Examination of bird assemblages along an environmental gradient which encompasses both climate and habitat change is needed if we are to better understand the potential effects of these changes for avians and the ecological process that depend upon them. Climate change is predicted to have a significant impact on deserts and desert margins, resulting in distributional shifts of entire ecosystems and new community associations. This study explores the probable responses of avian communities to increasing desertification. In general, species richness and numbers of birds in arid zones are low compared to more mesic areas. Different combinations of habitat types and the variety of patches in a landscape influence the diversity and community structures of avians in that landscape. The role of vegetation structure in avian habitat selection in semi-arid areas is dictated by horizontal habitat density as well as vertical structure. Although bird distribution is determined by habitat boundaries, most birds are flexible and can disperse across small habitat barriers. The hypothesis tested, was that bird species assemblages along an aridity gradient are affected primarily by rainfall and secondarily by habitat type. Assessing the impacts of rainfall and habitat on bird variables, such as species richness, abundance, diversity, biomass, and life history traits, were the objectives of the study. An east-west aridity gradient of 300 mm, stretching over 370 km, was chosen in central Namibia for the study area. The climate is harsh with localised rain and considerable daily fluctuations in temperature. Grasses, and trees and shrubs up to 7 m in height are the co-dominant life-forms. Surveys were conducted over three years; one winter and one summer survey in each year. Rainfall, seasons and vegetation height were recorded as environmental variables. Three structurally different habitat types were selected for stratified sampling: open areas, rivers and thickets. Open areas were dominated by grass; river refers to ephemeral dry river lines with mature trees; and thickets comprise woody shrubs and trees. At each site, the same three habitats were used for bird sampling, resulting in 15 sample units. Sampling took place on 51 discontinuous line transects of 1km in length and without a width limit. Univariate analyses included ANOVA and t-tests. Multivariate analyses consisted of cluster analysis, MRPP tests, indicator analysis, Shannon diversity index and NMS ordinations. NMS bi-plots were used to define avian community structures responding to aridity, habitat, migration and life history traits. The results showed that bird species richness, abundance, and diversity remained relatively constant across the aridity gradient, until they declined significantly once a certain aridity threshold was crossed at the most arid site. There were significantly more bird species and individual birds at the wetter sites than at the drier sites. Rivers contained more birds than thickened or open habitat types, suggesting the importance of riparian habitat types for maintaining avian diversity. The three more mesic sites included higher numbers of species from the nesting and feeding guilds, regardless of habitat type, than the two more arid sites. The aridity threshold had a significant effect on bird community structures: more migrant and nomadic species, and omnivore and insectivore species persisted in very arid conditions. From the results it was predicted that climate change will cause avian species to undergo range shifts from west to east, resulting in community composition changes and a reduction in diversity. Life history traits affect the adaptive capabilities of bird species and it is predicted that nomadism, flexibility in diet, and adaptability of nesting requirements will contribute to species persistence in the drier conditions predicted under current climate change scenarios. Dry river lines will act as refugia for avian diversity, but crucial habitat types that currently contain less diversity are also important for maintaining unique avian assemblages. