The Stefan-Maxwell equations are a system of nonlinear partial differential equations that describe the diffusion of multiple chemical species in a container. These equations are of particular interest for their applications to biology and chemical engineering. The nonlinearity and coupled nature of the equations involving many variables make finding solutions difficult, so numerical methods are often used. In the engineering literature the system is inverted to write fluxes as functions of the species gradient before any numerical method is applied. In this thesis it is shown that employing a mixed finite element method makes the inversion unnecessary, allowing the numerical solution of Stefan-Maxwell equations in their primitive form. The plan of the thesis is as follows, first a mixed variational formulation will be derived for the Stefan-Maxwell equations. The nonlinearity will be dealt with through a linearization. Conditions for well-posedness of the linearized formulation are then determined. Next, the linearized variational formulation is approximated using mixed finite element methods. The finite element methods will then be shown to converge to an approximate solution. A priori error estimates are obtained between the solution to the approximate problem and the exact solution. The convergence order is then verified through an analytic test case and compared to standard methods. Finally, the solution is computed for another test case involving the diffusion of three species and compared to other methods.

Lake sturgeon, recently recommended to be listed as an endangered species under the Species at Risk Act, inhabit the various impoundments of the Winnipeg River system. Downstream passage through hydroelectric generating stations represents one of the major data gaps in our understanding of how hydroelectric development may be impacting lake sturgeon populations. Acoustic telemetry was used to investigate coarse-scale movements of juveniles, sub-adult and adults throughout the Slave Falls Reservoir, a 10 km long Winnipeg River impoundment, to assess patterns of downstream passage susceptibility and investigate fine-scale movements in the vicinity of the Slave Falls Generating Station. Movements of juveniles and sub-adults were generally restricted to areas of interconnected deep-water habitat, with movements through the shallow river narrows that sub-divide the Slave Falls Reservoir being rare. Adults did move through these narrows, albeit infrequently. Juveniles and sub-adults tagged in the lowermost section of the reservoir, as well as several adults tagged throughout the reservoir, were found to periodically utilize habitat immediately upstream of Slave Falls, where they would be susceptible to entrainment. Mean entrainment rates were estimated at 3.1% per year for adults tagged throughout the reservoir, and 17.9% per year for sub-adults tagged in the lowermost section of the reservoir. Fine-scale movement tracking revealed that three of eleven observed downstream passage events occurred via bottom-draw regulating gates, while another four events were also reasoned to have occurred via this route. The routes of the remaining four could not be determined. Eight of the eleven downstream passage events observed in this study were survived. While the survival of the remaining three fish could not be confirmed, it is highly likely that they also survived. Length-at-age analysis, supported by genetic methods, revealed that 23 of 151 (15.2%) of the lake sturgeon between 525 and 750 mm (fork length) captured in the 6 km stretch of river downstream of Slave Falls were fast-growing outliers, reasoned to have passed downstream through the Slave Falls Generating Station.

Wetland value is threatened by invasive plant species such as Reed Canarygrass (Phalaris arundinacea). Hence the research objectives of this project were to determine if reed canarygrass abundance has an effect on plant species diversity and assess the effectiveness of novel treatments on reed canarygrass control in a constructed wetland. Four treatments (mowing, herbicide, mowing plus herbicide, and a control) followed by broadcast seeding were applied to regulate growth of reed canarygrass. Principal components analysis, biodiversity measures, and ANOVA were used to identify community composition, quantify biodiversity values and identify treatment differences respectively. Results indicated differences in species composition between east and west blocks of the study site, reed canarygrass abundance appears to keep plant species diversity low, indigenous species were rare, and reed canarygrass was resistant to treatments.The results of this study are not surprising considering there is little evidence that treatments for reed canarygrass control are effective.

Infection with challenge virus standard-11 (CVS) strain, a laboratory fixed rabies virus strain, induces neuronal process degeneration in both in vivo and in vitro models. CVS-induced axonal swellings of primary rodent dorsal root ganglion neurons are associated with 4-hydroxy-2-nonenal staining indicating a critical role of oxidative stress. Mitochondrial dysfunction is one of the most important causes of oxidative stress. We hypothesized that CVS infection induces mitochondrial dysfunction leading to oxidative stress. We investigated the effects of CVS infection on several mitochondrial parameters in different cell types. CVS infection increased electron transport chain capacity, Complex I and IV activities, but did not affect Complex II-III, citrate synthase, and malate dehydrogenase activities. CVS maintained normal oxidative phosphorylation capacity and proton leak, indicating a tight mitochondrial coupling. Possibly as a result of enhanced Complex activity and efficient coupling, a high mitochondrial membrane potential was generated. CVS infection reduced the intracellular ATP level and altered the cellular redox state as indicated by high NADH/NAD+ ratio. CVS infection was associated with a higher rate of hydrogen peroxide production. We conclude that CVS infection induces mitochondrial dysfunction leading to ROS overgeneration, oxidative stress and neuronal process degeneration.

