As aves de rapina, como predadores de níveis superiores na rede trófica, necessitam de grandes áreas de vida e ocorrem em baixa densidade populacional. São sensíveis a alteração e degradação do habitat, sendo bons indicadores de qualidade de habitat e biodiversidade. Apesar da importância ecológica pouco se conhece sobre a biologia e ecologia da maioria das 91 espécies que ocorrem na América do Sul, o que nos leva ao objetivo mais amplo desta tese: descrever a composição das taxocenoses de aves de rapina dos campos do sul do Brasil e Uruguai e sua relação com as características topográficas e ambientais. Para tanto, foram realizadas amostragens de aves de rapina em 11 áreas campestres entre outono de 2009 e verão de 2011. Um total de 44 transectos rodoviários foi amostrado sazonalmente, duas vezes ao ano, totalizando 176 amostragens. Ao todo foram observadas 18.424 aves de rapina, pertencentes a 33 espécies. Os transectos rodoviários são amplamente utilizados para a amostragem de aves de rapina, no entanto, nossos resultados sugerem que este método pode subestimar a abundância das espécies. Pontos de contagem parecem ser mais eficazes, principalmente para a amostragem de espécies raras. A distribuição das espécies foi associada à altitude e disponibilidade de habitat, e quatro taxocenoses puderam ser identificadas no sudeste da América do Sul. A taxocenose dos campos de altitude (na ecorregião Floresta Úmida com Araucária) se caracterizou pela presença de espécies florestais, ausentes ou pouco abundantes nas demais áreas. Na ecorregião Savana Uruguaia foram distinguidas outras três taxocenoses: 1) campos da planície costeira do sul do Brasil, com espécies associadas às áreas úmidas e ambientes alterados; 2) campos da Serra do Sudeste, uma taxocenose mista com espécies campestres e florestais, porém pouco abundantes e com maior tolerância a habitat alterados; 3) campos da Savana Uruguaia, taxocenose com predominância de espécies campestres e presença pontual de espécies florestais associadas a matas riparias. Foram registradas quatro espécies de necrófagos obrigatórios (Cathartiformes). A organização da taxocenose dos necrófagos aparenta ser mais influenciada pelas características da paisagem que por relações hierárquicas interespecíficas, mas a distribuição atual pode ter sido influenciada pela caça e envenenamento das espécies, ocorrida no século passado. A abundância das aves de rapina variou sazonalmente. A abundância foi significativamente maior no verão que no inverno, mas variou conforme a espécie. Quatro espécies são migratórias (duas migrantes trans-equatorias e duas intratropicais), três são parcialmente migratórias, mas o padrão de migração e as rotas são pouco conhecidos, e três espécies são nômades ou realizam movimentos irruptivos. Os campos do sudeste da América do Sul tem uma alta diversidade de aves de rapina, influenciada pela topografia, disponibilidade de habitat e sazonalidade, características que devem ser consideradas nas políticas de conservação na região. / Raptors, as top predators, have large home ranges and low population densities. They are sensitive to human perturbation and habitat degradation; hence raptors are sentinel species and biodiversity indicators. Despite their ecological importance, the biology and ecology of most of the 91 South American raptors is poorly known. The main objectives of this study were to examine the assemblage composition in grasslands of southern Brazil and Uruguay and to investigate its relation with topography and habitat features. To achieve this, 44 roadside transects were conducted in 11 areas. Each transect was survey four times between autumn/2009 and summer/2011. The 176 transects yielded 18,424 contacts of raptors, belonging to 34 species. Roadside line transect is widely used to survey raptors. However, our results suggest that this method could underestimate the species abundance. Roadside point transect seems to be better, especially to survey rare species. Raptors distribution and assemblage composition were related to altitude and habitat availability, and four assemblages could be identified in southeastern South America. Raptor assemblage at Altitudinal grasslands (in the Araucarian Moist Forest ecoregion) had higher abundances of forest raptors than the other regions. Three assemblages were distinguished in the Uruguayan Savannas ecoregion: 1) south Brazilian coastal plain, with species related wetlands and human modified habitats; 2) Serra do Sudeste grasslands, a mix of forest and grassland raptors assemblage, which showed low abundances and lower sensibility to habitat degradation; 3) Uruguayan Savannas, dominated by grasslands species and few forest species usually found in riparian habitats. Four obligate scavengers (Cathartiformes) were recorded. Landscape features appeared to be more important to the assemblage organization than interspecific hierarchy, but the current distribution and abundance of scavengers could have been driven by species persecution and poisoning in the last century. Raptors abundance changed seasonally. Total abundance was significantly higher during summer than winter, and strategies to deal with seasonality varied between species. Four species are complete migrants (two transequatorial and two intratropical), three are partial migrants, but their routes and migration pattern remain poorly understood; and three species are irruptive or nomadic. The grasslands of southern South America have a high diversity of raptors, influenced by topography, habitat availability and seasonality, features that should be taken into account when divising regional conservation policies.

