Este estudo objetivou avaliar o efeito das mudanças no uso e cobertura do solo nos últimos 37 anos (1972 a 2008) na resposta hidrológica da bacia do rio Piracicaba, SP. As principais mudanças de uso e cobertura do solo na bacia neste período foram aumento da área urbana, redução da área de pastagem e aumento do plantio de canade- açúcar. Além disso, a bacia conta com uma peculiaridade, que é a presença do Sistema Cantareira, que desvia água à região metropolitana de São Paulo (RMSP), desde 1974. Foi utilizado o Modelo Hidrológico de Grandes Bacias (MGB), que tem a vantagem de avaliar de forma distribuída a variação da cobertura, do tipo e uso do solo, além da própria propagação no escoamento. O modelo foi ajustado à bacia do rio Piracicaba (área de 12.245 km2) para simulação de vazões diárias. Para o processo de ajuste do modelo foram utilizados dados diários de 1972 a 2008, de 12 postos fluviométricos, 61 pluviométricos e 20 meteorológicos, modelo numérico do terreno, mapas de solos e uso e cobertura do solo (para os anos: 1978, 1983, 1985, 1997 e 2003), e parâmetros que são importantes para diferenciar tipos de solo e usos e coberturas do solo. O processo de simulação das vazões foi realizado em duas etapas: calibração dos parâmetros (entre 1972 a 1990) e verificação (1991 a 2008). Para avaliação da qualidade de ajuste foi considerada a análise visual dos hidrogramas (vazões observadas e calculadas) e os valores das funções objetivo (R2, Rlog e V). Foi realizada uma análise de sensibilidade de cada parâmetro, a fim de verificar a influência de cada um. Os resultados mostram um bom ajuste entre as vazões diárias observadas e calculadas pelo modelo. Os melhores resultados das funções objetivo foram obtidos para as sub-bacias de maior área de drenagem. O Sistema Cantareira exerce forte influência na simulação das vazões diárias. As análises de sensibilidade dos parâmetros revelam que os resultados da simulação do modelo são extremamente sensíveis às variações dos parâmetros: capacidade de armazenamento de água no solo (Wm); parâmetro de forma da relação entre o armazenamento e saturação (b); parâmetros de drenagem subterrânea (KBAS) e sub-superficial (KINT); albedo e resistência superficial (rS). Cenários alternativos em relação às mudanças no uso e cobertura do solo foram testados e comparados a simulação do cenário atual da bacia do rio Piracicaba no período entre 1972 e 2008. Comparando o cenário atual ao cenário em que não ocorreu nenhuma alteração na bacia a partir de 1972, verificou-se uma redução das vazões: máxima de 2,5 m3/s; mínima de 2,1 m3/s; e média de 1,9 m3/s. Outros cenários alternativos foram testados e comparados ao cenário atual e foi verificado um aumento da vazão média de 17,2 m3/s para cenário de 100% agricultura; e maior redução da vazão média de 3,9 m3/s para o cenário de conversão da agricultura para pastagem. / This study aimed at to evaluate the effect of changes in land use and land cover over the last 37 years (1972 to 2008) on the hydrological response in the Piracicaba river basin, SP. The main changes in the land use and land cover in the basin over that period were the increase in the urban area, decrease in the pasture area, and increase in the sugarcane plantations. Moreover, the basin has a peculiarity, which is the presence of the Cantareira System, which diverts water to the metropolitan region of São Paulo (RSMP), since 1974. We used a hydrological model of Great Basin (MGB), which has the advantage of evaluating in the distributed form, the variation of the land use/land cover, besides the flow propagation. The model was adjusted to the Piracicaba river basin (12,245 Km2 in area) to simulate daily streamflow. Daily data, from 1972 to 2008, were used for the process of model fitting, from 12 streamflow stations, 61 rainfall and 20 meteorological, digital terrain model, maps of soils and land use and land cover (for the years 1978, 1983, 1985, 1997 and 2003), and parameters that are important to differentiate soil types and uses and land cover. The process of simulation of the streamflow was carried out in two stages: calibration of parameters (from 1972 to 1990) and verification (1991 to 2008). To assess the quality of fitting it was considered the visual analysis of the hydrographs (observed and calculated streamflows) and the values of objective functions (R2, Rlog and V). We performed a sensitivity analysis of each parameter, in order to verify the influence of each one. The results showed a good fitting between the daily observed and calculated streamflows. The best results of the objective functions were obtained for the sub-basins of larger drainage area. The Cantareira System strongly influences the simulation of daily streamflow. Sensitivity analysis of parameters revealed that the simulation results of the model are extremely sensitive to variations of the parameters: soil water storage capacity (Wm), form parameter of the relationship between storage and saturation (b), parameters of drainage underground (KBAS) and subsurface (KINT), albedo and surface resistance (rS). Alternative scenarios for changes in the land use and land cover were tested and compared the simulation of the scenario actual of Piracicaba river basin in the period between 1972 and 2008. Comparing the scenario with no changes in the basin since 1972 to the actual scenario, a reduction in streamflow was detected: maximum of 2,5 m3/s, minimum of 2,1 m3/s, and an average of 1,9 m3/s. Other scenarios were tested and compared to the actual scenario, and it was detected an increase of the mean streamflow of 17,2 m3/s for scenario 100% of agriculture, and a decrease of the mean streamflow of 3,9 m3/s for the scenario of conversion from agriculture into pasture.

