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In recent years it has become widely accepted that the natural systems on which we depend for survival are being degraded by human activity. It is no longer a question of if we need to reduce our impact upon the planet, but of the extent to which we need to change our behaviour, and how soon we need to act. Such change will depend upon the support of voters, governments, and the international community and will require wide spread changes in attitudes and behaviour. Using the social identity approach as a framework, the current programme of research focuses on rural land users in Australia and the effectiveness of sustainable land use campaigns directed at them from both urban and rural sources. The studies provide a novel contribution to the area by demonstrating the effects of intergroup threat on group-based communication, in particular, the perception of threat to rural identity and the effect on urban and rural messages aimed at changing land use behaviour. Conclusions about broader social influence processes were also made by assessing rural participants’ perceptions of the degree to which others are influenced. Although the studies are based in the context of rural Australian land users, the results and theoretical implications can be applied to any situation wherein one group is attempting to change the attitudes and behaviours of another group. This could range from local interest groups trying to convince each other of the merits of their ideas through to political parties and nations calling for united and decisive action on global issues. Such groups ignore issues of power and status at the risk of ineffective communications or even a backlash in opinion and behaviour. Six studies were conducted, including five survey studies with rural landholders and one experiment with students at a rural campus. Study 1 (N = 251) was an evaluation of sustainable land use campaigns in general, comparing those from urban sources to those from rural sources. Study 2 (N = 585) extended this by assessing the moderating role of intergroup threat perceptions. This study also measured the perceptions of influence of urban and rural messages on urban people and other rural people. Study 3 (N = 98) assessed the influence of an actual land use campaign delivered by an ingroup source on individuals’ attitudes and behaviours and the perceived influence on others. Study 4 (N = 249) built upon Study 2 but included additional measures to address some of the inconsistencies between Studies 1 and 2. To address the psychological underpinnings of group-based influence, Study 5 (N = 124) included measures of trust in urban and rural sources as well as reports of influence, agreement, and past behaviour. To conclude, Study 6 (N = 64) provided an experimental test of persuasion by manipulating the source of the message. Self-reported identification and intergroup threat were examined as moderators of group-based persuasion. Furthermore, attributions of constructiveness were explored as a possible reason for the superior influence of ingroups. Across the six studies it was found that ingroup messages were consistently more influential than outgroup messages. Attributions of trust and constructiveness helped to explain the superior influence of ingroups. In terms of perceptions of influence on others, there was a third-person effect for urban messages but rural people did not differentiate between themselves and other rural people in response to rural messages. Furthermore, rural identification was associated with greater reported influence from the ingroup source and perceived threat was associated with increased influence of rural messages compared to urban messages. These findings have clear implications for attempts at changing attitudes between groups, particularly where there is a salient and competitive intergroup context. Outgroups operate at a distinct disadvantage in delivering persuasive communications, especially if ingroup identification is high or there is a perception of threat stemming from the communicating group. Evidence of the persuasiveness of ingroups compared to outgroups is further strengthened by the perceptions of similarity in influence of rural sources for self and other ingroup members. The findings on trust and constructiveness hint at the possibility of overcoming barriers to outgroup persuasion if positive motives for the messages can be established. Of course, this depends on the severity of the intergroup context and the nature of communication. Recommendations are made for a collaborative approach to achieving change.

Dryland-salinity management options aim to positively influence the adverse human-induced processes which lead to salinisation of top-soil. Specifically, the processes causing dryland-salinity are rising saline groundwater table and soil erosion. In the Avon region of Western Australia, the management options are evaluated solely on the basis of their efficiency in lowering groundwater tables. However, recently the need to take into account also their wider impact on the ecosystems' resilience has been recognised as well. Nevertheless, the tool to assess these impacts is missing. The aim of this thesis is to synthesise the missing tool from existing ecosystem services-based land-use evaluation frameworks, which would fit the environmental issue, regional socio-economic demands and the existing dryland salinity management options' efficiency evaluation framework. The thesis builds on secondary data and describes (i) the environmental issue of dryland salinity in Australia, (ii) the dryland salinity-environmental, economic, social and political environments of the Avon region, and (iii) five chosen evaluation frameworks which assess the impact of land-use on ecosystem resilience. The proposed optimal framework for the Avon region is then a combination of two existent frameworks: (i) ecosystem resilience evaluation framework & (ii) the ecosystem services economic valuation framework. Where the inputs of the proposed optimal framework are: (i) soil properties, (ii) external natural and anthropogenic drivers and (iii) beneficiaries; the transfer phase is represented by the soil processes; and the output of the framework are (i) ecosystem services and (ii) their economically valued benefits.

