No description available.

Large catfishes (Clarias gariepinus & Clarias ngamensis) are not exploited commercially in the Okavango Delta, Botswana. They however constitute a large proportion of the gill net fishery catch (23 %) albeit as by-catch, coming second after cichlids (70 %). Monthly experimetal gill net sampling over 8 years showed that C. gariepinus was the most abundant species in the Okavango Delta by mass making up 37 % of the catch composition by fresh weight. Despite the relatively high abundance of C. gariepinus in the Okavango Delta, its status has never been fully assessed. For this reason, this study aimed to assess the status of C. gariepinus in the Okavango Delta with the particular goal to determine if the species could support a directed commercial gill net fishery. Investigation of the effects of the flood pulse on abundance of C. gariepinus showed that variability in water levels was the major driver of population abundance for this species. Three biological variables: (1) catch per unit effort (CPUE); (2) % catch composition and (3) Shannon's diversity index (H') exhibited a negative and significant relationship with the flood index within a year. The variation in these variables was statistically significant between months. There was a weak positive relationship between water levels and the biological variables between years suggesting increase in productivity of the system at high water levels without a lag period. Age and growth were determined using sectioned otoliths. Edge analysis showed that growth zone deposition occurred during the drawdown period in summer when water temperature and day length were increasing. The maximum recorded age was 15 years. Growth of this species was best described by the linear models (y = 21.50x + 427.39 mm LT; r² = 0.35) for females and (y = 23.79x + 440.83 mm LT; r² = 0.38) for males. The von Bertalanffy growth model described growth as Lt = 10000(1- exp(-0.002(t + 18.07))) mm LT for combined sexes Lt = 10000(1- exp( -0.002(t + 18.50))) mm LT , for females and Lt =908(1-exp(-0.076(t+7.95)))mmLT for males. Age at 50 % maturity was attained in the first year of life. Spawning occurred throughout the year with an apparent peak between November and April. The mean total annual mortality rate (Z) was 0.25 per year. The mean annual natural mortality rate (M) was 0.20 per year and fishing mortality (F) was calculated at 0.05 per year. The life history strategy of C. gariepinus was in between the periodic and opportunistic strategies. Therefore management of this species should be aimed at maintaining a healthy adult population and age structure. Since a large portion of the Okavango Delta is already protected and most other parts are also inaccessible to fishers there are enough spatial refugia for the species and the status quo should be maintained. Under this scenario, there is no need for regulation of the current mesh sizes because the species is harvested after maturity and replenishment of exploited populations will always occur from other parts of the system. Per recruit analyses indicate that the current fishing mortality maintains spawner biomass at levels greater than 90 % of pristine levels. Therefore a commercial fishery may be established using mesh 93 mm to maximize yield with a rotational harvesting strategy. Close monitoring is essential to ensure that re-colonization of overexploited habitats does indeed occur. Recreational angling and commercial gill net fishing need to be separated on a spatial and temporal scale during the feeding run to minimize potential conflicts.

This thesis examines the role of environmental non-government organizations in relation to the role and responsibility of government for wetland conservation in British Columbia. The role of a small community-based environmental organization called the Burns Bog Conservation Society in decisions about Burns Bog, a large privately-owned wetland located in the Lower Mainland, is analyzed. Drawing from a broad range of literature on environmentalism and conservation, the thesis begins with an historical account of the environmental movement, giving a broad view of environmental conservation and the role of environmental organizations. A typology of roles and analytical framework is subsequently derived from a study of environmental non-government organizations involved in managing water resources in British Columbia's Fraser River Basin. Three main roles, advocacy, supplemental and transformative, are discussed as they relate to activities prior to and during the Burns Bog Analysis, a provincially established land use study of Burns Bog. This research found that a small community-based environmental organization, through advocacy, can ensure that ecological integrity is not neglected as a result of poor planning and decision-making. The case study demonstrates that a small environmental organization can pressure governments to broaden their view of land-use and environmental issues, assuring more informed decision-making. An environmental organization can also supplement the regular roles and responsibilities of government, first by supplying a service that government is unable or unwilling to provide, and second by participating in and legitimizing consensus-based decision-making processes. The case study demonstrates how a small environmental organization can provide and review information and participate in creating options and solutions in land-use decisions. Finally, an environmental organization can influence, overtime, the fundamental restructuring of government planning and decision-making processes and transform the way society thinks and operates. The thesis concludes that environmental non-government organizations have an important role to play in ensuring the recognition and conservation of British Columbia's wetlands in government planning and decision-making processes; in informing and educating government and the public about ecological systems and their values; and in counter-balancing strong economic, political and development interests. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

