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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
191

Land pollution and population density : the case of Kwekwe City residential areas, Zimbabwe

Chatsiwa, Jaison 02 1900 (has links)
In most developing countries, the problem of inefficient municipal solid waste management (MSWM) is endemic. The problem is manifested by heaps of uncollected solid waste found on open areas and by the street sides. This dissertation examines the relationship between land pollution and population density resulting from solid waste generation in the City of Kwekwe in Zimbabwe. Questionnaires and interviews were conducted to 375 randomly selected households in low, medium and high density residential suburbs. The household survey was triangulated with field observations, key informant interviews and secondary data sources. The average household size in high, medium and low density residential areas was 11, 8 and 5 people respectively. The study revealed that the amount and composition of solid waste generated varied according to household size, income and education levels of residents. The higher the population density, the more the solid waste produced. However, waste generated was not carried to the dumpsites for disposal. Also the higher the income, the higher the amount of solid waste produced, although residents with high income were able to ferry their wastes to the dumpsites hence less land pollution. The solid waste generation rate in high density areas was 0.04 kg/capita day, in medium density areas was 0.35 kg/capita/day and in low density areas were 0.84 kg/capita/day. It was also observed that among high income earners, the educated people produced more waste than low income earners. However, the low income earners and the less educated people could not take care of their environment to limit roadside and open space littering. However, lack of public awareness coupled with inefficient and ad hoc waste management system continue make provision of effective solid waste management services illusive. Based on the research findings, it is suggested sound environmental stewardship amongst residents will limit land pollution in the city of Kwekwe. / Environmental Sciences / M.A. (Environmental Management)
192

Land pollution and population density : the case of Kwekwe City residential areas, Zimbabwe

Chatsiwa, Jaison 02 1900 (has links)
In most developing countries, the problem of inefficient municipal solid waste management (MSWM) is endemic. The problem is manifested by heaps of uncollected solid waste found on open areas and by the street sides. This dissertation examines the relationship between land pollution and population density resulting from solid waste generation in the City of Kwekwe in Zimbabwe. Questionnaires and interviews were conducted to 375 randomly selected households in low, medium and high density residential suburbs. The household survey was triangulated with field observations, key informant interviews and secondary data sources. The average household size in high, medium and low density residential areas was 11, 8 and 5 people respectively. The study revealed that the amount and composition of solid waste generated varied according to household size, income and education levels of residents. The higher the population density, the more the solid waste produced. However, waste generated was not carried to the dumpsites for disposal. Also the higher the income, the higher the amount of solid waste produced, although residents with high income were able to ferry their wastes to the dumpsites hence less land pollution. The solid waste generation rate in high density areas was 0.04 kg/capita day, in medium density areas was 0.35 kg/capita/day and in low density areas were 0.84 kg/capita/day. It was also observed that among high income earners, the educated people produced more waste than low income earners. However, the low income earners and the less educated people could not take care of their environment to limit roadside and open space littering. However, lack of public awareness coupled with inefficient and ad hoc waste management system continue make provision of effective solid waste management services illusive. Based on the research findings, it is suggested sound environmental stewardship amongst residents will limit land pollution in the city of Kwekwe. / Environmental Sciences / M.A. (Environmental Management)
193

