Dissertations / Theses on the topic 'Natural history, southern hemisphere'

Explores many aspects of the Hesperoyucca whipplei (formerly known as Yucca whipplei), a type of chaparral plant that grows in arid regions of Southern California. Five of the subspecies of H. whipplei are individually described and discussed. Its relationship with its pollinator, Tegeticula maculata, is traced and documented throughout the process of a reproductive season. The project examines the historic uses of H. whipplei by the Native Americans as well as its current uses in the modern world. It includes field study lessons and Hesperoyucca recipes.

Includes abstract.<br>Includes bibliographical references (leaves 215-241).<br>The study is focused on four study sites, two in the Western Cape, namely the Bruno section and Lake Michelle and two in southwestern Australia, namely Wambellup Swamp and Devil's Pool. These sites were chosen as they are well situated to investigate the complex interaction between Late Quaternary climate change, the influence of fluctuating sea levels and the impact of human interaction with the environments in question and provide a regional picture of these interactions.

The sand lizard (Lacerta agilis) is a rare, elusive and cryptic reptile species of conservation importance in the UK. Knowledge of its ecology and behaviour has limited the development of a reliable and effective methodology for population monitoring; this threatens to compromise conservation effort. The behaviour of sand lizards varies seasonally, with sex and with environmental conditions, none of which are fully understood. This aim of this thesis is to further our ecological knowledge of the sand lizard, specifically by investigating factors which influence the detection probability of this species and through exploration of population monitoring and estimation methods. The detection rate of both male and female lizards in a captive population was found to be heavily dependent on their sex and reproductive stage. The detection probability of males was higher (39%) before mating than after mating (33%): with pre-mated males this was strongly associated with temperature and time of day; and with post-mated males it was linked to changeable conditions with solar radiation values between 200-700Wm-2. The detection probabilities of females were higher after mating (40%) than before (25%) with additional variations in detection rate during and after egg laying. Pre-mated females were most commonly observed basking in a preferred range of ultra-violet light and post-mated they favoured conditions where the ground surface temperature ranged between 17.5oC and 27.5oC. An intensive capture-mark-recapture study was performed on independent sand lizard populations and pattern matching software was used to assist with the identification of individual sand lizards from their dorsal patterning. The low recapture rate of sand lizards proved problematic and population estimates were generated using Program MARK following amalgamation of the data from each field season: but this nonetheless generated the first estimates of sand lizard populations in the UK, with a maximum mean density of 222Ha-2. The survivorship of males was consistently higher than females (0.67 vs. 0.26) and the detection rates and populations estimates differed between years. A high number of individuals were encountered only once, resulting in wide confidence limits of abundance estimates for this species. The range of microclimates available within a structurally diverse array of heathland vegetation were quantified and found to be more extensive than previously thought. The range of microhabitats within the preferred temperature range for sand lizards increased from Spring to Summer, so the need for a lizard to be in the open, and thus available for detection decreased. The obstacles encountered when attempting to monitor sand lizards populations arise from the unpredictable nature of the species. Future sand lizard surveys should be conducted at times when the detection probability maximised, as described in this thesis. A national monitoring scheme should steer away from absolute abundance estimates of populations and consider the use of occupancy estimation to monitor our remaining populations.

