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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.
151

Densidade, genética e saúde populacional como ferramentas para propor um plano de controle e erradicação de invasão biológica: o caso de Callithrix aurita (Primates) no Parque Nacional da Serra dos Órgãos, RJ, Brasil

Daniel Gomes Pereira 30 June 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A introdução de espécies em locais fora de sua distribuição natural é uma preocupação importante na conservação da biodiversidade. A espécie Callithrix aurita é endêmica das regiões de floresta de altitude da Mata Atlântica do Sudeste do Brasil. Os critérios mais relevantes que a enquadram como espécie ameaçada de extinção são: destruição do habitat, incapacidade de adaptação a florestas secundárias degradadas, declínio populacional, distribuição restrita e introdução de espécies exóticas invasoras. Estes critérios, aliados à evidente raridade, explicam a sua inclusão na Lista Oficial de Espécies da Fauna Brasileira Ameaçadas de Extinção. Os objetivos do trabalho são: estimar o tamanho populacional de C. aurita, C. penicillata e seus híbridos no Parque Nacional da Serra dos Órgãos, avaliar a hibridação entre as espécies por caracteres morfológicos e laboratoriais, verificar o estado de saúde e confirmar a participação de C. aurita na paternidade dos animais capturados, propor um plano de erradicação e de controle de invasão de C. penicillata no Parque. Os tamanhos populacionais das duas espécies de primatas foram estimados através do método Distance Sampling. Um total de sete sagüis foi capturado com armadilhas de captura viva para a contenção física e química e posterior realização dos procedimentos. Para o hemograma, as dosagens bioquímicas e as análises genéticas, o sangue foi recolhido em um tubo de ensaio contendo anticoagulante e mantido em temperatura de refrigeração até o momento da manipulação / processamento das amostras. Callithrix aurita parece estar bem preservada apenas na área do Parque correspondente ao trecho situado no município de Petrópolis. As análises citogenéticas e moleculares dos híbridos são uma ferramenta útil para confirmar se há ou não hibridação, identificando as espécies envolvidas e verificando se há tendência nos retrocruzamentos. Pode-se sugerir que existe uma tendência à diferenciação das espécies e identificação de indivíduos híbridos pelo padrão hematológico e bioquímico, a ser confirmada com uma amostragem maior de animais da espécie C. aurita, preferencialmente da mesma localidade e nas mesmas condições. No caso de C. aurita, as principais recomendações para sua conservação incluem pesquisas para o registro de outras populações em áreas de distribuição livres de invasão, para que se possa avaliar as chances de recuperação populacional e sobrevivência da espécie. A criação de novas Unidades de Conservação deve ser estimulada, assim como estudos mais aprofundados sobre a espécie nos locais já conhecidos de ocorrência, além de um programa seguro de criação em cativeiro. / The introduction of species in places outside their natural distribution is an important concern in biodiversity conservation. Callithrix aurita is endemic in regions of high-altitude forests of the Atlantic forest of southeastern Brazil. The most relevant criteria of fitting as endangered species are: habitat destruction, inability to adapt to degraded secondary forests, population decline, restricted distribution and introduction of invasive alien species. These criteria, coupled with the apparent rarity, explain its inclusion on the Official List of Species of Brazilian Fauna Threatened with Extinction. The objectives are: to estimate the population size of C. aurita, C. penicillata and their hybrids in the Serra dos Órgãos National Park, assess hybridization between species by morphology and laboratory check the health status and confirm the involvement of C. aurita in the fatherhood of trapped animals, propose a plan for eradication and control of invasion of C. penicillata in the Park. The population sizes of the two primate species were estimated by the method "Distance Sampling". A total of seven marmosets were captured with live traps set for the chemical and physical restraint and subsequent completion of the procedures. For the haemogram, the biochemical and genetic analysis, blood was collected in a test tube containing anticoagulant and kept at refrigerator temperature until the moment of handling / processing of samples. Callithrix aurita appears to be well preserved only in the park area corresponding to the portion located in the city of Petrópolis. The cytogenetic and molecular analysis of hybrids are a useful tool to confirm whether or not hybridization, identifying the species involved and seeing if there is a tendency in the backcrosses. One may suggest that there is a tendency for species differentiation and identification of hybrid individuals by standard hematological and biochemical, to be confirmed with a larger sample of the species C. aurita, preferably from the same locality and under the same conditions. In the case of C. aurita, the main recommendations for its conservation research to include the registration of other populations in areas of distribution free of intrusion, so you can evaluate the chances of population recovery and species survival. The creation of new protected areas should be encouraged, as well as more detailed studies on the species already known sites of occurrence, and a safe program of captive breeding.
152

