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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.

Utilisation and dynamics of an arid savanna woodland in the Northern Province, South Africa

Rathogwa, Nkhweleleni Ronald 06 September 2023 (has links) (PDF)
This thesis reports upon the findings of a study into the socioeconomic and ecological drivers of plant resource utilisation, and dynamics of woody plants used by rural people in the Northern Province, South Africa. The key components were to (1) quantify the range of socioeconomic drivers of plant resource utilisation in rural communities, (2) identify plant species highly preferred by people and their uses, (3) quantify the impacts of plant resource harvesting, (4) seek relationships between spatial distribution patterns of plants and productivity, (5) determine the responses of trees to harvesting regimes, and (6) elucidate the impacts of selected management actions on plant resource supply and hence sustainability. Each of these was pursued through a combination of surveys and empirical experimentation. High unemployment rate, low educational levels, large family sizes and most importantly low overall family income are characteristic of this rural community. As a result, many people are still reliant on wild growing plants for their household and economic needs. The three main use categories associated with people in this rural village, in order of their importance, are: construction, food and energy. It is construction and energy uses that are associated with very few species. Harvesting of plant materials for these two use categories is destroying the preferred species in communal land. Two plant species, Colophospermum mopane and Androstachys johnsonii, are the most preferred plant species for construction and energy purposes. In a protected area the C. mopane population is stable, an indication that recruitment balances mortality. The same applies to A johnsonii. However, in communal land the size class frequency distribution of C. mopane varies at three distances from the village, suggesting that communal patterns of C. mopane utilisation are unfavourable to this species. This is probably so because of intense browsing within the village and high levels of harvesting. However, A johnsonii at two harvest zones in communal land show the same trend as in the protected area: the inverse J-shaped curve which is a characteristic feature of a stable population. Selective harvesting therefore, has little impact on recruitment of young A. johnsonii trees. Conflicting results were evident with respect to the role of competition in tree populations. Spatial distribution methods (i.e. nearest-neighbour analysis and departure from randomness approach) from a number of plots suggested that competition was not important at most plots. Yet, the strong negative relationship between loge mean stand basal area and log0 stand density indicated that competition is a significant factor affecting individual tree and stand woody productivity. Most plots from the communal land, when plotted on the same graph of plots from the protected site, lay far below the thinning line, suggesting that harvesting is promoting rapid growth of trees in communal land. The five species harvested responded differently from each other. Full and partial harvesting of C. mopane trees during December at ~30 cm above ground level resulted in 100% survival rate after one year. The equivalent diameter of coppice shoots was significantly positively related to stump size and light availability. The former suggests that harvesting bigger trees will result in rapid diameter growth of coppice shoots while the latter suggests that shoots are suppressed by shade from neighbouring trees. The equivalent shoot diameter was significantly negatively related to sum of neighbour size divided distance ratios, an indication of competition between neighbouring trees. All big trees and 70% of the small trees of A johnsonii species died when the same season, height of cutting and harvesting regime applied to C. mopane was used. Partial harvesting resulted in 60 and 45% survival rates for big and small trees respectively. Coppice shoot production of the surviving stems was also very low compared to C. mopane. A static transition model was developed to simulate requirements for sustainable harvesting of Colophospermum mopane woodlands. The model predicts that a combination of high levels of harvesting and browsing will result in the depletion of the resource base within three decades.

Control, conflict and change in the residential landscape

Morton, Nicholas James January 1997 (has links)
No description available.

Planning for biodiversity in the wider countryside : recognising opportunities, overcoming barriers