For the present study 106 strandings of Kogia breviceps and 85 strandings of K. sima along the South African coastline between 1880 and 1995 were analysed in order to examine the age and growth, male and female reproduction, diet, stranding patterns, and population genetic structure of both species. Length and weight at birth were about 120cm and 53kg for K. breviceps and about 103cm and 14kg for K. sima. Von Bertalanffy growth curves were fitted to the data and indicated that physical maturity was reached at around 15 years in both sexes of K. breviceps and at 13 years in female and 15 years in male K. sima. Asymptotic length was reached at 306.0 and 286.1cm in female and male K. breviceps and 249.14 and 263.75cm in female and male K. sima, respectively. Maximum ages were16 years for male K. breviceps and 23 years for females and 17 years for male K. sima and 22 years for females. Reversed sexual size dimorphism was suggested for K. breviceps, while in K. sima males were larger than females. Attainment of sexual maturity in males occurred at between 2.5 and 5 years of age in K. breviceps and 2.6 and 3 years in K. sima, corresponding to 241-242cm and 197cm body length, respectively. The maximum combined testis weight comprised 1.04% and 2.00% for K. breviceps and K. sima, respectively, and a polygynous mating system with a roving male strategy was proposed for both species. The sperm morphology for both Kogia species was described and is characterised by 20-25 spherical mitochondria arranged in rows around the midpiece. Attainment of sexual maturity in females occurred at 5 years in both Kogia species, and at 262cm and 215cm body length in K. breviceps and K. sima, respectively. The ovulation rates were 0.9 and 0.7 per year for K. breviceps and K. sima, respectively. In K. breviceps conceptions occurred from April to September and births from March to August, while in K. sima both conceptions and births occurred from December to March. Annual reproduction and a post-partum oestrus was suggested for both Kogia species. The diet of K. breviceps comprised 50 different cephalopod species from 22 families and 17 other prey species, while K. sima fed on 32 cephalopod species from 17 families and six others. Although niche overlap indices between the two species and between groups within each species were high, some differences in diet could be determined, which allow these two sympatrically occurring species to share the same ecological niche off the coast of Southern Africa. An analysis of the stranding patterns revealed that K. sima has a closer affinity to the Agulhas current and to higher water temperatures than K. breviceps, which is supported by differences in the size of the appendages between the two species. The population genetic analysis revealed a high haplotype and nucleotide diversity for K. breviceps in the Southern hemisphere, but a lack of significant phylogeographic structure, indicating substantial gene flow among populations and inhibiting genetic differentiation of local populations, although the South African population was somewhat isolated from others in the Southern Hemisphere. In contrast the data on the phylogeographic structure of K. sima were somewhat restrictive as the majority of the samples originated from South Africa. Nevertheless, both nucleotide and haplotype diversities were markedly lower than in K. breviceps and more similar to those for other small cetacean populations, suggesting a smaller population size for K. sima than for K. breviceps. Although both Kogia species belong to the medium to larger-sized odontocetes their life histories are located near the fast end of the slow-fast continuum of life histories of marine mammals, indicating high mortality rates. The “false-gill” marking and the ability to squirt ink are thought to reflect adaptations to predator mimicry and avoidance.

<p> This dissertation traces the history of cattle grazing at Saguaro NP, Organ Pipe Cactus NM and Fort Bowie NHS in southern Arizona. This collection of studies examines the factors affecting that use, the ranchers who made their living from the landscape, and the federal land managers responsible for sustaining the natural and cultural resources. </p><p> A dominant industry on arid public lands since the Civil War, grazing was altered by a variety of influences: environmental and human-derived. Ranching communities developed from homesteading settlements. Success was determined by climate, topography, and natural resources; social and cultural pressures; economic events and political legislation; and later federal regulations and decisions. </p><p> The first agency to oversee grazing, USFS was under constant pressure to maximize short-term human benefits. The NPS Organic Act of 1916 mandated conservation of natural resources "by such means as will leave them unimpaired for future generations" and yet approved cattle grazing, an extractive use, under USFS management. Park managers were frustrated by grazing practices not under their control. Parks were at a cultural and social disadvantage. Residents and politicians often expressed displeasure at park reservations; communities feared that parks would interfere with local industries. </p><p> Park employees supervised visitors and developed recreation infrastructure; they came with little experience to manage livestock. Lack of funding for research, limited manpower, and political and administrative interference allowed cattle grazing to continue unregulated for decades altering vegetation and enhancing erosion. In the 1960s, changing values from the environmental movement, the waning power of the livestock industry, and the rise of activist scientists impelled NPS to act. Without monitoring data, NPS turned to legal opinions to terminate grazing. </p><p> Now grazing is regulated and carefully monitored. NPS is mandated to incorporate research results into management decisions. Older grazing permits are being retired, but land acquisitions for park additions add new management challenges. Purchasing permits offers a new but financially limited opportunity to protect sensitive lands. Grazing has ended at all three parks, yet ecological changes and historic structures remain. As cultural and administrative legacies, those remnants offer opportunities to interpret a significant regional tradition and an untold controversy.</p>