Protected area site selection is generally carried out using biodiversity data as surrogates. However, reliable and complete biodiversity data is rarely available due to limited resources, time and equipment. Instead of drawing on inadequate biodiversity data, an alternative is to use environmental diversity (ED) as a surrogate in conservation planning. However, there are few studies that use environmental diversity for site selection or that evaluates its efficiency / unfortunately, no such example exists for Turkey, where biodiversity is high but our knowledge about it is unsatisfactory. Hence, this study was carried out to investigate the efficiency of environmental surrogates and the utility of different biological taxa in conservation planning. The objective was to find out the most efficient surrogates, either environmental or biological, for conservation planning, so that limited resources can be used more efficiently to establish an effective protected areas network. The study was carried out in northeastern Turkey, within the Lesser Caucasus ecoregion. The taxonomic groups considered include large mammals, breeding birds, globally threatened reptiles and amphibians, butterflies, highly threatened plants, and ecological communities. The distribution data was taken from a previous study, while climate and topographical data were obtained from various sources and produced through spatio-statistical techniques. Complementarity-based site selection was carried out with Marxan software, where the planning unit was the 100 sq.km. UTM grid square. Various statistical methods, including geographically weighted regression, principal components analysis, and p-median algorithm, were used to determine ED across the units. Performance of different approaches and different sets of surrogates were tested by comparing them to a random null model as well as representation success. Results indicate that endemic or non-endemic highly threatened plant species, butterfly species and ecological communities represent biodiversity better than other taxa in the study area. As such, they can be used on their own as efficient biodiversity surrogates in conservation area planning. Another finding is that highly threatened plant species are required to be used in the site selection process if they need to be represented well / in other words, they are their own surrogates. It was demonstrated that while ED alone can be used as a surrogate to represent biodiversity of an area, they are not as good as biodiversity surrogates themselves. It is also suggested that using species taxa with smaller distributional ranges or taxa that complement each other due to ecological differences as surrogates provide better results. On the other hand, ED might be a more suitable surrogate if resources are very limited or field work is impossible. In such cases, using ED in conjunction with one of the better biodiversity surrogates is probably the best solution.

As aves de rapina, como predadores de níveis superiores na rede trófica, necessitam de grandes áreas de vida e ocorrem em baixa densidade populacional. São sensíveis a alteração e degradação do habitat, sendo bons indicadores de qualidade de habitat e biodiversidade. Apesar da importância ecológica pouco se conhece sobre a biologia e ecologia da maioria das 91 espécies que ocorrem na América do Sul, o que nos leva ao objetivo mais amplo desta tese: descrever a composição das taxocenoses de aves de rapina dos campos do sul do Brasil e Uruguai e sua relação com as características topográficas e ambientais. Para tanto, foram realizadas amostragens de aves de rapina em 11 áreas campestres entre outono de 2009 e verão de 2011. Um total de 44 transectos rodoviários foi amostrado sazonalmente, duas vezes ao ano, totalizando 176 amostragens. Ao todo foram observadas 18.424 aves de rapina, pertencentes a 33 espécies. Os transectos rodoviários são amplamente utilizados para a amostragem de aves de rapina, no entanto, nossos resultados sugerem que este método pode subestimar a abundância das espécies. Pontos de contagem parecem ser mais eficazes, principalmente para a amostragem de espécies raras. A distribuição das espécies foi associada à altitude e disponibilidade de habitat, e quatro taxocenoses puderam ser identificadas no sudeste da América do Sul. A taxocenose dos campos de altitude (na ecorregião Floresta Úmida com Araucária) se caracterizou pela presença de espécies florestais, ausentes ou pouco abundantes nas demais áreas. Na ecorregião Savana Uruguaia foram distinguidas outras três taxocenoses: 1) campos da planície costeira do sul do Brasil, com espécies associadas às áreas úmidas e ambientes alterados; 2) campos da Serra do Sudeste, uma taxocenose mista com espécies campestres e florestais, porém pouco abundantes e com maior tolerância a habitat alterados; 3) campos da Savana Uruguaia, taxocenose com predominância de espécies campestres e presença pontual de espécies florestais associadas a matas riparias. Foram registradas quatro espécies de necrófagos