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Examination of bird assemblages along an environmental gradient which encompasses both climate and habitat change is needed if we are to better understand the potential effects of these changes for avians and the ecological process that depend upon them. Climate change is predicted to have a significant impact on deserts and desert margins, resulting in distributional shifts of entire ecosystems and new community associations. This study explores the probable responses of avian communities to increasing desertification. In general, species richness and numbers of birds in arid zones are low compared to more mesic areas. Different combinations of habitat types and the variety of patches in a landscape influence the diversity and community structures of avians in that landscape. The role of vegetation structure in avian habitat selection in semi-arid areas is dictated by horizontal habitat density as well as vertical structure. Although bird distribution is determined by habitat boundaries, most birds are flexible and can disperse across small habitat barriers. The hypothesis tested, was that bird species assemblages along an aridity gradient are affected primarily by rainfall and secondarily by habitat type. Assessing the impacts of rainfall and habitat on bird variables, such as species richness, abundance, diversity, biomass, and life history traits, were the objectives of the study. An east-west aridity gradient of 300 mm, stretching over 370 km, was chosen in central Namibia for the study area. The climate is harsh with localised rain and considerable daily fluctuations in temperature. Grasses, and trees and shrubs up to 7 m in height are the co-dominant life-forms. Surveys were conducted over three years; one winter and one summer survey in each year. Rainfall, seasons and vegetation height were recorded as environmental variables. Three structurally different habitat types were selected for stratified sampling: open areas, rivers and thickets. Open areas were dominated by grass; river refers to ephemeral dry river lines with mature trees; and thickets comprise woody shrubs and trees. At each site, the same three habitats were used for bird sampling, resulting in 15 sample units. Sampling took place on 51 discontinuous line transects of 1km in length and without a width limit. Univariate analyses included ANOVA and t-tests. Multivariate analyses consisted of cluster analysis, MRPP tests, indicator analysis, Shannon diversity index and NMS ordinations. NMS bi-plots were used to define avian community structures responding to aridity, habitat, migration and life history traits. The results showed that bird species richness, abundance, and diversity remained relatively constant across the aridity gradient, until they declined significantly once a certain aridity threshold was crossed at the most arid site. There were significantly more bird species and individual birds at the wetter sites than at the drier sites. Rivers contained more birds than thickened or open habitat types, suggesting the importance of riparian habitat types for maintaining avian diversity. The three more mesic sites included higher numbers of species from the nesting and feeding guilds, regardless of habitat type, than the two more arid sites. The aridity threshold had a significant effect on bird community structures: more migrant and nomadic species, and omnivore and insectivore species persisted in very arid conditions. From the results it was predicted that climate change will cause avian species to undergo range shifts from west to east, resulting in community composition changes and a reduction in diversity. Life history traits affect the adaptive capabilities of bird species and it is predicted that nomadism, flexibility in diet, and adaptability of nesting requirements will contribute to species persistence in the drier conditions predicted under current climate change scenarios. Dry river lines will act as refugia for avian diversity, but crucial habitat types that currently contain less diversity are also important for maintaining unique avian assemblages. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Consideramos a região costeira e oceânica abrangida neste estudo como um sistema de grande escala, que se extende dês Cabo Frio(RJ) (lat. 23º00S) até Cananéia(SP) (lat. 25º00S) Nas análises de uma série temporal dos dados de temperatura da superfície do mar obtido por sensoriamento remoto pelo satélite NOAA/4 foram observadas diferenças no tempo de ocorrência das máximas e mínimas temperatura médias mensais em relação à estação costeira de Cananéia(SP). Essa diferença foi de dois meses para o máximo e um mês para o mínimo. Para o componente anual de variação de temperatura observamos áreas de maiores amplitudes de temperatura da superfície do mar (Cabo Frio-RJ. Influência do fenômeno de ressurgência e Cananéia-SP, influência da corrente das Malvinas) e de menores amplitudes nas áreas costeira e oceânica (entre Ubatuba-SP e Santos_SP, indicando uma área