Savanna woodlands are vitally important in providing ecological services (e.g. erosion protection, micro-climate) and economic services (e.g. timber, food, fodder non-wood products, and wild-life habitats) that sustain local livelihoods and national economies. Increasing demands and the need for sustainable savanna woodland resource management requires that the ecological, economic, social and cultural values of these resources be explored and brought to the attention of decision makers and the general public. The identification and better understanding of the structure and dynamics of woodland community types, patterns of species distribution and quantitative properties of their diversity is important to the conservation and sustainable management of these woodlands. This study seeks to contribute to a better understanding of Nakasongola woodland community types, species diversity patterns and environment correlates, natural regeneration processes (i.e. sprouting and seedling establishment) and identifying livelihood strategies adopted by households, woody species utilised, and the contribution of charcoal production to household livelihoods. Data on vegetation and environmental variables were collected using 75 rectangular 20 x 50 m (0.1 ha) plots. Data on land use and land cover changes, and relevant associated socio-economic parameters were collected through the analysis of multi-temporal satellite imagery and field observations, as well as interviews of local households and key informants. The basic major livelihood activities for the rural households in this savanna dryland are charcoal production, subsistence crop cultivation and livestock grazing. However, it, sometimes, includes various combinations of activities, i.e. charcoal production and subsistence crop cultivation for both food and cash, and livestock keeping for income generation through selling the livestock products such as milk and, sometimes, the whole animal. At least 24 woody species, including fruit trees (Mangifera indica and Artocarpus heterophyllus), are frequently harvested, including 16 species that are considered the most utilized for charcoal production. Charcoal production, being the major source of income to the rural households, contributes on average US$ 259 ± 46 (S.E.) per household annually. There were significant differences in charcoal production (Kruskal-Wallis; H = 31.42, p < 0.0001), producer sale prices per bag of charcoal (H = 35.62, p < 0.0001), and annual incomes from charcoal production (H = 32.44, p < 0.0001) per households across the 8 sub-counties. Most of the youth (≤ 20 years old) derive their livelihoods from charcoal production, a small amount of trade, offering labour services, livestock keeping, fishing, bee keeping and earth brick making. Charcoal production, livestock keeping and hunting are carried out particularly by men, whereas, crop cultivation, and collection of fire wood, medicinal plants and fruits are carried out, mainly, by women. However, men are also engaged in cultivation only during the rainy seasons. There have been significant land cover changes in the area during the period 1984 to 2001, resulting in a 64% decrease in dense woodland cover, and an 80% increase in areas under cultivation/settlements. These changes are attributed to significant spatial expansion in agriculture increased commercialisation of charcoal production, grazing and human population growth. A total of 44,195 (5,893 plants/ha) woody plants representing 99 species in 67 genera and 31 families were recorded. The most species rich families were Mimosaceae (13), Rubiaceae (9), Moraceae (7), Euphorbiaceae (7), Anacardiaceae (6), Combretaceae (5) and Verbenaceae (5). Density of woody species differed significantly (F2, 72 = 6.3, P < 0.003) among land uses, being higher under charcoal production (7,131 ± 755 plants/ha) and cultivation (6,612 ± 665) areas and significantly lower under grazing lands (4,152 ± 525). Community species composition differed significantly (Global RANOSIM = 0.14, p = 0.001) among land use types. All measures of beta-diversity (spatial “turnover” in species composition) showed consistently higher beta-diversity in the grazing land use (βW = 3.1; βT = 3.1), followed by cultivation (βW = 2.8; βT = 3.0) and charcoal production (βW = 2.7; βT = 2.8), suggesting a more heterogeneous spatial distribution of species in the grazing lands. This suggests that variations in the composition and diversity of woody species are to a great extent influenced by land use type and anthropogenic disturbances in this region. Basal area of woody species differed significantly (F2, 72 = 12.0, P < 0.0001) among land uses, being highest under cultivation and charcoal production and