From the microscope to the landscape: soil sequences from the second half of the Holocene as indicators of past ecological dynamics

International audienceSoil complexes have components and properties that belong to both organic and mineral worlds. They constitute diverse habitats and provide water and energy for biological and microbiological activity. Thus, as a real ecotone, a soil is a dynamic ecological system and its qualities are important for mankind.In historical ecology, past human impacts are studied on current soil properties. However, when researches are focused on long term environmental evolution, another important aspect has to be developed: the study of buried paleosol sequences dated by archaeological artefacts. Data gathered over the last two decades during preventive archaeological excavations in Lorraine, have shown, from the field to the microscope, that these artefacts are good indicators for tracing ancient biotic and abiotic ecological factors of past soil ecosystems.From examples of ancient urban, rural and pre-industrial settlements, we will highlight the human strong impact on soils by deforestation, drainage or management of the natural landscape. Archaeo-pedology brings out the early strong anthropogenic influence on soil in urban context, and reveals also that the now protected typical grazed dry grassland of the calcareous Sion plateau has been deforested since the Bronze-Age. Across Lorraine, two main soil evolution phases can now be recognized: a late Iron-Age strong erosion episode and colluviation processes, and an early Roman soil desiccation period and luvisol degradation. Then, within the second half of the Holocene, soil evolution seems to be mainly a human derived process, even if climate crises and local physical factors could have reinforced them.We invite then the ecologist community to take fully into account these under-used archaeo-pedological data. Better understanding of key pedological factors controlling past soil evolution may help future soil management and ecological restoration.https://www.youtube.com/watch?v=cb48b2SEe7s&feature=youtu.b