The development of market socialism in China has contributed to a spatial economic transformation characterized, among other things, by the apparent capacity to rapidly industrialize without transferring large numbers of people into big cities. The most striking element of this transformation has been the phenomenal growth and spatial proliferation of industries in particular areas of the Chinese countryside. The conventional wisdom of existing theories of development, industrialization, and urbanization does not adequately explain the emergence of these relatively productive regions. This thesis examines the key patterns and underlying processes and mechanisms which must be accommodated in a new analytical and conceptual framework for understanding rural transformation and the wider spatial economic restructuring in China's lower Yangzi delta. The overall objective is to explore the theoretical implications of the local character of regional change through an evaluation of a hypothetical model of mega-urbanization. The model situates the emergence and specific patterns of industrial production within a complex network of interactions and interrelationships embedded in overlapping administrative and institutional structures which are themselves largely tied to the circumstances of particular places. The resulting investigations are based upon an analysis of regional and local level statistical and other documentary sources, numerous interviews, field observations, and a survey questionnaire of rural enterprises which was part of a detailed case study of one county level area in the lower Yangzi delta. Two central findings are revealed. First, the patterns and underlying processes and mechanisms of regional development in the delta are fundamentally linked to intensely localized exigencies and opportunities within the wider Chinese space economy. Second, external economies, the dynamics of agglomeration, and the role of large cities and other exogenous forces, while significant, were less important in the delta than were endogenous forces. The details of these findings are incorporated into a revised model of mega-urbanization which highlights the critical processes and mechanisms which underlie the patterns observed, what establishes these processes and mechanisms, and what stabilizes and reproduces them. The thesis concludes by suggesting an agenda for the creation of appropriate planning and management responses for the lower Yangzi delta region. / Arts, Faculty of / Geography, Department of / Graduate