significantly lower under grazing. Woody plant density differed (F2,72 = 6.3, P = 0.003) across landuses, being highest under charcoal production and cultivation and significantly lower under grazing. The species that contributed most to both basal area and density across all the land uses were Combretum collinum and Combretum molle. However, different species contributed the next most i.e. Piliostigma thonningii for grazing; Albizia zygia and Harrisonia abyssinica for cultivation and Vepris nobilis for charcoal production areas. For both basal area and abundance of all woody species, the total variance in species-environmental factor relations (for the combined first four canonical axes) was higher than 50%, suggesting a relatively strong influence of the measured environment variables on species composition and distributions. The CCA points to a significant influence of soil Ca2+ and Mg2+ in association with grazing on gradients in the composition and structure of woody species in the savanna woodland of Nakasongola. Resprouting was generally common among the woody species. A total of 2,595 stumps, representing 74 species in 31 families were recorded from all plots. Of these, 98.3% resprouted and were identified to species level. Density of both stumps and total resprout differed significantly (p < 0.05) among the land uses, being higher in charcoal production areas than in grazing and cultivation land uses. For the overall pooled data, resprouts per stump differed significantly among land uses (F2, 456 = 7.75, p = 0.0005), being highest in charcoal production (mean ± S.E.; 14 ± 1) and cultivation (13 ± 1) land uses and lowest under grazing areas (10 ± 1). Generally, the mean number of resprouts per stump increased with increasing stump basal diameter (BD), being highest for BD size class > 41 cm. In relation to stump height, the highest mean resprouts/stump was found on stumps with heights ranging from 0.31- 0.40 m. Based on pooled species data, regression analyses showed weakly significant negative relationships between BD of leading resprouts and number of resprouts/stump (r2 = 0.123, p < 0.0001) and between height of leading resprouts and number of resprouts/stump (r2 = 0.068, p < 0.0001). Density of seedlings of woody species differed significantly among land use types (ANOVA; F2, 72 =5.9, p = 0.004), being highest for cultivation (3,162 ± 440 individuals ha-1), followed by charcoal production (2,416 ± 295 ha-1) and lowest for grazing (1,629 ± 205 ha-1). Composition of seedlings differed significantly among land use types (Global RANOSIM = 0.119, p = 0.001). The distributions and densities of some seedlings were explained by gradients in environmental variables, with edaphic factors (i.e. Ca2+, Mg2+, K+ and organic matter) and charcoal production being the most important. The first two axes of the Canonical Correspondence Analysis (CCA) explained 41.9% of the variance in species – environmental relations and were a reflection of edaphic and charcoal production land use gradients. All of the 16 highly utilized species were well represented in both the juvenile and adult classes, with gradually declining number of individuals with increasing stem size-class. This indicates that most of these species have high regeneration potential. Juvenile:adult tree ratios >1 and negative DSCD slopes indicate good recruitment and probably successful regeneration for these species. The study revealed land cover changes mainly in the dense and medium dense woodlands, reflected by the increase in open woodland, grasslands and cultivation/settlements. These trends threaten the livelihoods of local communities who are entirely dependent on these natural resources. Sustainable management will require the establishment of suitable integrated community-based institutions and management practices, with support from all key stakeholders (i.e. National Forest Authority (NFA)) and local communities. Maintenance of savanna woodland resources and other ecosystem services essential for human well-being will require an effective legal framework to prevent over-exploitation and give incentives for the protection of the fragile savanna woodland vegetation. An appropriate savanna woodland management policy will be required to guide changes in land use that accommodate the requirements of land users, aided by targeted conservation efforts to all woody plants and particularly for the highly utilized species for charcoal production as well as the multipurpose species. In addition, there is urgent need to build local capacity for improved harvesting and utilization of these tree species. This can be achieved through equipping local users with up to date information as well as observing the existing skills.

