The long-term trajectories of the socio-ecosystems: past dynamics and modern legacies

• INT102 • The weed flora of Iron Age and Gallo-Roman hulled wheats (Triticum spelta L., Triticum dicoccon Schrank.): changing patterns related to écological conditions of the fields, harvesting techniques, crop processing and storage? > K. Kai Julian WIETHOLD
Content : WIETHOLD, Julian, INRAP, Direction scientifique et technique, Laboratoire archéobotanique de Metz, France
MATTERNE, Véronique, AASPE-CNRS/MNHN, Paris, France
HASSLINGER, Nadja, Kulturzentrum Archäologiepark BELGINUM, Morbach-Wederath, Germany

Hulled wheats (Triticum dicoccon [L.] Schrank., Triticum spelta L., Triticum monococcum L.) have played a major role in Iron Age and Gallo-Roman agriculture. During late Iron Age and the Gallo-Roman period especially spelt (Triticum spelta L.) was a major crop; in many archaeobotanical assemblages spelt was particularly frequent and recorded in high numbers. Hulled wheats like spelt do require several post-harvesting steps of cleaning and dehusking before the grain was ready for milling and human consumption. Crop-processing by-products from these steps of post-harvest treatment, especially remains from dehusking spelt, are giving evidence of the weed flora of the spelt fields. Large-sized fruits and seeds are often more common than small-sized seeds, which were partially eliminated during earlier steps of crop processing like winnowing and sieving.
In archaeobotanical assemblages the weed flora of winter-cultivated spelt is characterized by typical segetal weeds like corncockle (Agrostemma githago L.), rye brome (Bromus secalinus L.), field brome (Bromus arvensis L.), black bindweed (Fallopia convolvulus (L.) Á.Löv.), but also by other plants known today from meadows and grasslands like field scabious (Knautia arvensis L.) and brown knapweed (Centaurea jacea agg.) We are suggesting that these species were also formerly winter crop weeds of spelt cultivation. They disappeared later, during medieval and early modern times, from the crop fields when mouldboard ploughing and harvesting techniques developed and crop processing eliminated more efficiently large-seeded diaspores. Furthermore, a decrease of spelt cultivation and a switch to naked wheats and rye cultivation changed the weed flora of winter crop fields.
During Roman times, the rapid expansion of winter crop large-seeded weeds like corncockle, rye-brome, field scabiosa, brown knapweed and others could have been favoured by post-harvesting techniques like sieving (instead of winnowing), fertilization of the fields with manure and by harvesting with the vallus, the gallo-roman harvesting machine, which allowed harvesting large spelt fields with less manpower. The gallo-roman agricultural system in the Roman province Belgica was highly dependent on large villa complexes cultivating spelt, naked wheat and hulled barley as major crops. Archaeobotanical studies allow reconstructing at least in parts the ancient weed flora and all steps of the chaîne opératoire from harvesting to storage, milling and consumption.
• INT103 • Digging further into the past for spatialising forests age ecosystems
Content : ERTLEN, Damien, LIVE, CNRS, Strasbourg University, France
KELLER, Benjamin, LIVE, CNRS, Strasbourg University, France
ROBIN, Vincent, LIEC, CNRS, Lorraine University, France
SCHWARTZ, Dominique, LIVE, CNRS, Strasbourg University, France
HERRAULT, Pierre-Alexis, LIVE, CNRS, Strasbourg University, France