termicamente mais estável)> Para os componentes com período de 06, 04 e 03 meses as maiores amplitudes ocorrem nas mesmas áreas já citadas, com exceção da região oceânica (lat. 25º30S e long. 042º00W) para o componente de 06 meses. A circulação na região adjacentes à Ilha Grande-RJ (lat. 23º15S), cuja amostragem foi realizada em escala média, foi descrita através de diagramas vetoriais progressivos (determinamos um circulação de fundo do sentido horário na Baía de Ilha Grande-RJ, em junhop de 1976). As flutuações de curto período foram determinadas através da análise de - autocorrelação obtendo-se os seguintes resultados: na parte oeste da baía, flutuações de ordem de 35 a 70 min; na parte leste da baía, flutuações da ordem de 50 a 70 min e flutuações da ordem de 3h 30min e 5h e 24min, para as profundidades - médias e próximos ao fundo, respectivamente. O caráter turbulento dos movimentos observados foi determinado através do Número de Richardson. As propriedades dispersivas nessa região foram simuladas experimentalmente, sendo os coeficientes de difusão (k - 3.5 x 10³ e 9.0 x 10³ cm².s -¹ ) determinados por técnica. fluorométricas com o uso da Rhodamina-B como traçador. / The oceanic and coastal área from Cabo Frio (RJ) (23º00S lat.) Cananéia (SP) (25°00\'S lat.) was considered large scale systems. Through time series analysis of the NOAA-4 sea surface temperature (SST) data, time differences in the occurrence of maximum and minimun mean monthly SST were observed and showed the maximum surface Walter temperature to lag coastal land station (Cananéia)by 2 months and the minimum by 1 months. For annual component of SST maximum amplirtudes were observed at Cabo Frio (upwelling Influences) and Cananéia (Malvinas Current Influences) and minimum amplitudes at coastal and oceanic area between Ubatuba(SP) and Santos (SP)(more thermal stable area). For the 6. 4 and Santos 3 month components the maximum amplitudes occurred at the areas mentioned previously, with exception to the oceanic area(25º30\'S lat. And 042º00w long.) for 6 month component. A mesoscale study was also made pn the Ilha Grande(RJ) area(23º15S lat.). The circulation was described through progressive vector diagrams (PVDs) (clockwise bottom circulatin was determined in June. 1976). Evaluation of the short period fluctuation was determined through autocorrelation analysis: West part of bay (35 to 70 min). East part of bay (50 to 70 min mean depth and 3h30 min to 5h24 min bottom depth. Studies of turbulence were made through the use of the Richardson Number. Two disperation (e.g. k + 3,5 x 10³ cm² sec-¹ and 9 x 10³ cm² sec-¹) studies were Rhodamine B exporiments.

A riparian ecosystem is the area between the aquatic and terrestrial setting of a stream, and serves as a corridor and habitat for birds. Several riparian ecosystems are located in urban environments, and three main riparian corridors are located in Potchefstroom. They are the Mooi River, Wasgoed Spruit, and Spitskop Spruit, which encompass a wide range of different vegetation types and anthropogenic factors. Therefore, different habitat types for birds occur along the riparian corridors of Potchefstroom. Factors such as food and water availability, nesting sites, competition, predation, learning, presence of other species, and those species that are able to adapt to environmental changes influence the avian diversity and communities along riparian corridors. The hypothesis is that bird variables along the riparian corridors in Potchefstroom are affected by vegetation, anthropogenic, and seasonal influences. To investigate these affects, two secondary objectives were formulated. The first was to characterise riparian avian habitats (CAHs) according to vegetation and anthropogenic factors, and the second was to identify temporal and spatial changes in avian variables. The three streams were divided into 79 consecutive transects, each 300 m long. The study area consisted of: 17 transects along Spitskop Spruit, 12 along Wasgoed Spruit and 50 along the Mooi River. Bird observations were conducted monthly from June 2006 to June 2007. Birds that were observed with a perpendicular distance ≤ 30 meters towards the streams were included in the results. The bird species that were observed were also classified into different nesting and feeding guilds. Environmental data recorded included: vegetation structure (estimated cover percentages and height classes of trees, shrubs, grasses, herbs, sedges, and reeds), anthropogenic structures (estimated cover percentages of roads, footpaths, bridges, electrical pylons, houses, and