In recent years it has become widely accepted that the natural systems on which we depend for survival are being degraded by human activity. It is no longer a question of if we need to reduce our impact upon the planet, but of the extent to which we need to change our behaviour, and how soon we need to act. Such change will depend upon the support of voters, governments, and the international community and will require wide spread changes in attitudes and behaviour. Using the social identity approach as a framework, the current programme of research focuses on rural land users in Australia and the effectiveness of sustainable land use campaigns directed at them from both urban and rural sources. The studies provide a novel contribution to the area by demonstrating the effects of intergroup threat on group-based communication, in particular, the perception of threat to rural identity and the effect on urban and rural messages aimed at changing land use behaviour. Conclusions about broader social influence processes were also made by assessing rural participants’ perceptions of the degree to which others are influenced. Although the studies are based in the context of rural Australian land users, the results and theoretical implications can be applied to any situation wherein one group is attempting to change the attitudes and behaviours of another group. This could range from local interest groups trying to convince each other of the merits of their ideas through to political parties and nations calling for united and decisive action on global issues. Such groups ignore issues of power and status at the risk of ineffective communications or even a backlash in opinion and behaviour. Six studies were conducted, including five survey studies with rural landholders and one experiment with students at a rural campus. Study 1 (N = 251) was an evaluation of sustainable land use campaigns in general, comparing those from urban sources to those from rural sources. Study 2 (N = 585) extended this by assessing the moderating role of intergroup threat perceptions. This study also measured the perceptions of influence of urban and rural messages on urban people and other rural people. Study 3 (N = 98) assessed the influence of an actual land use campaign delivered by an ingroup source on individuals’ attitudes and behaviours and the perceived influence on others. Study 4 (N = 249) built upon Study 2 but included additional measures to address some of the inconsistencies between Studies 1 and 2. To address the psychological underpinnings of group-based influence, Study 5 (N = 124) included measures of trust in urban and rural sources as well as reports of influence, agreement, and past behaviour. To conclude, Study 6 (N = 64) provided an experimental test of persuasion by manipulating the source of the message. Self-reported identification and intergroup threat were examined as moderators of group-based persuasion. Furthermore, attributions of constructiveness were explored as a possible reason for the superior influence of ingroups. Across the six studies it was found that ingroup messages were consistently more influential than outgroup messages. Attributions of trust and constructiveness helped to explain the superior influence of ingroups. In terms of perceptions of influence on others, there was a third-person effect for urban messages but rural people did not differentiate between themselves and other rural people in response to rural messages. Furthermore, rural identification was associated with greater reported influence from the ingroup source and perceived threat was associated with increased influence of rural messages compared to urban messages. These findings have clear implications for attempts at changing attitudes between groups, particularly where there is a salient and competitive intergroup context. Outgroups operate at a distinct disadvantage in delivering persuasive communications, especially if ingroup identification is high or there is a perception of threat stemming from the communicating group. Evidence of the persuasiveness of ingroups compared to outgroups is further strengthened by the perceptions of similarity in influence of rural sources for self and other ingroup members. The findings on trust and constructiveness hint at the possibility of overcoming barriers to outgroup persuasion if positive motives for the messages can be established. Of course, this depends on the severity of the intergroup context and the nature of communication. Recommendations are made for a collaborative approach to achieving change.