I investigated how orchid biology, floral morphology, and diversity of surrounding floral and pollinator communities affected reproductive success and hybridization of Cypripedium candidum and C. parviflorum. Floral dimensions, including pollinator exit routes were smallest in C. candidum, largest in C. parviflorum, with hybrids intermediate and overlapping with both. This pattern was mirrored in the number of insect visitors, fruit set, and seed set. Exit route size seemed to restrict potential pollinators to a subset of visiting insects, which is consistent with reports from other rewardless orchids. Overlap among orchid taxa in morphology, pollinators, flowering phenology, and spatial distribution, may affect the frequency and direction of pollen transfer and hybridization. The composition and abundance of co-flowering rewarding plants seems to be important for maintaining pollinators in orchid populations. Comparisons with orchid fruit set indicated that individual co-flowering species may be facilitators or competitors for pollinator attention, affecting orchid reproductive success.

Pennisetum Rich, is one of the most important genera in the family Poaceae because it includes forage and crop species such as Pennisetum purpureum Schumach. and Pennisetum glaucum (L.) R. Br. Both P. purpureum and P. glaucum have a number of cultivars and varieties arising due to natural crossing which are very difficult to distinguish morphologically. P. purpureum and P. glaucum also hybridize naturally because they are protogynous and cross pollinated. The resulting hybrids are highly sterile and resemble P. purpureum. Lepidopteran stem borers cause great yield loss in maize produced by resource-poor farmers in Africa and are managed by habitat management or push-pull strategies, in which P. purpureum cultivars and hybrids are used as a trap crop. The aims of this project were to genotype different P. purpureum cultivars and hybrids using Amplified Fragment Length Polymorphism (AFLP) as well as Random Amplified Polymorphic DNA (RAPD) in order to identify cultivars and hybrids and possible misidentifications, assess the congruency of results between AFLPs and RAPDs and to attempt to relate these results to the oviposition preference of Chilo partellus for different P. purpureum cultivars. The individuals to be fingerprinted were collected from several countries in sub-Saharan Africa, a few from the USA and one from China. The AFLP analysis of these individuals were done with primer combinations EcoRI/MseI and Mlul/Msel on polyacrylamide gels and an ABI 3130 xl Genetic Analyzer respectively. The automated sequencer visualized more bands than the polyacrylamide gels. The RAPD technology was not developed any further after 17 primers were tested and no polymorphic bands detected. Overall results indicated that cultivars did not cluster according to geographical origin, and cultivars known by popular names did not always cluster together, indicating diversity within the cultivar or misidentifications. An example of a misidentification is the cultivar Green Gold being no other than cultivar Harare, or cultivar Swaziland 3 being cultivar Sanitas. Proper management by nursery managers cannot be stressed enough, as this will prevent plants getting mixed up, causing confusion. There was no relationship between the relatedness of cultivars and moth oviposition preference. The AFLP technology could be a powerful tool for the DNA fingerprinting and molecular characterization of this grass species, but poor germ plasm management negates its application. / Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2008.

This dissertation considers faunal recoveries from a selection of archaeological sites located in the Canadian Northeastern Plains that date between AD 1000 and 1600. These faunal assemblages derive from three different archaeological cultures that are thought to reflect different subsistence orientations. The analysis quantifies this variability by assessing the taxonomic abundance and intensity of bone processing evident in the recoveries. At issue is determination whether variability in the faunal assemblage reflects differences in subsistence economy deriving from the diverse origins of these societies. This requires control over other potential contributors to variability. This includes ecological comparability of the site localities, consistency of excavation, sampling and analytic methods, and similarities in site function. Particularly important is determination that the selected sites reflect comparable seasons of site occupation. This latter consideration is important since the established archaeological and ethnological literature suggests that both available resources and the economic orientation of resident populations varied significantly with season. To this end, a major research component focused on the development of more refined means of determining the season of site occupation by measuring the degree of osteological development of recovered foetal bison bones. The creation of linear regression equations based on these measurements will allow applied archaeologists to establish season of site occupation without the need for a large, difficult to obtain foetal bison comparative collection. The analysis suggests the variability in the faunal assemblages occurs independently of site cultural affiliation, and might reflect economic activities conditioned by more finely divided seasonal divisions than is apparent with the conventional four-season model deriving from agrarian European societies. Aboriginal language markers, specifically moon-names, were used to identify significant biophysical and bison reproductive events. By placing the six sites within Aboriginal concepts of seasonality, animal food subsistence choices are better understood. These results have implications for the classification scheme archaeologists have used to define subsistence strategies.