Monitoring European pine martens (Martes martes) in Scottish forested landscapes

Kubasiewicz, Laura M. January 2014 (has links)
Monitoring the distribution, abundance and demography of species is vital to ensure that conservation efforts are appropriate and effective. Monitoring enables evaluation of responses to natural or human disturbance, highlights the need for management interventions and enables these interventions to be assessed and refined. The methods used largely depend on the specific aim of monitoring and behaviour of the target species, as well as the time and spatial scale that monitoring is required to cover. The European pine marten (Martes martes) is one of few remaining mammalian predators native to the UK. Since persecution in the early 19th century resulted in their near extinction, pine martens have recovered part of their former range in Scotland. Their recent recovery and an overlap in territory with vulnerable prey species such as the capercaillie (Tetrao urogallus) make the collection of accurate baseline data and subsequent monitoring of population trends vital for conservation efforts. Faecal counts have traditionally been used to provide a relative measure of population density for pine marten. In most cases, absolute measures of population density require individual identification. Non-invasive genotyping can provide this information but the quality of DNA from these samples is often poor. Here, the process is refined for pine marten faeces (scats) and hair samples. DNA degradation increased significantly for scats exposed to rainfall, with the rate of DNA amplification success reduced by 38% over a 16 day period. Success rates for hair samples were higher when more hair follicles were included in the analysis. Population densities were estimated for three forests in Scotland using a robust combination of non-invasive genotyping of hair samples and spatially explicit capture recapture modelling. Population density estimates of 0.07 (95% CI 0.03 - 0.16) to 0.38 km-2 (95% CI 0.11 - 1.07) were obtained which are within the range of previous estimates for forests elsewhere in Scotland. The first attempt to quantify the relationship between traditional scat counts and home range size was then conducted; a significant negative correlation exists but only when population density is relatively low. Previous studies suggest that pine martens in Western Europe are less forest dependent than those in Eastern Europe. Results from this thesis support this, with populations at the highest density found at sites with intermediate forest cover. This tolerance of lower forest cover is also apparent in the diet. Despite a preference for Myodes voles in populations in Eastern Europe, those in Western Europe show a strong preference for Microtus voles as well as a higher level of frugivory. We assess the autumn diet of four populations in Scotland assess the effect of forest cover and sex on the diet. There was no evidence of differential consumption of Microtus voles or birds between the sexes. Our analysis shows that frugivory is influenced by forest fragmentation, with a 5-fold increase in the occurrence of fruit (from 2% to 10%) as forest cover increased from 4% to 47%. Diversionary feeding has been suggested as a management technique to reduce the depredation of capercaillie by pine martens. This thesis presents the first attempt to quantify the success and cost-efficacy of diversionary feeding for a range of problems (crop damage, threatened safety, livestock depredation) across 30 experimental trials. The strategy proved more effective when targeted towards food-limited populations, and when aiming to alleviate habitat damage or risks to human safety rather than depredation. A novel decision-making framework was developed to aid managers with the initial planning of the strategy and its subsequent implementation within an adaptive format. Further to this, the feasibility of using diversionary feeding with a view to reduce the depredation of capercaillie by pine martens was assessed. Questionnaire responses were collected from people who have provided food for pine martens throughout Scotland. A positive reaction to food was observed, with 58% of respondents reporting that initial visits occurred within one week of placement and 46% reporting that subsequent visits were received daily. These results suggest that diversionary feeding may be a viable option for pine marten management, although testing of its impact on capercaillie productivity would be required.
194

Diagnóstico das populações de aves e mamíferos cinegéticos do Parque Estadual da Serra do Mar, SP, Brasil. / Diagnostic of game birds and mammals populations of Serra do Mar State Park, SP, Brazil.