In recent years it has become widely accepted that the natural systems on which we depend for survival are being degraded by human activity. It is no longer a question of if we need to reduce our impact upon the planet, but of the extent to which we need to change our behaviour, and how soon we need to act. Such change will depend upon the support of voters, governments, and the international community and will require wide spread changes in attitudes and behaviour. Using the social identity approach as a framework, the current programme of research focuses on rural land users in Australia and the effectiveness of sustainable land use campaigns directed at them from both urban and rural sources. The studies provide a novel contribution to the area by demonstrating the effects of intergroup threat on group-based communication, in particular, the perception of threat to rural identity and the effect on urban and rural messages aimed at changing land use behaviour. Conclusions about broader social influence processes were also made by assessing rural participants’ perceptions of the degree to which others are influenced. Although the studies are based in the context of rural Australian land users, the results and theoretical implications can be applied to any situation wherein one group is attempting to change the attitudes and behaviours of another group. This could range from local interest groups trying to convince each other of the merits of their ideas through to political parties and nations calling for united and decisive action on global issues. Such groups ignore issues of power and status at the risk of ineffective communications or even a backlash in opinion and behaviour. Six studies were conducted, including five survey studies with rural landholders and one experiment with students at a rural campus. Study 1 (N = 251) was an evaluation of sustainable land use campaigns in general, comparing those from urban sources to those from rural sources. Study 2 (N = 585) extended this by assessing the moderating role of intergroup threat perceptions. This study also measured the perceptions of influence of urban and rural messages on urban people and other rural people. Study 3 (N = 98) assessed the influence of an actual land use campaign delivered by an ingroup source on individuals’ attitudes and behaviours and the perceived influence on others. Study 4 (N = 249) built upon Study 2 but included additional measures to address some of the inconsistencies between Studies 1 and 2. To address the psychological underpinnings of group-based influence, Study 5 (N = 124) included measures of trust in urban and rural sources as well as reports of influence, agreement, and past behaviour. To conclude, Study 6 (N = 64) provided an experimental test of persuasion by manipulating the source of the message. Self-reported identification and intergroup threat were examined as moderators of group-based persuasion. Furthermore, attributions of constructiveness were explored as a possible reason for the superior influence of ingroups. Across the six studies it was found that ingroup messages were consistently more influential than outgroup messages. Attributions of trust and constructiveness helped to explain the superior influence of ingroups. In terms of perceptions of influence on others, there was a third-person effect for urban messages but rural people did not differentiate between themselves and other rural people in response to rural messages. Furthermore, rural identification was associated with greater reported influence from the ingroup source and perceived threat was associated with increased influence of rural messages compared to urban messages. These findings have clear implications for attempts at changing attitudes between groups, particularly where there is a salient and competitive intergroup context. Outgroups operate at a distinct disadvantage in delivering persuasive communications, especially if ingroup identification is high or there is a perception of threat stemming from the communicating group. Evidence of the persuasiveness of ingroups compared to outgroups is further strengthened by the perceptions of similarity in influence of rural sources for self and other ingroup members. The findings on trust and constructiveness hint at the possibility of overcoming barriers to outgroup persuasion if positive motives for the messages can be established. Of course, this depends on the severity of the intergroup context and the nature of communication. Recommendations are made for a collaborative approach to achieving change.

The return to the customary or integration of customary and statutory tenure systems to continue gain currency in both contemporary policy and academic discourses on land tenure as an alternative pathway towards enhancing security of access and tenure in the sub-Saharan African context. Central to the debates are issues concerning the relevance of customary land tenure arrangements and appropriate pathways to successfully engineer the process of harmonization toward improved tenure security whilst preserving of the communitarian principles of local tenure systems. Using two case studies in rural Ghana, this study investigated the prevailing land tenure arrangements, practices and socio-political dynamics that underpin them, highlighting the challenges and opportunities that need to be addressed for the successful adaptation of customary tenure rules and institutions into the statutory system towards improved tenure security and sustainable land management. The research employed a mixture of qualitative and quantitative methods including interviews, focus group discussions and questionnaires to collate and analyse data from sampled respondents in Kakum and Ankasa in southern Ghana. The results of the investigation revealed that contrary to the mainstream view that customary tenure arrangements are incapable of providing tenure security in the face on ongoing transformations, the perceived tenure security of respondents was generally high in the study areas. This notwithstanding, it was observed that the emerging patterns of access and control (occasioned by increasing land scarcity and commodification) have resulted in social differentiation and inequalities in land access and distribution amongst the poor and vulnerable members of the landholding groups including women and the youth. The research also showed that aside from tenure security, other important contextual factors including access to credit, modernised agricultural inputs and targeted extension service support significantly influence households' investment decisions regarding adoption of sustainable land management practices. These findings have far-reaching implications for current land tenure interventions aimed at harmonising customary and statutory tenure structures for improved tenure security and sustainable land management. Results of the investigation were used to develop a three-phase incremental framework on formalisation of customary land rights which could serve as bespoke framework to guide the design of land tenure intervention strategies and implementation towards addressing local tenure insecurity in the specific context of the study areas and sub-Saharan Africa generally. The major conclusion of the research is that balancing the market efficiency and social equity considerations is necessary and should be pursued under the ongoing land tenure reforms for inclusive and equitable outcomes at the local level. This derives from the fact that the existing tenurial challenges are complex and context-specific, equally requiring well-balanced and nuanced solutions to effectively address them.