drainage pipes), and the presence of informal settlers along each transect (the mean number of people and the space they occupy). Vegetation was monitored in summer– (February 2007 until April 2007) and winter months (June 2007 until August 2007). The anthropogenic structures and the presence of informal settlers (anthropogenic factors) were monitored simultaneously with the bird counts. Transect-time profiles were drawn for the four parameters, which differed on spatial and time scales. Multivariate analyses included non-metric multidimensional scaling (NMS), cluster analysis, and indicator species analysis. Cluster analyses and NMS bi-plots were used to define characterised avian habitats (CAHs). Two types of CAHs were characterised: Summer CAHs (summer vegetation and anthropogenic factors) and Anthropogenically CAHs (Anthropogenic factors alone). Bird species were then ordinated with the summer and anthropogenically CAHs on NMS successional vector graphs. The successional vectors illustrate the avian community trajectories of the different CAHs. Indicator species analyses were performed to describe associations between the bird species and the summer and anthropogenically CAHs. The summer and anthropogenic CAHs that were characterised had different avian community trajectories and different species were associated with these CAHs. Different levels in avian diversity appeared among these CAHs, and convergence and divergence in communities appeared among these CAHs. Birds also selected their habitats according to feeding and nesting behaviours. Consequently, it can be deduced that environmental factors such as vegetation structures and anthropogenic factors, as well as seasonality, had an effect on the distribution of birds along the riparian corridors of Potchefstroom. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013

A riparian ecosystem is the area between the aquatic and terrestrial setting of a stream, and serves as a corridor and habitat for birds. Several riparian ecosystems are located in urban environments, and three main riparian corridors are located in Potchefstroom. They are the Mooi River, Wasgoed Spruit, and Spitskop Spruit, which encompass a wide range of different vegetation types and anthropogenic factors. Therefore, different habitat types for birds occur along the riparian corridors of Potchefstroom. Factors such as food and water availability, nesting sites, competition, predation, learning, presence of other species, and those species that are able to adapt to environmental changes influence the avian diversity and communities along riparian corridors. The hypothesis is that bird variables along the riparian corridors in Potchefstroom are affected by vegetation, anthropogenic, and seasonal influences. To investigate these affects, two secondary objectives were formulated. The first was to characterise riparian avian habitats (CAHs) according to vegetation and anthropogenic factors, and the second was to identify temporal and spatial changes in avian variables. The three streams were divided into 79 consecutive transects, each 300 m long. The study area consisted of: 17 transects along Spitskop Spruit, 12 along Wasgoed Spruit and 50 along the Mooi River. Bird observations were conducted monthly from June 2006 to June 2007. Birds that were observed with a perpendicular distance ≤ 30 meters towards the streams were included in the results. The bird species that were observed were also classified into different nesting and feeding guilds. Environmental data recorded included: vegetation structure (estimated cover percentages and height classes of trees, shrubs, grasses, herbs, sedges, and reeds), anthropogenic structures (estimated cover percentages of roads, footpaths, bridges, electrical pylons, houses, and drainage pipes), and the presence of informal settlers along each transect (the mean number of people and the space they occupy). Vegetation was monitored in summer– (February 2007 until April 2007) and winter months (June 2007 until August 2007). The anthropogenic structures and the presence of informal settlers (anthropogenic factors) were monitored simultaneously with the bird counts. Transect-time profiles were drawn for the four parameters, which differed on spatial and time scales. Multivariate analyses included non-metric multidimensional scaling (NMS), cluster analysis, and indicator species analysis. Cluster analyses and NMS bi-plots were used to define characterised avian habitats (CAHs). Two types of CAHs were characterised: Summer CAHs (summer vegetation and anthropogenic