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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.
31

Is biodiversity really a barrier to ecosystem invasion? an analysis of community- and ecosystem-based mechanisms of plant invasions /

Jones, Rachel O. January 2009 (has links)
Thesis (M.S.)--Villanova University, 2009. / Biology Dept. Includes bibliographical references.
32

Testing the water: How communities value, use, impact and manage water-related ecosystem services originating in an urban protected area

Brill, Gregg January 2017 (has links)
Freshwater ecosystems and their associated landscape features found in developing cities and urban protected areas are essential components of urban social-ecological systems providing city residents with cultural, provisioning and regulating services, all of which hold value. Understanding these values requires overcoming conceptual and methodological challenges so that the multi-dimensional nature, relating to the varying values, benefits, and trade-offs are understood. Understanding values, benefits and trade-offs is essential for ensuring informed and effective management of these services and the landscapes that provide them. This requires the development of tools and methods to predict how changes in land-use and management practices might affect the provision of such services. This study contributes to both the methodological and empirical literature by developing integrated and multidisciplinary approaches to assessing the beneficiaries of freshwater ecosystem services in an urban context and recognising the ecological, social and economic values assigned to ecosystem services over multiple spatial and temporal scales. The aim of this thesis was to assess how beneficiaries, stakeholders and managers within a developing city context, recognise, value and manage the multiple diverse ecosystems services associated with freshwater ecosystems as provided by different landscape features originating in an urban protected area. This aim was achieved by establishing who the beneficiaries of freshwater ecosystem services are, uncovering the spatial and temporal relationships these beneficiaries have with landscape features, determining the nature of ecosystem service values, benefits, impacts and trade-offs as experienced by the different users, as well as analysing the management policies and practices associated with urban ES. Drawing on accumulated as well as existing data sets, newly developed methods and approaches were implemented in this study. This work was primarily undertaken in Table Mountain National Park and in Cape Town, South Africa. A comparative analysis of the perceptions of park managers toward ecosystem service governance and management was undertaken in Table Mountain National Park and in Tijuca National Park, in Rio de Janeiro, Brazil. Natural freshwater ecosystems (e.g. rivers), particularly when combined with built infrastructure (e.g. dams), provide highly valued features in landscapes, delivering multiple cultural services to city residents. Recreation, aesthetic and existence services were valued highest by respondents. People who live closer to the park use, and benefit from, the park's freshwater ecosystems more frequently than those living further away. Park visitors want ease of access in terms of distance to specific freshwater ecosystems, and then once there they want a diversity of activity options, such as recreation opportunities as well as places to reflect and meditate. The outcomes of the cultural-service study in this thesis have important management implications where insights gained can guide management to ensure equitable and sustainable ecosystem service provision to all city residents. To enhance the management of ecosystem services in urban protected areas, it is important to understand the level of inclusion of the ecosystem-service concept in park policy and daily practice. Although management perceptions correspond well with park policy, the concept of ecosystem services is still narrowly developed and needs to be better integrated into the management structures and activities of Table Mountain National Park and Tijuca National Park. Outcomes from this study show that management attention relating to fresh water is still primarily focussed on biodiversity conservation and maintaining system processes and functions. Implementing and enacting the ecosystem services concept largely still needs to happen within parks and urban interfaces. The lack of communication between managers and stakeholders of protected areas makes identifying the beneficiaries of fresh water and valuing ecosystem services difficult, especially when water and associated services flow outside of the park boundaries. An important component of this study was to determine the changes to ecosystem service provision as fresh water flows from a protected area into and across an urban landscape. A scoring system was developed to determine whether changes in land use along three case-study rivers in Cape Town, all of which originate in Table Mountain National Park, positively or negatively impact the provision of water-related ecosystem services. Changes in service provision, over time, were compared to changes in long-term water quality data to verify results from the scoring system. Generally, service levels increased over time along the upper river reaches, whereas the middle and lower reaches of the rivers showed overall declines. The changes to service provision influence the value that urban residents assign to rivers. Findings in this study suggest that the provision of cultural ecosystem services as well as the protection of biological diversity were the key factors considered by those living along the case study rivers as reasons for being willing to pay to protect rivers. Provisioning services were shown to be of less value, as were the economic contribution to property values based on river frontage. This study supports the call for more innovative research to be undertaken in developing countries to break new ground and provide more comprehensive analyses to further our understanding of the values of urban ES. The challenge for environmental researchers in this context is to intensify efforts to understand the relationships between specific landscape elements and freshwater ecosystems and human perceptions, feelings and interpretations, and to express these relationships in ways that are useful for environmental policy and management.
33