Made available in DSpace on 2017-07-10T19:24:15Z (GMT). No. of bitstreams: 1 Suzana_ Costa Wrublack.pdf: 1543674 bytes, checksum: a147c806a7c505117131dbc0077215e4 (MD5) Previous issue date: 2016-02-12 / This research aimed to contribute to the monitoring of water quality using orbital remote sensing and GIS techniques, use and occupation of mapping land in Lontra river watershed, focusing on information to apply water resources management instruments. The first phase consisted on mapping the use and soil occupation and on evaluating quality of irrigation water used in Salto do Lontra municipality, in Paraná state, Brazil. SPOT-5 satellite images were used to carry out the supervised classification of the Maximum Likelihood algorithm ML. Water quality data were submitted to statistical analyses by the PCA and FA techniques, in order to identify the most relevant variables during the evaluation of irrigation water quality. The UCS characterization by maximum likelihood estimation allowed identifying the classes: agricultural crops, bare soil, forest and urban area. The PCA use concerning parameters of irrigation water quality explained 53.27% of variation in water quality according to the monitored points, represented by family-based farming. In a second phase, a variation of water quality was studied along Lontra river, with the support of Geographic Information Systems (GIS) integrated with multivariate statistical techniques to investigate the dependency relationships among variables responses associated with UCS. Mosaic images of 2014 from Google Earth were used to map such land use and occupation. Digital Elevation Model (DEM) and soil maps made up database, along with UCS categories, defined as explanatory variables. The definition of areas of influence by Thiessen polygon method and multivariate statistics techniques, especially the Redundancy Analysis (RDA), were used to investigate correlation among explanatory variables (land use and occupation, slope, soil types and monitoring points) in parameters such as water quality, defined as exploratory variables. Land use mapping and Linear Redundancy Analysis allowed the identification of anthropogenic pressures on water quality parameters, especially when compared to points located by upstream and downstream of Lontras s river watershed. Finally, an approach concerning the use of Geotechnologies on the study of environmental issues was carried out focusing the contribution of information to apply water resources management instruments. The UCS characterization, using SAM supervised classification and Landsat-8 image, defined five UCS categories that with different seasons and monitoring points (upstream and downstream watershed) investigated the correlation among these variables and water quality parameters. RDA identified positive correlation among dependent variables (electrical conductivity and total dissolved solids) and warmer seasons (fall, spring and summer). The highest answers of temperature and pH were positively related to land use especially in the categories of forest, water and pasture. Temporary crops and urban areas showed negative correlation to other UCS categories. The correlation of turbidity and reducing oxidation potential parameters, especially during the winter season. Geotechnologies used in this trial, especially represented by geoprocessing and GIS, have allowed the study of geographical space structure and environmental aspects. Multivariate statistical methods enabled the synthesis of data variability structure and identification of the most significant variables, especially to the seasons and different monitoring points along the Lontra river watershed. This research mainly focused on irrigated family farming, where subsidies have been raised to assist with management decision-making on water use and the development of actions in the application of available rational technologies, aiming at improving different water use systems. Remote sensing techniques combined with GIS have contributed to carry out studies concerning management of territories and, in particular, water resources management. / Este trabalho teve por objetivo contribuir a partir de técnicas ligadas ao Sensoriamento Remoto Orbital e SIG, no monitoramento da qualidade da água, mapeamento do uso e ocupação do solo na microbacia do rio Lontra, com foco na contribuição de informações para aplicação dos instrumentos de gestão dos recursos hídricos. Em uma primeira análise, realizaram-se o mapeamento do Uso e Ocupação do Solo (UCS) e a avaliação da qualidade da água utilizada para irrigação no município de Salto do Lontra, Estado do Paraná. Imagens do satélite SPOT-5 foram utilizadas para realizar a classificação supervisionada pelo algoritmo de Máxima Verossimilhança MAXVER. Os dados de qualidade da água foram submetidos às análises estatísticas pelas técnicas de Análise de Componentes Principais (ACP) e Análise Fatorial (AF), para a identificação das variáveis mais relevantes na avaliação da qualidade da água de irrigação. A caracterização do UCS pelo classificador MAXVER permitiu a identificação