published_or_final_version / abstract / Geography / Doctoral / Doctor of Philosophy

Climate-sensitive tree ring chronologies and modern climate data are used to produce prehistoric estimates of summer drought for the Mimbres and Pinelawn-Reserve areas in New Mexico. The nature of these estimates are evaluated using tenets of the Anasazi behavioral model. It is concluded that many of the behavioral processes associated with prehistoric populations on the southern Colorado Plateaus can be seen operating within the two Mogollon areas selected for study. As they have on the plateaus, processes in past human behavior can be linked to three factors: prehistoric efforts to intensify agricultural production, fluctuations in population group size, and increases (or decreases) in summer drought.

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The impact of climate on fisheries resources has become a focal point for fisheries research. The objective of this thesis is to describe different aspects of the impact of teleconnections on marine ecosystems within the Mediterranean. Chapter I describes interactions between teleconnection patterns and oceanic variability in the Mediterranean. Atmospheric variability over the Atlantic and Eurasian sector forces oceanic circulation in the western Mediterranean, by altering the route of Atlantic storm tracks. The Indian monsoons are found to be related to gyre and upwelling formations in the eastern Mediterranean. Important links between the Mediterranean Oscillation and hemispheric circulation are also discussed. Chapter II studies the impact of atmospheric and oceanic forcing on the spatiotemporal distribution of chlorophyll-a concentration in the Mediterranean. A number of teleconnection indices with an important role in determining chlorophyll-a concentration are identified, especially for coastal areas, upwellings and gyres. Chapter III has an exploratory nature, with common trends in the landings of 41 fish species from the eastern Mediterranean identified and compared to fishing effort or large-scale environmental drivers. Teleconnections over the Atlantic or El Nino-related teleconnections, filtered by local SST and wind variability, are highlighted as driving forces behind some of the observed common landing trends. Chapter IV focuses on the biological complex of two commercial species, anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus). The results suggest that the West African Summer Monsoon, the East Atlantic Jet and the Pacific North American teleconnection patterns have a consistent correlation with anchovy and sardine distribution and abundance. Relationships between oceanic circulation in the Mediterranean and atmospheric variability over the neighbouring oceanic and continental masses were described and linked to biological variability. Oceanic structures that interrupt the oligotrophic regime of the area are affected by teleconnection patterns and in turn they influence fisheries productivity. Interactions between teleconnection patterns and fisheries can explain a large proportion of the observed fluctuations in marine resources and synchronicity between species and locations. The processes modulating the effects of climatic forcing vary at fine spatiotemporal scales, the different characteristics and habitat requirements of the species and interactions between the species. Further research is essential in order to delineate these effects and improve the management of marine resources in the persistently over-exploited environment of the Mediterranean Sea.

There are new challenges, facing the 21st century and one of them is the discussion around climate change and global warming. This phenomenon brings with it a deeper problem, which is the fact that millions of people have their lives strongly damaged as a consequence of the climate changes. There is no international instrument that protects these climate victims, which in this thesis are referred to as environmental refuges. This thesis focused on trying to evaluate solutions to the problem of environmental refugees. To achieve this we first had a look at the different types of forced migration since it would define which type of solution would suit this type of refugees the best. We had a look at the "Oustees" which are the people who are forced to move due to development projects in the different countries. Then we had a look at Bangladesh as one of the case studies since it is one of the countries at higher risk of suffering the adverse consequences of climate change, which forces many people to move internally or to cross the border to India. We were able to conclude that cross border migration increases tensions between countries and between social groups of the receiving communities. Since these people need protection and since these types of tensions threaten peace and security in some...