Watts, Kevin January 2001 (has links)
There is an increasing imperative to conserve the biological diversity of the world to ensure its future viability and integrity. The traditional approach in England has been to protect a series of small, isolated sites. Recent research has demonstrated the inadequacies of this approach, suggesting a need to direct energies more towards conservation in the surrounding wider countryside. However, there are considerable difficulties associated with achieving biodiversity objectives in the wider countryside, as there is a heavy reliance on non-statutory planning mechanisms. Whereas solutions to biodiversity conservation have generally been seen to lie in the realm of natural science, this thesis recognises the need for a better understanding of the people, policies and activities involved in the process. It therefore couples social science perspectives with an understanding of ecological science principles, in order to investigate the issues affecting the implementation of biodiversity conservation plans in three case studies in south west England. By employing a range of qualitative techniques this research: defines a number of conservation objectives for the study areas; uses conservation objectives as a basis for conducting a content analysis of biodiversity planning documents, in order to uncover potential implementation opportunities and barriers; presents the results in an analytical framework; explores and refines these through a series of semi-structured interviews with key biodiversity actors. This research uncovers a complex set of interacting issues. These issues relate to partnership styles of working, building agreement and trust, variable levels of knowledge about habitat and species in the wider countryside, restoration techniques, indicative strategies, strategic targeting of resources, financial support to farmers and other land managers, the role of monitoring, and policy responses to recent agricultural crises. The results attest to the importance of a social-scientific understanding of biodiversity planning, in particular, of the forces which drive or obstruct the implementation of local solutions. The thesis concludes with a number of recommendations, based on original evidence, aimed at improving the implementation of biodiversity plans in the wider countryside.

Presentation Of Classical Archaeological Sites In Virtual Environment Case Studt: Sagalassos

Basagac, Ozge 01 July 2005 (has links) (PDF)
ABSTRACT PRESENTATION OF CLASSICAL ARCHAEOLOGICAL SITES IN VIRTUAL ENVIRONMENT CASE STUDY: SAGALASSOS BASAgA&Ccedil / , &Ouml / zge M.S, Department of Architecture in Restoration Supervisor: Dr. Fuat G&Ouml / K&Ccedil / E July 2005, 123 pages Parallel to the growing concern for the protection and presentation of archaeological sites, virtual environments (VE) are in use for visualization purposes since mid 1980&rsquo / s. This thesis investigates the potentials and problems of presenting a classical archaeological site in VE from the viewpoint of conservation science, to ensure the welfare of the remains. The study is handled in two sections as a conceptual part and a case study. The conceptual part, first dwells upon the history, aim and techniques of the VE presentations. This section ends with the development of criteria for the evaluation of VE presentations of classical archaeological sites. For the case study, the antique city of Sagalassos is investigated through its history, urban tissue, architecture, multidisciplinary studies and VE projects. The thesis concludes with general remarks on the presentation of classical archaeological sites in VE and proposes some solutions to improve the presentation of Sagalassos in particular.

Preservação Ambiental e Publicidade: uma relação possível

Santos, Lana Cristina Nascimento 23 May 2007 (has links)
Made available in DSpace on 2016-08-03T12:30:35Z (GMT). No. of bitstreams: 1 capa e folha de rosto.pdf: 7886 bytes, checksum: 2e38862567ae2dbff0a329670c9754cb (MD5) Previous issue date: 2007-05-23 / The environmental issue and its proper preservation constitute a matter of global concern that is gaining momentum lately. The main objective of this paperwork is to show that suitable developed advertisement campaigns can change the behavior of consumers in order to produce environmental responsible attitudes, even within a capitalist and consumerist order. The work shows an analysis of mass media samples conveniently selected, based on a deep research on printed and electronic media. The recollection of professional opinions (survey researches) contributes to the analytical approach, working with communication concepts, interaction, language, culture and representations to try to capture the possible relationships between environmental preservation and marketing campaigns. The work gathers some final suggestions and considerations that are not supposed to be definite. However, this set of comments can be of good value when it comes to the creation of social consequent and environmental responsible advertisement campaigns, being a subject of interest to the advertisement activities, private companies and governmental professionals as well to independent organizations.(AU) / A questão ambiental e sua preservação é assunto de interesse global, impulsionado por todos os setores. Com o objetivo principal de mostrar que, mesmo inseridas em uma lógica empresarial, peças publicitárias bem elaboradas podem modificar comportamentos para que se efetive a preservação ambiental, o trabalho apresenta a análise do corpus selecionado por conveniência, a partir de amplo levantamento junto aos diversos formatos de anúncios veiculados na mídia impressa e eletrônica. O levantamento de opiniões, assim como pesquisas do tipo survey, contribuiu com a abordagem analítica que trabalhou com conceitos de comunicação, interação, linguagem, cultura e representações para compreender, a possibilidade da relação da preservação ambiental com a publicidade. O trabalho agregou sugestões apresentadas nas considerações que não se pretendem finais, mas que poderão contribuir para profissionais da atividade publicitária, empresas, governos, e organizações da sociedade civil no tocante à responsabilidade socioambiental de suas comunicações.(AU)