A região do médio rio Araguaia está localizada em uma área de transição entre a Floresta Tropical e o Cerrado, região esta que vem sofrendo um intenso processo de desmatamento nas últimas décadas. Contudo, a quantificação e os impactos destas alterações são ainda pouco conhecidos. Portanto, este estudo teve como objetivo avaliar a dinâmica temporal das alterações na estrutura da paisagem na bacia do médio Araguaia, entre 1975 e 2007, e os fatores relacionados a estas alterações. O capítulo 1 apresenta uma contextualização científica desta pesquisa. Os outros 4 capítulos apresentam manuscritos que serão submetidos a publicação. O capítulo 2 analisa as alterações no uso e cobertura da terra na região do Parque Estadual do Cantão (Tocantins) para um período de 19 anos, entre 1981 e 2000. Nossos resultados mostraram que a redução da vegetação nativa e conseqüente aumento de áreas agropastoris está associada ao aumento da fragmentação. Observamos também uma baixa conversão da vegetação nativa no interior do parque. No entanto, estes baixos valores podem estar associados à localização da reserva, dentro da planície de inundação do rio Araguaia. O capítulo 3 mostra os resultados do mapeamento do uso e cobertura do solo para o médio Araguaia nos anos de 1975, 1985, 1996 e 2007. Para tal, foi utilizado o método de classificação híbrida. O mapeamento apresentou uma acurácia geral de 85%. A extensão da área perdida das três classes de cobertura nativa (floresta, cerrado aberto e cerrado stricto), ao longo destes 32 anos analisados, totaliza uma redução de 26% destas coberturas. Os resultados dos efeitos destas mudanças na estrutura e configuração da paisagem são apresentados no capítulo 4. A análise da composição mostrou que, áreas de floresta e cerrado stricto foram as mais afetadas pelas conversões. Em relação à configuração da paisagem, foi verificada uma considerável redução no tamanho do maior fragmento, principalmente de floresta, que foi acompanhado do aumento no número de pequenos fragmentos. Por sua vez, esta apresenta uma relação com o aumento da densidade de borda, diminuição das áreas centrais médias e aumento da distância entre os fragmentos, resultado que mostra um elevado índice de fragmentação da vegetação nativa remanescente. Por fim, no capítulo 5, apresentamos os resultados sobre os remanescentes de cobertura nativa em 2007. Dos 166 mil km² da área estudada, 86.808 km² eram de vegetação primária em 2007. Com isso foi realizada uma análise de regressão logística para identificar a influência da distância de estradas, distância de cidades, declividade do terreno, situação fundiária, fertilidade do solo e ocorrência de alagamento no processo de desmatamento. Valores significativos (p<0,05) mostram que o distanciamento de estradas e cidades, o aumento da declividade, a presença de unidades de conservação de proteção integral, terras indígenas, áreas alagáveis e áreas com baixa fertilidade apresentam influência positiva para a presença e manutenção de áreas primárias. A análise destes processos é muito importante para um melhor entendimento da dinâmica regional de uso do solo, além de fornecer informações de apoio para um planejamento regional mais eficiente e sustentável. / The central region of the Araguaia river basin encompasses a transition area between the Tropical Rain Forest and the Cerrado in Brazil. Despite of the fact that during the last four decades, this area has undergone an intense deforestation process, the quantification and impact of these changes are still unknown. Thus this study aimed to evaluate the dynamics of changes in landscape structure in the middle Araguaia river basin; and the driving factors of such changes.Chapter 1 of this thesis introduces the scientific contextualization of this research. The other 4 chapters present manuscripts to be submitted for publication. Chapter 2 analyzes the land use and land cover changes in the Cantão State Park region, Tocantins, for a period of 19 years, from 1981 to 2000. Our findings showed that the reduction of native vegetation and consequent increase of agricultural and pasture areas were related to the increase of fragmentation. We observed low conversion of native vegetation inside of the park area. However, these low rates of native vegetation losses may be associated with the geographical location of the reserve within the Araguaias floodplain.Chapter 3 present the results of the land use and land cover mapping of the middle Araguaia region for 1975, 1985, 1996 and 2007. To derive these maps, a hybrid classification method was implemented. The mapping showed an overall accuracy of 85%. The extent of native cover (forest, open cerrado and cerrado stricto) changes over the 32 years totalized a reduction of 26% of these land covers. The results of the effects of these changes in landscape structure and configuration were evaluated in Chapter 4. Our analysis of landscape composition showed that areas of forest and cerrado stricto were the most affected by conversions. Regarding the landscape configuration, there was a considerable reduction in the largest patch index, mainly of forest, which was followed by an increase in the number of small patches, which in turn was related to the increase of edge density, decrease of core areas and increase in the mean patch distance. These results indicate a high degree of fragmentation of remaining native vegetation.Finally, Chapter 5 analyzes the native vegetation cover remnants in 2007. Of the 166,000 km² of the study area, 86,808 km² were remnants of primary vegetation. Then, we performed a logistic regression analysis to identify the influence of distance from roads, distance from cities, slope, land tenure, fertility and the occurrence of flooding in the deforestation process. Significant values (p <0.05) for all variables were obtained, showing that the distance from roads and cities, slope increase, presence of conservation units, indigenous lands, wetlands and areas with low fertility have a positive influence for the presence and maintenance of primary vegetation. The analysis of these processes is very important for better understanding the regional dynamics of land use, and provide supporting information for a more efficient and sustainable regional planning.