Marques, Renato Matos 20 December 2004 (has links)
O presente trabalho avaliou não somente a abundância e densidade de mamíferos e aves cinegéticas na área do Parque Estadual da Serra do Mar (PESM), mas também identificou fatores que influenciaram a ocorrência e distribuição destas espécies. O PESM tem ao todo 3.150 km2 e é o maior remanescente de florestas contínuas de Mata Atlântica no Brasil. Foram percorridos 633,55 km em 15 trilhas distribuídas em três núcleos do setor norte do PESM. Foram obtidas 184 visualizações, tendo sido registradas 11 espécies de mamíferos e 6 espécies de aves cinegéticas durante os censos, num total de 77 encontros com mamíferos e 107 com aves. Dentre as aves cinegéticas com maior abundância destaca-se o jacu Penelope sp. (0,99 visualizações/10 km) e dentre os mamíferos o esquilo Sciurus aestuans (0,48 visualizações/10 km). As espécies apresentaram padrões diferenciados de uso do habitat, padrão de atividades e ocorrência nas áreas avaliadas. Através da análise de correspondência canônica (CCA) dos fatores ambientais foi possível determinar que de maneira geral as espécies de aves apresentamse correlacionadas com uma maior disponibilidade de frutos carnosos, enquanto que as espécies de mamíferos apresentam-se correlacionadas com parâmetros de estrutura física da floresta tais como cobertura de dossel, densidade arbórea e densidade de outras palmeiras que não o palmito, este último principalmente para o queixada (Tayassu pecari). A caça se mostrou um fator que afeta negativamente a maioria das espécies sendo que seu efeito somente não foi observado para S. aestuans e Penelope sp. que, ao que tudo indica, não são espécies intensamente caçadas nas áreas avaliadas. A partir das densidades obtidas foram realizadas estimativas populacionais para as áreas de estudo e extrapolações para todo o PESM. Considerando-se apenas 500 indivíduos como o número mínimo necessário de indivíduos para garantir a viabilidade destas populações foi possível perceber que as áreas estudadas, avaliadas separadamente, não seriam capazes de garantir a manutenção de boa parte das espécies. Quadro este agravado quando considerados valores ainda maiores de população mínima viável necessária. Contudo, para todos os cenários avaliados dados indicam que maiores seriam as chances de manutenção das espécies quando considerado todo o setor norte do parque, área formada pelos três núcleos avaliados, e principalmente o PESM como um todo. Este fat reforça a importância da conectividade entre estas áreas e a manutenção de grandes blocos de matas contínuas. O PESM pode ser considerado uma das mais importantes áreas para a preservação de espécies cinegéticas, sendo a área estratégica no contexto de criação de um corredor ecológico na região, devido principalmente a sua riqueza faunística, qualidade dos remanescentes existentes, presença de espécies raras e ameaçadas de extinção, localização biogeográfica e também por seu gradiente altitudinal. / The aim of this work was to estimate the abundance, diversity and population size of game birds and mammals from the rain forest at Serra do Mar State Park (Parque Estadual da Serra do Mar - PESM), and to identify the variables which influence the ocurrence and distribution of those species. The PESM has 3.150 km2 and is the major continuous remaining of Atlantic Forest in Brazil. A total of 633,55 km census using line transect method, distributed on 15 trails on the north-sector of PESM, resulted in 184 observations, which 77 of those were encounters with game mammals and 107 with birds. Eleven species of mammals and six of birds were recorded during the census. Among game birds the most abundant was the guan, Penelope spp. (0,99 encounters/10 km), and among the game mammals was the squirrel, Sciurus aestuans (0,48 encounters/10 km). The species presented different habitat uses, activity and ocurrence patterns, but when analysing the environmental variables with canonical correspondence analysis (CCA) we detected that the birds were correlated with fruit aviability, while mammals were more correlated to the vegetation structure, such as canopy cover, arboreal density and palms (not palmito) density, this last one specially to the whitelipped- peccaries (Tayassu pecari). The hunting pressure affected negatively most of the species, except for S. aestuans and Penelope spp., which seems to not be intensively hunted at the study areas. Using the densities obtained we estimated the remaining population to the study areas and also to the different scenarios proposed. Even considering only 500 as a minimum number of individuals necessary to guarantee the viability of those populations, the study areas, when analyzed separally, could not maintain most of the game species. It does get worst when considering higher numbers of minimum viable population. Moreover, the results indicate better chances of maintaining populations of the species when considering the area of the north-sector and higher chances when considering the entire park. This fact regards the importance of the connectivity between these areas and the necessity of maintaining large continuous block of forests. PESM can be considered one of the most important areas for the conservation of game species and it’s a strategic area in a context of an ecological corridor, due to it’s richness, quality of forest remains, presence of rare and threatened species, biogeographic localization and also by the altitudinal gradient.
195

Densidade populacional e seleção de habitat pelo mutum-do-sudeste, Crax blumenbachii, na Reserva Natural Vale, Linhares, Espírito Santo / Assessing the population status and habitat relations of the Red-billed Curassow Crax blumenbachii in a Brazilian Atlantic Forest fragment