Arbuscular mycorrhizal symbiosis of herbaceous invasive neophytes in the Czech Republic / Arbuscular mycorrhizal symbiosis of herbaceous invasive neophytes in the Czech Republic

ŠTAJEROVÁ, Kateřina January 2009 (has links)
I have studied arbuscular mycorrhizal symbiosis of 44 herbaceous invasive neophytes occuring in the Czech Republic. My results show that about 70% of the examined species are capable to form symbiotic association with arbuscular mycorrhizal fungi (AMF) in the field. To my knowledge, mycorrhizal status of 23 invasive species is reported here for the first time. I predicted, based on the hypothesis of Urcelay & Díaz (2003), that the intensity of AMF in the roots of invasive species will be correlated with that of the native dominant species of invaded plant community, but collected data did not support this hypothesis. In addition, the effects of habitat and community characteristics on the intensity of AMF colonization of the invasive species{\crq} roots were tested. My results show that, at the within-species level, plants in the habitats with higher light and temperature conditions have less colonized roots whereas intensity of mycorrhizal colonization increases with habitat moisture. At the among-species level, invasive species occurring in the habitats with elevated nitrogen availability have higher mycorrhizal colonization of their roots. The effect of nitrogen availability is revealed at the among-species level and stays significant even after phylogenetic correction, suggesting this is an evolutionary adaptation rather than a phenotypic plasticity.
153

Práva imigrantů / Rights of Immigrants

SOUKUPOVÁ, Eva January 2007 (has links)
The Czech Republic encounters problems of immigration after 1989. At present time there are about 2.5% of foreigners in the Czech Republic. This percentage is amongst the lowest within EU, however the predictions for the future are that the number is going to constantly increase. People come to the Czech Republic seeking better conditions for living and want to start a new life here. Therefore part of the government policy should be securing immigrants with equal access and equal opportunities in the labour market, in relation to health as well as social care. A quantitative research in the form of a questionnaire technique was selected in the practical part. Anonymous questionnaires for immigrants and public were used. The research aimed at immigrants was conducted in institutions engaged in helping aliens in Brno, České Budějovice, Hradec Králové, Plzeň and Prague. Total of 120 questionnaires were sent out. The questionnaire's returnability was 49%. The research set was therefore formed by 59 respondents. Research aimed at public was conducted in České Budějovice, Jindřichův Hradec and in Třeboň. Total of 110 questionnaires were handed out and their returnability was 100%. All questionnaires were evaluated and elaborated into percentage figures. Two goals are set in the thesis. To each of the goals two hypotheses were set. Goal 1: Find out the level of immigrants' knowledge about labour law and related regulations to it {--} health insurance, welfare. Hypothesis No. 1: More than half of the questioned immigrants know their rights. Hypothesis No. 2: More than half of the questioned immigrants know to whom they may turn to in case of problem solving. After questionnaire evaluation the first hypothesis was not confirmed and the second hypothesis was confirmed. Goal 2: Find out the level of public awareness of the law status of aliens living in the area of the Czech Republic. Hypothesis No. 1: More than half of the questioned respondents do not know the alien rights living in the area of the Czech Republic. Hypothesis No. 2: More than half of the questioned respondents know the organizations providing support for aliens living in the area of the Czech Republic. After evaluation of the questionnaire the first hypothesis was not confirmed and the second was confirmed.
154

Invasion of alien species on Robben Island : causes and impacts on phylogenetic diversity of native plant communities