Diversos estudos apontam uma forte influência do ambiente terrestre sobre os corpos dágua nele inseridos. No caso de riachos de cabeceira esta relação não se resume a variáveis químicas e físicas, mas também está ligada diretamente ao que chamamos de metabolismo do riacho, regulando o aporte direto de nutrientes em forma de folhiço e material particulado e a produtividade interna, através de incidência de luz. Estes são fatores que estão intrinsecamente ligados a manutenção deste metabolismo e por conseqüência da biodiversidade que existe nestes riachos. Este estudo, através da técnica isotópica do \'dela\'13C e \'delta\'15N e índices ecológicos (riqueza, abundância, diversidade, EPT e EPTC) comparou riachos de Mata Atlântica inseridos em ambientes com diferentes características. Primeiramente com relação à altitude, foram comparados riachos inseridos em matriz de Floresta Ombrófila Densa de Terras Baixas (5 a 50 m), sopé da Serra do Mar e de Floresta Ombrófila Densa Montana (500 a 1.200 m), topo da serra. E em um segundo momento, riachos em diferentes usos do solo, inseridos em matriz de floresta, eucalipto e pastagem. Foram encontradas diferenças não só relacionadas aos índices ecológicos, mas principalmente com relação as variáveis isotópicas, que apontaram mudanças nos padrões alimentares. Os riachos de terras baixas apresentaram um alto consumo de perifiton que foi substituído pelo consumo de material particulado nos riachos de altitude. O consumo de folhiço foi importante em ambas as altitudes e se manteve estável temporalmente. No caso de uso do solo, os riachos inseridos em plantações de eucalipto, seguiram um padrão muito próximo aos riachos florestados. Os padrões encontrados nos riachos de pastagem diferiram de ambas as fisionomias florestais apresentando um baixo consumo de folhiço e influência de plantas C4 na dieta de alguns invertebrados, além de uma grande variação interna explicada pela composição do folhiço e material particulado encontrados nestes riachos. / Several studies show a strong influence of terrestrial environment on streams contained therein. On headwater streams that influence is not just related to chemical and physical variables, but also is directly linked to what the stream metabolism, regulating the direct input of nutrients in the form of litter and particulate matter and internal productivity through light incidence. Factors that are inextricably linked to maintenance of these metabolism and consequently to the biodiversity that exists in these streams. This study, using the isotopic technique of \'delta\'13C and \'delta\'15N and ecological indexes (richness, abundance, diversity, EPT and EPTC) compared Atlantic Forest streams inserted in environments with different characteristics. We compared streams inserted in Tropical Rain Forest of lowlands (50-50 m), foothills of the Serra do Mar and Mountain Tropical Rain Forest (500-1200 m) upland. Also compared streams in different land uses, inserted into a matrix of forest, grassland and eucalyptus. Differences found on isotopic variables showed changes in dietary patterns. The lowland streams showed a high consumption of periphyton that was replaced by the consumption of particulate matter in the upland streams. Consumption of leaf litter was important in both altitudes and remained stable on both seasons. For land use comparison, streams inserted in eucalyptus plantations, followed a pattern similar to forested streams. The patterns found in pasture streams differed from both forest formations, showing a low consumption of leaf litter and influence of C4 plants in the diet of some invertebrates, as well as a large internal variation explained by the composition of litter and particulate matter collected in these streams.

<p>Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.</p>

<p>The Okavango river flows from southern Angola, through the Kavango region of Namibia and into the Okavango Delta in Botswana. The recent peace in Angola hopefully marks the end of the intense suffering that the peoples of the river basin have endured, and the beginning of sustainable decision-making in the area. Informed decision-making however requires knowledge; and there is a need for, and a lack of knowledge regarding basin-wide land cover (LC) changes, and their causes, during the Angolan civil war in the basin. Furthermore, there is a need for, and a lack of knowledge on how expanding large-scale agriculture and urban growth along the Angola-Namibia border affects the water quality of the river.</p><p>The aim of this study was therefore to develop a remote sensing method applicable to the basin (with scant ground-truth data availability) to carry out a systematic historic study of LC changes during the Angolan civil war, to apply the method to the basin, to relate these changes to major societal trends in the region, and to analyse potential impacts of expanding large-scale agriculture and urban growth on the water quality of the river along the Angola-Namibia border.</p><p>A range of remote sensing methods to study historic LC changes in the basin were tried and evaluated against reference data collected during a field visit in Namibia in October 2005. Eventually, two methods were selected and applied to pre-processed Landsat MSS and ETM+ satellite image mosaics of 1973 and 2001 respectively: 1. a combined unsupervised classification and pattern-recognition change detection method providing quantified and geographically distributed binary LC class change trajectory information and, 2. an NDVI (Normalised Difference Vegetation Index) change detection method providing quantified and geographically distributed continuous information on degrees of change in vegetation vigour. In addition, available documents and people initiated in the basin conditions were consulted in the pursuit of discerning major societal trends that the basin had undergone during the Angolan civil war. Finally, concentrations of nutrients (total phosphorous & total nitrogen), bacteria (faecal coliforms & faecal streptococci), conductivity, total dissolved solids, dissolved oxygen, pH, temperature and Secchi depth were sampled at 11 locations upstream and downstream of large-scale agricultural facilities and an urban area during the aforementioned field visit.