To western researchers, the structure of the grasslands ecosystem on the Northwestern Plains of North America is determined primarily by climate as modified locally by topography, drainage, and sediments. The seasonal availability of the different grasses determines the migratory behaviour of bison which, in turn, influences the movement of human populations. Bison ecology and behaviour also determine the patterns of human aggregation and dispersal. Long-term climatic fluctuations, as measured by effective moisture and temperature, influence the net primary productivity of the short grass plains and, by extension, the size of the bison population.
Lake sediments have been found to carry a natural record of many environmental and geological processes which have occurred on time scales of hundreds and thousand years. They are ideal recorders of high-resolution paleo-environmental changes, because of high sedimentary rates and weak physical disturbance.
Archaeological research has developed numerous approaches to trace past human behaviour and its ability to adapt to different or changing environmental and social conditions. Although differences and changes are generally perceived on very broad temporal and spatial scales in prehistory, methods applied to archaeological remains frequently operate on local, momentary scales.
Pronounced changes in African climate, deserts and tropical rain forest over the last glacial cycles presumably affected human’s way out of Africa. These changes were induced by large changes in ice masses, ocean circulation and monsoon dynamics which, in turn, were triggered by variations in the Earth orbit around the sun and subsequent alteration of meridional insolation gradients.
Human impact, climatic events and palaeoenvironments during the Late Holocene
I am a palaeobiologist analysing sediments as environmental and climate archives. My research mainly concerns the study of ostracod shells, which can provide information on parameters such as salinity, water depth and presence of macrophytes; stable oxygen and carbon isotopes and trace element ratios of ostracod shells serve as additional proxies of environmental change.
In the first CRC Lecture of the winter term 2013/14, Dr. med. Burkhard Rieke will speak about schistosomiasis (Bilharzia), a parasitic disease commonly found in Africa. Freshwater snails are the vectors (intermediary agents) of the parasitic trematodes (Schistosoma sp.), which can infect humans exposed to contaminated water. Several CRC projects are running in Africa and their project members are often exposed to water that might be contaminated by infected freshwater snails.