In the contemporary built-environment the focus is very much on environmentally conscious design or so-called ‘sustainable’ design- or even the generic labelled ‘green’ architecture. Despite this popular and supposedly informed preoccupation with the importance of the role of ecology in architecture, ‘green’ architecture is usually fixated on energy efficiency within the envelope of an individual building. This dissertation questions this limited, and often artificial and technologically driven, relationship between man and ecology. Fundamentally it questions the role of architecture as negotiator in this relationship. The author proposes an alternative way of viewing ecologically conscious architecture, where the intent of the architectural intervention is to respond directly to a given environmental issue and where its existential impact relates to its surrounding situation and the tension between man and ecology existing within the landscape, instead of turning its focus inwards to achieve isolated ‘environmental’ efficiency. Examples of such a specific issue, context and program with a collective goal of achieving these aims are hence forth elaborated on in the content of this dissertation. / Dissertation MArch(Prof)--University of Pretoria, 2014 / Architecture / MArch(Prof) / Unrestricted

Doctor of Philosophy / Department of Biology / John M. Blair / Juniperus virginiana, an important woody plant invader in the U.S. Central Plains, has increased considerably in density and cover in large areas previously dominated by tallgrass prairie. Change in the phenology and nitrogen use efficiency of the dominant plant communities as J. virginiana replaces native prairies may lead to increased plant productivity and biomass accumulation, but may also alter the microclimate and litter quality that affect soil microbial communities responsible for key soil processes. I have focused my investigations on changes in key soil processes that could lead to differences in soil N availability, as well as changes in ecosystem C and N pools and fluxes as J. virginiana expands into native grasslands. Juniperus virginiana forest soils exhibit greater cumulative annual net N mineralization (11.52 ± 0.38 µg N g¯1 soil y¯1) compared to prairie soils (7.90 ± 0.26 µg N g¯1 soil y¯1) (F = 60.67, P = 0.016), yet slightly reduced potential soil C flux. Examination of internal soil N cycling revealed that both J. virginiana and prairie soils minimize potential soil N losses, by rapid microbial immobilization of inorganic N, and constraining nitrification via substrate limitation or environmental constraints. Leaf-level photosynthetic nitrogen use efficiency (NUE) was over a magnitude higher in the dominant grass, Andropogon gerardii, but high annual ecosystem-level NUE and greater soil N availability may contribute to the higher productivity and rapid accrual of C in newly established J. virginiana forests. Increased plant productivity and elimination of fire in J. virginiana forests have allowed at least 80,000 kg ha-1 increase in ecosystem C storage in about half a century. Soil organic C, an important long-term sink, has also increased significantly in J. virginiana forests, with approximately 34% replacement of C4 grass-derived soil C with new C from trees in the A-horizon. The observed high productivity of J. virginiana and increased N availability necessary to support continued plant biomass accumulation are possible because of substantial (~ 44%) increase in ecosystem N in measured pools, which is a likely a result of reduced volatilization of N from biomass burning, possible increased exogenous N inputs, and/or N translocation from deeper soil horizons. Reduced fire return intervals in prairie provide an opportunity for J. virginiana to establish and facilitate N accrual, which may allow this species to accelerate is own establishment through creating conditions of increased N availability and efficient utilization of N.

Thesis (MSc. Agriculture (Remote Sensing)) -- University of Limpopo, 2015 / Savannas are the most important ecosystems for raising livestock in Africa. In the past 50 years, evidence has shown that savannas throughout the world are being altered by bush encroachment. This is an ecological succession process where perennial plants such as shrubs and trees replace annual vegetation. This reduces the amount of palatable fodder and directly threatens livestock productivity in many localities. This study evaluated long-term bush encroachment using multi-date Landsat Thematic Mapper (TM) images 1989, 1990, 1993, 1995, 1999, 2004 and 2008 to reconstruct changes in spatial distribution of trees and shrubs at the Towoomba Reseach Station over a period of 19 years, from 1989 to 2008. Grasses and woody species were classified using unsupervised classification and Normalised Difference Vegetation Index was used to assess forage productivity and change in vegetation with years. The study was carried out at Towoomba Research Station in Bela Bela, Limpopo Province, South Africa. The study revealed that bush encroachment is a natural process and is independent of the grazing patterns. The results show that if not monitored encroaching species will make it difficult for grazers to get underneath the trees and also disturb the photosynthetic process of grass thereby replacing the grass. The study further showed that satellite remote sensing has the potential for monitoring rangeland quality. Keywords: Bush encroachment, remote sensing, classification and Normalised Difference Vegetation Index