Meyer’s Parrot Poicephalus meyeri is the smallest of the nine Poicephalus parrots, forming the P. meyeri superspecies complex with five congeners. Their distributional range far exceeds any other African parrot, extending throughout subtropical Africa. Meyer’s Parrots had previously not been studied in the wild, and therefore, gathering high-quality empirical data on their behavioural ecology became a research and conservation priority. The primary aim of the study was to correlate environmental (e.g. rainfall, habitat availability, resource characteristics, food resource abundance and temperature) and social (e.g. inter- and intra-specific competition, predation, and human disturbance) variables with aspects of their ecology (e.g. flight activity, food item preferences, breeding activity, and group dynamics) to evaluate the degree of specialization in resource use (e.g. trophic, nesting and habitat niche metrics). African deforestation rates are the highest in the world, resulting in twelve out of the eighteen Meyer’s Parrot range states undergoing drastic loss of forest cover over the last 25 years. Most commentary on the population status of Meyer’s Parrots and other Poicephalus parrots pre-dates this period of rapid deforestation In addition, over 75 000 wild-caught Meyer’s Parrots and almost 1 million wild-caught Poicephalus parrots have been recorded in international trade since 1975. Empirical data from this study was used to identify ecological weaknesses (e.g. niche specialization or low breeding turnover) for evaluation within the context of deforestation in the African subtropics. Baseline data on the breeding biology and nest cavity requirements of Meyer’s Parrots was also necessary to assess the viability of applying the conservative sustained-harvest model to African parrots. A unifying goal of this study was to advance our knowledge of the ecology of African parrots and other Psittaciformes by assessing the validity of current hypotheses put forward in the literature. The Meyer’s Parrot Project was initiated in January 2004 on Vundumtiki Island in the north-eastern part of the Okavango Delta, Botswana. Due to high flood waters between March and July 2004, road transects were postponed till August 2004. Transects were conducted at Vundumtiki from August 2004 to July 2005 and February 2007 to August 2007, and at Mombo from August 2005 to January 2006. During 480 road transects over 24 months, food item preferences closely tracked fruiting and flowering phenology, resulting in significant positive correlations between Levins’ niche breadth, rainfall and food resource availability. Meyer’s Parrot can, therefore, be considered opportunistic generalists predispersal seed predator that tracks resource availability across a wide suite of potential food items, including 71 different food items from 37 tree species in 16 families. Meyer’s Parrots were, however, found to be habitat specialists preferring established galleries of riverine forest and associated Acacia-Combretum marginal woodland. These strong habitat associations facilitate their wide distribution throughout the Kavango Basin, Linyanti Swamps, down the Zambezi valley, up along the Rift Valley system in associations with the great lakes, through the Upper Nile and the Sudd, and west as far as Lake Chad through the Sahel. Seventy-five nest cavities were measured during this study, including 28 nest cavities utilized by Meyer’s Parrots within the 430ha sample area at Vundumtiki. Over 1700 hours of intensive nest observations at six nest cavities was undertaken. Meyer’s Parrots formed socially monogamous pair-bonds maintained over at least four breeding seasons. Breeding pairs established breeding territories up to an estimated 160ha within which there were 1–6 nest cavities. Eggs hatched asynchronously, yet nestlings fledged synchronously with similar body size and condition. There was evidence to support the incidence of extra-pair copulations, however, mitochondrial DNA sequence data are required to confirm the incidence of extra-pair fertilizations. Meyer’s Parrots had no preferences in regard to nest tree species beyond the incidence of suitable nest cavities, which are selected and further excavated to accommodate their non-random nest cavity preferences. There was a significant non-nesting Meyer’s Parrot population during the breeding season, likely due to this longlived cavity-nester delaying nesting until a suitable breeding territory becomes available. Meyer’s Parrots utilize communal roosts during summer and disperse from them according to the Foraging Dispersal Hypothesis. Due to the requirement to roost during the middle of the day to avoid heat stress, Meyer’s Parrots have bimodal flight and feeding activity patterns. The highest probability of locating Meyer’s Parrots is between 08h30 and 11h00 during summer when both adults are feeding on the seeds of fleshy-fruits in riverine forest communities. Due to the paucity of data on the current distribution and population status of Meyer’s Parrots and other African parrots, a continent-wide survey of all African parrots represents a conservation priority. Current deforestation rates in several Meyer’s Parrot range, their specialist habitat associations, and lack of evidence to support adaptability to a changing landscape mosaic necessitate the re-classification of Meyer’s Parrots as data deficient or nearthreatened. Based on low breeding population due to limited breeding opportunities, the CITES Appendix II wild-caught bird trade should also be halted until the sustainability of this trade has been evaluated and the relevant information made available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

This thesis presents an evaluation of the dispersive solid-phase extraction (d-SPE) method referred to as the quick, easy, cheap, effective, rugged and safe (QuEChERS) method for the determination of four organochlorine pesticide residues in fish samples. The pesticides investigated in this study were o, p′-DDT, p, p′-DDE, aldrin and dieldrin. The combined use of Gas Chromatography with an Electron Capture Detector (GC-ECD) and sensitive Time of Flight (TOF) mass detector facilitated the identification of the target analytes. In the absence of certified reference material, the overall analytical procedure was validated by systematic recovery experiments on spiked samples at three levels of 2, 5 and 10 ng/g. The targeted compounds were successfully extracted and their recovery ranged from 76 to 96% with relative standard deviations of less than 13%. The optimum QuEChERS conditions were 2g of fish powder, 10 ml acetonitrile and 1 min shaking time. The optimal conditions were applied to assess the levels of chlorinated pesticides in blunt-tooth catfish (Clarias ngamensis), tigerfish (Hydrocynus vittatus), Oreochromis andersonii and red-breasted tilapia (Tilapia rendalli) from the Okavango Delta, Botswana. Dieldrin, p, p′-DDE and aldrin were detected in all the analysed samples with a concentration range of 0.04 – 0.29, 0.07 – 0.33, 0.04 – 0.28 and 0.03 – 0.24 ng/g per dry weight in O. andersonii, C. ngamensis, T. rendalli and H. vittatus respectively. These concentrations were below the US-EPA 0.1 μg/g allowable limit in edible fish and the Australian Maximum Residue Limit (MRL) of 50 - 1000 ng/g in fresh fish. DDT was not detected in all the fish species investigated. The mean lipid content recorded in the fish samples were 1.24, 2.16, 2.18 and 4.21% for H. vittatus, T. rendalli, O. andersonni and C. ngamensis respectively. No systematic trend was observed between fish age and pesticide levels in fish. Acetylcholinesterase (AChE) activity assays were performed to assess the effects of organochlorine pesticides in Clarias ngamensis. The enzyme activity recorded in Clarias ngamensis from the Okavango Delta and the reference site was 12.31 μmol of acetylcholine iodide hydrolysed/min/g brain tissue. The enzyme activity remained the same indicating no enzyme inhibition. The conclusions drawn from this study are that the QuEChERS method is applicable for the determination of organochlorine pesticide residues in fish matrices. The fish from the Okavango Delta are safe for human consumption.

