Data from: Reconstructing long-term human impacts on plant communities : an ecological approach based on lake sediment DNA

Paleoenvironmental studies are essential to understand biodiversity changes over long timescale and to assess the relative importance of anthropogenic and environmental factors. Sedimentary DNA (sedDNA) is an emerging tool in the field of paleoecology and has proved to be a complementary approach to pollen and macroremains for investigating past community changes. SedDNA-based reconstructions of ancient environment often rely on indicator taxa or expert knowledge, but quantitative ecological analyses might provide more objective information. Here, we analysed sedDNA to investigate plant community trajectories in the catchment of a high-elevation lake in the Alps over the last 6400 years. We combined data on past and present plant species assemblages along with sedimentological and geochemical records to assess the relative impact of human activities, through pastoralism, and abiotic factors (temperature and soil evolution). Over the last 6,400 years, we identified strong variations in plant communities, mostly related to soil evolution and pastoral activities. An abrupt vegetation change corresponding to the establishment of an agro-pastoral landscape was detected during the Late Holocene, about 4,500 years ago, with the replacement of mountain forests and tall-herb communities by heathlands and grazed lands. Our results highlight the importance of anthropogenic activities in mountain area for the long-term evolution of local plant assemblages. SedDNA data, associated with other paleoenvironmental proxies and present plant assemblages, appear as a relevant tool to reconstruct past plant cover history. Their integration, in complement to classical tools, offers interesting perspectives for a better understanding of long-term ecosystem dynamics under the influence of Human-induced and environmental drivers.