Holocene reconstruction of plant communities and impacts of human activity from sedaDNA in the Austrian Alps

The Alps contain highly biodiverse ecosystems including a large number endemic flora. As a result of climate change and anthropogenic activities, such ecosystems are at risk from upward vegetation displacement and species loss. Extensive archaeological research in the Eastern Alps has documented human settlement from ~5500 years ago driven by salt and copper mining; which has caused significant impact on the ecosystems through mining, deforestation, and pastoral farming. To elucidate the effects of climate change and anthropogenic activities on plant biodiversity, multi-proxy reconstructions have been carried out throughout the Western Alps . Despite this research, the palaeoecological history of the Eastern Alps is relatively understudied. Consequently, we are limited in our understanding of how climate change and human impact have affected past biodiversity and the formation of the contemporary vegetation in this region. Here, we focus on the Austrian sub-alpine lake, Großer Winterleitensee located at the Easternmost margin of the Alps; only locally glaciated during the Pleistocene. We applied sedimentary ancient DNA (sedaDNA) metabarcoding to reconstruct Holocene plant community dynamics within the lake catchment. These data, in conjunction with local temperature reconstructions, sediment elemental composition, magnetic susceptibility, and loss-on-ignition analyses, allowed us to identify key intervals of plant diversity change. Two such intervals begin at samples dated ~5500 cal. yr BP and ~2200 cal. yr BP, coinciding with Neolithic and Iron Age settlement phases in the area. Palaeoecological reconstructions of plant biodiversity and their responses to climate change and anthropogenic pressures may be able to provide essential information for future conservation purposes.