</p><p>The nature, extent and geographical distribution of LC changes in the study area during the Angolan civil war were determined. The study area (150 922 km²) was the Angolan and Namibian parts of the basin. The results indicate that the vegetation vigour is dynamic and has decreased overall in the area, perhaps connected with precipitation differences between the years. However while the vigour decreased in the northwest, it increased in the northeast, and on more local scales the pattern was often more complex. With respect to migration out of Angola into Namibia, the LC changes followed expectations of more intense use in Namibia close to the border (0-5 km), but not at some distance (10-20 km), particularly east of Rundu. With respect to urbanisation, expectations of increased human impact locally were observed in e.g. Rundu, Menongue and Cuito Cuanavale. Road deterioration was also observed with Angolan urbanisation but some infrastructures appeared less damaged by the war. Some villages (e.g. Savitangaiala de Môma) seem to have been abandoned during the war so that the vegetation could regenerate, which was expected. But other villages (e.g. Techipeio) have not undergone the same vegetation regeneration suggesting they were not abandoned. The areal extent of large-scale agriculture increased 59% (26 km²) during the war, perhaps as a consequence of population growth. But the expansion was not nearly at par with the population growth of the Kavango region (320%), suggesting that a smaller proportion of the population relied on the large-scale agriculture for their subsistence in 2001 compared with 1973.</p><p>No significant impacts were found from the large-scale agriculture and urbanisation on the water quality during the dry season of 2005. Total phosphorous concentrations (with range: 0.067-0.095 mg l^-1) did vary significantly between locations (p=0.013) but locations upstream and downstream of large-scale agricultural facilities were not significantly different (p=0.5444). Neither did faecal coliforms (range: 23-63 counts per 100ml) nor faecal streptococci (range: 8-33 counts per 100ml) vary significantly between locations (p=0.332 and p=0.354 respectively). Thus the impact of Rundu and the extensive livestock farming along the border were not significant at this time. The Cuito river on the other hand significantly decreased both the conductivity (range: 27.2-49.7 μS cm^-1, p<0.0001) and the total dissolved solid concentration (range: 12.7-23.4 mg l^-1, p<0.0001) of the mainstream of the Okavango during the dry season.</p><p>Land cover changes during the Angolan civil war, contributing causes and effects on water quality were studied in this research effort. Many of the obtained results can be used directly or with further application as a knowledge base for sustainable decision-making and management in the basin. Wisely used by institutions charged with that objective, the information can contribute to sustainable development and the ending of suffering and poverty for the benefit of the peoples of the Okavango and beyond.</p>

Urban land cover mapping represents one of the most important remote sensing applications in the context of rapid global urbanization. In recent years, high resolution spaceborne Polarimetric Synthetic Aperture Radar (PolSAR) has been increasingly used for urban land cover/land-use mapping, since more information could be obtained in multiple polarizations and the collection of such data is less influenced by solar illumination and weather conditions.  The overall objective of this research is to develop effective methods to extract accurate and detailed urban land cover information from spaceborne PolSAR data. Six RADARSAT-2 fine-beam polarimetric SAR and three RADARSAT-2 ultra-fine beam SAR images were used. These data were acquired from June to September 2008 over the north urban-rural fringe of the Greater Toronto Area, Canada. The major landuse/land-cover classes in this area include high-density residential areas, low-density residential areas, industrial and commercial areas, construction sites, roads, streets, parks, golf courses, forests, pasture, water and two types of agricultural crops. In this research, various polarimetric SAR parameters were evaluated for urban land cover mapping. They include the parameters from Pauli, Freeman and Cloude-Pottier decompositions, coherency matrix, intensities of each polarization and their logarithms.  Both object-based and pixel-based classification approaches were investigated. Through an object-based Support Vector Machine (SVM) and a rule-based approach, efficiencies of various PolSAR features and the multitemporal data combinations were evaluated. For the pixel-based approach, a contextual Stochastic Expectation-Maximization (SEM) algorithm was proposed. With an adaptive Markov Random Field (MRF) and a modified Multiscale Pappas Adaptive Clustering (MPAC), contextual information was explored to improve the mapping results. To take full advantages of alternative PolSAR distribution models, a rule-based model selection approach was put forward in comparison with a dictionary-based approach.  Moreover, the capability of multitemporal fine-beam PolSAR data was compared with multitemporal ultra-fine beam C-HH SAR data. Texture analysis and a rule-based approach which explores the object features and the spatial relationships were applied for further improvement. Using the proposed approaches, detailed urban land-cover classes and finer urban structures could be mapped with high accuracy in contrast to most of the previous studies which have only focused on the extraction of urban extent or the mapping of very few urban classes. It is also one of the first comparisons of various PolSAR parameters for detailed urban mapping using an object-based approach. Unlike other multitemporal studies, the significance of complementary information from both ascending and descending SAR data and the temporal relationships in the data were the focus in the multitemporal analysis. Further, the proposed novel contextual analyses could effectively improve the pixel-based classification accuracy and present homogenous results with preserved shape details avoiding over-averaging. The proposed contextual SEM algorithm, which is one of the first to combine the adaptive MRF and the modified MPAC, was able to mitigate the degenerative problem in the traditional EM algorithms with fast convergence speed when dealing with many classes. This contextual SEM outperformed the