The worldwide knowledge of the ecology and natural history of the masarid wasps, those wasps which bee-like provision their nest cells with pollen and nectar, is synthesized and discussed putting into context the investigations concerning nesting and flower visiting by southern African masarids conducted by the present author. Masarids are found mostly to favour warm to hot areas with relatively low rainfall and open scrubby vegetation. At the generic level the masarids of the Nearctic, Neotropical and Australian regions are distinct from each other and from those of the Palaearctic and Afrotropical regions combined. No species are shared between regions. Southern Africa is apparently the area of greatest species diversity. In this region, at least, there is a high incidence of narrow endemism. Masarids are associated with a relatively small range of plant families. Where sufficient records are available distinct major preferences are shown between zoogeographical regions. Relatedness of plant preferences between zoogeographical regions is apparent when relatedness of plant taxa is considered. Within a region there is marked overlap in masarid generic preferences for flower families. At the specific level there is marked oligolecty and narrow polylecty. The majority of nesting studies indicate that nest construction, egg laying and provisioning are performed by a single female per nest, however, nest sharing has been alledged for two species. No parasitic masarids have been recorded. Egg laying precedes provisioning. Mass provisioning is the rule. According to species, nests are sited in the ground, in non-friable soil or friable soil, in earthen vertical banks, on stones or on plants. Seven nest types are defined. Three bonding agents, water, nectar and self-generated silk are used. Masarids are evaluated as potential pollinators of their forage plants in southern Africa. The "masarid pollination syndrome", though less broad is shown to fall within that designated melittophily. The case studies considered make it clear that, whereas the masarids visiting some flower groups are members of a guild of potential pollinators, the masarids visiting others are probably their most important pollinators. Increasing land utilization is shown to threaten the existence of narrowly endmic masarid species.

Thesis (M.A.)--Miami University, Dept. of History, 2005.<br>Title from first page of PDF document. Document formatted into pages; contains [1], ii, 89 p. : maps. Includes bibliographical references (p. 70-89).

The aim of this research is to examine the much neglected body of writings on New Zealand and the Maori by German-speaking explorers and travellers during the colonising period of the 1840s to 1880s. To the nineteenth-century breed of visitor from Germany and Austria, 'Old' New Zealand often presented itself as an unexplored field of scientific curiosities, from botany and geology to ornithology and ethnology, at the same time as a paradise for immigrant workers. The investigation begins with an evaluation of the eighteenth-century account of Georg Forster, who accompanied Captain Cook on his second voyage to the South Pacific. Forster's account is entrenched in the early racial stereotypes and theories of the 'savage', and provides the first major primary source for all of German-speaking Europe up to the period under investigation. The second main source to be considered is the dominant 'paradise' image which evolved out of the propaganda of the New Zealand Company and continued right through the colonising era. The principal figures to be examined include Ernst Dieffenbach, the official Company naturalist, Friedrich August Krull, the first German Consul in New Zealand, Ferdinand von Hochstetter, the resident geologist on the Novara expedition, Julius von Haast, the founder and director of the Canterbury Museum, Andreas Reischek, the taxidermist and collector, as well as other notable visitors including Max Buchner, Franz Reuleaux, Otto Finsch, Alexander von Hübner and Robert von Lendenfeld. Thus, it is the goal of this investigation to analyse the perception of New Zealand and the Maori in selected works by German-speaking explorers and travellers who arrived in the colony between 1839 and 1889 through, first of all, confronting the prevailing stereotypes and images inherent in the philosophical attitudes of the eighteenth and nineteenth centuries towards the 'savage' and those present in the 'paradise' rhetoric of the British campaigners of colonisation, and secondly, examining the origins, patterns and evolution of their respective perceptions, impressions and opinions in order to reveal the true extent of their non-British 'Germanic' viewpoint.