das classes: culturas agrícolas, solo exposto/resteva, mata e área urbana. A aplicação da ACP dos parâmetros de qualidade da água de irrigação explicou 53,27% da variação da qualidade da água entre os pontos monitorados, representados pelas propriedades rurais de base familiar. Em um segundo momento, a variação da qualidade da água foi estudada ao longo do rio Lontra, com o apoio dos Sistemas de Informações Geográficas (SIG) integradas às técnicas estatísticas multivariadas para a averiguação das relações de dependência entre as variáveis respostas associadas ao UCS. Foram utilizadas imagens mosaicadas datadas do ano 2014, provenientes do Google Earth para o mapeamento de uso e ocupação do solo. O Modelo Digital de Elevação (MDE) e os mapas de tipos de solos serviram para compor o banco de dados, juntamente com as categorias de UCS, definidos como variáveis explicativas. A definição das áreas de influência pela técnica de polígonos de Thiessen e as técnicas estatísticas multivariadas, em especial à Análise de Redundância (RDA) foram utilizadas para investigação da correlação entre as variáveis explicativas (UCS, declividade, tipos de solos e pontos de monitoramento) nos parâmetros de qualidade da água, definidas como variáveis exploratórias. O mapeamento do UCS e a Análise de Redundância Linear RDA possibilitaram a identificação das pressões antrópicas sobre os parâmetros de qualidade da água, especialmente quando comparado aos pontos situados a montante e a jusante da microbacia do rio Lontra. Finalmente, foi conduzida uma abordagem acerca da utilização das Geotecnologias no estudo do espaço ambiental, com foco na contribuição de informações para aplicação dos instrumentos de gestão dos recursos hídricos. A caracterização do UCS, mediante a Classificação Supervisionada SAM da imagem Landsat- 8, possibilitou a definição de cinco categorias de UCS, que junto às distintas estações do ano e pontos de monitoramento (a montante e a jusante da microbacia) buscaram investigar a correlação destas variáveis com os parâmetros de qualidade da água. Pela RDA, identificou-se a correlação positiva para as variáveis dependentes (condutividade elétrica e sólidos totais dissolvidos) relacionadas com as estações mais quentes (outono, primavera e verão). Valores mais elevados de temperatura e pH estiveram positivamente relacionados aos usos do solo especialmente nas categorias de mata, água e pastagens. As culturas temporárias e área urbana demonstraram estar negativamente correlacionadas às demais categorias de UCS. A correlação dos parâmetros de turbidez e potencial redutor de oxidação, principalmente na estação do inverno. As geotecnologias utilizadas neste trabalho, especialmente representadas pelas técnicas de geoprocessamento e dos SIG s, possibilitaram o estudo da estrutura do espaço geográfico e dos aspectos ambientais. Os métodos estatísticos multivariados possibilitaram a sintetização da estrutura de variabilidade dos dados e a identificação das variáveis mais significativas, com destaque às estações do ano e aos distintos pontos de monitoramento ao longo da microbacia do rio Lontra. A viii aplicação conjunta de técnicas de sensoriamento remoto orbital e SIG contribuiu para condução de estudos voltados a gestão dos territórios e em especial à gestão dos recursos hídricos. A pesquisa teve como foco principal a agricultura familiar irrigada, em que foram levantados subsídios que pudessem auxiliar nas decisões gerenciais sobre o uso da água e no desenvolvimento de ações para a aplicação de tecnologias racionais disponíveis, visando à melhoria

Made available in DSpace on 2017-05-12T14:47:33Z (GMT). No. of bitstreams: 1 Suzana_ Costa Wrublack.pdf: 1543674 bytes, checksum: a147c806a7c505117131dbc0077215e4 (MD5) Previous issue date: 2016-02-12 / This research aimed to contribute to the monitoring of water quality using orbital remote sensing and GIS techniques, use and occupation of mapping land in Lontra river watershed, focusing on information to apply water resources management instruments. The first phase consisted on mapping the use and soil occupation and on evaluating quality of irrigation water used in Salto do Lontra municipality, in Paraná state, Brazil. SPOT-5 satellite images were used to carry out the supervised classification of the Maximum Likelihood algorithm ML. Water quality data were submitted to statistical analyses by the PCA and FA techniques, in order to identify the most relevant variables during the evaluation of irrigation water quality. The UCS characterization by maximum likelihood estimation allowed identifying the classes: agricultural crops, bare soil, forest and urban area. The PCA use concerning parameters of irrigation water quality explained 53.27% of variation in water quality according to the monitored points, represented by family-based farming. In a second phase, a variation of water quality was studied along Lontra river, with the support of Geographic Information Systems (GIS) integrated with multivariate statistical techniques to investigate the dependency relationships among variables responses associated