Ecological stability during the LGM and the mid-Holocene in the Alpine Steppes of Tibet? |
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| Authors: | Georg Miehe Sabine Miehe Kerstin Bach Jürgen Kluge Karsten Wesche Yang Yongping Liu Jianquan |
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| Institution: | aFaculty of Geography, University of Marburg, Deutschhausstraße 10, D-35032 Marburg, Germany;bSenckenberg Museum of Natural History Görlitz, PoB 300 154, D-02806 Goerlitz, Germany, Germany;cInstitute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650204, PR China;dInstitute of Molecular Ecology, MOE Key Laboratory of Arid and Grassland Ecology, School of Life Science, Lanzhou University, Lanzhou 730000, Gansu, PR China |
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| Abstract: | Arid and Alpine ecosystems are known for extreme environmental changes during the Late Quaternary. We hypothesize that the world's largest Alpine arid ecosystem however, the Alpine Steppes of the Tibetan highlands, remained ecologically stable during the LGM and the mid-Holocene. This hypothesis is tested by distributional range of plant species, plant life forms and rate of endemism. The set of character species has a precipitation gradient between 50 and 350 mm/a, testifying for resilience to precipitation changes. 83% of the species have a wider vertical range than 1000 m used as a proxy for resilience to temperature changes. 30% of the species are endemic with 10 endemic genera, including plate-shaped cushions as a unique plant life form. These findings are in line with palaeo-ecological proxies (δ18O, pollen) allowing the assumption that Alpine Steppes persisted during the LGM with 3 to 4 K lower summer temperatures.During the mid-Holocene, forests could have replaced Alpine Steppes in the upper catchments of the Huang He, Yangtze, Mekong, Salween and Yarlung Zhangbo, but not in the interior basins of the north-western highlands, because the basins were then flooded, suppressing forests and supporting the environmental stability of this arid Alpine grassland biome. |
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| Keywords: | Steppe Qinghai&ndash Tibet Plateau Grazing Endemics LGM Mid-Holocene optimum |
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