An examination of the morphology and photosynthetic physiology of the two dominant families of conifers in the southern hemisphere, the Podocarpaceae and Cupressaceae, was undertaken here in order to describe the physiological limitations which constrain their distribution. A species specific index of drought tolerance was devised which quantified the maximum attainable water-use efficiency of photosynthesis during imposed drought. This index, (ci/c a)min, measured the potential of leaves to photosynthesize under water stress, comparing the maximum draw-down of internal CO2 concentration (ci) below ambient (ca). When operating at (ci/c a)min, the leaf was at the maximum water stress before leaf damage (indicated by an irreversible loss of variable fluorescence and photosynthetic rate) occurred. (ci/c a)min was found to be well correlated with the minimum rainfall within the natural range of the 12 species investigated, and this is strong evidence that the distribution of these species is largely determined by their drought tolerance. Further support for the drought limitation hypothesis came from a comparison of photosynthetic rates (as measured by chlorophyll fluorescence) of conifers in the field. The apparent photochemical electron transport rate (ETR) was found to be significantly reduced in a dry site when compared with a wet site. Most Podocarpaceae, and many Cupressaceae were found to be highly drought sensitive, and probably became increasingly susceptible to extinction during the substantial increase in aridity which occurred in Australia during the Tertiary. The influence of features considered as possible morphological drought adaptations on water loss were also examined. Wax plugs and imbricacy were found to substantially decrease maximum stomatal conductance, with the combination of wax plugs, imbricacy and epistomy reducing conductance to 17% of the value expected on leaves with exposed, unplugged stomata. Competition for light is believed to be another area where conifers suffer due to their lack of broad-leaves. Many podocarp genera appear to have converged with angiosperms, producing discrete, bilaterally flattened short shoots which seem to function as broad-leaves. The degree of shoot flattening, as measured by shoot width, was correlated with the leaf saturation light requirement, broad shoots requiring substantially lower light intensities for saturation. From this it was inferred that the bilaterally compressed short shoot was an adaptation to light competition with angiosperms. Conifers in the southern hemisphere form a surprisingly distinct group which has retained its character since the earliest Tertiary. The late Cretaceous- early Tertiary also saw the radiation of angiosperms, and it has been suggested that this event resulted in the global decline of the Coniferales. By determining how distributions of these taxa are limited today, it was possible to shed some light on whether conifers in the southern hemisphere were simply overrun and replaced by the more competitive angiosperms, or if other factors such as climate change are likely to have played a part. A brief summary of the evolutionary history of conifers in the southern hemisphere leads to the conclusion that decreasing rainfall and fire have been the main influences on conifer extinction.

Research Doctorate - Doctor of Philosophy (PhD)<br>The development of viticulture in Australia in the nineteenth century mostly drew on European models to spread both wine production and consumption in the colonial societies during the nineteenth century. Among these models, France gradually appeared as a specific choice due to the reputation of its wines and its cultural practices in the British world. This thesis intends to analyse the transfers of skills, technologies, vine grapes and experts from various French regions to the Australian colonies of New South Wales, Victoria and South Australia. These three colonies collectively represented the most productive wine district during the nineteenth century and the most evident marks of a French influence. This circulation of knowledge mostly relied on wealthy British colonists’ initiatives in order to develop economically and culturally the colonies. This thesis presents new evidence of the importance of the cross-cultural and transnational aspects which shaped the world wine industry in the nineteenth century. It also shows how Australia instigated these transfers of French practices and ideas and reshaped them to fit its natural, economic, political and socio-cultural environment. Overall, this thesis, situated at the intersection of wine history and transnational history, gives a new insight on the effects of the first wave of globalisation which facilitated the circulation of knowledge, technologies and production models from Europe to the New World. It highlights the importance of interpersonal and interinstitutional exchanges occurring across national boundaries in the development of agricultural production, commodity trade and scientific knowledge. It also questions Franco–Australian transfers as a reflexivity process peculiar to histoire croisée. As such, this research project has been conducted both in Australia and in France as a transnational investigation mixing perspectives from the English-speaking world and the French-speaking world.

