GeloriniPhD (PDF , 6973kb) - University of York

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INTRODUCTION Thesis outline In developing this PhD thesis, two key concepts have been essential to assess the value of NPPs as palaeoenvironmental proxy indicators in tropical Africa: (i) insights into modern ecology and current environmental processes as a starting point to interpret past environmental changes, and (ii) multiple-proxy analysis as a comprehensive research approach to obtain better understanding of climate-human-ecosystem relationships. This thesis covers 4 research topics, which are imperative to explore the potential value of NPPs in disentangling the role of human impact and natural climate variability on tropical African ecosystems. In Chapter 1 we study fossil NPP assemblages from the 25,000 year sediment record of Lake Challa, a steep-sided crater lake on the lower East slope of Mt. Kilimanjaro (southeastern Kenya), to explore NPP diversity in a tropical African context. Using the Challa pollen record and two independent proxies of past temperature and rainfall, we also assess the relationship between individual fungal taxa and particular species and biomes of tropical African vegetation, and the history of regional climate change. To capture a significant portion of the overall NPP richness in East African lake sediments, we then analyse modern NPPs from recently deposited surface sediment in 20 small crater lakes in western Uganda, located along environmental gradients of vegetation, land use and lake characteristics (Chapter 2). Using primary taxonomic literature on tropical fungi, we recovered 265 distinct morphotypes, of which 187 tropical African NPPs are presented in an illustrated guide, accompanied by high-resolution photographs and ecological information, when available. Based on an interdisciplinary approach combining fungal spore analysis, vegetation mapping and stastistical modelling, Chapter 3 discusses the effects of land use, habitat diversity and lake properties on modern fungal spore richness and evenness of 24 small crater-lake basins in western Uganda. In Chapter 4 fossil NPP data of high-resolution ~200 year sediment records, contrasting presently undisturbed (L. Chibwera) and human-disturbed (L. Kanyamukali) crater basins, are compared to assess and validate the role of NPPs as palaeoenvironmental indicators for discerning the specific fingerprints of past climatic and human impacts on tropical African lake ecosystems. Finally, a more integrated statement on the outcome of this PhD research, with reference to the main objectives, is provided in the General discussion and conclusion. The strengths and weaknesses of NPPs as new palaeoenvironmental proxy are discussed in a broader scientific and conceptual framework, and some preliminary future-oriented reflections on the application of NPP analysis in African palaeoecological research are cautiously presented. Since this PhD research has strongly benefited from the exploratory study of van Geel et al. (2011), to which I contributed with data processing and NPP identification, this paper in co-auteurship is integrated into this PhD thesis as Chapter 1, with permission of the lead author Dr. Bas van Geel. REFERENCES Alin, S.R., Cohen, A.S., 2003. Lake-level history of Lake Tanganyika, East Africa, for the past 2500 years based on ostracodinferred water-depth reconstruction. Palaeogeography, Palaeoclimatology, Palaeoecology 199, 31-49. Ahmed, S.E., Cain, R.F., 1972. Revision of the genera Sporormia and Sporormiella. Canadian Journal of Botany 50, 419-477 Alpern, S.B., 2005. Did they or didn’t they invent it? Iron in sub-Saharan Africa. History in Africa 32, 41-94. Andersen, S.T., 1979. Identification of wild grasses and cereal pollen. Danmarks geologiske undersøgelse, Årbog 1978, 69-92. Asgari, B., Zare, R., Gams, W., 2007. Coniochaeta ershadii, a new species from Iran, and a key to well-documented . 32 .