obrigatórios (Cathartiformes). A organização da taxocenose dos necrófagos aparenta ser mais influenciada pelas características da paisagem que por relações hierárquicas interespecíficas, mas a distribuição atual pode ter sido influenciada pela caça e envenenamento das espécies, ocorrida no século passado. A abundância das aves de rapina variou sazonalmente. A abundância foi significativamente maior no verão que no inverno, mas variou conforme a espécie. Quatro espécies são migratórias (duas migrantes trans-equatorias e duas intratropicais), três são parcialmente migratórias, mas o padrão de migração e as rotas são pouco conhecidos, e três espécies são nômades ou realizam movimentos irruptivos. Os campos do sudeste da América do Sul tem uma alta diversidade de aves de rapina, influenciada pela topografia, disponibilidade de habitat e sazonalidade, características que devem ser consideradas nas políticas de conservação na região. / Raptors, as top predators, have large home ranges and low population densities. They are sensitive to human perturbation and habitat degradation; hence raptors are sentinel species and biodiversity indicators. Despite their ecological importance, the biology and ecology of most of the 91 South American raptors is poorly known. The main objectives of this study were to examine the assemblage composition in grasslands of southern Brazil and Uruguay and to investigate its relation with topography and habitat features. To achieve this, 44 roadside transects were conducted in 11 areas. Each transect was survey four times between autumn/2009 and summer/2011. The 176 transects yielded 18,424 contacts of raptors, belonging to 34 species. Roadside line transect is widely used to survey raptors. However, our results suggest that this method could underestimate the species abundance. Roadside point transect seems to be better, especially to survey rare species. Raptors distribution and assemblage composition were related to altitude and habitat availability, and four assemblages could be identified in southeastern South America. Raptor assemblage at Altitudinal grasslands (in the Araucarian Moist Forest ecoregion) had higher abundances of forest raptors than the other regions. Three assemblages were distinguished in the Uruguayan Savannas ecoregion: 1) south Brazilian coastal plain, with species related wetlands and human modified habitats; 2) Serra do Sudeste grasslands, a mix of forest and grassland raptors assemblage, which showed low abundances and lower sensibility to habitat degradation; 3) Uruguayan Savannas, dominated by grasslands species and few forest species usually found in riparian habitats. Four obligate scavengers (Cathartiformes) were recorded. Landscape features appeared to be more important to the assemblage organization than interspecific hierarchy, but the current distribution and abundance of scavengers could have been driven by species persecution and poisoning in the last century. Raptors abundance changed seasonally. Total abundance was significantly higher during summer than winter, and strategies to deal with seasonality varied between species. Four species are complete migrants (two transequatorial and two intratropical), three are partial migrants, but their routes and migration pattern remain poorly understood; and three species are irruptive or nomadic. The grasslands of southern South America have a high diversity of raptors, influenced by topography, habitat availability and seasonality, features that should be taken into account when divising regional conservation policies.

Master of Regional and Community Planning / Department of Landscape Architecture/Regional and Community Planning / John W. Keller / The Great Plains possesses one of the best sources of wind energy in North America. Based upon the need to diversify energy production domestically, wind energy’s future in both the immediate and long term should be dynamic. The success of wide scale development of this potential will be largely determined by the perceptions of local residents, who are most affected by the siting and design of wind energy projects. Currently, regulation of this natural resource is left largely to state and county governments. A majority of these entities in the Great Plains region have no regulations governing wind energy development or employ a patchwork of "borrowed" codes from across the nation. The system of regulation of natural resources by political boundary is archaic. It fails to recognize that there are high degrees of correlation between social, economic, and natural resources without respect for artificial political boundaries. This study is the first in the Great Plains to examine public attitudes toward the development of wind energy and its relationship to the landscape based upon ecological regions rather than political boundaries. The analysis of collected data will provide a useful tool for local planners, policy makers, and the general public in understanding the prevalent issues involved with wind energy development in this region.