Effects of environmental change on plant performance and plant-herbivore interactions

Prill, Nadine January 2014 (has links)
Global environmental change fundamentally affects plants and their interactions with other species, and this has profound impacts on communities and ultimately ecosystems. In order to understand the mechanisms involved, we need to elaborate on the combined effects of different global change drivers on multiple levels of plant organization, including the biochemical level (production of defence compounds), the whole organism, the population, and the plant-herbivore interaction level. This thesis investigates (1) the combined effects of factors related to climate change and habitat fragmentation on Brassica nigra and (2) the effects of Zn soil pollution on the heavy metal hyperaccumulator Noccaea caerulescens at these different levels. Common garden and greenhouse experiments with B. nigra applied drought stress and elevated CO<sub>2</sub> to examine climate change impacts, while crossing treatments (inbreeding and between-population outbreeding) were used to investigate habitat fragmentation effects. Heterosis was lost under drought stress, and there were several interactive effects of the experimental treatments that varied within and among populations. In a greenhouse experiment with N. caerulescens, plants were grown on soil with different amounts of zinc. Plants had greater herbivore resistance when grown on Zn-amended soil, and invested more in herbivore tolerance when grown on soil without added Zn. In general, the results indicate that factors related to global environmental change have complex and interactive effects on different levels of plant organization. The findings are discussed in terms of their implications for ecology, evolution and conservation.

The value of agri-environment schemes and farm woodland for bats and nocturnal insects

Fuentes-Montemayor, Elisa January 2011 (has links)
Many bat species in Europe have undergone severe population declines during the last century and one of the driving causes is believed to be the loss of roosting and foraging habitat through agricultural expansion and intensification. Modern agricultural practices have also had strong negative effects on many insect groups, such as moths, which are important components of the diets of many bat species. Agri-environment schemes (AES) have been introduced in many countries as an attempt to counteract the negative effects of intensive agriculture on biodiversity by providing financial incentives for farmers to adopt environmentally-sensitive agricultural practices. AES are potentially beneficial to bats and nocturnal insects, but the response of these taxa to their implementation had not been assessed prior to this study. Here, the potential benefits (or otherwise) that bats and their insect prey species gain from the implementation of certain AES management prescriptions was assessed using ultrasonic detectors (to assess bat activity levels) and heath light traps (to quantify nocturnal insect abundance) at 18 pairs of AES and conventionally-managed farms. In addition, the influence of the surrounding landscape on bats and insects was quantified to evaluate the relevance of a landscape-scale management approach for the conservation of these taxa. Some of the AES prescriptions assessed in this study benefited moths (and are potentially beneficial for moth-eating bats), but not Pipistrelle bats nor their insect prey. The most important factors associated with bat activity on farmland were metrics related to woodland configuration in the surrounding landscape, which suggests that conservation efforts for bats should focus on the creation and management of this habitat. Currently, some AES prescriptions aim to increase the amount and quality of woodland on agricultural land, but little is known about how woodland character relates to bat abundance and insect prey availability; therefore, recommendations for woodland creation and management rarely consider the requirements of foraging bats. Here, the influence of woodland character (e.g. vegetation structure and patch configuration) on bats and nocturnal insects was assessed. Vegetation surveys were conducted and Geographic Information Systems (GIS) were used to quantify the vegetation character and spatial configuration of 34 woodland patches within farmland. Two complementary methods (acoustic monitoring and bat trapping assisted by an acoustic lure) were used to assess the influence of woodland vegetation character, patch configuration and the surrounding landscape on bat populations. Nocturnal insect abundance at each site was assessed using heath light traps. Data presented here demonstrate that bats show species-specific associations with woodland vegetation structure and patch configuration; patterns of higher bat abundance and activity at small and isolated woodland patches suggest that bats utilize this habitat more intensively in landscapes where woodland is scarce. This thesis also shows that moths are strongly influenced by woodland character; in general, large woodland patches of compact shapes, composed of a large number of native tree species and a dense understory cover, and located close to other woodlands were associated with high moth abundance and species richness (and are potentially valuable for moth-eating bats). Other nocturnal insects (mainly Diptera) were not influenced by woodland character. This study also shows that bats and nocturnal insects are influenced by the landscape context; moths are mainly influenced by the extent of semi-natural environment (such as rough grassland and scrub) within small spatial scales (within 250 m; although effects of woodland extent were detected at larger spatial scales for woodland specialists moths). Bats are mainly influenced by woodland-related landscape metrics. Some bat species are influenced by the surrounding landscape at large spatial scales (within 3 km) and would benefit from woodland creation and management at a wide-landscape-scale. The findings presented in this thesis have important management implications for the design of agri-environment schemes. A list of management recommendations to optimize the benefits that bats and nocturnal insects gain from these schemes is presented in the final section.