by Chan, Cheung-Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 184-189). / ACKNOWLEDGMENTS --- p.ii / LIST OF ILLUSTRATIONS --- p.iii / LIST OF TABLES --- p.iv / Chapter Chapter One --- Introduction --- p.1 / Chapter 1.1 --- Introduction / Chapter 1.2 --- Background / Chapter 1.3 --- Objectives of this study / Chapter 1.4 --- The Structure of the thesis / Chapter Chapter Two --- Literature Review --- p.9 / Chapter 2.1 --- Introduction / Chapter 2.2 --- Rural-urban fringe / Chapter 2.3 --- Characteristics of land use changes in the fringes / Chapter 2.4 --- Factors affecting the mechanism of land use changes in the urban fringe / Chapter 2.5 --- Parties involved in land use change decision / Chapter 2.6 --- Land use in the urban fringe of Zhujiang Delta / Chapter 2.6.1 --- Cities' in China / Chapter 2.6.2 --- Urban fringes in China ---the case of Zhujiang Delta / Chapter 2.6.3 --- Land use pattern in the Zhujiang Delta / Chapter Chapter Three --- Methodology --- p.29 / Chapter 3.1 --- Introduction --- Change detection techniques of land use changes / Chapter 3.1.1 --- A concept of change detection / Chapter 3.1.2 --- Change detection techniques / Chapter 3.2 --- Method employed to detect land use change in Zhujiang Delta / Chapter 3.3 --- Procedures / Chapter 3.3.1 --- Data description / Chapter 3.3.2 --- Preprocessing / Chapter a. --- Atmospheric correction / Chapter b. --- Image Registration / Chapter i. --- Spatial interpolation / Chapter ii. --- Intensity interpolation / Chapter 3.3.3 --- Image differencing / Chapter 3.3.4 --- Post-classification comparison / Chapter a. --- Land Use / Land Cover classification scheme / Chapter b. --- Definitions and image characteristics of land / Land cover classes / Chapter c. --- Supervised classification / Chapter d. --- Training sites / Chapter e. --- Maximum likelihood classifier / Chapter f. --- Accuracy assessment / Chapter g. --- post-classification comparison / Chapter Chapter Four --- Study Area --- p.64 / Chapter 4.1 --- Physical and agricultural landscape of Zhujiang Delta ---a general description / Chapter 4.1.1 --- Physical landscape / Chapter 4.1.2 --- Urban develoment / Chapter 4.1.3 --- Agricultural landscape / Chapter 4.2 --- Shunde / Chapter 4.2.1 --- Agricultural land use / Chapter 4.2.2 --- The image of Shunde / Chapter 4.3 --- Dongguan / Chapter 4.3.1 --- Agricultural land use / Chapter 4.3.2 --- The image of Dongguan / Chapter 4.4 --- Guangzhou / Chapter 4.4.1 --- Agricultural land use / Chapter 4.4.2 --- The image of Guangzhou / Chapter 4.5 --- Land use changes expected within the study area / Chapter Chapter Five --- Results and discussions --- p.83 / Chapter 5.1 --- Image differencing / Chapter 5.2 --- Results of classifications / Chapter 5.2.1 --- Shunde / Chapter 5.2.2 --- Dongguan / Chapter 5.2.3 --- Guangzhou / Chapter 5.3 --- Post-classification comparison change detection / Chapter Chapter Six --- Land use chancre analysis of the urban fringesin Zhujiang Delta --- p.107 / Chapter 6.1 --- Framework for discussion / Chapter 6 .2 --- Land use / land cover changes in Shunde / Chapter 6.2.1 --- Rural-to-urban changes / Chapter 6.2.2 --- Rural-to-rural changes / Chapter 6. 3 --- Land use / land cover changes in Dongguan / Chapter 6.3.1 --- Rural-to-urban changes / Chapter 6.3.2 --- Rural-to-rural changes / Chapter 6.4 --- Land use / land cover change in Guangzhou / Chapter 6.4.1 --- Rural-to-urban changes / Chapter 6.4.2 --- Rural-to-rural changes / Chapter 6 .5 --- Comparson of land use changes of the study area / Chapter 6.5.1 --- Land-use change comaprison / Chapter 6.5.2 --- Rural-to-urban changes / Chapter 6.5.3 --- Rural-to-rural changes / Chapter a. --- Origins of wet cropland and market gardening / Chapter b. --- Origins of woodland / Chapter c. --- Origins of fish ponds / Chapter 6.5.4 --- Conclusions / Chapter Chapter Seven --- Conclusion --- p.175 / Chapter 7.1 --- Land use change in the urban fringes in the Zhujiang Delta ---a comparison / Chapter 7.2 --- the applicability of western theories on land use change to the Zhujiang Delta / Chapter 7.3 --- Remote sensing method as an application for land use change monitoring in China