As aves de rapina, como predadores de níveis superiores na rede trófica, necessitam de grandes áreas de vida e ocorrem em baixa densidade populacional. São sensíveis a alteração e degradação do habitat, sendo bons indicadores de qualidade de habitat e biodiversidade. Apesar da importância ecológica pouco se conhece sobre a biologia e ecologia da maioria das 91 espécies que ocorrem na América do Sul, o que nos leva ao objetivo mais amplo desta tese: descrever a composição das taxocenoses de aves de rapina dos campos do sul do Brasil e Uruguai e sua relação com as características topográficas e ambientais. Para tanto, foram realizadas amostragens de aves de rapina em 11 áreas campestres entre outono de 2009 e verão de 2011. Um total de 44 transectos rodoviários foi amostrado sazonalmente, duas vezes ao ano, totalizando 176 amostragens. Ao todo foram observadas 18.424 aves de rapina, pertencentes a 33 espécies. Os transectos rodoviários são amplamente utilizados para a amostragem de aves de rapina, no entanto, nossos resultados sugerem que este método pode subestimar a abundância das espécies. Pontos de contagem parecem ser mais eficazes, principalmente para a amostragem de espécies raras. A distribuição das espécies foi associada à altitude e disponibilidade de habitat, e quatro taxocenoses puderam ser identificadas no sudeste da América do Sul. A taxocenose dos campos de altitude (na ecorregião Floresta Úmida com Araucária) se caracterizou pela presença de espécies florestais, ausentes ou pouco abundantes nas demais áreas. Na ecorregião Savana Uruguaia foram distinguidas outras três taxocenoses: 1) campos da planície costeira do sul do Brasil, com espécies associadas às áreas úmidas e ambientes alterados; 2) campos da Serra do Sudeste, uma taxocenose mista com espécies campestres e florestais, porém pouco abundantes e com maior tolerância a habitat alterados; 3) campos da Savana Uruguaia, taxocenose com predominância de espécies campestres e presença pontual de espécies florestais associadas a matas riparias. Foram registradas quatro espécies de necrófagos obrigatórios (Cathartiformes). A organização da taxocenose dos necrófagos aparenta ser mais influenciada pelas características da paisagem que por relações hierárquicas interespecíficas, mas a distribuição atual pode ter sido influenciada pela caça e envenenamento das espécies, ocorrida no século passado. A abundância das aves de rapina variou sazonalmente. A abundância foi significativamente maior no verão que no inverno, mas variou conforme a espécie. Quatro espécies são migratórias (duas migrantes trans-equatorias e duas intratropicais), três são parcialmente migratórias, mas o padrão de migração e as rotas são pouco conhecidos, e três espécies são nômades ou realizam movimentos irruptivos. Os campos do sudeste da América do Sul tem uma alta diversidade de aves de rapina, influenciada pela topografia, disponibilidade de habitat e sazonalidade, características que devem ser consideradas nas políticas de conservação na região. / Raptors, as top predators, have large home ranges and low population densities. They are sensitive to human perturbation and habitat degradation; hence raptors are sentinel species and biodiversity indicators. Despite their ecological importance, the biology and ecology of most of the 91 South American raptors is poorly known. The main objectives of this study were to examine the assemblage composition in grasslands of southern Brazil and Uruguay and to investigate its relation with topography and habitat features. To achieve this, 44 roadside transects were conducted in 11 areas. Each transect was survey four times between autumn/2009 and summer/2011. The 176 transects yielded 18,424 contacts of raptors, belonging to 34 species. Roadside line transect is widely used to survey raptors. However, our results suggest that this method could underestimate the species abundance. Roadside point transect seems to be better, especially to survey rare species. Raptors distribution and assemblage composition were related to altitude and habitat availability, and four assemblages could be identified in southeastern South America. Raptor assemblage at Altitudinal grasslands (in the Araucarian Moist Forest ecoregion) had higher abundances of forest raptors than the other regions. Three assemblages were distinguished in the Uruguayan Savannas ecoregion: 1) south Brazilian coastal plain, with species related wetlands and human modified habitats; 2) Serra do Sudeste grasslands, a mix of forest and grassland raptors assemblage, which showed low abundances and lower sensibility to habitat degradation; 3) Uruguayan Savannas, dominated by grasslands species and few forest species usually found in riparian habitats. Four obligate scavengers (Cathartiformes) were recorded. Landscape features appeared to be more important to the assemblage organization than interspecific hierarchy, but the current distribution and abundance of scavengers could have been driven by species persecution and poisoning in the last century. Raptors abundance changed seasonally. Total abundance was significantly higher during summer than winter, and strategies to deal with seasonality varied between species. Four species are complete migrants (two transequatorial and two intratropical), three are partial migrants, but their routes and migration pattern remain poorly understood; and three species are irruptive or nomadic. The grasslands of southern South America have a high diversity of raptors, influenced by topography, habitat availability and seasonality, features that should be taken into account when divising regional conservation policies.

No description available.

