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.

古环境研究对于理解长时间尺度下的生物多样性变化，以及评估人类活动与环境因子的相对重要性至关重要。沉积DNA（Sedimentary DNA，sedDNA）是古生态学领域的新兴研究手段，现已被证实可作为花粉与大化石记录的补充方法，用于探究过去的群落变化。基于沉积DNA的古环境重建通常依赖指示类群或专家经验，但定量生态学分析可提供更为客观的研究结果。本研究通过分析沉积DNA，探究了过去6400年间阿尔卑斯山区某高海拔湖泊流域内的植物群落演变轨迹。研究整合了古今植物物种组成数据，以及沉积学与地球化学记录，以评估畜牧活动等人类活动以及温度、土壤演化等非生物因子的相对影响。在过去6400年间，研究团队观测到植物群落发生了显著变化，其主要驱动因素为土壤演化与畜牧活动。约4500年前的晚全新世时期，研究团队检测到一次对应农牧混合景观形成的突发性植被转变，山地森林与高大草本群落自此被灌丛与放牧草地所取代。本研究结果凸显了山地人类活动对当地植物群落长期演替的重要影响。沉积DNA数据结合其他古环境代用指标与现存植物群落数据，可作为重建过去植被覆盖历史的有效手段。将其与传统研究手段相结合，可为深入理解人类活动与环境因子驱动下的长期生态系统动态提供富有启示的研究视角。