GeloriniPhD (PDF , 6973kb) - University of York

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CHAPTER 1 Diversity and ecology of tropical African fungal spores Geel, 1978, 1986, 2001; van Geel et al., 1981, 1989; Gill et al., 2009; Feeser and O’Connell, 2010; Kramer et al., 2010; Montoya et al., 2010; Mudie et al., 2010) and in archaeological contexts (van Geel et al., 2003; Zong et al., 2007; Cugny et al., 2010; Gauthier et al., 2010; McAndrews and Turton, 2010). Agricultural societies and domesticated animals have created a range of new habitats for fungi. Consequently the mycoflora of settlement sites and the surrounding cropland, pastures and hay meadows reflects these land-use and land-cover changes with different fungal assemblages relative to the original, undisturbed natural ecosystems. Up to now, the large majority of fungal and other NPP ‘Types’ have been recorded in European peat and lake deposits (for an overview of the palaeomycological literature see van Geel and Aptroot, 2006). In general the remains of fossil fungi in Quaternary deposits are almost exclusively ascospores, conidia and chlamydospores produced by Ascomycetes (including their anamorphs). Most of them are thick-walled and highly melanised (dark-pigmented). Many thin-walled spores, which disperse better and commonly occur in samples of atmospheric dust, either do not preserve in lake and peat sediments or are not recognizable after the chemical treatment used to prepare pollen samples for microscopic analysis. The use of fossil fungal spores to enhance palaeoenvironmental studies has been particularly limited in equatorial Africa, where an initial attempt to analyse fungal spores in lake sediments was conducted by Wolf (1966, 1967). Jarzen and Elsik (1986) studied fungal palynomorphs from recently deposited river sediments in Zambia. They described, illustrated and classified fungal palynomorphs with form-generic names according to the system proposed by Elsik (1976), and could refer some of the fungal palynomorphs to extant taxa. The only actuo-mycological studies in Kenya were conducted by Caretta et al. (1998, 1999). One recent application of fungal spore palaeoecology has been carried out at the Munsa archaeological site in Uganda (Lejju et al., 2006). Spores of Kretzschmaria (syn. Ustulina), a mild parasite causing soft-rot of wood on several tree species (van Geel and Andersen, 1988) indicated that the mid-Holocene landscape at Munsa was relatively forested. Presence of ascospores of the obligatory dung fungus Sporormiella, together with the less stenotopic dung fungi Cercophora and Sordaria type suggested that large herbivores inhabited the Munsa area at that time (Lejju et al., 2005). Given the age of the sediments and the absence of archaeological evidence for pastoralism in western Uganda prior to ca. 3000 BP, this dung was probably produced by wild herbivores such as elephants. Fungal spores from later periods at Munsa were attributed to domesticated livestock (Lejju et al., 2005). To stimulate more widespread application of NPP palaeoecology in tropical African contexts, we studied fungal spores and selected other NPPs in the 25,000-year sediment record of Lake Challa in southeastern Kenya. Our primary objectives are to 1) assess the overall taxonomic diversity of East African NPPs, and 2) to use the stratigraphic turnover of fungal taxa during the major climate and environmental changes marking the Glacial-to-Holocene transition as a guide to their potential as ecological indicators. We compare the NPP record with selected pollen curves of common African trees and herbs, and with independent proxies of regional climate (temperature and rainfall) history to study relationships that might elucidate habitat requirements of individual NPP taxa. This paper does not concern the ecosystem shifts and climatic interpretation of the pollen record itself, as this will be presented in a separate publication. Instead we focus on documenting and describing the main types of fungal spores and some other NPPs, and on evaluating the potential of fossil NPP assemblages to contribute to multi-proxy reconstructions of past environmental change in tropical Africa. 1.2. Material and Methods 1.2.1. Study site and material Lake Challa (3° 19’ S, 37° 42’ E) is a 4.2 km², ca. 94 m deep crater lake, filling a steep-sided volcanic caldera at 840 m elevation immediately southeast of Mt. Kilimanjaro (Fig. 1.1a-b). In this equatorial location, twice-yearly passage of the Intertropical Convergence Zone over the adjacent western Indian Ocean creates a bimodal rainfall pattern, with southeasterly monsoon winds bringing ‘long rains’ from March to mid-May and northeasterly monsoon winds bringing . 42 .