The author wrote a dissertation for the Mmed Sc degree entitled The Clinical Natural History of Snakebite in Southern Africa, which dealt with the epidemiology of snakebite and the clinico-pathological events in snakebite victims. This thesis is a sequel on the management of snakebite victims. Publications on the overall management of snakebite in the Southern African region that include original scientific research are those of F.W. Fitzsimons (1912), F.W. Fitzsimons (1929) (assisted by V.F.M. Fitzsimons), P.A. Christensen (1955, 1966, 1969) and Christensen & Anderson (1967). Subsequent books, pamphlets and journal articles have rehashed this knowledge or advocated methods of treatment developed in other countries. An example of the latter is the pressure immobilisation prehospital measure advocated for snakebites in Australia (Sutherland et aL, 1979, 1981, 1995), which I regard as benefiting less than 1% of snakebite victims here and being deleterious in most cases. In view of the paucity of research done in Southern African in recent years, many questions remain unanswered, and some strongly held views are without logical or scientific foundation. Most of these questions arose prior to the writing of this thesis, and others arose when the data were analysed. The following are some questions on the management of snakebite that have still have to be addressed. Is vaccination against snakebite possible and practical? Are folk and traditional remedies advantageous or deleterious? How commonly are they used? Immobilisation of the bitten part and the patient is an internationally recognised aid measure, but is this relevant to the Southern African situation? Tourniquet use in the case of necrotising venoms is considered to aggravate or precipitate necrosis. Does immediate active movement following a bite ameliorate or prevent necrosis without increasing mortality? The majority of clinicians recommend antibiotic prophylaxis, but is this necessary for all snakebites, against which bacteria should antibiotics be administered, and what is the source of these bacteria? Should antivenom be administered to all snakebite victims: for species-specific bites, only if envenomation is present, for severe envenomation, or not at all? Acute adverse reactions to South African manufactured snakebite antivenom has been variously recorded as less than 1% (Visser & Chapman 1978) up to 76% (Moran et al., 1998). What is the truth? Is syndromic management of snakebite efficacious or is it essential to identify the particular snake species? Is the present liberal use of fasciotomy necessary? Is there an optimum time to debride necrotic areas and is surgery necessary at all? Is paresis or paralysis due to neurotoxic envenomation always the result of a post-synaptic block? Would such a block respond to neostigmine or prostigmine in a similar way to post-synaptic anaesthetic muscle relaxants? Is heparin of value when procoagulant toxins induce a consumption coagulopathy? Do fibrinstabilising agents or fibrinolytics have a role? Does the management of pregnant snakebite patients differ from that of non-pregnant patients? Is snake venom teratogenic? Does snake venom ophthalmia frequently lead to blindness? Are steroids, NSAIDs and antihistaminics, which are commonly used in the management of snakebite, of proven value? This thesis attempts to answer these questions and more, and comprises six sections. The first section deals with pre-hospital management, the second with infection which may occur at the bite site wound, the third with SAIMR snakebite antivenom, the fourth with the three envenomation syndromes, the fifth with snakebite in pregnancy, venom ophthalmia and other treatment modalities, and the sixth section includes a summary, appendix and references. Unless otherwise stated, the materials and methods of each chapter are based on 336 snakebite victims admitted to Eshowe Hospital, KwaZulu-Natal, from January 1990 - July 1993 and other victims treated by the author, the data of which have been prospectively maintained. This has been an ongoing process up to the present time.<br>Thesis (MMedSc.)-University of Natal, 2000.

M.Sc., Faculty of Science, University of the Witwatersrand, 2011<br>The aim of this investigation was to explore the relationship between the unidentified and identified fauna from the Still Bay period at Blombos Cave between ca. 77 and 72 ka. The size, breakage patterns and surface modifications of unidentified long bone fragments from the M1 and upper M2 phases were analysed. The results of the analyses were then compared to a sample of faunal remains identified by Klein (Henshilwood et al. 2001b) and Thompson (2008) from the Still Bay layers at Blombos Cave. The length of each fragment was measured to ascertain the degree of fragmentation of the assemblage. Long bone fragments generally become slightly shorter with increasing depth. This may be because smaller fauna are relatively more prevalent in the deeper layers. Cortical thickness of the bone fragments was measured and grouped into small, medium and large categories. These categories were correlated to Brain‟s (1974a) bovid size classes to investigate whether the unidentified faunal remains mimic the identified bone sample in terms of animal size. While small-sized fauna dominate the identified archaeofaunal assemblages at Blombos Cave, the cortical thickness of unidentified long bone fragments suggest that medium-sized fauna was more common. The breakage pattern of each fragment was assessed, indicating that the majority of specimens exhibited spiral fractures. Burning is more common in the unidentified faunal sample than in the identified sample and may have resulted in the relatively low frequencies of cut-marked and percussion-marked fragments. Polished bone fragments may also be a consequence of burning, abrasion or compaction, though its prevalence in the upper M2 with formal bone tools suggests that it was the result of human activities. Higher bone fragment densities in the upper layers at Blombos Cave suggests that changes in human occupation and faunal density patterns during the Still Bay at Blombos Cave may relate to environmental conditions.