Linking biodiversity or ecological parameters with the age of ecosystems has become a classic theme of Historical Ecology. The maximum age of the forest ecosystem is usually determined with the help of old maps. In France the « Etat major » maps from the middle of the nineteen century are now a reference because they are accurately surveyed and easy to georeference. Moreover, the nineteen century is, in Europe, a period of maximum extension for forest ecosystems and this century timescale is appropriate to highlight the effects of age on the forest ecosystem. Nonetheless we propose in this study to jump further in the past. Few older maps series are available. In the eighteen century maps either cover a small piece of land or are inaccurate. With LIDAR technology we detected and mapped on wide territories all agrarian inherited microtopography such as ridge and furrows, slopped terraces and stone walls. Trenches and geoarchaeology studies provided in most cases a medieval Age. By extrapolation we propose a map of the forest at a millennial scale. Consequently, we are ready to explore the ecology of very old forests.
• INT104 • Evolution of forest stand composition in Pays de Bitche (Moselle, France) from 18th century to present : legacy of past forest management > P. Pierre MONTPIED
Content : MONTPIED, Pierre, SILVA, INRAE, AgroParisTech, Lorraine University, France
DUPOUEY, Jean-Luc, SILVA, INRAE, AgroParisTech, Lorraine University, France
ROCHEL, Xavier, LOTERR, Université de Lorraine, France
RIVIERE, Sébastien, SILVA, INRAE, AgroParisTech, Lorraine University, France
Context: In the Bitche region (Moselle, France), forest management methods evolved considerably from the 18th century to the present day, moving from coppice with standards to regular stands in response to changes in resource demand. This has resulted in a decrease of harvesting intensity, mainly due to the virtual disappearance of demand for wood energy for industry (forges, glassworks) or inhabitants (firewood) and a greater demand for timber. At the same time, the preference for certain species have evolved too, with oak being preferred to beech for timber, for example.
Questions: Have the relative proportions of beech and oak changed in favor of oak since the 18th century? Do these proportions depend on the former use of the forests (forges, glassworks factories, others)?
Methods: From 18th century hammering registers listing the trees reserved after cutting, some of them containing sketches of the exploited plots ("cuts"), we were able to relocate these plots in the current forests. A dendrometric inventory was carried out in these cuts in order to compare the tree species composition in the 18th century with the present one.
Main result: between the 18th century and the present, there has been a rebalancing of the composition of beech and oak: where beech was scarce, it has increased and, conversely, where it was dominant, it has decreased.
• INT105 • Analysing the present to understand the past and scenariorise the future – the contributions of tree ring and charcoal science > O. Oliver NELLE
Content : NELLE, Oliver, State Office for Cultural Heritage Baden-Wuerttemberg, Germany
MILLION, Sebastian, State Office for Cultural Heritage Baden-Wuerttemberg, Germany

Working with archaeological and historical material from the human past has a twofold perspective: one perspective backwards to understand developments and dynamics in the past, to increase awareness of the shaping of human-environment interactions. And the perspective towards the future: we want to learn from the past for now and tomorrow. In this contribution, we stress the importance of modern analogues from the present for an improved understanding of past ecological processes and interactions between humans and ecosystems, with examples from dendro science (the study of tree rings) and anthracology (the study of wood charcoals). In the combination of data from the present and the past we can scenariorise the future: to come up with (different) scenarios in a changing world while being aware of the long-term changes which shaped current ecosystems. In the archaeological wood remains information is stored of (pre-)historic woodland composition, woodland management as well as openness of the landscape. Human action has left imprints until today: certain management practices promoted species which became rare nowadays and are protected. The protection of woodlands vs. the sustainable use of wood resources is discussed in the light of some lessons from the past, which in turn are substantiated by the study of modern trees and woodlands.
• INT106 • Identifying, characterizing and managing future forest refugia in European mountain ecosystems > C. Cecile REMY
Content : REMY, Cécile, Institute of Geography, Augsburg University, Augsburg, Germany
THOM, Dominik, School of Life Sciences, Technical University of Munich, Freising, Germany
RIUS, Damien, Laboratoire Chrono-Environnement, University of Bourgogne-Franche-Comte, Besançon, France
BUERMANN, Wolfgang, Institute of Geography, Augsburg University, Augsburg, Germany
MILLET, Laurent, Laboratoire Chrono-Environnement, University of Bourgogne-Franche-Comte, Besançon, France
SEIDL, Rupert, Berchtesgaden National Park, Berchtesgaden, Germany