Sowing the Seeds of Entrepreneurial Influence : A Study of Network Mobilization Within the Technology Ecosystem in Kenya

Schmoll, Tamara, Östberg, Lisa January 2022 (has links)
Background: Previous research has shown that entrepreneurship can foster regional development in countries as Kenya, that struggle with unemployment and a stagnating GDP. However, the topic of entrepreneurial ecosystems in Kenya, its configuration of actors, and the networks between them is insufficiently studied. Thus, exploring the conditions of the ecosystem within the technology sector and investigating how both female and male entrepreneurs can mobilize their networks to survive and thrive adds novelty to entrepreneurship research. Purpose: The purpose of this paper is to understand what affects the success and failure of entrepreneurs in the Kenyan technology ecosystem. Furthermore, this paper aims to explore how entrepreneurs can mobilize their network to survive and thrive and therefore adds to research on the topic of network mobilization. Method: The chosen method for this qualitative study is a case-study approach, enabling a holistic case study on the conditions of the technology ecosystem and nested case studies to understand network mobilization efforts. Twelve semi-structured interviews were conducted with both entrepreneurs as well as actors of the ecosystem. A thematic analysis was utilized to analyse the findings of the ecosystem followed by a comparative analysis that allowed us to identify similarities and differences between female and male entrepreneurs and their approach to utilize networks.  Conclusion: This study extends the existing research on entrepreneurial ecosystems by identifying enablers and obstacles in the Kenyan technology ecosystem. Especially community and kinship support were identified as an enabler for resources that the government or financial institutions fail to provide. Furthermore, the paper extends knowledge on network mobilization, with emphasis on a comparison between male and female entrepreneurs.
34

PERCEPTIONS AND KNOWLEDGE OF A SELECTED GROUP OF ORGANIC CONSUMERS IN BLOEMFONTEIN, FREE STATE PROVINCE

Hurndall, L, Wolmarans, J.L., Hattingh, Z January 2014 (has links)
Published Article / Organic agriculture is a production method that upholds the well-being of soil, ecosystems and people. It relies on ecological processes, biodiversity and cycles tailored to local conditions. This descriptive study assessed the knowledge and perceptions of organic food consumers in Bloemfontein. A convenience sample of 60 consumers (male and female) was selected to participate in the study. A structured questionnaire was designed to obtain data at a local fresh-produce grocer. Most of the consumers showed positive and negative attitudes towards organic products. Most consumers had basic knowledge regarding organic products, but it also became evident that there was uncertainty surrounding facts of organic products, such as labelling standards. Only 12% of respondents interpreted the term “organic” correctly. Human health (86.67%) and environmental concerns (28.33%) were the key factors influencing consumer preference for organic food. Organic fruit and vegetables (45.37%) were the most popular purchased organic items amongst consumers. The majority of consumers (61.67%) stated that organic products are affordable. The results of the present study provided valuable insight into the knowledge, perceptions and attitudes of consumers towards organically grown foods. The general positive attitude of consumers can be attributed to consumers' basic knowledge of, and preference for, organic food. Despite the organic lifestyle being in the minority in this region, there continues to be a growing demand for organic products in Bloemfontein, and for this reason producers have ensured a continued supply of organic products.
35

The palaeoecology of a South African Early Permian, and a Late Permian Australian, Gondwana coal

Glasspool, Ian James January 2000 (has links)
No description available.
36

The physiological ecology of photosynthetic ciliated protozoa and their trophic roles in freshwater and brackish planktonic microbial food webs

Perriss, Stephen James January 1993 (has links)
No description available.
37

Effects of enriched atmospheric concentration of carbon dioxide on tree litter decomposition

Cotrufo, Maria Francesca January 1994 (has links)
No description available.
38

Rhizobium leguminosarum biovar viciae populations from arable and grass lands

Palmer, Katharine M. January 2000 (has links)
No description available.
39

Stream mesocosms in ecological risk assessment : experimental, analytical and ecological considerations

Whittle, Don January 2000 (has links)
No description available.
40

The ecology of freshwater amphipods : a study of invasive and native species

MacNeil, Calum January 1997 (has links)
No description available.

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