NON-POLLEN POLYMORPH-BASED RECONSTRUCTION OF LATE HOLOCENE VEGETATION HISTORY IN WESTERN UGANDA

Previous palaeoecological studies aimed at reconstructing vegetation history in the Central African region have been based on pollen, charcoal and carbon isotope data recorded in terrestrial and lake sediments. This paper details an ongoing attempt to investigate the potential of phytoliths (plant opal silica bodies) and fungal spores as proxies of vegetation history in western Uganda. The research focuses on the last ca. 1000 years, which is a period of major socio-economic and environmental changes in the region. Phytoliths and fungal spores were extracted from a sediment core collected from a previously excavated archaeological site located at Munsa in western Uganda, and used in conjunction with conventional pollen, charcoal and AMS 14C data.

Fossil phytoliths and fungal spores provided additional information in vegetation reconstruction, enabling the discrimination of vegetation types and agricultural activities generally invisible in standard pollen and carbon isotope analyses. The phytolith morphotyes discriminated forest and shrub vegetation dominated by C3 plants from C3 and C4 grasses that are adapted to various soil environments and climatic conditions. The fungal spores indicated possible keeping of herbivores such as cattle. Fossil phytolith records provided evidence that reflect significant vegetation change in the region for the last one thousand years. A relatively wet and forested period existed well over 1000 years, followed by a period of human induced forest clearance that caused a significant decline in forest vegetation and increased grassland-dominated community.