The increasing rate of urbanization and the problem of road reserve encroachment mean that there is no space for road expansion and sometimes for maintenance and road furniture, these and other problems have exposed the problem of road reserve encroachment. The main aim of this study was to investigate methods of finding the road reserve encroachment in Maseru Lesotho using aerial photos. The study used single image analysis and multiple image analysis methods. In single image analysis, the study used three methods of image classifications to find objects that are in the road reserve. Under classification, the study used both supervised and unsupervised image classifications. For supervised classification, the study used the direct image classification method where the aim was to look for every object found in the road reserve. For the indirect approach, the study looked for the ground to find objects in the road reserve. For unsupervised image classification, the study assumed that small clusters are encroachment. In multiple images analysis, the study used the 2015 and 2017 images to determine permanent objects found to have encroached road reserves. Here the assumption was that encroachment does not change over time, which means that unchanged objects during the change detection have encroached on the road reserve. The confusion matrix was used to tell the best performing method and the results show that the indirect method, both in Qoaling and Maqalika performed best. All the methods showed that there was an encroachment on a road reserve, and found that permanent objects were; houses, shops, and shopping centers. The study recommended the use of images with higher resolution and more bands, also that images be taken frequently.

Meadows are crucial components to larger river watersheds because of their unique hydrologic and ecological functions. Due to climate change, over grazing, and fire suppression, conifer encroachment into meadows has accelerated. In some western regions, nearly half of all meadow habitat has been loss due to conifer encroachment. Restoration of these hydrologic systems requires tree removal. Many studies exist that address the issue of conifer encroachment in montane meadows, however, few studies focus on the role that conifer removal plays on the encroaching meadow. Furthermore, few studies exist that document the hydrologic change from conifer removal and further restoration steps, if any, to take after the removal. The overall research goal is to understand the efficacy of removal of encroached conifers from an encroached meadow (Marian Meadow) for successful meadow restoration. The objectives of this study are to determine (i) quantify the meadow hydrology following removal of encroached conifers, (ii) determine if forest tree removal adjacent to the meadow influences the meadow’s hydrology, and (iii) test three common revegetation techniques for a formerly encroached montane meadow.. Marian Meadow is in Plumas County, CA at an elevation of 4,900 feet. This 45-acre meadow enhancement project is part of a 2,046-acre timber harvest plan implemented by the Collins Pine Company. Soil moisture sensors at one foot below the ground and water table depth sensors at four feet below ground were installed in Marian Meadow and a control meadow in September 2013, with additional soil moisture sensors at three-foot depth installed August 2015. The removal of encroaching conifers from Marian Meadow occurred in June 2015. Electrical Resistivity Tomography (ERT) was used to determine maximum water table depths and climatic variables were measured from a weather station as inputs for the water budget. A groundwater recession curve equation was used to model water table depths between water table depth sensor measurements and ERT measurements. A general linear model was used to determine any statistical significant difference in soil moisture and water table depths prior to and after conifer removal. Revegetation plots were installed at the start of the 2017 growing season to determine the establishment rate for three different techniques (BARE, WOOD, and EXISTING) and three different species of meadow plant. Technique BARE, which removes approximately 10 cm of top soil and disperses seed was statistically significant, yielding the highest population count. Another growing season data collection and control plot is required to draw further conclusions and recommendations. The water balance indicated that the majority of Marian Meadow and the Control Meadow’s water storage can be attributed to precipitation and not upland sources. This hydrologic characteristic is common in dry meadows. The statistical analysis indicated that measured water table depths increased on average by 0.62 feet following conifer removal. The first year following restoration and the second year following restoration yielded statistically significantly different water levels than pre-restoration water levels. The third year following restoration is inconclusive until the end of the 2018 WY data set is available. On average, soil moisture increased by 6.43% following conifer removal and was statistically significantly different in all three post restoration years when compared to pre-restoration volumetric soil moisture content. Additionally, growing season (April through September) water table depths indicated that meadow vegetation communities could be supported in Marian Meadow following conifer removal. The removal of conifers from an encroached meadow appears to promote soil moisture and water table depth conditions indicative of a meadow and meadow plant community types.

English abstract This work aims on influence of local coverage of woody layer on understorey herbs. Expansion of woody species into semi-natural grassland ecosystems is accompanied by increase of local coverage of woody layer. This process leads to changes of environmental conditions in understorey, that is followed by extinction of heliophillous herb species. This works deals with this phenomenon on a small spatial scale. The research took place near former village Tocov, situated in an abandoned landscape in Doupovské hory. This locality is typical example of woody species expansion into species rich grassland. Here, 399 phytocoenological relevés were collected. These relevés are ordered into triplets, that make triangles. There are local coverage of woody layer measured for each relevé. Impact of this variable was tested in two sizes of the observation window. Single relevés present microsites, while whole triplets present sites, where variability of local covarage of woody layer, leading to variability in herb layer, could be distinguished. Number of herb species is linearly negatively correlated with local coverage of woody layer on a smaller scale of single relevés. In whole triplets, increase of local coverage of woody layer, during early stages of woody species expansion, doesn't lead to decrease of...