Bezeng, Bezeng Simeon 14 August 2012 (has links)
M.Sc. / Invasive species are a considerable threat to ecosystems globally, especially on islands where species diversity can be relatively low. Understanding the drivers of invasion is the first step towards an adequate management plan. Although Darwin’s naturalisation hypothesis has fuelled our understanding in this regard, several studies provided mixed results, suggesting that invasion success might be context-dependent. The main objectives of this study are two-fold: (1) testing Darwin hypothesis on Robben Island, and (2) investigating the relative role of invasive alien plants on phylogenetic diversity (PD) loss in native community. I sampled extensively the flora of the island, and using a Bayesian analysis, I reconstructed its phylogeny based on two plastid DNA loci, rbcLa and matK. I also surveyed a total of 127 plots of 50 x 50 m (i.e. local communities) where species presence/absence was recorded. Analysing phylogenetic patterns of the native and invasive floras at both regional (phylogeny level) and smaller scales (plots level), I found that invasive species are, on average, more distantly related to the native communities, giving strong support to the hypothesis tested. Furthermore I found that native communities have accumulated lower PD than alien communities; and that local communities are more overdispersed than expected. These findings suggest that competitive interactions might be the major ecological forces shaping plant communities, with the possibility of alien being higher competitors than native, and therefore decreasing native plant diversity. The implications of these findings for the recovery of native plants are also discussed. Key words: Invasion biology - Darwin’s naturalisation hypothesis - Phylogenetic diversity - Community structure - Conservation - Robben Island, South Africa.
155

Fyzickogeografické aspekty rozšíření nepůvodních druhů rostlin v CHKO Křivoklátsko / Physical-geographic aspects of alien plant species distribution in the Křivoklátsko Protected Landscape Area

Nováková, Zuzana January 2016 (has links)
Plant invasions are becoming increasingly more discussed issue, primarily due to a negative impact on global biodiversity. It has also an economic impact and it affects human health. It is therefore important to study the introduction of plant species and their distribution, and monitor them in some way. This is particularly applied to protected areas, where rare species of plants are often endangered. In this work were described factors that affect distribution of alien plant species in the level of plant communities, landscape and large territories. For the practical part of the work has been selected the Křivoklátsko PLA as a model area, mainly because of detailed botanical mapping. There were analysed diversity, origin and distribution of alien plant species. Also the effect of selected factors on distribution of alien plant species in the Křivoklátsko PLA were assessed. The average altitude is the strongest factor. The second strongest factor is the fraction of anthropogenic habitats and moderate factor is the habitat diversity. The length of rivers is weak predictor and the length of roads is very weak predictor of number of alien plant species.
156

Sustainability of nature-based tourism

Törn, A. (Anne) 04 December 2007 (has links)
Abstract Nature-based tourism has increased considerably during recent years, which has raised questions about the tolerance of ecosystems experiencing growing visitor numbers. The present thesis focuses on the ecological and social sustainability of nature-based tourism in protected areas and their surroundings. The objective of the ecological studies was to determine the effects of tourism on vegetation, soils and risk of introduction of alien plant species. The social survey investigated whether opinions concerning nature conservation and tourism by local people are dependent on socio-economic and demographic factors. The studies were carried out in Oulanka and Pallas-Ounastunturi National Parks, and in the Ruka and Syöte regions, in northern Finland. This research demonstrated that nature-based tourism (hiking, horse-riding and skiing) affected boreal forests, altering vegetation, soils and trail networks. The major effects were; reduction in vegetation cover, including of different life-forms, changes in plant species composition, soil chemistry and soil erosion. Trampling decreased plant cover more on slopes compared to flat terrain. Moreover, downward trampling reduced the plant cover more than did upward trampling. In addition, horse riding resulted in the introduction and establishment of a range of alien plant species. In general, ecological changes due to nature-based tourism were inevitable even when there were limited numbers of visitors. Respondents to the survey were classified into three groups according to their opinions concerning nature conservation and tourism development: (i) supporters of nature conservation, (ii) critical to nature conservation and (iii) critical to tourism development. The majority of respondents were supporters of nature conservation. However, opinions were strongly dependent on the socio-demographic background of the respondents, such as residential area, age, level of education and indigenousness. Since the impacts of tourism were dependent on the characteristics of plants and habitats and the quality of activities, case-specific planning, monitoring and rapid responses are the most efficient methods in avoiding irreversible environmental damages. Furthermore, close co-operation between different stakeholders and detailed scientific information about the ecological, economic and social elements of sustainability are needed to promote a sustainable development of nature-based tourism.
157

Právní úprava ochrany rostlinstva a živočišstva / Legal regulation of the protection of plants and animals