Amorim, Fernanda Alves de 11 November 2014 (has links)
O mutum-do-sudeste é endêmico da Mata Atlântica de baixada e foi extinto de quase toda sua distribuição original devido ao desmatamento e a caça. Hoje é listado como ameaçado e a falta de conhecimento sobre sua ecologia dificulta o manejo da espécie. Este trabalho teve como objetivo estimar a densidade populacional do mutum-do-sudeste na Reserva Natural Vale (RNV) através do método de transecção linear. Os registros feitos durante as amostragens também foram utilizados para verificar a existência de seleção de habitat por meio da comparação de áreas onde a espécie foi registrada com áreas aleatórias onde nunca obtivemos registros. A estimativa populacional obtida mostrou a existência de uma razão sexual desviada em relação aos machos que parecia estar relacionada a diferenças de comportamento entre os sexos, devido aos poucos registros de fêmeas. Para confirmar nossos resultados, utilizamos dados de armadilhas fotográficas que foram utilizadas para estudar onças na reserva. Estes dados confirmaram um número maior de machos na população, porém menos acentuado do que o encontrado nos transectos, comprovando que o comportamento discreto das fêmeas afetou nossa amostragem. Combinando os dados dos dois métodos obtivemos a estimativa de 1.6 indivíduos/Km2. As análises de seleção de habitat confirmaram a relação positiva do mutum-do-sudeste com matas altas e sub-bosque denso, e mostraram que o mutum-do-sudeste tem menor probabilidade de ocorrência em áreas com abundância de árvores mortas em pé, troncos em decomposição e serapilheira profunda. Tal influencia negativa provavelmente se deve a aspectos relacionados à sua dieta e a baixa tolerância a habitats que sofreram distúrbio. As informações contidas neste trabalho servirão de base para guiar o manejo de populações selvagens e futuros projetos de reintrodução. Além disso, estudos futuros devem considerar as diferenças de comportamento entre os sexos para que os dados sejam analisados de forma correta, evitando assim, erros que podem afetar diretamente o manejo da espécie. / The Red-billed Curassow was formerly found throughout the lowland Brazilian Atlantic Forest but is now extinct across most of its former range due to habitat loss and hunting pressure. Althought classified as globally threatened, there is still a chronic lack of information on Red-billed Curassows\' biology hindering efforts to mitigate the impacts of anthropogenic threats. We investigated population size and habitat relations of Red-billed Curassows at Vale Nature Reserve (VNR) using line transect and presence/absence method. Line transects results showed a male skewed sex ratio that appeared to be related to different behavivour between sexes as we recorded a low number of females. To evaluate any bias in the estimates of sex ratio from line transect we used data from a camera trap survey designed to monitor jaguars at the reserve. Camera trap data confirmed the existence of a male skewed sex ratio in the population but less pronounced than the one found on line transects, showing that different behavior between sexes affected our estimates. Using the sex ratio calculated with camera trap data we were able to estimate 1.6 individuals/Km2. The habitat assessment showed a positive relation of the Red-billed Curassow with taller forests and dense undergrowth. The abundance of snags, decaying log and leaf litter depth, negatively influenced Red-billed Curassows\' occurrence and appear to be related to its mainly frugivorous diet and low tolerance to habitat disturbances. Our study provides critical baseline information about an important population of Red-billed Curassows and will serve to guide management strategies and future reintroduction attempts. It also reveals that survey efforts must take into account sexual differences in behaviour to increase the reliability of modeled estimates. Failing to take these considerations into account may lead to misleading inferences from data, and impact management strategies for a seriously threatened species.
196

Future Risk from the Ae. aegypti Vector: Modeling the Effects of Climate Change and Human Population Density on Habitat Suitability

Obenauer, Julie, Quinn, Megan, Joyner, Andrew, Li, Ying 11 April 2017 (has links)
Introduction: The Aedes aegypti mosquito is responsible for the transmission of Yellow Fever, Dengue, Chikungunya and Zikavirus, making it a deadly vector and global public health threat. Zikavirus and Chikungunya, which were previously restricted to smaller geographic areas, have both appeared in the Western Hemisphere in the past three years and spread to areas where A. aegypti are present. This means that the pathogens have now entered areas in which the population has no previous immunity, which can lead to extensive outbreaks and epidemics. As the effects of global climate change become apparent, the areas of the globe that are suitable for inhabitance by A. aegypti may change. Additionally, this vector prefers human hosts for blood meals and requires standing water to breed, which is often created by water storage containers. This means that increasing urbanization and human population density are likely to put populations at higher risk of exposure to this vector. Methods: To create maps of the future risk of exposure to Aedes aegypti globally, species occurrence data for the vector and the Maxent modeling approach were used. Current and projected climate data were downloaded from WorldClim.org for the four representative concentration pathways (RCPs) used to model future climate change. Human population density, projected to 2050, the same timeframe as the future climate data, were used to model changes in human populations. To identify areas at high risk for future presence of A. aegypti populations, current and future models were compared across areas with at least a 50% probability of increased risk. These results where then used to create maps displaying high risk areas. Results: The AUC, an indicator of model fit, signaled that the models had high predictive power. However, high omission rates indicated that the trade-off of risk mapping may be a need to decrease probability thresholds below 50% to capture the full at-risk population. Future high-risk areas were most often those surrounding current cities, which supports the idea that the combination of urbanization and increasing human population density will work synergistically to increase the disease burden within and around urban centers. Additionally, expansion at the current geographic margins of this species shows that incursion into currently non-endemic areas is possible. Conclusions: Urban and peri-urban populations are likely to be at higher risk of exposure compared to rural areas due to global climate change and changes in population density. Attempts to model expansion of vector habitats should consider how these human population characteristics will change the risk to populations and how to best identify the areas at highest risk. Thresholds for the probability of a population being at risk of exposure to a vector may need to be different from those required to determine whether or not a habitat is suitable for a species. Appropriately determining which areas are high-risk results in maps and models can then be used to identify areas where climate change mitigation and vector control efforts are likely to have the highest impacts.
197