. 33 . INTRODUCTION Coniochaeta species. Nova Hedwigia 84, 175-187. Ashley, G.M., Mworia-Maitima, J., Muasya, A.M., Owen, R.B., Driese, S.G., Hover, V.C., Renaut, R.W., Goman, M.F., Mathai, S., Blatt, S.H., 2004. Sedimentation and recent history of a fresh water wetland in a semi-arid environment: Loboi Swamp, Kenya, East Africa. Sedimentology 51, 1301-1321. Banning, E.B., Kohler-Rollefson, I., 1992. Ethnographic lessons for the pastoral past: camp locations and material remains near Beidha, Southern Jordan. In: Bar-Yosef, O., Khazanov, A. (Eds.), Pastoralism in the Levant: Archaeological Materials in Anthropological Perspectives. Monographs in World Archaeology 10. Prehistory Press, Chicago, 181-204. Beinart, W.M., 2000. African history and environmental history. African Affairs 99, 269-302. Bell, A., 1983. Dung fungi. An illustrated guide to the coprophilous fungi in New Zealand. Victoria University Press, Wellington. Bessems, I., Verschuren, D., Russell, J.M., Hus, J., Mees, F., Cumming, B.F., 2008. Palaeolimnological evidence for widespread late 18th century drought across equatorial East Africa. Palaeogeography, Palaeoclimatology, Palaeoecology 259, 107-120. Boko, M., Niang, I., Nyong, A., Vogel, C., Githeko, A., Medany, M., et al., 2007. Africa. In: Parry, M.L., Canziani, O.F., Palutikof, J.P., van der Linden, P.J., Hanson, C.E. (Eds.), Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, 433-467. Bonnefille, R., 1972. Associations polliniques actuelles et quaternaires en Ethiopie (Vallée de l’Awash et de l’Omo). Unpublished PhD thesis, University of Paris VI, Paris, 513pp. Butt, B., 2010. Seasonal space-time dynamics of cattle behavior and mobility among the Maasai pastoralists in semi-arid Kenya. Journal of Arid Environments 74, 403-413. Caseldine, C.J., Turney C., 2010. The bigger picture: towards integrating palaeoclimate and environmental data with a history of societal change. Journal of Quaternary Science 25, 88-93. Christy, J.R., W.B. Norris, McNider, R.T., 2009. Surface temperature variations in East Africa and possible causes. Journal of Climate 22, 3342-3356. Connah, G., 1997. The cultural and chronological context of Kibiro, Uganda. African Archaeological Review 14, 25-67. Conway, D., 2002. Extreme rainfall events and lake level changes in East Africa: Recent events and historical precedings. In: Odada, E.O., Olago, D.O. (Eds.), The East African Great Lakes: Limnology, palaeolimnology and biodiversity. Kluwer Academic Publishers, Dordrecht, 63-92. Conway, D., Allison, E., Felstead, R., Goulden, M., 2005. Rainfall variability in East Africa: implications for natural resources management and livelihoods. Philosophical Transactions of the Royal Society of London, Series A 363, 49-54. Darbyshire, I., Lamb, H., Umer, M., 2003. Forest clearance and regrowth in northern Ethiopia during the last 3000 years. The Holocene 13, 537-546. Davis, O.K., Shafer, D.S., 2006. Sporormiella fungal spores, a palynological means of detecting herbivore density. Palaeogeography, Palaeoclimatology, Palaeoecology 237, 40-50. Dearing, J.A., 2006. Climate-human-environment interactions: resolving the past. Climate of the Past 2, 187-203. Dearing, J.A., Battarbee, R.W., Dikau, R., Larocque, I., Oldfield, F., 2006. Human-environment interactions: learning from the past. Regional Environmental Change 6, 1-16. Dent, C.L., Cummings, G.S., Carpenter, S.R., 2002. Multiple states in river and lake ecosystems. Philosophical Transactions of the Royal Society of London, Series B 357, 635-645. Dixon, J., Gulliver, A., Gibbon, D., 2001. Farming systems and poverty: improving farmers’ livelihoods in a changing world. FAO and World Bank, Rome and Washington, D.C. Driese, S.G., Ashley, G.M., Li, Z.H., Hover, V.C., Owen, R.B., 2004. Possible late Holocene equatorial palaeoclimate record based upon soils spanning the Medieval Warm Period and Little Ice Age, Loboi Plain, Kenya. Palaeogeography, Palaeoclimatology, Palaeoecology 213, 231-250.
Page 3: 2011 Thesis submitted in partial fu
Page 7: Voorwoord . 7 . VOORWOORD Aarde, wa
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CHAPTER 2 Modern non-pollen palynom
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CHAPTER 3 Effects of Land use on th
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CHAPTER 4 Validation of non-pollen
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General discussion and conclusion .
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. 189 . GENERAL DISCUSSION AND CONC
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SAMENVATTING beperkingen (i.v.m. de
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APPENDICES Appendix I. Raw NPP data
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APPENDICES Mahuhura Kitere Katanda
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APPENDICES Appendix II. Raw NPP dat
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APPENDICES L. Chibwera Identificati
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APPENDICES L. Chibwera Identificati
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APPENDICES Appendix III. Raw NPP da
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APPENDICES L. Kanymukali Identifica
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Photograph by Bob Rumes Front cover
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GeloriniPhD (PDF , 6973kb) - University of York

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