with UCS. Mosaic images of 2014 from Google Earth were used to map such land use and occupation. Digital Elevation Model (DEM) and soil maps made up database, along with UCS categories, defined as explanatory variables. The definition of areas of influence by Thiessen polygon method and multivariate statistics techniques, especially the Redundancy Analysis (RDA), were used to investigate correlation among explanatory variables (land use and occupation, slope, soil types and monitoring points) in parameters such as water quality, defined as exploratory variables. Land use mapping and Linear Redundancy Analysis allowed the identification of anthropogenic pressures on water quality parameters, especially when compared to points located by upstream and downstream of Lontras s river watershed. Finally, an approach concerning the use of Geotechnologies on the study of environmental issues was carried out focusing the contribution of information to apply water resources management instruments. The UCS characterization, using SAM supervised classification and Landsat-8 image, defined five UCS categories that with different seasons and monitoring points (upstream and downstream watershed) investigated the correlation among these variables and water quality parameters. RDA identified positive correlation among dependent variables (electrical conductivity and total dissolved solids) and warmer seasons (fall, spring and summer). The highest answers of temperature and pH were positively related to land use especially in the categories of forest, water and pasture. Temporary crops and urban areas showed negative correlation to other UCS categories. The correlation of turbidity and reducing oxidation potential parameters, especially during the winter season. Geotechnologies used in this trial, especially represented by geoprocessing and GIS, have allowed the study of geographical space structure and environmental aspects. Multivariate statistical methods enabled the synthesis of data variability structure and identification of the most significant variables, especially to the seasons and different monitoring points along the Lontra river watershed. This research mainly focused on irrigated family farming, where subsidies have been raised to assist with management decision-making on water use and the development of actions in the application of available rational technologies, aiming at improving different water use systems. Remote sensing techniques combined with GIS have contributed to carry out studies concerning management of territories and, in particular, water resources management. / Este trabalho teve por objetivo contribuir a partir de técnicas ligadas ao Sensoriamento Remoto Orbital e SIG, no monitoramento da qualidade da água, mapeamento do uso e ocupação do solo na microbacia do rio Lontra, com foco na contribuição de informações para aplicação dos instrumentos de gestão dos recursos hídricos. Em uma primeira análise, realizaram-se o mapeamento do Uso e Ocupação do Solo (UCS) e a avaliação da qualidade da água utilizada para irrigação no município de Salto do Lontra, Estado do Paraná. Imagens do satélite SPOT-5 foram utilizadas para realizar a classificação supervisionada pelo algoritmo de Máxima Verossimilhança MAXVER. Os dados de qualidade da água foram submetidos às análises estatísticas pelas técnicas de Análise de Componentes Principais (ACP) e Análise Fatorial (AF), para a identificação das variáveis mais relevantes na avaliação da qualidade da água de irrigação. A caracterização do UCS pelo classificador MAXVER permitiu a identificação das classes: culturas agrícolas, solo exposto/resteva, mata e área urbana. A aplicação da ACP dos parâmetros de qualidade da água de irrigação explicou 53,27% da variação da qualidade da água entre os pontos monitorados, representados pelas propriedades rurais de base familiar. Em um segundo momento, a variação da qualidade da água foi estudada ao longo do rio Lontra, com o apoio dos Sistemas de Informações Geográficas (SIG) integradas às técnicas estatísticas multivariadas para a averiguação das relações de dependência entre as variáveis respostas associadas ao UCS. Foram utilizadas imagens mosaicadas datadas do ano 2014, provenientes do Google Earth para o mapeamento de uso e ocupação do solo. O Modelo Digital de Elevação (MDE) e os mapas de tipos de solos serviram para compor o banco de dados, juntamente com as categorias de UCS, definidos como variáveis explicativas. A definição das áreas de influência pela técnica de polígonos de Thiessen e as técnicas estatísticas multivariadas, em especial à Análise de Redundância (RDA) foram utilizadas para investigação da correlação entre as variáveis explicativas (UCS, declividade, tipos de solos e pontos de monitoramento) nos parâmetros de qualidade da água, definidas como variáveis exploratórias. O mapeamento do UCS e a Análise de Redundância Linear RDA possibilitaram a identificação das pressões antrópicas sobre os parâmetros de qualidade da água, especialmente quando comparado aos pontos situados a montante e a jusante da microbacia do rio Lontra. Finalmente, foi