In the digital age, with the accelerating pace of e-commerce, online platforms such as Amazon, Yelp, TripAdvisor, Facebook, Netflix, Uber and others have gained in prominence. Furthermore, in the wake of the COVID-19 pandemic, even businesses which were heretofore primarily brick-and-mortar have had to shift to a strong online presence in order to adapt and survive; which, while beneficial to all stakeholders, has resulted in dire challenges for the producers/service providers, platform owners, as well as consumers. In my first essay, I investigate the challenges faced by mobility as a service (MaaS) platforms such as Uber and Lyft for managing their demand and the pool of available drivers. On one hand, driver compensation issues in MaaS platforms is a highly discussed topic. On the other hand, the MaaS platforms are expanding to encompass several external businesses in search of profitability. In this chapter, I focus primarily on driver compensation issues in MaaS platforms when the platforms engage in external businesses. I find that in the majority of instances, the driver compensation reduces when the platforms get involved in external businesses; however, there are a few cases, where it leads to an increment in driver compensation, thus benefiting them. The second essay is on the impact of online reviews from digital platforms such as Yelp and TripAdvisor on business performance. Using a data set from Yelp, first, I study the interaction of average rating and number of reviews on business performance; second, how competition affects the interaction effect of the average rating and number of reviews on the focal business' performance. I find that the impact of the interaction of average rating and number of reviews on business performance is different at various levels of average ratings, and the inclusion of competition negatively influences the interaction effect of the average rating and number of reviews on the performance of the focal restaurant. In my third essay, I analyze how the interaction of supplier encroachment and consumer showrooming impacts an omnichannel retailer and her upstream manufacturer, who encroaches the downstream retailer's market with an online direct sales channel. I identify different scenarios in a covered market where either the retailer, or the manufacturer, or both will be better off. Taken together, these three essays provide valuable managerial insights for real world business problems, which will empower researchers in academia and industry managers, and help them improve their businesses and maximize their operational performance. / Business Administration/Marketing

Erosion and weed dominance often limit the recovery of burned piñon-juniper woodlands. Soil water repellency (SWR) is one factor that may contribute to this by increasing overland flow and impeding seedling establishment. In spite of these effects, the extent of SWR within piñon-juniper woodlands is unknown. In this study, the extent, severity and thickness of SWR were sampled across 41 1,000 m2 plots within three 2009 Utah wildfires. Predictive models of SWR were built from ecological site characteristic data collected at each site. Across the study, SWR was found at 37% of the points sampled. SWR extent was strongly related to piñon-juniper canopy cover (r2 = 0.60) and was found to be significantly higher in tree/shrub mound zones (71%) as compared to interspaces (16%). Endorsed predictive models of SWR extent and severity had R2 adj values of 0.63 and 0.61; both models included piñon-juniper canopy cover and relative humidity the month before the fire as coefficient terms. These results suggest that as piñon-juniper canopy cover increases due to infilling processes in the coming years, post-fire SWR extent and severity will increase. As the effects of a changing climate in the Intermountain West link additively with infilling processes to increase the frequency and intensity of wildfires, the net effect will be stronger SWR over a greater spatial extent. To cope with these changes, land managers can apply the predictive models developed in this study to prioritize fuel control and post-fire restoration treatments with respect to SWR.

Sand movement is one of the many environmental problems facing humans in the dry and semi-dry areas of the world. This study has investigated the observed changes in sand dune coverage compared to predictions, and has also assessed the impact of sand movement on human activity in the north western coastal region of Libya. The study used three methods. The first was a statistical model proposed by Bagnold, which correlates wind shear velocity with particle size, in order to predict likely sand movement. It was found that 60% of sand grains within the study area have a diameter of less than 0.25 mm, making them liable to be moved by the wind speeds recorded, particularly from March until September, and mostly in a northerly direction. The sand in the western part of the study area had a greater predicted rate of sand transport compared with the sand in the eastern part, which was related to its origin. The second method involved the analysis of satellite images for four different years; from 1986 to 2003. The land cover in the study area was found to have changed over this time. Sand dune area cover had increased, and there were other changes particularly a decline in forest. The third method was the use of a questionnaire (the respondents being land owners), which showed that there was notable loss of crop production (by about a quarter) due to sand movement, and that land owners mostly used afforestation to help control the sand movement in the region. The observed sand movement did not match the predictions based solely on sand grain size and wind speed, and climatic analyses showed no convincing trends which could explain increased sand movement except perhaps an increase in wind gusts. The thesis concludes that the overriding determinant in greater sand movement over the period studied was the loss of forest from the area due to human impacts, which farmers are having to compensate for by planting trees locally to reduce sand movement.

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