Effects of forest invasion and retreat on tundra biodiversity inferred from sedimentary ancient DNA of lake Levinson Lessing, Taymyr Peninsula, Russia

One of the consequences of the amplified warming of the arctic ecosystems is tundra “greening” and northward expansion of Siberian boreal forests. However, it is still challenging to predict how northern tundra biodiversity will change with the ongoing climate warming as models usually overestimate forest invasion. The investigation of Quaternary records spanning different Pleistocene glacial and interglacial cycles can provide unique insights on past diversity dynamics following forest invasion and retreat events. Therefore, by “looking backward to look forward“, reconstruction of past vegetation can help to forecast the effects of global warming on northern biodiversity.In 2017, a 46 m core was recovered from the Lake Levinson Lessing located in the tundra of the far north Taymyr Peninsula (northern Central Siberia), the upper 38 m of which span the last 62ka continuously and with a rather constant sedimentation rate. A high resolution of 84 subsamples were collected from the lake sediment core with the aim to characterise biodiversity changes between glacials and interglacials in Russian Arctic during Late Quaternary. We studied pollen and non-pollen-palynomorphs and extracted the ancient DNA (sedaDNA), from the same sediment core samples. We also investigated past vegetation composition changes by a plant metabarcoding approach (chloroplast trnL P6 loop). We compared both pollen and sedaDNA signals to reconstruct changes in biodiversity in the Taymyr Peninsula emphasizing changes in diversity during forest invasion and retreat events.