Equator b 0° Altitude (m) a >3000 2000-3000 1000-2000 500-1000 ice 0-500 rock, sparse ground cover 2°S alpine grassland subalpine Erica bush subalpine grassland montane forest open woodland open bush- & grassland riverine forest herbaceous swamp 4°S rainfed tree & shrub crops flooded herbaceous crops rainfed herbaceous crops Kibo MOSHI Mawenzi Mabungo Himo Mau Escarpment Loita Hills . 43 . 36°E 38°E Mt Kilimanjaro Mt Meru Mt Kenya CHAPTER 1 Diversity and ecology of tropical African fungal spores Fig. 1.1. Situation maps of Lake Challa in equatorial East Africa (a), regional topography (b) and vegetation (c). Natural vegetation at elevations below ~2000 m is deciduous wooded grassland and bushland with 15-40% crown cover (White, 1983), adapted to a tropical monsoonal climate with pronounced seasonal drought. Near Mt. Kilimanjaro most closed woodland and a substantial portion of the open woodland has been converted to cropland (hatched areas indicate that >50% of the land is under agriculture). Open bush- and grasslands with patches of open woodland in the vicinity of the Challa caldera are relatively undisturbed. Topography (b, elevations in meter a.s.l.) from Oyaya (2005); the vegetation distribution is derived from Landsat TM images taken in 1995 (Di Gregorio, 2002). Aberdare Range Lake Challa 100 km Lumi TAVETA Chyulu Hills Pare Mts Lake Challa c Taita Hills KENYA TANZANIA Usumbara Mts no data Tsavo N 10 km b c
Page 3: 2011 Thesis submitted in partial fu
Page 7: Voorwoord . 7 . VOORWOORD Aarde, wa
Page 10: DANKWOORD / ACKNOWLEDGEMENTS door K
Page 14 and 15: TABLE OF CONTENTS A.1. Septated spo
Page 17 and 18: Abstract . 17 . ABSTRACT In tropica
Page 19 and 20: Introduction . 19 . INTRODUCTION
Page 21 and 22: . 21 . INTRODUCTION Atlantic Ocean
Page 23 and 24: 1 Figure 2 Global Land-Cover 2000 m
Page 25 and 26: Fig. iv. Rainfall variation in east
Page 27 and 28: . 27 . INTRODUCTION metallurgy main
Page 29 and 30: . 29 . INTRODUCTION analysis of fos
Page 31 and 32: . 31 . INTRODUCTION (iv) illuminate
Page 33 and 34: . 33 . INTRODUCTION Coniochaeta spe
Page 35 and 36: . 35 . INTRODUCTION university pres
Page 37 and 38: . 37 . INTRODUCTION Mumbi, C.T., Ma
Page 39 and 40: . 39 . INTRODUCTION lipids in an eq
Page 41: . 41 . CHAPTER 1 Diversity and ecol
Page 45 and 46: . 45 . CHAPTER 1 Diversity and ecol
Page 47 and 48: 1.3.1. Descriptions and illustratio
Page 49 and 50: Type HdV-1005: Brachydesmiella sp.
Page 51 and 52: Type HdV-1020 (Plate II) . 51 . CHA
Page 55 and 56: Type HdV-1051 (Plate III) . 55 . CH
Page 63 and 64: RefeRences . 63 . CHAPTER 1 Diversi
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Page 72 and 73: CHAPTER 2 Modern non-pollen palynom
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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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APPENDICES L. Kanymukali Identifica
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Photograph by Bob Rumes Front cover
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