The climate of the Neoproterozoic Snowball Earth is tested in the UKMO Unified Model, specifically the HadCM3 climate model. The model is largely left unchanged, but the boundary conditions, both external and initial, are adjusted to create experiments based on the Snowball Earth hypothesis. The model can reproduce multiple equilibrium climates, as have been seen in energy balance models of the Earth's climate. The modelled present day and Neoproterozoic versions of Earth can both reproduce both ice capped and ice covered climate states. Neither can reproduce a climate which remains ice free throughout the year, even with an equilibrated ocean or elevated levels of C02. In all cases the ice free climate reverts toward the ice capped climate after the first polar winter. The modelled Neoproterozoic ice covered climate, that is the climate of Snowball Earth, has a climate very different from the present day. These changes are mostly driven by the lower thermal inertia, latitudinal temperature differences and the changed meridional circulation that results. The weather of the modelled Snowball Earth climate is also very different, dom- inated by a strong diurnal variation due to solar heating, as opposed to the more varied weather in the present day. The model responds well to the conditions of the Snowball Earth climate, with temperatures similar to those predicted by a simple physical model. The model responds less well to high levels of C02 in the Snowball Earth climate. The ice model also allows excessive heat and moisture to escape from the ocean into the atmosphere compared to that that would be predicted from solid ice coverage of the ocean. The exit from a Snowball Earth state was also tested within the model. Neither an decrease in albedo nor an increase in CO2 is unable to increase the temperature of the climate system sufficiently to exit the Snowball Earth state.

A research report submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfillment of the MSc by Coursework Degree (in Resource Conservation Biology) June 2017. South Africa. / Understanding why species occur where they do and, predicting where species might migrate to under different global change scenarios is an important aspect of biodiversity conservation. Regions that harbour high levels of species diversity and endemism arising from sharp local climatic and ecological gradients are highly susceptible to changing conditions. Kumara plicatilis is a tree aloe endemic to the Boland mountain ranges in the species-rich fynbos region in the Western Cape Province of South Africa. The species is currently listed as Least Concern as far as habitat degradation, population decline, invasive species and direct-use threats are concerned although impacts of anthropogenic climate change on this habitat specialist remain undocumented. This study used species distribution models to successfully classify the environmental niche of the species as well as delineate spatial patterns of probable occurrence and abundance based on this niche. In addition, models based on the IPCCs 2014 ‘best-case’ and ‘worst-case’ climate change scenarios provide projections of changes in the spatial occurrence patterns of Kumara plicatilis expected under conditions of shifting climates. Niche-based statistical analyses were further used to draw temporal comparisons between current and future projected ranges to ascertain the degree and properties of shared niche space now and in the future. Results indicate that suitable habitat conditions for the species distribution is irregularly spread around the central and southwestern fynbos region constrained by several climatic and biophysical variables including winter rainfall and temperature conditions as well as vegetation type. The species is expected to experience limited to severe declines in the area of suitable habitat available under mild and harsh climate change conditions, respectively. The patterns arising from these models are in line with the environmental niche measurements which show large degrees of overlap between current and future niche space of the species. These outcomes suggest that Kumara plicatilis displays traits of environmental niche conservatism where unsuitable climate and biophysical conditions can limit its geographic range and local extinction of populations can occur due to global change. Whilst the results of this study offer a useful and initial insight into the possible impacts of shifting climates on this species, outcomes from modeling should be interpreted with caution to reach the best management decisions and conservation action for this endemic species. / MT 2017

A research report submitted to the Faculty of Science in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, 31 August 2012. / Unable to load abstract.