conduzida uma abordagem acerca da utilização das Geotecnologias no estudo do espaço ambiental, com foco na contribuição de informações para aplicação dos instrumentos de gestão dos recursos hídricos. A caracterização do UCS, mediante a Classificação Supervisionada SAM da imagem Landsat- 8, possibilitou a definição de cinco categorias de UCS, que junto às distintas estações do ano e pontos de monitoramento (a montante e a jusante da microbacia) buscaram investigar a correlação destas variáveis com os parâmetros de qualidade da água. Pela RDA, identificou-se a correlação positiva para as variáveis dependentes (condutividade elétrica e sólidos totais dissolvidos) relacionadas com as estações mais quentes (outono, primavera e verão). Valores mais elevados de temperatura e pH estiveram positivamente relacionados aos usos do solo especialmente nas categorias de mata, água e pastagens. As culturas temporárias e área urbana demonstraram estar negativamente correlacionadas às demais categorias de UCS. A correlação dos parâmetros de turbidez e potencial redutor de oxidação, principalmente na estação do inverno. As geotecnologias utilizadas neste trabalho, especialmente representadas pelas técnicas de geoprocessamento e dos SIG s, possibilitaram o estudo da estrutura do espaço geográfico e dos aspectos ambientais. Os métodos estatísticos multivariados possibilitaram a sintetização da estrutura de variabilidade dos dados e a identificação das variáveis mais significativas, com destaque às estações do ano e aos distintos pontos de monitoramento ao longo da microbacia do rio Lontra. A viii aplicação conjunta de técnicas de sensoriamento remoto orbital e SIG contribuiu para condução de estudos voltados a gestão dos territórios e em especial à gestão dos recursos hídricos. A pesquisa teve como foco principal a agricultura familiar irrigada, em que foram levantados subsídios que pudessem auxiliar nas decisões gerenciais sobre o uso da água e no desenvolvimento de ações para a aplicação de tecnologias racionais disponíveis, visando à melhoria

Drylands cover about 40% of the earth’s land surface and provide the basis for the livelihoods of 38% of the global human population. Worldwide, these ecosystems are prone to heavy degradation. Increasing levels of dryland degradation result a strong decline of ecosystem services. In addition, in highly variable semi-arid environments changing future environmental conditions will potentially have severe consequences for productivity and ecosystem dynamics. Hence, global efforts have to be made to understand the particular causes and consequences of dryland degradation and to promote sustainable management options for semi-arid and arid ecosystems in a changing world. Here I particularly address the problem of semi-arid savanna degradation, which mostly occurs in form of woody plant encroachment. At this, I aim at finding viable sustainable management strategies and improving the general understanding of semi-arid savanna vegetation dynamics under conditions of extensive livestock production. Moreover, the influence of external forces, i.e. environmental change and land reform, on the use of savanna vegetation and on the ecosystem response to this land use is assessed. Based on this I identify conditions and strategies that facilitate a sustainable use of semi-arid savanna rangelands in a changing world. I extended an eco-hydrological model to simulate rangeland vegetation dynamics for a typical semi-arid savanna in eastern Namibia. In particular, I identified the response of semi-arid savanna vegetation to different land use strategies (including fire management) also with regard to different predicted precipitation, temperature and CO2 regimes. Not only environmental but also economic and political constraints like e.g. land reform programmes are shaping rangeland management strategies. Hence, I aimed at understanding the effects of the ongoing process of land reform in southern Africa on land use and the semi-arid savanna vegetation. Therefore, I developed and implemented an agent-based ecological-economic modelling tool for interactive role plays with land users. This tool was applied in an interdisciplinary empirical study to identify general patterns of management decisions and the between-farm cooperation of land reform beneficiaries in eastern Namibia. The eco-hydrological simulations revealed that the future dynamics of semi-arid savanna vegetation strongly depend on the respective climate change scenario. In particular, I found that the capacity of the system to sustain domestic livestock production will strongly depend on changes in the amount and temporal distribution of precipitation. In addition, my simulations revealed that shrub encroachment will become less likely under future climatic conditions although positive effects of CO2 on woody plant growth and transpiration have been considered. While earlier studies predicted a further increase in shrub encroachment due to increased levels of atmospheric CO2, my contrary finding is based on the negative impacts of temperature increase on the