contextual SVM in certain situations with regard to both accuracy and computation time. By using such a contextual algorithm, the common PolSAR data distribution models namely Wishart, G0p, Kp and KummerU were compared for detailed urban mapping in terms of both mapping accuracy and time efficiency. In the comparisons, G0p, Kp and KummerU demonstrated better performances with higher overall accuracies than Wishart. Nevertheless, the advantages of Wishart and the other models could also be effectively integrated by the proposed rule-based adaptive model selection, while limited improvement could be observed by the dictionary-based selection, which has been applied in previous studies. The use of polarimetric SAR data for identifying various urban classes was then compared with the ultra-fine-beam C-HH SAR data. The grey level co-occurrence matrix textures generated from the ultra-fine-beam C-HH SAR data were found to be more efficient than the corresponding PolSAR textures for identifying urban areas from rural areas. An object-based and pixel-based fusion approach that uses ultra-fine-beam C-HH SAR texture data with PolSAR data was developed. In contrast to many other fusion approaches that have explored pixel-based classification results to improve object-based classifications, the proposed rule-based fusion approach using the object features and contextual information was able to extract several low backscatter classes such as roads, streets and parks with reasonable accuracy. / <p>QC 20121112</p>

Relevant information is essential for finding solutions in Integrated Water Management (IWM). Complex water systems and a need for increasing integration of sectors, actors and scales in IWM require new methods for developing and managing such information. This thesis investigates the role of information within the IWM process, as well as the main challenges for development of representative, accessibleand harmonized information. Results show how information needs and the information production process for IWM may be systematized, and indicate a large potential for information system development for IWM. However, in order to reach the full potential, today’s limited and heterogeneous water information needs to become more comprehensive, transparent, interoperable, dynamic, scalable and openly accessible. Large pressures on water systems are found in coastal catchment areas that are unmonitored across the local to the global scale, indicating a large importance of these areas for nutrient and pollutant loading. The globally accessible runoff data from catchment areas that are rich in pressures from population, agriculture and general economic activity further exhibit a rapidly declining trend during recent years. Major water system changes may therefore pass unnoticed if analyzed on the basis of openly accessible runoff global data. Furthermore, large discrepancies are found between land cover databases, which may result in major uncertainties in quantification of water and evapotranspiration flows. Identified information challenges may be relatively easily overcome by making better use of available information, while other challenges such as development of consistent baselines of core data and a possible re-prioritization of water-environmental monitoring programs may be both difficult and costly.

The Earth's climate is changing and cities are facing a warmer future. As the locus of economic activity and concentrated populations on the planet, cities are both a primary driver of greenhouse gas emissions and places where the human health impacts of climate change are directly felt. Cities increase local temperatures through the conversion of natural land covers to urban uses, and exposures to elevated temperatures represent a serious and growing health threat for urban residents. This work is concerned with understanding the interactions of global trends in climate with local influences tied to urban land covers. First, it examines temperatures during an extended period of extreme heat and asks whether changes in land surface temperatures during a heat wave are consistent in space and time across all land cover types. Second, the influences of land covers on temperatures are considered for normal and extreme summer weather to find out which characteristics of the built environment most influence temperatures during periods of extreme heat. Finally, the distribution of health vulnerabilities related to extreme heat in cities are described and examined for spatial patterns. These topics are investigated using meteorology from the summer of 2006 to identify extremely hot days in the cities of Atlanta, Chicago, Philadelphia, and Phoenix and their surrounding metropolitan regions. Remotely sensed temperature data were examined with physical and social characteristics of the urban environment to answer the questions posed above. The findings confirm that urban land covers consistently exhibit higher temperatures than surrounding rural areas and are much more likely to be among the hottest in the region, during a heat wave specifically. In some cities urban thermal anomalies grew between the beginning and end of a heat wave. The importance of previously recognized built environment thermal influences (impervious cover and tree canopy) were present, and in some cases, emphasized during extreme summer weather. Extreme heat health health vulnerability related to environmental factors coincided spatially with risks related to social status. This finding suggests that populations with fewer resources for coping with extreme heat tend to reside in built environments that increase temperatures, and thus they may be experiencing increased thermal exposures. Physical interventions and policies related to the built environment can help to reduce urban temperatures, especially during periods of extremely hot weather which are predicted to become more frequent with global climate change. In portions of the city where populations with limited adaptive capacity are concentrated, modification of the urban landscape to decrease near surface longwave radiation can reduce the chances of adverse health effects related to extreme heat. The specific programs, policies, and design strategies pursued by cities and regions must be tailored with respect to scale, location, and cultural context. This work concludes with suggestions for such strategies.

