How changes of past vegetation and human impact are documented in lake sediments : paleoenvironmental research in Southwestern Germany, a review

During the last four decades, sediment cores were collected from the deepest zones of >30 small lakes in south-west Germany to investigate archaeological questions about settlement and land use history in Central Europe. The primary aim was to establish well-dated pollen profiles with very high temporal resolution. A major focus was to reconstruct the extent and intensity of land clearing during the Neolithic, the Iron Age, the Roman Period as well as through the Medieval timeframe in context with intermittent recovery periods during political and economic crises. In southwestern Germany, lake sites are not evenly distributed, but rather restricted to the formerly glaciated landscapes of the Northern Alpine foreland, including Lake Constance and the Black Forest. The most important results are as follows: 1. Central basinal sediments of small lakes are the best archives to study environmental change, past human impact, and vegetation. 2. The lakes reflect the environment and its change, triggered by natural and anthropogenic factors. 3. Lakes in areas with silicic bedrock have much lower sedimentation rates than lakes in the carbonate-rich North Alpine foreland in Germany. 4. Human impact causes sedimentation rates to increase by different rates, depending on the magnitude of impact and system sensitivity; in most cases, lamination disappears from the sedimentary record. 5. The small lakes integrate local landscape history, whereas the larger lakes integrate over larger catchments and record regional signals. 6. During the Late Weichselian and early Holocene, the landscape history of Southwestern Germany was rather uniform on a regional scale. 7. Landscape history from the middle Holocene onwards was more and more impacted by man, resulting in a variety of local and regional effects that are recorded in these lakes. 8. Overall, climate and natural factors determined the environmental settings, and people preferred regions with fertile soils and warm climate for settling and farming.