A new modern pollen dataset over Issyk-Kul, Asia’s largest upland lake: Questioning taphonomy, spatial distribution and potential for local climate reconstruction

A new modern pollen dataset from one of the world’s highest alpine lakes, Lake Issyk-Kul in Central Asia, is analysed for taphonomy, spatial distribution and its climate reconstruction potential. The dataset includes samples from moss polsters, terrestrial muds and the lake sediment surface. Comparison of assemblage pairs of moss and terrestrial muds and richness analysis reveal a minor taphonomy influence. A comparison of terrestrial and lacustrine samples indicates that Artemisia is widely over-represented in lacustrine sediment. It is recommended to exclude this taxon from the counting sum and to increase the sums to avoid obscuring information from other taxa. Long-distance transport is evident for Artemisia , Amaranthaceae and Ephedra ; while some taxa reflect azonal vegetation, for example, Hippophae rhamnoides, Betula, Salix and Ulmus . The dataset distinguishes three vegetation types: Picea forest, vegetation along river and lake shores and distant steppe. Elevation transects across the Picea forest belt (now >300 m above the lake) contribute specifically to reconstruct its past elevation and to highlight periods when this belt was near the shore. Pollen grain concentrations are very high in the lake sediment, especially in the centre, probably due to lake-effect precipitation with a minor contribution of fine-grained sediment focussing. Picea pollen and stomata show a good potential for palaeovegetation reconstruction and palaeoclimate quantification, especially for precipitation; while Artemisia over-representation and presence in various vegetation types, suggest that it would make a poor indicator. Our results constitute a significant data corpus for the Eurasian Modern Pollen Database for community use and suggest that the centre of the lake is the best location for obtaining a meaningful pollen palaeo-record.