The Okavango river flows from southern Angola, through the Kavango region of Namibia and into the Okavango Delta in Botswana. The recent peace in Angola hopefully marks the end of the intense suffering that the peoples of the river basin have endured, and the beginning of sustainable decision-making in the area. Informed decision-making however requires knowledge; and there is a need for, and a lack of knowledge regarding basin-wide land cover (LC) changes, and their causes, during the Angolan civil war in the basin. Furthermore, there is a need for, and a lack of knowledge on how expanding large-scale agriculture and urban growth along the Angola-Namibia border affects the water quality of the river. The aim of this study was therefore to develop a remote sensing method applicable to the basin (with scant ground-truth data availability) to carry out a systematic historic study of LC changes during the Angolan civil war, to apply the method to the basin, to relate these changes to major societal trends in the region, and to analyse potential impacts of expanding large-scale agriculture and urban growth on the water quality of the river along the Angola-Namibia border. A range of remote sensing methods to study historic LC changes in the basin were tried and evaluated against reference data collected during a field visit in Namibia in October 2005. Eventually, two methods were selected and applied to pre-processed Landsat MSS and ETM+ satellite image mosaics of 1973 and 2001 respectively: 1. a combined unsupervised classification and pattern-recognition change detection method providing quantified and geographically distributed binary LC class change trajectory information and, 2. an NDVI (Normalised Difference Vegetation Index) change detection method providing quantified and geographically distributed continuous information on degrees of change in vegetation vigour. In addition, available documents and people initiated in the basin conditions were consulted in the pursuit of discerning major societal trends that the basin had undergone during the Angolan civil war. Finally, concentrations of nutrients (total phosphorous &amp; total nitrogen), bacteria (faecal coliforms &amp; faecal streptococci), conductivity, total dissolved solids, dissolved oxygen, pH, temperature and Secchi depth were sampled at 11 locations upstream and downstream of large-scale agricultural facilities and an urban area during the aforementioned field visit. The nature, extent and geographical distribution of LC changes in the study area during the Angolan civil war were determined. The study area (150 922 km2) was the Angolan and Namibian parts of the basin. The results indicate that the vegetation vigour is dynamic and has decreased overall in the area, perhaps connected with precipitation differences between the years. However while the vigour decreased in the northwest, it increased in the northeast, and on more local scales the pattern was often more complex. With respect to migration out of Angola into Namibia, the LC changes followed expectations of more intense use in Namibia close to the border (0-5 km), but not at some distance (10-20 km), particularly east of Rundu. With respect to urbanisation, expectations of increased human impact locally were observed in e.g. Rundu, Menongue and Cuito Cuanavale. Road deterioration was also observed with Angolan urbanisation but some infrastructures appeared less damaged by the war. Some villages (e.g. Savitangaiala de Môma) seem to have been abandoned during the war so that the vegetation could regenerate, which was expected. But other villages (e.g. Techipeio) have not undergone the same vegetation regeneration suggesting they were not abandoned. The areal extent of large-scale agriculture increased 59% (26 km2) during the war, perhaps as a consequence of population growth. But the expansion was not nearly at par with the population growth of the Kavango region (320%), suggesting that a smaller proportion of the population relied on the large-scale agriculture for their subsistence in 2001 compared with 1973. No significant impacts were found from the large-scale agriculture and urbanisation on the water quality during the dry season of 2005. Total phosphorous concentrations (with range: 0.067-0.095 mg l-1) did vary significantly between locations (p=0.013) but locations upstream and downstream of large-scale agricultural facilities were not significantly different (p=0.5444). Neither did faecal coliforms (range: 23-63 counts per 100ml) nor faecal streptococci (range: 8-33 counts per 100ml) vary significantly between locations (p=0.332 and p=0.354 respectively). Thus the impact of Rundu and the extensive livestock farming along the border were not significant at this time. The Cuito river on the other hand significantly decreased both the conductivity (range: 27.2-49.7 μS cm-1, p&lt;0.0001) and the total dissolved solid concentration (range: 12.7-23.4 mg l-1, p&lt;0.0001) of the mainstream of the Okavango during the dry season. Land cover changes during the Angolan civil war, contributing causes and effects on water quality were studied in this research effort. Many of the obtained results can be used directly or with further application as a knowledge base for sustainable decision-making and management in the basin. Wisely used by institutions charged with that objective, the information can contribute to sustainable development and the ending of suffering and poverty for the benefit of the peoples of the Okavango and beyond.