Becková, Kateřina January 2011 (has links)
The subject of my thesis is the regulation of wild fauna and flora protection. Given that the planet's biodiversity is threatened and there is a significant decline of the number of wild flora and fauna species, I consider an adequate regulation in this area the precondition for slowing down or halting this decline and restoring the wild fauna and flora populations. I chose this topic with the aim to show how the legislation provides for the protection of wild fauna and flora species on different levels, and in order to show in how far the regulations are sufficient. Considering the significant negative impact of invasive alien fauna and flora species on native species and the whole ecosystem, I am focusing in every chapter on these invasive species with the aim of pointing out the shortcomings regarding the regulations in this area. The question of regulation of the protection of wild fauna and flora is examined from a general perspective, the perspective of international law, the perspective of European Union law, as well as from the perspective of Czech and French law, focusing on the sources of legislation, guidelines, organizations and subjects, tools and responsibilities. This thesis comprises six chapters. Chapter One is introductory and focuses on the loss of biodiversity and causes of this...
158

Impacts of the invasive reed Arundo donax on biodiversity at the community-ecosystem level

Guthrie, Gené January 2007 (has links)
Magister Scientiae - MSc (Biodiversity and Conservation Biology) / Arundo donax is an invasive species that mostly impacts on sensitive riparian ecosystems. Arundo is also invasive in South Africa, though less is known about its ecology, biology, and impacts. Since California and the Western Cape of South AFrica have similar Mediterranean-type climates, we could assume that the impacts of Arundo on ecosystems in California are likely to be similar in the Western Cape, and that control methods used could be extrapolated for use in South Africa. This thesis attempted to determine what impact Arundo has on biodiversity at the community-ecosystem level. / South Africa
159

Buitelandse laste en bates van Suid Afrika (Afrikaans)

Swart, Pieter Hendrik 03 January 2007 (has links)
No abstract available. / Dissertation (M Com (Economics))--University of Pretoria, 2007. / Economics / Unrestricted
160

Allelopathic interference potential of the alien invader plant Parthenium hysterophorus

Van der Laan, Michael 04 April 2007 (has links)
The alien invader plant Parthenium hysterophorus is a Category 1 weed in South Africa, where it poses a serious threat to indigenous vegetation in particular, and to biodiversity in general. In addition to its competitive ability, it is hypothesized that the successful invasiveness of P. hysterophorus is linked to the allelopathic potential of the plant. One compound in particular, parthenin, is alleged to play a major role in this allelopathic potential. Interference between P. hysterophorus and three indigenous grass species (Eragrostis curvula, Panicum maximum, Digitaria eriantha) was investigated on a site with a natural parthenium infestation at Skukuza, Kruger National Park. The trial was conducted over two growing seasons on exclosure plots which eliminated mammal herbivory. P. maximum displayed best overall performance and was eventually able to completely overwhelm P. hysterophorus. Eragrostis curvula and D. eriantha grew more favourably in the second season after becoming better established but were clearly not well adapted to the trial conditions. Although P. maximum was the supreme interferer, all grasses were able to significantly interfere with P. hysterophorus growth in the second season. The ability of P. maximum to interfere with P. hysterophorus growth so efficiently that it caused mortalities of the latter species, indicates that P. maximum exhibits high potential for use as an antagonistic species in an integrated control programme. An investigation on the production dynamics of parthenin in the leaves of P. hysterophorus indicated that high levels of this compound are produced and maintained in the plant up until senescence. The high resource allocation priority of the plant towards this secondary metabolite even in the final growth stages may indicate the use of residual allelopathy to inhibit or impede the recruitment of other species. Studies on the persistence of parthenin in soil revealed that parthenin is readily degraded in soil and that microbial degradation appears to play a predominant role. Significant differences between parthenin disappearance-time half-life (DT50) values were observed in soils incubated at different temperatures and in soils with different textures. Exposure of the three grass species to pure parthenin showed that, in terms of their early development, the order of sensitivity of the grasses was: Panicum maximum>Digitaria eriantha>Eragrostis curvula. It may therefore prove challenging to establish P. maximum from seed in P. hysterophorus stands during the execution of an integrated control programme due to the sensitivity of this grass species to parthenin. From the research findings it appears possible that P. hysterophorus can inhibit or impede the recruitment of indigenous vegetation under natural conditions. At least one mechanism through which this alien species can exert its negative influence on other plant species is the production and release of parthenin. / Dissertation (MSc (Agric) Agronomy)--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

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