Reconstructing Holocene landscape development in Mongolia influenced by climate and pastoralism, based on geomorphological archives

• Applicants: Professor Dr. Manfred Anton Frechen; Dr. Michael Klinge; Dr. Barbara von der Lühe; Professorin Dr. Daniela Sauer
• Subject Area: Physical Geography
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429299280

The key question of this project, i.e., since when and to what extent humans have influenced the vegetation pattern in the semihumid to arid forest steppe and steppe regions of Mongolia, has not yet been finally resolved. The archeological record provided by graves and sacral buildings only starts with the Bronze Age (3.5 ka BP). At that time, the nomadic lifestyle, including the whole spectrum of herd animals, was already fully established. However, the preceding period of the transition from the lifestyle of hunters and gatherers to stockbreeding is poorly documented, as artefacts of this period are rare. This project is based on the hypothesis that the development of pastoralism since the end of the Neolithic period led to a substantial change in the vegetation, which in turn triggered an intensification of geomorphological processes. In this project, we will develop and apply an innovative scientific approach that will allow us to identify the spatial and temporal patterns of the onset of human-induced landscape changes at local and regional scale. The approach will include a combination of geomorphological-pedological field and laboratory analysis, numeric dating, charcoal and biomarker analyses. The involved geomorphological-pedological methods are based on the following causal chain: Human activities such as woodcutting, fire-setting and wood pasture caused reduction of forest area and degradation of steppe vegetation by overgrazing. These anthropogenic impacts on the landscape resulted in increased soil erosion, as well as fluvial and eolian sediment redistribution. This causal chain led to a strikingly extensive distribution of stratified sediments in this landscape, containing organic layers, paleosols and charcoal. These sediments represent excellent archives for the reconstruction of the Holocene geomorphodynamics and their chronological course in this landscape. They will be the key study objects of this project. Direct evidence for the first occurrence of domestic livestock and corresponding pastoral economy will be obtained from the analysis of lipid biomarkers. In particular, fecal steroids that are preserved as stable compounds in paleosols and sediments, will serve as indicators of the local presence of relevant animal species such as horse, yak, cattle, sheep and goat.The successful implementation of the intended combination of geomorphological, pedological and geochemical methods will also contribute an important new approach to the identification of anthropogenic signals in paleoclimate reconstructions. This contribution will be highly relevant, as the existing uncertainties in the reconstruction of the late Holocene paleoclimatic development of Mongolia derive mainly from the interference of climatic and anthropogenic signals in the proxy data that are hardly separable by existing methods.

• DFG Programme: Research Grants