Made available in DSpace on 2014-12-17T14:02:01Z (GMT). No. of bitstreams: 1 WallaceSN_DISSERT.pdf: 4760466 bytes, checksum: 02e9f4b160af4472ebf0590033624755 (MD5) Previous issue date: 2010-06-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning / O bioma Caatinga ? rico em v?rias esp?cies end?micas da ictiofauna. O presente trabalho teve como objetivo verificar a diversidade da ictiofauna da bacia do Rio Piranhas-Assu, RN inserida no bioma Caatinga, alem de verificar os aspectos reprodutivos de uma esp?cie de peixe nativa, piau preto, Leporinus piau (Osteichthyes: Anostomidae). Foram realizadas amostragens mensais entre setembro de 2008 a dezembro de 2009. Foram capturados 602 peixes, distribu?dos em quatro ordens (Characiformes, Perciformes, Siluriformes e Synbranchiformes), 11 fam?lias (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae), e 22 esp?cies, sendo 17 end?micas, quatro introduzidas de outras bacias e uma ex?tica. A ordem Characiformes foi mais representativa em n?mero de esp?cies (46,35%) seguidas por Perciformes (35,38%), Siluriformes (17,44%) e Synbranchiformes (0,5%). A til?pia do Nilo, Oreochomis niloticus, a ?nica esp?cie ex?tica registrada foi mais expressiva em n?mero de indiv?duos (24,92%) seguida pela esp?cie nativa o piau-preto, Leporinus piau (18,77 %). Quando considerado a freq??ncia relativa de ocorr?ncia das 22 esp?cies, 13 foram constantes, cinco acess?rias e quatro raras. Medidas de gest?o ambiental devem ser tomadas para conserva??o das esp?cies end?micas da bacia do Rio Piranhas-Assu do bioma Caatinga. Para investigar os aspectos reprodutivos de peixe nativo piau preto, L. piau, foi capturado um total de 211 exemplares. Os par?metros ambientais, como pluviosidade, temperatura, pH, condutividade el?trica e oxig?nio dissolvido da ?gua foram registradas. A popula??o amostrada mostrou uma leve predomin?ncia de machos (55%) e as f?meas foram maiores em comprimento e mais pesadas. Ambos os sexos de L. piau apresentaram um crescimento alom?trico positivo, indicando um maior incremento de peso do que comprimento. A primeira matura??o sexual dos machos ocorreu mais em tamanho menor, com 16,5cm de comprimento total, do que as f?meas (20,5cm). Durante o per?odo reprodutivo, o fator de condi??o e ?ndice gonadossom?tico (IGS) de L. piau foram correlacionadas negativamente. A esp?cie apresenta ov?citos grandes com uma alta fecundidade (54,966 em m?dia), com desenvolvimento ovocit?rio sincr?nico e desova total

The quantification and description of sea surface temperature (SST) is critically important because it can influence the distribution, migration, and invasion of marine species; furthermore, SSTs are expected to be affected by climate change. Recent research indicates that there has been a warming trend in ocean temperatures over the last 50 years. Hence, we sought to identify and demonstrate how a particularly germane SST dataset can be used within the scope of global climate change research. For this project we assembled a 29-year nearshore time series of mean monthly SSTs along the North Pacific coastline, as well as mean monthly SSTs for ice-free regions of the Arctic, using remotely-sensed satellite data collected with the Advanced Very High Resolution Radiometer (AVHRR) instrument. By providing detailed information concerning both dataset generation and data limitations, we aimed to make these data comprehensible to an expanded audience concentrating on life sciences rather than the traditionally physical science-based community. Furthermore, by making these data freely and publically available in multiple formats, including GIS (geographic information systems) layers, we expand their visibility and the extent of their use. We then used the dataset to describe SST patterns of nearshore (< 20 km offshore) regions of 16 North Pacific ecoregions, and of ice-free regions of 20 Arctic ecoregions, as delineated by the Marine Ecoregions of the World (MEOW) hierarchical schema. Our work creates a better understanding of present temperature regimes in these critically sensitive areas, from which we can draw several basic conclusions. 1) AVHRR SST measurements alone are sufficient to identify temperature patterns pertinent to determining health of ecosystems; 2) Within the nearshore North Pacific, ecoregions along the California Current System are most vulnerable to habitat-altering SST changes; 3) sea ice distribution is a major factor affecting SSTs in Arctic ecoregions, causing concern for the welfare of Arctic species. / Graduation date: 2012