drought sensitive seedling germination and establishment of woody plant species. Further simulation experiments revealed that prescribed fires are an efficient tool for semi-arid rangeland management, since they suppress woody plant seedling establishment. The strategies tested have increased the long term productivity of the savanna in terms of livestock production and decreased the risk for shrub encroachment (i.e. savanna degradation). This finding refutes the views promoted by existing studies, which state that fires are of minor importance for the vegetation dynamics of semi-arid and arid savannas. Again, the difference in predictions is related to the bottleneck at the seedling establishment stage of woody plants, which has not been sufficiently considered in earlier studies. The ecological-economic role plays with Namibian land reform beneficiaries showed that the farmers made their decisions with regard to herd size adjustments according to economic but not according to environmental variables. Hence, they do not manage opportunistically by tracking grass biomass availability but rather apply conservative management strategies with low stocking rates. This implies that under the given circumstances the management of these farmers will not per se cause (or further worsen) the problem of savanna degradation and shrub encroachment due to overgrazing. However, as my results indicate that this management strategy is rather based on high financial pressure, it is not an indicator for successful rangeland management. Rather, farmers struggle hard to make any positive revenue from their farming business and the success of the Namibian land reform is currently disputable. The role-plays also revealed that cooperation between farmers is difficult even though obligatory due to the often small farm sizes. I thus propose that cooperation needs to be facilitated to improve the success of land reform beneficiaries. / Semiaride (halbtrockene) Savannen bedecken große Teile der Erdoberfläche und sichern die Lebensgrundlage von vielen Millionen Menschen. Die häufigste Form der Landnutzung in diesen Trockengebieten ist die Produktion von Vieh in extensiver Weidelandbewirtschaftung. In Folge klimatischer Veränderungen und als Konsequenz aus der teils intensiven Beweidung dieser Trockengebiete kommt es häufig zur Degradierung derselben in Form einer Zunahme von ‚unerwünschter‘ holziger Vegetation auf Kosten von futterverwertbaren Gräsern. Dieser als Verbuschung bezeichnete Prozess hat schwere negative Auswirkungen auf die betroffenen Ökosysteme und ist die Ursache für einen zunehmenden Rückgang der ökonomischen Leistungsfähigkeit der betroffenen Betriebe. In meiner Dissertation befasse ich mich mit den Auswirkungen von Klimawandel und politischen Veränderungen auf die Savannenvegetation im südlichen Afrika und auf die Möglichkeiten für die Nutzung dieser Ökosysteme in Form von Viehwirtschaft. Hierbei möchte ich sowohl das allgemeine Verständnis der ökologischen Zusammenhänge verbessern, als auch Strategien für die nachhaltige Nutzung der Savannen identifizieren und bewerten. Da nicht nur ökologische, sondern auch ökonomische und politische Einflussfaktoren, wie zum Beispiel die umfangreichen Landumverteilungen im Rahmen der Bodenreform im südlichen Afrika auf die tatsächliche Landnutzung wirken, habe ich im Rahmen der Dissertation zudem untersucht, nach welchen Umwelt und Kapitalvariablen sich die Farmer, welche Ihr Land im Rahmen der Bodenreform zugeteilt bekommen haben, bei Ihren Entscheidungen richten. Methodisch verwende ich verschiedene Simulationsmodelle, welche zur Untersuchung der langfristigen Veränderungen von verschiedensten Szenarien (Klimawandel, Landnutzung) geeignet sind. Hierbei habe ich teilweise bestehende Modelle angepasst, aber auch ein neues Modell, welches zur Befragung von Farmern in Namibia verwendet wurde, entwickelt. Meine Dissertation führt im Wesentlichen zu vier Erkenntnissen: Erstens, zeigen meine Ergebnisse, welche große Bedeutung die spezifischen ökologischen Eigenschaften der Bäume und Sträucher in semiariden Savannen für die Vorhersage der Entwicklung dieser Systeme unter Klimawandel hat. Hierbei zeigte sich, dass insbesondere die Sensitivität der Keimlinge gegenüber Trockenheit und Feuer eine entscheidende Rolle spielt. Daraus folgt die zweite wesentliche Erkenntnis: Feuer eignet sich in herausragender Weise, um halbtrockene Savannen vor der Verbuschung zu bewahren. Drittens haben die Rollenspiele mit Farmern in Namibia gezeigt, dass deren Entscheidungen im Wesentlichen von finanziellen Schwierigkeiten und nicht von Umwelteinflüssen getrieben werden. Dennoch zeigten meine Ergebnisse, dass diese Farmer mit Ihrem derzeitigen Verhalten wahrscheinlich nicht zur weiteren Degradierung der Savannenvegetation beitragen. Die vierte, und mit am bedeutendste Erkenntnis aus meiner Arbeit ist, dass konservative Beweidungsstrategien mit geringen und konstanten Viehdichten notwendig sind um semiaride Savannen dauerhaft in ökologisch und ökonomisch nachhaltiger Weise zu Nutzen.

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