management decision-making. This study evaluated the use of satellite imagery for monitoring elephant induced vegetation change on Welgevonden Private Game Reserve. The LANDSAT Thematic Mapper multispectral images, acquired at two yearly intervals from 1993 until 2007 were used. However, no suitable images were available for the years 1997, 2001 and 2003. A series of vegetation change maps was produced and the distribution of water sources and fire occurrences mapped. The areas of change were then correlated with the spatial distribution of water points and fire occurances, with uncorrelated areas of change. This was analysed using large animal population trends, weather data and management practices. On the visual comparison of the vegetation maps, it was seen that over this time period there was some decrease and thinning of woodland, but the most notable change was the increase of open woodland and decrease in grasslands. Using only the digital change detection for the period 1993 to 2007, a general increase in vegetation cover is seen. But this generalisation is misleading, since comparing the digital change detection to the vegetation maps indicates that while vegetation cover may have increased, significant changes occurred in the vegetation types. Most of the areas of significant change that were identified showed a strong positive correlation with burnt areas. The distribution of the water sources could not be directly linked to the vegetation change although rainfall fluctuations seemed to have accelerated vegetation changes. Years with high game counts, such as 1999, also coincide with very low rainfall making it difficult to differentiate between the effects of heavy utilisation of vegetation and low rainfall. Furthermore, many of the initial vegetation changes could be the result of land use changes due to the introduction of browsers, selective grazers and elephants that allow for more natural utilisation of the vegetation. Remote sensing makes it possible to successfully track changes in vegetation and identify areas of potential elephant induced vegetation change. Vegetation changes caused by disturbances, such as fire and anthropogenic activities, can be accounted for but it is not possible to conclude with a high level of certainty that the further changes seen are solely a result of elephant damage. Further work is required to reliably isolate elephant induced vegetation changes, as well as to establish the effects these changes have on the ecosystem as a whole. / Environmental Sciences / (M. Sc. (Environmetal Sciences))