Abstract in English, Afrikaans and Sesotho / Scuba diving is a popular marine recreational activity along the eastern and southern coast of Africa. This region is characterised as the East African Marine Ecoregion (EAME) and is known for its richness in marine fauna and flora, including some of the Indian Ocean‟s most diverse and abundant coral reef ecosystems, making it a popular destination for scuba divers. The future of the scuba diving industry has come under threat as a result of environmental, social, political and economic impacts, and there is a need to better understand how these external risks impact on scuba diving tourism businesses in the EAME. Empirical evidence suggests that external risks, both international and domestic, have an effect on the tourism industry as a whole. However, limited research has been conducted on the impact of such external risks on the dive tourism industry specifically. Existing research has also focused extensively on environmental risks rather than on how external risks of a political, economic and social nature affect dive operator sustainability in the EAME. Most studies have also focused on the demand side (divers) as opposed to the supply side (dive operators). In addition, as dive tourists have greater flexibility to change their destination should risks arise, this threatens the success of dive operators in higher risk areas. To address these problems, the primary objective of the research undertaken sought to comprehensively identify the impact of external risks (environmental, economic, social and political) on dive operators in four countries within the EAME from a supply-side perspective. In order to achieve the primary objective, the following secondary objectives were achieved: 1. Identified scuba diving tourism operators in the EAME and their scope of operation. 2. Determined the external risks most relevant to dive operators in the EAME and assessed their level of impact. 3. Compared the individual external risks experienced by each of the countries in the EAME (Kenya, Tanzania, Mozambique and South Africa) using a cross-case analysis. 4. Assessed the perception of dive operators regarding whether external risks would influence a dive tourists decision to travel to the dive operators area of operation in the EAME ii The study consisted of two phases. Phase 1 comprised structured interviews with a select group of dive operators to gain insight into the external risks most prevalent in the scuba diving industry, as well as to assist in developing a quantitative structured survey (Phase 2), which was subsequently completed by dive operators in Kenya, Tanzania, Mozambique and South Africa. Data was imported into SPSS for quantitative statistical analysis. From the primary data collected, the major findings from this study determined that current economic and political risks have the greatest impact on dive operators in the EAME, and this trend is expected to continue. Environmental degradation of coral reefs, while not seen as a threat at present, constitutes a key threat for the near future. The greatest influences expressed in terms of risk categories impacting on dive tourism are domestic economic risks, international economic risks, domestic political risks and international political risks. A cross-case analysis conducted on the four countries concluded that external risks have varying effects within the different countries. Finally, the results indicated that external risks significantly influence a dive tourist's decision to travel to the EAME. By identifying and assessing the external risks that have an impact on dive operators in the EAME, this research contributes to knowledge on the dive tourism industry in the EAME, as well as dive tourism further afield and the wider field of tourism management. The study's findings create awareness of the effect that external risks have on dive operators in the region. A conceptual framework was developed which encompasses external risks in the scuba diving industry. Risk radars, risk maps and colour-coded tables were further outputs this study which can assist businesses, society and economies in responding to current and future threats and crises in a more informative and intuitive way. This can be achieved by implementing risk management strategies to mitigate or reduce exposure to external risks; strengthening stakeholder involvement along the tourism value chain; and stressing the need for government involvement towards the protection of the environment and promotion of small business growth in the region. Future research can include a wider view of the marine tourism industry and other areas of the Blue Economy. / Skubaduik is 'n gewilde mariene ontspanningsaktiwiteit langs die oos- en suidkus van Afrika. Hierdie streek staan bekend as die Oos-Afrika Mariene Ekostreek (East African Marine Ecoregion, EAME) en is bekend vir sy rykheid aan mariene fauna en flora, insluitende sommige van die Indiese Oseaan se mees diverse en welige koraalrif-ekostelsels, wat dit 'n