Palaeoecological interpretation of a Late Holocene sediment sequence from the alpine belt of the southern Mongolian Altai Mountains

Lay summary authored by Sven Goenster-Jordan. Read the full paper here: http://doi.org/10.5334/oq.90.

Palaeoecology is a scientific discipline that contributes to a better understanding of interrelations between organisms and their environment during past geological times. The Altai Mountains, located in the center of the Asian continent and inhabited by nomads for thousands of years, are well suited for palaeoecological studies due to their location at the interface of two global climate systems, the North Atlantic climate system from the West and the Pacific climate system from the East. The dominance of one of these systems has varied over time, so that precipitation and temperature in the Altai have changed repeatedly over the millennia. Numerous studies on the Holocene climate history have been carried out in the Altai, most of them with a focus on the northern and southern Chinese part of the mountain range. With records on temperature and humidity variations derived from a soil-sediment profile in the alpine belt of the southern Mongolian Altai, our study complements the picture of the Altai’s climate and environmental history for the late Holocene. To detect such variations, fossil pollen grains in combination with age determinations of organic matter sampled from the soil-sediment profile provided information on regional vegetation changes during the last 2600 years. Pollen is very diverse in size, shape and surface structure and can be assigned to the respective plant species or at least genera based on these characteristics. Some plants and plant communities identified by pollen analyses have special climatic requirements, so that changes in pollen composition indicate changes in temperature and humidity conditions over time.

Overview of the summer pasture at Tsunkhul Lake in the southern Mongolian Altai Mountains. Photo credit: S. Goenster-Jordan.

The characteristics of the soil-sediment profile of the investigated site helped to make assumptions about previous climatic conditions. Based on the pollen data and soil-sediment characteristics, a warm and dry climate predominated between 2600 and 2250 years before present (i.e. 1950), followed by a cool and humid phase that lasted until about 130 years before present. Since then the climate is characterized again by warmer and drier conditions. Such an observation of the mode of climate variability together with its temporal sequence has not been observed in the Altai so far, with the exception of a study in the Chinese southern Altai 50 km away. Additionally, an influence of livestock grazing on the vegetation during the last 2600 years could be shown. This not only indicates a long-term human impact, but also that the climatic influence on the vegetation was predominant.

Full Paper: Goenster-Jordan, S., Urban, B. and Buerkert, A., 2022. Palaeoecological Interpretation of a Late Holocene Sediment Sequence from the Alpine Belt of the Southern Mongolian Altai Mountains. Open Quaternary, 8(1), p.2. DOI: http://doi.org/10.5334/oq.90

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