Including Human Population Characteristics in Ecological Niche Models for Aedes aegypti when Modeling Projected Disease Risk due to Climate Change

Obenauer, Julie, Quinn, Megan, Li, Ying, Joyner, Andrew 07 April 2017 (has links)
The Aedes aegypti mosquito is responsible for transmission of four vector-borne diseases that cause considerable global morbidity and mortality. Projections of the future effects of global climate change indicate that expansion of this species due to changing habitats is possible. Furthermore, since A. aegypti is highly dependent on human populations for feeding and egg-laying sites, changing human population characteristics are likely to alter the risk of exposure for humans based on geographic location. This study aims to create future potential risk maps for human exposure to A. aegypti using human population density as a predictor. Using current population density data and future growth trajectories, high-resolution human population density forecasts were created for 2050, then included as variables in ecological niche models developed using Maxent. Species occurrence data and high resolution climate data for current and future conditions (best and worst case scenarios) were included in the model, as well. Model fit indices and variable contributions indicated that the inclusion of human population density improves model accuracy for A. aegypti. Risk maps created by these models showed that areas currently adjacent to large cities within endemic regions, such as central Africa and western Brazil, are likely to see the greatest increase in risk to human populations. This corroborates current projections on increasing urbanization in the future and suggests that these models can be used to target interventions in high risk areas.
198

Vom Aussterben bedroht oder anpassungsfähig? - Der Koboldmaki <i>Tarsius dianae</i> in den Regenwäldern Sulawesis / Endangered or Adaptable? - The Dian's Tarsier <i>Tarsius dianae</i> in Sulawesi's Rainforests

Merker, Stefan 06 May 2003 (has links)
No description available.
199

The conservation biology of the leopard (Panthera pardus)in Gabon / Status, threats and strategies for conservation / Der Schutzstatus des Leoparden (Panthera pardus) in Gabun / Bestände, Gefährdungen und Strategien zum Schutz

Henschel, Philipp 21 January 2009 (has links)
No description available.
200

Altitudinal Effects on The Behavior and Morphology of Pygmy Tarsiers (Tarsius pumilus) in Central Sulawesi, Indonesia

Grow, Nanda Bess 16 December 2013 (has links)
Pygmy tarsiers (Tarsius pumilus) of Central Sulawesi, Indonesia are the only species of tarsier known to live exclusively at high altitudes. This study was the first to locate and observe multiple groups of this elusive primate. This research tested the hypothesis that variation in pygmy tarsier behavior and morphology correlates with measurable ecological differences that occur along an altitudinal gradient. As a response to decreased resources at higher altitudes and the associated effects on foraging competition and energy intake, pygmy tarsiers were predicted to exhibit lower population density, smaller group sizes, larger home ranges, and reduced sexually selected traits compared to lowland tarsiers. Six groups containing a total of 22 individuals were observed. Pygmy tarsiers were only found between 2000 and 2300 m, indicating allopatric separation from lowland tarsiers. As expected, the observed pygmy tarsiers lived at a lower density than lowland tarsier species, in association with decreased resources at higher altitudes. The estimated population density of pygmy tarsiers was 92 individuals per 100 ha, with 25 groups per 100 ha. However, contrary to expectation, home range sizes were not significantly larger than lowland tarsier home ranges, and average NPL was smaller than those of lowland tarsiers. The average home range size for the observed pygmy tarsiers was 2.0 ha, and the average nightly path length (NPL) was 365.36 m. Pygmy tarsiers exhibited a nonrandom, clumped distribution near forest edges. While insect abundance and biomass were found to decrease as altitude increased, insect abundance and biomass was higher along anthropogenic edges. Thus, tarsiers within the study area may mitigate the decreased availability of insects at high altitudes by remaining close to forest edges, which in turn may be related to smaller than expected home range sizes. Further, estimates of pygmy tarsier abundance may be inflated because of increased insect abundance along anthropogenic edges. Contrary to the prediction for smaller group sizes as a response to feeding competition, the observed pygmy tarsiers lived in relatively large groups with multiple adult males. However, in support of the prediction for energetic constraints on body proportions, the observed pygmy tarsiers did not exhibit sexually selected traits. The pygmy tarsiers exhibited low sexual dimorphism and small relative testes mass, a trend opposite from lowland tarsier species, which may indicate a constraint on the development of those traits. Considered together, these results suggest that the observed pygmy tarsiers have adapted to life in an environment with limited resources. Future studies should explore the possible contributing effects of seasonality and topography.

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