gewilde bestemming vir skubaduikers maak. Die toekoms van die skubaduikbedryf word bedreig weens die impak van omgewings-, sosiale, politieke en ekonomiese gebeure, en daar is 'n behoefte om beter te verstaan hoe hierdie eksterne risiko's skubaduiktoerisme-besighede in die EAME beïnvloed. Empiriese bewyse suggereer dat eksterne risiko's, internasionaal sowel as plaaslik, 'n invloed op die toerismebedryf as 'n geheel het. Beperkte navorsing is egter gedoen oor die impak van sulke eksterne risiko's op spesifiek die duiktoerisme-bedryf. Bestaande navorsing het ook uitvoerig gefokus op omgewingsrisiko's eerder as hoe eksterne risiko's van 'n politieke, ekonomiese en sosiale aard duik-operateur-volhoubaarheid in die EAME beïnvloed. Die meeste studies het ook gefokus op die aanvraagkant (duikers) in teenstelling met die aanbodkant (duik-operateurs). Verder, omdat duiktoeriste meer buigsaamheid het om hulle bestemming te verander indien risiko's voorkom, bedreig dit die sukses van duik-operateurs in hoë-risiko-gebiede. Om hierdie probleme te hanteer is die primêre doel van die navorsing wat gedoen is om op omvattende wyse die impak van eksterne risiko's (omgewing, ekonomies, sosiaal en polities) op duik-operateurs in vier lande in die EAME te identifiseer uit 'n aanbodkant-perspektief. Om die primêre doelwit te behaal, is die volgende sekondêre doelwitte bereik: 1. Skubaduik-toerisme-operateurs in die EAME en hulle operasionele omvang is geïdentifiseer. 2. Die eksterne risiko's wat die relevantste vir duik-operateurs in die EAME is, is bepaal en hulle vlak van impak is geassesseer. 3. Die individuele eksterne risiko's wat deur elkeen van die lande in die EAME (Kenia, Tanzanië, Mosambiek en Suid-Afrika) ervaar is, is vergelyk deur die gebruik van 'n kruisgeval-analise. 4. Die persepsie van duik-operateurs wat betref of eksterne risiko's 'n duiktoeris se besluit sal beïnvloed om na die duik-operateur se operasionele gebied in die EAME te reis, is geassesseer. Die studie het uit twee fases bestaan. Fase 1 het gestruktureerde onderhoude met 'n geselekteerde groep duik-operateurs behels om insig te kry in die eksterne risiko's wat die algemeenste in die skubaduikbedryf voorkom, en om te help om 'n kwantitatiewe gestruktureerde peiling (fase 2) te ontwikkel, wat gevolglik deur duik-operateurs in Kenia, Tanzanië, Mosambiek en Suid-Afrika voltooi is. Data is ingevoer in SPSS vir kwantitatiewe statistiese analise. Uit die primêre data wat ingesamel is, het die belangrikste bevindings van hierdie studie bepaal dat die huidige ekonomiese en politieke risiko's die grootste impak op duik-operateurs in die EAME het, en daar word verwag dat hierdie tendens sal voortduur. Die omgewingsagteruitgang van koraalriwwe, hoewel dit nie tans as 'n bedreiging beskou word nie, is 'n sleutelbedreiging vir die nabye toekoms. Die grootste invloede wat uitgedruk is as risiko-kategorieë wat 'n invloed op duiktoerisme het, is plaaslike ekonomiese risiko's, internasionale ekonomiese risiko's, plaaslike politieke risiko's en internasionale politieke risiko's. 'n Kruisgeval-analise wat op die vier lande uitgevoer is, het bevind dat eksterne risiko's wisselende uitwerkings binne die verskillende lande het. Laastens het die resultate aangedui dat eksterne risiko's 'n duiktoeris se besluit om na die EAME te reis, aansienlik beïnvloed. Deur die eksterne risiko's te identifiseer en te assesseer wat 'n impak op duik-operateurs in die EAME het, dra hierdie navorsing by tot kennis oor die duiktoerismebedryf in die EAME, asook duiktoerisme verder weg en die wyer veld van toerismebestuur. Die studie se bevindings skep 'n bewustheid van die uitwerking wat eksterne risiko's op duik-operateurs in die streek het. 'n Konseptuele raamwerk is ontwikkel wat eksterne risiko's in die skubaduikbedryf omvat. Risiko-radars, risiko-kaarte en tabelle wat volgens kleur gekodeer is, was verdere uitsette van hierdie studie wat besighede, die gemeenskap en ekonomieë kan help om te reageer op huidige en toekomstige bedreigings en krisisse op 'n meer ingeligte en intuïtiewe manier. Dit kan bereik word deur risikobestuurstrategieë te implementeer om blootstelling aan eksterne risiko's te mitigeer of te verminder; belanghebberbetrokkenheid op die toerismewaardeketting te versterk; en om die behoefte vir regeringsbetrokkenheid by die insluit. / Ho sesa tlasa metsi a lewatle ke mosebetsi o tsebahalang haholo wa boithabiso ba lewatle haufi le mabopo a ka botjhabela le borwa ba Afrika. Sebaka sena se kgethollwa e le lefatshe la bophelo ba mawatle a Afrika Botjhabela (EAME) mme se tsejwa ka leruo la sona la diphoofolo tsa lewatle le dimela, ho kenyelletsa le tse ding tsa diphedi tse fapaneng tsa lewatle la Indian, e leng se etsang hore e be sebaka se tumeng bakeng sa batho ba sesang tlasa lewatle. Bokamoso