factors) and Anthropogenically CAHs (Anthropogenic factors alone). Bird species were then ordinated with the summer and anthropogenically CAHs on NMS successional vector graphs. The successional vectors illustrate the avian community trajectories of the different CAHs. Indicator species analyses were performed to describe associations between the bird species and the summer and anthropogenically CAHs. The summer and anthropogenic CAHs that were characterised had different avian community trajectories and different species were associated with these CAHs. Different levels in avian diversity appeared among these CAHs, and convergence and divergence in communities appeared among these CAHs. Birds also selected their habitats according to feeding and nesting behaviours. Consequently, it can be deduced that environmental factors such as vegetation structures and anthropogenic factors, as well as seasonality, had an effect on the distribution of birds along the riparian corridors of Potchefstroom. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013

Consideramos a região costeira e oceânica abrangida neste estudo como um sistema de grande escala, que se extende dês Cabo Frio(RJ) (lat. 23º00S) até Cananéia(SP) (lat. 25º00S) Nas análises de uma série temporal dos dados de temperatura da superfície do mar obtido por sensoriamento remoto pelo satélite NOAA/4 foram observadas diferenças no tempo de ocorrência das máximas e mínimas temperatura médias mensais em relação à estação costeira de Cananéia(SP). Essa diferença foi de dois meses para o máximo e um mês para o mínimo. Para o componente anual de variação de temperatura observamos áreas de maiores amplitudes de temperatura da superfície do mar (Cabo Frio-RJ. Influência do fenômeno de ressurgência e Cananéia-SP, influência da corrente das Malvinas) e de menores amplitudes nas áreas costeira e oceânica (entre Ubatuba-SP e Santos_SP, indicando uma área termicamente mais estável)> Para os componentes com período de 06, 04 e 03 meses as maiores amplitudes ocorrem nas mesmas áreas já citadas, com exceção da região oceânica (lat. 25º30S e long. 042º00W) para o componente de 06 meses. A circulação na região adjacentes à Ilha Grande-RJ (lat. 23º15S), cuja amostragem foi realizada em escala média, foi descrita através de diagramas vetoriais progressivos (determinamos um circulação de fundo do sentido horário na Baía de Ilha Grande-RJ, em junhop de 1976). As flutuações de curto período foram determinadas através da análise de - autocorrelação obtendo-se os seguintes resultados: na parte oeste da baía, flutuações de ordem de 35 a 70 min; na parte leste da baía, flutuações da ordem de 50 a 70 min e flutuações da ordem de 3h 30min e 5h e 24min, para as profundidades - médias e próximos ao fundo, respectivamente. O caráter turbulento dos movimentos observados foi determinado através do Número de Richardson. As propriedades dispersivas nessa região foram simuladas experimentalmente, sendo os coeficientes de difusão (k - 3.5 x 10³ e 9.0 x 10³ cm².s -¹ ) determinados por técnica. fluorométricas com o uso da Rhodamina-B como traçador. / The oceanic and coastal área from Cabo Frio (RJ) (23º00S lat.) Cananéia (SP) (25°00\'S lat.) was considered large scale systems. Through time series analysis of the NOAA-4 sea surface temperature (SST) data, time differences in the occurrence of maximum and minimun mean monthly SST were observed and showed the maximum surface Walter temperature to lag coastal land station (Cananéia)by 2 months and the minimum by 1 months. For annual component of SST maximum amplirtudes were observed at Cabo Frio (upwelling Influences) and Cananéia (Malvinas Current Influences) and minimum amplitudes at coastal and oceanic area between Ubatuba(SP) and Santos (SP)(more thermal stable area). For the 6. 4 and Santos 3 month components the maximum amplitudes occurred at the areas mentioned previously, with exception to the oceanic area(25º30\'S lat. And 042º00w long.) for 6 month component. A mesoscale study was also made pn the Ilha Grande(RJ) area(23º15S lat.). The circulation was described through progressive vector diagrams (PVDs) (clockwise bottom circulatin was determined in June. 1976). Evaluation of the short period fluctuation was determined through autocorrelation analysis: West part of bay (35 to 70 min). East part of bay (50 to 70 min mean depth and 3h30 min to 5h24 min bottom depth. Studies of turbulence were made through the use of the Richardson Number. Two disperation (e.g. k + 3,5 x 10³ cm² sec-¹ and 9 x 10³ cm² sec-¹) studies were Rhodamine B exporiments.