The wilderness knot

Washington, Haydn G., January 2006 (has links)
Thesis submitted for the degree of Doctor of Philosophy University of Western Sydney. / Title from electronic document (viewed 2/6/10) Interviews held with: "James' Dharug, Traditional Custodian; Dr. Rob Lesslie, conservation biologist, Dr. Val Plumwood, environmental philosopher, Virginia Young, Director WildCountry Project, Professor Mike Archer, Dr. Deborah Bird Rose, anthropologist, Ms. Penny Figgis, former Vice President of ACF, Dr. Tim Flannery, Director South Australian Museum, Mr. Dean Stewart, Aboriginal Education Officer, Melbourne Botanic Gardens, Dr. Rosemary Hill, ACF Northern Lands Project Officer, Professor Harry Recher.

Deep anthropogenic topsoils in Scotland : a geoarchaeological and historical investigation into distribution, character and conservation under modern land cover

McKenzie, Joanne T. January 2006 (has links)
Deep anthropogenic topsoils – those augmented through long-term additions of mineral bulk among fertilising agents – retain in both their physical and chemical make-up significant indicators for cultural activity. This project researched the geographical distribution and historical context of deep anthropogenic topsoils in Scotland and the Isles, and used this information to investigate the impact of current land cover upon the cultural information they retain. In so doing, the project investigated the potential for conservation of this significant cultural resource. A review of the historical information available on agricultural and manuring practices for Scotland identified several factors likely to affect deep topsoil distribution and frequency. These were: the availability of bulk manures to Scottish farmers, the significance of the seaweed resource in determining fertiliser strategies in coastal areas, and the influence of urban settlement and associated patterns of domestic and industrial waste disposal on the location of deep topsoils. Evidence for widespread deep topsoil development was limited. The primary data source used – the First Statistical Account of Scotland – was manipulated into a spatial database in ArcView GIS, to which geographical data from the Soil Survey of Scotland and national archaeological survey databases were added. This was used to devise a survey programme aiming both to investigate the potential factors affecting soil development listed above, and to locate deep topsoil sites for analysis. Three sites were identified with deep topsoils under different cover types (woodland, arable and pasture). The urban-influenced context of two of these highlighted the significance of urban settlement to the location of Scottish deep topsoils. Analysis of pH, organic matter, and total phosphorus content showed a correlation between raised organic matter and a corresponding increase in phosphorus content in soils under permanent vegetation. By contrast, soils under arable cultivation showed no such rise. This was attributed to the action of cropping in removing modern organic inputs prior to down-profile cycling. The potential for pasture and woodland cover to affect relict soil signatures was therefore observed. Thin section analysis aimed to both provide micromorphological characterisation of the three deep topsoil sites and investigate the effect of modern land cover on micromorphological indicators. Distinctive differences in micromorphological character were observed between the rural and urban deep topsoils, with the latter showing a strong focus on carbonised fuel residues and industrial wastes. All sites showed a highly individual micromorphological character, reflective of localised fertilising systems. There was no correlation between land cover type and survival of material indictors for anthropogenic activity, with soil cultural indicators surviving well, particularly those characteristic of urban-influenced topsoils. Suggestions for preservation strategies for this potentially rare and highly localised cultural resource included the incorporation of deep anthropogenic topsoil conservation into current government policy relating to care of the rural historic environment, and the improvement of data on the resource through ongoing survey and excavation.

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