ba indasteri ya ho tola tlasa lewatle bo kotsing ka lebaka la tshusumetso ya tikoloho, kahisano, dipolotiki le moruo, mme ho na le tlhokahalo ya ho utlwisisa hantle hore dikotsi tsena tsa kantle di ama jwang dikgwebo tsa bothori bo amanang le ho sesa tlasa lewatle EAME (Mabatoweng a Afrika Botjhabela a diphedi tsa mawatle). Bopaki bo hlakileng bo fana ka maikutlo a hore dikotsi tsa kantle, tsa matjhaba le tsa lehae, di na le tshwaetso indastering ya bohahlauli ka kakaretso. Leha ho le jwalo, dipatlisiso tse fokolang di ile tsa etswa mabapi le sefutho sa dikotsi tse jwalo tsa kantle indastering ea bohahlaudi ba ho sesa ka ho kgetheha. Dipatlisiso tse teng di boetse di tsepamisitse maikutlo haholo ka dikotsi tsa tikoloho di sa shebe hore na dikotsi tsa kantle tsa dipolotiki, tsa moruo le tsa kahisano di ama jwang ho tsitsisa tshebetso ho EAME. Diphuputso tse ngata di boetse di tsepame lehlakoreng la tlhokahalo (disesi) ho fapana le lehlakore la diphallelo (batho ba sesang). Ho phaella moo, jwalo ka ha disesi tsa bahahlaudi di ena le maemo a mangata a ho fetola dibaka tsa bona ha ho hlaha dikotsi, sena se senya katleho ya disesi dibakeng tse nang le dikotsi tse ngatanyana. Ho rarolla mathata ana, sepheo se ka sehloohong sa dipatlisiso tse entsweng di ile tsa leka ho lemoha ka ho hlaka sefutho sa dikotsi tsa kantle (tikoloho, moruo, kahisano le dipolotiki) ho disesi dinaheng tse nne tse ka hare ho EAME ho tloha lehlakoreng la phepelo. E le ho finyella sepheo se ka sehloohong, dipheo tse latelang di ile tsa fihlellwa: 1. Ho kgetholla basebeletsi ba bahahlaudi ba ho sesa lebatoweng la EAME le tsela ya tshebetso ya bona. 2. Ho etsa qeto ya dikotsi tse ka ntle tsa bohlokwa ho tsamaisa ba disesi ho EAME le ho hlahloba boemo ba tsona ba tshusumetso. 3. Ho bapiswa dikotsi tse ka ntle tsa naha ka nngwe ho EAME (Kenya, Tanzania, Mozambique le Afrika Borwa) ho sebedisa dintlha tsa ho hlahloba diketsahalo. 4. Hlahloba maikutlo a disesi mabapi le hore na dikotsi tse ka ntle di tla susumetsa qeto ya bahahlaudi ba ho etela sebakeng seo ba sebetsang ho sona ho EAME Thuto e ne e ena le mekgahlelo e mmedi. Mokgahlelo wa 1 o ne o ena le dipuisano tse hlophisitsweng le sehlopha se kgethilweng sa basebetsi ba disesi ho utlwisisa dikotsi tse ka ntle tse atileng haholo indastering ya ho sesa, le ho thusa ho ntlafatsa tlhahlobo e entsweng ka bongata (Phase 2), e ileng ya qetella e phethilwe ke basebetsi ba disesi Kenya, Tanzania, Mozambique le Afrika Borwa. Lesedi le ile la kenngwa ka SPSS bakeng sa tlhahlobo ya dipalopalo. Ho tswa leseding la motheho le bokelletsweng, diphuputso tse kgolo tsa thuto ena di bontshitse hore dikotsi tsa moraorao tsa moruo le tsa lipolotiki di na le tshusumetso e kgolo ho ba sebetsang e le basebetsi ba disesi EAME, mme mokgwa ona o lebeletswe hore o tswele pele. Ho senyeha ha tikoloho ya dimela/diphedi tsa lewatle, ha ho sa nkuweng e le tshoso hona jwale, ke tshoso e ka sehloohong bakeng sa nako e tlang. Tshusumetso e matla ka ho fetisisa e hlalositsweng ka mekgahlelo ya dikotsi tse amang tsela ya ho etela dibaka tsa bohahlaudi ke dikotsi tsa moruo wa lehae, dikotsi tsa matjhaba tsa moruo, dikotsi tsa dipolotiki tsa lehae le dikotsi tsa matjhaba tsa dipolotiki. Phuputso e entsweng dinaheng tse nne e qetile ka hore dikotsi tsa ka ntle di na le diphello tse fapaneng dinaheng tse fapaneng. Qetellong, diphello di bontshitse hore dikotsi tsa ka ntle di susumetsa haholo qeto ya mohahlaudi wa ya sesang tlasa lewatle ho etela EAME. Ka ho kgetholla le ho hlahloba dikotsi tse ka ntle tse nang le tshwaetso basebetsing ba disesi EAME, dipatlisiso tsena di tlatsetsa tsebong lefapheng la bohahlaudi ba ho ho sesa tlasa lewatle dibakeng tsa EAME, ha mmoho le bahahlaudi ba ho sesa ka ho phatlalla tsamaisong ya bohahlaudi. Diphuputso tsa thuto di etsa hore ho be le tlhokomediso ya phello ya ka moo dikotsi tse ka ntle di nang le kameho disesing sebakeng seo. Ho na le moralo o ileng wa etswa o kenyeletsang dikotsi tsa kantle indastering ya ho sesa tlasa lewatle. Diwaelese tse nkgellang dikotsi, dimmapa tsa dikotsi le ditafole tse nang le mebala di ne di boetse di hlahisa thuto ena e ka thusang dikgwebo, setjhaba le moruo ho arabela dikotsing tsa moraorao le tsa nakong e tlang ka ditsela tse rutang le tse nang le tsebo. Sena se ka fihlellwa ka ho kenya tshebetsong maano a tsamaiso ya kotsi bakeng sa ho fokotsa ho pepeseha dikotsing tsa kantle; ho matlafatsa tshebetsong ya bankaseabo motjheng wa bohlokwa wa bohahlaudi; le ho totobatsa tlhokahalo ya ho nka seabo ha mmuso ho sireletsa tikoloho le tshehetso ya kgolo ya dikgwebo tse nyenyane sebakeng seo. Phuputso ya nako e tlang e ka kenyelletsa pono e pharaletseng ya indasteri ya bahahlaudi ba lewatle le dibaka tse ding tsa Blue Economy. / Environmental Sciences / M. Com. (Tourism Management)