The tourism climate index (TCI) provides information on the levels of comfort for tourism activity based on the climate of a destination. This index has been widely used to quantify the impacts of climate change on tourism at a diversity of destinations. The index is calculated based on the monthly averages of seven variables. To apply this index in South Africa, meteorological datasets of each variable were obtained from the South African Weather Service for 18 locations across South Africa. Each location is climatically distinct and relies on the tourism sector to generate social and economic development within the region. The 18 study sites, are influenced by differences in elevation, the Benguela and Agulhas currents, found along the west and east coast of the country respectively, and by the temporal scale at which summer and winter rainfall occurs across the country. Various data limitations resulted in the need for an adapted tourism climate model in order to calculate the climate suitability of all the chosen locations. The annual mean TCI scores for the period 2005-2014, reveal excellent to ideal climate suitability for tourism at the majority of the locations, with TCI scores ranging between 80.20 and 93.00. However, for the same period, East London, Port Nolloth and Belfast have annual average TCI scores between 74.88 and 79.20, which indicates that their climate suitability is considered to be very good. During the period 2005-2014, the majority of the locations experienced an increase in their climate suitability for tourism. Mean Monthly TCI scores indicate seasonal variations in the climate suitability of destinations across the country. These results suggest that Durban and St Lucia have the most favourable climate conditions for tourism during winter; while Cape Town, Paarl, Port Elizabeth, East London, Port Nolloth and Knysna have the most favourable climate conditions for tourism during summer; and Bethlehem, Bloemfontein, Johannesburg, Kimberley, Ladysmith, Nelspruit, Pilanesberg, Pretoria, Polokwane, and Belfast have the best climatic conditions for tourism during spring and autumn. The difference in average TCI scores across the country and the rate at which these TCI scores change over temporal scales highlights the need for constant monitoring of the climate suitability in these regions, particularly because they are reliant on the tourism sector. Rainfall and average thermal comfort had the most negative influence on the annual mean TCI scores, whilst daytime thermal comfort had the most positive influence on the same TCI scores. Tourism academics and researchers in South Africa were interviewed and they perceive climate change to be a social issue that will only impact the South African tourism sector in the future. The perceptions of the tourism academics and researchers are important as they are often the first people to engage with information pertaining to issues about tourism in South Africa. Although none of the respondents could provide a clear indication of when they perceive climate change to have an impact on the South African tourism sector, the majority of them believe that that TCI can be used as a tool to quantify the impacts of climate change on the tourism sector. This would improve the capacity of tourism stakeholders to adapt to the resultant impacts. However, most of the tourism academics and researchers clearly stipulated that the TCI should be used in conjunction with current climate change and tourism research in the country

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. Johannesburg, August 2016 / Monitoring the status and abundance of mammals, as well as establishing threats to biodiversity in different areas, is an essential management requirement in protected areas. Monitoring mammal species can assist in determining species interactions, patterns of behaviour and is important for further research, policy and management strategies. Water provision has implications for the preservation of wildlife, and is thus a management concern. Numerous studies monitoring mammal water utilisation patterns have employed traditional data collection methods, which are restricted primarily to diurnal observation during specific time intervals. Given the projected future impacts of global climate change on regional water availability, it is essential to investigate current water usage by mammals in the Kruger National Park (KNP), so as to better ascertain likely future water requirements under climate change scenarios. The use of remote photography for scientific observation, investigation and monitoring has many potential benefits, and an innovative and relatively new method through which one can observe mammal water source visitation patterns, is through the use webcams. There has been comparatively little research on mammal water requirements and visitation patterns at water provisioning sites using remote photography as a data collection method. Further to this, there is a gap in our knowledge concerning how daily climate variables (viz. temperature and rainfall) and astronomical conditions control water source visitation patterns at the finer temporal scale. This research primarily contributes to understanding contemporary water source visitation patterns and how this will influence future management decisions. At a broader scale, determining recent visitation patterns is critical in the context of projected future climatic changes and the associated water requirements for mammals of KNP. Webcam images were obtained for the period March 2012 - March 2014, captured at two artificial water sources in the central KNP. A clear divide is exhibited between herbivore and carnivore visitation patterns, with herbivores exhibiting exclusively diurnal patterns and carnivores’ nocturnal patterns. Significant relationships with Tavg intervals demonstrate that the majority of herbivores are shifting their visitation periods earlier in the day per 5°C increase in mean daily temperature, while the majority of carnivores are shifting their visitation periods later in the night per 5°C increase in mean daily temperature, however there is variability of species responses across the two study sites. Under the highest Tavg interval (30°C - 35°C) impala, warthog, southern giraffe, African buffalo and plains zebra exhibit a shift to earlier visitation by 1 – 6 hours, forcing them to utilise the water sources outside of their preferred temporal range. The influence of the timing of rainfall events indicates that the mean number of individual species sightings is significantly larger on days before rainfall compared to days after rainfall. The study highlights that waterdependent herbivores utilise the artificial water sources in relative proportion to their abundance in the central KNP, while water-independent herbivores are avoiding these artificial water sources. The findings of this research could be used to supplement current water provisioning guidelines and plan for water provisioning efforts in future. / TG2016