Our planet is currently in the midst of a mass extinction event. Plants and animals are dying off at a rate undocumented since the dinosaurs went extinct 65 million years ago. Unlike earlier extinction events, however, the current ecological crisis is primarily being driven by a single species – homo sapiens. Although a seemingly overwhelming issue, environmental non-governmental organizations (ENGOs) have dedicated themselves to ensuring strong species protection. In Canada, these interest groups launched and sustained a successful national campaign for federal endangered species legislation that culminated in the enactment of the Species at Risk Act (SARA). While ENGOs‟ campaign for protective legislation has been well-documented by scholars, there is a dearth of research regarding ENGOs‟ strategies following the passage of SARA. In order to address this knowledge gap, this thesis examines and compares the strategies employed by interest groups in both the pre- and post-passage stages of the Act. After conducting qualitative interviews with seven representatives of Canadian-based ENGOs, this study finds that following the passage of SARA interest groups, dissatisfied with the government‟s weak implementation of the Act, decided to overhaul their strategic approach and shifted the species at risk issue to three new institutional venues: the boardrooms of private corporations, the Commission for Environmental Cooperation (CEC), and the domestic judicial arena. The thesis concludes that, despite inherent challenges, shifting institutional venues can be a successful strategy for ENGOs faced with a government reluctant to implement the hard-won legislative commitments. This work may prove to be particularly pertinent for other non-governmental organizations facing similar obstacles. / Graduate

Mountain ecosystems are considered highly sensitive to the impacts of climate change, and are experiencing a magnitude of change that far exceeds global averages, particularly with respect to increases in average temperature and precipitation. As such, scientists are predicting a rapid habitat reduction or even the loss of the coolest climatic alpine zones, thus threatening the continued survival of high elevation specialists. However, many of these ‘doomsday’ predictions are based primarily on models with coarse-resolution changes to atmospheric climate parameters, and do not take into account the potential buffering effects of other environmental gradients known to structure alpine plant communities, related to topography and soils. To assess the accuracy of predictions regarding the state of vulnerability of alpine plant communities to climate change, this thesis examined the relative importance of climate, topography and soils as determinants of regional alpine plant diversity for all species, as well as for forbs, graminoids and woody species separately, in alpine meadows of southwestern British Columbia. Through redundancy analyses and variation partitioning, results show that topography and soils are more important than climate as determinants of regional alpine plant diversity. Within these groups, elevation, slope, soil moisture and mean summer temperature were most significant. Interestingly, precipitation played only a small role, even though the study area spanned a precipitation gradient of over 1200 mm/year. The stronger influence of temperature, especially for woody species beta diversity, supports findings of shrub expansion in arctic-alpine systems. The lower importance of climate as a determinant of regional alpine plant diversity, especially for forbs, the dominant life form in alpine meadow ecosystems, suggests that these productive environments may be more resilient to on-going changes in atmospheric climate conditions than previously believed. / Graduate

Minuartia verna (L.) Hiern and Thiaspi alpestre L. are recognized as relict elements of a preglacial montane flora in the British Isles and, as such, display a markedly disjunct distribution pattern. Their present-day distribution shows a close association with metalliferous mine workings, particularly in the Pennines, where both species have become prominent components of the flora of calcareous lead mine wastes. By comparison with M. verna, T. alpestre is more restricted in its distribution and is a rarer species. The work reported in this thesis attempted to provide an explanation for this pattern of distribution in the southern Pennines on the basis of comparative studies of the autecology and genecology of the species, their population biology and dynamics in the field and their responses to competition from other species. Both field and laboratory studies confirmed that the two species were highly tolerant of the heavy metals lead, zinc and cadmium. Short- and long-term solution culture experiments on tolerance and uptake of these heavy metals by a range of populations of both species are reported. Tolerance to other toxic metals was also investigated. T. alpestre showed superior tolerance to M. verna in these experiments, and emerged as a metal-accumulating species. M. verna by contrast, operated some degree of metal exclusion, but metal uptake and distribution differed for the various metals in both species and seasonally. Differences in metal tolerance and uptake characteristics alone could not explain the different local distribution patterns in the field, as sites of similar metal status are colonized by both the two species together and by M. verna alone. A study of inter-population variation in morphological characters showed considerable genetically-based variation in both species. M. verna was however more variable. Some of the variation detected was interpreted as being ecotypic in origin. The contrasting breeding of the two species and their seed biology are considered to be major factors in explaining the present-day distributions of the two species. The tendency for inbreeding in T. alpestre has severely limited its genetic variability within populations and potential for spread. Seedling mortality of both species in their natural habitats is very high, and survival can be related to early shelter effects of neighbouring plants. Both species, however, emerge as weak competitors as predicted from their preference for open habitats with much more bare ground. The relevance of these studies to the interpretation of the present-day global distribution of the two species and their evolutionary biology is discussed.