No description available.

This thesis examines the potential of the indigenous right to internal self-determination as a framework accommodating the demands of the Niger Delta Peoples for Self-determination within the sovereignty of Nigeria. The unsustainable exploitation of crude oil in the Niger Delta resulted in the ecological devastation of the region and adversely affected the Niger Delta People's subsistent traditional mode of using their lands. The response of the Niger Delta People was originally to seek redress by instituting legal actions in Nigerian courts. The failure of the majority of these actions, and the combined factors of the exclusion of the Niger Delta People from the process and proceeds of the oil industry and their marginalization in the political and administrative structure of Nigeria resulted in the demand by the Niger Delta People that Nigeria recognize their right to self-determination. They justified this demand for self-determination with the arguments that:  Their dispossession from their lands by the government in Nigeria was akin to the exploitation of indigenous peoples in the Americas by colonial settlers.  The unsustainable exploitation of resources in their territory placed them in the same position as colonized peoples experienced under foreign domination in the era of colonization. In a bid to protect her sovereignty, Nigeria does not recognize the rights of self-determination or 'peoplehood' or even minority status of any ethnic groups within Nigeria. This thesis argues that the indigenous right to internal self-determination is a framework that has the potential to bring lasting solution to the conflict between the Niger Delta people and the government of Nigeria for the following reasons:  Indigenous internal self-determination prescribes a category of self-determination that is consistent with the sovereignty of states because it recommends inter alia autonomy with the territories of states. Indigenous internal self-determination provides a regime for sustainable development of resources as it recommends inter alia that states recognize the right of indigenous peoples to participation, consultation and free prior informed consent in the exploitation of resources in indigenous peoples' territory.

The records or both the faunal remains and artifacts recover d from the St.Mungo Cannery site in the Fraser Delta, British Columbia during 1968-1969 are analysed quantitatively for evidence of processual cultural change. Descriptions of the site and site habitat are given, and methods used to recover, describe, and analyse the two records are detailed. The patterns of variation through time are given in tables of the relative frequencies of types found in excavation units Cl and C2. Multidimensional scalogram analysis is used to delineate and visually present the separation of components. An attempt is made to distinguish cultural variation in the two records from non-cultural variation produced by sampling procedures, and to control for the latter. The relationship between sample size and the number of artifacts and faunal types found is statistically demonstrated as a major sampling error . Some comparisons are made between the patterns of variation observed in faunal and artifact types theoretically related as evidence of particular activities. The information contained in the faunal record is found to be additional as well as parallel to that contained in the artifact record. / Graduate