Mountain forest ecosystems provide multiple ecological services on a global scale but are today threatened by climate change and increasingly frequent and severe disturbances. Providing concrete tools to help conserve these ecosystems is now becoming a major challenge. In the context of ongoing climate change, forest refugia (i.e. isolated populations that may persist in restricted areas outside of their contracted range) may play a fundamental role to sustain long-term communities viability, minimizing the potential deleterious species interactions and avoiding regional species extinctions However, the spatial heterogeneity and the complexity of interactions in these mountain ecosystems severely restrict our ability to anticipate the future of mountain forests and to identify potential future forest refugia.
To provide tools for the conservation of these future forest refugia, three challenges must then be addressed: 1) a better understanding the migration/expansion/retreat mechanisms of tree species and communities, 2) improving projections of vegetation and disturbances dynamics in these complex environments, 3) creating management strategies that integrate the different socio-economic and ecological challenges of our century. We chose Berchtesgaden National Park in Germany as a pilot study area to carry out our study.
In our project, we propose a multidisciplinary approach to study the interactions between climate change, disturbance regimes and vegetation in the past through palaeoecological analyzes and in the future through simulations using the individual-based iLand model of forest landscape dynamics. These two complementary approaches will highlight the environmental changes leading to reduced resilience and potential tipping points and ultimately create forest management scenarios allowing the maintenance of future forest refugia and associated habitats and services.
• INT107 • Will the human footprint ever disappear? Two millennia of Roman influence on vegetation, soils and seed banks dynamics in Mediterranean grasslands. > T. Thierry DUTOIT
Content : DUTOIT, Thierry, Avignon University, Aix-Marseille University, CNRS, IRD, IMBE, Avignon, France
BOULY, Ilona, Avignon University, Aix-Marseille University, CNRS, IRD, IMBE, Avignon, France
SAATKAMP, Arne, Aix-Marseille University, Avignon University, CNRS, IRD, IMBE, Marseille, France
VIDALLER, Christel, Avignon University, Aix-Marseille University, CNRS, IRD, IMBE, Avignon, France

Former human land-uses are identified as important factors determining vegetation of European semi-natural grasslands. Nevertheless, little is known about the long-term influence of these impacts on plant dynamics, soils and their seed banks. The aims of this study were to assess whether vegetation, soil physico-chemical characteristics and seed banks remain influenced over time in Mediterranean grasslands formerly impacted by ancient sheep corrals dating from Roman to modern times. Our results shown that soils were persistently influenced by former land uses resulting in a significant elevated fertility (phosphorus, organic matter, etc.), seed bank density and species richness even in former Roman sheep corrals abandoned 1500 years ago. Present plant community composition, species-richness and diversity reflect time after abandonment of sheep corrals and are linked to the long-term persistence of eutrophication from historical sheep concentrations. These results questions the relevance of global plant succession models and for application purposes, long term human legacies must be take into account in conservation and restoration plans of semi natural grasslands.
• INT108 • Beech (Fagus sylvatica) in Northwest France during the Holocene: climatic and anthropogenic distribution processes from botanical remains preserved in sedimentary archives > D. Dominique MARGUERIE
Content : MARGUERIE, Dominique, ECOBIO, CNRS, Rennes 1 University, Rennes, France
MARCOUX, Nancy, CReAAH, CNRS, Rennes 1 University, Rennes, France
LANOS, Philippe, Archéosciences, CNRS, Bordeaux-Montaigne University, Bordeaux, France
GAUDIN, Loïc, ArkéoMap, CReAAH, CNRS, Rennes 1 University, Rennes, France
BARBIER-PAIN, Delphine, INRAP, CReAAH, CNRS, Rennes 1 University, Rennes, France
AOUSTIN, David, CReAAH, CNRS, Rennes 1 University, Rennes, France
SEIGNAC, Hélène, INRAP, CReAAH, CNRS, Rennes 1 University, Rennes, France
GUITTON, Véronique, ECOBIO, CNRS, Rennes 1 University, Rennes, France

Paleoecology makes an important contribution to the understanding of vegetation dynamics.
Various studies using pollen and wood (charcoal) records show significant correlations between Holocene plant diversity, climate and human activities.
Together with the Oak, the Beech is today a major component of the forests in Northwestern France. However, this region offers limiting conditions for the establishment of Beech in relation to the coolness of the sites, making this species particularly sensitive to natural and anthropogenic environmental variables.
For several years, a research project has been compiling well-dated paleobotanical records of pollen and charcoal of Beech over the last 8 millennia, constituting two georeferenced databases. North-western France is very rich in high-resolution paleobotanical data; the sampling contexts being peat bogs and archaeological sites. It is therefore possible to reconstruct in great detail the vegetation changes and the dynamics of Beech in long-term trends.
One of the objectives of our project is to identify the anthropogenic and abiotic factors that have modulated the development of Beech. Although the representation of Beech remains is modest during the Holocene, some spatio-temporal differences can be observed. The representation of Beech is high in the Roman period both in pollen and charcoal data. Due to the current climate change, we fear that the range of Beech in western France will decrease in the coming decades.
• INT109 • Limestone versus sandstone environments: which heritages from past charcoal making activities in current temperate forest soils? > A. Anne POSZWA
Content : POSZWA, Anne, LIEC, CNRS, Lorraine University, Nancy, France
GEBHARDT, Anne INRAP, LIEC, CNRS, Lorraine University, Nancy, France
OLIVEIRA, Cláudia, LIEC, CNRS, Lorraine University, Metz, France
ROBIN, Vincent, LIEC, CNRS, Lorraine University, Metz, France
GOCEL-CHALTE, David, OPE, Bure, France
LORGEOUX, Catherine, Georessources, CNRS, Lorraine University, Nancy, France
RAZAFITIANAMAHARAVO, Angelina, LIEC, CNRS, Lorraine University, Nancy, France
GUEROLD, François, LIEC, CNRS, Lorraine University, Metz, France
MANSUY-HUAULT, Laurence, LIEC, CNRS, Lorraine University, Nancy, France

In Lorraine (North-east of France), the intense use of wood resources in the past has left its mark on the current forests in areas rich in charcoal production sites (CPS). Locally, charcoal residues still form a specific unit at the soil surface that could modify soil capacity to store nutrients, pollutants or water. Our work aims to assess the physicochemical properties of current soils impacted by residual charcoals from CPS dated from the 19th century, in two contrasted geological and pedological contexts: on acid, sandy soils developed from sandstones and on clayed soils developed from limestones.
Our results suggest that on limestone, charcoal residues are improving soil properties. Compared to soils located uphill (considered as references, not affected by charcoals), the potential capacity of soils to store nutrients is higher in the CPS, in relation with the carbon concentration increase. The soils in CPS are also enriched in phosphorous (P) and calcium (Ca). On sandstone, except in one CPS, no significant difference was observed between soils on CPS and uphill reference soils. This difference is attributed to higher drainage of ashes through the sandy acidic soils developed on sandstone. Micromorphological studies demonstrate numerous large and fresh charcoal fragments with no evident refitting characteristics which could suggest that more reactive micro charcoals could also have been leached deeper in the profile.
On sandstones, although total PAH concentrations are not significantly different uphill and in the CPS, the distribution of PAHs is not identical by soil. Phenanthrene, the dominant PAH measured in CPS soils, seems to be a relevant marker of charcoal making activities. PAH analyses are in progress on carbonates. The results will soon allow to test this hypothesis.
More globally, the transfer of nutrients and pollutants from soils to plants and surface waters will be discussed.